U.S. patent application number 15/400776 was filed with the patent office on 2017-08-17 for method and apparatus for tissue ablation.
The applicant listed for this patent is Virender K. Sharma. Invention is credited to Virender K. Sharma.
Application Number | 20170231678 15/400776 |
Document ID | / |
Family ID | 51210191 |
Filed Date | 2017-08-17 |
United States Patent
Application |
20170231678 |
Kind Code |
A1 |
Sharma; Virender K. |
August 17, 2017 |
Method and Apparatus for Tissue Ablation
Abstract
Methods of ablating endometrial tissue are disclosed. The
methods include providing an ablation device that has a catheter
with a hollow shaft through which an ablative agent can travel, a
first positioning element, and a second positioning element
positioned on the catheter distal to the first positioning element.
The second positioning element is a disc shaped wire mesh and has a
diameter in a range of 0.1 mm to 10 cm.
Inventors: |
Sharma; Virender K.;
(Paradise Valley, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sharma; Virender K. |
Paradise Valley |
AZ |
US |
|
|
Family ID: |
51210191 |
Appl. No.: |
15/400776 |
Filed: |
January 6, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14158687 |
Jan 17, 2014 |
9561067 |
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15400776 |
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13486980 |
Jun 1, 2012 |
9561066 |
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14158687 |
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12573939 |
Oct 6, 2009 |
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13486980 |
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61753831 |
Jan 17, 2013 |
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61493344 |
Jun 3, 2011 |
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61102885 |
Oct 6, 2008 |
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Current U.S.
Class: |
604/23 |
Current CPC
Class: |
A61B 5/03 20130101; A61B
2090/064 20160201; A61B 2017/00203 20130101; A61M 2205/3331
20130101; A61M 25/04 20130101; A61B 2018/00488 20130101; A61B
2018/00327 20130101; A61B 2018/00577 20130101; A61B 5/6853
20130101; A61B 18/04 20130101; A61B 2017/00274 20130101; A61M
2210/1433 20130101; A61B 2562/0233 20130101; A61B 2017/00818
20130101; A61B 2018/00541 20130101; A61B 2018/00648 20130101; A61B
2018/00494 20130101; A61B 2018/00744 20130101; A61B 2562/0204
20130101; A61B 17/24 20130101; A61B 5/1076 20130101; A61B
2018/00642 20130101; A61M 25/1011 20130101; A61M 2205/3368
20130101; A61B 2018/00559 20130101; A61B 2017/00973 20130101; A61B
2018/00791 20130101; A61B 2017/00084 20130101; A61B 2018/048
20130101; A61B 2018/00714 20130101; A61B 2017/4216 20130101; A61B
2017/00809 20130101; A61B 2018/00547 20130101 |
International
Class: |
A61B 18/04 20060101
A61B018/04; A61B 5/107 20060101 A61B005/107; A61M 25/04 20060101
A61M025/04 |
Claims
1. A method of ablating endometrial tissue comprising the steps of:
providing an ablation device comprising: a catheter having a hollow
shaft through which an ablative agent can travel; a first
positioning element attached to said catheter; a second positioning
element attached to said catheter and positioned on said catheter
distal to said first positioning element, wherein said second
positioning element is a balloon; at least one infusion port on
said catheter for delivery of said ablative agent to said
endometrial tissue; and a controller comprising a microprocessor
for controlling the delivery of said ablative agent; inserting said
catheter through a cervix and into a uterus of a patient such that
said first positioning element is positioned in said cervix and
said second positioning element is positioned proximate a fundus or
body of said uterus; deploying said first and second positioning
elements such that said first positioning element contacts said
cervix, said second positioning element contacts a portion of said
uterus proximate said fundus or body, and said catheter and at
least one infusion port are positioned within a uterine cavity of
said patient; and delivering said ablative agent through said at
least one infusion port to ablate said endometrial tissue.
2. The method of claim 1, wherein said ablation device further
comprises at least one sensor for measuring at least one dimension
of said uterine cavity and said method further comprises the steps
of: operating said at least one sensor to measure said at least one
dimension of said uterine cavity; and using said at least one
dimension of said uterine cavity to determine an amount of said
ablative agent to deliver to said endometrial tissue.
3. The method of claim 2, wherein said at least one sensor
comprises an infrared, electromagnetic, acoustic, or radiofrequency
energy emitter and sensor.
4. The method of claim 1, wherein said first positioning element is
cone shaped and, once deployed, positions said catheter in a center
of said cervix and occludes a cervical opening.
5. The method of claim 1, wherein said first positioning element is
oval shaped, having a length in a range of 0.1 mm to 10 cm and a
width in a range of 0.1 mm to 5 cm and, once deployed, positions
said catheter in a center of said cervix and occludes a cervical
opening.
6. The method of claim 4, wherein said first positioning element is
covered by an insulated membrane for preventing an escape of said
ablative agent through said cervix and beyond said uterine
cavity.
7. The method of claim 6, wherein a segment of said catheter
includes a predetermined length and said method includes the steps
of: using said predetermined length and/or a diameter of said
second positioning element to estimate a size of said uterine
cavity; and using said estimated size of said uterine cavity to
calculate an amount of thermal energy of said ablative agent
required to ablate said endometrial tissue.
8. The method of claim 1, wherein said first and second positioning
elements are separated from endometrial tissue to be ablated by a
distance of greater than 1 mm.
9. The method of claim 1, wherein said first and second positioning
elements are within an area including endometrial tissue to be
ablated.
10. The method of claim 1, wherein said delivering of said ablative
agent is guided by predetermined programmatic instructions.
11. The method of claim 1, wherein said ablation device further
comprises at least one sensor for measuring a parameter of said
uterus and said method further comprises the steps of: operating
said at least one sensor to measure said parameter of said uterus;
and using the measure of said parameter to increase or decrease a
flow of said ablative agent to said endometrial tissue.
12. The method of claim 11, wherein said at least one sensor is any
one of a temperature, pressure, photo, or chemical sensor.
13. The method of claim 1, wherein said ablation device further
comprises a coaxial member configured to restrain said first and
second positioning elements and said step of deploying said first
and second positioning elements further comprises withdrawing said
coaxial member over said ablation device.
14. The method of claim 1, wherein said ablation device further
comprises an input device and said method further comprises using
said input device to control the delivery of said ablative
agent.
15. The method of claim 1, wherein said ablation device further
comprises at least one input port on said catheter for receiving
said ablative agent.
16. A method of ablating endometrial tissue comprising the steps
of: providing an ablation device comprising: a catheter having a
hollow shaft through which an ablative agent can travel; a first
positioning element attached to said catheter; a second positioning
element attached to said catheter and positioned on said catheter
distal to said first positioning element, wherein said second
positioning element is a balloon; at least one infusion port on
said catheter for delivery of said ablative agent to said
endometrial tissue; at least one mechanism for measuring at least
one dimension of a uterine cavity; and a controller comprising a
microprocessor for controlling the delivery of said ablative agent;
inserting said catheter through a cervix and into a uterus of a
patient such that said first positioning element is positioned in
said cervix and said second positioning element is positioned in
the uterine cavity; deploying said first and second positioning
elements such that said first positioning element contacts said
cervix, said second positioning element contacts a portion of said
uterus within said uterine cavity, and said catheter and at least
one infusion port are positioned within said uterine cavity of said
patient; operating said at least one mechanism to measure at least
one dimension of said uterine cavity; using said at least one
dimension measurement to determine an amount of ablative agent to
deliver to said endometrial tissue; and delivering said ablative
agent through said at least one infusion port to ablate said
endometrial tissue.
Description
CROSS-REFERENCE
[0001] The present application is a division application of U.S.
patent application Ser. No. 14/158,687, entitled "Method and
Apparatus for Tissue Ablation" and filed on Jan. 17, 2014, which
relies on U.S. Provisional Patent Application No. 61/753,831, of
the same title and filed on Jan. 17, 2013, for priority.
[0002] U.S. patent application Ser. No. 14/158,687 is also a
continuation-in-part of U.S. patent application Ser. No.
13/486,980, entitled "Method and Apparatus for Tissue Ablation" and
filed on Jun. 1, 2012, which relies on U.S. Provisional Patent
Application No. 61/493,344, of the same title and filed on Jun. 3,
2011, for priority.
[0003] U.S. patent application Ser. No. 13/486,980 is also a
continuation-in-part application of U.S. patent application Ser.
No. 12/573,939, entitled "Method and Apparatus for Tissue Ablation"
and filed on Oct. 6, 2009, which relies on U.S. Provisional Patent
Application No. 61/102,885, of the same title and filed on Oct. 6,
2008, for priority.
[0004] The aforementioned applications are herein incorporated by
reference in their entirety.
FIELD
[0005] The present specification relates to medical apparatuses and
procedures used in tissue ablation. More particularly, the present
specification relates to devices and methods for ablation of tissue
in hollow and solid organs comprising positioning attachments
and/or components or media capable of conducting an ablative
agent.
BACKGROUND
[0006] Ablation, as it pertains to the present specification,
relates to the removal or destruction of a body tissue, usually by
surgery or introduction of a noxious substance. Ablation is
commonly used to eliminate diseased or unwanted tissues, such as,
but not limited to, cysts, polyps, tumors, hemorrhoids, and other
similar lesions.
[0007] Colon polyps affect almost 25% of the population over the
age of 50. While most polyps are detected on colonoscopy and easily
removed using a snare, flat sessile polyps are hard to remove using
the snare technique and carry a high risk of complications, such as
bleeding and perforation. Recently, with improvement in imaging
techniques, more flat polyps are being detected. Endoscopically
unresectable polyps require surgical removal. Most colon cancer
arises from colon polyps and, safe and complete resection of these
polyps is imperative for the prevention of colon cancer.
[0008] Barrett's esophagus is a precancerous condition effecting
10-14% of the US population with gastro esophageal reflux disease
(GERD) and is the proven precursor lesion of esophageal
adenocarcinoma, the fastest rising cancer in developed nations. The
incidence of the cancer has risen over 6 fold in the last 2 decades
and the mortality rate has risen by 7 fold. The 5-year mortality
rate from esophageal cancer is 85%. Ablation of Barrett's
epithelium has shown to prevent its progression to esophageal
cancer.
[0009] Benign Prostatic Hyperplasia (BPH) is a non-cancerous
condition of the prostate defined by an increase in the number of
prostatic stromal and epithelial cells, resulting in an overall
increase in the size of the prostate. The increase in size can
constrict the prostatic urethra, resulting in urinary problems such
as an increase in urinary frequency, urinary hesitancy, urinary
retention, dysuria, and an increase in the occurrence of urinary
tract infections (UTI's). Approximately 50% of men show
histological evidence of BPH by age 50, which rises to 75% by age
80. About half of these men have symptoms. Although BPH does not
lead to cancer, it can have a significant impact on urinary health
and quality of life. Therapies aimed at alleviating the symptoms
associated with BPH include those involved with reducing prostate
size, such as transurethral microwave thermotherapy and
transurethral needle ablation, which uses RF energy. When such less
invasive therapies are ineffective, surgery, such as transurethral
resection of the prostate, often becomes necessary.
[0010] Prostate cancer is diagnosed in approximately 8% of men
between the ages of 50 and 70 and tends to occur in men as they
grow older. Men experiencing symptoms with prostate cancer often
exhibit symptoms similar to those encountered with BPH and can also
suffer from sexual problems caused by the disease. Typically, men
diagnosed with prostate cancer when the cancer is at an early stage
have a very good prognosis. Therapy ranges from active surveillance
to surgery and radiation and chemotherapy depending on the severity
of the disease and the age of the patient.
[0011] Dysfunctional uterine bleeding (DUB), or menorrhagia,
affects 30% of women in reproductive age. The associated symptoms
have considerable impact on a woman's health and quality of life.
The condition is typically treated with endometrial ablation or a
hysterectomy. The rates of surgical intervention in these women are
high. Almost 30% of women in the US will undergo hysterectomy by
the age of 60, with menorrhagia or DUB being the cause for surgery
in 50-70% of these women. Endometrial ablation techniques have been
FDA approved for women with abnormal uterine bleeding and with
intramural fibroids less than 2 cm in size. The presence of
submucosal uterine fibroids and a large uterus size have been shown
to decrease the efficacy of standard endometrial ablation. Of the
five FDA approved global ablation devices (namely, Thermachoice,
hydrothermal ablation, Novasure, Her Option, and microwave ablation
(MEA)) only microwave ablation has been approved for use where the
submucosal fibroids are less than 3 cm in size and are not
occluding the endometrial cavity and, additionally, for large uteri
up to 14 cm in width.
[0012] The known ablation treatments for Barrett's esophagus
include laser treatment, ultrasonic ablation, photodynamic therapy
(PDT) using photo-sensitizer drugs, multipolar electrocoagulation,
such as by use of a bicap probe, argon plasma coagulation (APC),
radiofrequency ablation, and cryoablation. The treatments are
delivered with the aid of an endoscope wherein devices are passed
through the channel of the endoscope or alongside the
endoscope.
[0013] Conventional techniques have inherent limitations, however,
and have not found widespread clinical applications. First, most of
the hand held ablation devices (bicap probe, APC, cryoablation) are
point and shoot devices that create small foci of ablation. This
ablation mechanism is operator dependent, cumbersome, and time
consuming. Second, because the target tissue is moving due to
patient movement, respiration movement, normal peristalsis, and
vascular pulsations, the depth of ablation of the target tissue is
inconsistent and results in a non-uniform ablation. Superficial
ablation results in incomplete ablation with residual neoplastic
tissue left behind. Deeper ablation results in complications such
as bleeding, stricture formation, and perforation. All of these
limitations and complications have been reported with conventional
devices.
[0014] For example, radiofrequency ablation uses a rigid bipolar
balloon based electrode and radiofrequency thermal energy. The
thermal energy is delivered by direct contact of the electrode with
the diseased Barrett's epithelium allowing for a relatively
uniform, large area ablation. However, the rigid electrode does not
accommodate for variations in esophageal size and is ineffective in
ablating esophageal tissue in a tortuous esophagus, proximal
esophageal lesions as an esophagus narrows toward the top, and
esophageal tissue at the gastroesophageal junction due to changes
in the esophageal diameter. Nodular disease in Barrett's esophagus
also cannot be treated using the rigid bipolar RF electrode. Due to
its size and rigidity, the electrode cannot be passed through the
scope. In addition, sticking of sloughed tissue to the electrode
impedes delivery of radiofrequency energy, resulting in incomplete
ablation. The electrode size is limited to 3 cm, thus requiring
repeat applications to treat larger lengths of Barrett's
esophagus.
[0015] Photodynamic therapy (PDT) is a two part procedure that
involves injecting a photo-sensitizer that is absorbed and retained
by the neoplastic and pre-neoplastic tissue. The tissue is then
exposed to a selected wavelength of light which activates the
photo-sensitizer and results in tissue destruction. PDT is
associated with complications such as stricture formation and
photo-sensitivity which has limited its use to the most advanced
stages of the disease. In addition, patchy uptake of the
photosensitizer results in incomplete ablation and residual
neoplastic tissue.
[0016] Cryoablation of the esophageal tissues via direct contact
with liquid nitrogen has been studied in both animal models and
humans and has been used to treat Barrett's esophagus and early
esophageal cancer. A spray catheter that directly sprays liquid
N.sub.2 or CO.sub.2 (cryoablation) or argon (APC) to ablate
Barrett's tissue in the esophagus has been described. These
techniques suffer the shortcoming of the traditional hand-held
devices. Treatment using this probe is cumbersome and requires
operator control under direct endoscopic visualization. Continuous
movement in the esophagus due to respiration or cardiac or aortic
pulsations or movement causes an uneven distribution of the
ablative agent and results in non-uniform and/or incomplete
ablation. Close or direct contact of the catheter to the surface
epithelium may cause deeper tissue injury, resulting in
perforation, bleeding, or stricture formation. Too distant a
placement of the catheter due to esophageal movement will result in
incomplete Barrett's epithelium ablation, requiring multiple
treatment sessions or buried lesions with a continued risk of
esophageal cancer. Expansion of cryogenic gas in the esophagus
results in uncontrolled retching which may result in esophageal
tear or perforation requiring continued suctioning of cryogen.
[0017] Colon polyps are usually resected using snare resection with
or without the use of monopolar cautery. Flat polyps or residual
polyps after snare resection have been treated with argon plasma
coagulation or laser treatment. Both these treatments have the
previously mentioned limitations. Hence, most large flat polyps
undergo surgical resection due to the high risk of bleeding,
perforation, and residual disease using traditional endoscopic
resection or ablation techniques.
[0018] Most of the conventional balloon catheters traditionally
used for tissue ablation either heat or cool the balloon itself or
a heating element such as radio frequency (RF) coils mounted on the
balloon. This requires direct contact of the balloon catheter with
the ablated surface. When the balloon catheter is deflated, the
epithelium sticks to the catheter and sloughs off, thereby causing
bleeding. Blood can interfere with the delivery of energy, i.e.
energy sink. In addition, reapplication of energy will result in
deeper burn in the area where superficial lining has sloughed.
Further, balloon catheters cannot be employed for treatment in
non-cylindrical organs, such as the uterus or sinuses, and also do
not provide non-circumferential or focal ablation in a hollow
organ. Additionally, if used with cryogens as ablative agents,
which expand exponentially upon being heated, balloon catheters may
result in a closed cavity and trap the escape of cryogen, resulting
in complications such as perforations and tears.
[0019] Metal stents have been used for palliation of malignant
obstruction. However, tumor ingrowth continues to be a significant
problem affecting stent longevity. Covered stents provide a good
solution for in-growth, however, tumor compression can lead to
stent blockage and dysfunction. Traditional coverings on the
stents, such as silicone, have poor thermal conductivity and do not
allow for successful thermal therapy after the stent has been
deployed.
[0020] Accordingly, there is a need in the art for improved devices
and methods for delivering ablative agents to a tissue surface, for
providing a consistent, controlled, and uniform ablation of the
target tissue, and for minimizing the adverse side effects of
introducing ablative agents into a patient. What is also needed is
a stent that provides the ability to deliver ablative therapy to an
inoperable tumor post deployment.
SUMMARY
[0021] The present specification is directed toward a device to
perform ablation of endometrial tissue, comprising a catheter
having a shaft through which an ablative agent can travel, a first
positioning element attached to said catheter shaft at a first
position, wherein said first positioning element is configured to
center said catheter in a center of a cervix, and an optional
second positioning element attached to said catheter shaft at a
second position, wherein the shaft comprises a plurality of ports
through which said ablative agent can be released out of said shaft
and wherein said ports are located between said first position and
second position.
[0022] Optionally, the first positioning element is conical. The
first positioning element comprises an insulated membrane which can
be configured to prevent an escape of thermal energy through the
cervix. The second positioning element is disc shaped. The second
positioning element has a dimension which can be used to determine
a uterine cavity size. The second positioning element has a
dimension which can be used to calculate an amount of thermal
energy needed to ablate the endometrial tissue. The device also
includes at least one temperature sensor, which can be used to
control delivery of the ablative agent, such as steam.
[0023] Optionally, the second positioning element is separated from
endometrial tissue to be ablated by a distance of greater than 0.1
mm. The first positioning element is a covered wire mesh. The first
positioning element is comprises a circular body with a diameter
between 0.1 mm and 10 cm. The second positioning element is oval
and wherein said oval has a long axis between 0.1 mm and 10 cm and
a short axis between 0.1 mm and 5 cm.
[0024] In another embodiment, the present specification is directed
toward a device to perform ablation of endometrial tissue,
comprising a catheter having a hollow shaft through which steam can
be delivered, a first positioning element attached to said catheter
shaft at a first position, wherein said first positioning element
is conical and configured to center said catheter in a center of a
cervix, an optional second positioning element attached to said
catheter shaft at a second position, wherein the second positioning
element is disc shaped, a plurality of ports integrally formed in
said catheter shaft, wherein steam can be released out of said
ports and directed toward endometrial tissue and wherein said ports
are located between said first position and second position; and at
least one temperature sensor.
[0025] Optionally, the second positioning element has a dimension,
which can be used to determine a uterine cavity size. The second
positioning element has a dimension, which can be used to calculate
an amount of thermal energy needed to ablate the endometrial
tissue. The temperature sensors are used to control delivery of
said ablative agent. The first positioning element comprises wire
mesh. The second positioning element has a disc shape that is oval
and wherein said oval has a long axis between 0.1 mm and 10 cm and
a short axis between 0.1 mm and 5 cm.
[0026] The present specification is also directed toward a device
to perform ablation of tissue in a hollow organ, comprising a
catheter having a shaft through which an ablative agent can travel;
a first positioning element attached to said catheter shaft at a
first position, wherein said first positioning element is
configured to position said catheter at a predefined distance from
the tissue to be ablated; and wherein the shaft comprises one or
more port through which said ablative agent can be released out of
said shaft.
[0027] Optionally, the device further comprises a second
positioning element attached to said catheter shaft at a position
different from said first positioning element. The first
positioning element is at least one of a conical shape, disc shape,
or a free form shape conformed to the shape of the hollow organ.
The second positioning element has predefined dimensions and
wherein said predefined dimensions are used to determine the
dimensions of the hollow organ to be ablated. The first positioning
element comprises an insulated membrane. The insulated membrane is
configured to prevent an escape of thermal energy. The second
positioning element is at least one of a conical shape, disc shape,
or a free form shape conformed to the shape of the hollow organ.
The second positioning element has predefined dimensions and
wherein said predefined dimensions are used to determine the
dimensions of the hollow organ to be ablated. The second
positioning element has a predefined dimension and wherein said
predefined dimension is used to calculate an amount of thermal
energy needed to ablate the tissue. The device further comprises at
least one temperature sensor. The temperature sensor is used to
control delivery of said ablative agent. The ablative agent is
steam. The first positioning element is a covered wire mesh. The
first positioning element comprises a circular body with a diameter
between 0.01 mm and 10 cm. The first positioning element is oval
and wherein said oval has a long axis between 0.01 mm and 10 cm and
a short axis between 0.01 mm and 9 cm.
[0028] In another embodiment, the present specification is directed
to a device to perform ablation of tissue in a hollow organ,
comprising a catheter having a hollow shaft through which steam can
be delivered; a first positioning element attached to said catheter
shaft at a first position, wherein said first positioning element
is configured to position said catheter at a predefined distance
from the surface of the hollow organ; a second positioning element
attached to said catheter shaft at a second position, wherein the
second positioning element is shaped to position said catheter at a
predefined distance from the surface of the hollow organ; a
plurality of ports integrally formed in said catheter shaft,
wherein steam can be released out of said ports and directed toward
tissue to be ablated and wherein said ports are located between
said first position and second position; and at least one
temperature sensor.
[0029] Optionally, the first positioning element has a predefined
dimension and wherein said dimension is used to determine the size
of the hollow organ. The second positioning element has a
predefined dimension and wherein said dimension is used to
calculate an amount of thermal energy needed to ablate the tissue.
The temperature sensor is used to control delivery of said ablative
agent. The first positioning element comprises wire mesh. The
second positioning element has a disc shape that is oval and
wherein said oval has a long axis between 0.01 mm and 10 cm and a
short axis between 0.01 mm and 9 cm.
[0030] In another embodiment, the present specification is directed
to a device to perform ablation of the gastrointestinal tissue,
comprising a catheter having a shaft through which an ablative
agent can travel; a first positioning element attached to said
catheter shaft at a first position, wherein said first positioning
element is configured to position the catheter at a fixed distance
from the gastrointestinal tissue to be ablated, and wherein said
first positioning element is separated from an ablation region by a
distance of between 0 mm and 5 cm, and an input port at a second
position and in fluid communication with said catheter shaft in
order to receive said ablative agent wherein the shaft comprises
one or more ports through which said ablative agent can be released
out of said shaft.
[0031] Optionally, the first positioning element is at least one of
an inflatable balloon, wire mesh disc or cone. By introducing said
ablative agent into said ablation region, the device creates a
gastrointestinal pressure equal to or less than 5 atm. The ablative
agent has a temperature between -100 degrees Celsius and 200
degrees Celsius. The catheter further comprises a temperature
sensor. The catheter further comprises a pressure sensor. The first
positioning element is configured to abut a gastroesophageal
junction when placed in a gastric cardia. The ports are located
between said first position and second position. The diameter of
the positioning element is between 0.01 mm and 100 mm. The ablative
agent is steam. The first positioning element comprises a circular
body with a diameter between 0.01 mm and 10 cm.
[0032] In another embodiment, the present specification is directed
toward a device to perform ablation of esophageal tissue,
comprising a catheter having a hollow shaft through which steam can
be transported; a first positioning element attached to said
catheter shaft at a first position, wherein said first positioning
element is configured to abut a gastroesophageal junction when
placed in a gastric cardia; and an input port at a second position
and in fluid communication with said catheter shaft in order to
receive said steam wherein the shaft comprises a plurality of ports
through which said steam can be released out of said shaft and
wherein said ports are located between said first position and
second position. The device further comprises a temperature sensor
wherein said temperature sensor is used to control the release of
said steam. The first positioning element comprises at least one of
a wire mesh disc, a wire mesh cone, or an inflatable balloon. The
first positioning element is separated from an ablation region by a
distance of between 0 mm and 1 cm. The diameter of the first
positioning element is between 1 mm and 100 mm.
[0033] In another embodiment, the present specification is directed
to a device to perform ablation of gastrointestinal tissue,
comprising a catheter having a hollow shaft through which steam can
be transported; a first positioning element attached to said
catheter shaft at a first position, wherein said first positioning
element is configured to abut the gastrointestinal tissue; and an
input port at a second position and in fluid communication with
said catheter shaft in order to receive said steam wherein the
shaft comprises one or more ports through which said steam can be
released out of said shaft onto the gastrointestinal tissue.
[0034] Optionally, the device further comprises a temperature
sensor wherein said temperature sensor is used to control the
release of said steam. The first positioning element comprises at
least one of a wire mesh disc and a wire mesh cone. The diameter of
the first positioning element is 0.1 mm to 50 mm. The device is
used to perform non-circumferential ablation.
[0035] In another embodiment, the present specification is directed
to a device to perform ablation of endometrial tissue, comprising a
catheter having a shaft through which an ablative agent can travel;
a first positioning element attached to said catheter shaft at a
first position, wherein said first positioning element is
configured to center said catheter in a center of a cervix; and a
shaft comprises a plurality of ports through which said ablative
agent can be released out of said shaft.
[0036] Optionally, the device further comprises a second
positioning element attached to said catheter shaft at a second
position. The first positioning element is conical. The first
positioning element comprises an insulated membrane. The insulated
membrane is configured to prevent an escape of thermal energy
through the cervix. The second positioning element is disc shaped.
The second positioning element has a predefined dimension and
wherein said dimension is used to determine a uterine cavity size.
The second positioning element has a predefined dimension and
wherein said dimension is used to calculate an amount of thermal
energy needed to ablate the endometrial tissue. The device further
comprises at least one temperature sensor wherein said temperature
sensor is used to control delivery of said ablative agent. The
ablative agent is steam. The first positioning element is a covered
wire mesh. The first positioning element comprises a circular body
with a diameter between 0.01 mm and 10 cm. The second positioning
element is oval and wherein said oval has a long axis between 0.01
mm and 10 cm and a short axis between 0.01 mm and 5 cm. When
deployed, the positioning elements also serve to open up the
uterine cavity.
[0037] In another embodiment, the present specification is directed
toward a device to perform ablation of endometrial tissue,
comprising a catheter having a hollow shaft through which steam can
be delivered; a first positioning element attached to said catheter
shaft at a first position, wherein said first positioning element
is conical and configured to center said catheter in a center of a
cervix; a second positioning element attached to said catheter
shaft at a second position, wherein the second positioning element
is elliptical shaped; a plurality of ports integrally formed in
said catheter shaft, wherein steam can be released out of said
ports and directed toward endometrial tissue and wherein said ports
are located between said first position and second position; and at
least one temperature sensor.
[0038] Optionally, the second positioning element has a predefined
dimension and wherein said dimension is used to determine a uterine
cavity size. The second positioning element has a diameter and
wherein said diameter is used to calculate an amount of thermal
energy needed to ablate the endometrial tissue. The temperature
sensors are used to control delivery of said ablative agent. The
first positioning element comprises wire mesh. The second
positioning element has a disc shape that is oval and wherein said
oval has a long axis between 0.01 mm and 10 cm and a short axis
between 0.01 mm and 5 cm.
[0039] Optionally, the second positioning element can use one or
more sources of infrared, electromagnetic, acoustic or
radiofrequency energy to measure the dimensions of the hollow
cavity. The energy is emitted from the sensor and is reflected back
to the detector in the sensor. The reflected data is used to
determine the dimension of the hollow cavity.
[0040] In one embodiment, the present specification discloses a
device to be used in conjunction with a tissue ablation system,
comprising: a handle with a pressure-resistant port on its distal
end, a flow channel through which an ablative agent can travel, and
one or more connection ports on its proximal end for the inlet of
said ablative agent and for an RF feed; an insulated catheter that
attaches to said pressure-resistant port of said snare handle,
containing a shaft through which an ablative agent can travel and
one or more ports along its length for the release of said ablative
agent; and one or more positioning elements attached to said
catheter shaft at one or more separate positions, wherein said
positioning element(s) is configured to position said catheter at a
predefined distance from the tissue to be ablated.
[0041] Optionally, the handle has one pressure-resistant port for
the attachment of both an ablative agent inlet and an RF feed. The
handle has one separate pressure-resistant port for the attachment
of an ablative agent inlet and one separate port for the attachment
of an RF feed or an electrical feed.
[0042] In another embodiment, the present specification discloses a
device to be used in conjunction with a tissue ablation system,
comprising: a handle with a pressure-resistant port on its distal
end, a flow channel passing through said handle which is continuous
with a pre-attached cord through which an ablative agent can
travel, and a connection port on its proximal end for an RF feed or
an electrical field; an insulated catheter that attaches to said
pressure-resistant port of said handle, containing a shaft through
which an ablative agent can travel and one or more ports along its
length for the release of said ablative agent; and one or more
positioning elements attached to said catheter shaft at one or more
separate positions, wherein said positioning element(s) is
configured to position said catheter at a predefined distance from
the tissue to be ablated. Optionally, the distal end of said
catheter is designed to puncture the target.
[0043] In another embodiment, the present specification discloses a
device to be used in conjunction with a tissue ablation system,
comprising: an esophageal probe with a pressure-resistant port on
its distal end, a flow channel through which an ablative agent can
travel, and one or more connection ports on its proximal end for
the inlet of said ablative agent and for an RF feed or an
electrical feed; an insulated catheter that attaches to said
pressure-resistant port of said esophageal probe, containing a
shaft through which an ablative agent can travel and one or more
ports along its length for the release of said ablative agent; and
one or more inflatable positioning balloons at either end of said
catheter positioned beyond said one or more ports, wherein said
positioning balloons are configured to position said catheter at a
predefined distance from the tissue to be ablated.
[0044] Optionally, the catheter is dual lumen, wherein a first
lumen facilitates the transfer of ablative agent and a second lumen
contains an electrode for RF ablation. The catheter has
differential insulation along its length.
[0045] The present specification is also directed toward a tissue
ablation device, comprising: a liquid reservoir, wherein said
reservoir includes an outlet connector that can resist at least 1
atm of pressure for the attachment of a reusable cord; a heating
component comprising: a length of coiled tubing contained within a
heating element, wherein activation of said heating element causes
said coiled tubing to increase from a first temperature to a second
temperature and wherein said increase causes a conversion of liquid
within said coiled tubing to vapor; and an inlet connected to said
coiled tubing; an outlet connected to said coiled tubing; and at
least one pressure-resistant connection attached to the inlet
and/or outlet; a cord connecting the outlet of said reservoir to
the inlet of the heating component; a single use cord connecting a
pressure-resistant inlet port of a vapor based ablation device to
the outlet of said heating component.
[0046] In one embodiment, the liquid reservoir is integrated within
an operating room equipment generator. In one embodiment, the
liquid is water and the vapor is steam.
[0047] In one embodiment, the pressure-resistant connections are
luer lock connections. In one embodiment, the coiled tubing is
copper.
[0048] In one embodiment, the tissue ablation device further
comprises a foot pedal, wherein only when said foot pedal is
pressed, vapor is generated and passed into said single use cord.
In another embodiment, only when pressure is removed from said foot
pedal, vapor is generated and passed into said single use cord.
[0049] In another embodiment, the present specification discloses a
vapor ablation system used for supplying vapor to an ablation
device, comprising; a single use sterile fluid container with
attached compressible tubing used to connect the fluid source to a
heating unit in the handle of a vapor ablation catheter. The tubing
passes through a pump that delivers the fluid into the heating unit
at a predetermined speed. There is present a mechanism such as a
unidirectional valve between the fluid container and the heating
unit to prevent the backflow of vapor from the heating unit. The
heating unit is connected to the ablation catheter to deliver the
vapor from the heating unit to the ablation site. The flow of vapor
is controlled by a microprocessor. The microprocessor uses a
pre-programmed algorithm in an open-loop system or uses information
from one or more sensors incorporated in the ablation system in a
closed-loop system or both to control delivery of vapor.
[0050] In one embodiment, the handle of the ablation device is made
of a thermally insulating material to prevent thermal injury to the
operator. The heating unit is enclosed in the handle. The handle
locks into the channel of an endoscope after the catheter is passed
through the channel of the endoscope. The operator can than
manipulate the catheter by holding the insulated handle or by
manipulating the catheter proximal to the insulating handle.
[0051] The present specification is also directed toward a vapor
ablation system comprising: a container with a sterile liquid
therein; a pump in fluid communication with said container; a first
filter disposed between and in fluid communication with said
container and said pump; a heating component in fluid communication
with said pump; a valve disposed between and in fluid communication
with said pump and heating container; a catheter in fluid
communication with said heating component, said catheter comprising
at least one opening at its operational end; and, a microprocessor
in operable communication with said pump and said heating
component, wherein said microprocessor controls the pump to control
a flow rate of the liquid from said container, through said first
filter, through said pump, and into said heating component, wherein
said liquid is converted into vapor via the transfer of heat from
said heating component to said fluid, wherein said conversion of
said fluid into said vapor results is a volume expansion and a rise
in pressure where said rise in pressure forces said vapor into said
catheter and out said at least one opening, and wherein a
temperature of said heating component is controlled by said
microprocessor.
[0052] In one embodiment, the vapor ablation system further
comprises at least one sensor on said catheter, wherein information
obtained by said sensor is transmitted to said microprocessor, and
wherein said information is used by said microprocessor to regulate
said pump and said heating component and thereby regulate vapor
flow. In one embodiment, the at least one sensor includes one or
more of a temperature sensor, flow sensor, or pressure sensor.
[0053] In one embodiment, the vapor ablation system further
comprises a screw cap on said liquid container and a puncture
needle on said first filter, wherein said screw cap is punctured by
said puncture needle to provide fluid communication between said
container and said first filter.
[0054] In one embodiment, the liquid container and catheter are
disposable and configured for a single use.
[0055] In one embodiment, the fluid container, first filter, pump,
heating component, and catheter are connected by sterile tubing and
the connections between said pump and said heating component and
said heating component and said catheter are pressure
resistant.
[0056] The present specification is also directed toward a tissue
ablation system comprising: a catheter with a proximal end and a
distal end and a lumen therebetween, said catheter comprising: a
handle proximate the proximal end of said catheter and housing a
fluid heating chamber and a heating element enveloping said
chamber, a wire extending distally from said heating element and
leading to a controller; an insulating sheath extending and
covering the length of said catheter and disposed between said
handle and said heating element at said distal end of said
catheter; and, at least one opening proximate the distal end of
said catheter for the passage of vapor; and, a controller operably
connected to said heating element via said wire, wherein said
controller is capable of modulating energy supplied to said heating
element and further wherein said controller is capable of adjusting
a flow rate of liquid supplied to said catheter; wherein liquid is
supplied to said heating chamber and then converted to vapor within
said heating chamber by a transfer of heat from said heating
element to said chamber, wherein said conversion of said liquid to
vapor results in a volume expansion and a rise in pressure within
said catheter, and wherein said rise in pressure pushes said vapor
through said catheter and out said at least one opening.
[0057] In one embodiment, the tissue ablation system further
comprises a pressure resistant fitting attached to the fluid supply
and a one-way valve in said pressure resistant fitting to prevent a
backflow of vapor into the fluid supply.
[0058] In one embodiment, the tissue ablation system further
comprises at least one sensor on said catheter, wherein information
obtained by said sensor is transmitted to said microprocessor, and
wherein said information is used by said microprocessor to regulate
said pump and said heating component and thereby regulate vapor
flow.
[0059] In one embodiment, the tissue ablation system further
comprises a metal frame within said catheter, wherein said metal
frame is in thermal contact with said heating chamber and conducts
heat to said catheter lumen, thereby preventing condensation of
said vapor. In various embodiments, the metal frame comprises a
metal skeleton with outwardly extending fins at regularly spaced
intervals, a metal spiral, or a metal mesh and the metal frame
comprises at least one of copper, stainless steel, or another
ferric material.
[0060] In one embodiment, the heating element comprises a heating
block, wherein said heating block is supplied power by said
controller.
[0061] In various embodiments, the heating element uses one of
magnetic induction, microwave, high intensity focused ultrasound,
or infrared energy to heat said heating chamber and the fluid
therein.
[0062] The present specification also discloses an ablation
catheter for use with a hollow tissue or organ, comprising: a
distal end having at least one opening for the injection of a
conductive medium into said hollow tissue or organ and at least one
opening for the delivery of an ablative agent into said hollow
tissue or organ; a proximal end configured to receive said
conductive medium and said ablative agent from a source; and, a
shaft, having at least one lumen therewithin, between said distal
end and said proximal end.
[0063] In one embodiment, the ablation catheter for use with a
hollow tissue or organ further comprises at least one positioning
element for positioning said catheter proximate target tissue to be
ablated. In one embodiment, the ablation catheter further comprises
at least one occlusive element to occlude blood flow to said hollow
tissue or organ.
[0064] The present specification also discloses a method of
treating a disorder of a prostate, the method comprising:
introducing an ablation catheter into the prostate; and, delivering
an ablative agent into the prostate and ablating prostate tissue
without ablating the prostatic urethra. In one embodiment, the
ablative agent is vapor. In one embodiment, the catheter is
introduced transurethraly. In another embodiment, the catheter is
introduced transrectally.
[0065] The present specification also discloses an ablation
catheter for use in treating a disorder of the prostate, said
catheter comprising: one or more needles for piercing the prostatic
tissue and delivering an ablative agent into the prostate; and, one
or more positioning elements to position said needles at a
predefined distance in the prostate. In one embodiment, the
ablation catheter further comprises a mechanism to cool a prostatic
urethra or a rectal wall.
[0066] The present specification also discloses a method for
treating benign prostatic hyperplasia of a prostate of a patient
comprising the steps of: inserting a plurality of vapor delivery
needles through a urethral wall of the patient in a plurality of
locations into a prostate lobe; and, delivering water vapor through
the needles into the prostate at each location to ablate the
prostatic tissue.
[0067] The present specification also discloses a method of
providing ablation to a patient's endometrium comprising the steps
of: inserting an ablation catheter, said catheter comprising a
lumen and vapor delivery ports, through a cervix and a cervical
canal into the endometrial cavity; and, delivering an ablative
agent through said ablation catheter lumen and said delivery ports
and into the endometrial cavity to create endometrial ablation. In
one embodiment, the method of providing ablation to a patient's
endometrium further comprises the step of measuring at least one
dimension of the endometrial cavity and using said dimension to
determine the delivery of ablative agent. In one embodiment, the
method of providing ablation to a patient's endometrium further
comprises the step of using a positioning element to position said
catheter in the center of the endometrial cavity. In one
embodiment, the positioning element includes an expansion mechanism
in contact with endometrial tissue to move said endometrial tissue
surfaces away from the vapor delivery ports of the catheter. In one
embodiment, the method of providing ablation to a patient's
endometrium further comprises the step of using an occlusive
element to occlude the cervical os to prevent leakage of the
ablative agent through the os.
[0068] The present specification also discloses a method of
providing ablative therapy to a patient's endometrium comprising
the steps of: inserting a coaxial vapor ablation catheter,
comprising an inner catheter and an outer catheter, through the
cervical os and into the cervical canal to occlude the cervical
canal; advancing the inner catheter of the coaxial vapor ablation
catheter into the endometrial cavity; and, delivering vapor through
vapor delivery ports on the inner catheter into the endometrial
cavity to ablate the endometrial tissue. The inner catheter is
advanced to the fundus of the uterus, thus measuring the uterine
cavity length. The length of inner catheter needed, in-turn
determines the number of vapor delivery ports that are exposed to
deliver the ablative agent, thus controlling the amount of ablative
agent to be delivered.
[0069] The present specification also discloses a method for
hemorrhoid ablation comprising the steps of: inserting an ablation
device, said device comprising a port for engaging a hemorrhoid, at
least one port for delivery of an ablative agent, and a mechanism
to create suction, into a patient's anal canal; engaging the
targeted hemorrhoid by suctioning the hemorrhoid into the ablation
device; and, delivering the ablative agent to the hemorrhoid to
ablate the hemorrhoid.
[0070] The present specification also discloses a method of
ablating a tissue or organ, comprising the steps of: inserting a
catheter into said target tissue or organ; using the catheter to
remove contents of said target tissue or organ via suction; using
the catheter to replace said removed contents with a conductive
medium; introducing an ablative agent to said conductive medium,
and changing the temperature of said conductive medium to ablate
said tissue or organ.
[0071] The present specification also discloses a method of
ablating a hollow tissue or organ, comprising the steps of:
inserting a catheter into a hollow tissue or organ of a patient,
said catheter having a stent coupled to its distal end; advancing
said catheter and stent to target tissue; deploying said stent,
wherein said deployment involves releasing said stent from said
distal end of said catheter, further wherein said deployment causes
said stent to expand such that it comes into physical contact with,
and is held in place by, the internal surface of said hollow tissue
or organ; and, delivering ablative agent through said catheter and
into the lumen of said stent, wherein ablative energy from said
ablative agent is transferred from said lumen through said stent
and into the surrounding tissue to ablate said tissue.
[0072] The present specification also discloses a stent for use
with an ablation catheter, said stent comprising: a compressible,
cylindrical hollow body with a lumen therewithin, said body being
comprised of a thermally conductive material, wherein said body is
transformable between a first, compressed configuration for
delivery and a second, expanded configuration for deployment; one
or more openings for the passage of thermal energy from said lumen
of said stent to the exterior of said stent; one or more flaps
covering said openings to prevent the ingrowth of tissue
surrounding said stent into the lumen of said stent; and, at least
one coupling means to couple said stent to said ablation catheter
for delivery and/or retrieval.
[0073] The present specification also discloses an ablation
catheter assembly comprising: a catheter having an elongate body
with a lumen within, a proximal end, and a distal end; a first
inline chamber having an elongate body with a lumen within, a
proximal end, and a distal end, wherein said distal end of said
first inline chamber is connected to said proximal end of said
catheter and said lumen of said first inline chamber is in fluid
communication with said lumen of said catheter, further wherein
said first inline chamber is composed of a ferromagnetic or
thermally conducting material; a second inline chamber having an
elongate body with a lumen within, a proximal end, and a distal
end, wherein said distal end of said second inline chamber is
connected to said proximal end of said first inline chamber and
said lumen of said second inline chamber is in fluid communication
with said lumen of said first inline chamber, further wherein said
second inline chamber is configured to contain a fluid; an optional
one way valve positioned at the connection between said first
inline chamber and said second inline chamber, said valve allowing
flow of fluid from said second inline chamber into said first
inline chamber but not in the reverse direction; and, a piston
within and proximate said proximal end of said second inline
chamber; wherein said proximal end of said second inline chamber is
connected to an external pump and said pump engages said piston to
push a fluid from said second inline chamber into said first inline
chamber where an external heating element heats said first inline
chamber and the transfer of said heat to said fluid causes
vaporization of said fluid, further wherein said vaporized fluid
passes through said elongate body and out said distal end of said
catheter.
[0074] Optionally, in one embodiment, the ablation catheter
assembly further comprises a thermally insulated handle on said
catheter body. In one embodiment, the pump is a syringe pump. In
one embodiment, the pump is controlled by a microprocessor to
deliver ablative vapor at a predetermined rate. Optionally, a
peristaltic pump or any other pump known in the field can be used
to push fluid from the second inline chamber to the first inline
chamber at a rate that is controllable by a microprocessor. In one
embodiment, the ablation catheter assembly further comprises at
least one sensor on said catheter, wherein information from said
sensor is relayed to said microprocessor and the delivery rate of
ablative vapor is based upon said information.
[0075] In one embodiment, the heating element is any one of a
resistive heater, an RF heater, a microwave heater and an
electromagnetic heater. In one embodiment, the fluid is water. In
one embodiment, the first inline chamber comprises a plurality of
channels within to increase the contact surface area of said fluid
with said first inline chamber. In various embodiments, the
channels comprise any one of metal tubes, metal beads, and metal
filings.
[0076] In one embodiment, the elongate body of said catheter
includes an outer surface and an inner surface and said inner
surface includes a groove pattern to decrease the resistance to
flow of said fluid within said catheter.
[0077] Optionally, in one embodiment, the catheter comprises a
first inner wall and a second outer wall and an insulating layer
between said first wall and said second wall. In one embodiment,
said first inner wall and said second outer wall are connected by a
plurality of spokes. In one embodiment, the insulating layer is
filled with air. In another embodiment, the insulating layer is
filled with a fluid. In another embodiment, the insulating layer is
made of any thermally insulating material.
[0078] The present specification also discloses a system for
heating a fluid, said system comprising: a chamber for containing
said fluid, said chamber defining an enclosed three dimensional
space and having a proximal end and a distal end, wherein said
proximal end includes an inlet port for delivery of said fluid and
said distal end includes an outlet port, further wherein said
chamber is composed of a ferromagnetic material; and, an induction
heating element positioned around said chamber, said induction
heating element capable of receiving an alternating current;
wherein, when an alternating current is supplied to said induction
heating element, a magnetic field is created in the area
surrounding said chamber and said magnetic field induces electric
current flow within the ferromagnetic material of said chamber,
further wherein said electric current flow results in the heating
of said chamber and said heat is transferred to said fluid,
converting said fluid into vapor which exits said chamber through
said outlet port.
[0079] In various embodiments, the ferromagnetic material comprises
any one of iron, stainless steel, and copper. In various
embodiments, the ferromagnetic material is a curie material with a
curie temperature between 60.degree. C. and 250.degree. C.
[0080] In one embodiment, the induction heating element comprises a
metal wire coil looped about said chamber. In one embodiment, the
coil is looped about a length of said chamber such that said coil
is in physical contact with said chamber. In other embodiments, the
coil is looped about a length of said chamber spaced away from said
chamber with a layer of air or insulating material between said
coil and said chamber.
[0081] The present specification also discloses a method for
heating a fluid, said method comprising the steps of: providing a
chamber for containing said fluid, said chamber defining an
enclosed three dimensional space and having a proximal end and a
distal end, wherein said proximal end includes an inlet port for
delivery of said fluid and said distal end includes an outlet port,
further wherein said chamber is composed of a ferromagnetic
material; surrounding said chamber with an induction heating
element; filling said container with said fluid; providing an
alternating current to said induction heating element such that a
magnetic field is created in the area surrounding said chamber and
said magnetic field induces electric current flow within the
ferromagnetic material of said chamber, further wherein said
electric current flow results in the heating of said chamber and
said heat is transferred to said fluid, converting said fluid into
vapor which exits said chamber through said outlet port.
[0082] The aforementioned and other embodiments of the present
invention shall be described in greater depth in the drawings and
detailed description provided below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0083] These and other features and advantages of the present
invention will be further appreciated, as they become better
understood by reference to the detailed description when considered
in connection with the accompanying drawings, wherein:
[0084] FIG. 1 illustrates an ablation device, in accordance with an
embodiment of the present specification;
[0085] FIG. 2A illustrates a longitudinal section of an ablation
device with ports distributed thereon;
[0086] FIG. 2B illustrates a cross section of a port on the
ablation device, in accordance with an embodiment of the present
specification;
[0087] FIG. 2C illustrates a cross section of a port on the
ablation device, in accordance with another embodiment of the
present specification;
[0088] FIG. 2D illustrates a catheter of the ablation device, in
accordance with an embodiment of the present specification;
[0089] FIG. 2E illustrates a catheter of the ablation device, in
accordance with another embodiment of the present
specification;
[0090] FIG. 2F illustrates a catheter of the ablation device, in
accordance with yet another embodiment of the present
specification;
[0091] FIG. 2G is a flow chart listing the steps involved in a
hollow tissue or organ ablation process using an ablation device,
in accordance with one embodiment of the present specification;
[0092] FIG. 2H illustrates an ablation device in the form of a
catheter extending from a conventional snare handle, in accordance
with an embodiment of the present specification;
[0093] FIG. 2I illustrates a cross section of an ablation device in
the form of a catheter extending from a conventional snare handle
with a pre-attached cord, in accordance with another embodiment of
the present specification;
[0094] FIG. 2J illustrates an ablation device in the form of a
catheter extending from a conventional esophageal probe, in
accordance with an embodiment of the present specification;
[0095] FIG. 3A illustrates the ablation device placed in an upper
gastrointestinal tract with Barrett's esophagus to selectively
ablate the Barrett's tissue, in accordance with an embodiment of
the present specification;
[0096] FIG. 3B illustrates the ablation device placed in an upper
gastrointestinal tract with Barrett's esophagus to selectively
ablate the Barrett's tissue, in accordance with another embodiment
of the present specification;
[0097] FIG. 3C is a flowchart illustrating the basic procedural
steps for using the ablation device, in accordance with an
embodiment of the present specification;
[0098] FIG. 4A illustrates the ablation device placed in a colon to
ablate a flat colon polyp, in accordance with an embodiment of the
present specification;
[0099] FIG. 4B illustrates the ablation device placed in a colon to
ablate a flat colon polyp, in accordance with another embodiment of
the present specification;
[0100] FIG. 5A illustrates the ablation device with a coaxial
catheter design, in accordance with an embodiment of the present
specification;
[0101] FIG. 5B illustrates a partially deployed positioning device,
in accordance with an embodiment of the present specification;
[0102] FIG. 5C illustrates a completely deployed positioning
device, in accordance with an embodiment of the present
specification;
[0103] FIG. 5D illustrates the ablation device with a conical
positioning element, in accordance with an embodiment of the
present specification;
[0104] FIG. 5E illustrates the ablation device with a disc shaped
positioning element, in accordance with an embodiment of the
present specification;
[0105] FIG. 6 illustrates an upper gastrointestinal tract with a
bleeding vascular lesion being treated by the ablation device, in
accordance with an embodiment of the present specification;
[0106] FIG. 7A illustrates endometrial ablation being performed in
a female uterus by using the ablation device, in accordance with an
embodiment of the present specification;
[0107] FIG. 7B is an illustration of a coaxial catheter used in
endometrial tissue ablation, in accordance with one embodiment of
the present specification;
[0108] FIG. 7C is a flow chart listing the steps involved in an
endometrial tissue ablation process using a coaxial ablation
catheter, in accordance with one embodiment of the present
specification;
[0109] FIG. 8 illustrates sinus ablation being performed in a nasal
passage by using the ablation device, in accordance with an
embodiment of the present specification;
[0110] FIG. 9 illustrates bronchial and bullous ablation being
performed in a pulmonary system by using the ablation device, in
accordance with an embodiment of the present specification;
[0111] FIG. 10A illustrates prostate ablation being performed on an
enlarged prostrate in a male urinary system by using the device, in
accordance with an embodiment of the present specification;
[0112] FIG. 10B is an illustration of transurethral prostate
ablation being performed on an enlarged prostrate in a male urinary
system using an ablation device, in accordance with one embodiment
of the present specification;
[0113] FIG. 10C is an illustration of transurethral prostate
ablation being performed on an enlarged prostrate in a male urinary
system using an ablation device, in accordance with another
embodiment of the present specification;
[0114] FIG. 10D is a flow chart listing the steps involved in a
transurethral enlarged prostate ablation process using an ablation
catheter, in accordance with one embodiment of the present
specification;
[0115] FIG. 10E is an illustration of transrectal prostate ablation
being performed on an enlarged prostrate in a male urinary system
using an ablation device, in accordance with one embodiment of the
present specification;
[0116] FIG. 10F is an illustration of transrectal prostate ablation
being performed on an enlarged prostrate in a male urinary system
using a coaxial ablation device having a positioning element, in
accordance with another embodiment of the present
specification;
[0117] FIG. 10G is a flow chart listing the steps involved in a
transrectal enlarged prostate ablation process using an ablation
catheter, in accordance with one embodiment of the present
specification;
[0118] FIG. 10H is an illustration of an ablation catheter for
permanent implantation in the body to deliver repeat ablation, in
accordance with one embodiment of the present specification;
[0119] FIG. 10I is an illustration of a trocar used to place the
ablation catheter of FIG. 10H in the body, in accordance with one
embodiment of the present specification;
[0120] FIG. 10J is an illustration of the catheter of FIG. 10H and
the trocar of FIG. 10I assembled for placement of the catheter into
tissue targeted for ablation in the human body, in accordance with
one embodiment of the present specification;
[0121] FIG. 11 illustrates fibroid ablation being performed in a
female uterus by using the ablation device, in accordance with an
embodiment of the present specification;
[0122] FIG. 12A illustrates a blood vessel ablation being performed
by an ablation device, in accordance with one embodiment of the
present specification;
[0123] FIG. 12B illustrates a blood vessel ablation being performed
by an ablation device, in accordance with another embodiment of the
present specification;
[0124] FIG. 12C is a flow chart listing the steps involved in a
blood vessel ablation process using an ablation catheter, in
accordance with one embodiment of the present specification;
[0125] FIG. 13A illustrates a cyst ablation being performed by an
ablation device, in accordance with one embodiment of the present
specification;
[0126] FIG. 13B is a flow chart listing the steps involved in a
cyst ablation process using an ablation catheter, in accordance
with one embodiment of the present specification;
[0127] FIG. 14 is a flow chart listing the steps involved in a
tumor ablation process using an ablation catheter, in accordance
with one embodiment of the present specification;
[0128] FIG. 15A illustrates a non-endoscopic device used for
internal hemorrhoid ablation, in accordance with one embodiment of
the present specification;
[0129] FIG. 15B is a flow chart listing the steps involved in an
internal hemorrhoid ablation process using an ablation device, in
accordance with one embodiment of the present specification;
[0130] FIG. 16A illustrates an endoscopic device used for internal
hemorrhoid ablation, in accordance with one embodiment of the
present specification;
[0131] FIG. 16B is a flow chart listing the steps involved in an
internal hemorrhoid ablation process using an endoscopic ablation
device, in accordance with one embodiment of the present
specification;
[0132] FIG. 17A illustrates a stent used to provide localized
ablation to a target tissue, in accordance with one embodiment of
the present specification;
[0133] FIG. 17B illustrates a catheter used to deploy, and provide
an ablative agent to, the stent of FIG. 17A;
[0134] FIG. 17C illustrates the stent of FIG. 17A working in
conjunction with the catheter of FIG. 17B;
[0135] FIG. 17D illustrates the stent of FIG. 17A and the catheter
of FIG. 17B positioned in a bile duct obstructed by a pancreatic
tumor;
[0136] FIG. 17E is a flow chart listing the steps involved in a
hollow tissue or organ ablation process using an ablation stent and
catheter, in accordance with one embodiment of the present
specification;
[0137] FIG. 18 illustrates a vapor delivery system using an RF
heater for supplying vapor to the ablation device, in accordance
with an embodiment of the present specification;
[0138] FIG. 19 illustrates a vapor delivery system using a
resistive heater for supplying vapor to the ablation device, in
accordance with an embodiment of the present specification;
[0139] FIG. 20 illustrates a vapor delivery system using a heating
coil for supplying vapor to the ablation device, in accordance with
an embodiment of the present specification;
[0140] FIG. 21 illustrates the heating component and coiled tubing
of the heating coil vapor delivery system of FIG. 20, in accordance
with an embodiment of the present specification;
[0141] FIG. 22A illustrates the unassembled interface connection
between the ablation device and the single use cord of the heating
coil vapor delivery system of FIG. 20, in accordance with an
embodiment of the present specification;
[0142] FIG. 22B illustrates the assembled interface connection
between the ablation device and the single use cord of the heating
coil vapor delivery system of FIG. 20, in accordance with an
embodiment of the present specification;
[0143] FIG. 23 illustrates a vapor ablation system using a heater
or heat exchange unit for supplying vapor to the ablation device,
in accordance with another embodiment of the present
specification;
[0144] FIG. 24 illustrates the fluid container, filter member, and
pump of the vapor ablation system of FIG. 23;
[0145] FIG. 25 illustrates a first view of the fluid container,
filter member, pump, heater or heat exchange unit, and
microcontroller of the vapor ablation system of FIG. 23;
[0146] FIG. 26 illustrates a second view of the fluid container,
filter member, pump, heater or heat exchange unit, and
microcontroller of the vapor ablation system of FIG. 23;
[0147] FIG. 27 illustrates the unassembled filter member of the
vapor ablation system of FIG. 23, depicting the filter positioned
within;
[0148] FIG. 28 illustrates one embodiment of the microcontroller of
the vapor ablation system of FIG. 23;
[0149] FIG. 29 illustrates one embodiment of a catheter assembly
for use with the vapor ablation system of FIG. 23;
[0150] FIG. 30 illustrates one embodiment of a heat exchange unit
for use with the vapor ablation system of FIG. 23;
[0151] FIG. 31A illustrates another embodiment of a heat exchange
unit for use with the vapor ablation system of the present
specification;
[0152] FIG. 31B illustrates another embodiment of a heat exchange
unit for use with the vapor ablation system of the present
specification;
[0153] FIG. 32A illustrates the use of induction heating to heat a
chamber;
[0154] FIG. 32B is a flow chart listing the steps involved in using
induction heating to heat a chamber;
[0155] FIG. 33A illustrates one embodiment of a coil used with
induction heating in the vapor ablation system of the present
specification;
[0156] FIG. 33B illustrates one embodiment of a catheter handle
used with induction heating in the vapor ablation system of the
present specification;
[0157] FIG. 34A is a front view cross sectional diagram
illustrating one embodiment of a catheter used with induction
heating in the vapor ablation system of the present
specification;
[0158] FIG. 34B is a longitudinal view cross sectional diagram
illustrating one embodiment of a catheter used with induction
heating in the vapor ablation system of the present
specification;
[0159] FIG. 34C is a longitudinal view cross sectional diagram
illustrating another embodiment of a catheter with a metal spiral
used with induction heating in the vapor ablation system of the
present specification;
[0160] FIG. 34D is a longitudinal view cross sectional diagram
illustrating another embodiment of a catheter with a mesh used with
induction heating in the vapor ablation system of the present
specification;
[0161] FIG. 35 illustrates one embodiment of a heating unit using
microwaves to convert fluid to vapor in the vapor ablation system
of the present specification;
[0162] FIG. 36A illustrates a catheter assembly having an inline
chamber for heat transfer in accordance with one embodiment of the
present specification;
[0163] FIG. 36B illustrates the catheter assembly of FIG. 35A
including an optional handle;
[0164] FIG. 36C illustrates the catheter assembly of FIG. 36B
connected to a generator having a heating element and a pump, in
accordance with one embodiment of the present specification;
[0165] FIG. 37A illustrates a heating chamber packed with metal
tubes in accordance with one embodiment of the present
specification;
[0166] FIG. 37B illustrates a heating chamber packed with metal
beads in accordance with one embodiment of the present
specification;
[0167] FIG. 37C illustrates a heating chamber packed with metal
filings in accordance with one embodiment of the present
specification;
[0168] FIG. 38A illustrates a cross-sectional view of one
embodiment of a catheter having an internal groove to decrease flow
resistance;
[0169] FIG. 38B illustrates an on-end view of one embodiment of a
catheter having an internal groove to decrease flow resistance;
[0170] FIG. 39A illustrates a cross-sectional view of a double
layered catheter in accordance with one embodiment of the present
specification; and,
[0171] FIG. 39B illustrates a cross-sectional view of a double
layered catheter in accordance with another embodiment of the
present specification.
DETAILED DESCRIPTION
[0172] The present specification is directed toward an ablation
device comprising a catheter with one or more centering or
positioning attachments at one or more ends of the catheter to
affix the catheter and its infusion port at a fixed distance from
the ablative tissue which is not affected by the movements of the
organ. The arrangement of one or more spray ports allows for
uniform spray of the ablative agent producing a uniform ablation of
a large area, such as encountered in Barrett's esophagus or for
endometrial ablation. The flow of ablative agent is controlled by
the microprocessor and depends upon one or more of the length or
area of tissue to be ablated, type and depth of tissue to be
ablated, and distance of the infusion port from or in the tissue to
be ablated.
[0173] The present specification is also directed toward a device
to be used in conjunction with a tissue ablation system,
comprising: a handle with a pressure-resistant port on its distal
end, a flow channel through which an ablative agent can travel, and
one or more connection ports on its proximal end for the inlet of
said ablative agent and for an RF feed or an electrical feed; an
insulated catheter that attaches to said pressure-resistant port of
said handle, containing a shaft through which an ablative agent can
travel and one or more ports along its length for the release of
said ablative agent; and, one or more positioning elements attached
to said catheter shaft at one or more separate positions, wherein
said positioning element(s) is configured to position said catheter
at a predefined distance from or in the tissue to be ablated.
[0174] In one embodiment, the handle has one pressure-resistant
port for the attachment of both an ablative agent inlet and an RF
feed. In another embodiment, the handle has one separate
pressure-resistant port for the attachment of an ablative agent
inlet and one separate port for the attachment of an RF feed or an
electrical feed.
[0175] The present specification is also directed toward a device
to be used in conjunction with a tissue ablation system,
comprising: a handle with a pressure-resistant port on its distal
end, a flow channel passing through said handle which is continuous
with a pre-attached cord through which an ablative agent can
travel, and a connection port on its proximal end for an RF feed or
an electrical feed; an insulated catheter that attaches to said
pressure-resistant port of said handle, containing a shaft through
which an ablative agent can travel and one or more ports along its
length for the release of said ablative agent; and, one or more
positioning elements attached to said catheter shaft at one or more
separate positions, wherein said positioning element(s) is
configured to position said catheter at a predefined distance from
or in the tissue to be ablated. In one embodiment, the distal end
of said catheter is designed to puncture the target tissue to
deliver ablative agent to the correct depth and location.
[0176] The present specification is also directed toward a device
to be used in conjunction with a tissue ablation system,
comprising: an esophageal probe with a pressure-resistant port on
its distal end, a flow channel through which an ablative agent can
travel, and one or more connection ports on its proximal end for
the inlet of said ablative agent and for an RF feed; an insulated
catheter that attaches to said pressure-resistant port of said
esophageal probe, containing a shaft through which an ablative
agent can travel and one or more ports along its length for the
release of said ablative agent; and, one or more inflatable
positioning balloons at either end of said catheter positioned
beyond said one or more ports, wherein said positioning balloons
are configured to position said catheter at a predefined distance
from the tissue to be ablated.
[0177] In one embodiment, the catheter is dual lumen, wherein a
first lumen facilitates the transfer of ablative agent and a second
lumen contains an electrode for RF ablation.
[0178] In one embodiment, the catheter has differential insulation
along its length.
[0179] The present specification is also directed toward a vapor
delivery system used for supplying vapor to an ablation device,
comprising: a liquid reservoir, wherein said reservoir includes a
pressure-resistant outlet connector for the attachment of a
reusable cord; a reusable cord connecting the outlet of said
reservoir to the inlet of a heating component; a powered heating
component containing a length of coiled tubing within for the
conversion of liquid to vapor and pressure-resistant connections on
both the inlet and outlet ends of said heating component; and, a
single use cord connecting a pressure-resistant inlet port of a
vapor based ablation device to the outlet of said heating
component.
[0180] In one embodiment, the liquid reservoir is integrated within
an operating room equipment generator.
[0181] In one embodiment, the liquid is water and resultant said
vapor is steam.
[0182] In one embodiment, the pressure-resistant connections are of
a luer lock type.
[0183] In one embodiment, the coiled tubing is copper.
[0184] In one embodiment, the vapor delivery system used for
supplying vapor to an ablation device further comprises a foot
pedal used by the operator to deliver more vapor to the ablation
device.
[0185] The present specification is also directed toward a device
and a method for ablating a hollow tissue or organ by replacing the
natural contents of the tissue or organ with a conductive medium
and then delivering an ablative agent to the conductive medium to
ablate the tissue or organ.
[0186] The present specification is also directed toward a device
and method for ablating a blood vessel consisting of replacing the
blood in the targeted vessel with a conductive medium and then
delivering an ablative agent to the conductive medium to ablate the
vessel. In one embodiment, the device and method further comprise a
means or step for stopping the flood of blood into the target
vessel. In one embodiment, blood flow is occluded by the
application of a tourniquet proximal to the target vessel. In
another embodiment, blood flow is occluded by the application of at
least one intraluminal occlusive element. In one embodiment, the at
least one intraluminal occlusive element includes at least one
unidirectional valve. In one embodiment, the intraluminal occlusive
element is used to position the source or port delivering the
ablative agent in the vessel.
[0187] The present specification is also directed toward a device
and a method for ablating a cyst by inserting a catheter into the
cyst, replacing a portion of the contents of the cyst with a
conductive medium, adding an ablative agent to the conductive
medium, and conducting ablative energy to the cyst wall through the
medium to ablate the cyst.
[0188] The present specification is also directed toward a device
and a method for ablating a tumor by inserting a catheter into the
tumor, replacing a portion of the contents of the tumor with a
conductive medium, adding an ablative agent to the conductive
medium, and conducting ablative energy to the tumor wall through
the medium to ablate the tumor.
[0189] In various embodiments, any one of the devices described
above comprises a catheter and includes at least one port for
delivering the conductive medium and at least one separate port for
delivering the ablative agent. In another embodiment, the device
comprises a catheter and includes at least one port for delivering
both the conductive medium and the ablative agent. Optionally, in
one embodiment, the device further includes at least one port for
removing the contents of the hollow organ or tissue or for removing
the conductive medium. In various embodiments, the at least one
port for removing contents or conductive medium is the same port
for delivering the conductive medium and/or ablative agent or is a
separate port. In one embodiment, the ablative agent is a thermal
agent, such as steam. In another embodiment, the ablative agent is
a cryogen, such as liquid nitrogen.
[0190] Optionally, in one embodiment, sensors are included in the
device to measure and control the flow of the ablative agent. In
one embodiment, conductive medium is water. In another embodiment,
the conductive medium is saline.
[0191] In various embodiments, any one of the devices described
above comprises a coaxial catheter having an outer, insulating
sheath and an inner tubular member for delivery of the conductive
medium and the ablative agent.
[0192] Optionally, in various embodiments, any one of the devices
described above includes echogenic elements to assist with the
placement of the device into the target tissue under ultrasonic
guidance. Optionally, in various embodiments, any one of the
devices described above includes radio-opaque elements to assist
with the placement of the device into the target tissue under
radiologic guidance.
[0193] The present specification is also directed toward a system
and method of internal hemorrhoid ablation by inserting a hollow,
tubular device into a patient's rectum, applying suction to the
device to draw the target hemorrhoid tissue into a slot in the
device, and delivering an ablative agent, such as steam, through a
port in the device to ablate the hemorrhoid. In one embodiment, the
system includes a device composed of a thermally insulated material
to avoid transfer of vapor heat to surrounding rectal mucosa. In
another embodiment, the system has a mechanism for puncturing the
mucosa to deliver the ablative agent directly into the submucosa
closer to the hemorrhoid. In another embodiment, the system has a
mechanism for cooling the mucosa so as to reduce the ablative
damage to the mucosa.
[0194] The present specification is also directed toward a system
and method of internal hemorrhoid ablation by inserting a hollow,
tubular device into a patient's rectum, applying suction to the
device to draw the target hemorrhoid tissue into a slot in the
device, inserting a needle through the slot and into the rectal
submucosa or the wall of the hemorrhoid vessel, and delivering an
ablative agent through the needle to ablate the hemorrhoid.
[0195] The present specification is also directed toward a device
and method for endometrial treatment by inserting a coaxial
catheter comprising an internal catheter and an external catheter
into the cervix, wherein the external catheter engages the cervix
and the internal catheter extends into the uterus. The internal
catheter continues until it reaches the fundus of the uterus, at
which point the depth of insertion of the internal catheter is used
to measure the depth of the uterine cavity. An ablative agent, such
as steam, is then delivered via the at least one port on the
internal catheter to provide treatment to the endometrium.
Optionally, in various embodiments, the catheter includes pressure
sensors and/or temperature sensors to measure the intrauterine
pressure or temperature. Optionally, in one embodiment, the
external catheter further comprises a plurality of fins which
engage the cervix and prevent the escape of ablative agent. In one
embodiment, the fins are composed of silicon. Optionally in one
embodiment, the coaxial catheter further includes a locking
mechanism between the external catheter and internal catheter that,
when engaged, prevents the escape of ablative agent. In one
embodiment, the locking mechanism is of a luer lock type.
Optionally, the flow of ablative agent is controlled by the number
of open ports which in turn is controlled by the length of the
exposed internal catheter.
[0196] The present specification is also directed toward device and
method for tissue ablation comprising a stent covered by a membrane
that conducts an ablative agent, such as steam, or ablative energy
from inside the stent lumen to the external surface of the stent
for ablation of surrounding tissue. In one embodiment, the stent
has a pre-deployment shape and a post-deployment shape. The
pre-deployment shape is configured to assist with placement of the
stent. In one embodiment, the membrane is composed of a thermally
conductive material. In one embodiment, the membrane includes a
plurality of openings that allow for the passage of ablative agent
or energy from the stent lumen to the tissue surrounding the stent.
In one embodiment, the stent is used to treat obstruction in a
hollow organ. In one embodiment, the membrane is made of a
thermally conductive material that allows for transfer of energy
from the inside of the stent to the outside of the stent into the
surrounding tissue.
[0197] In one embodiment, a catheter is used to deliver the
ablative agent to the stent. The catheter includes at least one
port at its distal end for the delivery of ablative agent into the
lumen of the stent. In one embodiment, the catheter includes one or
more positioning elements configured to fix the catheter at a
predefined distance from the stent. The positioning element(s) also
acts as an occlusive member to prevent the flow of ablative agent
out of the ends of the stent. In one embodiment, the catheter is
composed of a thermally insulating material. Optionally, in various
embodiments, the catheter includes additional lumens for the
passage of a guidewire or radiologic contrast material.
[0198] The present specification is also directed toward a device
and method for transrectal prostate ablation. An endoscope is
inserted into the rectum for visualization of the prostate. In one
embodiment, the endoscope is an echoendoscope. In another
embodiment, the visualization is achieved via transrectal
ultrasound. A catheter with a needle tip is passed transrectally
into the prostate and an ablative agent, such as vapor, is
delivered through the needle tip and into the prostatic tissue. In
one embodiment, the needle tip is an echotip or sonolucent tip that
can be detected by the echoendoscope to aid in placement within the
prostatic tissue. In one embodiment, the catheter and needle tip
are composed of a thermally insulating material. Optionally, in one
embodiment, an additional catheter is placed in the patient's
urethra to insert fluid to cool the prostatic urethra. In one
embodiment, the cooling fluid has a temperature of less than
37.degree. C. Optionally, in one embodiment, the catheter further
comprises a positioning element which positions the needle tip at a
predetermined depth in the prostatic tissue. In one embodiment, the
positioning element is a compressible disc.
[0199] The present specification is also directed toward an
ablation catheter assembly comprising a catheter body, a first
inline chamber for heating an ablative agent, and a second inline
chamber for storing said ablative agent. A pump drives a piston
located within the second inline chamber to push a fluid through a
one-way valve and into the first inline chamber. A heating element
heats the first inline chamber, converting the fluid from a liquid
into a vapor. The vapor then travels through the catheter and is
delivered to the target tissue site for ablation. In various
embodiments, the first chamber is composed of a ferromagnetic or
thermally conducting material. In one embodiment, the pump is
controlled by a microprocessor to deliver ablative agent at a
predetermined rate. In one embodiment, sensors in the catheter
provide information microprocessor to control the delivery rate. In
one embodiment, the catheter includes an insulated handle to allow
for safe manipulation of the catheter assembly by an operator. In
various embodiments, the heating element is a resistive heater, RF
heater, microwave heater, or electromagnetic heater.
[0200] In various embodiments, the first inline chamber comprises a
plurality of channels within to increase the contact surface area
of the ablative agent with the walls of the chamber to provide for
more efficient heating of said agent. In various embodiments, the
channels comprise metal tubes, metal beads, or metal filings. In
one embodiment, the inner surface of the catheter includes a groove
pattern to reduce the resistance to flow of the ablative agent
within the catheter. In one embodiment, the catheter comprises two
walls, an inner wall and an outer wall, with a thin insulating
layer in between, to insulate the catheter and prevent thermal
trauma to an operator from the heated ablative agent within said
catheter.
[0201] In various embodiments, the ablation devices and catheters
described in the present specification are used in conjunction with
any one or more of the heating systems described in U.S. patent
application Ser. No. 13/486,980, entitled "Method and Apparatus for
Tissue Ablation", filed on Jun. 1, 2012 and assigned to the
applicant of the present invention, which is herein incorporated by
reference in its entirety.
[0202] "Treat," "treatment," and variations thereof refer to any
reduction in the extent, frequency, or severity of one or more
symptoms or signs associated with a condition.
[0203] "Duration" and variations thereof refer to the time course
of a prescribed treatment, from initiation to conclusion, whether
the treatment is concluded because the condition is resolved or the
treatment is suspended for any reason. Over the duration of
treatment, a plurality of treatment periods may be prescribed
during which one or more prescribed stimuli are administered to the
subject.
[0204] "Period" refers to the time over which a "dose" of
stimulation is administered to a subject as part of the prescribed
treatment plan.
[0205] The term "and/or" means one or all of the listed elements or
a combination of any two or more of the listed elements.
[0206] The terms "comprises" and variations thereof do not have a
limiting meaning where these terms appear in the description and
claims.
[0207] Unless otherwise specified, "a," "an," "the," "one or more,"
and "at least one" are used interchangeably and mean one or more
than one.
[0208] For any method disclosed herein that includes discrete
steps, the steps may be conducted in any feasible order. And, as
appropriate, any combination of two or more steps may be conducted
simultaneously.
[0209] Also herein, the recitations of numerical ranges by
endpoints include all numbers subsumed within that range (e.g., 1
to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). Unless
otherwise indicated, all numbers expressing quantities of
components, molecular weights, and so forth used in the
specification and claims are to be understood as being modified in
all instances by the term "about." Accordingly, unless otherwise
indicated to the contrary, the numerical parameters set forth in
the specification and claims are approximations that may vary
depending upon the desired properties sought to be obtained by the
present specification. At the very least, and not as an attempt to
limit the doctrine of equivalents to the scope of the claims, each
numerical parameter should at least be construed in light of the
number of reported significant digits and by applying ordinary
rounding techniques.
[0210] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the specification are
approximations, the numerical values set forth in the specific
examples are reported as precisely as possible. All numerical
values, however, inherently contain a range necessarily resulting
from the standard deviation found in their respective testing
measurements.
[0211] Ablative agents such as steam, heated gas or cryogens, such
as, but not limited to, liquid nitrogen are inexpensive and readily
available and are directed via the infusion port onto the tissue,
held at a fixed and consistent distance, targeted for ablation.
This allows for uniform distribution of the ablative agent on the
targeted tissue. The flow of the ablative agent is controlled by a
microprocessor according to a predetermined method based on the
characteristic of the tissue to be ablated, required depth of
ablation, and distance of the port from the tissue. The
microprocessor may use temperature, pressure or other sensing data
to control the flow of the ablative agent. In addition, one or more
suction ports are provided to suction the ablation agent from the
vicinity of the targeted tissue. The targeted segment can be
treated by a continuous infusion of the ablative agent or via
cycles of infusion and removal of the ablative agent as determined
and controlled by the microprocessor.
[0212] It should be appreciated that the devices and embodiments
described herein are implemented in concert with a controller that
comprises a microprocessor executing control instructions. The
controller can be in the form of any computing device, including
desktop, laptop, and mobile device, and can communicate control
signals to the ablation devices in wired or wireless form.
[0213] The present invention is directed towards multiple
embodiments. The following disclosure is provided in order to
enable a person having ordinary skill in the art to practice the
invention. Language used in this specification should not be
interpreted as a general disavowal of any one specific embodiment
or used to limit the claims beyond the meaning of the terms used
therein. The general principles defined herein may be applied to
other embodiments and applications without departing from the
spirit and scope of the invention. Also, the terminology and
phraseology used is for the purpose of describing exemplary
embodiments and should not be considered limiting. Thus, the
present invention is to be accorded the widest scope encompassing
numerous alternatives, modifications and equivalents consistent
with the principles and features disclosed. For purpose of clarity,
details relating to technical material that is known in the
technical fields related to the invention have not been described
in detail so as not to unnecessarily obscure the present
invention.
[0214] FIG. 1 illustrates an ablation device, in accordance with an
embodiment of the present specification. The ablation device
comprises a catheter 10 having a distal centering or positioning
attachment which is an inflatable balloon 11. The catheter 10 is
made of or covered with an insulated material to prevent the escape
of ablative energy from the catheter body. The ablation device
comprises one or more infusion ports 12 for the infusion of
ablative agent and one or more suction ports 13 for the removal of
ablative agent. In one embodiment, the infusion port 12 and suction
port 13 are the same. In one embodiment, the infusion ports 12 can
direct the ablative agent at different angles. Ablative agent is
stored in a reservoir 14 connected to the catheter 10. Delivery of
the ablative agent is controlled by a microprocessor 15 and
initiation of the treatment is controlled by a treating physician
using an input device, such as a foot-paddle 16. In other
embodiments, the input device could be a voice recognition system
(that is responsive to commands such as "start", "more", "less",
etc.), a mouse, a switch, footpad, or any other input device known
to persons of ordinary skill in the art. In one embodiment,
microprocessor 15 translates signals from the input device, such as
pressure being placed on the foot-paddle or vocal commands to
provide "more" or "less" ablative agent, into control signals that
determine whether more or less ablative agent is dispensed.
Optional sensor 17 monitors changes in an ablative tissue or its
vicinity to guide flow of ablative agent. In one embodiment,
optional sensor 17 also includes a temperature sensor. Optional
infrared, electromagnetic, acoustic or radiofrequency energy
emitters and sensors 18 measure the dimensions of the hollow
organ.
[0215] In one embodiment, a user interface included with the
microprocessor 15 allows a physician to define device, organ, and
condition which in turn creates default settings for temperature,
cycling, volume (sounds), and standard RF settings. In one
embodiment, these defaults can be further modified by the
physician. The user interface also includes standard displays of
all key variables, along with warnings if values exceed or go below
certain levels.
[0216] The ablation device also includes safety mechanisms to
prevent users from being burned while manipulating the catheter,
including insulation, and optionally, cool air flush, cool water
flush, and alarms/tones to indicate start and stop of
treatment.
[0217] In one embodiment, the inflatable balloon has a diameter of
between 1 mm and 10 cm. In one embodiment, the inflatable balloon
is separated from the ports by a distance of 1 mm to 10 cm. In one
embodiment, the size of the port openings is between 1 .mu.m and 1
cm. It should be appreciated that the inflatable balloon is used to
fix the device and therefore is configured to not contact the
ablated area. The inflatable balloon can be any shape that contacts
the hollow organ at 3 or more points. One of ordinary skill in the
art will recognize that, using triangulation, one can calculate the
distance of the catheter from the lesion. Alternatively, the
infrared, electromagnetic, acoustic or radiofrequency energy
emitters and sensors 18 can measure the dimensions of the hollow
organ. The infrared, electromagnetic, acoustic or radiofrequency
energy is emitted from the emitter 18 and is reflected back from
the tissue to the detector in the emitter 18. The reflected data
can be used to determine the dimension of the hollow cavity. It
should be appreciated that the emitter and sensor 18 can be
incorporated into a single transceiver that is capable of both
emitting energy and detecting the reflected energy.
[0218] FIG. 2A illustrates a longitudinal section of the ablation
device, depicting a distribution of infusion ports. FIG. 2B
illustrates a cross section of a distribution of infusion ports on
the ablation device, in accordance with an embodiment of the
present specification. The longitudinal and cross sectional view of
the catheter 10 as illustrated in FIGS. 2A and 2B respectively,
show one arrangement of the infusion ports 12 to produce a uniform
distribution of ablative agent 21 in order to provide a
circumferential area of ablation in a hollow organ 20. FIG. 2C
illustrates a cross section of a distribution of infusion ports on
the ablation device, in accordance with another embodiment of the
present specification. The arrangement of the infusion ports 12 as
illustrated in FIG. 2C produce a focal distribution of ablative
agent 21 and a focal area of ablation in a hollow organ 20.
[0219] For all embodiments described herein, it should be
appreciated that the size of the port, number of ports, and
distance between the ports will be determined by the volume of
ablative agent needed, pressure that the hollow organ can
withstand, size of the hollow organ as measured by the distance of
the surface from the port, length of the tissue to be ablated
(which is roughly the surface area to be ablated), characteristics
of the tissue to be ablated and depth of ablation needed. In one
embodiment, there is at least one port opening that has a diameter
between 1 .mu.m and 1 cm. In another embodiment, there are two or
more port openings that have a diameter between 1 .mu.m and 1 cm
and that are equally spaced around the perimeter of the device.
[0220] FIG. 2D illustrates another embodiment of the ablation
device. The vapor ablation catheter comprises an insulated catheter
21 with one or more positioning attachments 22 of known length 23.
The vapor ablation catheter has one or more vapor infusion ports
25. The length 24 of the vapor ablation catheter 21 with infusion
ports 25 is determined by the length or area of the tissue to be
ablated. Vapor 29 is delivered through the vapor infusion ports 25.
The catheter 21 is preferably positioned in the center of the
positioning attachment 22, and the infusion ports 25 are arranged
circumferentially for circumferential ablation and delivery of
vapor. In another embodiment, the catheter 21 can be positioned
toward the periphery of the positioning attachment 22 and the
infusion ports 25 can be arranged non-circumferentially, preferably
linearly on one side for focal ablation and delivery of vapor. The
positioning attachment 22 is one of an inflatable balloon, a wire
mesh disc with or without an insulated membrane covering the disc,
a cone shaped attachment, a ring shaped attachment or a freeform
attachment designed to fit the desired hollow body organ or hollow
body passage, as further described below. Optional infrared,
electromagnetic, acoustic or radiofrequency energy emitters and
sensors 28 are incorporated to measure the dimensions of the hollow
organ.
[0221] The vapor ablation catheter may also comprise an optional
coaxial sheet 27 to restrain the positioning attachment 22 in a
manner comparable to a coronary metal stent. In one embodiment, the
sheet is made of memory metal or memory material with a compressed
linear form and a non-compressed form in the shape of the
positioning attachment. Alternatively, the channel of an endoscope
may perform the function of restraining the positioning attachment
22 by, for example, acting as a constraining sheath. Optional
sensor 26 is deployed on the catheter to measure changes associated
with vapor delivery or ablation. The sensor is one of temperature,
pressure, photo or chemical sensor.
[0222] Optionally, one or more, infrared, electromagnetic, acoustic
or radiofrequency energy emitters and sensors 28 can measure the
dimensions of the hollow organ. The infrared, electromagnetic,
acoustic or radiofrequency energy is emitted from the emitter 28
and is reflected back from the tissue to the detector in the
emitter 28. The reflected data can be used to determine the
dimension of the hollow cavity. The measurement is performed at one
or multiple points to get an accurate estimate of the dimension of
the hollow organ. The data can also be used to create a topographic
representation of the hollow organ. Additional data from diagnostic
tests can be used to validate or add to the data from the above
measurements.
[0223] FIG. 2E illustrates a catheter 21 of the ablation device, in
accordance with another embodiment of the present specification.
The catheter 21 is similar to that described with reference to FIG.
2D, however, the catheter 21 of FIG. 2E additionally includes at
least one port 19 for the delivery of a conductive medium 31. In
one embodiment, the conductive medium 31 is injected into the
hollow tissue or organ prior to the introduction of the ablative
agent 29. Once the tissue has been filled to an appropriate level
with the conductive medium 31, ablative agent 29 is then delivered
into the conductive medium 31 filled tissue. The conductive medium
31 acts to evenly distribute the ablative agent 29, resulting in
more consistent and effective ablation of the target tissue.
[0224] FIG. 2F illustrates a catheter 21 of the ablation device, in
accordance with yet another embodiment of the present
specification. The catheter 21 is similar to that described with
reference to FIG. 2E, however, the catheter 21 of FIG. 2F
additionally includes at least one port 30 for the removal via
suction of the natural contents of the hollow tissue or organ. In
one embodiment, the natural contents of the hollow tissue or organ
are removed prior to the introduction of the conductive medium 31
or the ablative agent 29.
[0225] In another embodiment, as depicted in FIG. 2E, wherein the
catheter includes at least one port 25 for the delivery of ablative
agent and at least one other port 19 for the delivery of a
conductive medium, the natural contents of the hollow tissue or
organ can be removed via suction using the ablative agent delivery
port 25. In another embodiment, as depicted in FIG. 2E, wherein the
catheter includes at least one port 25 for the delivery of ablative
agent and at least one other port 19 for the delivery of a
conductive medium, the natural contents of the hollow tissue or
organ can be removed via suction using the conductive medium
delivery port 19. In yet another embodiment, as depicted in FIG.
2D, the conductive medium can be delivered, and, the natural
contents of the hollow tissue or organ can be removed via suction,
using the ablative agent delivery port 25. In various embodiments,
after ablation of the target tissue(s), the remaining contents of
the hollow tissue or organ are removed via suction using one or
more of the ports described above.
[0226] In various embodiments, with respect to the catheters
depicted in FIGS. 2A-2F, the ablative agent can be any one of
steam, liquid nitrogen, or any other suitable ablative agent.
[0227] FIG. 2G is a flow chart listing the steps involved in a
hollow tissue or organ ablation process using the ablation device,
in accordance with one embodiment of the present specification. At
step 202, an endoscope is inserted into a patient. An ablation
device comprising a catheter in accordance with one embodiment of
the present specification, is advanced through a working channel of
the endoscope and to a target tissue at step 204. At step 206, the
distal end or tip of the catheter is inserted into the target
hollow tissue or organ. Then, at step 208, suction is applied at
the proximal end of the catheter to remove the natural contents of
the hollow tissue or organ. A conductive medium is then injected,
at step 210, into the hollow tissue or organ via at least one port
on the distal end of the catheter. At step 212, an ablative agent
is delivered into the conductive medium for ablation of the target
tissue. At step 214, the remaining contents of the tissue,
including conductive medium and ablative agent, are removed via
suction using the catheter. In another embodiment, step 214 is
optional, and the remaining contents of the hollow tissue or organ
are reabsorbed by the body. In another embodiment, the removal of
the natural contents of the hollow tissue or organ at step 208 is
optional, and the procedure moves directly to the injection of
conductive medium at step 210 from entering the target tissue with
the catheter at step 206.
[0228] FIG. 2H illustrates an ablation device 20 in the form of a
catheter 21 extending from a conventional handle 22, in accordance
with an embodiment of the present specification. The catheter 21 is
of a type as described above and extends from and attaches to the
handle 22. In one embodiment, the catheter 21 is insulated to
protect the user from burns that could result from hot vapor
heating the catheter. In one embodiment, the catheter is composed
of a material that will ensure that the outer temperature of the
catheter will remain below 60.degree. C. during use. The handle 22
includes a pressure resistant port at the point of attachment with
the catheter 21. The handle 22 also includes a flow channel within
that directs vapor through to the catheter 21.
[0229] In one embodiment, the snare handle 22 includes a single
attachment port 23 for the connection of a vapor stream and an RF
feed. In another embodiment (not shown), the snare handle includes
two separate attachment ports for the connection of a vapor stream
and an RF feed. The attachment port 23 interfaces with the vapor
supply cord via pressure-resistant connectors. In one embodiment,
the connectors are of a luer lock type. In one embodiment, the
catheter 21 is a dual lumen catheter. The first lumen serves to
deliver vapor to the site of ablation. In one embodiment, the vapor
is released through small ports 24 positioned proximate the distal
end of the catheter 21. The distal end of the catheter 21 is
designed so that it can puncture the tissue to deliver vapor to the
desired depth and location within the target tissue. In one
embodiment, the distal end of the catheter 21 tapers to a point.
The second lumen houses the electrode used for RF ablation. In one
embodiment, the delivery of vapor or RF waves is achieved through
the use of a microprocessor. In another embodiment, the user can
release vapor or subject the target tissue to RF waves by the use
of actuators (not shown) on the handle 22. In one embodiment, the
catheter has varying or differential insulation along its length.
In one embodiment, the ablation device 20 includes a mechanism in
which a snare to grasp the tissue to be ablated and sizing the
tissue in the snare is used to determine the amount of vapor to be
delivered.
[0230] FIG. 2I illustrates a cross section of an ablation device 27
in the form of a catheter 21 extending from a conventional handle
22 with a pre-attached cord 25, in accordance with another
embodiment of the present specification. The cord 25 attaches
directly to the vapor delivery system, eliminating one interface
between the system and the ablation device and thereby decreasing
the chance of system failure as a result of disconnection. In this
embodiment, the handle 22 includes a separate attachment port (not
shown) for the RF or an electric feed.
[0231] FIG. 2J illustrates an ablation device 29 in the form of a
catheter 21 extending from a conventional esophageal probe 26, in
accordance with an embodiment of the present specification. In one
embodiment, the catheter 21 is insulated and receives vapor from a
flow channel contained within the probe 26. The catheter 21
includes a multitude of small ports 24 for the delivery of vapor to
the target tissue. The delivery of vapor is controlled by a
microprocessor. In one embodiment, the catheter 21 also includes
two inflatable balloons 28, one at its distal end beyond the last
vapor port 24, and one at its proximal end, proximate the
catheter's 21 attachment to the probe 26. All vapor ports are
positioned between these two balloons. Once the device 29 is
inserted within the esophagus, the balloons 28 are inflated to keep
the catheter 21 positioned and to contain the vapor within the
desired treatment area. In one embodiment, the balloons must be
separated from the ablation region by a distance of greater than 0
mm, preferably 1 mm and ideally 1 cm. In one embodiment, the
diameter of each balloon when inflated is in the range of 10 to 100
mm, preferably 15-40 mm, although one of ordinary skill in the art
would appreciate that the precise dimensions are dependent on the
size of the patient's esophagus.
[0232] In one embodiment, the catheter 21 attached to the
esophageal probe 26 is a dual lumen catheter. The first lumen
serves to deliver vapor to the site of ablation as described above.
The second lumen houses the electrode used for RF ablation.
[0233] FIG. 3A illustrates the ablation device placed in an upper
gastrointestinal tract with Barrett's esophagus to selectively
ablate the Barrett's tissue, in accordance with an embodiment of
the present specification. The upper gastrointestinal tract
comprises Barrett's esophagus 31, gastric cardia 32,
gastroesophageal junction 33 and displaced squamo-columnar junction
34. The area between the gastroesophageal junction 33 and the
displaced squamo-columnar junction 34 is Barrett's esophagus 31,
which is targeted for ablation. Distal to the cardia 32 is the
stomach 35 and proximal to the cardia 32 is the esophagus 36. The
ablation device is passed into the esophagus 36 and the positioning
device 11 is placed in the gastric cardia 32 abutting the
gastroesophageal junction 33. This affixes the ablation catheter 10
and its ports 12 in the center of the esophagus 36 and allows for
uniform delivery of the ablative agent 21 to the Barrett's
esophagus 31.
[0234] In one embodiment, the positioning device is first affixed
to an anatomical structure, not being subjected to ablation, before
ablation occurs. Where the patient is undergoing circumferential
ablation or first time ablation, the positioning attachment is
preferably placed in the gastric cardia, abutting the
gastroesophageal junction. Where the patient is undergoing a focal
ablation of any residual disease, it is preferable to use the
catheter system shown in FIG. 4B, as discussed below. In one
embodiment, the positioning attachment must be separated from the
ablation region by a distance of greater than 0 mm, preferably 1 mm
and ideally 1 cm. In one embodiment, the size of the positioning
device is in the range of 10 to 100 mm, preferably 20-40 mm,
although one of ordinary skill in the art would appreciate that the
precise dimensions are dependent on the size of the patient's
esophagus.
[0235] The delivery of ablative agent 21 through the infusion port
12 is controlled by the microprocessor 15 coupled with the ablation
device. The delivery of ablative agent is guided by predetermined
programmatic instructions, depending on the tissue to be ablated
and the depth of ablation required. In one embodiment, the target
procedural temperature will need to be between -100 degrees Celsius
and 200 degrees Celsius, preferably between 50 degrees Celsius and
75 degrees Celsius, as further shown in the dosimetery table below.
In one embodiment, esophageal pressure should not exceed 5 atm, and
is preferably below 0.5 atm. In one embodiment, the target
procedural temperature is achieved in less than 1 minute,
preferably in less than 5 seconds, and is capable of being
maintained for up to 10 minutes, preferably 1 to 10 seconds, and
then cooled to body temperature. One of ordinary skill in the art
would appreciate that the treatment can be repeated until the
desired ablation effect is achieved.
[0236] Optional sensor 17 monitors intraluminal parameters such as
temperature and pressure and can increase or decrease the flow of
ablative agent 21 through the infusion port 12 to obtain adequate
heating or cooling, resulting in adequate ablation. The sensor 17
monitors intraluminal parameters such as temperature and pressure
and can increase or decrease the removal of ablative agent 21
through the optional suction port 13 to obtain adequate heating or
cooling resulting in adequate ablation of Barrett's esophagus 31.
FIG. 3B illustrates the ablation device placed in an upper
gastrointestinal tract with Barrett's esophagus to selectively
ablate the Barrett's tissue, in accordance with another embodiment
of the present specification. As illustrated in FIG. 3B, the
positioning device 11 is a wire mesh disc. In one embodiment, the
positioning attachment must be separated from the ablation region
by a distance of greater than 0 mm, preferably 1 mm and ideally 1
cm. In one embodiment, the positioning attachment is removably
affixed to the cardia or gastroesophageal (EG) junction (for the
distal attachment) or in the esophagus by a distance of greater
than 0.1 mm, preferably around 1 cm, above the proximal most extent
of the Barrett's tissue (for the proximal attachment).
[0237] FIG. 3B is another embodiment of the Barrett's ablation
device where the positioning element 11 is a wire mesh disc. The
wire mesh may have an optional insulated membrane to prevent the
escape of the ablative agent. In the current embodiment, two wire
mesh discs are used to center the ablation catheter in the
esophagus. The distance between the two discs is determined by the
length of the tissue to be ablated which, in this case, would be
the length of the Barrett's esophagus. Optional infrared,
electromagnetic, acoustic or radiofrequency energy emitters and
sensors 18 are incorporated to measure the diameter of the
esophagus.
[0238] FIG. 3C is a flowchart illustrating the basic procedural
steps for using the ablation device, in accordance with an
embodiment of the present specification. At step 302, a catheter of
the ablation device is inserted into an organ which is to be
ablated. For example, in order to perform ablation in a Barrett's
esophagus of a patient, the catheter is inserted into the Barrett's
esophagus via the esophagus of the patient.
[0239] At step 304, a positioning element of the ablation device is
deployed and organ dimensions are measured. In an embodiment, where
the positioning element is a balloon, the balloon is inflated in
order to position the ablation device at a known fixed distance
from the tissue to be ablated. In various embodiments, the diameter
of the hollow organ may be predetermined by using radiological
tests such as barium X-rays or computer tomography (CT) scan, or by
using pressure volume cycle, i.e. by determining volume needed to
raise pressure to a fixed level (for example, 1 atm) in a fixed
volume balloon. In another embodiment, where the positioning device
is disc shaped, circumferential rings are provided in order to
visually communicate to an operating physician the diameter of the
hollow organ. In various embodiments of the present specification,
the positioning device enables centering of the catheter of the
ablation device in a non-cylindrical body cavity, and the volume of
the cavity is measured by the length of catheter or a uterine
sound.
[0240] Optionally, one or more infrared, electromagnetic, acoustic
or radiofrequency energy emitters and sensors can be used to
measure the dimensions of the hollow organ. The infrared,
electromagnetic, acoustic or radiofrequency energy is emitted from
the emitter and is reflected back from the tissue to a detector in
the emitter. The reflected data can be used to determine the
dimensions of the hollow cavity. The measurement can be performed
at one or multiple points to get an accurate estimate of the
dimensions of the hollow organ. The data from multiple points can
also be used to create a topographic representation of the hollow
organ or to calculate the volume of the hollow organ.
[0241] In one embodiment, the positioning attachment must be
separated from the ports by a distance of 0 mm or greater,
preferably greater than 0.1 mm, and more preferably 1 cm. The size
of the positioning device depends on the hollow organ being ablated
and ranges from 1 mm to 10 cm. In one embodiment, the diameter of
the positioning element is between 0.01 mm and 100 mm. In one
embodiment, the first positioning element comprises a circular body
with a diameter between 0.01 mm and 10 cm.
[0242] At step 306, the organ is ablated by automated delivery of
an ablative agent, such as steam, via infusion ports provided on
the catheter. The delivery of the ablative agent through the
infusion ports is controlled by a microprocessor coupled with the
ablation device. The delivery of ablative agent is guided by
predetermined programmatic instructions depending on the tissue to
be ablated and the depth of ablation required. In an embodiment of
the present specification where the ablative agent is steam, the
dose of the ablative agent is determined by conducting dosimetery
study to determine the dose to ablate endometrial tissue. The
variable that enables determination of total dose of ablative agent
is the volume (or mass) of the tissue to be treated which is
calculated by using the length of the catheter and diameter of the
organ (for cylindrical organs). The determined dose of ablative
agent is then delivered using a micro-processor controlled steam
generator. Optionally, the delivery of the ablative agent can be
controlled by the operator using predetermined dosimetry
parameters.
[0243] In one embodiment, the dose is provided by first determining
what the disorder being treated is and what the desired tissue
effect is, and then finding the corresponding temperature, as shown
in Tables 1 and 2, below.
TABLE-US-00001 TABLE 1 Temp in .degree. C. Tissue Effect 37-40 No
significant tissue effect 41-44 Reversible cell damage in few hours
45-49 Irreversible cell damage at shorter intervals 50-69
Irreversible cell damage -ablation necrosis at shorter intervals 70
Threshold temp for tissue shrinkage, H-bond breakage 70-99
Coagulation and Hemostasis 100-200 Desiccation and Carbonization of
tissue >200 Charring of tissue glucose
TABLE-US-00002 TABLE 2 Disorder Max. Temp in .degree. C.
ENT/Pulmonary Nasal Polyp 60-80 Turbinectomy 70-85 Bullous Disease
70-85 Lung Reduction 70-85 Genitourinary Uterine Menorrhagia 80-90
Endometriosis 80-90 Uterine Fibroids 90-100 Benign Prostatic
Hypertrophy 90-100 Gastroenterology Barrett's Esophagus 60-75
Esophageal Dysplasia 60-80 Vascular GI Disorders 55-75 Flat Polyps
60-80
[0244] In addition, the depth of ablation desired determines the
holding time at the maximum temperature. For superficial ablation
(Barrett), the holding time at the maximum temperature is very
short (flash burn) and does not allow for heat to transfer to the
deeper layers. This will prevent damage to deeper normal tissue and
hence prevent patient discomfort and complications. For deeper
tissue ablation, the holding time at the maximum temperature will
be longer, thereby allowing the heat to percolate deeper.
[0245] FIG. 4A illustrates the ablation device placed in a colon to
ablate a flat colon polyp, in accordance with an embodiment of the
present specification. The ablation catheter 10 is passed through a
colonoscope 40. The positioning device 11 is placed proximal, with
respect to the patient's GI tract, to a flat colonic polyp 41 which
is to be ablated, in the normal colon 42. The positioning device 11
is one of an inflatable balloon, a wire mesh disc with or without
an insulated membrane covering the disc, a cone shaped attachment,
a ring shaped attachment or a freeform attachment designed to fit
the colonic lumen. The positioning device 11 has the catheter 10
located toward the periphery of the positioning device 11 placing
it closer to the polyp 41 targeted for non-circumferential
ablation. Hence, the positioning device 11 fixes the catheter to
the colon 42 at a predetermined distance from the polyp 41 for
uniform and focused delivery of the ablative agent 21. The delivery
of ablative agent 21 through the infusion port 12 is controlled by
the microprocessor 15 attached to the ablation device and depends
on tissue and the depth of ablation required. The delivery of
ablative agent 21 is guided by predetermined programmatic
instructions depending on the tissue to be ablated and the area and
depth of ablation required. Optional infrared, electromagnetic,
acoustic or radiofrequency energy emitters and sensors 18 are
incorporated to measure the diameter of the colon. The ablation
device allows for focal ablation of diseased polyp mucosa without
damaging the normal colonic mucosa located away from the catheter
ports.
[0246] In one embodiment, the positioning attachment must be
separated from the ablation region by a distance of greater than
0.1 mm, ideally more than 5 mm. In one embodiment, the positioning
element is proximal, with respect to the patient's GI tract, to the
colon polyp. For this application, the embodiment shown in FIG. 4B
would be preferred.
[0247] FIG. 4B illustrates the ablation device placed in a colon 42
to ablate a flat colon polyp 41, in accordance with another
embodiment of the present specification. As illustrated in FIG. 4B,
the positioning device 11 is a conical attachment at the tip of the
catheter 10. The conical attachment has a known length `1` and
diameter `d` that is used to calculate the amount of thermal energy
needed to ablate the flat colon polyp 41. Ablative agent 21 is
directed from the infusion port 12 to polyp 41 by the positioning
device 11. In one embodiment, the positioning attachment 11 must be
separated from the ablation region by a distance of greater than
0.1 mm, preferably 1 mm and more preferably 1 cm. In one
embodiment, the length `1` is greater than 0.1 mm, preferably
between 5 and 10 mm. In one embodiment, diameter `d` depends on the
size of the polyp and can be between 1 mm and 10 cm, preferably 1
to 5 cm. Optional infrared, electromagnetic, acoustic or
radiofrequency energy emitters and sensors 18 are incorporated to
measure the diameter of the colon. This embodiment can also be used
to ablate residual neoplastic tissue at the edges after endoscopic
snare resection of a large sessile colon polyp.
[0248] FIG. 5A illustrates the ablation device with a coaxial
catheter design, in accordance with an embodiment of the present
specification. The coaxial design has a handle 52a, an infusion
port 53a, an inner sheath 54a and an outer sheath 55a. The outer
sheath 55a is used to constrain the positioning device 56a in the
closed position and encompasses ports 57a. FIG. 5B shows a
partially deployed positioning device 56b, with the ports 57b still
within the outer sheath 55b. The positioning device 56b is
partially deployed by pushing the catheter 54b out of sheath
55b.
[0249] FIG. 5C shows a completely deployed positioning device 56c.
The infusion ports 57c are out of the sheath 55c. The length `1` of
the catheter 54c that contains the infusion ports 57c and the
diameter `d` of the positioning element 56c are predetermined/known
and are used to calculate the amount of thermal energy needed. FIG.
5D illustrates a conical design of the positioning element. The
positioning element 56d is conical with a known length `1` and
diameter `d` that is used to calculate the amount of thermal energy
needed for ablation. FIG. 5E illustrates a disc shaped design of
the positioning element 56e comprising circumferential rings 59e.
The circumferential rings 59e are provided at a fixed predetermined
distance from the catheter 54e and are used to estimate the
diameter of a hollow organ or hollow passage in a patient's
body.
[0250] FIG. 6 illustrates an upper gastrointestinal tract with a
bleeding vascular lesion being treated by the ablation device, in
accordance with an embodiment of the present specification. The
vascular lesion is a visible vessel 61 in the base of an ulcer 62.
The ablation catheter 63 is passed through the channel of an
endoscope 64. The conical positioning element 65 is placed over the
visible vessel 61. The conical positioning element 65 has a known
length `1` and diameter `d`, which are used to calculate the amount
of thermal energy needed for coagulation of the visible vessel to
achieve hemostasis. The conical positioning element has an optional
insulated membrane that prevents escape of thermal energy or vapor
away from the disease site.
[0251] In one embodiment, the positioning attachment must be
separated from the ablation region by a distance of greater than
0.1 mm, preferably 1 mm and more preferably 1 cm. In one
embodiment, the length `1` is greater than 0.1 mm, preferably
between 5 and 10 mm. In one embodiment, diameter `d` depends on the
size of the lesion and can be between 1 mm and 10 cm, preferably 1
to 5 cm.
[0252] FIG. 7A illustrates endometrial ablation being performed in
a female uterus by using the ablation device, in accordance with an
embodiment of the present specification. A cross-section of the
female genital tract comprising a vagina 70, a cervix 71, a uterus
72, an endometrium 73, fallopian tubes 74, ovaries 75 and the
fundus of the uterus 76 is illustrated. A catheter 77 of the
ablation device is inserted into the uterus 72 through the cervix
71 at the cervical os. In an embodiment, the catheter 77 has two
positioning elements, a conical positioning element 78 and a disc
shaped positioning element 79. The positioning element 78 is
conical with an insulated membrane covering the conical positioning
element 78. The conical element 78 positions the catheter 77 in the
center of the cervix 71 and the insulated membrane prevents the
escape of thermal energy or ablative agent out the cervix 71
through the os. The second disc shaped positioning element 79 is
deployed close to the fundus of the uterus 76 positioning the
catheter 77 in the middle of the cavity. An ablative agent 778 is
passed through infusion ports 777 for uniform delivery of the
ablative agent 778 into the uterine cavity. Predetermined length
`l` of the ablative segment of the catheter and diameter `d` of the
positioning element 79 allows for estimation of the cavity size and
is used to calculate the amount of thermal energy needed to ablate
the endometrial lining. In one embodiment, the positioning elements
78, 79 also act to move the endometrial tissue away from the
infusion ports 777 on the catheter 77 to allow for the delivery of
ablative agent. Optional temperature sensors 7 deployed close to
the endometrial surface are used to control the delivery of the
ablative agent 778. Optional topographic mapping using multiple
infrared, electromagnetic, acoustic or radiofrequency energy
emitters and sensors can be used to define cavity size and shape in
patients with an irregular or deformed uterine cavity due to
conditions such as fibroids. Additionally, data from diagnostic
testing can be used to ascertain the uterine cavity size, shape, or
other characteristics.
[0253] In an embodiment, the ablative agent is vapor or steam which
contracts on cooling. Steam turns to water which has a lower volume
as compared to a cryogen that will expand or a hot fluid used in
hydrothermal ablation whose volume stays constant. With both
cryogens and hot fluids, increasing energy delivery is associated
with increasing volume of the ablative agent which, in turn,
requires mechanisms for removing the agent, otherwise the medical
provider will run into complications, such as perforation. However,
steam, on cooling, turns into water which occupies significantly
less volume; therefore, increasing energy delivery is not
associated with an increase in volume of the residual ablative
agent, thereby eliminating the need for continued removal. This
further decreases the risk of leakage of the thermal energy via the
fallopian tubes 74 or the cervix 71, thus reducing any risk of
thermal injury to adjacent healthy tissue.
[0254] In one embodiment, the positioning attachment must be
separated from the ablation region by a distance of greater than
0.1 mm, preferably 1 mm and more preferably 1 cm. In another
embodiment, the positioning attachment can be in the ablated region
as long as it does not cover a significant surface area. For
endometrial ablation, 100% of the tissue does not need to be
ablated to achieve the desired therapeutic effect.
[0255] In one embodiment, the preferred distal positioning
attachment is an uncovered wire mesh that is positioned proximate
to the mid body region. In one embodiment, the preferred proximal
positioning device is a covered wire mesh that is pulled into the
cervix, centers the device, and occludes the cervix. One or more
such positioning devices may be helpful to compensate for the
anatomical variations in the uterus. The proximal positioning
device is preferably oval, with a long axis between 0.1 mm and 10
cm (preferably 1 cm to 5 cm) and a short axis between 0.1 mm and 5
cm (preferably 0.5 cm to 1 cm). The distal positioning device is
preferably circular with a diameter between 0.1 mm and 10 cm,
preferably 1 cm to 5 cm.
[0256] In another embodiment, the catheter is a coaxial catheter
comprising an external catheter and an internal catheter wherein,
upon insertion, the distal end of the external catheter engages and
stops at the cervix while the internal extends into the uterus
until its distal end contacts the fundus of the uterus. The length
of the internal catheter that has passed into the uterus is then
used to measure the depth of the uterine cavity and determines the
amount of ablative agent to use. Ablative agent is then delivered
to the uterine cavity via at least one port on the internal
catheter. In one embodiment, during treatment, intracavitary
pressure within the uterus is kept below 100 mm Hg. In one
embodiment, the coaxial catheter further includes a pressure sensor
to measure intracavitary pressure. In one embodiment, the coaxial
catheter further includes a temperature sensor to measure
intracavitary temperature. In one embodiment, the ablative agent is
steam and the steam is released from the catheter at a pressure of
less than 100 mm Hg. In one embodiment, the steam is delivered with
a temperature between 90 and 100.degree. C.
[0257] FIG. 7B is an illustration of a coaxial catheter 720 used in
endometrial tissue ablation, in accordance with one embodiment of
the present specification. The coaxial catheter 720 comprises an
inner catheter 721 and outer catheter 722. In one embodiment, the
inner catheter 721 has one or more ports 723 for the delivery of an
ablative agent 724. In one embodiment, the ablative agent is steam.
In one embodiment, the outer catheter 722 has multiple fins 725 to
engage the cervix to prevent the escape of vapor out of the uterus
and into the vagina. In one embodiment, the fins are composed of
silicone. In one embodiment, the outer catheter 722 includes a luer
lock 726 to prevent the escape of vapor between the inner catheter
721 and outer catheter 722. In one embodiment, the inner catheter
721 includes measurement markings 727 to measure the depth of
insertion of the inner catheter 721 beyond the tip of the outer
catheter 722. Optionally, in various embodiments, one or more
sensors 728 are incorporated into the inner catheter 721 to measure
intracavitary pressure or temperature.
[0258] FIG. 7C is a flow chart listing the steps involved in an
endometrial tissue ablation process using a coaxial ablation
catheter, in accordance with one embodiment of the present
specification. At step 702, the coaxial catheter is inserted into
the patient's vagina and advanced to the cervix. Then, at step 704,
the coaxial catheter is advanced such that the fins of the outer
catheter engage the cervix, effectively stopping advancement of the
outer catheter at that point. The inner catheter is then advanced,
at step 706, until the distal end of the internal catheter contacts
the fundus of the uterus. The depth of insertion is then measured
using the measurement markers on the internal catheter at step 708,
thereby determining the amount of ablative agent to use in the
procedure. At step 710, the luer lock is tightened to prevent any
escape of vapor between the two catheters. The vapor is then
delivered, at step 712, through the lumen of the inner catheter and
into the uterus via the delivery ports on the internal catheter to
ablate the endometrial tissue.
[0259] FIG. 8 illustrates sinus ablation being performed in a nasal
passage by using the ablation device, in accordance with an
embodiment of the present specification. A cross-section of the
nasal passage and sinuses comprising nares 81, nasal passages 82,
frontal sinus 83, ethmoid sinus 84, and diseased sinus epithelium
85 is illustrated. The catheter 86 is inserted into the frontal
sinus 83 or the ethmoid sinus 84 through the nares 81 and nasal
passages 82.
[0260] In an embodiment, the catheter 86 has two positioning
elements, a conical positioning element 87 and a disc shaped
positioning element 88. The positioning element 87 is conical and
has an insulated membrane covering. The conical element 87
positions the catheter 86 in the center of the sinus opening 80 and
the insulated membrane prevents the escape of thermal energy or
ablative agent through the opening. The second disc shaped
positioning element 88 is deployed in the frontal sinus cavity 83
or ethmoid sinus cavity 84, positioning the catheter 86 in the
middle of either sinus cavity. The ablative agent 8 is passed
through the infusion port 89 for uniform delivery of the ablative
agent 8 into the sinus cavity. The predetermined length `l` of the
ablative segment of the catheter and diameter `d` of the
positioning element 88 allows for estimation of the sinus cavity
size and is used to calculate the amount of thermal energy needed
to ablate the diseased sinus epithelium 85. Optional temperature
sensors 888 are deployed close to the diseased sinus epithelium 85
to control the delivery of the ablative agent 8. In an embodiment,
the ablative agent 8 is steam which contracts on cooling. This
further decreases the risk of leakage of the thermal energy thus
reducing any risk of thermal injury to adjacent healthy tissue. In
one embodiment, the dimensional ranges of the positioning elements
are similar to those in the endometrial application, with preferred
maximum ranges being half thereof. Optional topographic mapping
using multiple infrared, electromagnetic, acoustic or
radiofrequency energy emitters and sensors can be used to define
cavity size and shape in patients with an irregular or deformed
nasal cavity due to conditions such as nasal polyps.
[0261] FIG. 9 illustrates bronchial and bullous ablation being
performed in a pulmonary system by using the ablation device, in
accordance with an embodiment of the present specification. A
cross-section of the pulmonary system comprising bronchus 91,
normal alveolus 92, bullous lesion 93, and a bronchial neoplasm 94
is illustrated.
[0262] In one embodiment, the catheter 96 is inserted through the
channel of a bronchoscope 95 into the bronchus 91 and advanced into
a bullous lesion 93. The catheter 96 has two positioning elements,
a conical positioning element 97 and a disc shaped positioning
element 98. The positioning element 97 is conical having an
insulated membrane covering. The conical element 97 positions the
catheter 96 in the center of the bronchus 91 and the insulated
membrane prevents the escape of thermal energy or ablative agent
through the opening into the normal bronchus. The second disc
shaped positioning element 98 is deployed in the bullous cavity 93
positioning the catheter 96 in the middle of the bullous cavity 93.
An ablative agent 9 is passed through the infusion port 99 for
uniform delivery into the sinus cavity. Predetermined length `l` of
the ablative segment of the catheter 96 and diameter `d` of the
positioning element 98 allow for estimation of the bullous cavity
size and is used to calculate the amount of thermal energy needed
to ablate the diseased bullous cavity 93. Optionally, the size of
the cavity can be calculated from radiological evaluation using a
chest CAT scan or MRI. Optional temperature sensors are deployed
close to the surface of the bullous cavity 93 to control the
delivery of the ablative agent 9. In an embodiment, the ablative
agent is steam which contracts on cooling. This further decreases
the risk of leakage of the thermal energy into the normal bronchus
thus reducing any risk of thermal injury to adjacent normal
tissue.
[0263] In one embodiment, the positioning attachment must be
separated from the ablation region by a distance of greater than
0.1 mm, preferably 1 mm and more preferably 1 cm. In another
embodiment, the positioning attachment can be in the ablated region
as long as it does not cover a significant surface area.
[0264] In one embodiment, there are preferably two positioning
attachments. In another embodiment, the endoscope is used as one
fixation point with one positioning element. The positioning device
is between 0.1 mm and 5 cm (preferably 1 mm to 2 cm). The distal
positioning device is preferably circular with a diameter between
0.1 mm and 10 cm, preferably 1 cm to 5 cm.
[0265] In another embodiment for the ablation of a bronchial
neoplasm 94, the catheter 96 is inserted through the channel of a
bronchoscope 95 into the bronchus 91 and advanced across the
bronchial neoplasm 94. The positioning element 98 is disc shaped
having an insulated membrane covering. The positioning element 98
positions the catheter in the center of the bronchus 91 and the
insulated membrane prevents the escape of thermal energy or
ablative agent through the opening into the normal bronchus. The
ablative agent 9 is passed through the infusion port 99 in a
non-circumferential pattern for uniform delivery of the ablative
agent to the bronchial neoplasm 94. The predetermined length `l` of
the ablative segment of the catheter and diameter `d` of the
positioning element 98 are used to calculate the amount of thermal
energy needed to ablate the bronchial neoplasm 94.
[0266] The catheter could be advanced to the desired location of
ablation using endoscopic, laparoscopic, stereotactic or
radiological guidance. Optionally the catheter could be advanced to
the desired location using magnetic navigation.
[0267] FIG. 10A illustrates prostate ablation being performed on an
enlarged prostrate in a male urinary system by using the device, in
accordance with an embodiment of the present specification. A
cross-section of a male genitourinary tract having an enlarged
prostate 1001, bladder 1002, and urethra 1003 is illustrated. The
urethra 1003 is compressed by the enlarged prostate 1001. The
ablation catheter 1005 is passed through the cystoscope 1004
positioned in the urethra 1003 distal to the obstruction. The
positioning elements 1006 are deployed to center the catheter in
the urethra 1003 and one or more insulated needles 1007 are passed
to pierce the prostate 1001. The vapor ablative agent 1008 is
passed through the insulated needles 1007 thus causing ablation of
the diseased prostatic tissue resulting in shrinkage of the
prostate.
[0268] The size of the enlarged prostate could be calculated by
using the differential between the extra-prostatic and
intra-prostatic urethra. Normative values could be used as
baseline. Additional ports for infusion of a cooling fluid into the
urethra can be provided to prevent damage to the urethra while the
ablative energy is being delivered to the prostrate for ablation,
thus preventing complications such as stricture formation.
[0269] In one embodiment, the positioning attachment must be
separated from the ablation region by a distance of greater than
0.1 mm, preferably 1 mm to 5 mm and no more than 2 cm. In another
embodiment, the positioning attachment can be deployed in the
bladder and pulled back into the urethral opening/neck of the
bladder thus fixing the catheter. In one embodiment, the
positioning device is between 0.1 mm and 10 cm in diameter.
[0270] FIG. 10B is an illustration of transurethral prostate
ablation being performed on an enlarged prostrate 1001 in a male
urinary system using an ablation device, in accordance with one
embodiment of the present specification. Also depicted in FIG. 10B
are the urinary bladder 1002 and prostatic urethra 1003. An
ablation catheter 1023 with a handle 1020 and a positioning element
1028 is inserted into the urethra 1003 and advanced into the
bladder 1002. The position element 1028 is inflated and pulled to
the junction of the bladder with the urethra, thus positioning
needles 1007 at a predetermined distance from the junction. Using a
pusher 1030, the needles 1007 are then pushed out at an angle
between 30 and 90 degree from the catheter 1023 through the urethra
1003 into the prostate 1001. Vapor is administered through a port
1038 that travels through the shaft of the catheter 1023 and exits
from openings 1037 in the needles 1007 into the prostatic tissue,
thus ablating the prostatic tissue. In one embodiment, the needles
1007 are insulated. Optional port 1039 allows for insertion of cool
fluid at a temperature <37 degree C. through opening 1040 to
cool the prostatic urethra. Optional temperature sensors 1041 can
be installed to detect the temperature of the prostatic urethra and
modulate the delivery of vapor.
[0271] FIG. 10C is an illustration of transurethral prostate
ablation being performed on an enlarged prostrate 1001 in a male
urinary system using an ablation device, in accordance with another
embodiment of the present specification. Also depicted in FIG. 10B
are the urinary bladder 1002 and prostatic urethra 1003. An
ablation catheter 1023 with a handle 1020 and a positioning element
1048 is inserted into the urethra 1003 and advanced into the
bladder 1002. The positioning element 1048 is a compressible disc
that is expanded in the bladder 1002 and pulled to the junction of
the bladder with the urethra, thus positioning needles 1007 at a
predetermined distance from the junction. Using a pusher 1030, the
needles 1007 are then pushed out at an angle between 30 and 90
degree from the catheter 1023 through the urethra 1003 into the
prostate 1001. Vapor is administered through a port 1038 that
travels through the shaft of the catheter 1023 and exits through
openings 1037 in the needles 17 into the prostatic tissue, thus
ablating the prostatic tissue. In one embodiment, the needles 1007
are insulated. Optional port 1039 allows for insertion of cool
fluid at a temperature <37 degree C. through opening 1040 to
cool the prostatic urethra. Optional temperature sensors 1041 can
be installed to detect the temperature of the prostatic urethra and
modulate the delivery of vapor.
[0272] FIG. 10D is a flow chart listing the steps involved in a
transurethral enlarged prostate ablation process using an ablation
catheter, in accordance with one embodiment of the present
specification. At step 1012, an ablation catheter is inserted into
the urethra and advanced until its distal end is in the bladder. A
positioning element is then deployed on the distal end of the
catheter, at step 1014, and the proximal end of the catheter is
pulled so that the positioning element abuts the junction of the
bladder with the urethra, thereby positioning the catheter shaft
within the urethra. A pusher at the proximal end of the catheter is
actuated to deploy needles from the catheter shaft through the
urethra and into the prostatic tissue at step 1016. At step 1018,
an ablative agent is delivered through the needles and into the
prostate to ablate the target prostatic tissue.
[0273] FIG. 10E is an illustration of transrectal prostate ablation
being performed on an enlarged prostrate in a male urinary system
using an ablation device, in accordance with one embodiment of the
present specification. Also depicted in FIG. 10E are the urinary
bladder 1002 and prostatic urethra 1003. The ablation device
comprises a catheter 1023 with a needle tip 1024. An endoscope 1022
is inserted into the rectum 1021 for the visualization of the
enlarged prostate 1001. In various embodiments, the endoscope 1022
is an echoendoscope or a transrectal ultrasound such that the
endoscope can be visualized using radiographic techniques. The
catheter 1023 with needle tip 1024 is passed through a working
channel of the endoscope and transrectally into the prostate 1001.
An ablative agent is then delivered through the needle tip 1024
into the prostatic tissue for ablation. In one embodiment, the
catheter 1023 and needle tip 1024 are composed of a thermally
insulated material. In various embodiments, the needle tip 1024 is
an echotip or sonolucent tip that can be observed using radiologic
techniques for accurate localization in the prostate tissue. In one
embodiment, an optional catheter (not shown) can be placed in the
urethra to insert fluid to cool the prostatic urethra 1003. In one
embodiment, the inserted fluid has a temperature less than
37.degree. C.
[0274] FIG. 10F is an illustration of transrectal prostate ablation
being performed on an enlarged prostrate in a male urinary system
using a coaxial ablation device having a positioning element, in
accordance with another embodiment of the present specification.
Also depicted in FIG. 10F are the urinary bladder 1002 and
prostatic urethra 1003. The ablation device comprises a coaxial
catheter 1023 having an internal catheter with a needle tip 1024
and an external catheter with a positioning element 1028. An
endoscope 1022 is inserted into the rectum 1021 for the
visualization of the enlarged prostate 1001. In various
embodiments, the endoscope 1022 is an echoendoscope or a
transrectal ultrasound such that the endoscope can be visualized
using radiographic techniques. The coaxial catheter 1023 with
needle tip 1024 and positioning element 1028 is passed through a
working channel of the endoscope such that the positioning element
1028 comes to rest up against the rectal wall and the internal
catheter is advanced transrectally, thereby positioning the needle
tip 1024 at a predetermined depth in the prostate 1001. In one
embodiment, the positioning element is a compressible disc that has
a first, compressed pre-employment configuration and a second,
expanded deployed configuration once it has passed beyond the
distal end of the endoscope 1022. An ablative agent is then
delivered through the needle tip 1024 into the prostatic tissue for
ablation. In one embodiment, the coaxial catheter 1023, needle tip
1024, and positioning element 1028 are composed of a thermally
insulated material. In various embodiments, the needle tip 1024 is
an echotip or sonolucent tip that can be observed using radiologic
techniques for accurate localization in the prostate tissue. In one
embodiment, an optional catheter (not shown) can be placed in the
urethra to insert fluid to cool the prostatic urethra 1003. In one
embodiment, the inserted fluid has a temperature less than
37.degree. C.
[0275] FIG. 10G is a flow chart listing the steps involved in a
transrectal enlarged prostate ablation process using an ablation
catheter, in accordance with one embodiment of the present
specification. At step 1042, an endoscope is inserted into the
rectum of a patient for visualization of the prostate. A catheter
with a needle tip is then advanced, at step 1044, through a working
channel of the endoscope and through the rectal wall and into the
prostate. Radiologic methods are used to guide the needle into the
target prostatic tissue at step 1046. At step 1048, an ablative
agent is delivered through the needle and into the prostate to
ablate the target prostatic tissue.
[0276] FIG. 10H is an illustration of an ablation catheter 1050 for
permanent implantation in the body to deliver repeat ablation and
FIG. 10I is a trocar 1056 used to place the ablation catheter 1050
in the body. FIG. 10J is an illustration of the catheter 1050 of
FIG. 10H and trocar 1056 of FIG. 10I assembled for placement of the
catheter 1050 into tissue targeted for ablation in the human body.
The catheter 1050 of FIG. 10H has an anchoring unit 1054, a shaft
1055 and a port 1057. The anchoring unit 1054 anchors the catheter
1050 in the tissue targeted for ablation and houses one or more
openings 1059 for the exit of the ablative agent. Port 1057 resides
in the subcutaneous tissue or at a site that is easily accessible
for repeat ablation. An ablative agent is introduced into the port
1057 and travels through the shaft 1055 to the site for ablation
and exits through the one or more openings 1059 in the anchoring
unit 1054. As illustrated in FIG. 10J, in the assembled
configuration 1053, the trocar 1056 locks with the catheter 1050
and straightens the anchoring unit 1054 for easy placement of the
catheter 1050. Alternatively, in one embodiment (not pictured), the
anchoring unit is a balloon that is inflated to anchor the device
in the desired tissue. The subcutaneous port 1057, in a manner
similar to a subcutaneous port for chemotherapy, can be easily
accessed using an insulated needle or catheter for delivery of
ablative agent for multiple repeat ablations over time. The port
1057 obviates the need for repeat invasive procedures and the cost
of catheter placement into the tissue for ablation.
[0277] FIG. 11 illustrates fibroid ablation being performed in a
female uterus by using the ablation device, in accordance with an
embodiment of the present specification. A cross-section of a
female genitourinary tract comprising a uterine fibroid 1111,
uterus 1112, and cervix 1113 is illustrated. The ablation catheter
1115 is passed through the hysteroscope 1114 positioned in the
uterus distal to the fibroid 1111. The ablation catheter 1115 has a
puncturing tip 1120 that helps puncture into the fibroid 1111. The
positioning elements 1116 are deployed to center the catheter in
the fibroid and insulated needles 1117 are passed to pierce the
fibroid tissue 1111. The vapor ablative agent 1118 is passed
through the needles 1117 thus causing ablation of the uterine
fibroid 1111 resulting in shrinkage of the fibroid.
[0278] FIG. 12A illustrates a blood vessel ablation 1240 being
performed by an ablation device, in accordance with one embodiment
of the present specification. The ablation involves replacing the
blood within the vessel with a conductive medium used to distribute
and conduct an ablative agent in the vessel. In one embodiment, the
device used for the ablation comprises a catheter 1220 with a
distal end and a proximal end. The distal end of the catheter 1220
is provided with at least one port 1222 used to remove blood from
the vessel 1240, at least one other port 1224 for injecting a
conductive medium into the vessel 1240, and at least one other port
for delivering an ablative agent 1226 into the vessel 1240. In
various embodiments, each port or any combination of ports is
capable of removing blood, injecting a conductive medium, and/or
delivering an ablative agent, as discussed with reference to the
ablation catheter of FIG. 2F. In one embodiment, the conductive
medium is water. In another embodiment, the conductive medium is
saline. In one embodiment, the ablative agent is steam. The
proximal end of the catheter 1220 is coupled to at least one source
to provide suction, the conductive medium, and the ablative agent.
In one embodiment, the catheter 1220 further includes a sensor 1227
wherein measurements provided by said sensor are used to control
the flow of the ablative agent. In various embodiments, the sensor
is configured to sense any one or combination of blood flow and
ablation parameter, including flow of ablative agent, temperature,
and pressure.
[0279] In one embodiment, a first means for occluding blood flow is
applied proximally to the insertion point of the catheter into the
blood vessel. In one embodiment, the first means comprises a
tourniquet (not shown). In another embodiment, the first means
comprises an intraluminal occlusive element 1228. In one
embodiment, the intraluminal occlusive element 1228 includes a
unidirectional valve 1229 to permit the flow of blood into the
ablation area and to restrict the flow of conductive medium or
ablative agent out of the ablation area. In one embodiment, a
second means for occluding blood flow is applied distally from the
insertion point of the catheter into the blood vessel. The second
means for occluding blood flow acts to prevent blood flow back into
the ablation area and also prevents the passage of conductive
medium and ablative agent beyond the ablation area. In one
embodiment, the second means comprises a tourniquet. In another
embodiment, the second means comprises a second intraluminal
occlusive element. In one embodiment, the second intraluminal
occlusive element includes a unidirectional valve to permit the
flow of blood into the ablation area and to restrict the flow of
conductive medium or ablative agent out of the ablation area.
[0280] FIG. 12B illustrates a blood vessel 1240 ablation being
performed by an ablation device, in accordance with another
embodiment of the present specification. The ablation device is a
coaxial catheter 1230 comprising an internal catheter 1232 and an
external catheter 1234. In one embodiment, the internal catheter
has a distal end with ports 1233 that function in the same manner
as those on the catheter of FIG. 12A and a proximal end coupled to
a source in the same manner as the catheter of FIG. 12A. The
external catheter 1234 is composed of an insulated material and
functions as an insulating sheath over the internal catheter 1232.
In the embodiment pictured in FIG. 12B, the device includes at
least one intraluminal occlusive device 1238 with a unidirectional
valve 1239, coupled to the external catheter 1234 and positioned
proximally, with respect to blood flow, to the ablation device. The
intraluminal occlusive device 1238 functions in the same manner as
that referenced with respect to FIG. 12A. In another embodiment,
the intraluminal occlusive device is not coupled to the external
catheter. In another embodiment, an additional intraluminal device
is positioned distally from the ablation catheter. In various other
embodiments, the flow of blood is stopped by the application of at
least one tourniquet positioned proximally or distally from the
ablation device, or a plurality of tourniquets positioned both
proximally and distally from the ablation device. In one
embodiment, the internal catheter 1232 further includes a sensor
1237 wherein measurements provided by said sensor are used to
control the flow of the ablative agent. In various embodiments, the
sensor is configured to sense any one or combination of blood flow
and ablation parameter, including flow of ablative agent,
temperature, and pressure.
[0281] FIG. 12C is a flow chart listing the steps involved in a
blood vessel ablation process using an ablation catheter, in
accordance with one embodiment of the present specification. At
step 1202, a catheter is inserted into a patient and advanced to
the target blood vessel. The flow of blood into the target vessel
is stopped at step 1204. The catheter tip is then inserted into the
target vessel at step 1206. At step 1208, suction is applied to the
catheter to remove blood from the target vessel. A conductive
medium is then injected into the target vessel through ports on the
catheter at step 1210. Then, at step 1212, an ablative agent is
delivered into the conductive medium to ablate the target vessel.
Suction is applied to the catheter at step 1214 to remove the
conductive medium and ablative agent.
[0282] FIG. 13A illustrates a cyst ablation being performed by an
ablation device, in accordance with one embodiment of the present
specification. The device comprises an ablation catheter 1320
similar to those described with reference to FIGS. 2D-2F. The
catheter 1320 is inserted into the cyst 1340 and the contents of
the cyst are removed via suction through the ports 1333 at the
distal end of the catheter 1320. A conductive medium 1324 is then
injected into the cyst 1340, followed by the delivery of an
ablative agent 1325 to ablate the cyst. In one embodiment, the
catheter 1320 includes a sensor 1328 wherein measurements provided
by said sensor are used to control the flow of the ablative agent.
In one embodiment, the catheter includes echogenic elements to
assist with the placement of the catheter into the cyst under
ultrasonic guidance. In another embodiment, the catheter includes
radio-opaque elements to assist with the placement of the catheter
into the cyst under radiologic guidance.
[0283] FIG. 13B is a flow chart listing the steps involved in a
cyst ablation process using an ablation catheter, in accordance
with one embodiment of the present specification. At step 1302, a
catheter is inserted into a patient and advanced to the target
cyst. The catheter tip is then inserted into the target cyst at
step 1304. At step 1306, suction is applied to the catheter to
remove at least a portion of the contents of the target cyst. A
conductive medium is then injected into the target cyst through
ports on the catheter at step 1308. Then, at step 1310, an ablative
agent is delivered into the conductive medium to ablate the target
cyst. Suction is applied to the catheter at step 1312 to remove the
conductive medium and ablative agent.
[0284] FIG. 14 is a flow chart listing the steps involved in a
solid tumor ablation process using an ablation catheter, in
accordance with one embodiment of the present specification. At
step 1402, a catheter is inserted into a patient and advanced to
the target tumor. The catheter tip is then inserted into the target
tumor at step 1404. A conductive medium is injected into the target
tumor through ports on the catheter at step 1406. Then, at step
1408, an ablative agent is delivered into the conductive medium to
ablate the target tumor. In one embodiment, the catheter includes a
sensor wherein measurements provided by said sensor are used to
control the flow of the ablative agent. In one embodiment, the
catheter includes echogenic elements to assist with the placement
of the catheter into the tumor under ultrasonic guidance. In
another embodiment, the catheter includes radio-opaque elements to
assist with the placement of the catheter into the tumor under
radiologic guidance.
[0285] FIG. 15A illustrates a non-endoscopic device 1520 used for
internal hemorrhoid ablation, in accordance with one embodiment of
the present specification. The device 1520 is inserted into the
rectum of a patient to selectively ablate internal hemorrhoids. The
device 1520 includes a piston 1521 that, when pulled down, creates
suction in a chamber or slot 1522 within the device 1520. The
suction draws a portion of rectal tissue with a hemorrhoid into the
chamber 1522. A port 1524 on the device 1520 is used to provide an
ablative agent 1525 to the chamber 1522 to ablate the hemorrhoid.
In one embodiment, the device is composed of a thermally insulated
material to avoid the transfer of ablative energy to the
surrounding rectal mucosa. In one embodiment, the ablative agent is
steam.
[0286] FIG. 15B is a flow chart listing the steps involved in an
internal hemorrhoid ablation process using a non-endoscopic
ablation device, in accordance with one embodiment of the present
specification. At step 1502, the device described with reference to
FIG. 15A is inserted into the rectum of a patient with internal
hemorrhoids. A piston on the device is actuated to create suction
and draw a portion of hemorrhoid tissue into a slot in the device
at step 1504. Then, at step 1506, an ablative agent is delivered
into the slot via a port on the device to ablate the hemorrhoid.
The piston is released at step 1508 to remove suction, thereby
releasing the portion of rectal tissue.
[0287] FIG. 16A illustrates an endoscopic device 1620 used for
internal hemorrhoid ablation, in accordance with one embodiment of
the present specification. In one embodiment, the device 1620 is
composed of a thermally insulated, transparent material. The device
1620 is mounted to the distal end of an endoscope 1630 and both are
inserted into the patient's rectum. Suction is applied to the
endoscope 1630, drawing a portion of rectal tissue with a
hemorrhoid into a chamber or slot 1622 in the device 1620.
[0288] In one embodiment, an ablative agent 1625 is delivered to
the chamber or slot 1622 through a port 1624 in the device 1620. In
another embodiment, a needle (not shown) is advanced through the
port 1624 and inserted into the rectal submucosa at the position of
the hemorrhoid. An ablative agent is then injected directly into
the hemorrhoid through the needle for selective hemorrhoid
ablation.
[0289] FIG. 16B is a flow chart listing the steps involved in an
internal hemorrhoid ablation process using an endoscopic ablation
device, in accordance with one embodiment of the present
specification. At step 1602, an endoscope with an ablation device
coupled to its distal end is inserted into the rectum of a patient
with internal hemorrhoids. At step 1604, suction is applied to the
endoscope to draw a portion of rectal tissue with a hemorrhoid into
a chamber in the device.
[0290] In one embodiment, at step 1606, an ablative agent is
delivered through a port on the device into the chamber to ablate
the hemorrhoid. Suction is then removed from the endoscope at step
1608 to release the portion of rectal tissue.
[0291] In another embodiment, at step 1610, a needle is advanced
through the port on the device, through the chamber, and into the
hemorrhoid. An ablative agent is then injected at step 1612 through
the needle into the hemorrhoid to ablate said hemorrhoid. At step
1614, the needle is removed from the hemorrhoid. Suction is then
removed from the endoscope at step 1616 to release the portion of
rectal tissue.
[0292] FIG. 17A illustrates a stent 1720 used to provide localized
ablation to a target tissue, in accordance with one embodiment of
the present specification. Similar to conventional stents, the
ablation stent 1720 of the present specification has a compressed,
pre-deployment configuration and an expanded, post-deployment
configuration. The pre-deployment configuration assists with
delivery of the stent and the post-deployment configuration helps
to keep the stent positioned correctly. The stent 1720 is covered
with a conductive membrane 1722 that conducts an ablative agent or
ablative energy from within the stent lumen to the external surface
of the stent, resulting in ablation of the tissue in contact with
the stent 1720. In one embodiment, the membrane 1722 includes at
least one opening 1723 for the transfer of an ablative agent 1724
from the stent lumen to the surrounding tissue. In one embodiment,
the stent 1720 is composed of a wire mesh. In one embodiment, the
membrane 1722 is composed of a thermally conductive material. In
one embodiment, the membrane is composed of silicone. In one
embodiment, the membrane 1722 comprises a plurality of individual
overlapping membranes attached to the stent with intervening
unattached areas through which the ablative agent can escape from
the stent lumen into the surrounding tissues. The unattached
portions of the membrane 1722 act as a unidirectional flap valve
allowing for ablative agent to exit the stent lumen but preventing
the ingrowth of tumor or tissue into the stent 1720.
[0293] FIG. 17B illustrates a catheter 1730 used to deploy, and
provide an ablative agent to, the stent of FIG. 17A. The catheter
1730 has a proximal end and a distal end with a shaft 1731 having a
lumen therebetween. In one embodiment, the catheter 1730 is
composed of a thermally insulated material. The ablative agent 1733
enters the lumen of the catheter from the proximal end 1732. The
catheter 1730 has one or more openings 1735 at the distal end that
allow for the ablative agent 1733 to exit the catheter shaft 1731
and enter the stent lumen. In various embodiments, the catheter
shaft 1731 has one or more positioning elements 1734 to position
the at least one opening 1735 at a desired location inside the
stent lumen. These positioning elements 1734 also act as occlusive
elements to prevent the passage of ablative agent into the adjacent
normal tissue. In various embodiments, optional lumens are
available for the passage of a guidewire or injection of radiologic
contrast material.
[0294] FIG. 17C illustrates the stent 1720 of FIG. 17A working in
conjunction with the catheter 1730 of FIG. 17B. Ablative agent 1733
is provided to the proximal end 1732 of the catheter 1730 and
travels through the catheter shaft 1731 to the distal end of the
catheter 1730. The ablative agent 1733 exits the catheter 1730
through the openings 1735 at the distal end of the catheter 1730.
The ablative agent 1733 is transferred to the surrounding tissues
via the conductive membrane on the stent 1720. The positioning
elements 1734 prevent the escape of ablative agent 1733 from the
proximal and distal ends of the stent 1720.
[0295] FIG. 17D illustrates the stent of FIG. 17A and the catheter
of FIG. 17B positioned in a bile duct 1741 obstructed by a
pancreatic tumor 1740. A stent 1720 is placed in the bile duct to
open the obstruction. The stent 1720 has a thermally conducting
membrane 1722 that allows for transfer of ablative energy from
inside the stent lumen to the surrounding tissue. In one
embodiment, the membrane 1722 has openings to allow for the passage
of the ablative agents from inside the stent lumen to the
surrounding tissue. The catheter 1730 is used to deliver the
catheter at initial deployment and to deliver ablative agent. The
catheter 1730 is also used for subsequent ablation in an already
deployed stent 1720. The ablative agent 1733 is delivered to the
lumen of the stent through at least one opening 1735 in the
catheter shaft. The ablative agent then delivers the ablative
energy from the ablative agent 1733 through the thermally
conducting membrane 1724 or allows for passage of the ablative
agent 1733 through the openings into the surrounding tissue to
ablate the tumor 1740. The catheter has a first positioning element
1734 at the distal end to position the catheter at a fixed distance
from the distal end of the stent 1720. This positioning element is
also used an occlusive member to prevent the flow of the ablative
agent 1733 outside the lumen of the stent into the normal healthy
tissue of the bile duct 1741. In one embodiment, the catheter has a
second positioning element 1735 at the proximal end of the stent
serving similar function as the first positioning element 1734.
[0296] FIG. 17E is a flow chart listing the steps involved in a
hollow tissue or organ ablation process using an ablation stent and
catheter, in accordance with one embodiment of the present
specification. At step 1702, the catheter with the ablation stent
coupled to its distal end is inserted into a hollow tissue of a
patient. The catheter is then advanced at step 1704 to the target
lesion and the stent is deployed. At step 1706, ablative agent is
delivered to the stent lumen via ports on the catheter. The
ablative agent or energy is then conducted to the surrounding
tissue via the conductive membrane on the stent. Once ablation is
completed, the catheter is removed from the patient at step 1708.
If further ablation is needed, the catheter is re-inserted at step
1710 and advanced to the location of the stent. Ablation is then
re-performed at step 1706.
[0297] FIG. 18 illustrates a vapor delivery system using an RF
heater for supplying vapor to the ablation device, in accordance
with an embodiment of the present specification. In an embodiment,
the vapor is used as an ablative agent in conjunction with the
ablation device described in the present specification. RF heater
64 is located proximate a pressure vessel 42 containing a liquid
44. RF heater 64 heats vessel 42, in turn heating the liquid 44.
The liquid 44 heats up and begins to evaporate causing an increase
in pressure inside the vessel 42. The pressure inside vessel 42 can
be kept fairly constant by providing a thermal switch 46 that
controls resistive heater 64. Once the temperature of the liquid 44
reaches a predetermined temperature, the thermal switch 46 shuts
off RF heater 64. The vapor created in pressure vessel 42 may be
released via a control valve 50. As the vapor exits vessel 42, a
pressure drop is created in the vessel resulting in a reduction in
temperature. The reduction of temperature is measured by thermal
switch 46, and RF heater 64 is turned back on to heat liquid 44. In
one embodiment, the target temperature of vessel 42 may be set to
approximately 108.degree. C., providing a continuous supply of
vapor. As the vapor is released, it undergoes a pressure drop,
which reduces the temperature of the vapor to a range of
approximately 90-100.degree. C. As liquid 44 in vessel 42
evaporates and the vapor exits vessel 42, the amount of liquid 44
slowly diminishes. The vessel 42 is optionally connected to
reservoir 43 containing liquid 44 via a pump 49 which can be turned
on by the controller 24 upon sensing a fall in pressure or
temperature in vessel 42, delivering additional liquid 44 to the
vessel 42.
[0298] Vapor delivery catheter 16 is connected to vessel 42 via a
fluid connector 56. When control valve 50 is open, vessel 42 is in
fluid communication with delivery catheter 16 via connector 56.
Control switch 60 may serve to turn vapor delivery on and off via
actuator 48. For example, control switch 60 may physically open and
close the valve 50, via actuator 48, to control delivery of vapor
stream from the vessel 42. Switch 60 may be configured to control
other attributes of the vapor such as direction, flow, pressure,
volume, spray diameter, or other parameters.
[0299] Instead of, or in addition to, physically controlling
attributes of the vapor, switch 60 may electrically communicate
with a controller 24. Controller 24 controls the RF heater 64,
which in turn controls attributes of the vapor, in response to
actuation of switch 60 by the operator. In addition, controller 24
may control valves temperature or pressure regulators associated
with catheter 16 or vessel 42. A flow meter 52 may be used to
measure the flow, pressure, or volume of vapor delivery via the
catheter 16. The controller 24 controls the temperature and
pressure in the vessel 42 and the time, rate, flow, and volume of
vapor flow through the control valve 50. These parameters are set
by the operator 11. The pressure created in vessel 42, using the
target temperature of 108.degree. C., may be in the order of 25
pounds per square inch (psi) (1.72 bars).
[0300] FIG. 19 illustrates a vapor delivery system using a
resistive heater for supplying vapor to the ablation device, in
accordance with an embodiment of the present specification. In an
embodiment, the generated vapor is used as an ablative agent in
conjunction with the ablation device described in the present
specification. Resistive heater 40 is located proximate a pressure
vessel 42. Vessel 42 contains a liquid 44. Resistive heater 40
heats vessel 42, in turn heating liquid 44. Accordingly, liquid 44
heats and begins to evaporate. As liquid 44 begins to evaporate,
the vapor inside vessel 42 causes an increase in pressure in the
vessel. The pressure in vessel 42 can be kept fairly constant by
providing a thermal switch 46 that controls resistive heater 40.
When the temperature of liquid 44 reaches a predetermined
temperature, thermal switch 46 shuts off resistive heater 40. The
vapor created in pressure vessel 42 may be released via a control
valve 50. As the vapor exits vessel 42, vessel 42 experiences a
pressure drop. The pressure drop of vessel 42 results in a
reduction of temperature. The reduction of temperature is measured
by thermal switch 46, and resistive heater 40 is turned back on to
heat liquid 44. In one embodiment, the target temperature of vessel
42 may be set to approximately 108.degree. C., providing a
continuous supply of vapor. As the vapor is released, it undergoes
a pressure drop, which reduces the temperature of the vapor to a
range of approximately 90-100.degree. C. As liquid 44 in vessel 42
evaporates and the vapor exits vessel 42, the amount of liquid 44
slowly diminishes. The vessel 42 is connected to another vessel 43
containing liquid 44 via a pump 49 which can be turned on by the
controller 24 upon sensing a fall in pressure or temperature in
vessel 42 delivering additional liquid 44 to the vessel 42.
[0301] Vapor delivery catheter 16 is connected to vessel 42 via a
fluid connector 56. When control valve 50 is open, vessel 42 is in
fluid communication with delivery catheter 16 via connector 56.
Control switch 60 may serve to turn vapor delivery on and off via
actuator 48. For example, control switch 60 may physically open and
close the valve 50, via actuator 48, to control delivery of vapor
stream from the vessel 42. Switch 60 may be configured to control
other attributes of the vapor such as direction, flow, pressure,
volume, spray diameter, or other parameters. Instead of, or in
addition to, physically controlling attributes of the vapor, switch
60 may electrically communicate with a controller 24. Controller 24
controls the resistive heater 40, which in turn controls attributes
of the vapor, in response to actuation of switch 60 by the
operator. In addition, controller 24 may control valves temperature
or pressure regulators associated with catheter 16 or vessel 42. A
flow meter 52 may be used to measure the flow, pressure, or volume
of vapor delivery via the catheter 16. The controller 24 controls
the temperature and pressure in the vessel 42 as well as time,
rate, flow, and volume of vapor flow through the control valve 50.
These parameters are set by the operator 11. The pressure created
in vessel 42, using the target temperature of 108.degree. C., may
be on the order of 25 pounds per square inch (psi) (1.72 bars).
[0302] FIG. 20 illustrates a vapor delivery system using a heating
coil for supplying vapor to the ablation device, in accordance with
an embodiment of the present specification. In an embodiment, the
generated vapor is used as an ablative agent in conjunction with
the ablation device described in the present specification. The
vapor delivery system includes a conventional generator 2000 that
is commonly used in operating rooms to provide power to specialized
tools, i.e., cutters. The generator 2000 is modified to include an
integrated liquid reservoir 2001. In one embodiment, the reservoir
2001 is filled with room temperature pure water. The reservoir 2001
portion of the generator 2000 is connected to the heating component
2005 via a reusable active cord 2003. In one embodiment, the
reusable active cord 2003 may be used up to 200 times. The cord
2003 is fixedly attached via connections at both ends to withstand
operational pressures, and preferably a maximum pressure, such that
the cord does not become disconnected. In one embodiment, the
connections can resist at least 1 atm of pressure. In one
embodiment, the connections are of a luer lock type. The cord 2003
has a lumen through which liquid flows to the heating component
2005. In one embodiment, the heating component 2005 contains a
coiled length of tubing 2006. As liquid flows through the coiled
tubing 2006, it is heated by the surrounding heating component 2005
in a fashion similar to a conventional heat exchanger. As the
liquid is heated, it becomes vaporized. The heating component
contains a connector 2007 that accommodates the outlet of vapor
from the coiled tubing 2006. One end of a single use cord 2008
attaches to the heating component 2005 at the connector 2007. The
connector 2007 is designed to withstand pressures generated by the
vapor inside the coiled tubing 2006 during operation. In one
embodiment, the connector 2007 is of a luer lock type. An ablation
device 2009 is attached to the other end of the single use cord
2008 via a connection able to withstand the pressures generated by
the system. In one embodiment, the ablation device is integrated
with a catheter. In another embodiment, the ablation device is
integrated with a probe. The single use cord 2008 has a specific
luminal diameter and is of a specific length to ensure that the
contained vapor does not condense into liquid while simultaneously
providing the user enough slack to operate. In addition, the single
use cord 2008 provides sufficient insulation so that personnel will
not suffer burns when coming into contact with the cord. In one
embodiment, the single use cord has a luminal diameter of less than
3 mm, preferably less than 2.6 mm, and is longer than 1 meter in
length.
[0303] In one embodiment, the system includes a foot pedal 2002 by
which the user can supply more vapor to the ablation device.
Depressing the foot pedal 2002 allows liquid to flow from the
reservoir 2001 into the heating component 2005 where it changes
into vapor within the coiled tubing 2006. The vapor then flows to
the ablation device via the single use tube 2008. The ablation
device includes an actuator by which the user can open small ports
on the device, releasing the vapor and ablating the target
tissue.
[0304] FIG. 21 illustrates the heating component 2105 and coiled
tubing 2106 of the heating coil vapor delivery system of FIG. 20,
in accordance with an embodiment of the present specification.
Liquid arrives through a reusable active cord (not shown) at a
connection 2102 on one side of the heating component 2105. The
liquid then travels through the coiled tubing 2106 within the
heating component 2105. The coiled tubing is composed of a material
and configured specifically to provide optimal heat transfer to the
liquid. In one embodiment, the coiled tubing 2106 is copper. The
temperature of the heating component 2105 is set to a range so that
the liquid is converted to vapor as it passes through the coiled
tubing 2106. In one embodiment, the temperature of the heating
component 2105 can be set by the user through the use of a
temperature setting dial 2108. In one embodiment, the heating
component contains an on/off switch 2109 and is powered through the
use of an attached AC power cord 2103. In another embodiment, the
heating component receives power through an electrical connection
integrated into and/or facilitated by the active cord connection to
the reservoir. The vapor passes through the end of the coiled
tubing 2106 and out of the heating component 2105 through a
connector 2107. In one embodiment, the connector 2107 is located on
the opposite side of the heating component 2105 from the inlet
connection 2102. A single use cord (not shown) attaches to the
connector 2107 and supplies vapor to the ablation device.
[0305] FIG. 22A illustrates the unassembled interface connection
between the ablation device 2208 and the single use cord 2201 of
the heating coil vapor delivery system of FIG. 20, in accordance
with an embodiment of the present specification. In this
embodiment, the ablation device 2208 and single use cord 2201 are
connected via a male-to-male double luer lock adapter 2205. The end
of the single use cord 2201 is threaded to form a female end 2202
of a luer lock interface and connects to one end of the adapter
2205. The ablation device 2208 includes a small protrusion at its
non-operational end which is also threaded to form a female end
2207 of a luer lock interface and connects to the other end of the
adapter 2205. The threading luer lock interface provides a secure
connection and is able to withstand the pressures generated by the
heating coil vapor delivery system without becoming
disconnected.
[0306] FIG. 22B illustrates the assembled interface connection
between the ablation device 2208 and the single use cord 2201 of
the heating coil vapor delivery system of FIG. 20, in accordance
with an embodiment of the present specification. The male-to-male
double luer lock adapter 2205 is pictured securing the two
components together. The double luer lock interface provides a
stable seal, allows interchangeability between ablation devices,
and enables users to quickly replace single use cords.
[0307] FIG. 23 illustrates a vapor ablation system using a heater
or heat exchange unit for supplying vapor to the ablation device,
in accordance with another embodiment of the present specification.
In the pictured embodiment, water for conversion to vapor is
supplied in a disposable, single use sterile fluid container 2305.
The container 2305 is sealed with a sterile screw top 2310 that is
punctured by a needle connector 2315 provided on a first end of a
first filter member 2320. The second end of the first filter member
2320, opposite the first end, is connected to a pump 2325 for
drawing the water from the fluid container 2305, through the first
filter member 2320, and into the heater or heat exchange unit 2330.
The system includes a microcontroller or microprocessor 2335 for
controlling the actions of the pump 2325 and heater or heat
exchange unit 2330. The heater or heat exchange unit 2330 converts
the water into vapor (steam). The increase in pressure generated
during the heating step drives the vapor through an optional second
filter member 2340 and into the ablation catheter 2350. In one
embodiment, the heater or heat exchange unit 2330 includes a
one-way valve at its proximal end to prevent the passage of vapor
back toward the pump 2325. In various embodiments, optional sensors
2345 positioned proximate the distal end of the catheter 2350
measure one or more of temperature, pressure, or flow of vapor and
transmit the information to the microcontroller 2335, which in turn
controls the rate of the pump 2325 and the level of vaporizing
energy provided by the heater or heat exchange unit 2330.
[0308] FIG. 24 illustrates the fluid container 2405, first filter
member 2420, and pump 2425 of the vapor ablation system of FIG. 23.
As can be seen in the pictured embodiment, the system includes a
water-filled, disposable, single use sterile fluid container 2405
and a pump 2425 with a first filter member 2420 disposed
therebetween. The first filter member 2420 is connected to the
container 2405 and pump 2425 by two first and second lengths of
sterile tubing 2407, 2422 respectively, and includes a filter for
purifying the water used in the ablation system.
[0309] FIGS. 25 and 26 illustrate first and second views
respectively, of the fluid container 2505, 2605, first filter
member 2520, 2620, pump 2525, 2625, heater or heat exchange unit
2530, 2630, and microcontroller 2535, 2635 of the vapor ablation
system of FIG. 23. The container 2505, 2605 is connected to the
first filter member 2520, 2620 by a first length of sterile tubing
2507, 2607 and the first filter member 2520, 2620 is connected to
the pump 2525, 2625 by a second length of sterile tubing 2522,
2622. A third length of sterile tubing 2527, 2627 connects the pump
2525, 2625 to the heater or heat exchange unit 2530, 2630. The
microcontroller 2535, 2635, is operably connected to the pump 2525,
2625 by a first set of control wires 2528, 2628 and to the heater
or heat exchange unit 2530, 2630 by a second set of control wires
2529, 2629. The arrows 2501, 2601 depict the direction of the flow
of water from the container 2505, 2605, through the first filter
member 2520, 2620 and pump 2525, 2625 and into the heater or heat
exchange member 2530, 2630 where it is converted to vapor. Arrow
2531, 2631 depicts the direction of flow of vapor from the heater
or heat exchange unit 2530, 2630 into the ablation catheter (not
shown) for use in the ablation procedure.
[0310] FIG. 27 illustrates the unassembled first filter member 2720
of the vapor ablation system of FIG. 23, depicting the filter 2722
positioned within. In one embodiment, the first filter member 2720
includes a proximal portion 2721, a distal portion 2723, and a
filter 2722. The proximal portion 2721 and distal portion 2723
secure together and hold the filter 2722 within. Also depicted in
FIG. 27 are the disposable, single use sterile fluid container 2705
and the first length of sterile tubing 2707 connecting the
container 2705 to the proximal portion 2721 of the first filter
member 2720.
[0311] FIG. 28 illustrates one embodiment of the microcontroller
2800 of the vapor ablation system of FIG. 23. In various
embodiments, the microcontroller 2800 includes a plurality of
control wires 2828 connected to the pump and heater or heat
exchange unit for controlling said components and a plurality of
transmission wires 2847 for receiving flow, pressure, and
temperature information from optional sensors positioned proximate
the distal end of the ablation catheter.
[0312] FIG. 29 illustrates one embodiment of a catheter assembly
2950 for use with the vapor ablation system of FIG. 23. Vapor is
delivered from the heater or heat exchange unit to the catheter
assembly 2950 via a tube 2948 attached to the proximal end of a
connector component 2952 of the assembly 2950. A disposable
catheter 2956 with a fixedly attached disposable length of flexible
tubing 2958 at its distal end is fitted over the connector
component 2952. A second filter member 2954 is positioned between
the connector component 2952 and the disposable catheter 2956 for
purifying the vapor supplied by the heater or heat exchange unit.
The connector component 2952 includes two washers 2953 positioned
apart a short distance at its distal end to engage the overlaying
disposable catheter 2956 and form a double-stage seal, thereby
preventing vapor leakage between the components. Once the
disposable catheter 2956 has been fitted to the distal end of the
connector component 2952, a catheter connector 2957 is slid over
the disposable flexible tubing 2958 and disposable catheter 2956
and is then snapped into place onto the connector component 2952.
The catheter connector 2957 acts to keep the disposable catheter
2956 in place and also assists in preventing vapor leakage. In
various embodiments, the disposable flexible tubing 2958 includes
one or more holes or ports 2959 at or proximate its distal end for
the delivery of ablative vapor to target tissues.
[0313] FIG. 30 illustrates one embodiment of a heat exchange unit
3030 for use with the vapor ablation system of FIG. 23. The heat
exchange unit 3030 comprises a length of coiled tubing 3035
surrounded by a heating element 3034. Water 3032 enters the coiled
tubing 3035 of the heat exchange unit 3030 at an entrance port 3033
proximate a first end of said heat exchange unit 3030. As the water
3032 flows within the coiled tubing 3035, it is converted into
vapor (steam) 3038 by the heat emanating from said coiled tubing
3035 which has been heated by the heating element 3034. The vapor
3038 exits the coiled tubing 3035 of the heat exchange unit 3030 at
an exit port 3037 proximate a second end of said heat exchange unit
3030 and is then delivered to the ablation catheter (not shown) for
use in the ablation procedure.
[0314] FIG. 31A illustrates another embodiment of a heat exchange
unit 3160 for use with the vapor ablation system of the present
specification. In the pictured embodiment, the heat exchange unit
3160 comprises a cylindrically shaped, pen sized `clamshell` style
heating block. The heating block of the heat exchange unit 3160
includes a first half 3161 and a second half 3162 fixedly attached
by a hinge 3163 along one side, wherein the halves 3161, 3162 fold
together and connect on the opposite side. In one embodiment, the
sides of the halves opposite the sides with the hinge include a
clasp for holding the two halves together. In one embodiment, one
of the halves includes a handle 3164 for manipulating the heat
exchange unit 3160. When the halves are folded together, the heat
exchange unit 3160 snugly envelopes a cylindrically shaped catheter
fluid heating chamber 3151 attached to, inline and in fluid
communication with, the proximal end of the ablation catheter 3150.
Each half 3161, 3162 of the heat exchange unit 3160 includes a
plurality of heating elements 3165 for heating the block. In
various embodiments, heat is transferred from the heating elements
3165 to the catheter fluid heating chamber 3151 using resistive or
RF heating. The positioning and fit of the heating block place it
in close thermal contact with the catheter fluid heating chamber
3151. When in operation, the heating elements 3165 heat the heating
block which transfers heat to the catheter fluid heating chamber
3151, which in turn heats the water inside the chamber 3151,
converting said water to vapor. The heating block does not directly
contact the water. In one embodiment, the catheter fluid heating
chamber 3151 comprises a plurality of linear indentations 3191
stretching along the length of the component and in parallel with
the heating elements 3165. Upon closing the halves 3161, 3162, the
heating elements 3165, which optionally protrude from the internal
surfaces of the halves 3161, 3162 contact, and fit within, the
linear indentations 3191. This also increases the surface area of
contact between the heating block and the heating chamber,
improving the efficiency of heat exchange.
[0315] A luer fitting coupler 3149 is provided at the proximal end
of the catheter fluid heating chamber 3151 for connecting a tube
supplying sterile water. In one embodiment, a one-way valve is
included at the proximal end of the catheter fluid heating chamber
3151, distal to the luer fitting 3149, to prevent the passage of
vapor under pressure toward the water supply.
[0316] FIG. 31B illustrates another embodiment of a heat exchange
unit 3170 for use with the vapor ablation system of the present
specification. The heat exchange unit 3170 of FIG. 31B functions
similarly to the heat exchange unit 3160 pictured in FIG. 31A.
However, rather than having an open design capable of opening and
closing, heat exchange unit 3170 has a closed design and is
configured to slide over the catheter fluid heating chamber 3151.
In one embodiment, the heat exchange unit 3170 includes a handle
3174 for manipulation of said unit about the catheter 3150.
[0317] As described above, the catheter fluid heating chamber is
designed as part of the ablation catheter and, along with the
remainder of the catheter, is single use and disposable. In another
embodiment, the chamber is reusable, in which case the luer fitting
is positioned in between the catheter shaft and the chamber. The
heating block is designed to be axially aligned with the heating
chamber when in use, is reusable, and will not be damaged in the
event that it falls to the floor. In one embodiment, the weight and
dimensions of the heating block are designed such that it can be
integrated into a pen-sized and shaped handle of the ablation
catheter. The handle is thermally insulated to prevent injury to
the operator.
[0318] In one embodiment, the heating block receives its power from
a console which is itself line powered and designed to provide
700-1000 W of power, as determined by the fluid vaporization rate.
The heating block and all output connections are electrically
isolated from line voltage. In one embodiment, the console includes
a user interface allowing adjustment of power with a commensurate
fluid flow rate. In addition, in one embodiment, a pump, such as a
syringe pump, is used to control the flow of fluid to the heating
chamber and heating element. In one embodiment, the volume of the
syringe is at least 10 ml and is ideally 60 ml.
[0319] In the above embodiment, the catheter to be used with the
vapor ablation system is designed using materials intended to
minimize cost. In one embodiment, the tubing used with the catheter
is able to withstand a temperature of at least 125.degree. C. and
can flex through an endoscope's bend radius (approximately 1 inch)
without collapse. In one embodiment, the section of the catheter
that passes through an endoscope is 7 French (2.3 mm) diameter and
has a minimum length of 215 cm. In one embodiment, thermal
resistance is provided by the catheter shaft material which shields
the endoscope from the super-heated vapor temperature. In one
embodiment, the heat exchange unit is designed to interface
directly with, or in very close proximity to, an endoscope's biopsy
channel to minimize the likelihood of a physician handling heated
components. Having the heat exchange unit in close proximity to the
endoscope handle also minimizes the length of the catheter through
which the vapor needs to travel, thus minimizing heat loss and
premature condensation.
[0320] In various embodiments, other means are used to heat the
fluid within the catheter fluid heating chamber. FIG. 32A
illustrates the use of induction heating to heat a chamber 3205.
When an alternating electric current 3202 is passed through a coil
3207 of wire within the chamber 3205, the coil 3207 creates a
magnetic field 3209. Magnetic lines of flux 3210 of the magnetic
field 3209 cut through the air around the coil 3207. When the
chamber 3205 is composed of a ferrous material, such as, iron,
stainless steel, or copper, electrical currents known as eddy
currents 3215 are induced to flow in the chamber 3205 as a result
of the presence of the alternating current 3202 and magnetic field
3209 with lines of flux 3210. The eddy currents 3215 cause
localized heating of the chamber 3205. When the chamber 3205 is
filled with a fluid, such as water, the heat is transferred from
the chamber to the fluid inside, resulting in vaporization of said
fluid. In the embodiment depicted in FIG. 32A, the coil 3207 is
looped about the chamber 3205 with four loops and spaced a distance
away from said chamber 3205 to assist with visualization. The
design of the chamber and coil in FIG. 32A depicts only one
possible embodiment and is not intended to be limiting. Those
skilled in the art will understand many different design
configurations are possible with respect to the chamber and coil.
In various embodiments, the coil includes at least one loop about
the chamber and is looped about said chamber such that the coil is
in physical contact with said chamber. In other embodiments, the
coil includes at least one loop about the chamber and is looped
about said chamber such that the coil is spaced away a specific
distance from said chamber with a layer of air or other insulating
material between said coil and said chamber. In various
embodiments, the loops of the coil are arranged closely together
such that they are in contact with one another. In other
embodiments, the loops of the coil are arranged with a specific
distance between one another. In one embodiment, the loops of the
coil extend along the entire length of the chamber. In various
embodiments, the loops of the coil extend beyond the length of the
chamber. In other embodiments, the loops of the coil extend along a
portion of the length of the chamber that is less than the
chamber's total length.
[0321] FIG. 32B is a flow chart listing the steps involved in using
induction heating to heat a chamber. At step 3252, a metal coil is
placed about a chamber composed of a ferromagnetic material such
that the coil surrounds the chamber. Then, at step 3254, the
chamber is filled with a fluid via a proximal inlet port on said
chamber. At step 3256, an alternating current is provided to the
coil, creating a magnetic field in the area surrounding the
chamber. The magnetic field induces electric (eddy) current flow in
the ferromagnetic material which heats the chamber. The heat is
transferred to the fluid inside the chamber and vaporizes the
fluid. The vaporized fluid exits the chamber via the distal outlet
port.
[0322] FIG. 33A illustrates one embodiment of a coil 3370 used with
induction heating in the vapor ablation system of the present
specification. A section of the coil 3370 has been cut away to
assist with visualization. The coil 3370 is positioned surrounding
the catheter fluid heating chamber 3351. An alternating current
3302 passing through the coil 3370 creates a magnetic field which
induces eddy currents 3315 to flow in the chamber 3370 as described
above. The flow of eddy currents 3315 results in heating of the
catheter fluid heating chamber 3351. The heated chamber heats the
fluid within, converting it into a vapor, which passes into the
catheter 3350 for use in the ablation procedure. The coil 3370
itself does not heat, making it safe to touch. A luer fitting
coupler 3349 is provided at the proximal end of the catheter fluid
heating chamber 3351 for connecting a tube supplying sterile water.
In one embodiment, a one-way valve (not shown) is included at the
proximal end of the catheter fluid heating chamber 3351, distal to
the luer fitting 3349, to prevent the passage of vapor toward the
water supply. In one embodiment, thermal insulating material (not
shown) is positioned between the coil 3370 and the heating chamber
3351. In another embodiment, the chamber 3351 is suspended in the
center of the coil 3370 with no physical contact between the two.
In this embodiment, the intervening air acts as a thermally
insulating material. The design of the chamber is optimized to
increase its surface area to maximize contact and heat transfer, in
turn resulting in more efficient vapor generation. In one
embodiment, the coil 3370 is constructed in a `clamshell` style
design, similar to the heat exchange unit 3160 depicted in FIG.
31A, and opens and closes about the heating chamber 3351. In
another embodiment, the coil 3370 is constructed in a closed style
design, similar to the heat exchange unit 3170 depicted in FIG.
31B, and slides over the heating chamber 3351.
[0323] In various embodiments, the induction heating systems and
structures described in FIGS. 32A and 33A can be applied to any of
the fluid chambers shown in any of the disclosed embodiments of the
present specification.
[0324] FIG. 33B illustrates one embodiment of a catheter handle
3372 used with induction heating in the vapor ablation system of
the present specification. The handle 3372 is thermally insulated
and incorporates an induction coil. In one embodiment, the handle
3372 includes an insulated tip 3373 at its distal end that engages
with an endoscope channel after the catheter is inserted into the
endoscope. The catheter 3350 is connected to the heating chamber
3351 which in turn is connected with the pump via an insulated
connector 3374. In one embodiment, the heating chamber 3351 length
and diameter are less than those of the handle 3372 and the
induction coil, thus the heating chamber 3351 can slide inside the
handle 3372 in a coaxial fashion while maintaining a constant
position within the magnetic field generated by the induction coil.
The operator can manipulate the catheter 3350 by grasping on the
insulated connector 3374 and moving it in and out of the handle
3372 which in turn moves the catheter tip in and out of the distal
end of the endoscope. In this design, the heated portions of the
catheter 3350 are within the channel of the endoscope and in the
insulated handle 3372, thus not coming into contact with the
operator at anytime during the operation. An optional sensor 3375
on the insulated tip 3373 can sense when the catheter is not
engaged with the endoscope and temporarily disable the heating
function of the catheter to prevent accidental activation and
thermal injury to the operator. With respect to FIG. 33B, the
catheter 3350 and heating chamber 3351 are the heated components of
the system while the handle 3372, insulated tip 3373, and insulated
connector 3374 are the cool components and therefore safe to touch
by the user.
[0325] FIGS. 34A and 34B are front and longitudinal view cross
sectional diagrams respectively, illustrating one embodiment of a
catheter 3480 used with induction heating in the vapor ablation
system of the present specification. The catheter 3480 includes an
insulated handle 3486 that contains a heating chamber 3451 and an
induction coil 3484. The heating chamber 3451 includes a luer lock
3449 at its proximal end. The luer lock 3449 has a one-way valve
that prevents the backward flow of vapor from the chamber 3451.
Vaporization of fluid in the chamber results in volume expansion
and an increase in pressure which pushes the vapor out of the
chamber 3449 and into the catheter body. The induction coil 3484
includes a wire 3486 that extends from the proximal end of the
catheter 3480 for the delivery of an alternating current. The
handle 3486 is connected to the catheter 3480 with an outer
insulating sheath 3481 made of a thermally insulating material.
[0326] In various embodiments, the insulating material is polyether
ether ketone (PEEK), polytetrafluoroethylene (PTFE), fluorinated
ethylene propylene (FEP), polyether block amide (PEBA), polyimide,
or a similar material. In various embodiments, optional sensors
3487 positioned proximate the distal end of the catheter 3480
measure one or more of temperature, pressure, or flow of vapor and
transmit the information to a microprocessor, which in turn
controls the flow rate of the fluid and the level of vaporizing
energy provided to the chamber 3451. The microcontroller adjusts
fluid flow rate and chamber temperature based on the sensed
information, thereby controlling the flow of vapor and in turn, the
flow of ablative energy to the target tissue.
[0327] In one embodiment, the catheter 3480 includes an inner
flexible metal skeleton 3483. In various embodiments, the skeleton
3483 is composed of copper, stainless steel, or another ferric
material. The skeleton 3483 is in thermal contact with the heating
chamber 3451 so that the heat from the chamber 3451 is passively
conducted through the metal skeleton 3483 to heat the inside of the
catheter 3480, thus maintaining the steam in a vaporized state and
at a relatively constant temperature. In various embodiments, the
skeleton 3483 extends through a particular portion or the entire
length of the catheter 3480. In one embodiment, the skeleton 3483
includes fins 3482 at regular intervals that keep the skeleton 3483
in the center of the catheter 3480 for uniform heating of the
catheter lumen.
[0328] In another embodiment, as seen in FIG. 34C, the catheter
includes an inner metal spiral 3488 in place of the skeleton. In
yet another embodiment, as seen in FIG. 34D, the catheter includes
an inner metal mesh 3489 in place of the skeleton. Referring to
FIGS. 34B, 34C, and 34D simultaneously, water 3432 enters the luer
lock 3449 at a predetermined rate. It is converted to vapor 3438 in
the heating chamber 3451. The metal skeleton 3483, spiral 3488, and
mesh 3489 all conduct heat from the heating chamber 3451 into the
catheter lumen to prevent condensation of the vapor in the catheter
and insure that ablating vapor will exit the catheter from one or
more holes or ports at its distal end.
[0329] FIG. 35 illustrates one embodiment of a heating unit 3590
using microwaves 3591 to convert fluid to vapor in the vapor
ablation system of the present specification. The microwaves 3591
are directed toward the catheter fluid heating chamber 3551,
heating the chamber 3551 and converting the fluid within into
vapor. The vapor passes into the catheter 3550 for use in the
ablation procedure. A luer fitting coupler 3549 is provided at the
proximal end of the catheter fluid heating chamber 3551 for
connecting a tube supplying sterile water. In one embodiment, a
one-way valve (not shown) is included at the proximal end of the
catheter fluid heating chamber 3551, distal to the luer fitting
3549, to prevent the passage of vapor toward the water supply.
[0330] In various embodiments, other energy sources, such as, High
Intensity Focused Ultrasound (HIFU) and infrared energy, are used
to heat the fluid in the catheter fluid heating chamber.
[0331] FIG. 36A is illustrates a catheter assembly having an inline
chamber 3610 for heat transfer in accordance with one embodiment of
the present specification and FIG. 36B illustrates the catheter
assembly of FIG. 36A including an optional handle 3630. Referring
to FIGS. 36A and 36B simultaneously, the assembly includes a
catheter 3605 having an elongate body with a lumen within, a
proximal end, and a distal end. A first inline chamber 3610, having
an elongate body with a lumen within, a proximal end and a distal
end, is attached at its distal end to the proximal end of the
catheter 3605. In various embodiments, the first inline chamber
3610 is composed of a ferromagnetic substance or a thermally
conducting substance. The lumen of the catheter 3605 is in fluid
communication with the lumen of the first inline chamber 3610. A
second inline chamber 3620, having an elongate body with a lumen
within, a proximal end and a distal end, is attached at its distal
end to the proximal end of the first inline chamber 3610. The
second inline chamber 3620 is filled with a fluid. The lumen of the
first inline chamber 3610 is in fluid communication with the lumen
of the second inline chamber 3620. In one embodiment, the
connection between the first inline chamber 3610 and the second
inline chamber 3620 includes an optional valve 3615 to control the
flow of fluid from said second inline chamber 3620 to said first
inline chamber 3610.
[0332] The catheter assembly is connected to a pump which controls
the flow of fluid from said second inline chamber 3620 to said
first inline chamber 3610. In one embodiment, the pump is a syringe
pump that engages a piston 3625 within and proximate the proximal
end of the second inline chamber 3620 which pushes the fluid from
said second inline chamber 3620 into said first inline chamber 3610
at a predefined rate. In one embodiment, the pump is controlled by
a microprocessor. In one embodiment, the microprocessor receives
optional information from sensors in the catheter or in the tissue
to control the flow of the fluid from chamber 3620 into chamber
3610. In various embodiments, the fluid is heated in chamber 3610
using any conventional methods of heating, including those
discussed above. In various embodiments, the first inline chamber
3610 has more than one channel for the flow of the fluid to
increase the surface area of contact of the fluid with the chamber
3610 surfaces, improving the efficiency of heating the fluid. In
one embodiment, the first inline chamber 3610 is optionally covered
by a material that is a poor thermal conductor, preventing the
escape of heat from the chamber 3610. This embodiment is preferred
if the method of heating is electromagnetic induction. In one
embodiment, referring to FIG. 36B, the catheter 3605 includes an
optional handle 3630 allowing for safe maneuvering of the catheter
assembly. In one embodiment, the handle 3630 is composed of a
material that is a poor thermal conductor to prevent thermal injury
to the operator from over-heating of the catheter 3605.
[0333] It is desirable to have an integrated system as it
eliminates any connections that may malfunction or leak causing
system malfunction and/or injury to a patient or an operator.
Additionally, it is desirable to have the fluid and heating
chambers included as parts of the catheter assembly which
eliminates problems encountered with corrosion of the metal in the
heating chamber with multiple uses and also ensures sterility of
the ablation fluid with multiple uses.
[0334] FIG. 36C illustrates the catheter assembly of FIG. 36B
connected to a generator 3640 having a heating element 3650 and a
pump 3645, in accordance with one embodiment of the present
specification. The catheter connects to the generator 3640 with the
heating element 3650 and pump 3645. In various embodiments, the
heating element 3650 is a resistive heater, an RF heater, a
microwave heater, or an electromagnetic heater. The piston 3625
engages with the pump 3645. On initiating therapy, the pump 3645
pushes on the piston 3625 to deliver fluid from the second inline
chamber 3620 into the first inline chamber 3610 through valve 3615
at a predetermined rate. In one embodiment, the fluid is water. The
water is heated in the first inline chamber 3610 to be converted
into vapor. As the vapor expands it is pushed out through the
distal end of the catheter 3605 to be delivered to the desired
tissue for ablation. In the pictured embodiment, the catheter
assembly includes a handle 3630 for manipulating the catheter 3605
which has been filled with heated water vapor.
[0335] As stated above, it is desirable to have a large surface
area within the heating chamber for contact heating of the ablative
agent. This is accomplished by having multiple small channels
within the heating chamber. In various embodiments, the channels
are created by packing the chamber with metal tubes, metal beads,
or metal filings, all of which significantly increase the surface
area for contact heating. FIG. 37A illustrates a heating chamber
3705 packed with metal tubes 3707 in accordance with one embodiment
of the present specification. FIG. 37B illustrates a heating
chamber 3715 packed with metal beads 3717 in accordance with one
embodiment of the present specification. FIG. 37C illustrates a
heating chamber 3725 packed with metal filings 3727 in accordance
with one embodiment of the present specification. In various
embodiments, the heating chamber 3705, 3715, 3725 and its channels
3707, 3717, 3727 are made of a ferromagnetic material or a
thermally conducting material and the ablative agent 3708, 3718,
3728 flows through these channels 3707, 3717, 3727 where it is
heated rapidly and in an efficient manner.
[0336] In one embodiment, the heat chamber and its channels are
made of a material having a specific Curie point or Curie
temperature (T.sub.c). These materials undergo a phase change from
ferromagnetic to paramagnetic when subjected to their T.sub.c. If
such a material is inside an electromagnet that is driven with AC
power of several kHz, the material exhibits large magnetic
hysteresis losses and is ferromagnetic below T.sub.c, which results
in Joule heating. At T.sub.c, the material abruptly loses its soft
magnetic property, its magnetic hysteresis vanishes and the Joule
heating is reduced by several orders of magnitude. As the material
cools below T.sub.c, the hysteresis losses increase again, heating
resumes and the cycle is repeated.
[0337] This physical phenomenon is used to develop a heating device
with an intrinsic "thermostat". In essence, such an element absorbs
the energy from the electromagnetic field precisely as needed to
maintain its temperature at T.sub.c but will not heat above it,
making it inherently failsafe from overheating. Moreover, areas of
the device that are cooled due to heat transfer to the surrounding
tissue immediately reheat while areas where heat has not been
transferred to the tissue cease heating.
[0338] T.sub.c can easily be adjusted by selecting the ratios of
low-cost base metals in the material. Industry standard soft
magnetic nickel-iron alloys containing from about 28% to 70% nickel
(Ni) have Curie temperatures ranging from room temperature to
600.degree. C. For target temperatures of 100.degree.
C.-120.degree. C., the class of low-nickel alloys containing 30% Ni
are most suitable. For higher temperatures, higher Ni
concentrations are desirable. Small additions of copper (Cu),
silicon (Si), manganese (Mn), or chromium (Cr) allow for alloying
of very precise Curie temperatures. For example, several low Curie
temperature iron-chromium-nickel-manganese (Fe--Cr--Ni--Mn) alloys
are listed in Table 3 below.
TABLE-US-00003 TABLE 3 Chemical Composition [wt. %] T.sub.c
[.degree. C.] Cr4Ni32Fe62Mn1.5Si0.5 55 Cr4Ni33Fe62.5Si0.5 120
Cr10Ni33Fe53.5Mn3Si0.5 10 Cr11Ni35Fe53.5Si0.5 66
[0339] In order to have high insulation properties, the catheters
described above require increased wall thickness. The increased
wall thickness would decrease the size of the lumen and increase
the resistance to flow of the ablative agent. Therefore, in various
embodiments, the inner surface of the catheter includes a groove to
decrease the resistance to flow of an ablative agent. FIG. 38A
illustrates a cross-sectional view of one embodiment of a catheter
3805 having an internal groove 3810 to decrease flow resistance and
FIG. 38B illustrates an on-end view of one embodiment of a catheter
3815 having an internal groove 3820 to decrease flow
resistance.
[0340] In another embodiment, the resistance to flow is reduced by
sending a sound wave down the catheter bore along with the ablative
agent to create sympathetic resonances. The sympathetic resonances
create a channeling effect where friction with the vessel wall is
dramatically reduced.
[0341] To improve the thermal insulation property of the catheter,
a dual layered catheter can be formed with a thin layer of air or
insulating fluid between the two catheter layers. In one
embodiment, the insulating layer of air or fluid is circulated back
into the power generator to facilitate heat transfer into the
generator rather than through the catheter walls. FIG. 39A
illustrates a cross-sectional view of a double layered catheter in
accordance with one embodiment of the present specification. The
catheter includes an inner wall 3905 and an outer wall 3915
separated by a thin layer 3910 of air or insulating fluid. The two
walls 3905, 3910 are connected at their proximal and distal ends
(not shown). FIG. 39B illustrates a cross-sectional view of a
double layered catheter in accordance with another embodiment of
the present specification. The catheter includes an inner wall 3925
and an outer wall 3935. The two walls 3925, 3935 are connected at
their proximal and distal ends (not shown) and are connected at
intervals by spokes 3940 which provide additional support. Multiple
air or fluid filled channels 3930 are positioned between the two
walls 3925, 3935. In one embodiment, the inner and outer walls (and
spokes shown in FIG. 39B) are composed of polyether ether ketone
(PEEK).
[0342] One advantage of a vapor delivery system utilizing a heating
coil is that the vapor is generated closer to the point of use.
Traditional vapor delivery systems often generate vapor close to or
at the point in the system where the liquid is stored. The vapor
must then travel through a longer length of tubing, sometimes over
2 meters, before reaching the point of use. As a result of the
distance traveled, the system can sometimes deliver hot liquid as
the vapor cools in the tubing from the ambient temperature.
[0343] The devices and methods of the present specification can be
used to cause controlled focal or circumferential ablation of
targeted tissue to varying depth in a manner in which complete
healing with re-epithelialization can occur. Additionally, the
vapor could be used to treat/ablate benign and malignant tissue
growths resulting in destruction, liquefaction and absorption of
the ablated tissue. The dose and manner of treatment can be
adjusted based on the type of tissue and the depth of ablation
needed. The ablation device can be used not only for the treatment
of Barrett's esophagus and esophageal dysplasia, flat colon polyps,
gastrointestinal bleeding lesions, endometrial ablation, pulmonary
ablation, but also for the treatment of any mucosal, submucosal or
circumferential lesion, such as inflammatory lesions, tumors,
polyps and vascular lesions. The ablation device can also be used
for the treatment of focal or circumferential mucosal or submucosal
lesions of any hollow organ or hollow body passage in the body. The
hollow organ can be one of gastrointestinal tract,
pancreaticobiliary tract, genitourinary tract, respiratory tract or
a vascular structure such as blood vessels. The ablation device can
be placed endoscopically, radiologically, surgically or under
direct visualization. In various embodiments, wireless endoscopes
or single fiber endoscopes can be incorporated as a part of the
device. In another embodiment, magnetic or stereotactic navigation
can be used to navigate the catheter to the desired location.
Radio-opaque or sonolucent material can be incorporated into the
body of the catheter for radiological localization. Ferro- or
ferrimagnetic materials can be incorporated into the catheter to
help with magnetic navigation.
[0344] The above examples are merely illustrative of the many
applications of the system of the present invention. Although only
a few embodiments of the present invention have been described
herein, it should be understood that the present invention might be
embodied in many other specific forms without departing from the
spirit or scope of the invention. Therefore, the present examples
and embodiments are to be considered as illustrative and not
restrictive, and the invention may be modified within the scope of
the appended claims.
* * * * *