U.S. patent application number 12/573944 was filed with the patent office on 2010-05-06 for method and apparatus for the ablation of endometrial tissue.
Invention is credited to Virender K. Sharma.
Application Number | 20100114082 12/573944 |
Document ID | / |
Family ID | 42099552 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100114082 |
Kind Code |
A1 |
Sharma; Virender K. |
May 6, 2010 |
Method and Apparatus for the Ablation of Endometrial Tissue
Abstract
The present invention is directed toward a device that performs
ablation of tissue. The device has a catheter with a shaft through
which an ablative agent can travel, a first positioning element
attached to the catheter shaft at a first position and a second
positioning element attached to the catheter shaft at a second
position. The shaft also has ports through which the ablative agent
can be released.
Inventors: |
Sharma; Virender K.;
(Paradise Valley, AZ) |
Correspondence
Address: |
PATENTMETRIX
14252 CULVER DR. BOX 914
IRVINE
CA
92604
US
|
Family ID: |
42099552 |
Appl. No.: |
12/573944 |
Filed: |
October 6, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61102885 |
Oct 6, 2008 |
|
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|
Current U.S.
Class: |
606/27 |
Current CPC
Class: |
A61B 2560/04 20130101;
A61M 2205/3331 20130101; A61M 25/10 20130101; A61B 2018/00773
20130101; A61B 2017/00084 20130101; A61B 2018/048 20130101; A61B
5/1076 20130101; A61B 2018/00488 20130101; A61B 2018/00029
20130101; A61B 2018/00577 20130101; A61B 2018/00279 20130101; A61B
18/04 20130101; A61M 2205/3368 20130101; A61B 17/24 20130101; A61M
2202/0468 20130101; A61B 18/1492 20130101; A61B 2018/00791
20130101; A61B 2018/00642 20130101; A61M 25/1011 20130101 |
Class at
Publication: |
606/27 |
International
Class: |
A61B 18/04 20060101
A61B018/04; A61B 17/42 20060101 A61B017/42 |
Claims
1. A device to perform ablation of endometrial tissue, comprising
a. a catheter having a shaft through which an ablative agent can
travel; b. 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
c. a shaft comprises a plurality of ports through which said
ablative agent can be released out of said shaft.
2. The device of claim 1 further comprising a second positioning
element attached to said catheter shaft at a second position
3. The device of claim 1 wherein the first positioning element is
conical.
4. The device of claim 1 wherein the first positioning element
comprises an insulated membrane.
5. The device of claim 3 wherein said insulated membrane is
configured to prevent an escape of thermal energy through the
cervix.
6. The device of claim 2 wherein said second positioning element is
disc shaped.
7. The device of claim 6 wherein second positioning element has a
predefined dimension and wherein said dimension is used to
determine a uterine cavity size.
8. The device of claim 6 wherein 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.
9. The device of claim 1 further comprising at least one
temperature sensor wherein said temperature sensor is used to
control delivery of said ablative agent.
10. The device of claim 1 further comprising at least one of
acoustic, electromagnetic, infrared or radiofrequency energy sensor
wherein said sensor is used to measure the dimension of the
uterus.
11. The device of claim 1 wherein said ablative agent is steam.
12. The device of claim 1 wherein said first positioning element is
a covered wire mesh.
13. The device of claim 1 wherein said first positioning element
comprises a circular body with a diameter between 0.01 mm and 10
cm.
14. The device of claim 1 wherein said 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.
15. A device to perform ablation of endometrial tissue, comprising
a. a catheter having a hollow shaft through which steam can be
delivered; b. 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; c. a second positioning element attached to said catheter
shaft at a second position, wherein the second positioning element
is elliptical shaped; d. 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 e.
at least one temperature sensor.
16. The device of claim 15 wherein second positioning element has a
predefined dimension and wherein said dimension is used to
determine a uterine cavity size.
17. The device of claim 15 wherein 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.
18. The device of claim 16 wherein said temperature sensors are
used to control delivery of said ablative agent.
19. The device of claim 15 wherein said first positioning element
comprises wire mesh.
20. The device of claim 15 wherein said 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.
Description
CROSS-REFERENCE
[0001] The present invention relies on U.S. Provisional Application
No. 61/102,885, filed on Oct. 6, 2008, for priority and is hereby
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to medical apparatus and
procedures. More particularly, the present invention relates to a
device for ablation of tissue in a hollow organ comprising a
centering or positioning attachment in order to position the device
at a consistent distance from the tissue to be ablated.
BACKGROUND OF THE INVENTION
[0003] 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.
[0004] Barrett esophagus is a precancerous condition effecting
10-14% of US population with gastro esophageal reflux disease
(GERD) and is the proven precursor lesion of esophageal
adenocarcinoma, the fastest rising cancer in the developed nations.
The incidence of the cancer has risen over 6 fold in the last 2
decades and mortality has risen by 7 fold. The 5-year mortality
from esophageal cancer is 85%. Ablation of Barrett epithelium has
shown to prevent its progression to esophageal cancer.
[0005] Dysfunctional uterine bleeding (DUB), or menorrhagia,
affects 30% of women in reproductive age. These 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 US will undergo hysterectomy by the
age 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. 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) only microwave ablation (MEA) has been approved for use
where the submucosal fibroids are less than 3 cm and are not
occluding the endometrial cavity and, additionally, for large uteri
up to 14 cm.
[0006] The known ablation treatments for Barrett esophagus include
laser treatment (Ertan et al, Am. J. Gastro., 90:2201-2203 [1995]),
ultrasonic ablation (Bremner et al, Gastro. Endo., 43:6 [1996]),
photodynamic therapy (PDT) using photo-sensitizer drugs (Overholt
et al, Semin. Surq. Oncol., 1:372-376 (1995), multipolar
electrocoagulation such as by use of a bicap probe (Sampliner et
al,), Argon Plasma Coagulation (APC;), Radiofrequency ablation
(Sharma et al. Gastrointest Endosc) and cryoablation (Johnston et
al. Gastrointest Endosc). The treatments are delivered with the aid
of an endoscope and devices passed through the channel of endoscope
or alongside the endoscope.
[0007] 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.
[0008] 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 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 tortuous esophagus, proximal esophageal lesions as an
esophagus narrows towards the top, and esophagus at the
gastroesophageal junction due to changes in the esophagus diameter.
Nodular disease in Barrett 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 with 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 esophagus.
[0009] 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. Cryoablation of the esophageal tissues via
direct contact with a liquid nitrogen has been studied in both
animal models and humans (Rodgers et al, Cryobiology, 22:86-92
(1985); Rodgers et al, Ann. Thorac. Surq. 55:52-7 [1983]) and has
been used to treat Barrett esophagus and (Johnston et al.
Gastrointest Endosc) early esophageal cancer (Grana et al, Int.
Surg., 66:295 [1981]). A spray catheter that directly sprays liquid
N.sub.2 or CO.sub.2 (cryoablation) or argon (APC) to ablate Barrett
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 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.
[0010] 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 high risk of bleeding,
perforation and residual disease using traditional endoscopic
resection or ablation techniques.
[0011] Most of the conventional balloon catheters traditionally
used for tissue ablation either heat or cool the balloon itself or
a heating element such as a 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 delivery of energy i.e.
energy sink. In addition reapplication of energy will result in
deeper bur in the area where superficial lining has sloughed.
Further, balloon catheters cannot be employed for treatment in non
cylindrical organs, like 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.
[0012] Accordingly, there is a need in the art for an improved
method and system 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.
SUMMARY OF THE INVENTION
[0013] The present invention 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 a 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.
[0014] 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.
[0015] 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.
[0016] In another embodiment, the present invention 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 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] In another embodiment, the present invention 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.
[0021] 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.
[0022] In another embodiment, the present invention 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.
[0023] 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 an
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.
[0024] In another embodiment, the present invention 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.
[0025] In another embodiment, the present invention 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.
[0026] 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.
[0027] In another embodiment, the present invention 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.
[0028] 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.
[0029] In another embodiment, the present invention 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.
[0030] 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.
[0031] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The present invention is described by way of embodiments
illustrated in the accompanying drawings wherein:
[0033] FIG. 1 illustrates an ablation device, in accordance with an
embodiment of the present invention;
[0034] FIG. 2a illustrates a longitudinal section of an ablation
device with ports distributed thereon;
[0035] FIG. 2b illustrates a cross section of a port on the
ablation device, in accordance with an embodiment of the present
invention;
[0036] FIG. 2c illustrates a cross section of a port on the
ablation device, in accordance with another embodiment of the
present invention;
[0037] FIG. 2d illustrates a catheter of the ablation device, in
accordance with an embodiment of the present invention;
[0038] FIG. 3a illustrates the ablation device placed in an upper
gastrointestinal tract with Barrett esophagus to selectively ablate
the Barrett tissue, in accordance with an embodiment of the present
invention;
[0039] FIG. 3b illustrates the ablation device placed in an upper
gastrointestinal tract with Barrett esophagus to selectively ablate
the Barrett tissue, in accordance with another embodiment of the
present invention;
[0040] FIG. 3c is a flowchart illustrating the basic procedural
steps for using the ablation device, in accordance with an
embodiment of the present invention;
[0041] FIG. 4a illustrates the ablation device placed in a colon to
ablate a flat colon polyp, in accordance with an embodiment of the
present invention;
[0042] FIG. 4b illustrates the ablation device placed in a colon to
ablate a flat colon polyp, in accordance with another embodiment of
the present invention;
[0043] FIG. 5a illustrates the ablation device with a coaxial
catheter design, in accordance with an embodiment of the present
invention;
[0044] FIG. 5b illustrates a partially deployed positioning device,
in accordance with an embodiment of the present invention;
[0045] FIG. 5c illustrates a completely deployed positioning
device, in accordance with an embodiment of the present
invention;
[0046] FIG. 5d illustrates the ablation device with a conical
positioning element, in accordance with an embodiment of the
present invention;
[0047] FIG. 5e illustrates the ablation device with a disc shaped
positioning element, in accordance with an embodiment of the
present invention;
[0048] 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 invention;
[0049] FIG. 7 illustrates endometrial ablation being performed in a
female uterus by using the ablation device, in accordance with an
embodiment of the present invention;
[0050] FIG. 8 illustrates sinus ablation being performed in a nasal
passage by using the ablation device, in accordance with an
embodiment of the present invention;
[0051] 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 invention;
[0052] FIG. 10 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 invention;
[0053] FIG. 11 illustrates fibroid ablation being performed in a
female uterus by using the ablation device, in accordance with an
embodiment of the present invention;
[0054] FIG. 12 illustrates a vapor delivery system using an RF
heater for supplying vapor to the ablation device, in accordance
with an embodiment of the present invention; and
[0055] FIG. 13 illustrates a vapor delivery system using a
resistive heater for supplying vapor to the ablation device, in
accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0056] The present invention provides 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 large area such as Barrett
esophagus. 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 the tissue to be ablated.
[0057] "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.
[0058] "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.
[0059] "Period" refers to the time over which a "dose" of
stimulation is administered to a subject as part of the prescribe
treatment plan.
[0060] The term "and/or" means one or all of the listed elements or
a combination of any two or more of the listed elements.
[0061] The terms "comprises" and variations thereof do not have a
limiting meaning where these terms appear in the description and
claims.
[0062] Unless otherwise specified, "a," "an," "the," "one or more,"
and "at least one" are used interchangeably and mean one or more
than one.
[0063] 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.
[0064] 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 invention. 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. Notwithstanding that the numerical ranges and
parameters setting forth the broad scope of the invention 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.
[0065] 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.
[0066] 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.
[0067] The following disclosure is provided in order to enable a
person having ordinary skill in the art to practice the invention.
Exemplary embodiments are provided only for illustrative purposes
and various modifications will be readily apparent to persons
skilled in the art. 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.
The present invention will now be discussed in context of
embodiments as illustrated by the accompanying drawings.
[0068] FIG. 1 illustrates an ablation device, in accordance with an
embodiment of the present invention. 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. 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. Optional
infrared, electromagnetic, acoustic or radiofrequency energy
emitter and sensor 18 measures the dimensions of the hollow
organ.
[0069] 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 are 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 that, using triangulation, one can calculate the distance of
the catheter from the lesion. Alternatively the infrared,
electromagnetic, acoustic or radiofrequency energy emitter and
sensor 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.
[0070] 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 invention. 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 invention. 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.
[0071] 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 is 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.
[0072] 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 23 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 emitter and
sensor 28 are incorporated to measures the dimensions of the hollow
organ.
[0073] 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
disc 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.
[0074] Optional, one or more, infrared, electromagnetic, acoustic
or radiofrequency energy emitter and sensor 28 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. 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.
[0075] FIG. 3a illustrates the ablation device placed in an upper
gastrointestinal tract with Barrett esophagus to selectively ablate
the Barrett tissue, in accordance with an embodiment of the present
invention. The upper gastrointestinal tract comprises Barrett
esophagus 31, gastric cardia 32, gastroesophageal junction 33 and
displaced squamo-columnar junction 34. The area between
gastroesophageal junction 33 and displaced squamo-columnar junction
34 is Barrett 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 esophagus 31. 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.
[0076] 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 to 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.
[0077] 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 esophagus 31.
FIG. 3b illustrates the ablation device placed in an upper
gastrointestinal tract with Barrett esophagus to selectively ablate
the Barrett tissue, in accordance with another embodiment of the
present invention. 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 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 tissue (for the
proximal attachment).
[0078] FIG. 3b is another embodiment of the Barrett ablation device
where the positioning element 11 is a wire mesh disc. The wire mesh
may have 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
ablated which, in this case, would be the length of the Barrett
esophagus. Optional infrared, electromagnetic, acoustic or
radiofrequency energy emitter and sensor 18 are incorporated to
measures the diameter of the esophagus.
[0079] FIG. 3c is a flowchart illustrating the basic procedural
steps for using the ablation device, in accordance with an
embodiment of the present invention. At step 302, a catheter of the
ablation device is inserted into a hollow organ which is to be
ablated. For example, in order to perform ablation in a Barrett
esophagus of a patient the catheter is inserted into the Barrett
esophagus via the esophagus of the patient.
[0080] At step 304, a positioning element of the ablation device is
deployed. 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. The
diameter of the hollow organ may either 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 (say 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 invention,
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.
[0081] Optional, one or more, infrared, electromagnetic, acoustic
or radiofrequency energy emitter and sensor 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 dimension of the hollow
cavity. The measurement can be performed at one or multiple points
to get an accurate estimate of the dimension 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.
[0082] 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.
[0083] 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
invention 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 micro-processor controlled steam generator.
[0084] 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 the tables below.
TABLE-US-00001 Temp 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 Disorder Max. Temp ENT/Pulmonary Nasal Polyp 60-80
C. Turbinectomy 70-85 C. Bullous Disease 70-85 C. Lung Reduction
70-85 C. Genitourinary Uterine Menorrhagia 80-90 C. Endometriosis
80-90 C. Uterine Fibroids 90-100 C. Benign Prostatic Hypertrophy
90-100 C. Gastroenterology Barrett Esophagus 60-75 C. Esophageal
Dysplasia 60-80 C. Vascular GI Disorders 55-75 C. Flat Polyps 60-80
C.
[0085] 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 prevention patient discomfort and complication. For deeper
tissue ablation, the holding time at the maximum temperature will
be longer, thereby allowing the heat to percolate deeper.
[0086] FIG. 4a illustrates the ablation device placed in a colon to
ablate a flat colon polyp, in accordance with an embodiment of the
present invention. The ablation catheter 10 is passed through a
colonoscope 40. The positioning device 11 is placed proximal 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.
The ablation device allows for focal ablation of diseased polyp
mucosa without damaging the normal colonic mucosa located away from
the catheter ports.
[0087] 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 to the colon polyp. For this application, the
embodiment shown in FIG. 4b would be preferred.
[0088] FIG. 4b illustrates the ablation device placed in a colon to
ablate a flat colon polyp, in accordance with another embodiment of
the present invention. As illustrated in FIG. 4b, the positioning
device is a conical attachment at the tip of the catheter. The
conical attachment has a known length `l ` and diameter `d` that is
used to calculate the amount of thermal energy needed to ablate the
flat colon polyp. 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 `l ` 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. This embodiment can also be used to ablate residual
neoplastic tissue at the edges after endoscopic snare resection of
a large sessile colon polyp.
[0089] FIG. 5a illustrates the ablation device with a coaxial
catheter design, in accordance with an embodiment of the present
invention. 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.
[0090] FIG. 5c shows a completely deployed positioning device 56c.
The infusion ports 57c are out of the sheath 55c. The length `l `
of the catheter 54c that contains the infusion port 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 `l ` 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 and are used to estimate the diameter of a hollow organ or
hollow passage in a patient's body.
[0091] 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 invention. The
vascular lesion is a visible vessel 61 in the base of an ulcer 62.
The ablation catheter 63 is passed though 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 `l ` 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.
[0092] 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 `l ` 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.
[0093] FIG. 7 illustrates endometrial ablation being performed in a
female uterus by using the ablation device, in accordance with an
embodiment of the present invention. 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. 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 through the cervix 71. The second disc shaped
positioning element 79 is deployed close to the fundus of the
uterus 76 positioning the catheter 71 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 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 emitter and sensor can be used to
define cavity size and shape in patients with irregular or deformed
uterine cavity due to conditions such as fibroids.
[0094] In an embodiment, the ablative agent is 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. However, steam, on cooling,
turn 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.
[0095] 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.
[0096] 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 being 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.
[0097] FIG. 8 illustrates sinus ablation being performed in a nasal
passage by using the ablation device, in accordance with an
embodiment of the present invention. A cross-section of the nasal
passage and sinuses comprising nares 81, nasal passages 82, frontal
sinus 83, ethemoid sinus 84, and diseased sinus epithelim 85 is
illustrated. The catheter 86 is inserted into the frontal sinus 83
or the ethemoid sinus 84 through the nares 81 and nasal passages
82.
[0098] 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 ethemoid 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 emitter and sensor can be used to define
cavity size and shape in patients with irregular or deformed nasal
cavity due to conditions such as nasal polyps.
[0099] 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 invention. A
cross-section of the pulmonary system comprising bronchus 91,
normal alveolus 92, bullous lesion 93, and a bronchial neoplasm 94
is illustrated.
[0100] 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.
[0101] 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.
[0102] 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.
[0103] 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.
[0104] FIG. 10 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 invention. A
cross-section of a male genitourinary tract having an enlarged
prostate 101, bladder 102, and urethra 103 is illustrated. The
urethra 103 is compressed by the enlarged prostate 101. The
ablation catheter 105 is passed through the cystoscope 104
positioned in the urethra 103 distal to the obstruction. The
positioning elements 106 are deployed to center the catheter in the
urethra 103 and insulated needles 107 are passed to pierce the
prostate 101. The vapor ablative agent 108 is passed through the
insulated needles 107 thus causing ablation of the diseased
prostatic tissue resulting in shrinkage of the prostate.
[0105] 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.
[0106] FIG. 11 illustrates fibroid ablation being performed in a
female uterus by using the ablation device, in accordance with an
embodiment of the present invention.
[0107] A cross-section of a female genitourinary tract comprising a
uterine fibroid 111, uterus 112, and cervix 113 is illustrated. The
ablation catheter 115 is passed through the hysteroscope 114
positioned in the uterus distal to the fibroid 111. The ablation
catheter 115 has a puncturing tip 120 that helps puncture into the
fibroid 111. The positioning elements 116 are deployed to center
the catheter in the fibroid and insulated needles 117 are passed to
pierce the fibroid tissue 111. The vapor ablative agent 118 is
passed through the needles 117 thus causing ablation of the uterine
fibroid 111 resulting in shrinkage of the fibroid.
[0108] FIG. 12 illustrates a vapor delivery system using an RF
heater for supplying vapor to the ablation device, in accordance
with an embodiment of the present invention. In an embodiment, the
vapor is used as an ablative agent in conjunction with the ablation
device described in the present invention. 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.
[0109] 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 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,
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).
[0110] FIG. 13 illustrates a vapor delivery system using a
resistive heater for supplying vapor to the ablation device, in
accordance with an embodiment of the present invention. In an
embodiment, the generated vapor is used as an ablative agent in
conjunction with the ablation device described in the present
invention. 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 44 delivering additional liquid 44 to the vessel 42.
[0111] 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, 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).
[0112] The device and method of the present invention 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. 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 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 lesion 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.
[0113] While the exemplary embodiments of the present invention are
described and illustrated herein, it will be appreciated that they
are merely illustrative. It will be understood by those skilled in
the art that various changes in form and detail may be made therein
without departing from or offending the spirit and scope of the
invention.
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