U.S. patent application number 11/848565 was filed with the patent office on 2008-09-11 for cutting device positioned via control wire to perform selective discectomy.
This patent application is currently assigned to Laurimed LLC. Invention is credited to Jeff Christian, Brian R. Dubois, Jeffrey Alan Saal, Joel Stuart Saal.
Application Number | 20080221605 11/848565 |
Document ID | / |
Family ID | 39668813 |
Filed Date | 2008-09-11 |
United States Patent
Application |
20080221605 |
Kind Code |
A1 |
Saal; Jeffrey Alan ; et
al. |
September 11, 2008 |
CUTTING DEVICE POSITIONED VIA CONTROL WIRE TO PERFORM SELECTIVE
DISCECTOMY
Abstract
A cutting device for performing a selective discectomy is
disclosed along with a method for using the device whereby the
device is inserted into the intervertebral disc at a point
contralateral, anterior, or anterolateral to a site of herniation.
The device includes a shaft with a cutting mechanism at its distal
end. Control wire(s) attached to either or both shafts may be used
to position cutting components and perform the discectomy.
Inventors: |
Saal; Jeffrey Alan; (Portola
Valley, CA) ; Saal; Joel Stuart; (Portola Valley,
CA) ; Dubois; Brian R.; (Redwood City, CA) ;
Christian; Jeff; (Morgan Hill, CA) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
1900 UNIVERSITY AVENUE, SUITE 200
EAST PALO ALTO
CA
94303
US
|
Assignee: |
Laurimed LLC
|
Family ID: |
39668813 |
Appl. No.: |
11/848565 |
Filed: |
August 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60886860 |
Jan 26, 2007 |
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60887997 |
Feb 2, 2007 |
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60892498 |
Mar 1, 2007 |
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60896226 |
Mar 21, 2007 |
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60945521 |
Jun 21, 2007 |
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60945518 |
Jun 21, 2007 |
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60945519 |
Jun 21, 2007 |
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Current U.S.
Class: |
606/170 ;
606/167 |
Current CPC
Class: |
A61B 90/37 20160201;
A61B 17/320783 20130101; A61B 17/3421 20130101; A61B 2017/003
20130101; A61B 2017/00261 20130101; A61B 2017/00867 20130101; A61B
2017/2905 20130101 |
Class at
Publication: |
606/170 ;
606/167 |
International
Class: |
A61B 17/32 20060101
A61B017/32 |
Claims
1. A cutting device for performing a selective discectomy,
comprising: an outer shaft; and an inner shaft inserted within the
outer shaft and comprising a cutting mechanism at a distal
extremity of the shafts wherein a distal portion of the shafts is
adjustably curvable to assume a plurality of different curved radii
for positioning the cutting mechanism at a herniation site of an
intervertebral disc.
2. The device according to claim 1, further comprising: a first
control wire connected to and extending along a length of the
device; and a second control wire connected to and extending along
a length of the device.
3. The device according to claim 2, wherein the cutting mechanism
comprises a cutting window and a cutting ring which interact to cut
when the inner and outer shafts are moved relative to each other
wherein the first control wire comprises a predetermined curved
distal end portion.
4. The device according to claim 3, wherein the distal portion of
one of the shafts has a predetermined curvature and is comprised of
an elastic or shape memory material and wherein the cutting window
is on the outer shaft and the cutting ring is on the inner
shaft.
5. The device of claim 3, further comprising: a safety tip
positioned at a distal end of one of the shafts, the safety tip
having a diameter greater than an inner diameter of the cutting
mechanism; and a collection chamber comprised of a transparent
material which chamber is positioned in fluid connection with one
of the shafts allowing material to be drawn through one of the
shafts and into the collection chamber and visualized.
6. The device according to claim 1, further comprising: a vacuum
source which reduces pressure within the cutting window; and at
least one of radiopaque marker at predetermined positions along the
device.
7. A device according to claim 1, characterized by a predetermined
curvature extending along a distal portion of one of the shafts to
the distal end of one of the shafts.
8. A method for navigating a cutting device to treat a disc
herniation within an intervertebral disc, comprising: introducing a
cutting device into an intervertebral disc wherein the device
enters the intervertebral disc at a position chosen from
contralateral, anterior, and anterolateral relative to a herniation
site and positioning a cutting window of the device at the
herniation site by moving a control wire which is connected to and
extends along a length of the device; and applying vacuum to the
cutting window in order to draw tissue into the cutting window.
9. The method according to claim 8, further comprising: creating an
opening for the cutting device using a cannula introduced to an
intervertebral disc at a posterolateral extrapedicular point
relative to the herniation site.
10. The method according to claim 8, further comprising:
positioning a cutting window on a distal end of the device at the
site of herniation using a plurality of control wires connected to
and extending along a length of the device; cutting nucleus
pulposus or annulus material from the site of herniation.
11. The method according to claim 10, further comprising:
suctioning material out from the herniation to a collection
chamber; and visualizing material in the chamber.
12. A cutting device for performing a selective discectomy,
comprising: a shaft comprised of a proximal end and a distal end; a
cutting mechanism at the distal end of the shaft; and a
substantially tubular cannula having the shaft inserted therein;
wherein at least a distal portion of the shaft is flexible, has a
predetermined curvature and is comprised of elastic or shape memory
material configured so as to go through and exit from the cannula
and substantially assume the predetermined curvature upon exiting
the cannula the curvature being predetermined in a shape that it
allows the cutting mechanism to be positioned at a herniation site
of an intervertebral disc.
13. The device according to claim 12, further comprising: a first
control wire connected to and extending along a length of the
device.
14. The device according to claim 13, further comprising: a second
control wire connected to and extending along a length of the
device.
15. The device according to claim 14, further comprising: a safety
tip positioned at a distal end of the cutting window, the safety
tip having a diameter greater than an inner diameter of the cutting
mechanism.
16. The device according to claim 12, further comprising: a
collection chamber comprised of a transparent material which
chamber is positioned in fluid connection with the shaft allowing
material to be drawn through the shaft and into the collection
chamber and visualized.
17. The device according to claim 12, further comprising: a vacuum
source which reduces pressure within the cutting window; and at
least one radiopaque marker at predetermined positions along the
device.
18. The device according to claim 13, wherein the first control
wire comprises a predetermined curved distal end portion.
19. A device according to claim 12, wherein the predetermined
curvature is determined prior to insertion into the cannula.
20. The device of claim 19, wherein the curvature is determined by
noting a position of the herniation site using an image.
21. A method for navigating a cutting device within an
intervertebral disc, comprising the steps of: creating an opening
for a cutting device using a cannula introduced to the
intervertebral disc; moving the cutting device through the cannula
and into the intervertebral disc, the cutting device being
comprised of elastic or shape memory material having a
predetermined curvature; allowing the predetermined curvature of
the elastic or shape memory material to position a cutting
mechanism on the device in an area of a diagnosed herniation.
22. The method of claim 21, wherein the opening is created at a
point contralateral or anterolateral to the area of diagnosed
herniation.
23. The method of claim 22, wherein the cutting device is moved
from the created opening to the area of diagnosed herniation in
curved path substantial matching the predetermined curvature of the
cutting device.
24. The method of claim 21, further comprising: positioning a
device at the area of diagnosed herniation which device provides
lavage to irrigate or loosen material for subsequent
evacuation.
25. An intervertebral disc, comprising: a nucleus; a diagnosed site
of herniation positioned at a first side of the intervertebral
disc; a flexible shaft comprising a cutting component at a distal
end of the shaft, the shaft inserted into the intervertebral disc
at a second side contralateral to the first side and positioned
with the cutting component adjacent the diagnosed site of
herniation; and a control wire connected to and extending along a
length of the shaft.
Description
CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional
Application Nos. 60/886,860, filed Jan. 26, 2007; 60/887,997, filed
Feb. 2, 2007; 60/892,498, filed Mar. 1, 2007; 60/896,226, filed
Mar. 21, 2007; 60/945,521, filed Jun. 21, 2007; 60/945,518, filed
Jun. 21, 2007; and 60/945,519, filed Jun. 21, 2007, which
applications are incorporated herein by reference. This application
further incorporates by reference patent applications filed on the
same day herewith and identified as attorney docket numbers
SAAL-006 and SAAL-007.
FIELD OF THE INVENTION
[0002] The present invention is drawn to a flexible surgical
cutting device which is navigable within a subject such as within
the confines of the intervertebral disc and methods of using the
subject devices for performing selective percutaneous
discectomy.
BACKGROUND OF THE INVENTION
[0003] The intervertebral disc is composed of a thick outer ring of
cartilage (annulus) and an inner gel-like substance (nucleus
pulposus). The annulus contains collagen fibers that form
concentric lamellae that surround the nucleus and insert into the
endplates of the adjacent vertebral bodies. The nucleus pulposus
comprises proteoglycans entrapped by a network of collagen and
elastin fibers which has the capacity to bind water. When healthy,
the intervertebral disc keeps the spine flexible and serves as a
shock absorber by allowing the body to accept and dissipate loads
across multiple levels in the spine.
[0004] Over time, the nucleus pulposus becomes less fluid and more
viscous as a result of age, normal wear and tear, and damage caused
from an injury. The proteoglycan and water from within the nucleus
decreases which in turn results in the nucleus drying out and
becoming smaller and compressed. Additionally, the annulus tends to
thicken, desiccate, and become more rigid, lessening its ability to
elastically deform under load and making it susceptible to disc
fissures.
[0005] A fissure occurs when the fibrous components of the annulus
become separated in particular areas, creating a tear within the
annulus. The most common type of fissure is a radial fissure in
which the tear is perpendicular to the direction of the fibers. A
fissure associated with disc herniation generally falls into three
types of categories: 1) contained disc herniation (also known as
contained disc protrusion); 2) extruded disc herniation; and 3)
sequestered disc herniation (also known as a free fragment.)
[0006] In a contained herniation, a portion of the disc protrudes
or bulges from a normal boundary of the disc but does not breach
the outer annulus fibrosis. In an extruded herniation, the annulus
is disrupted and a segment of the nucleus protrudes/extrudes from
the disc. However, in this condition, the nucleus within the disc
remains contiguous with the extruded fragment. With a sequestered
disc herniation, a nucleus fragment separates from the nucleus and
disc.
[0007] As the posterior and posterolateral portions of the annulus
are most susceptible to herniation, in many instances, the nucleus
pulposus progresses into the fissure from the nucleus in a
posteriorly or posterolateral direction. Additionally, biochemicals
contained within the nucleus pulposus may escape through the
annulus causing inflammation and irritating adjacent nerves.
Symptoms of a herniated disc generally include sharp back or neck
pain which radiates into the extremities, numbness, muscle
weakness, and in late stages, paralysis, muscle atrophy and bladder
and bowel incontinence.
[0008] Conservative therapy is the first line of treating a
herniated disc which includes bed rest, medications to reduce
inflammation and pain, physical therapy, patient education on
proper body mechanics and weight control.
[0009] However, if conservative therapy offers no improvement then
surgery is recommended. Open discectomy is the most common surgical
treatment for ruptured or herniated discs. The procedure involves
an incision in the skin over the spine to remove the herniated disc
material so it no longer presses on the nerves and spinal cord.
Before the disc material is removed, some of the bone from the
affected vertebra may be removed using a laminotomy or laminectomy
to allow the surgeon to better see the area.
[0010] However, minimally invasive techniques have been rapidly
replacing open surgery in treating herniated discs. Minimally
invasive surgery utilizes small skin incisions, thereby minimizing
the damaging effects of large muscle retraction and offering rapid
recovery, less post-operative pain and small incisional scars.
Examples of well-known minimally invasive techniques are provided
below.
[0011] Microdiscectomy employs a surgical microscope and
microsurgical techniques to view the disc and nerves. The magnified
view makes it possible for the surgeon to remove only the herniated
disc material which is "pinching" one or more spinal nerve root
through a smaller incision, thus causing less damage to surrounding
tissue.
[0012] Percutaneous discectomy uses a needle-like device which
enters the disc space posterolaterally to remove the herniated disc
material in a piecemeal fashion. Examples of such devices are
described in U.S. Pat. No. 4,678,459. Using suction to pull in disc
material, these cutting devices use a slide-like motion to slice
the tissue which is then aspirated to a collection bottle. However,
as illustrated in FIGS. 1A and 1B, these prior art devices are
typically rigid and therefore, only able to access the center of
the nucleus and remove material along a linear path from the access
point to the center of the nucleus (1). As a result, the tissue
removal is not performed at the site of the injury and thereby has
limited effectiveness. Furthermore, the rigid devices are typically
able to treat only the L4-L5 disc and not the L5-S1 disc that is
commonly the source of patient discomfort. The L5-S1 disc is the
lowest disc on the spine and because it is below the iliac crest,
it is accessible by approaching it from an angle of approximately
30 degrees above the plane of the disc. A rigid device cannot
access the disc unless it can approach the disc from within the
same plane as the disc.
[0013] Endoscopic discectomy inserts an endoscopic probe between
the vertebrae and into the herniated disc space through the skin of
the back using an x-ray video image for guidance. Surgical
attachments (cutters, lasers, and the like) are then sent down the
hollow center of the probe to remove a portion of the offending
disc. However, this direct approach to the disc herniation results
in further injury to the already weakened disc annulus, thereby
increasing the likelihood of subsequent herniations. Sometimes, the
surgical attachments can be used to push the bulging disc back into
place and for the removal of disc fragments and small bone spurs.
The surgeon introduces the endoscope through a relatively large,
(approximately 10 mm or greater), incision into the skin above the
spine, then locates the nerve and disc using direct
visualization.
[0014] Chemonucleolysis involves the injection of chymopapain or
other nucleus dissolving substance into the disc to partially
dissolve the nucleus to alleviate disc herniation. Chymopapain is
an enzyme that works by depolymerizing the proteoglycan and
glycoprotein molecules in the nucleus pulposus. These large
molecules are responsible for water retention and turgidity. When
exposed to chymopapain, the water content within the disc decreases
resulting in shrinkage, thereby causing a reduction in disc height
and girth.
[0015] Nucleoplasty involves the percutaneous removal of disc
material by using a low-temperature resister probe to disintegrate
and evacuate disc material, followed by thermal treatment of
adjacent residual disc material. The procedure combines disc
removal and thermal coagulation to putatively decompress a
contained herniated disc. A posterolateral approach is guided by
fluoroscopy and a discogram may take place at this time to confirm
location. Taking care not to contact the anterior annulus, the
nucleus pulposus is first ablated with radiofrequency waves as the
wand is advanced causing a molecular dissociation process
converting tissue into gas which putatively escapes through the
needle. As the wand is withdrawn, coagulation takes place thermally
treating the channel, which leads to a denaturing of nerve fibers
adjacent to the channel within the nucleus pulposus.
[0016] Intradiscal electrothermal therapy involves the percutaneous
insertion of a specially designed thermal resistance probe followed
by controlled heating of the intervertebral disc. This may result
in limited annulus contraction and coagulation of nerve tissue and
reduction in pain. A needle is inserted posterolaterally into the
disc, generally from the patient's less painful side. A cannula
with a flexible heating tip is threaded circumferentially into the
disc through the nucleus pulposus to the pathologic area of the
annulus.
[0017] Percutaneous Laser Discectomy involves directing a laser to
the target tissue area which absorbs the laser light and converts
it to heat. When the temperature reaches 100.degree. C., tissue
vaporizes and ablation takes places. As a small amount of nucleus
pulposus is vaporized, intradiscal pressure decreases, allowing the
disc to return to its normal state.
[0018] The above methods typically employ a posterior lateral
approach for accessing the nucleus. This approach relies on a rigid
introducer to pierce through the annulus and access the nucleus
pulposus. Generally only the center or anterior portion of the
nucleus is accessible with these methods because of the entry angle
and density of the nucleus. However, most herniations typically
occur in the posterior portion because the posterior wall of the
annulus is thinner than the anterior wall. Therefore, the above
methods are unable to access and treat most herniations at the
specific site of injury.
[0019] Additionally, the above methods are based on the concept in
which the intervertebral disc acts as a closed hydraulic system.
According to this theory, the nucleus pulposus contains a large
amount of water and is surrounded by the inelastic annulus
fibrosis. Therefore, disc pressure decreases by removing nucleus
pulposus material from the center of the nucleus which causes the
herniated disc material to recede toward the center of the disc. As
such, the above methods are designed to merely remove a portion of
the nucleus pulposus within the center of the nucleus but do not
specifically remove material from within the site of injury.
[0020] In light of the foregoing discussion, there is a need for a
device that allows for active and directional navigation within the
confines of the disc to directly access the injured disc material
at the site of herniation. In particular, there is a need for a
device that can navigate within the nucleus pulposus and excise
material directly from the site of herniation within the
fissure.
SUMMARY OF THE INVENTION
[0021] A method of treating a herniation whereby the herniation
site of a patient's intervertebral disc is diagnosed, located and
removed is disclosed. After locating the herniation site on one
side of the disc an opening is creating on the opposite side
(contralateral) or on the same side but anterior to (anterolateral)
the herniation site and a device is navigated through the disc
nucleus to the herniation site. Tissue at the herniation site is
cut away from within the nucleus and removed such as by suction.
The herniation site is never penetrated from the outside thereby
reducing the amount of trauma to the site and improving the chance
of a successful treatment. The device used in the method includes
an elongated shaft, a cutting component, a flexible distal end
portion on the shaft and one or more components used to navigate
the distal end portion to the herniation site.
[0022] An aspect of the invention is a method for navigating a
cutting device to treat a disc herniation within an intervertebral
disc, comprising introducing a cutting device into a nucleus of an
intervertebral disc wherein the device enters the intervertebral
disc nucleus contralateral or anterolateral to a herniation site.
This method may further comprise positioning a cutting window of
the device at the herniation site by moving a control wire which is
connected to and extends along a length of the device and applying
vacuum to the cutting window in order to draw tissue into the
cutting window. The method may be carried out by first creating an
opening for the cutting device using a cannula introduced to the
nucleus of an intervertebral disc at a posterolateral
extrapedicular point relative to the herniation site.
[0023] The method may further comprise positioning a cutting window
on a distal end of the device at the site of herniation using a
plurality of control wires connected to and extending along a
length of the device, and cutting nucleus pulposus material from
within the nucleus at the site of herniation. Still further, the
method may include suctioning material out from the herniation to a
collection chamber; and visualizing material in the chamber.
[0024] Another aspect of the invention includes a method for
navigating a cutting device within an intervertebral disc, said
method, comprising introducing into an intervertebral disc, a
cutting device positioned at a distal end of a flexible shaft;
adjusting a curvature of a distal portion of the shaft while the
cutting device is within the intervertebral disc space; and
positioning a cutting window on the device in an area of a
diagnosed herniation.
[0025] The method may also be carried out wherein the adjusting
curvature is carried out by applying tension or compression to and
relaxing tension or compression on control wires attached to a
distal end of the device whereby applying tension or compression
and relaxing tension or compression on the control wires creates
change in the curvature at a distal end portion of the device.
[0026] Another aspect of the invention is a method for treating a
herniated disc by performing a selective percutaneous discectomy,
by inserting an introducer into said patient; introducing a guide
wire through said introducer; advancing said guide wire to a
herniation site using fluoroscopy; advancing a dilator sheath over
the guide wire; sliding a cannula over the dilator sheath; removing
the dilator; introducing a trocar through the cannula and into the
nucleus; advancing the cannula into the nucleus; removing the
trocar; advancing a cutting device by threading it over the guide
wire, using a cutting device comprising: a shaft assembly
comprising: a cutting device, wherein a distal portion of said
cutting device is curved and wherein said distal portion is
flexible; and debulking said herniation site.
[0027] Yet another aspect of the invention is a method for
navigating a cutting device to treat disc herniations within an
intervertebral disc which is carried out by introducing a cutting
device into a nucleus of an intervertebral disc wherein the cutting
device enters the nucleus contralateral or anterolateral to the
herniation site; and wherein the device is guided within the
confines of the nucleus by adjusting the depth of the cannula
within the nucleus.
[0028] The method may be further carried out by positioning a
cutting window of the device at a site of herniation by applying
tension or compression to and relaxing tension or compression on
control wires attached to a distal end of the device.
[0029] One aspect of the invention is a cutting device for
performing a selective discectomy, comprising an outer shaft and an
inner shaft inserted within the outer shaft and comprising a
cutting mechanism at a distal extremity of the shafts wherein a
distal portion of the shafts is adjustably curvable to assume a
plurality of different curved radii for positioning at a herniation
site of an intervertebral disc characterized by a predetermined
curvature extending along a distal portion of one of the shafts to
the distal end of one of the shafts. The device may further
comprise a first control wire connected to and extending along a
length of the device wherein the first control wire comprises a
predetermined curved distal end portion and a second control wire
connected to and extending along a length of the device. Further,
the distal portion of one of the shafts may have a predetermined
curvature comprised of an elastic or shaped memory material and the
distal portion of the shaft may be shaped in a configuration which
allows the device to be inserted contralateral to the herniation
site and navigated to the site via the shaped configuration.
[0030] Another aspect of the device described above also includes a
safety tip positioned at a distal end of one of the shafts, the
safety tip having a diameter greater than an inner diameter of the
cutting mechanism; and a collection chamber comprised of a
transparent material which chamber is positioned in fluid
connection with one of the shafts allowing material to be drawn
through one of the shafts and into the collection chamber and
visualized.
[0031] Yet another aspect of the device described above includes a
vacuum source which reduces pressure within the cutting window; and
a plurality of radiopaque markers at predetermined positions along
the device.
[0032] Another aspect of the invention comprises a cutting device
for performing a selective discectomy, comprising a cutting
mechanism at a distal end of a shaft and a safety tip positioned at
a distal end of the cutting window, the safety tip having a
diameter greater than an inner diameter of the cutting mechanism
wherein a distal portion of the shaft is adjustably curved by a
control wire extending along a length of the shaft.
[0033] Still another aspect of the invention is a cutting device
for performing a selective discectomy. One embodiment of the device
may include an outer shaft comprising a cutting mechanism at the
end of the shaft or include a substantially tubular cannula with a
cutting window on the outer shaft and a cutting ring on the inner
shaft. The device may be constructed wherein a distal portion of
the outer shaft and inner shaft are flexible, have a predetermined
curvature and are comprised of elastic or shaped memory material
enabling the shaft to go through the cannula and substantially
assume the predetermined curvature upon exiting the cannula the
curvature being predetermined in a shape that it allows the cutting
window to be positioned at a herniation site of an intervertebral
disc. Various cutting components can be used to accomplish a
desired result. The cutting window may be, for example, positioned
on a convex curvature of the device. The device may also include a
first control wire connected to and extending along a length of the
device; a second control wire connected to and extending along a
length of the device; a safety tip positioned at a distal end of
the cutting window, the safety tip having a diameter greater than
an inner diameter of the cutting mechanism and a collection chamber
comprised of a transparent material which chamber is positioned in
fluid connection with the shaft allowing material to be drawn
through the shaft and into the collection chamber and
visualized.
[0034] In another aspect of the invention the device may include a
vacuum source which reduces pressure within the cutting window and
a plurality of radiopaque markers at predetermined positions along
the device.
[0035] The device may include the first control wire with a
predetermined curved distal end portion, wherein the predetermined
curvature is determined prior to insertion into the cannula and
wherein the curvature is determined by noting a position of the
herniation site using an image.
[0036] Another aspect of the invention is a method for navigating a
cutting device within an intervertebral disc, by creating an
opening for a cutting device using a cannula introduced to the
intervertebral disc; moving the cutting device through the cannula
and into the nucleus, the cutting device being comprised of an
elastic material having a predetermined curvature; and allowing the
predetermined curvature of the elastic material to position a
cutting window on the device in an area of a diagnosed
herniation.
[0037] Because the device is, at a given point in time, inserted in
to the disc the invention includes an intervertebral disc,
comprising a nucleus, a diagnosed site of herniation positioned at
a first side of the nucleus, a flexible shaft comprising a cutting
component at a distal end of the shaft, the shaft inserted into the
nucleus at a second side contralateral or anterolateral to the
first side and positioned with the cutting component adjacent the
diagnosed site of herniation, and a control wire connected to and
extending along a length of the shaft.
[0038] The present invention is drawn to methods of maneuvering a
flexible surgical cutting device and methods of use. The cutting
component or components may be configured in different ways and a
cutting window may be configured in an outer or inner shaft. The
device can have different embodiments including a cutting window on
the outer shaft and a cutting ring on an inner shaft so that these
two cutting components can be moved cooperatively relative to each
other and cut tissue. In another embodiment the device is comprised
of an outer shaft which at its distal end is positioned a cutting
tool which is in the form of a circular distal end on the outer
circumference of the shaft which distal end includes a sharp edge.
An inner shaft may be solid and move slidably inside the outer
shaft. The inner shaft comprises a window or opening on a side of a
distal end portion. A safety tip is positioned at a distal end of
the distal end portion of the inner shaft. The device is inserted
into a subject contralateral or anterolateral to the point of disc
herniation and the window or opening is positioned near disc
material (e.g. the herniation) targeted for removal. Those skilled
in the art will recognize that when the herniation is centrally
placed the device may enter either side of the disc and then be
positioned at the herniation where tissue is cut. By applying
vacuum the material is sucked into the anvil window. The outer
shaft is moved in a direction such that the cutter on the distal
end of the outer shaft is advanced over the anvil window. This
movement causes material drawn into the window to be cut by the
cutting tool and the cut material is drawn into the inner shaft and
is evacuated by vacuum towards the proximal end of the outer
shaft.
[0039] In certain aspects, the cutting device is navigatable within
a subject such as within the confines of the intervertebral disc or
nucleus. The navigation may be aided by providing a desired degree
of curvature in a distal portion of the device. The curvature can
be provided by (1) a curved distal end portion on the outer shaft;
(2) a curved distal end portion on the inner shaft; (3) a curved
distal end portion on a wire inserted into a shaft which can be the
inner or outer shaft; or (4) all or any of the ways 1-3 or other
components contemplated by those skilled in the art on reading this
disclosure.
[0040] In other aspects of the invention the device is moved or
navigated through a desired space by the use of control wires which
can be tensioned, loosened, or compressed to curve the distal
portion of the device in one direction or another. The control
wires can be used by themselves or in combination with any or all
of 1-4 above.
[0041] In yet another aspect of the invention there is provided a
kit comprised of a plurality of wires which have a curved distal
end portion wherein each wire is curved in a different amount
relative to other wires. The user can choose one wire and determine
the amount of curvature obtained. Thereafter a different wire with
more or less curvature can be used. The device can be sold as a kit
with a plurality of curved wires and the plurality of curved wires
can be sold together as a separate kit. At least one wire may be
inserted through the lumen of the flexible shaft of the device
which then changes the curvature of the flexible shaft, thereby
repositioning the cutting window in the anvil within the disc.
[0042] In other aspects, the subject devices are used in methods of
performing a selective percutaneous discectomy.
[0043] An aspect of the invention is to provide a flexible surgical
cutting device which is able to navigate through the nucleus
pulposus.
[0044] Another aspect of the invention is to provide a flexible
surgical cutting device which is capable of navigating through the
nucleus pulposus to a target site within the nucleus.
[0045] Another aspect of the invention is to provide a flexible
surgical cutting device which is capable of directly accessing a
site of herniation without damaging the intervertebral disc at the
herniation site.
[0046] Another aspect of the invention is to provide a flexible
surgical cutting device which includes a cutting mechanism to
selectively remove nucleus pulposus material from a specific target
site.
[0047] Another aspect of the invention is to provide a flexible
surgical cutting device which includes a cutting mechanism to
selectively remove nucleus pulposus material from within the
nucleus.
[0048] Another aspect of the invention is to provide a flexible
surgical cutting device which is capable of excising nucleus
pulposus material directly at the site of herniation.
[0049] Another aspect of the invention is to provide a flexible
surgical cutting device which is able to navigate from a
posterolateral extrapedicular entry point through the confines of
the nucleus to a herniation site within a fissure located at the
posterior wall of the annulus.
[0050] Another aspect of the invention is to provide a flexible
surgical device which is configured to curve upon entry into the
nucleus.
[0051] Another aspect of the invention is to provide a flexible
surgical device comprising a curved distal portion wherein the
amount of the curvature is adjustable while it is positioned within
the intervertebral disc.
[0052] Another aspect of the invention is to provide a flexible
cutting device comprising components that have elastic or shaped
memory characteristics.
[0053] Another aspect of the invention is to provide methods of
navigating a cutting device within the intervertebral disc to a
specific target site.
[0054] Another aspect of the invention is to provide methods of
using a control wire to steer a cutting device within the
intervertebral disc to a specific target site.
[0055] Another aspect of the invention is to provide methods of
navigating a cutting device within the intervertebral disc to a
specific target site by adjusting the curve of the shaft.
[0056] Another aspect of the invention is to provide methods of
navigating a cutting device within the nucleus pulposus to a
specific target site by adjusting the depth of a cannula.
[0057] Another aspect of the invention is to provide methods of
treating a herniated disc by navigating a cutting device within the
confines of the nucleus to a specific target site within the
intervertebral space.
[0058] Another aspect of the invention is to provide methods of
treating a herniated disc by navigating a cutting device within the
confines of the nucleus to a herniation site within a fissure.
[0059] Another aspect of the invention is to provide a method for
treating a herniated disc in which the cutting device enters the
nucleus from the side contralateral to the herniation and directly
approaches the herniation site from within the nucleus.
[0060] Another aspect of the invention is to provide a method of
navigating a cutting device within the intervertebral space by
changing the position of the cutting mechanism of the device by
inserting at least one stylus (which may be chosen from a set, each
with different curvatures) into the lumen of the shaft to change
the curvature of the shaft.
[0061] Another aspect of the invention is to provide methods for
treating a herniated disc by performing a selective percutaneous
discectomy, said method comprising the steps of:
[0062] inserting an introducer into said patient;
[0063] introducing a guide wire through said introducer;
[0064] advancing said guide wire to a herniation site using
fluoroscopy;
[0065] advancing a dilator sheath over the guide wire;
[0066] sliding a cannula over the dilator sheath;
[0067] removing the dilator;
[0068] introducing a trocar through the cannula and into the
intervertebral space;
[0069] advancing the cannula into the intervertebral space;
[0070] removing the trocar;
[0071] advancing a cutting device by threading it over the guide
wire, said cutting device comprising:
[0072] a shaft assembly comprising:
[0073] a cutting device,
[0074] wherein a distal portion of said cutting device is curved
and wherein said distal portion is flexible; and
[0075] debulking said herniation site.
[0076] Another aspect of the invention is to provide methods for
navigating a cutting device to treat disc herniations within an
intervertebral disc, comprising:
[0077] introducing a cutting device into an intervertebral disc
wherein the cutting device enters the intervertebral disc
contralateral, anterior, or anterolateral to the herniation site;
and
[0078] wherein the device is guided within the confines of the
intervertebral disc by adjusting the depth of the cannula within
the intervertebral disc.
[0079] Another aspect of the invention is to provide methods for
positioning a cutting window of the device at a site of herniation
by applying tension or compression to and relaxing tension or
compression on control wires attached to a distal end of the
device.
[0080] These and other aspects of the invention will become
apparent to those persons skilled in the art upon reading the
details of the invention as more fully described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0081] The invention is best understood from the following detailed
description when read in conjunction with the accompanying
drawings. It is emphasized that, according to common practice, the
various features of the drawings are not to-scale. On the contrary,
the dimensions of the various features are arbitrarily expanded or
reduced for clarity. Included in the drawings are the following
figures:
[0082] FIG. 1 includes sections 1A and 1B which show an embodiment
of a PRIOR Art discectomy device.
[0083] FIGS. 2A open, 2B closed, 2C open, 2D closed, 2E open, 2F
closed provide a cross-section view of the cutting device in an
open and closed window position in accordance with an embodiment of
the invention.
[0084] FIG. 3 provides a cross-section view of a portion of the
device in accordance with an embodiment of the invention.
[0085] FIGS. 4A, 4B, 5A, 5B, 6A and 6B illustrate the various
target areas within the nucleus in which the subject devices are
able to access.
[0086] FIG. 7 illustrates an embodiment of the cutting device with
a contralateral insertion and now positioned within the confines of
the nucleus at a site of herniation.
[0087] FIG. 8 is a schematic view of the entire device of the
invention in cross-section.
[0088] FIG. 9 is a schematic exploded view of the device of FIG.
10.
DETAILED DESCRIPTION OF THE INVENTION
[0089] Before the present devices and method of treatment are
described, it is to be understood that this invention is not
limited to particular embodiments described, as such may, of
course, vary. It is also to be understood that the terminology used
herein is for the purpose of describing particular embodiments
only, and is not intended to be limiting, since the scope of the
present invention will be limited only by the appended claims.
[0090] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limits of that range is also specifically disclosed. Each
smaller range between any stated value or intervening value in a
stated range and any other stated or intervening value in that
stated range is encompassed within the invention. The upper and
lower limits of these smaller ranges may independently be included
or excluded in the range, and each range where either, neither or
both limits are included in the smaller ranges is also encompassed
within the invention, subject to any specifically excluded limit in
the stated range. Where the stated range includes one or both of
the limits, ranges excluding either or both of those included
limits are also included in the invention.
[0091] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, some potential and preferred methods and materials are
now described. All publications mentioned herein are incorporated
herein by reference to disclose and describe the methods and/or
materials in connection with which the publications are cited. It
is understood that the present disclosure supercedes any disclosure
of an incorporated publication to the extent there is a
contradiction.
[0092] It must be noted that as used herein and in the appended
claims, the singular forms "a", "an", and "the" include plural
referents unless the context clearly dictates otherwise. Thus, for
example, reference to "a lumen" includes a plurality of such lumens
and reference to "the control wire" includes reference to one or
more control wires thereof known to those skilled in the art, and
so forth.
[0093] The publications discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that
the present invention is not entitled to antedate such publication
by virtue of prior invention. Further, the dates of publication
provided may be different from the actual publication dates which
may need to be independently confirmed.
Flexible Navigatable Cutting Device
[0094] The distal portion of the device 10 as shown in FIGS. 2A-2F
can be configured in a number of different embodiments 2A-2F. Those
embodiments shown here should not be considered as a limitation on
the scope of the invention. However, there are features and
characteristics of the invention which may be shared by embodiments
of the invention. One of these features includes the ability to
insert the device contralateral or anterolateral to a point of
herniation as shown within FIG. 7. In accordance with another
feature the distal end portion 10 of the device as shown in FIG. 2
can be bent as shown in FIG. 9. The bending can be accomplished
using a number of different embodiments. For example, the outer
shaft shown in FIGS. 2A-2F can have a preformed curve.
Alternatively, the inner shaft 101 as best shown in FIGS. 2E and 2F
can have a curved configuration at its distal end portion.
Alternatively, a stylus or bent wire 103 as shown in FIG. 2E can be
inserted within the outer shaft 100 or inner shaft 101 to create a
desired degree of curvature. The device may be sold as a kit which
includes a plurality of bent wires or styli 103 wherein each stylus
has a different degree of bend relative to any other stylus in the
kit. When the distal portion o the device 10 is in place in the
patient it can be navigated by including a first stylus to obtain a
desired degree of bending or curvature. The shape of the curvature
in the stylus may represent a three dimensional curve (i.e.
curvature in specific known amounts in each of two different
parallel planes) that allows the operator to approach the disk at
an angle to the plane of the disk and maneuver the device along the
plane of the disk. The stylus can then be moved to the desired
location. If this degree of bending or curvature is no longer
desired the stylus can be removed to allow straightening or can be
removed to insert a different stylus with a different degree of
bending. In this manner it is possible to slowly navigate the
distal end portion of the device 10 to its desired location.
[0095] As shown in FIGS. 2A-2F the window 45 can have a number of
different configurations. The window is preferably positioned along
side of material related to the herniation which material is to be
removed. Once the window is correctly positioned suction is applied
and material is drawn into the window and into a hollow area 104.
While continuing to hold the material within the window and in the
hollow area the distal member 50 also referred to as the safety tip
50 which forms part of the inner shaft is pulled backwards toward
the cutting mechanism 30 which includes a blade 105 which goes
around the entire circumference of the distal end of the outer
shaft 100 as shown in FIG. 2E.
[0096] The diameter of the blade 105 at the end of the cutting
member 30 is slightly smaller than the outer diameter of the safety
tip 50. Accordingly, the safety tip 50 cannot be drawn inside the
outer shaft. Thus, the blade 105 will not cut material unless it is
drawn into the window 45 and moved backwards against the blade 105.
This provides a significant safety advantage when carrying out a
delicate operation.
[0097] Those skilled in the art will understand that there are
other components which can be used to navigate or control the
position of the cutting device 10. For example, within FIG. 3 are
shown control wire 60. By pulling on one control wire and relaxing
the other it is possible to obtain a degree of bending of the
distal end portion of the device. This bending can be relaxed,
readministered or turned in the opposition direction as desired. As
shown in FIG. 2E the distal end member of safety tip 50 prevents
the cutting blade 105 shown in FIG. 2E from cutting unwanted tissue
as the device is positioned in the desired location. Because the
flexible shaft 20 can bend it is possible to position the anvil 40
which includes the window 45 in any desired location.
[0098] As shown in FIG. 3 the hollow opening 70 may run the entire
length of the device. The opening 70 may be used to provide a
vacuum which sucks material into the window 45. Alternatively the
hollow opening 70 may be used to extrude material including water,
saline, or a pharmaceutical formulation comprising an excipient and
a pharmaceutically active drug. The formulation may also be
comprised of an excipient and a desired marker such as any type of
dye as described herein for use in determining the position of the
device relative to bone tissue and a desired target site. The
liquid may be sterile water or saline extruded at a rate sufficient
to loosen disc material prior to evacuation through the window and
evacuation lumen.
[0099] An overall schematic view of the entire device 10 can be
seen in FIG. 8. The elongated outer shaft 100 is shown with the
distal end having the window 45 and safety tip 50 positioned
thereon. The proximal end of the device comprises the control
mechanism as shown in FIG. 8.
[0100] The present invention is drawn to a flexible surgical
cutting device which is navigable within the confines of the
nucleus for selective percutaneous discectomy. The subject devices
include a cutting mechanism to selectively remove nucleus pulposus
material from a specific target site. In certain aspects, the
target site is a specific site within the nucleus. In other
aspects, the target site is the specific site of injury, i.e., the
herniation within the fissure. In some embodiments, the subject
devices directly excise nucleus pulposus material at the site of
herniation. In certain aspects, the subject devices are able to
navigate from a posterolateral extrapedicular (or anterior or
anterolateral) entry point through the confines of the nucleus to a
herniation site located within a fissure at the posterior wall of
the annulus. In a particular embodiment, the subject devices are
able to enter the nucleus from the side contralateral or
anterolateral to the herniation and directly approach the
herniation site from within the nucleus.
[0101] In the embodiment illustrated in FIG. 2E, the cutting device
(10) includes a shaft assembly which comprises an outer flexible
shaft (100) having a cutting mechanism (30) and an inner shaft
comprising an anvil (40). In certain embodiments, the internal
shaft will have a cutting window that comprises a distal window
(45). The outer shaft and the inner shaft are concentric to one
another such that the inner shaft is positioned within the outer
shaft. In some aspects, the cutting device further comprises a
distal member (50) that is larger in diameter then the cutting
mechanism (30). Therefore, when the cutting mechanism is advanced
(60) it cannot be advanced beyond the distal member (50). In
certain embodiments, the distal member includes a beveled distal
tip which aids in the navigation through the thick gelatinous
nucleus pulposus. In other embodiments, the distal member has a
blunt distal tip which will deflect away from neural structures or
blood vessels and not pierce or damage intervertebral structures.
Additionally, the blunt distal tip prevents the subject devices
from penetrating through the fissure or tearing through the
annulus.
[0102] The shaft assembly of the cutting device may be straight,
curved, rigid, flexible, steerable or any combinations thereof as
long as the shaft assembly has adequate column strength to navigate
through the nucleus pulposus without collapsing. In some
embodiments, the shaft assembly has a diameter ranging from about
0.060 inches to about 0.200 inches, where in certain embodiments,
the shaft ranges from about 0.080 inches to about 0.180 inches
while in other embodiments, the shaft ranges from about 0.100
inches to about 0.160 inches. The length of the shaft may range
from about 4.00 inches to about 15.00 inches, where in certain
embodiments, the length ranges from 6.00 inches to about 13.00
inches while in other embodiments, the length ranges from 8.00
inches to about 11.00 inches.
[0103] In certain aspects, the shaft assembly of the present
invention is made from a material that provides elastic or shape
memory characteristics. Examples of materials that have elastic or
shape memory characteristics include, but are not limited to,
Pebax, Nylon, Nitinol, PVC, Stainless Steel wire and Nitinol wire.
By "shape memory characteristics" is meant a material that may be
deformed by the application of a force and fixed into a temporary
shape but is capable of recovering its' original, shape when
subjected to an increase in temperature. In one embodiment, the
shaft may be a braided structure such that the flexibility of the
shaft may be adjusted by varying the configuration of the braiding
pattern or the location of the braid. Further, the flexibility and
mechanical properties of the shaft may be modified by wrapping a
wire around the shaft in a coiled fashion to reinforce or modify
the flexibility of the shaft. The properties and spacing of the
wire may be modified to achieve a variety of parameters.
[0104] Aspects of the invention include curving the distal portion
of the subject cutting device such that upon entry into the
nucleus, the subject device is configured to curve to the site of
herniation from within the confines of the nucleus. As such, the
subject devices will be shaped in a curved fashion but remain
flexible enough to pass through a straight cannula. The radius of
the curve is preformed so the device is navigable through the
confines of the nucleus to a specific target site. In certain
embodiments, the curve is "j shaped" while in other embodiments,
the curve is "c shaped." In certain embodiments, the curvature is a
three dimensional curve to enable access to the disk at an angle to
the plane of the disk. The device may then follow the plane of the
disk as it exits the cannula. In some embodiments, the subject
devices are curved in such a manner that the target site is a
specific site within the nucleus. In other embodiments, the
specific target site is the site of herniation. In these
embodiments, the subject devices are curved to directly advance to
the site of herniation and excise the injured nucleus pulposus and
fragmented annulus material. In certain aspects, upon entry from a
posterolateral extrapedicular entry point, the subject devices are
curved to directly enter a herniation site located within a fissure
at the posterior wall of the annulus. In a particular embodiment,
the subject devices enter the nucleus from the side contralateral
or anterolateral to the herniation and are curved to directly
approach the herniation site through the nucleus.
[0105] In certain embodiments, the distal window (45) may be
bisected by an internal rib (46) as shown in 2E. The outer cutting
mechanism is advanced by sliding the outer shaft over the internal
shaft. When the outer shaft is not advanced, the cutting window is
considered to be "open" as illustrated in the embodiments of FIGS.
2A, 2C and 2E. When the outer shaft is advanced towards the distal
end of the inner shaft, the cutting window is considered to be
"closed" as in FIGS. 2B, 2D and 2F. Aspects of the invention
include navigating the flexible cutting devices with a "closed"
cutting window through the confines of the nucleus to a specific
target site. Once positioned at the specific target site, the outer
shaft is retracted away from the distal end to open the cutting
window directly at the site of injury. In certain aspects, the
cutting window will be positioned directly at the site of
herniation. In a specific embodiment, the cutting window will be
positioned directly at a herniation site within a fissure located
at the posterior wall of the annulus.
[0106] The cutting window may be placed on the outer or the inner
shaft. The cutting window of the subject device may be any suitable
shape such as, but not limited to, rectangular, circular, oval,
square, or triangular. The length of the cutting window may range
from about 3 mm to about 8 mm, where in certain embodiments, the
length ranges from about 4 mm to about 7 mm while in other
embodiments, the length ranges from about 5 mm to about 6 mm. The
cutting window opening may describe an arc with a range of 60
degrees to 300 degrees, where in certain embodiments the arc ranges
from 120 degrees to about 240 degrees and in other embodiments, the
arc ranges from 160 degrees to about 200 degrees.
[0107] In certain aspects, the cutting mechanism is positioned at
the distal end of the outer shaft and is capable of sliding over
the inner shaft to cut material positioned within the distal window
of the cutting window. In some embodiments, the actual
circumference of the distal end of the outer shaft includes the
actual cutting mechanism itself. Aspects of this embodiment include
cutting blades that are "o" shaped and positioned at the tip of the
distal portion of the outer shaft. In certain aspects, the subject
devices may include a cutter in which the sharpened edges are
angled. In some embodiments, the cutting mechanism is configured to
excise tissue by rotating. As such, the outer shaft may be advanced
and rotated to excise the tissue positioned within the open window
of the cutting window. In some embodiments, the cutting mechanism
excises nucleus pulposus at a site directly within the nucleus. In
other embodiments, the cutting mechanism excises nucleus pulposus
directly at the site of herniation within the fissure. In a
specific embodiment, the cutting mechanism excises nucleus pulposus
from within the confines of the nucleus at a herniation site
located within a fissure at the posterior wall of the annulus.
[0108] As discussed above, the anvil includes a cutting window that
is open or closed by advancing and retracting the outer shaft over
the inner shaft. The anvil of the subject devices may be made from
rigid or flexible materials such as but not limited to Pebax,
Nylon, Nitinol, PVC, Stainless Steel wire, Nitinol wire or from a
plastic molded or extruded material. In a specific embodiment, the
anvil includes an extrusion made from a material that has elastic
characteristics which may be attached to a rigid anvil tip, thereby
allowing the anvil to be rigid or flexible. In another embodiment,
the extrusion may form the anvil itself. In certain embodiments,
the cutting device does not include an anvil. In this particular
embodiment, the cutting window is directly located at the distal
portion of the inner shaft.
[0109] In some embodiments, the distal end of the cutting device
may be made of a radiopaque material or include one or more
radiopaque markers at its distal end or throughout spaced
locations. For example, suitable materials may include, but are not
limited to, barium sulfate, bismuth trioxide, iodine, iodide,
titanium oxide, zirconium oxide, metals such as gold, platinum,
silver, tantalum, niobium, stainless steel, and combinations
thereof.
[0110] In certain aspects, the shaft assembly may include a
plurality of lumens. In a specific embodiment, the additional lumen
includes a control wire that is tensioned or compressed to provide
steerage control of the device within the confines of the nucleus.
In some embodiments, the cutting devices include more than one
control wire. In certain aspects, the control wires may be made of
an elastic or shaped memory material to further guide the subject
device to a specific target site. Examples of materials that are
elastic or have shape memory characteristics include, but are not
limited to, Pebax, Nylon, Nitinol, PVC, Stainless Steel wire,
Nitinol wire and plastic. In certain aspects, the control wires may
be flat, round or tapered. As illustrated in the embodiment in FIG.
3 and FIG. 2E, the anvil (40) of the inner shaft may have multiple
lumens where at least one of the lumens has at least one control
wire (60) running through it. In some embodiments, the control
wires are attached to the proximal end of the anvil.
[0111] In certain embodiments, the distal portion of the control
wire may include a spring coil to adjust the flexibility. A forming
ribbon may be incorporated in the distal portion of the control
wire to support the spring coil. The spring coil may be fully
coated with Teflon or other biocompatible materials. The distal
portion of the control wire may be tapered to a smaller diameter
toward the distal end. The control wire is also preferably
radiopaque so as to be visible under fluoroscopy.
[0112] The actual dimensions of the control wire will vary with the
stiffness and tensile strength of the material used to form the
control wire. The control wire may also have various other shapes
other than tapered or a flattened ribbon such as triangular, oval,
wedge or rectangular in cross-sectional shape. In some embodiments,
the control wire preferably has a total length greater than or at
least equal to the length of the shaft assembly.
[0113] In certain embodiments, a deflectable stylus consisting of
elastic or shaped memory material that is encapsulated by a
straight, rigid sheath may be inserted into the shaft of the device
through the proximal end of the device. Once the stylus (wire with
a distal end portion with a known curvature) and sheath are in
place, the sheath is retracted to allow the stylus to return to
its' curved shape. The stylus may have a radius of curvature that
is greater than or less than the preformed curvature of the shaft.
Therefore, the presence of the stylus within the shaft of the
device causes the radius of curvature of the shaft to increase or
decrease depending on the corresponding curvature of the stylus.
The sheath is typically but not necessarily withdrawn from the
stylus while the shaft is still constrained by the cannula. The
shaft is then advanced distally out of the cannula and into
position at the site of herniation. The stylus is then withdrawn
from the distal end of the shaft and into the sheath wherein both
components are withdrawn from the shaft of the device to enable the
debulking process to commence.
[0114] In certain embodiments, a deflectable stylus consisting of
elastic or shaped memory material may be inserted into the shaft of
the device to establish a radius of curvature of the shaft. Several
styli with a variety of curvatures may be supplied to allow the
operator to choose the radius of curvature desired for a particular
treatment modality allowing the window to be placed along side of
material to be removed such as along side of the herniation. The
stylus may be inserted into the shaft and the shaft may then be
advanced to the cutting site and the debulking process may commence
with the stylus still in position within or adjacent to the
shaft.
[0115] In certain embodiments, several styli may be used to enable
the operator to maneuver the shaft of the device to a position
within the disc that requires the shaft of the device to follow a
complex, three dimensional curvature, such as is typically required
to access the L5-S1 intervertebral disc. In this embodiment, each
stylus has a slightly different curvature that when used in
progression, enables the shaft to be advanced to a position that
cannot be obtained by a single stylus described which has a single
curvature.
[0116] The subject devices generally include a handpiece which is
ergonomically molded and contoured to fit comfortably within the
palm of a hand. In certain aspects, the handpiece is composed of a
durable and rigid material, such as medical grade polymer of
desired structural integrity. In some embodiments, the handpiece
includes a molded polymeric housing which encloses a small motor
and a power supply. In certain embodiments, the handpiece may
include a rotatable wheel member which is directly connected to the
control wires. By rotating the knob member, the user is able to
adjust the control wires to navigate through the nucleus pulposus
to a specific target site. In some embodiments, the rotating wheel
member is able to adjust the curve of the control wire, which in
turn, controls the radius of curvature of the subject cutting
device shafts. In these embodiments, the control wires are attached
to the wheel member so that when rotated in a first direction,
tension is applied to the control wire, thereby causing the radius
of shaft curvature to decrease. By rotating the wheel member in a
second direction, the tension is reduced, thereby causing the shaft
radius of curvature to increase at its distal end. By adjusting the
rotating wheel, the curvature of the shaft may be adjusted in
micrometer intervals, which in turn adjusts the curvature of the
subject cutting devices. In other embodiments, the rotatable wheel
may be replaced with a lever or sliding shuttle mechanism attached
to the control wire(s) to accomplish the desired effect.
[0117] As illustrated in FIG. 3, the anvil (30) of the inner shaft
has multiple lumens for control wires (60) but may have additional
lumens for treatment modalities. As such, the subject devices allow
additional treatment methods to be performed directly at the site
of herniation. For example, additional treatments include but are
not limited to aspirating material, providing make up air that
allows a pressure differential on the excised tissue and causes it
to evacuate from the operative site, delivering medicaments,
delivering injection dye or providing a liquid jet. Additionally,
the lumens within the shaft may be used to allow passage of a
visualization device such as a fiber optic camera. Alternatively,
the fiber optic system may be integrated into the design of the
shaft.
[0118] In certain embodiments, the additional lumen may be employed
to provide a vacuum source. In this embodiment, the vacuum source
is used to evacuate the tissue excised within the cutting window.
In some aspects, the cutting device includes a lavage channel. As
such, the instant invention is configured to create an aspiration
force for withdrawing material excised by the subject cutting
devices.
[0119] In some embodiments, the cutting device is connectable to an
external aspiration source, such as a vacuum. While in another
embodiment, the aspiration source is self-contained within the
device, thereby not requiring an external aspiration source. For
example, the subject devices may include a CO.sub.2 cartridge or a
vacuum reservoir. The vacuum source provides the suction force for
withdrawing material during the cutting process or after the
nuclear material has been cut by the subject devices. For example,
in some embodiments a CO.sup.2 cartridge is used to create a vacuum
via a venturi or by actuating a piston that creates suction within
the shaft of the cutting device.
[0120] In some aspects, the vacuum source may also provide a
suction which positions the tissue within the cutting window prior
to excising the tissue. In certain aspects, the excised material is
drawn from the nucleus into the window of the inner shaft of the
subject devices, cut by the cutting element, and then drawn outside
of the patient's body. In a specific embodiment, the vacuum source
is connected to or included within the housing of the handpiece. In
certain aspects, the handpiece of the cutting device may
additionally include a valve positioned to disconnect the shaft of
the device from the vacuum source and allow additional devices such
as catheters and styli to be advanced through the lumen of the
subject cutting devices. The valve directs the opening to the inner
shaft to the vacuum source or to an opening in the proximal end of
the instrument.
[0121] The subject devices may further include a tissue collection
chamber which is structured to collect and contain the nuclear
material excised by the subject cutting devices. In certain
embodiments, the collection chamber is made of a transparent
material, thereby allowing direct visualization of the excised
tissue. In other aspects, the collection chamber may facilitate the
quantification and/or other analysis of the material removed from
the intervertebral disc. In a particular embodiment, the collection
chamber is directly connected to or part of the housing of the
handpiece of the subject cutting devices. In another embodiment,
the collection chamber may be located along the vacuum tubing
between the handle and the vacuum source and the chamber may be
sufficiently transparent that is content can be viewed
visually.
[0122] In another embodiment, the anvil may include an additional
lumen for injecting radiopaque dye into the operative site for
visualization purposes. For example, dilute barium sulphate
solution may be injected through the lumen into the nucleus and the
patient scanned using radiographic techniques. Additional suitable
materials that provide radio-opacity are well known in the art such
as bismuth trioxide, iodine, iodide, titanium oxide, zirconium
oxide, metals such as gold, platinum, silver, tantalum, niobium,
stainless steel, and combinations thereof.
[0123] In certain embodiments, the additional lumen is employed to
deliver a medicament within the disc. For example, the lumen may
deliver a pharmaceutical agent, chemonucleolytic enzymes, hydrogel
substances, osteoinductive substances, chondrocyte-inductive
substances, sealants, collagen, fibrinogen, thrombin and
combinations thereof.
[0124] In some embodiments, the additional lumen is a pressure
lumen which delivers a liquid jet for cutting and removing nucleus
pulposus material. The pressure lumen is configured to have
sufficient burst strength to enable it to conduct a high pressure
liquid through a nozzle, thereby forming a liquid jet. The burst
strength should be selected to meet and preferably exceed the
highest contemplated pressure of the liquid supplied for use in the
discectomy. The liquid utilized for forming the liquid jet may be
any fluid that can be maintained in a liquid state at the pressures
and temperatures contemplated for performing the discectomy. The
liquid should be physiologically compatible, for example, typical
liquids include but are not limited to saline solution or sterile
water. In certain aspects, the pressure fluid is adjustable between
low pressure and high pressure. In some embodiments, the subject
devices include a deflector which prevents the liquid jet from
being misdirected during use. Aspects of this embodiment include
delivering a high pressure fluid through the lumen to cut, remove
or to loosen adherent fragments of nucleus pulposus material to
facilitate excising and removal of material by suction.
[0125] In certain embodiments, the surgical devices are disposable.
By "disposable" is meant that the device may be "disposed of" or
"thrown away" after use in a single patient. The device may be
sterilized, placed in a sterile container, removed from the
container immediately prior to use, used and thereafter
discarded.
[0126] It will be apparent to those of skill in the art that the
subject cutting devices may be delivered to the intervertebral disc
using techniques and apparatuses readily well known in the art.
Typically, the subject devices are advanced through the lumen of an
introducer. The introducer, in its simplest form, can be comprised
of a hollow needle-like device (optionally fitted with an internal
removable obturator or trocar to prevent clogging during initial
insertion) or a combination of a simple exterior cannula that fits
around a trocar. The result is essentially the same: placement of a
hollow tube (the needle or exterior cannula after removal of the
obturator or trocar, respectively) through skin and tissue to
provide access into the annulus fibrosis. The hollow introducer
acts as a guide for introducing instrumentation. More complex
variations exist in percutaneous instruments designed for other
parts of the body and can be applied to design of instruments
intended for disc operations. Examples of such obturators are well
known in the art. A particularly preferred introducer is a 17- or
18-gauge, thin-wall needle with a matched obturator, which after
insertion is replaced with a probe of the present invention
[0127] In certain aspects, guide wires are employed as a
placeholder to access the intervertebral disc. The guide wire may
be manufactured from a high strength alloy containing cobalt,
nickel, chromium or to a composite product having a portion formed
of an alloy and a superelastic alloy such as Nitinol.
[0128] In some embodiments, a cannula is employed to introduce the
cutting devices of the present invention into the intervertebral
disc. The cannula generally comprises a tubular structure which
serves as a conduit extending between the exterior of the body and
the intervertebral disc. Essentially, the subject cutting devices
advance through the cannula to the intervertebral disc. The
interior of the cannula may also be coated to improve the ability
of the shaft to transfer tissue through the shaft. Such coatings
include but are not limited to parylene, silicone, polyimide and
the like. The inner lining and coating also provides for smooth
gliding over the guide wire to prevent kinking or snagging of the
cannula. In some embodiments, the subject devices advance through
the distal tip of the cannula. In other embodiments, the cannula
includes an orifice. Aspects of this embodiment include advancing
the subject devices through the cannula and out via the orifice. By
adjusting the position of the orifice, the entry point of the
subject devices within the nucleus may additionally be
controlled.
[0129] In certain embodiments, the subject devices may further
include a dilator sheath which is configured to slide or pass over
the guide wire for introducing the cannula onto the guide wire. The
sheath may be made of a variety of materials including but not
limited to polyester, rayon, polyimide, polyurethane, polyethylene,
polyamide and silicone. The dilator sheath supports the cannula and
guide wire when the cannula is advanced through the body
percutaneously and also protects the cannula from any collateral
damage that may be associated with inserting the cannula over the
guide wire. The dilator sheath also provides a conduit for the
cannula into the nucleus when the cannula encounters resistance
which could damage the treatment modalities associated with the
cannula and the subject devices.
Methods of Navigating a Cutting Device within the Nucleus
Pulposus
[0130] Once the flexible cutting devices are introduced into the
nucleus, the subject devices are able to navigate and maneuver
through the gelatinous material of the nucleus pulposus. Aspects of
the invention include curving the distal portion of the subject
devices such that upon entry into the nucleus, the subject device
is configured to curve away from the distal end of the cannula at
an angle ranging from 15 degrees to 90 degrees. In some
embodiments, the angle ranges from 30 degrees to 75 degrees while
in other embodiments, the angle ranges from 45 degrees to 60
degrees. In certain embodiments, the cutting device is configured
to curve away from the distal end of the cannula towards the
posterior wall of the annulus. In certain aspects, the preformed
curve enables the flexible cutting devices to directly access the
nucleus pulposus within the disc plane regardless of which disc is
specifically injured. The anatomical location of certain discs
requires that the cannula must approach and enter the disc at an
angle to the disc rather than in the same plane as the disc.
Therefore, a particular embodiment is configured to compensate for
this angle by advancing beyond the distal end of the cannula in a
curved plane that is at an angle to the cannula.
[0131] The subject cutting devices may be steered in a particular
direction by adjusting the depth of the cannula within the nucleus.
By advancing the cannula into the nucleus, the subject devices are
navigated to an area which is further away from the cannula site of
entry. In certain embodiments, the subject devices employ rails
that allow the cannula depth to be adjusted by sliding the cannula
backwards and forwards. By drawing back the cannula, the radius of
curvature of the shaft may be increased and the subject devices are
able to access an area of the nucleus which is further away from
the cannula site of entry. Conversely, if the cannula is inserted
more deeply into the disk after the distal end of the device is
already in the nucleus, the radius of curvature of the device may
be decreased and the subject devices are able to access an area of
the nucleus which is closer to the cannula site of entry. As such,
the subject cutting devices may be steered through the nucleus
pulposus and navigated to a specific target site by adjusting the
depth of the cannula within the nucleus pulposus and preforming the
device to a specific curve.
[0132] The subject cutting devices may be steered by advancing the
shaft of the cutting device from the distal tip of the cannula and
subsequently adjusting the depth of the cannula within the disc. By
increasing the depth of the cannula, the radius of curvature of the
shaft is decreased and by decreasing the depth of the cannula, the
radius of curvature of the shaft is increased. As a result, the
operator may redirect the shaft of the device while advancing
it.
[0133] One aspect of the invention provides a method of treating a
herniated disc by performing a selective percutaneous discectomy.
The patient is first diagnosed as having a herniated disc. The
patient is then subjected to imaging such as MRI imaging in order
to determine the location of the herniation. At this point markers
which can be viewed on X-ray or other imaging devices may be placed
on the surface of and/or within the patient to provide for
assistance in navigation. In a manner as described above an
introducer is placed into the patient at a point contralateral to
the location of the herniation as is shown in FIG. 4A. One or more
guidewires are slid through the introducer into the intravertrabal
disc. A dilator sheath is advanced over the guidewire and a cannula
is slid over the dilator sheath. The disc annulus generally pierced
by a mechanism referred to as a trocar. The cutting device of the
invention is advanced through the cannula into the nucleus of the
intravertebral disc as shown in FIGS. 4A and 4B. In FIG. 4B the
portion 200 which is shaded is the posterior portion of the
nucleus.
[0134] The device 10 of the invention as shown in FIG. 4B is
navigated to the point of herniation 106. At this point a vacuum
may be applied and material of the herniation 106 may be drawn into
the window 45 as shown in FIGS. 2E and 2F. Once the material is
drawn into the window the window portion is moved in a direction
towards the blade 105 shown in FIG. 2E and cut away. Thereafter the
cutaway material can be sucked through a hollow portion of the
device and removed from the patient.
[0135] As shown in FIGS. 5A and 5B the flexible shaft 20 is
generally inserted contralateral to the herniation 106. The distal
portion 107 is curved at an angle which is nearly 90.degree.
relative to the shaft 20. At this point a stylus or curved wire 103
is shown in FIG. 2A could be inserted to curve the distal portion
107 further and along with forward movement could place the distal
end 50 in close proximity to the target site of herniation 106. The
device can be rotated or turned and different types of stylus with
different degrees of bend can be used to navigate the window 45 so
that it is positioned adjacent to the herniation 106.
[0136] As shown in FIGS. 6A and 6B the distal end 50 of the device
is inserted well within the point of herniation 106. The window
portion 45 can be seen in FIG. 7. It is at this point that material
is drawn into the window 45 and the distal end 50 is retracted into
the outer shaft so that the blade 105 cuts the material away so
that it can be drawn into the device and out of the patient. One of
the features of the invention is that the safety tip 50 is larger
in diameter as compared to the circumference of the blade 105.
Accordingly, when the safety tip 50 is pulled back against the
blade 105 the material inside the window 45 is cut off and the
blade is blocked from cutting material which should not be cut.
[0137] In some embodiments, the cutting devices employ one or more
control wires to steer the anvil to the specific site of herniation
from within the confines of the nucleus. In certain embodiments,
the cutting device may have one control wire on the outside radius
and one on the inside of the radius of the curve around which the
anvil or window opening on the inner shaft is to be guided. By
compressing the outside control wire and tensioning the inside
control wire, the anvil can be directed in a smaller radius than
the radius described by the elastic or shaped memory alone.
Conversely, by compressing the inside control wire and tensioning
the outside control wire, the anvil may be directed in a larger
radius than that described by the elastic or shaped memory alone.
Alternatively, a single control wire may be used on either the
inside or outside radius that may be compressed or tensioned to
cause the radius of curvature to change.
[0138] The cutting device may be navigated and steered through the
confines of the nucleus to a specific target site by adjusting at
least one or a combination of the specific depth of the cannula,
the preformed curved of the device or the control wires. As
illustrated in FIGS. 4A and 4B, in certain embodiments, the subject
cutting devices may be navigated and steered towards the posterior
wall of the annulus. The hatched section (200) of the nucleus
depicted in FIG. 4B illustrates the posterior portion of the
nucleus. The flexible cutting devices of the present invention are
able to access and excise material from target sites within this
posterior portion by adjusting at least one or a combination of the
specific depth of the cannula, the preformed curved of the device
or the control wires.
[0139] The target site is a specific site within the nucleus itself
as illustrated in FIGS. 5A and 5B. In other aspects, the target
site is the specific site of injury, i.e., the herniation site as
illustrated in FIGS. 5A and 5B. In certain embodiments, the subject
devices navigate from a posterolateral extrapedicular entry point
to a herniation site within a fissure located at the posterior wall
of the annulus. In a particular embodiment, the subject devices are
able to enter the nucleus from the side contralateral to the
herniation and directly approach the herniation site from within
the nucleus. Therefore, by adjusting at least one or a combination
of the specific depth of the cannula, the preformed curved of the
device and the control wires, the subject devices are able to
excise nucleus pulposus material at a specific target site, such as
within the nucleus itself or at a specific herniation site.
[0140] The subject devices may not require elastic or shaped memory
or steerable characteristics of the cutting device shaft to
position the subject devices within the nucleus. Aspects of this
embodiment employ at least one guide wire which guides the subject
devices to a position within the confines of the nucleus. The
guidewire may navigate within an intradiscal section of the
intervertebral disc adjacent and/or through an inner wall of an
annulus of the disc to a specific site within the nucleus. In other
embodiments, at least one guide wire is employed to guide the
cannula for accessing the confines of the nucleus. The shaft is
capable of being advanced relative to the guide wire such that the
shaft follows a path of the guide wire within the intradiscal
section of the disc to the selected site within the nucleus.
[0141] In a specific embodiment, the subject devices do not include
any material having elastic or shape memory characteristics. As
such, the control wires in this particular embodiment are
compressed or tensioned or combinations thereof to change the
direction of the anvil within the confines of the nucleus to access
a specific target site. In certain aspects, by compressing or
tensioning the control wires or combinations thereof, the cutting
devices are able to access and excise material at a target site
within the nucleus or a target site specifically at the site of
herniation.
[0142] The device as shown in an exploded schematic view in FIG. 9
is described below. Those skilled in the art will understand that
other embodiments of the invention can be constructed utilizing
similar components. Handle embodiments may be changed as features
are added and removed from the described embodiment. For example,
in its' simplest embodiment, the handle may be designed to actuate
the cutting mechanism with no provision for actuating control wires
or inserting a stylus.
[0143] The Anvil component 40 has vacuum within lumen 70 that pulls
tissue into a window 45 to be excised when the cutter 30
advances.
[0144] The Safety Tip 50 provides a blunt tip on the end of the
Anvil 40 and reduces the likelihood of accidentally penetrating the
disk annulus. Additionally, the diameter of the Safety Tip 50 may
be larger than the diameter of the Cutter 30 and Anvil 40, thus
preventing the cutter 30 from advancing past the Safety Tip 50.
[0145] The Control knob 71 used to provide tension or compression
on the control wire 60 by rotating the knob 71 clockwise or
counter-clockwise. The Control Wire 60 (as shown in FIG. 3) is
connected to the Control Knob 71 by inserting it into a slot in the
shaft.
[0146] The Shaft 46 is comprised of the Cutter Shaft 100 on the
outside and the Inner Shaft 101 on the inside (see FIG. 2E). The
Inner Shaft 101 has vacuum within a lumen that is used to evacuate
excised tissue. The Inner Shaft 101 also has a lumen containing a
Control Wire 60 that may also transmit makeup air or saline in the
space between the Control Wire 60 and the wall of the lumen (see
FIG. 3). The Cutter 30 is attached to the distal extremity of the
Outer Shaft 100 and serves to excise tissue that is drawn into the
Anvil window 45 when the Outer Shaft 100 is advanced linearly
relative to the Inner Shaft 101 (see FIG. 2F).
[0147] The function of the Cutter Grasp 108 (see FIG. 9) is to
connect the Trigger Shaft 109 to the Outer Shaft 100. The Cutter
Grasp 108 has a lumen that encapsulates the Outer Shaft 100 and is
bonded to the Outer Shaft 100. The Cutter Grasp 108 has a "key" 120
that is inserted into a slot on the Trigger Shaft 109.
[0148] Trigger Shaft 109 transmits linear motion from the Trigger
110 to the Outer Shaft 100 via the Cutter Grasp 108. The Trigger
Shaft 109 moves proximally-distally, and is constrained by a
channel within the handle halves 72 and 73.
[0149] The handle is made of two components, the Handle Left (72)
and the Handle Right (73). The function of the Handle Halves is to
provide an ergonomically pleasing interface to the operator and
house the mechanisms in the handle. The Handle Left 72 and Handle
Right 73 components may be made of plastic and either injection
molded or machined using clear or opaque materials. The Handle Left
72 and Handle Right 73 may be assembled to one another using
mechanical fasteners such as screws, ultrasonic welding, by bonding
with solvents or adhesives, or by press fitting together male and
female features.
[0150] The Adapter Tube 111 connects the Sight Tube 112 to the Luer
fitting 113.
[0151] The Luer fitting 113 connects the Adapter Tube 111 to the
Stop Cock 114.
[0152] Sight tube 112 is used as a collection chamber to enable
visualization of excised tissue. This visualization allows the user
to determine if tissue is being removed and how much tissue has
been removed and is different from indirect or direct visualization
used to see the area where tissue may be removed. The Sight Tube
112 is connected to the proximal end of the Inner Shaft 101 on its'
distal end and to the Adapter Tube 111 on its' proximal end. The
lumen in the Sight Tube 112 is a larger diameter than the Inner
Shaft 101, therefore, when the tissue reaches the Sight Tube 112,
it slows and adheres to the side of the Sight Tube 112 rather than
passing through to the Adapter Tubelll. Alternatively, a filter
component (not shown) may be added to prevent tissue from passing
through the Sight Tube 112.
[0153] The Stop Cock 114 has two positions; in one position it
opens the passage between the Sight Tube 112 and the Vacuum Tube
(not shown) that connects to the Stop Cock 114 and exits the butt
115 of the Handle Grip 73. When placed in this position, the vacuum
is open to the Anvil 40, Inner Shaft 101, and Sight Tube 112
system. When the Stop Cock 114 is in its' second position, the
vacuum is shut off to the Anvil 40, Inner Shaft 101, and Sight Tube
112 and the rear luer is open to the Sight tube 112 and Inner Shaft
101 to enable the insertion of a Stylus, endoscope, and dye
injection catheters, through the Inner Shaft 101 and Anvil 40.
[0154] The Vacuum Tube Luer Fitting 116 connects a conventional
Vacuum Tube, (not shown) to the Stop Cock 114 within the grip of
the handle. The Vacuum Tube (not shown) extends out of the butt of
the handle 115 and connects the device to a vacuum source.
[0155] The Trigger Return Spring 117 is connected to a pin 118 in
the Handle on its' proximal end and to a pin 119 inserted in the
Trigger Shaft 109 on its' distal end. The tensile force is
increased on the Trigger Return Spring 117 when the Trigger 110 is
actuated, when the Trigger 110 is released, the Trigger Return
Spring 117 pulls the Trigger 110 back into position.
[0156] The Trigger 110 is actuated by the operator to actuate the
Outer Shaft 100 and is connected to the Outer Shaft 100 via the
Trigger Shaft 109 and Cutter Grasp 108 mechanism. A pin 119
inserted into the Trigger Shaft 109 slides within a slot on the
Trigger 110.
Methods of Treating a Herniated Disc
[0157] Embodiments of the present invention further include methods
of treating a herniated disc. The methods employ the cutting
devices of the present invention to selectively remove nucleus
pulposus material from a specific target site. In certain aspects,
the target site is a specific site within the nucleus. In other
aspects, the specific target site is the site of herniation in
which the subject devices directly access and excise nucleus
pulposus material at the site of herniation within the fissure. In
a particular embodiment, the subject devices are able to enter the
nucleus from the side contralateral or anterolateral to the
herniation and directly approach the herniation site from within
the nucleus. Therefore, the subject devices are able to perform a
selective percutaneous discectomy by navigating through the
confines of the nucleus to a specific target site.
EXEMPLARY METHODS
[0158] It will be apparent to one of skill in the art that the
cutting devices of the present invention may be employed in a
variety of different protocols for performing a discectomy. As
such, the method provided below is exemplary and not to be
construed as a limitation.
Example 1
Indirect Visualization
[0159] In general, a patient is examined and diagnosed with a
herniated disc. Imaging technology such as MRI or an X-ray device
is used to locate the position of the herniated disc. An introducer
such as a hypodermic needle is provided that is inserted in a
patient's body so that its distal end creates a small annular
opening leading to the nucleus pulposus. A guide wire is slid into
position within and through the introducer lumen so that a distal
tip of the guide wire is positioned at the selected location within
the nucleus by advancing or retracing the guide wire in the
introducer lumen and optionally twisting the proximal end of the
guide wire to precisely navigate the guide wire. A plurality of
Guide Wires with different curvatures may be provided that enable
the operator to navigate to precise locations within the nucleus
pulposus.
[0160] A small incision is then made in the patient's skin and
subcutaneous tissue which facilitates access of a dilator sheath.
The introducer is then removed while leaving the Guide Wire in
place and the dilator sheath is advanced over the guide wire to
dilate the opening from the patient's skin to the intervertebral
disc. The dilator sheath abuts the disc but does not penetrate the
disc.
[0161] Next, a cannula having at least one lumen is slid over the
sheath and navigated to the distal most portion of the guide wire
within the nucleus and the guide wire and cannula are then removed
from the patient and lumen of the cannula. Alternatively, the
cannula may be advanced to abut the disc annulus, the guide wire
and dilator are removed from the patient and cannula lumen, and a
trocar is advanced through the lumen of the cannula to pierce the
disc annulus and gain entry to the nucleus.
[0162] A cutting device of the present invention is advanced
through the lumen of the cannula. As the cutting device advances,
it follows a curved path to the site of disc herniation because the
distal portion of the subject device is configured to curve away
from the distal end of the cannula towards the posterior wall of
the annulus. The distal tip of the cutting device is configured
with a Safety Tip 50 to minimize the possibility of piercing the
wall of the annulus from the inside.
[0163] The subject cutting device will be advanced until the open
window of the cutting window (45) is directly positioned at the
target site as illustrated in FIG. 7. Markers which can be seen on
X-ray may be present at specific locations along the device and at
cutting window 45. At different points in time an X-ray image may
be taken and used to adjust the position of the window at the
herniation. In certain aspects, the target site is a specific site
within the nucleus. In other aspects, the specific target site is
the specific site within the fissure of herniation. A vacuum may be
applied to draw tissue into the open window 45 in the anvil 40 and
the outer shaft 100. The Cutter 30 of the subject device will be
advanced towards the distal end of the Anvil 40 thereby cutting any
nucleus pulposus material present in the open window (45). In some
embodiments, the Inner shaft 101 includes a lumen which
communicates with a vacuum source that may be applied through the
lumen to draw tissue into the cutting window of the anvil. The
subject cutting device excises tissue until the disc herniation has
been adequately debulked. The subject device is then withdrawn from
the cannula and the entry site is closed with a suture or
adhesive.
Example 2
[0164] In another exemplary embodiment for treating a herniated
disc, a guide wire may be guided with fluoroscopic imaging to a
position at the specific site of herniation. The guide wire may
include markers which can be observed via X-ray and a bevel tip on
the distal end and be made of a material having elastic or shape
memory characteristics with a curvature at its' distal end. The
guide wire may then be used to easily and accurately navigate to
the herniation site to create a pathway for subsequent devices to
follow to the herniation site. The Guide Wire may then be left in
place to serve as a guide to the herniation site or subsequently
inserted devices may follow the pathway left by the guide wire. The
guide wire may be left in place or removed and the herniation site
debulked as described in Example 1.
Example 3
Direct Visualization
[0165] In general, a patient is examined and diagnosed with a
herniated disc. Although direct visualization is to be used,
imaging technology such as MRI or an X-ray device may still be used
to locate the position of the herniated disc and the position may
be marked on the patient.
[0166] An introducer such as a hypodermic needle is provided that
is inserted in a patient's body so that its distal end creates an
annular opening leading to the nucleus pulposus. A guide wire is
slid into position within and through the introducer lumen so that
a distal tip of the guide wire is positioned at the selected
location within the nucleus by advancing or retracing the guide
wire in the introducer lumen and optionally twisting the proximal
end of the guide wire to precisely navigate the guide wire.
[0167] A small incision is then made in the patient's skin and
subcutaneous tissue which facilitates access of a dilator sheath.
The introducer is then removed and the dilator sheath is advanced
over the guide wire to dilate the incision from the patient's skin
to the intervertebral disc. The dilator sheath abuts the disc but
does not penetrate the disc.
[0168] Next, a cannula having at least one lumen is slid over the
sheath and navigated to the distal most portion of the guide wire
within the nucleus and the guide wire and cannula are removed from
the lumen of the cannula. Alternatively, the cannula may be
advanced to abut the disc annulus, the guide wire and dilator are
removed from the lumen, and a trocar is advanced through the lumen
of the cannula to pierce the disc annulus and gain entry to the
nucleus. Direct visualization is used to position the cutting
component at the herniation.
[0169] A cutting device of the present invention is advanced
through the lumen of the cannula. As the cutting device advances,
it follows a curved path to the site of disc herniation because the
distal portion of the subject device is configured to curve away
from the distal end of the cannula towards the posterior wall of
the annulus. The distal tip of the cutting device is configured to
minimize the possibility of piercing the wall of the annulus from
the inside.
[0170] The subject cutting device will be advanced using direct
visualization until the open window of the cutting window (45) is
directly positioned at the target site as illustrated in FIG. 7. In
certain aspects, the target site is a specific site within the
nucleus. In other aspects, the specific target site is the specific
site of herniation within the fissure. A vacuum may be applied to
remove blood or material blocking direct visualization. The vacuum
is then used to draw tissue into the open window in the anvil. The
Cutter 30 of the subject device will be advanced to slide towards
the distal end of the Anvil 40, thereby cutting any nucleus
pulposus material present in the open window (45). Direct
visualization can be used to determine if the herniation has been
removed. In some embodiments, the flexible shaft includes a lumen
which communicates with a vacuum source to draw tissue into the
cutting window of the anvil. The subject cutting device excises
tissue until the disc herniation has been adequately debulked. The
subject device is then withdrawn from the cannula and the entry
site is closed with a suture or adhesive.
Example 4
[0171] In another exemplary embodiment for treating a herniated
disc, a guide wire is positioned at the specific site of herniation
using direct visualization. The guide wire may include a bevel tip
on the distal end and be made of a material having elastic or shape
memory characteristics. The guide wire may then be used to easily
and accurately navigate to the herniation site to create a pathway
for subsequent devices to follow to the herniation site. The Guide
Wire may then be left in place to serve as a guide to the
herniation site or subsequently inserted devices may follow the
pathway left by the guide wire. The guide wire may be left in place
or removed and the herniation site debulked as described in Example
3.
Use with Jig
[0172] In certain embodiments, a jig is employed to hold the
cannula in place on the patient's skin. By using a jig, the patient
is able to move during the procedure while the cannula and cutting
device remains in place. Aspects of this embodiment include
attaching the jig to the patient or the bed via an adhesive or
screw. In this embodiment, calculations are performed to determine
reference points to define the proper plane in which the cannula
should be positioned to allow for access to the posterior wall of
the annulus within the confines of the nucleus. Methods for
employing a jig in surgical methods are provided in U.S. Pat. Nos.
5,251,127, 5,305,203, 5,086,401, 5,299,288 and 5,408,409, the
disclosures of which are herein incorporated. In a particular
embodiment, the jig may be attached to the cannula or cutting
device after they are in position within the disc and the proper
position of the cannula has been defined.
[0173] A medical practitioner may require or find it useful to
precisely position the cutting device of the invention when
performing surgery on a patient. To do such patient data may be
developed which identifies the position and orientation of a
particular target site such as the site of herniation which is to
be removed. The position and orientation of the cutting device of
the invention is sensed and instrument data is developed from the
sensing. The patient data is converted to objective signals which
may be displayed on a video display. The instrument data may be
converted to instrument signals for presenting the position and
orientation of the cutting device of the invention. Accordingly, by
watching the displays the medical practitioner may be aided in the
manipulation and maneuvering of the distal end of the cutting
device of the invention in order to move it into precise position
beside the site of herniation. Methodologies and devices which aid
in sensing and obtaining such data and positioning the instrument
are described in publications such as U.S. Pat. No. 5,251,127
issued Oct. 5, 1993.
Kits
[0174] Also provided are kits for practicing the present methods.
The present kits may vary greatly in regards to the components that
are included in the kit. The present kits at least include a
subject cutting device for use in practicing the present
methods.
[0175] The present kits may also include radiopaque dye to be
injected into the operative site for visualization purposes. For
example, the subject kits may include dilute barium sulphate
solution, bismuth trioxide, iodine, iodide, titanium oxide,
zirconium oxide, metals such as gold, platinum, silver, tantalum,
niobium, stainless steel, and combinations thereof.
[0176] In certain embodiments, the subject kits may additionally
include a medicament to be delivered within the disc. For example,
the kits may include a pharmaceutical agent, chemonucleolytic
enzymes, hydrogel substances, osteoinductive substances,
chondrocyte-inductive substances, sealants, collagen, fibrinogen,
thrombin and combinations thereof.
[0177] In some embodiments, the subject kits may further include a
liquid jet device and a liquid solution to be delivered into the
nucleus. For example, the kits may include saline solution or
sterile water.
[0178] In a particular embodiment, the subject devices may include
stylets and control wires for adjusting the curvature of the
subject devices. Aspects of this embodiment include 2, 3, 4 or more
stylets that have degrees of curvatures relative to each other
which allow for the subject cutting devices to accordingly have
varying ranges of curvatures.
[0179] In a particular embodiment, the kits may include a jig to
hold the cannula and/or the cutting devices in a fixed position
relative to the patient.
[0180] In a particular embodiment, the kits may include the
components required to gain access to the disk such as the Guide
Wire, Dilator, Cannula, and Trocar.
[0181] The preceding merely illustrates the principles of the
invention. It will be appreciated that those skilled in the art
will be able to devise various arrangements which, although not
explicitly described or shown herein, embody the principles of the
invention and are included within its spirit and scope.
Furthermore, all examples and conditional language recited herein
are principally intended to aid the reader in understanding the
principles of the invention and the concepts contributed by the
inventors to furthering the art, and are to be construed as being
without limitation to such specifically recited examples and
conditions. Moreover, all statements herein reciting principles,
aspects, and embodiments of the invention as well as specific
examples thereof, are intended to encompass both structural and
functional equivalents thereof. Additionally, it is intended that
such equivalents include both currently known equivalents and
equivalents developed in the future, i.e., any elements developed
that perform the same function, regardless of structure. The scope
of the present invention, therefore, is not intended to be limited
to the exemplary embodiments shown and described herein. Rather,
the scope and spirit of present invention is embodied by the
appended claims.
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