Source: http://www.docstoc.com/docs/55124332/Method-And-Apparatus-For-Treating-Annular-Fissures-In-Intervertebral-Discs---Patent-6997941
Timestamp: 2014-08-21 21:04:45
Document Index: 324055605

Matched Legal Cases: ['application No.\n60', 'application No. 60', 'application No. 60', 'application No. 60', 'application No.\n60', 'application No.\n60']

Method And Apparatus For Treating Annular Fissures In Intervertebral Discs - Patent 6997941
United States Patent: 6997941
6,997,941
A device is described that may be positioned at a location in an
intervertebral disc for diagnosis or treatment of the disc. Treatment may
include, for example, applying energy or removing material, and may
decrease intradiscal pressure. Radiofrequency energy may be applied. A
percutaneous method of repairing a fissure in the annulus pulposus
comprises placing an energy source adjacent to the fissure and providing
sufficient energy to the fissure to raise the temperature to at least
about 45-70.degree. C. and for a sufficient time to cause the collagen to
weld. An intervertebral fissure also can be treated by placing a catheter
with a lumen adjacent to the fissure and injecting sealant into the
fissure via the catheter, thereby sealing the fissure. An intervertebral
fissure additionally can be treated by providing a catheter having a
distal end, a proximal end, a longitudinal axis, and an intradiscal
section at the catheter&#39;s distal end on which there is at least one
functional element. The next step is applying a force longitudinally to
the proximal of the catheter which is sufficient to advance the
intradiscal section through the nucleus pulposus and around an inner wall
of an annulus fibrosus, but which force is insufficient to puncture the
annulus fibrosus. Next the functional element is positioned at a selected
location of the disc by advancing or retracting the catheter and
optionally twisting the proximal end of the catheter. Then the functional
unit treats the annular fissure. Optionally, there is an additional step
of adding a substance to seal the fissure. An externally guidable
intervertebral disc apparatus also is disclosed.
Sharkey; Hugh R. (Woodside, CA), Ashley; John (San Francisco, CA), Saal; Joel (Portola Valley, CA), Saal; Jeffrey A. (Portola Valley, CA), Le; Le Trong (San Jose, CA)
10/388,609
09707627Nov., 20006547810
09236816Jan., 19996290715
09162704Sep., 19986099514
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607/96  ; 606/48; 606/50; 607/113; 607/116; 607/99
607/96,113,116,98,100,101,102,117,89,99 606/48,50,27,28,29,30,31,32,2,13,14,41 128/898 600/373
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No. 09/707,627, filed Nov. 6, 2000, now U.S. Pat. No. 6,547,810 which is
a continuation of U.S. patent application Ser. No. 09/236,816, filed Jan
25, 1999, now U.S. Pat. No. 6,290,715, and a continuation-in-part of U.S.
patent application Ser. No. 09/162,704, filed Sep. 29, 1998, now U.S.
Pat. No. 6,099,514, U.S. patent application Ser. No. 09/153,552, filed
Sep. 15, 1998, now U.S. Pat. No. 6,126,682, U.S. patent application Ser.
No. 08/881,525, filed Jun. 24, 1997, now U.S. Pat. No. 6,122,549, U.S.
patent application Ser. No. 08/881,692, filed Jun. 24, 1997, now U.S.
Pat, No. 6,073,051, U.S. patent application Ser. No. 08/881,527, filed
Jun. 24, 1997, now U.S. Pat. No. 5,980,504, U.S. patent application Ser.
No. 08/881,693, filed Jun. 24, 1997, now U.S. Pat. No. 6,007,570, U.S.
patent application Ser. No. 08/881,694, filed Jun. 24, 1997, now U.S.
Pat. No. 6,095,149, and which claims priority to provisional application
No. 60/047,820, filed May 28, 1997, provisional application No.
60/047,841, filed May 28, 1997, provisional application No. 60/047,818,
filed May 28, 1997, provisional application No. 60/047,848, filed May 28,
1997, provisional application No. 60/045,941, filed May 8, 1997,
provisional No. 60/029,734, filed Oct. 23, 1996, provisional application
No. 60/029,735, filed Oct. 23, 1996, provisional application No.
60/029,600, filed Oct. 23, 1996, and provisional application No.
60/029,602, filed Oct. 23, 1996, each of which are incorporated herein by
This application is related to the following applications and the
applications to which they claim priority: &quot;Method and Apparatus for
Treating Intervertebral Discs with Thermal Energy&quot;, by the same inventors
as named for this application, filed on Jun. 24, 1997, and identified as
Ser. No. 08/886,525; &quot;Method and Apparatus for Treating Intervertebral
Discs with Electrothermal Energy&quot;, by the same inventors as named for
this application, filed on Jun. 24, 1997, and identified as Ser. No.
08/881,692; &quot;Method and Apparatus for Delivering and Removing Material
from the Interior of an Intervertebral Disc&quot;, by the same inventors as
named for this application, filed on Jun. 24, 1997, and identified as
Ser. No. 08/881,527; and &quot;Method and Apparatus for Treating
Intervertebral Disc Degeneration&quot;, by the same inventors as named for
08/881,694. The above applications are incorporated by reference.
1.  A device for treating an intervertebral disc, the device comprising: an introducer including a needle, the introducer defining an introducer lumen, and the introducer
having sufficient rigidity to penetrate an annulus fibrosus of an intervertebral disc;  and a catheter configured to be inserted through the introducer lumen and into the intervertebral disc, the catheter having a distal region including a bipolar
radiofrequency electrode configuration, the distal region having sufficient column strength to be advanced by blunt dissection through a nucleus pulposus of the intervertebral disc to an inner wall of the annulus fibrosus and sufficient rigidity in a
direction out of a disc plane of the intervertebral disc to substantially inhibit bending in the direction.
2.  The device of claim 1 wherein the needle comprises a 17-gauge needle.
3.  The device of claim 1 or 2 wherein the introducer comprises a trocar.
4.  The device of claim 1 wherein the catheter has a proximal region and the catheter has sufficient torsional strength to transmit rotation applied at the proximal region to the distal region, with the distal region located in the nucleus
pulposus of the intervertebral disc.
5.  The device of claim 1 wherein the catheter has a total length between 5 and 24 inches.
6.  The device of claim 1 or 5 wherein the catheter is configured to be extended from the introducer a maximum distance of no greater than one and one-half times the circumference of the nucleus pulposus.
7.  The device of claim 1 or 5 wherein the distal region comprises a biased region that permits advancement of the catheter from the introducer into the intervertebral disc in substantially only one lateral direction relative to a longitudinal
axis of the introducer.
8.  The device of claim 7 wherein the catheter has a proximal region and the catheter has sufficient torsional strength to transmit rotation applied at the proximal region to the distal region, with the distal region located in the nucleus
9.  The device of claim 1 wherein the direction out of the disc plane comprises a direction orthogonal to the disc plane.
10.  The device of claim 1 wherein the direction out of the disc plane comprises a direction along an axis defined by a spinal column.
11.  A kit for treating an intervertebral disc, the kit comprising: a needle and a trocar;  and a catheter configured to be inserted through the needle and into the intervertebral disc, the catheter having a distal region including a bipolar
12.  The device of claim 1 or 4 wherein the bipolar radiofrequency electrode configuration includes an active electrode and a return electrode, and the catheter further comprises a second active electrode.
13.  The device of claim 1 wherein the catheter is further configured to conform sufficiently to the inner wall of the annulus fibrosus to contact multiple locations on the inner wall.
14.  The device of claim 1 wherein the distal region of the catheter is configured to provide differential flexibility between the direction and at least one other direction.
15.  The device of claim 14 wherein the catheter comprises a mandrel that provides the differential flexibility.
16.  The device of claim 15 wherein at least a portion of the mandrel has a rectangular cross-section.
17.  The device of claim 15 wherein at least a portion of the mandrel has a D-shaped cross-section.
18.  The device of claim 15 wherein at least a portion of the mandrel has an oval cross-section.
19.  The device of claim 2 wherein the catheter includes a sheath on at least a portion of an outer surface of the catheter.
20.  The device of claim 19 wherein the sheath is formed of a polyimide material.
21.  The device of claim 20 wherein the bipolar electrode configuration is disposed distal to a portion of the sheath.
22.  The device of claim 21 wherein the catheter is configured to provide preferential localized heating so that water is removed from the nucleus pulposus.
23.  The device of claim 21 further comprising a visible marker that is configured to show rotation of the catheter during use.
24.  The device of claim 23 wherein the visible marker is disposed on a proximal end of the catheter.
25.  The device of claim 2 further comprising a handle attached to a proximal end of the catheter, wherein the catheter includes a bend at the distal region and the handle includes a marker aligned with the bend.
26.  The device of claim 25 wherein the catheter is adapted to be twisted at the handle to adjust a position within the nucleus pulposus of one or more electrodes in the bipolar radiofrequency electrode configuration.
27.  The device of claim 26 wherein the catheter is adapted to be advanced through the nucleus pulposus and is configured to remove nucleus tissue by application of RF energy.
28.  The device of claim 2 further comprising a handle adapted to allow the device to be gripped during a procedure, and wherein (i) the device is configured so that the handle can be used to adjust a position within the nucleus pulposus of one
or more electrodes in the bipolar radiofrequency electrode configuration, and (ii) the device is configured to remove nucleus tissue by application of RF energy.
29.  The device of claim 28 wherein the device is adapted to provide preferential local heating of the nucleus tissue.
30.  The device of claim 29 wherein the preferential local heating of the nucleus tissue is adapted to remove at least water from the disc to decompress the disc.
31.  The device of claim 2 wherein (i) the catheter includes a tube that provides stiffness to the catheter, (ii) the catheter includes a sheath disposed on at least a portion of the catheter, and (iii) a part of the radiofrequency electrode
configuration is disposed distal to the sheath.
32.  The device of claim 2 wherein an outer diameter of the catheter is between approximately 0.2 mm and approximately 5 mm.
33.  The device of claim 32 wherein a total length of the catheter is between approximately 10 cm and approximately 60 cm.
34.  The device of claim 33 wherein the total length of the catheter is between approximately 10 cm and approximately 30 cm.
35.  The device of claim 34 wherein the catheter comprises a round metallic tube.
36.  The device of claim 35 wherein one or more electrodes in the bipolar radiofrequency electrode configuration is disposed distal to the metallic tube.
37.  The device of claim 36 wherein the catheter includes a polyimide sheath in addition to the metallic tube.
38.  The kit of claim 11 wherein the catheter includes a sheath on at least a portion of an outer surface of the catheter.
39.  The kit of claim 38 wherein the sheath is formed of a polyimide material.
40.  The kit of claim 39 wherein the bipolar electrode configuration is disposed distal to a portion of the sheath.
41.  The kit of claim 40 wherein the catheter is configured to provide preferential localized heating so that water is removed from the nucleus pulposus.
42.  The kit of claim 41 wherein the catheter includes a visible marker that is configured to show rotation of the catheter during use.
43.  The kit of claim 42 wherein the visible marker is disposed on a proximal end of the catheter.
44.  The kit of claim 11 further comprising a handle attached to a proximal end of the catheter, wherein the catheter includes a bend at the distal region and the handle includes a marker aligned with the bend.
45.  The kit of claim 44 wherein the catheter is adapted to be twisted at the handle to adjust a position within the nucleus pulposus of one or more electrodes in the bipolar radiofrequency electrode configuration.
46.  The kit of claim 44 wherein the catheter is adapted to be advanced through the nucleus pulposus and is configured to remove nucleus tissue by application of RF energy.
47.  The kit of claim 11 further comprising a handle attached to the catheter that is adapted to allow the catheter to be gripped during a procedure, and wherein (i) the catheter is configured so that the handle can be used to adjust a position
within the nucleus pulposus of one or more electrodes in the bipolar radiofrequency electrode configuration, and (ii) the device is configured to remove nucleus tissue by application of RF energy.
48.  The kit of claim 47 wherein the catheter is adapted to provide preferential local heating of the nucleus tissue.
49.  The kit of claim 48 wherein the preferential local heating of the nucleus tissue is adapted to remove at least water from the disc to decompress the disc.
50.  The kit of claim 49 wherein (i) the catheter includes a tube that provides stiffness to the catheter, (ii) the catheter includes a sheath disposed on at least a portion of the catheter, and (iii) a part of the radiofrequency electrode
configuration is disposed distal to the sheath.  Description
Disc fissures occur rather easily after structural degeneration (a part of the aging process that may be accelerated by trauma) of fibrous components of the annulus fibrosus.  Sneezing, bending or just attrition can tear these degenerated annulus
rest, pain killers and muscle relaxants.  More recently spinal fusion with cages have been performed when conservative treatment did not relieve the pain.  The fissure may also be associated with a herniation of that portion of the annulus.
reduced and the joint may become unstable.  One vertebra may settle on top of another.  This problem continues as the body ages and accounts for shortened stature in old age.  With the increasing life expectancy of the population, such degenerative disc
disease and impairment of nerve function are becoming major public health problems.  As the disc &quot;roll&quot; extends beyond the normal circumference, the disc height may be compromised, foramina with nerve roots are compressed.  In addition, osteophytes may
form on the outer surface of the disc roll and further encroach on the spinal canal and foramina through which nerves pass.  This condition is called lumbar spondylosis.
form a single, solid piece of bone.  The procedure is carried out with or without discectomy.  Other treatments include discectomy alone or disc decompression with or without fusion.  Nuclectomy can be performed by removing some of the nucleus to reduce
demonstrated success rates of between 50% and 67% for pain improvement, and a significant number of patients have more pain postoperatively.  Therefore, different methods of helping patients with degenerative disc problems need to be explored.
longitudinal ligament; 126--vertebral body; 128--pedicle; 130--vertebral artery; 132--vertebral veins; 134--superior articular facet; 136--posterior lateral portion of the annulus; 138--posterior medial portion of the annulus; and 142--spinous process.
In FIG. 1(a), one side of the intervertebral disc 118 is not shown so that the anterior vertebral body 126 can be seen.  FIG. 1(b) is a lateral aspect of the lower portion of a typical spinal column showing the entire lumbar region and part of the
thoracic region and displaying the following structures: 118--intervertebral disc; 126--vertebral body; 142--spinous process; 170--inferior vertebral notch; 110--spinal nerve; 174--superior articular process; 176--lumbar curvature; and 180--sacrum.
is important because the posterior disc wall is the site of symptomatic annulus tears and disc protrusions/extrusions that compress or irritate spinal nerves for most degenerative disc syndromes.  The inferior articular process, along with the pedicle
and the lumbar spinal nerve, form a small &quot;triangular&quot; window (shown in black in FIG. 1(c)) through which introduction can be achieved from the posterior lateral approach.  FIG. 1(d) looks down on an instrument introduced by the posterior lateral
approach.  It is well known to those skilled in the art that percutaneous access to the disc is achieved by placing an introducer into the disc from this posterior lateral approach, but the triangular window does not allow much room to maneuver.  Once
the introducer pierces the tough annulus fibrosus, the introducer is fixed at two points along its length and has very little freedom of movement.  Thus, this approach has allowed access only to small central and anterior portions of the nucleus
pulposus.  Current methods do not permit percutaneous access to the posterior half of the nucleus or to the posterior wall of the disc.  Major and potentially dangerous surgery is required to access these areas.
RF electrode to pierce the annulus fibrosus, and the ability to maneuver its distal end within the nucleus pulposus is limited.  In another embodiment, a somewhat more flexible shaft is disclosed.  However, neither embodiment of the devices of the &#39;739
patent permits access to the posterior, posterior lateral and posterior medial region of the disc, nor do they provide for focal delivery of therapy to a selected local region within the disc or precise temperature control at the annulus.  The &#39;739
patent teaches the relief of pain by globally heating the disc.  There is no disclosure of treating an annular tear or fissure.
U.S.  Pat No. 5,201,729 (the &quot;&#39;729 patent&quot;) discloses use of an optical fiber that is introduced into a nucleus pulposus.  In the &#39;729 patent, the distal end of a stiff optical fiber shaft extends in a lateral direction relative to a longitudinal
axis of an introducer.  This prevents delivery of coherent energy into the nucleus pulposus in the direction of the longitudinal axis of the introducer.  Due to the constrained access from the posterior lateral approach, stiff shaft and lateral energy
delivery, the device of the &#39;729 patent is unable to gain close proximity to seelected portion(s) of the annulus (i.e., posterior, posterior medial and central posterior) requiring treatment or to precisely control the temperature at the annulus.  No use
in treating an annular fissuer is disclosed.  The device of the &#39;729 patent describes ablating the nucleus pulposus.
Accordingly, it is desirable to diagnose and treat disc abnormalities at locations previously not accessible via percutaneous approaches and without substantial destruction to the disc.  It would further be desirable to be able to administer
materials to a precise, selected location within the disc, particularly to the location of the annular fissure.  It would be further desirable to provide thermal energy into collagen in the area of the fissure to strengthen the annulus and possibly fuse
collagen to the sides of the fissure, particularly at the posterior, posterior lateral and the posterior medial regions of the inner wall of the annulus fibrosus.
Still a further aspect features a device which has a distal end that is inserted into the disc and accesses the posterior, posterior lateral and the posterior medial regions of the inner wall of the annulus fibrosus in order to repair or shrink
an annular fissure at such a location.
Methods for manipulating a disc tissue with a fissure or tear in an intervertebral disc, the disc having a nucleus pulposus and an annulus fibrosus, the annulus having an inner wall of the annulus fibrosus, employs employ an externally guidable
intervertebral disc apparatus, or catheter.  The procedure is performed with a catheter having a distal end, a proximal end, a longitudinal axis, and an intradiscal section at the catheter&#39;s distal end on which there is at least one functional element.
The catheter is advanced through the nucleus pulposus and around an inner wall of an annulus fibrosus by applying a force to the proximal end, but the applied force is insufficient for the intradiscal section to puncture the annulus fibrosus.  The next
step is positioning the functional element at a selected location of the disc by advancing or retracting the catheter and optionally twisting the proximal end of the catheter.  Then the functional unit treats the annular fissure.
A method of treating an intervertebral fissure includes placing an energy source adjacent to the fissure and providing sufficient energy to the fissure to raise the temperature to at least about 45-70.degree.  C. and for a sufficient time to
cause the collagen to weld.
In addition to the methods, there is provided an externally guidable intervertebral disc apparatus for diagnosis or manipulation of the disc tissue present at a selected location of an intervertebral disc, the disc having a nucleus pulposus, an
annulus fibrosus, an inner wall of the annulus fibrosus, the nucleus pulposus having a diameter in a disc plane between opposing sections of the inner wall.  The apparatus comprises a catheter having a distal end, a proximal end, and a longitudinal axis,
and an intradiscal section at the catheter&#39;s distal end, which is extendible into the disc, has sufficient rigidity to be advanceable through the nucleus pulposus and around the inner wall of the annulus fibrosus under a force applied longitudinally to
the proximal end, has sufficient flexibility in a direction of the disc plane to be compliant with the inner wall, and has sufficient penetration ability to be advanceable out through the annulus fibrosus under the force; and a functional element located
at the intradiscal section for adding sufficient thermal energy at or near the fissure.
According to another aspect of the invention, an intervertebral disc apparatus includes an introducer and a catheter.  The introducer includes an introducer lumen.  The catheter is at least partially positionable in the introducer lumen.  The
catheter includes an intradiscal section and an energy delivery device coupled to the intradiscal section.  The intradiscal section is configured to be advanceable through a nucleus pulposus of the intervertebral disc and positionable adjacent to a
selected site of an inner wall of an annulus fibrosus.  Embodiments of this aspect may include that the energy delivery device is configured to deliver sufficient energy to, e.g., create a selected ablation of a selected site of the intervertebral disc,
reduce an intradiscal pressure of the intervertebral disc, and/or provide a denervation of a nerve at a selected site of the intervertebral disc.  The energy delivery device includes, e.g., an RF electrode configured to be coupled to an RF energy source.
According to another aspect of the invention, a method of treating back or neck pain includes providing a catheter deployable from an introducer lumen, the catheter including an intradiscal section coupled to an energy delivery device, wherein
the intradiscal section is advanceable through a nucleus pulposus and positionable along a selected site of an inner wall of an annulus fibrosus.  The method includes advancing the intradiscal section into the nucleus pulposus from a distal end of the
introducer lumen and positioning at least a portion of the intradiscal section along at least a portion of the inner wall of the annulus fibrosus to the selected site.  Embodiments of this aspect may include delivering sufficient energy from the energy
delivery device to, e.g., create a selected ablation of a selected site of the intervertebral disc, reduce an intradiscal pressure of the intervertebral disc and/or denervate a nerve of the intervertebral disc.
Another aspect features an intervertebral disc apparatus including a catheter at least partially positionable in an introducer lumen.  The catheter includes an intradiscal section and an energy delivery device coupled to the intradiscal section.
The intradiscal section is configured to be advanceable through a nucleus pulposus of the intervertebral disc and navigationable along an inner wall of an annulus fibrosus.  Embodiments of this aspect of the invention may include multiple electrodes that
operate in a bipolar mode.
The details of one or more embodiments are set forth in the drawings and the description below.  Other features will be apparent from the description and drawings, and from the claims.
The present invention provides a method and apparatus for diagnosing and treating intervertebral disc disorders, such as, for example, tears of fissures of the annulus fibrosus, herniations, and circumferential bulging, which may or may not be
accompanied with contained or escaped extrusions.
In general, an apparatus of the invention is in the form of an externally guidable intervertebral disc apparatus for accessing and manipulating disc tissue present at a selected location of an intervertebral disc having a nucleus pulposus and an
annulus fibrosus, the annulus having an inner wall.  Use of a temperature-controlled energy delivery element, combined with the navigational control of the inventive catheter, provides preferential, localized heating to treat the fissure.  For ease of
reference to various manipulations and distances described below, the nucleus pulposus can be considered as having a given diameter in a disc plane between opposing sections of the inner wall.  This nucleus pulposus diameter measurement allows instrument
sizes (and parts of instruments) designed for one size disc to be readily converted to sizes suitable for an instrument designed for a different size of disc.
The operational portion of the apparatus of the invention is brought to a location in or near the disc&#39;s fissure using techniques and apparatuses typical of percutaneous interventions.  For convenience and to indicate that the apparatus of the
invention can be used with any insertional apparatus that provides proximity to the disc, including many such insertional apparatuses known in the art, the term &quot;introducer&quot; is used to describe this aid to the method.  An introducer has an internal
introducer lumen with a distal opening at a terminus of the introducer to allow insertion (and manipulation) of the operational parts of the apparatus into (and in) the interior of a disc.
end closest to the external environment surrounding the body being operated upon (which may still be inside the body in some embodiments if the catheter is attached to a handle insertable into the introducer).  The distal end of the catheter is intended
to be located inside the disc under conditions of use.  The catheter is not necessarily a traditional medical catheter (i.e., an elongate hollow tube for admission or removal of fluids from an internal body cavity) but is a defined term for the purposes
of this specification.  &quot;Catheter&quot; has been selected as the operant word to describe this part of the apparatus, as the inventive apparatus is a long, flexible tube which transmits energy and/or material from a location external to the body to a location
internal to the disc being accessed upon, such as a collagen solution and heat to the annular fissure.  Alternatively, material can be transported in the other direction to remove material from the disc, such as removing material by aspiration to
decrease pressure which is keeping the fissure open and aggravating the symptoms due to the fissure.  Material may be removed to decrease intradiscal pressure which maintains a herniation.
In order that the functional elements of the catheter can be readily guided to the desired location within a disc, the intradiscal portion of the catheter is manufactured with sufficient rigidity to avoid collapsing upon itself while being
advanced through the nucleus pulposus and navigated around the inner wall of the annulus fibrosus.  The intradiscal portion, however, has insufficient rigidity to puncture the annulus fibrosus under the same force used to advance the catheter through the
nucleus pulposus and around the inner wall of the annulus fibrosus.  Absolute penetration ability will vary with sharpness and stiffness of the tip of the catheter, but in all cases a catheter of the present invention will advance more readily through
the nucleus pulposus than through the annulus fibrosus.
at random).  Also when a torsional (twisting) force is applied to the proximal end of the catheter to re-orient the distal end of the catheter, controlled advancement of the catheter in the desired plane is possible.
A further component of the catheter is a functional element located in the intradiscal section for diagnosis or for adding energy and adding and/or removing material at the selected location of the disc where the annular tear is to be treated, or
some other therapeutic action is to be carried out.  The apparatus allows the functional element to be controllably guided by manipulation of the proximal end of the catheter into a selected location for localized diagnosis and/or treatment of a portion
of the disc, such as, for example, the annular fissure.
The method of the invention which involves manipulating disc tissue at the annular fissure or other selected location, is easily carried out with an apparatus of the invention.  An introducer is provided that is located in a patient&#39;s body so
that its proximal end is external to the body and the distal opening of its lumen is internal to the body and (1) internal to the annulus fibrosus or (2) adjacent to an annular opening leading to the nucleus pulposus, such as an annular tear or trocar
puncture that communicates with the nucleus pulposus.  The catheter is then slid into position in and through the introducer lumen so that the functional element in the catheter is positioned at the selected location of the disc by advancing or
retracting the catheter in the introducer lumen and optionally twisting the proximal end of the catheter to precisely navigate the catheter.  By careful selection of the rigidity of the catheter and by making it sufficiently blunt to not penetrate the
annulus fibrosus, and by careful selection of the flexibility in one plane versus the orthogonal plane, the distal portion of the catheter will curve along the inner wall of the annulus fibrosus as it is navigated and is selectively guided to an annular
tear or other selected location(s) in the disc.  Energy is applied and/or material is added or removed at the selected location of the disc via the functional element.
The annulus fibrosus is comprised primarily of tough fibrous material, while the nucleus pulposus is comprised primarily of an amorphous colloidal gel.  There is a transition zone between the annulus fibrosus and the nucleus pulposus made of both
fibrous-like material and amorphous colloidal gel.  The border between the annulus fibrosus and the nucleus pulposus becomes more difficult to distinguish as a patient ages, due to degenerative changes.  This process may begin as early as 30 years of
(hereafter collectively referred to as the &quot;inner wall of the annulus fibrosus&quot;).  Functionally, that location at which there is an increase in resistance to catheter penetration and which is sufficient to cause bending of the distal portion of the
catheter into a radius less than that of the internal wall of the annulus fibrosus is considered to be the &quot;inner wall of the annulus fibrosus&quot;.
Stages of Disc Degeneration as Revealed by Discograms, &quot; J. Bone and Joint Surgery, 68, 36-41 (1986).  As these grades are commonly understood, the methods of instrument navigation described herein would probably not be able to distinguish between the
Some of the following discussion refers to motion of the catheter inside the disc by use of the terms &quot;disc plane&quot; &quot;oblique plane&quot; and &quot;cephalo-caudal plane.&quot; These specific terms refer to orientations of the catheter within the intervertebral
disc.  Referring now to FIG. 2 (which shows a vertical cross-section of a disc), a disc plane 30 of the intervertebral disc is generally a plane of some thickness 27 within the nucleus pulposus 120 orthogonal to the axis formed by the spinal column
(i.e., such a disc plane is substantially horizontal in a standing human, corresponding to the &quot;flat&quot; surface of a vertebra).  A oblique plane 31 extends along any tilted orientation relative to axial plane 30; however, when the plane is tilted
90.degree., such a plane would be substantially vertical in a standing human and is referred to as a cephalo-caudal plane.  Reference is made to such planes to describe catheter movements with respect to the disc plane.  In various embodiments, disc
plane 30 has a thickness no greater than the thickness of the intervertebral disc, preferably a thickness no greater than 75% of a thickness of the intervertebral disc, and more preferably a thickness no greater than 50% of a thickness of the
intervertebral disc.  Movement of the intradiscal portion 16 of catheter 14 is confined within a disc plane by the physical and mechanical properties of the intradiscal portion 16 during advancement of the catheter when the bending plane of the catheter
is aligned with the disc plane until some additional force is applied to the catheter by the physician.  A twisting force (which can be applied mechanically, electrically, or by any other means) acting on the proximal end of the catheter changes the
forces acting on the distal end of the catheter so that the plane of the catheter bend can be angled relative to the disc plane as the catheter is advanced.  Thus, the physician can cause the distal end of the catheter to move up or down, depending on
the direction of the twist.
Turning now to the introducer, a detailed description of an entire apparatus should not be necessary for those skilled in the art of percutaneous procedures and the design of instruments intended for such use.  The method of the invention can
also be carried out with endoscopic instruments, and an endoscopic apparatus having structural parts that meet the descriptions set forth in this specification would also be an apparatus of the invention.
In general, a device of the invention can be prepared in a number of different forms and can consist (for example) of a single instrument with multiple internal parts or a series of instruments that can be replaceably and sequentially inserted
into a hollow fixed instrument (such as a needle) that guides the operational instruments to a selected location, such as, for example, an annular fissure, in or adjacent to an intervertebral disc.  Because prior patents do not fully agree on how to
describe parts of percutaneous instruments, terminology with the widest common usage will be used.
catheter that will be pushed out of the introducer lumen and into the nucleus pulposus, where movement of the catheter will be controlled to bring operational portions of the catheter into the selected location(s) within the disc, such as, for example,
the annular tear.  In FIG. 3(a), dashed lines are used to illustrate bending of the intradiscal portion of the catheter as it might appear under use, as discussed in detail later in the specification.  FIG. 3(b) shows an end view of handle 11 at the
proximal end of the catheter, with the handle 11 having an oval shape to indicate the plane of bending, also discussed in detail later in the specification.  Other sections and properties of catheter 14 are described later.
can insert the catheter for a distance sufficient to reach selected location(s) in the nucleus of a human intervertebral disc.
FIG. 4 illustrates the anatomy of an intervertebral disc and shows an apparatus of the invention inserted into a disc.  Structures of the disc are identified and described by these anatomical designations: the posterior lateral inner annulus 136,
posterior medial inner annulus 138, annulus fibrosus 122/nucleus pulposus 120 interface, the annulus/dural interface 146, annulus/posterior longitudinal ligament interface 148, anterior lateral inner annulus 150, and the anterior medial inner annulus
flexural strengths along the two axes orthogonal to the longitudinal axis to allow controlled bending of the catheter.  These parameters make the catheter conformable and guidable along inner wall 22 of an annulus fibrosus 122 to reach selected
location(s), such as the posterior medial annulus 138.
section of the catheter with sufficient column strength to be advanceable through normal human nucleus pulposus and around the inner wall of the annulus fibrosus without collapse.  Here &quot;collapse&quot; refers to bending sufficient to inhibit further
advancement at the tip.  Advancement of the tip is restricted by 1) sliding through the normal gelatinous nucleus pulposus, 2) contacting denser clumps of nucleus pulposus, and 3) curving and advancing along the inner wall of the annulus.  Column
strength can be increased in many ways known in the art, including but not limited to selecting materials (e.g., metal alloy or plastic) with a high resistance to bending from which to form the catheter, forming the structure of the catheter with
When the catheter collapses, the physician feels an abrupt decrease in resistance.  At that time, the catheter forms one or more loops or kinks between the tip of the introducer and the distal tip of the catheter.
Particularly preferred for locations, such as, for example, annular tears, at the posterior of the annulus, the tip 28 of intradiscal section 16 is biased or otherwise manufactured so that it forms a pre-bent segment prior to contact with the
annulus fibrosus as shown in FIG. 3(a).  The bent tip will cause the intradiscal section to tend to continue to bend the catheter in the same direction as the catheter is advanced.  This enhanced curving of a pre-bent catheter is preferred for a catheter
that is designed to reach a posterior region of the nucleus pulposus; however, such a catheter must have sufficient column strength to prevent the catheter from collapsing back on itself.
The intradiscal section not only must allow bending around the relatively stronger annulus fibrosus in one direction, but also resist bending in the orthogonal direction to the plane in which bending is designed to occur.  By twisting the
The bending stiffness of the intradiscal section as measured in Taber stiffness units (using a length of the inventive catheter as the test strip rather than the standard dimension, homogeneous-material test strip) should be in the range of 2-400
in the range of 0.1 to 1 kg.  In the proximal shaft section (i.e., the part of the catheter proximal to the intradiscal section), this strength is in the range of 0.1 to 25 kg, preferably 0.2 to 7 kg.  In the most preferred embodiments, it is in the
range of 0.7 to 4 kg.
Returning now to FIG. 4, intradiscal section 16 is guidable and can reach the posterior, the posterior lateral, and the posterior medial regions of the posterior wall of the annulus fibrosus, as well as other selected section(s) on or adjacent to
inner wall 22.  In order to move the functional section of the catheter into a desired nucleus location, intradiscal section 16 is first positioned in the nucleus pulposus 120 by means of the introducer.
In most uses, introducer 12 pierces annulus fibrosus 122 and is advanced through the wall of the annulus fibrosus into the nucleus pulposus.  In such embodiments, introducer 12 is then extended a desired distance into nucleus pulposus 120.
Catheter 14 is advanced through a distal end of introducer 12 into nucleus pulposus 120.  Advancement of the catheter 14, combined with increased resistance to advancement at the annulus fibrosus, causes the tip of the intradiscal section to bend
relative to the longitudinal axis of introducer 12 when the intradiscal section contacts the inner wall of the annulus fibrosus 122.  Catheter 14 is navigated along inner wall 22 of annulus fibrosus 122 to selected site(s) of inner wall 22 or within
nucleus pulposus 120.  For example, intradiscal section 16 can be positioned in or adjacent to a fissure or tear 44 of annulus fibrosus 122.
The distal portion 28 of intradiscal section 16 is designed to be incapable of piercing the annulus fibrosus 122.  The inability of distal portion 28 to pierce the annulus can be the result of either shape of the tip 29 or flexibility of distal
portion 28, or both.  The tip 29 is considered sufficiently blunt when it does not penetrate the annulus fibrosus but is deflected back into the nucleus pulposus or to the side around the inner wall of the annulus when the tip 29 is advanced.  The tip
Many percutaneous and endoscopic instruments designed for other purposes can be adapted for use in this invention.  This permits other functions at the desired location after the catheter is advanced to that position.  For example, cutting edges
and sharp points can be present in the distal portion 28 if they can be temporarily masked by a covering element.  However, such devices must be sufficiently flexible and thin to meet the design characteristics described in this specification.
removed and catheter 14 is advanced through a distal end of introducer 12, following the path created by the trocar in annulus fibrosus 122 beyond the end of the introducer.  In such cases, the introducer is outside the annulus fibrosus 122 and only the
catheter with its guidable distal portion 16 is present inside the disc.  The physician can manipulate the proximal portion 15 of the catheter to move the distal portion of the catheter to a selected location for diagnosing or treating the nucleus
pulposus 120 or the inner wall 22 of the annulus fibrosus 122, such as, for example, a fissure of the annulus fibrosus 122.
spring-like material that is bent in the absence of external stress but which under selected stress conditions (for example, while the catheter is inside the introducer), is linear.  Such a biased distal portion can be manufactured from either spring
metal or superelastic memory material (such as Tinel.RTM.  nickel-titanium alloy, Raychem Corp., Menlo Park Calif.).  The introducer (at least in the case of a spring-like material for forming the catheter) is sufficiently strong to resist the bending
action of the bent tip and maintain the biased distal portion in alignment as it passes through the introducer.  Compared to unbiased catheters, a catheter with a biased distal portion 28 encourages advancement of intradiscal section 16 substantially in
the direction of the bend relative to other lateral directions as shown by the bent location of intradiscal section 16 indicated by dashed lines in FIG. 3(a).  That is, biased distal portion 28 permits advancement of intradiscal section 16 substantially
in only one lateral direction relative to the longitudinal axis of introducer 12.  More generally, embodiments of the intradiscal section may resist bending in at least one direction.  Biasing the catheter tip also further decreases likelihood that the
tip 29 will be forced through the annulus fibrosus under the pressure used to advance the catheter.
In one embodiment, the outer diameter of catheter 14 is in the range of 0.01 to 0.200 inches, the total length of catheter 14 is in the rage of 5 to 24 inches, and the length of introducer 12 is 2 to 20 inches.  The total length of catheter 14
(including the portion inside the introducer) may be in the range of 5 to 24 inches, and the length of introducer 12 may be 2 to 20 inches.  The intradiscal section may have a length at least one-half of the diameter of the nucleus pulposus.  One
embodiment of the introducer is an 18- or 17-gauge, thin-wall needle with a matched stylet.
In addition to biasing a catheter tip prior to insertion into an introducer, a catheter tip can be provided that is deflected by mechanical means, such as a wire attached to one side of the tip that deflects the tip in the desired direction upon
wire, other methods of providing a bending force at the tip can be used, such as hydraulic pressure and electromagnetic force (such as heating a shaped memory alloy to cause it to contract).  Any of a number of techniques can be used to provide selective
bending of the catheter in one lateral direction.
in the plane formed by the principal longitudinal axis of the mandrel and a line connecting the opposite sides of the shortest cross-sectional dimension of the mandrel (the &quot;thin&quot; dimension).  To provide sufficient resistance to the catheter bending out
of the desired plane while encouraging bending in the desired plane, the minimum ratio is 1.25:1 (&quot;thickest&quot; to &quot;thinnest&quot; cross-sectional dimensions along at least a portion of the intradiscal section).  The maximum ratio is 20:1, with the preferred
ratio being between 1.5:1 and 16:3, more preferably between 2:1 and 3.5:1.  These ratios are for a solid mandrel and apply to any material, as deflection under stress for uniform solids is inversely proportional to the thickness of the solid in the
direction (dimension) in which bending is taking place.  For other types of mandrels (e.g., hollow or non-uniform materials), selection of dimensions and/or materials that provide the same relative bending motions under stress are preferred.
in the examples of this specification provide a portion of the desired torsional strength.  Other materials can be substituted so long as they provide the operational functions described in the examples and desired operating parameters.
can be combined with another element, such as anti-twisting outer sheath 40 or inserting/advancing a second mandrel, to provide a catheter of the invention.  Similarly, components inside the catheter, such as a heating element or potting compound, can be
used to strengthen the catheter or provide directional flexibility at the locations of these elements along the catheter.
in size from disc to disc in one patient The bendable portion of the mandrel is preferably sufficient to allow intradiscal portion 16 of the catheter to navigate at least partially around the circumference of the inner wall of the annulus fibrosus (so
that the operational functions of the catheter can be carried out at desired location(s) along the inner wall of the annulus fibrosus).  Shorter bendable sections are acceptable for specialized instruments.  In most cases, a flattened distal portion of
The intradiscal section of the catheter can be guided to conform sufficiently to the inner wall of the annulus fibrosus to contact multiple locations of the inner wall.  The intradiscal section and/or distal portion are positionable to any
selected site around and/or adjacent to the inner wall of the annulus fibrosus for the delivery of RF energy.  The intradiscal section and/or distal portion can deliver electromagnetic energy to, e.g., heat tissue and thereby reduce pain at a selected
site (for example, any portion of the annulus fibrosus).
allow better control in the gloved hand of the physician, as in the handle 11 of FIG. 3(b)).  More complex proximal control elements capable of grasping the proximal end of the mandrel or other bending control element can be used if desired, including
but not limited to electronic, mechanical, and hydraulic controls for actuation by the physician.
The guide mandrel can also provide the function of differential flexibility by varying the thickness in one or more dimensions (for example, the &quot;thin&quot; dimension, the &quot;thick&quot; dimension, or both) along the length of the mandrel.  A guide mandrel
portions of the mandrel will resist bending at the tip but aid bending at more proximal locations.  Thickening (or thinning) can also occur in other locations along the mandrel.  Control of the direction of bending can be accomplished by making the
mandrel more round, i.e., closer to having 1:1 diameter ratios; flatter in different sections of the mandrel: or by varying the absolute dimensions (increasing or decreasing the diameter).  Such control over flexibility allows instruments to be designed
that minimize bending in some desired locations (such as the location of connector of an electrical element to avoid disruption of the connection) while encouraging bending in other locations (e.g., between sensitive functional elements).  In this
manner, a catheter that is uniformly flexible along its entire length, is variably flexibility along its entire length, or has alternating more flexible and less flexible segment(s), is readily obtained simply by manufacturing the guide mandrel with
wall/mandrel 41 that functions as the mandrel portion changes the flexibility and preferred direction of bending of the catheter.  In many cases, the wall/mandrel 41 will be thinner than other portions of the catheter wall 33 so that wall/mandrel 41
controls bending.  Alternatively, wall/mandrel 41 can be formed of a different material than the other portions 33 of the catheter walls (i.e., one with a lower tensile and/or flexural strength) in order to facilitate bending.
lumen 34 can receive any of a variety of different couplings from an energy source 20 to a thermal energy delivery device (functional element) further along the catheter, including but not limited to a wire or other connector between thermal energy
elements.  Alternatively or concurrently, hollow lumen(s) 36 for delivery and/or removal of a fluid or solid connectors for application of a force to a mechanical element can be present, so no limitation should be placed on the types of energy, force, or
material transporting elements present in the catheter.  These are merely some of the possible alternative functional elements that can be included in the intradiscal portion of the catheter.  Accordingly, a general description will now be given of some
of the possible functional elements.
To facilitate a catheter in performing some function on disc or nearby tissue, such as, for example, applying electromagnetic energy to controllably heat disc tissue at selected location(s) inside the disc, or repairing tears or fissures in a
disc by operation of the instrument at the tear location adjacent to or inside the disc, a functional element is provided in or on the catheter.  One such element is a functional electromagnetic probe such as an RF electrode.
Non-limiting examples of functional elements include any element capable of aiding diagnosis, delivering energy, or delivering or removing a material from a location adjacent the element&#39;s location in the catheter, such as an opening in the
catheter for delivery of a fluid (e.g., dissolved collagen to seal the fissure) or for suction, a thermal energy delivery device (heat source), a mechanical grasping tool for removing or depositing a solid, a cutting tool (which includes all similar
The functional element can be at varied locations in the intradiscal portion of the catheter, depending on its intended use.  Multiple functional elements can be present such as multiple functional elements of different types (e.g., a heat source
and a temperature sensor) or multiple functional elements of the same type (e.g., multiple heat sources, such as RF elements, spaced along the intradiscal portion).
One of the functional elements present on intradiscal section 16 can be an RF electrode.  A variety of different types and shapes of RF electrodes can be used.  The intradiscal section electrode can be monopolar or bipolar.  In one embodiment,
the RF electrode is positioned proximal to the distal portion of intradiscal section 16 so that there is no substantial delivery of energy at the distal portion, which can then perform other functions without being constrained by being required to
deliver RF energy.  The RF electrode is coupled to RF generating source 20 through the catheter.  The RF electrode is positioned on an external surface of intradiscal section 16.  A variety of different types of electromagnetic energy can be delivered to
tissue wherein heating is caused.  These include not only RF but also coherent and incoherent light, microwave, and ultrasound.
One of the possible functional elements present on intradiscal section 16 is a thermal energy delivery device 18.  A variety of different types of thermal energy can be delivered including but not limited to resistive heat, radiofrequency (RF),
coherent and incoherent light, microwave, ultrasound and liquid thermal jet energies.  In one embodiment, thermal energy delivery device 18 is positioned proximal to the distal portion of intradiscal section 16 so that there is no substantial delivery of
Some embodiments have an interior infusion lumen 36.  Infusion lumen 36 is configured to transport a variety of different media including but not limited to electrolytic solutions (such as normal saline), contrast media (such as Conray meglumine
iothalamate), pharmaceutical agents, disinfectants, filling or binding materials such as collagens or cements, chemonucleolytic agents and the like, from a reservoir exterior to the patient to a desired location within the interior of a disc (i.e., the
fissure).  Further, infusion lumen 36 can be used as an aspiration lumen to remove nucleus material or excess liquid or gas (naturally present, present as the result of a liquefying operation, or present because of prior introduction) from the interior
of a disc.  When used to transport a fluid for irrigation of the location within the disc where some action is taking place (such as ablation, which generates waste materials), the infusion lumen is sometimes referred to as an irrigation lumen.  Infusion
lumen 36 can be coupled to medium reservoir 21 through the catheter (see FIG. 3(a)).
Included in the particular embodiment shown in FIG. 5(a) is one or more sensor lumens 42.  An example is a wire connecting a thermal sensor at a distal portion of the catheter to control elements attached to a connector in the proximal handle 11
Also included in the embodiment shown in FIG. 5(a) is an optional energy directing device 43 including but not limited to a thermal reflector, an optical reflector, thermal insulator, or electrical insulator.  Energy directing device 43 is
configured to limit thermal and/or electromagnetic energy delivery to a selected site of the disc and to leave other sections of the disc substantially unaffected.  Energy directing device 43 can be positioned on an exterior surface of catheter
intradiscal section 16 and/or catheter 14 as well as in an internal portion of the catheter intradiscal section 16 and/or catheter 14.  For example, the energy can be directed to the walls of the fissure to cauterize granulation tissue and to shrink the
collagen component of the annulus, while the nucleus is shielded from excess heat.
In one embodiment, catheter intradiscal section 16 and/or distal portion 28 are positionable to selected site(s) around and/or adjacent to inner wall 22 of annulus fibrosus 122 for the delivery of therapeutic and/or diagnostic agents including
but not limited to, electromagnetic energy, electrolytic solutions, contrast media, pharmaceutical agents, disinfectants, collagens, cements, chemonucleolytic agents and thermal energy.  Intradiscal section 16 is navigational and can reach the posterior,
the posterior lateral, the posterior medial, anterior lateral, and anterior medial regions of the annulus fibrosus, as well as selected section(s) on or adjacent to inner wall 22.
In a preferred embodiment, intradiscal section 16 is positioned adjacent to the entire posterior wall of the disc.  Sufficient thermal energy can then be delivered, for example, to selectively heat the posterior annulus to cauterize granulation
tissue and shrink the collagen component of the wall around and adjacent to fissure 44 without undue damage to other portions of the intervertebral disc, particularly the nucleus.  These actions help close the fissure in the annulus.
marking 38 can be positioned on an exterior surface of the catheter or can be present on an interior surface and visible through a transparent outer covering or sheath.  Preferred are visible markings every centimeter to aid the physician in estimating
the catheter tip advancement.
Additionally, a radiographically opaque marking device can be included in the distal portion of the catheter (such as in the tip or at spaced locations throughout the intradiscal portion) so that advancement and positioning of the intradiscal
section can be directly observed by radiographic imaging.  Such radiographically opaque markings are preferred when the intradiscal section is not clearly visible by radiographic imaging, such as when the majority of the catheter is made of plastic
instead of metal.  A radiographically opaque marking can be any of the known (or newly discovered) materials or devices with significant opacity.  Examples include but are not limited to a steel mandrel sufficiently thick to be visible on fluoroscopy, a
tantalum/polyurethane tip, a gold-plated tip, bands of platinum, stainless steel or gold, soldered spots of gold and polymeric materials with radiographically opaque filler such as barium sulfate.  A resistive heating element or an RF electrode(s) may
provide sufficient radio-opacity in some embodiments to serve as a marking device
A sheath 40 can optionally be positioned around catheter 14.  Sheath 40 provides a flexible surface that is smooth and provides for easy introduction into a selected area within the disc.  Sheath 40 can be made of a variety of different materials
including but not limited to polyester, rayon, polyimide, polyurethane, polyethylene, polyamide and silicone.  When visible markings are present to indicate the advancement of the catheter, either the sheath carries the markings, or the sheath is clear
to reveal markings underneath.
The thermal energy delivery device can be a known RF electrode, such as a band or coil.  Heating element 46 can be an RF electrode 46 positioned on and exterior of catheter 14.  RF electrode 46 can be powered by an RF generator.  The thermal
energy delivery device can be made of a material that acts as an electrode.  Suitable materials include but are not limited to stainless steel or platinum.  The RF electrode is located on intradiscal section of catheter 14.  Increasing levels of current
conducted into the disc heats that tissue to greater temperature levels.  A circuit can be completed substantially entirely at intradiscal section 16 (bipolar devices) or by use of a second electrode attached to another portion of the body (monopolar
devices).  In either case, a controllable delivery of RF energy is achieved.
Using an RF electrode, sufficient energy can be delivered to the intervertebral disc to heat tissue positioned adjacent to catheter 14.  The amount of tissue heating is a function of (i) the amount of current passing through electrode 46, (ii)
the length, shape, and/or size of heating electrode 46, (iii) the resistive properties of the tissue, and (iv) the use of cooling fluid to control temperature.  The RF power supply 20 associated with heating electrode 46 can be battery based.  Catheter
14 can be sterilized and can be disposable.  Design of RF electrodes is within the skill of the art, and no special selection of electrode type or shape is generally required, although a particular shape or size can be selected for a particular function.
There can be two monopolar electrodes on the distal end of the RF probe.  One electrode can occupy a portion of the side of the distal end and the other can be the distal-most tip of the RF probe.  The electrodes can be operated independently to
provide different tissue temperatures.  In one configuration, the side electrode has a smaller area than the end electrode.  If the side electrode receives the same power as the end electrode, it will provide more concentrated current and thus will
produce more thermal energy.  The end electrode will provide gentler, less concentrated current and will produce less thermal energy, for example, to shrink collagen in the annulus without denaturing the collagen.
In one preferred embodiment, thermal energy delivery device 18 is a resistive heating device.  As illustrated in FIG. 6.  a heating coil 46 is positioned around an exterior of catheter 14.  The heating element 46 need not be in the shape of a
coil.  For instance, the heating element can be in the form of a thin flexible circuit which is mountable on or in substantially one side of the intradiscal portion of the catheter.  Heating element 46 is powered by a direct current source 20 (and less
preferably a source of alternating current).  Heating element is made of a material that acts as a resistor.  Suitable materials include but are not limited to stainless steel, nickel/chrome alloys, platinum, and the like.
Preferably, the heating element is inside the intradiscal section of catheter 14 (FIG. 8).  The resistive material is electrically insulated and substantially no current escapes into the body.  With increasing levels of current, element 46 heats
to greater temperature levels.  Additionally, a circuit can be completed substantially entirely at intradiscal section 16 and a controllable delivery of thermal energy is achieved.  In one embodiment, 2 watts pass through heating element 46 to produce a
temperature of about 55.degree.  C. in a selected target such as fissure 44, 3 watts produces 65.degree.  C., 4 watts produces 75.degree.  C., and so on.
In another embodiment, thermal energy delivery device 18 is a radiofrequency electrode, such as a band or coil.  As illustrated in FIG. 6, RF electrode 46 is positioned on an exterior of catheter 14.  RF electrode 46 is powered by an RF
generator.  The electrode is made of suitable materials including but not limited to stainless steel or platinum.  The RF electrode is located on intradiscal section of catheter 14.  Increasing levels of current conducted into disc tissue heat that
tissue to greater temperature levels.  A circuit can be completed substantially entirely at intradiscal section 16 (bipolar device) or by use of a second electrode attached to another portion of the patient&#39;s body (monopolar device).  In either case, a
controllable delivery of RF energy is achieved.
With a resistive heating device, the amount of thermal energy delivered to the tissue is a function of (i) the amount of current passing through heating element 46, (ii) the length, shape, and/or size of heating element 46, (iii) the resistive
properties of heating element 46, (iv) the gauge of heating element 46, and (v) the use of cooling fluid to control temperature.  All of these factors can be varied individually or in combination to provide the desired level of heat.  Power supply 20
associated with heating element 46 may he battery based.  Catheter 14 can be sterilized and may be disposable.
including but not limited to a thermistor; T type thermocouple with a copper constantan junction; J type, E type, and K type thermocouples; fiber optics; resistive wires; IR detectors; and the like.  Optionally, there may be a lumen 42 for the thermal
Referring now to the embodiment shown in FIG. 10, thermal energy delivery device 18 comprises one or more resistive heating elements 46 coupled to a resistive heating energy source.  Resistive heating elements 46 are positioned along intradiscal
section 16 at locations where they controllably deliver thermal energy to selected structures, including granulation tissue in a fissure 44 and the annulus surrounding the fissure.  Resistive heating elements 46 can be segmented and multiplexed so that
only certain resistive heating elements, or combinations of resistive heating elements are activated at any one particular time.  Thermal sensor 48 can be positioned between resistive heating elements 46 and/or at an exterior or interior location of
catheter 14.  In the embodiment illustrated in FIG. 10, catheter 14 can be prepared with a wound helical structural element 49 to increase flexibility and minimize kinking.  However, other structures and geometries are suitable for catheter 14, including
but not limited to a substantially smooth surface (and specifically including the device using an internal guide mandrel as previously described).  For example, a sheath can be provided over the heating element, and the guiding mandrel inside the coil
can be encapsulated in silicone potting material.  The tubing flexibility and the silicone potting material prevent kinking.  Additionally, sheath 40 can be positioned around catheter 14 and also around resistive heating elements 46 to afford a
substantially smooth surface.  Resistive heating element 46 can be at least partially covered by a thermally insulating material, for example, along one side of the catheter, to selectively heat disc tissue on the opposite side.
Referring now to FIGS. 11 and 12, an open or closed loop feedback system 52 couples sensors 48 to energy source 20.  As illustrated in FIG. 10, thermal energy delivery device 18 is a resistive heating element 46.  It will be appreciated that the
embodiments illustrated in FIGS. 10 and 11 are readily adaptable to other thermal energy delivery sources (e.g., for radiofrequency energy, the resistive heating element is replaced with insulated RF probe(s) and the energy source is an RF generator).
heating element 46 can be connected to separate control and power supply resources, which generate an independent output for each resistive heating element 46.  For example, a desired thermal output can be achieved by maintaining a selected energy at
resistive heating elements 46 for a selected length of time.
A control signal is generated by controller 54 that is related to the current and voltages.  The control signal is used by power circuits 66 to adjust the power output in an appropriate amount in order to maintain the desired power delivered at
maintain the desired temperature delivered at the respective sensor 48.  A multiplexer can be included to measure current, voltage, and temperature at the sensors 48, 56 and 58, so that appropriate energy can be delivered to resistive heating elements
In the embodiment shown, current sensor 56 and voltage sensor 58 are connected to the input of an analog amplifier 70.  Analog amplifier 70 can be a conventional differential amplifier circuit for use with sensors 48, 56 and 58.  The output of
analog amplifier 70 is sequentially connected by an analog multiplexer 72 to the input of A/D converter 74.  The output of analog amplifier 70 is a voltage which represents the respective sensed parameters.  Digitized amplifier output voltages are
supplied by A/D converter 74 to microprocessor 54.  Microprocessor 54 may be a type 68HCII available from Motorola.  However, it will be appreciated that any suitable microprocessor or general purpose digital or analog computer can be used to the
parameters of temperature, voltage or current.
Microprocessor 54 sequentially receives and stores digital representations of temperature.  Each digital value received by microprocessor 54 corresponds to different parameters.
Calculated power and temperature values can be indicated on user interface and display 62.  Alternatively, or in addition to the numerical indication of power, calculated power values can be compared by microprocessor 54 with power limits.  When
the values exceed predetermined power or temperature values, a warning can be given on user interface and display 62, and additionally, the delivery of electromagnetic energy can be reduced, modified or interrupted.  A control signal from microprocessor
54 can modify the power level supplied by energy source 20.
TABLE-US-00001 Tensile Geometry (height, Strength % Conductivity Resistivity Melt temp. width, and/or dia.) Component in MPa Elongation cal/cm.sup.2/cm/sec/.degree.  C. n.OMEGA.  * m .degree.  C. in mm Mandrel 600-2000 5-100 N/A N/A N/A height
0.2-2.3 width 0.05-0.5 Heating Element 300 min. 20 (min.) .025-0.2 500-1500* N/A 0.05-0.5 dia. Conductor N/A N/A .2-1.0 150 max.* N/A 0.1-0.5 dia. Wire Plastic sheath N/A 25 (min.) N/A N/A 80.degree.  (min.) 0.05-0.2 thickness
elongation can be measured according to ASTME8 (tension test of metallic materials).  Conductivity and resistivity can be determined by procedures to be found in ASTM Vol. 2.03 for electrothermal properties.
diameter of the polyimide sheath.  This heating coil provides both heat and additional stiffness to the assembly.  Also internal to the polyimide sheath on each side of the coil (longitudinally) is a 0.1 mm-walled, 304 stainless-steel, metallic band
In some embodiments, inside the bands, coil, hypodermic tube, and both the polyimide sheath and internal polyimide tube is a guiding mandrel that extends from a proximal handle to the catheter tip.  In one embodiment, this mandrel is 0.15 mm 0.5
mm and formed from 304 stainless steel.  In another embodiment, it is a 0.3 mm diameter 304 stainless steel wire, with the distal 2.5 cm flattened to 0.2 mm by 0.5 mm.
proximal end of the apparatus.  Two copper conductor wires (36 gauge-insulated with polyimide) are soldered to the heating coil and pass through the hypodermic tube and handle to the proximal handle&#39;s electrical connector, which allows a power supply and
feedback controls to be connected to electrical elements in the catheter.  One embodiment has the handle fitted with a 1-3 meter cable extension ending in an electrical connector to eliminate the need for a connector in the handle.  This design reduces
weight (from connector elements) on the proximal end and increases the physician&#39;s tactile feedback during device manipulation.
stiffness).  Instead of the silicone, another embodiment uses an epoxy which remains flexible after curing.  Strain relief is provided between the catheter body and the handle with an elastomeric boot.  The distal end of the catheter is pre-bent
The catheter in one embodiment carries visible markings 38 on the hypodermic tube (with the markings being visible through the polyimide sheath) to indicate distance of insertion of the catheter into an introducer and/or distance that the distal
end of the catheter extends out of the introducer into a disc.  The catheter is also marked both visually and with tactile relief on its handle to indicate the direction of bending of the pre-bent tip and biased stiffness.
The guidable apparatus described herein can be used in any of a number of methods to treat annular fissures.  Specific methods that can be carried out with an apparatus of the invention will now be described.
Discs with fissures can be treated non-destructively with or without the removal of nucleus tissue other than limited desiccation of the nucleus pulposus which reduces its water content.  Fissures can also be ameliorated by shrinking the collagen
component of the surrounding annulus to bring the sides closer to their normal position.  Thermal shrinkage of collagen also facilitates ingrowth of collagen which increases annular stiffness.  Fissures can also be repaired with sealants such as a filler
(non-adhesive material that blocks the opening) and/or bonding material (adhesives or cements) which help seal the tear.  The fissure can also be treated with global heating of the disc.  Most of the heat will be directed toward the fissure, but the
remainder of the disc will also receive some heat.
In some methods of the invention, bonding materials such as collagen, albumin, and a mixture of fibrinogen and thrombin are delivered to the fissure.  Collagen from a variety of sources can be used (e.g., bovine extracted collagen from Semex
Medical, Frazer Pa., or human recombinant collagen from Collagen Corp., Palo Alto, Calif.).  The collagen is injected dissolved or as a fine slurry, after which it is gradually thickens (or may be heated) in the fissure, where the injected collagen
provides a matrix for collagen disposition by the body.
A variety of different materials can also be delivered to the disc, such as, for example, to the fissure, including but not limited to electrolyte solutions (i.e. normal saline), contrast media (e.g., Conray meglumine iothalamate), pharmaceutical
agents (such as the steroid methylprednisolone sodium succinate available from Pharmacia &amp; Upjohn.  Kalamazoo, Mich., and nonsteroidal anti-inflammatory drugs), chemonucleolytic enzyme (e.g., chymopapain), hydrogel (such as disclosed in U.S.  Pat.  No.
4,478,822), osteoinductive substances (e.g., BMP, see U.S.  Pat.  No. 5,364,839), chondrocyte inductive substance (e.g., TGF-.beta.) and the like.  The materials are delivered via the catheter and/or introducer to the disc.  Preferably, however, when
precision placement of the material (as in a fissure) is necessary or desired, the delivery method uses the apparatus described above, especially when delivery to the posterior, posterior lateral, or posterior medial region of the disc is desired.  The
materials may be administered simultaneously or sequentially, such as beginning with an electrolytic solution (which helps the physician view the pathology) and following with products to seal a fissure.
The materials are delivered in an amount sufficient to decrease the extent of the fissure at least partially, preferably to fill the fissure completely.  The delivered material can be fixed in position with an adhesive, with a hydrogel that is
liquid at room temperature but gels at body temperature, with naturally occurring processes (such as interaction of fibrinogen and thrombin) within the disc, or by heating the disc as described in more detail below.
To seal a fissure, a combination of thrombin and fibrinogen is injected at the fissure, after which it coagulates and forms a seal over the fissure.  A kit with appropriate syringes and other equipment is available from Micromedics, Inc., Eagan,
Minn.  Frozen fibrinogen solution is thawed in its plastic bag and then dispensed to a small med cup.  Thrombin is reconstituted with sterile water in the &quot;slow gel&quot; concentration (100 units/ml) for tissue bonding.  For example, 100 ml is added to a vial
containing 10,000 units.  Thrombin solution is withdrawn from the vial and dispensed to a second med cup.  The two syringes are filled equally, one with each solution.  Then the syringe tips are each twisted into an applicator that mixes the solutions
before passing them to an administration tube.  The syringes are fitted into the dual syringe holder and the plunger link, which helps the practitioner administer equal amounts of thrombin and fibrinogen.  Then the practitioner connects the
administration tube to the proximal end of the inventive catheter, depresses the plungers and dispenses the sealant solution to the fissure.  The thrombin and fibrinogen react and form a natural seal over the fissure.
Chymopapain can be injected through the subject catheter, particularly near a herniation of the disc.  Chymopapain splits side chains off proteoglycan molecules, thereby decreasing their ability to hold water and their volume.  The disc gradually
loses water and decreases in size.  A typical dose is 0.75 to 1.0 ml (2000 pKat/ml).
Thermal energy is used to, e.g., cauterize granulation tissue which is pain sensitive and forms in a long-standing tear or fissure, and/or ablate granulation tissue.  Additionally or alternatively, thermal energy is used to seal at least a part
of the fissure.  To do that, the disc material adjacent to the fissure is typically heated to a temperature in the range of 45-70.degree.  C. which is sufficient to shrink and weld collagen.  In one method, tissue is heated to a temperature of at least
50.degree.  C. for times of approximately one, two, three minutes, or longer, as needed to shrink the tissue back into place.
Fissures can also be ameliorated by shrinking the collagen component of the annulus to bring the sides of the fissure closer together in their normal position, creating a smaller annular circumference.  Electromagnetic energy can be applied to
heat and shrink the collagen component of the annulus fibrosus.  This reduces the redundancy in the disc roll that is created in a degenerative disc.  This also reduces the &quot;pushing out&quot; effect that created a contained herniation.  The tightening and
stiffening of the annulus fibrosus helps the disc function more normally.  Tightening the annulus fibrosus can help stabilize the spine and relieve pain.  Careful application of electromagnetic energy locally increases the stiffness of the disc in
appropriate locations without overheating and harming other parts of the disc.
Electromagnetic energy also can be applied to shrink collagen in the nucleus pulposus.  Delivery of electromagnetic energy to the nucleus pulposus removes some water and permits the nucleus pulposus to withdraw.  This also can reduce the &quot;pushing
out&quot; effect.  Shrinking the disc, such as, for example, by shrinking of the nucleus pulposus by reducing water content, and/or tightening up the annulus fibrosus wall can create a rejuvenation of the disc.  Reducing the pressure in the disc and
tightening the annulus fibrosus can produce a favorable biomechanical effect.
The energy delivery device can be configured to deliver sufficient energy to the intervertebral disc to provide a denervation of a nerve at a selected site of the intervertebral disc.  For example, degenerative intervertebral discs with fissures
can be treated by denervating selected nerves that are, for example, imbedded in the interior wall of the annulus fibrosus or that are located outside of the interior wall including those on the surface of the wall.  Electromagnetic energy can be used to
cauterize granulation tissue which is a pain sensitive area and formed in the annulus fibrosus wall.  Sufficient thermal energy also can be delivered to selectively denervate nociceptors in and adjacent to, for example, a fissure.
The foregoing description of preferred embodiments of the invention has been presented for purposes of illustration and description.  It is not intended to be exhaustive or to limit the invention to the precise forms disclosed.  Many
A number of embodiments have been described.  Nevertheless, it will be understood that various modifications may be made.  Accordingly, other embodiments are within the scope of the following claims.
Method and apparatus for treating annular fissures in intervertebral discs, Sharkey, et al., Hugh R. Sharkey, John Ashley, Joel Saal, Jeffrey A. Saal, Le Trong Le, Application number 10 388-609, Surgery: LightThermal And Electrical Application, Surgery, intervertebral disc, nucleus pulposus, Intervertebral Discs, annulus fibrosus, inner wall, heating element, control apparatus, distal portion, catheter tip, Patent number
This document relates to methods and apparatuses for modifying intervertebral disc tissue and more particularly to the treatment of annular fissures and other conditions using percutaneous techniques to avoid major surgical intervention.Intervertebral disc abnormalities have a high incidence in the population and may result in pain and discomfort if they impinge on or irritate nerves. Disc abnormalities may be the result of trauma, repetitive use, metabolic disorders and theaging process and include such disorders but are not limited to degenerative discs (i) localized tears or fissures in the annulus fibrosus, (ii) localized disc herniations with contained or escaped extrusions, and (iii) chronic, circumferential bulgingdisc.Disc fissures occur rather easily after structural degeneration (a part of the aging process that may be accelerated by trauma) of fibrous components of the annulus fibrosus. Sneezing, bending or just attrition can tear these degenerated annulusfibers, creating a fissure. The fissure may or may not be accompanied by extrusion of nucleus pulposus material into or beyond the annulus fibrosus. The fissure itself may be the sole morphological change, above and beyond generalized degenerativechanges in the connective tissue of the disc. Even if there is no visible extrusion, biochemicals within the disc may still irritate surrounding structures. Disc fissures can be debilitatingly painful. Initial treatment is symptomatic, including bedrest, pain killers and muscle relaxants. More recently spinal fusion with cages have been performed when conservative treatment did not relieve the pain. The fissure may also be associated with a herniation of that portion of the annulus.With a contained disc herniation, there are no free nucleus fragments in the spinal canal. Nevertheless, even a contained disc herniation is problematic because the outward protrusion can press on the spinal nerves or irritate other structures. In addition to nerve root comp