U.S. patent application number 14/675626 was filed with the patent office on 2015-07-23 for methods and apparatus for accessing and treating the facet joint.
The applicant listed for this patent is PROVIDENCE MEDICAL TECHNOLOGY, INC.. Invention is credited to Nathan Christopher Maier, Bruce M. McCORMACK.
Application Number | 20150201977 14/675626 |
Document ID | / |
Family ID | 40470002 |
Filed Date | 2015-07-23 |
United States Patent
Application |
20150201977 |
Kind Code |
A1 |
McCORMACK; Bruce M. ; et
al. |
July 23, 2015 |
METHODS AND APPARATUS FOR ACCESSING AND TREATING THE FACET
JOINT
Abstract
Methods and systems are disclosed for accessing and treating the
interior of the facet joint for vertebral distraction and
immobilization. The systems include a number of tools that
facilitate access to the facet joint, distraction of the
articulating decortication of the articulating surfaces, and
delivery of implants and agents into the facet joint for
fusion.
Inventors: |
McCORMACK; Bruce M.; (San
Francisco, CA) ; Maier; Nathan Christopher; (Hayward,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PROVIDENCE MEDICAL TECHNOLOGY, INC. |
LAFAYETTE |
CA |
US |
|
|
Family ID: |
40470002 |
Appl. No.: |
14/675626 |
Filed: |
March 31, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12350609 |
Jan 8, 2009 |
9005288 |
|
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14675626 |
|
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|
61020082 |
Jan 9, 2008 |
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Current U.S.
Class: |
606/84 |
Current CPC
Class: |
A61F 2/4601 20130101;
A61F 2/4455 20130101; A61F 2310/00359 20130101; A61F 2002/30616
20130101; A61B 17/3211 20130101; A61B 17/1659 20130101; A61B
17/1604 20130101; A61B 17/7074 20130101; A61B 17/1671 20130101;
A61F 2/4611 20130101; A61B 17/00234 20130101; A61F 2/441 20130101;
A61F 2/28 20130101; A61B 2017/0256 20130101; A61F 2/4405
20130101 |
International
Class: |
A61B 17/70 20060101
A61B017/70; A61B 17/3211 20060101 A61B017/3211; A61B 17/00 20060101
A61B017/00 |
Claims
1. An apparatus for minimally invasively accessing an interior
region of a facet joint, the facet joint comprising first and
second articulating subchondral surfaces defining first and second
boundaries of a facet cavity, the facet joint further comprising a
facet capsule defining a third boundary of the facet cavity, the
apparatus comprising: an elongate handle having a proximal end and
a distal end; and a blade disposed at the distal end of the handle,
the blade comprising a flat leading edge and configured so that
placement of the blade through the facet capsule and into the facet
cavity generates a slit-shaped aperture in the facet capsule, the
slit-shaped aperture extending substantially parallel to the first
and second articulating subchondral surfaces, the blade and distal
end configured to be passable through a minimally invasive route
leading to the facet capsule.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation application of Ser. No.
12/350,609, filed Jan. 8, 2009, entitled "METHODS AND APPARATUS FOR
ACCESSING AND TREATING THE FACET JOINT," which claims priority to
U.S. Provisional Patent Application No. 61/020,082, entitled
"METHODS AND APPARATUS FOR ACCESSING AND TREATING THE FACET JOINT,"
filed on Jan. 9, 2008. The full disclosures of the above-listed
patent applications are hereby incorporated by reference
herein.
FIELD
[0002] This invention pertains generally to treatment of the facet
joint, and more particularly to tools and methods for accessing,
preparing and facilitating spinal distraction.
BACKGROUND
[0003] Neck and arm pain is a common ailment of the aging spine due
to disc herniations, facet arthropathy and thickening of spinal
ligaments which narrow spinal canal dimensions. This results in
compression of the spinal cord or nerve roots, or both. Radicular
pain is typically due to disc herniation and foraminal narrowing,
which compresses the cervical nerve roots and causes radicular
pain. Extension and ipsilateral rotation of the neck further
reduces the foraminal area and contributes to pain, nerve root
compression, and neural injury. Neck flexion generally increases
the foraminal area.
[0004] Cervical disc herniations and foraminal stenosis typically
present with upper extremity radicular pain without major motor or
sensory neurologic deficit. A well-described treatment for cervical
disc herniations is closed traction. There are a number of marketed
devices that alleviate pain by pulling on the head to increase
foraminal height.
[0005] Cervical disc herniations have been treated with anterior
and posterior surgery. The vast majority are performed through an
anterior surgical approach, which entails a spinal fusion. These
surgeries are expensive and beget additional surgeries due to
change in biomechanics of the neck. There is a 3% incidence of
re-operation per year that is cumulative at adjacent levels.
[0006] There is a need in the art for minimally invasive methods
and devices for accessing and preparing and distracting the facet
joint to increase foraminal height and reduce radicular symptoms
for patients with soft and hard disc disease.
BRIEF SUMMARY
[0007] Devices and techniques are disclosed for a percutaneous or
minimally invasive surgical implantation to reduce radicular
symptoms by inserting an expandable cervical distraction implant in
the facet joint at a symptomatic level to decompress the nerve
tissue and preserve motion. In particular, embodiments of the
present invention provide for accessing and distracting the
cervical facet to increase the foraminal dimension. In one
embodiment, the implant of the present invention, when positioned
in the cervical facet joint, increases the space between the
articular facets, to increase the foraminal area or dimension, and
reduce pressure on the nerve and associated blood vessels.
[0008] The procedure may be performed under conscious sedation in
order to obtain intra-operative patient symptom feedback.
[0009] An aspect of an embodiment of the invention is an apparatus
for accessing an interior region of a facet joint, comprising an
elongate handle having a proximal end and a distal end, and a blade
disposed at the distal end of the handle. The blade may have a flat
leading edge such that placement of the blade through the facet
capsule and into the facet cavity to generate a slit-shaped
aperture in the facet capsule. Preferably, the aperture may extend
substantially parallel to the first and second articulating
subchondral surfaces.
[0010] In one embodiment, the blade comprises a planar lower
surface extending from the leading edge, and extending proximally
away from the leading edge, wherein the planar surface provides a
platform to guide a second instrument through the aperture for
treatment of the facet joint.
[0011] In one mode of the current embodiment, the blade comprises
an upper surface opposite the lower surface, with the upper surface
and lower surface defining a thickness, generally sized to be
smaller than the distance between the first and second boundaries
of a facet cavity.
[0012] Preferably, in one embodiment, a beveled surface emanates
from the upper blade surface and extends proximally away from the
leading edge. Accordingly, the thickness increases proximally along
the beveled surface. The beveled surface generally facilitates
manipulation of the blade into the cavity.
[0013] In one embodiment, the handle comprises a shaft extending
from the distal end to the proximal end, wherein the shaft
comprises a beveled surface emanating at or near the leading edge
and extending proximally away from the leading edge. The beveled
surface facilitates insertion of the blade into the cavity at an
angle not aligned with the first and second cavity boundaries.
[0014] In another embodiment, the shaft is disposed within a
central channel running along the length of the handle, and extends
from the distal end of the handle. The shaft may have a D-shaped
cross section providing a flat planar surface in cooperation with
the blade.
[0015] Another aspect of an embodiment is an apparatus for
decorticating an interior region of a facet joint, comprising an
elongate handle having a proximal end and a distal end, and a rasp
configured to decorticate a at least one of the articulating
subchondral surfaces. The rasp may have a roughened planar surface
extending distally outward from the distal end of the handle, and
may be generally spatula-shaped and sized to be delivered into the
facet joint via an aperture in the joint capsule and oriented in
the joint substantially in line with the plane of the facet joint
articulating surfaces. Generally the rasp comprises a compliant,
thin cross section that allows the rasp to bend while being
delivered into the facet from an angle out of alignment with the
plane of the facet joint articulating surfaces.
[0016] The blade may have substantially planar lower surface
extending from the leading edge, and extend proximally away from
the leading edge. This planar surface may provide a platform for
guiding the rasp in cooperation with a second instrument through
the aperture for treatment of the facet joint.
[0017] In another embodiment, the rasp comprises an upper roughened
surface opposite and substantially parallel with the lower surface,
wherein the thickness is sized to be smaller than the distance
between the first and second boundaries of a facet cavity, and to
dispose the rasp to bending under light to moderate pressure. A
beveled surface may emanate from the upper surface at a point
proximal from a leading edge of the rasp and extending proximally
away from the leading edge.
[0018] Another aspect of an embodiment is an apparatus for
accessing an interior region of a facet joint, comprising an
elongate handle having a proximal end and a distal end, and a
spatula-shaped tip disposed at the distal end of the handle, with
the tip comprising upper and lower parallel planar surface
extending distally outward from the distal end of the handle. The
tip may be sized to be delivered into the facet joint via an
aperture in the joint capsule and oriented in the joint
substantially in line with the plane of the facet joint
articulating surfaces.
[0019] In one embodiment, the upper and lower parallel planar
surfaces define a thickness that allows the tip to bend while being
delivered into the facet from an angle out of alignment with the
plane of the facet joint articulating surfaces.
[0020] In another embodiment, lower planar surface provides a
platform for guiding a second instrument through the aperture for
treatment of the facet joint.
[0021] The thickness may be generally sized to be smaller than the
distance between the first and second boundaries of a facet cavity,
and to dispose the tip to bending under light to moderate pressure.
The apparatus may have a beveled surface emanating from the upper
surface at a point proximal from a leading edge of the tip and
extending proximally away from the leading edge.
[0022] In one embodiment, the handle comprises a shaft extending
from the distal end to the proximal end, the shaft having a beveled
surface emanating from the upper surface and terminating at a
proximal location toward the handle. The lower planar surface may
extend beyond the proximal location to create a platform for
guiding a second instrument to the aperture and introducing the
second instrument into the cavity.
[0023] The second instrument may comprise a rasp configured to
decorticate at least one of the articulating surfaces, a distracter
for distracting the articulating surfaces, an injector for
delivering an agent into the cavity, or an introducer for
delivering an implant into the cavity. The tip may function as a
platform configured to receive an expandable implant and deliver
the implant to a location within the cavity.
[0024] Another aspect of an embodiment is an apparatus for
distracting two adjacent vertebrae, the being vertebrae separated
by a facet joint comprising first and second articulating
subchondral surfaces forming a facet cavity enclosed by a facet
capsule. The apparatus may include an elongate handle having a
proximal end and a distal end; and a wedge detachably disposed at
the distal end of the handle. The wedge may have upper and lower
beveled surfaces that converge toward a distal tip of the wedge,
and is sized to be delivered into the cavity through an aperture in
the capsule so that the upper and lower beveled surfaces contact
the first and second articulating subchondral surfaces and distract
the surfaces as the wedge is driven into the cavity.
[0025] In one embodiment, the wedge may comprise a recess on a
proximal end of the wedge for detachably coupling the wedge to the
handle.
[0026] In another embodiment, the apparatus may further include a
shaft extending from the distal end of the handle proximal to the
wedge. The wedge may be detachably coupled to the shaft. In one
embodiment, the shaft may have a planar surface leading from the
handle to the wedge to provide a platform for guiding the wedge in
cooperation with a second instrument through the aperture.
[0027] Generally, the upper and lower beveled surfaces extend
proximally from the distal tip to parallel upper and lower
distraction surfaces, wherein the distraction surfaces are
distanced from each other by a distraction thickness. The
distraction thickness may correlate to a desired distraction of the
articulating surfaces of the facet joint.
[0028] In another embodiment, wherein the wedge comprises one of a
plurality of detachable wedges, with each of the detachable wedges
having an increasingly larger distraction thickness such that the
plurality of detachable wedges may be delivered to the facet joint
in series from thinnest to thickest to incrementally distract the
facet joint.
[0029] In a preferred embodiment, the upper and lower beveled
surfaces converge to a nipple located at the distal end of the
wedge, wherein the nipple is sized to be inserted in the cavity
between the articulating surfaces.
[0030] Another aspect of an embodiment is an apparatus for
distracting two adjacent vertebrae, having an elongate handle with
a proximal end and a distal end, and upper and lower reciprocating
members disposed at the distal end of the handle. The upper and
lower reciprocating members may be coupled to the handle via a
hinge located between proximal and distal ends of the upper and
lower reciprocating members. The distal ends of the upper and lower
reciprocating members may extend past the distal end of the handle
such that the distal ends of the upper and lower reciprocating
members may be pressed together to create a smaller profile for
entry into the facet capsule and in between the first and second
articulating subchondral surfaces. The entry into the facet capsule
may result in extension of the proximal ends of the upper and lower
reciprocating members away from the handle, wherein the proximal
ends of the upper and lower reciprocating members are configured be
articulated toward the handle, the hinge acting as a fulcrum to
separate the distal ends of the upper and lower reciprocating
members and distract the first and second articulating subchondral
surfaces.
[0031] Generally, the distal ends of the upper and lower
reciprocating members may be sized to be delivered into the facet
cavity through an aperture in the facet capsule.
[0032] In one embodiment, the handle may comprise a hollow tube,
with a shaft running through the tube to the distal end of the
handle, and a rasp coupled to the shaft at the distal end of the
handle, wherein the shaft may be reciprocated within the tube such
that the rasp runs along a subchondral surface to decorticate the
surface.
[0033] Another aspect of an embodiment is an introducer for
delivering an implant to an interior region of a facet joint,
comprising an elongate handle having a proximal end and a distal
end, and a spatula-shaped tip disposed at the distal end of the
handle, the tip comprising upper and lower parallel planar surface
extending distally outward from the distal end of the handle. The
tip may be sized to be delivered into the facet joint via an
aperture in the joint capsule and oriented in the joint
substantially in line with the plane of the facet joint
articulating surfaces, and comprises a platform configured to
receive the implant and deliver the implant to a location within
the cavity.
[0034] In one embodiment, the implant may comprise an inflatable
membrane with a pocket configured to slide over the distal tip of
the introducer. In this case, the introducer has a delivery line
extending from the proximal end of the handle to distal tip and
being configured to dispense an inflation medium to the inflatable
membrane.
[0035] Another aspect of an embodiment is an apparatus for
delivering an agent to an interior region of a facet joint, having
an elongate handle with a proximal end and a distal end, and a
shaft extending from the distal end of the handle. The shaft has a
beveled surface at its distal tip, and a delivery line extending
from the proximal end of the handle to the distal tip of the shaft.
The beveled distal tip of the shaft may be sized to be delivered
into the facet joint via an aperture in the joint capsule and
oriented in the joint to deliver the agent to a treatment location
within the joint. A blade may also be included on the distal end of
the shaft, the blade configured to facilitate access into the facet
joint.
[0036] In one embodiment of the current aspect, the shaft may
comprise a lower planar surface extending proximally from the
distal tip, wherein the lower planar surface provides a platform
for guiding the apparatus in cooperation with a second instrument
through the aperture.
[0037] Another aspect of an embodiment is a surgical system for
treating the facet joint, comprising a first apparatus configured
to gain access to the joint. The first apparatus may have an
elongate handle having a proximal end and a distal end, and
spatula-shaped tip disposed at the distal end of the handle, the
tip comprising upper and lower parallel planar surface extending
distally outward from the distal end of the handle. The tip may be
sized to be delivered into the facet joint via an aperture in the
joint capsule and oriented in the joint substantially in line with
the plane of the facet joint articulating surfaces. The lower
planar surface may provide a platform for guiding a second
instrument through the aperture for treatment of the facet joint.
The second instrument may comprise a planar surface that is
configured to mate with the planar surface of the first instrument
and slide distally along the first instrument to into the facet
joint.
[0038] Another aspect of an embodiment is a system for facet joint
immobilization, comprising: a facet access blade configured to
pierce through the facet capsule and into the facet cavity to
generate a slit-shaped aperture in the facet capsule that extends
substantially parallel to the first and second articulating
subchondral surfaces. The system may include a distraction
apparatus configured to be delivered through the facet capsule and
into the facet cavity to distract the first and second articulating
subchondral surfaces a predetermined distance, and a decortication
apparatus configured to be delivered through the facet capsule and
into the facet cavity to decorticate at least one of the first and
second articulating subchondral surfaces a predetermined distance.
An introducer may also be delivered through the facet capsule and
into the facet cavity to deliver an implant between the first and
second articulating subchondral surfaces to immobilize the joint at
the predetermined distance.
[0039] Another aspect of an embodiment is a method for accessing
the facet joint of a patient, comprising: delivering a cutting
blade to the facet joint capsule; and piercing through the facet
capsule and into the facet cavity with the cutting blade to
generate a slit-shaped aperture in the facet capsule, the aperture
being oriented and sized to accommodate access into the facet
joint
[0040] The method may further include delivering an introducer
through the aperture and into the facet cavity. The cutting blade
may be configured to guide delivery of the introducer.
[0041] Another aspect of an embodiment is a method for accessing
the facet joint of a patient, comprising: delivering a first
apparatus configured to gain access to the joint. The first
apparatus comprising an elongate handle having a proximal end and a
distal end, and a spatula-shaped tip disposed at the distal end of
the handle, the tip comprising upper and lower parallel planar
surface extending distally outward from the distal end of the
handle. The tip is sized to be delivered into the facet joint via
an aperture in the joint capsule and oriented in the joint
substantially in line with the plane of the facet joint
articulating surfaces. A second apparatus is delivered by guiding
the second apparatus along the lower planar surface of the first
apparatus and through the aperture for treatment of the facet
joint. The second apparatus may have a planar surface that is
configured to mate with the planar surface of the first apparatus
and slide distally along the first apparatus to into the facet
joint.
[0042] Yet another aspect of an embodiment is a method for
immobilizing the facet joint of a patient; comprising delivering a
cutting blade to the facet joint capsule; piercing through the
facet capsule and into the facet cavity with the cutting blade to
generate an aperture in the facet capsule accessing the joint with
an introducer; preparing the joint by sanding down cortical bone
with a rasp; wherein the rasp is configured to be non-invasively
inserted within the aperture created by the cutter; and delivering
a distraction device into the facet cavity and distracting the
first and second articulating subchondral surfaces.
[0043] In one embodiment, the introducer facilitates delivery of
the rasp and distraction device.
[0044] In one embodiment, the distraction device comprises a wedge
detachably disposed at the distal end of an elongate handle, with
the method further including delivering the wedge into the cavity
through an aperture in the capsule so that the wedge contacts the
first and second articulating subchondral surfaces and distract the
surfaces as the wedge is driven into the cavity.
[0045] In another embodiment, the distraction device comprises an
inflatable membrane, and distracting the first and second
articulating subchondral surfaces comprises inflating the
membrane.
[0046] In yet another embodiment, the distraction device comprises
a reciprocating introducer, and distracting the first and second
articulating subchondral surfaces comprises inserting the
introducer into the facet joint and articulating a pair of distal
reciprocating members.
[0047] Further aspects of the invention will be brought out in the
following portions of the specification, wherein the detailed
description is for the purpose of fully disclosing preferred
embodiments of the invention without placing limitations
thereon.
BRIEF DESCRIPTION OF DRAWINGS
[0048] The invention will be more fully understood by reference to
the following drawings which are for illustrative purposes
only:
[0049] FIG. 1 is a lateral view of two cervical vertebral members
in a stenosed condition.
[0050] FIG. 2 is a view of a traditional introducer needle being
inserted into the facet joint of the vertebral members.
[0051] FIGS. 3A-3H include several views of a facet access tool
according to certain embodiments.
[0052] FIG. 4 is a schematic lateral view of the facet access tool
of FIGS. 3A-3H positioned at the facet joint capsule of two
cervical vertebral members.
[0053] FIG. 5 is a schematic lateral view of the facet access tool
of FIGS. 3A-3H piercing and being manipulated within the facet
joint capsule, according to certain embodiments.
[0054] FIG. 6 is another view of the of the facet access tool of
FIGS. 3A-3H piercing the facet joint capsule, according to certain
embodiments.
[0055] FIG. 7 is a view of the slit-shaped aperture created by the
facet access tool of FIGS. 3A-3H.
[0056] FIGS. 8A-8H include several views of a facet introducer,
according to certain embodiments.
[0057] FIG. 9 is a schematic lateral view of the introducer tool of
FIGS. 8A-8H being manipulated within the facet joint capsule,
according to certain embodiments.
[0058] FIG. 10 is a schematic lateral view of the facet blade being
used to guide the introducer tool of FIGS. 8A-8H into the joint
capsule, according to certain embodiments.
[0059] FIGS. 11A-11I include several views of a facet distraction
device, according to certain embodiments.
[0060] FIGS. 12A-H include several views of a detachable wedge used
with the facet distraction device of FIGS. 11A-11I.
[0061] FIGS. 13A-13G include several views of an alternative facet
distraction device, according to certain embodiments.
[0062] FIGS. 14A-14I include several views of a facet decortication
tool, according to certain embodiments.
[0063] FIGS. 15A-15G include several views of a facet delivery tool
for delivering an injectable biomaterial, according to certain
embodiments.
[0064] FIGS. 16A-16I include several views of a facet inflatable
membrane introducer, according to certain embodiments.
DETAILED DESCRIPTION
[0065] Referring more specifically to the drawings, for
illustrative purposes, one embodiment of an apparatus is generally
shown in FIG. 3A through FIG. 16. It will be appreciated that the
apparatus may vary as to configuration and as to details of the
parts, and that the method may vary as to the specific steps and
sequence, without departing from the basic concepts as disclosed
herein.
[0066] FIG. 1 illustrates a simplified lateral view of a portion of
the cervical spine 10. The basic biomechanical unit or motion
segment of the spine consists of two adjacent vertebrae 12 and 14
and the three joint articular complex through which they move and
are constrained in relation to one another. The spine articulations
generally consist of an intervertebral disc 26 located between the
vertebral bodies 26 of adjacent vertebrae 12, 14, and two facet
joints 16 symmetrically located laterally from the sagittal plane
at the posterior end of the vertebral bodies 26.
[0067] The facet joints 16 allow constrained spinal motion, while
protecting the contained neural structures. From a kinematic
viewpoint, the intervertebral facet joints 16 are highly
constrained sliding planar articulations, lubricated by synovial
fluid contained within the facet joint capsule 30. In the cervical
spine, the geometry of the cervical vertebral bodies provides a
high degree of protection for the neural elements by limiting
normal motion of the spine to within physiologic limits. The upward
inclination of the superior articular surfaces of the facet joints
allows for considerable flexion and extension, as well as for
lateral mobility.
[0068] The distraction, preparation and delivery devices disclosed
herein facilitate minimally invasive or percutaneous surgical
access, distraction and implant delivery to the facet joint, which
is advantageous due to reduced surgical time, reduced recovery
time, and improved surgical outcome. Each vertebral segment
comprises a spinous process 34 located at the posterior end of the
vertebrae, with the vertebral body located anteriorly. Each
vertebra comprises an inferior articular (or transverse) process 35
and the superior articular process 37 that form four posterior
articulating, e.g. opposing subchondral, surfaces: two superior
facets 18 and two inferior facets 16. The inferior facet 18 from
the inferior articular process 35 of the upper vertebra 12 and the
superior facet from the superior articular process 37 of the lower
vertebra 14 form the facet joint 16 on each lateral side of the
spine.
[0069] Located medial to the articular processes 37 and vertebral
bodies 26 is an aperture, or intervertebral foramina 38, that
serves as a nerve root canal for the spinal nerves and vessels that
transmit signals from the spinal chord to respective locations in
the body.
[0070] Each facet joint 16 is covered by a dense, elastic articular
capsule 28, which is attached just beyond the margins of the
articular facets 18, 22. The inside of the capsule is lined by a
synovial membrane (not shown), which secretes synovial fluid for
lubricating the facet joint. The exterior of the joint capsule is
surrounded by a capsular ligament (not shown), which may be
temporarily repositioned to give access for insertion of the
extendable implant of the present invention, described in further
detail below. Thus, from a posterior-lateral approach, access to
the facet joint 16 is relatively straightforward and well
prescribed, as compared to other regions of the spine, which
present a higher likelihood of trauma and risk of permanent
damage.
[0071] It should also be noted that FIG. 1 depicts cervical
foraminal stenosis, e.g. loss of height between the adjacent
vertebrae 12, 14. As a result of disc 36 herniation and
corresponding height loss, the nerve root canal 38, or
intervertebral foraminal height, having a value H.sub.s, is
narrowed relative to that of healthy anatomy. This narrowing of the
foraminal height H.sub.s often leads to compression of the spinal
cord and nerve roots (not shown), causing radicular symptoms.
[0072] As a result of the stenosed foraminal height H.sub.s, the
height of the facet joint 16, or distance between subchondral
articulating surfaces 18 and 22, is also narrowed, (shown as value
D.sub.s in FIG. 1). This may pose complications in the facet joint
16 as well. However, because the height of the disc will be
relatively fixed, an increase in the facet joint height will also
have a corresponding increase in foraminal height, as described in
greater detail below.
[0073] FIG. 2 illustrates a typical procedure for accessing the
facet joint using a standard discography introducer needle 44 to
access the facet joint. Because the gap or cavity 30 bound between
subchondral articulating surfaces 18 and 22 is generally planar,
the cylindrical needle 44 may be difficult to navigate into the
capsule 30. Generally precise alignment and orientation of the
needle 44 with the subchondral surface 18 and 22 may be used for
the needle to enter the cavity 30. Thus, the shape and size
constraints of the facet joint 16 make typical cylindrical needles
44 difficult to predictably and consistently gain access to the
facet joint capsule.
[0074] FIGS. 3A-16 show a system and method of the present
invention for performing a minimally invasive procedure configured
to distract one or more of the facet joints 16 of vertebrae 12, 14,
thereby increasing the dimension of the neural foramen while
retaining facet joint mobility. One of the major advantages of
minimally invasive surgery is the ability to perform the procedure
with minimal tissue trauma. Television image intensifier
fluoroscopy may be used to provide guidance for surgeon placement
of instrumentation and implants precisely to the desired anatomic
target in the facet joint 16. The radiographic landmarks are well
taught and the relative procedural difficulty of this technique is
low.
[0075] FIGS. 3A-3H illustrate a facet access tool 100 in accordance
with certain embodiments. Tool 100 comprises an elongate handle
having a flat cutting blade 112 on its distal end 102. The blade
112 generally comprises a straight, flat (i.e. planar), leading
edge 110 at distal tip 102 that is sharpened to allow for piercing
of the facet joint capsule 28. Although the leading edge 110 is
shown as a straight-line surface when viewed from above in FIG. 3B,
it is appreciated that different shapes may also be utilized, (e.g.
arcuate, triangular, etc.)
[0076] The blade 110 is coupled to shaft 108 that is received
inside a central channel 116 running axially down handle 106. The
shaft and blade protrude distally from the handle 106 so that flat
surface 114 running along the bottom of the blade 112 is exposed.
The flat surface 114 facilitates introduction and cooperation of
additional instruments used for the procedure, discussed in further
detail below.
[0077] The shaft 108 has a beveled surface 118 that terminates at a
point on the distal tip 102 of blade 112. As will be described in
further detail below, the beveled surface 118 allows the blade 112
to access into the facet joint from sub-optimal angles of entry,
and wedge the blade 112 into the joint for treatment.
[0078] It is appreciated that blade 112 may be a separable from
shaft 108 and joined with an adhesive, fastener or other securing
means. Alternatively blade 112 and shaft 108 may comprise one
contiguous or integral piece of material. The blade and shaft may
comprise a hardened metal, such as stainless steel or titanium.
[0079] The blade 112 and shaft 108 correspondingly have a D-shaped
cross-section. Accordingly, chamber 116 of handle 106 also has a
D-shaped cross-section, and is sized to receive shaft 108 and blade
112 with a snug fit. Handle 106 may comprise a plastic or similar
polymer that is extruded, molded, or heat-shrunk in shape.
[0080] FIG. 4 illustrates lateral views of facet access tool 100
positioned at the facet joint 16. According to the method of the
present invention, the blade 112 is positioned at the desired
location facet joint capsule 28 and then pushed into the capsule to
generate an opening 32. FIG. 5 shows the access tool 100
manipulated in the facet cavity 30 through the opening 32 in the
capsule wall 28.
[0081] FIGS. 6 and 7 illustrate a postero-lateral view of the
incision created by the access tool. As seen in FIG. 7 a slit-like
opening 32 is generated that runs generally parallel to the facet
joint articular surfaces 18, 22.
[0082] Once we have gained access to the facet joint cavity 30 with
the cutting blade of the facet access tool 100, an introducer 150
may be inserted into the joint. The introducer 150, illustrated in
FIG. 8, comprises a handle 164 at its proximal end, and a malleable
"spatula" shaped tip 154 at its distal end 152.
[0083] The tip 154 generally comprises a straight, flat leading
edge 110 at distal end 152. Although the leading edge 152 is shown
as a straight-line surface when viewed from above in FIG. 8A, it is
appreciated that different shapes may also be utilized, (e.g.
arcuate, triangular, etc.)
[0084] The tip 254 is coupled to shaft 158 that is received within
a D-shaped opening channel 168 of the handle 156. The shaft 158 and
tip 154 protrude distally from the handle 156 so that flat surface
160 running along the bottom of the tip and shaft is exposed. The
shaft 158 has a beveled surface 162 that terminates at a point
proximal to the distal tip end 152 of tip 154.
[0085] The malleable and thin planar shape of the "spatula" tip 154
and beveled shaft 158 allow for suboptimal entry angles and
compensates for the narrow spacing of the facet joint. In the
method of the present invention, the tip 154 is inserted into the
opening 32 created by the facet access tool 100. The flat, thin
cross-section of tip 154 is configured to easily slide into thin,
planar cavity 30 of the facet joint 30.
[0086] As shown in FIG. 9, the tip 154 of introducer is malleable
so that it bends into the cavity 30 if introduced from a sub
optimal angle. This, along with the beveled surface 162, allows the
blade introducer 150 to access into the facet joint from
sub-optimal angles of entry, and wedge or manipulate the introducer
150 into the proper orientation in the joint 16 for treatment.
[0087] The introducer 150 may be inserted into the cavity 30 after
the access blade 100 has been removed, or may be inserted while the
access blade 100 is still in place, essentially using the access
blade to guide the introducer 150 by sliding the flat bottom
surface 160 along the bottom surface 114 of the access blade, as
shown in FIG. 10.
[0088] In a similar fashion as illustrated in FIG. 10 with the
access blade 100, the flat tip 154 of the introducer is also
configured to provide a point of entry for later devices used in
the surgical method of the present invention, e.g. to enable
distraction, decortication, decompression, and fusion of the facet
joint 16.
[0089] With proper access and orientation of the instruments in the
facet joint 16, the articular surfaces 18 and 22 may be distracted
to increase the distance D.sub.s. Distraction of the joint 16 may
be accomplished via a number of methods, including use of an
inflatable membrane such as that disclosed in U.S. patent
application Ser. No. 11/618,619 filed on Dec. 29 2006, herein
incorporated by reference in its entirety.
[0090] Referring now to FIGS. 11A-11I and 12A-12H, distraction may
be achieved via a wedge-inserter 170. The wedge inserter 170
comprises an elongate handle 178 at its proximal end 180 and
detachable wedge-shaped tip 172 disposed on shaft 174 that is
encased, at least proximally, within the handle 178.
[0091] The detachable tip 172, further illustrated in FIGS.
12A-12H, converges to a nipple 176 at the distal extremity via
beveled surfaces 182 and lateral arcuate surfaces 184. The
detachable tip 172 has a keyed receiving hole 186 for attaching the
tip 172 to the shaft 174.
[0092] The upper and lower beveled surfaces 182 converge to nipple
176 from a box shaped platform defined by lower and upper parallel
distraction surfaces 188, and 190. The distance between the lower
and upper distraction surfaces 188, and 190 sets the thickness T of
the wedge.
[0093] The inserter 170 may be directed into to the facet joint
cavity 30 with guidance from sliding it along introducer 150. When
inserted into the cavity 30, the inserter generates an outward
compressive force on the subchondral surfaces 18 and 22 to increase
the distance between them to a desired treatment or nominal value
D.sub.T. As shown in FIGS. 12B-12D, a set of tips 192, 194 and 196,
all having a different thickness T, may be used in series so that
the joint is progressively distracted. The final thickness T will
correspond to the treatment or nominal value D.sub.T.
[0094] This distraction of walls 18 and 22 correspondingly
increases the height of the intervertebral foramin to a treatment
or nominal value H.sub.T. The value of D.sub.T, and resulting
increase in H.sub.T may be predetermined by the surgeon prior to
the surgery based on pre-op analysis of the patient's condition and
anatomy, and/or may also be iteratively devised by patient feedback
of symptom improvement during the procedure.
[0095] Referring now to FIGS. 13A-13G, distraction may also be
achieved via duck-billed distraction device 200. The duckbill
comprises an upper pivoting member 204 and lower pivoting member
202 mounted to a tube 214 at hinge 206. A rasp 208 is mounted on
shaft 220 that is slideably received within the tube 214.
[0096] The distal tips 210 of the pivoting members 202, 204 are
configured to collapse down over rasp 208 to facilitate entry of
the duckbill into the facet joint cavity 30. Correspondingly, the
proximal ends 212 of the pivoting members 202, 204 expand outward
from tube 214. Once properly positioned within the cavity 30, the
proximal ends of the pivoting members 202, 204 (which are in an
expanded configuration), can be manually pressed inward toward the
shaft 214. This activation causes the duckbill to expand at distal
tips 210, and distract the facet joint 16.
[0097] With the facet joint surfaces 18, 22 distracted, the rasp
232 may be articulated distally outward from the duckbill and on to
the facet surfaces 18, 22. The rasp 208 may be reciprocated back
and forth within the tube 214 (via manual manipulation of the
proximal end of shaft 220), thereby decorticating (by sanding or
grating the surface) the surfaces in preparation for fusion.
[0098] FIGS. 14A-14I illustrate a standalone decorticator 230.
Decorticator 230 comprises a flat, flexible spatula-shaped rasp 232
at its distal end 236. The rasp 232 is coupled to shaft 238 that is
received inside a central channel running axially down handle 246.
The shaft and rasp protrude distally from the handle 246 so that
flat surface 242 running along the bottom of the rasp 232 is
exposed. The flat surface 242 facilitates introduction and
cooperation with the introducer 150 described above.
[0099] The shaft 238 has a beveled surface 240 that terminates at a
point proximal to the distal tip 236 of the rasp 232. The thin,
flexible shape allows the rasp to bend and access into the facet
joint from sub-optimal angles of entry. The rasp may have one or
more surfaces comprise a plurality of teeth 234 configured to grate
down the hard cortical surface of the opposing facet joint surfaces
18, 22.
[0100] Alternative decorticating devices may include a flat device
with an aggressive cutting surface that is rolled to achieve
roughening of the facet surface (not shown), and a device with two
opposing rasp surfaces that articulate in a lateral motion through
a "scissor like" activation feature. In such a configuration, the
two blades of the scissors have flat upper and lower roughened
surfaces that would simultaneously decorticate the opposing
subchondral surfaces by remote manipulation of the blades. In other
embodiments, decorticating devices may take the form of an abraded
shaft and decorticating may be performed by rolling the device. In
yet other embodiments, decorticating device may take the form of a
file mechanism and decorticating may be performed with a back and
forth filing motion, where the decorticating device is positioned
and actuated using floss.
[0101] With the facet joint 16 distracted and decorticated, the
method of the present invention includes an embodiment where a
specifically shaped piece of structural bone allograft (not shown)
is then inserted into the space of distraction between the opposing
facet joint surfaces. The bone allograft may be one of a series or
kit of bone allograft having a predetermined shape and size (e.g.
be sized in thickness that vary by small increments). The bone
allograft may then be further shaped by the physician to have a
custom size and shape correlating to the specific anatomy of the
patient to be treated.
[0102] The bone allograft is further supplemented with an
injectable biomaterial such as bone morphogenic protein (BMP) to
supplement the fusion potential at this level. FIGS. 15A-15G
illustrate an injection device 260 for injecting BMP or like
substances in accordance with the present invention. In some
embodiments, the injectable biomaterial is used alone without a
bone allograft. In either case, the injectable biomaterial may take
the form of BMP as mentioned or other injectable biomaterials such
as, but not limited to OP1, bonegraft, stem cells, bone cement
(PMMA), or other injectable biomaterials now known or later
developed.
[0103] Device 260 includes an elongate handle 268 having a flat
cutting blade 264 on its distal end 262. The blade 264 generally
comprises a straight, flat (i.e. planar), leading edge at distal
tip 262. Although the leading edge 262 is shown as a straight-line
surface when viewed from above in FIG. 15C, it is appreciated that
different shapes may also be utilized, (e.g. arcuate, triangular,
etc.)
[0104] The blade 264 is coupled to shaft 272 that is received
inside a central channel running axially down handle 268. The shaft
and blade protrude distally from the handle 268 so that flat
surface 266 running along the bottom of the blade 262 is exposed.
The flat surface 266 facilitates introduction and cooperation with
additional instruments such as introducer 150.
[0105] The shaft 272 has a beveled surface 274 that terminates at a
point on the distal tip 262 of blade 264. The beveled surface 274
allows the blade 112 to access into the facet joint from
sub-optimal angles of entry, and wedge the blade into the joint for
treatment.
[0106] The blade 264 and shaft 272 correspondingly have a D-shaped
cross-section. Accordingly, the chamber of handle 268 also has a
D-shaped cross-section, and is sized to receive shaft 272 and blade
264 with a snug fit.
[0107] The shaft has one or more channels 276 that run axially down
the length of the shaft to deliver an injectable biomaterial from
lines 280 located at the proximal end 270 of handle 268 to the
distal tip 262 of the device. Thus, with the distal tip 262
positioned in the facet joint cavity 230, bmp is delivered though
channels 276 to distal tip 262 at the treatment site.
[0108] Distraction may also be accomplished via insertion of an
inflatable membrane in the joint 16. FIGS. 16A-16I illustrate an
insertion device 300 for inserting inflatable membrane 302 into the
facet joint in accordance with the present invention.
[0109] The insertion device 300 comprises a handle 316 at its
proximal end 318, and a malleable "spatula" shaped tip 306 at its
distal end 308.
[0110] The tip 306 generally comprises a straight, flat leading
edge at distal end 308. Although the leading edge 308 is shown as a
straight-line surface when viewed from above in FIG. 16A, it is
appreciated that different shapes may also be utilized, (e.g.
arcuate).
[0111] The tip 306 is coupled to shaft 310 that is received within
a D-shaped opening channel of the handle 316. The shaft 310 and tip
306 protrude distally from the handle 316 so that flat surface 314
running along the bottom of the tip and shaft is exposed. The shaft
310 has a beveled surface 312 that terminates at a point proximal
to the distal tip end 308 of tip 306.
[0112] Inflatable membrane 302, in accordance with the present
invention, has a pocket 304 such that the inflatable membrane 302
can be disposed on distal end 308, and delivered through opening 32
created by the access tool 100 and into the cavity 30. Delivery
into the cavity may be guided by sliding lower surface 314 along
introducer 150. Once the inflatable membrane 302 is positioned in
the proper location within cavity 30, inflation medium is delivered
through line 330 running axially along shaft 310 from proximal end
318 to distal tip 308, and the inflatable membrane 302 is expanded
inside the joint 30. The inflatable membrane 302 generates a force
on the opposing facet surfaces and distracts the joint. With the
added pressure, the insertion device 300 is simply just pulled out
of the joint, with the tip 306 sliding out of pocket 304 while the
inflatable membrane 302 retains its position.
[0113] The malleable and thin planar shape of the "spatula" tip 306
and beveled shaft 312 allow for suboptimal entry angles and
compensates for the narrow spacing of the facet joint. Thus, the
inflatable membrane 302 may be delivered from a less invasive, by
non-aligned orientation.
[0114] The delivered implant is configured to distract the joint
and reverse narrowing of the nerve root canal 38 and alleviate
symptoms of cervical stenosis. However, it is also within the scope
of the present invention to size the implant according to other
spinal conditions, for example to correct for cervical kyphosis or
loss of cervical lordosis
[0115] The process for achieving indirect cervical decompression
and fusion may also include posterior stabilization with any number
of commercially available implants & instrument sets available
in the art.
[0116] Although the embodiments disclosed above are directed
primarily to installation in the cervical facet joint, it is
contemplated that the devices and methods may also be used to
increase foraminal dimension in other regions of the spine, e.g.
thoracic, lumbar, etc.
[0117] Although the description above contains many details, these
should not be construed as limiting the scope of the invention but
as merely providing illustrations of some of the presently
preferred embodiments of this invention. Therefore, it will be
appreciated that the scope of the present invention fully
encompasses other embodiments which may become obvious to those
skilled in the art, and that the scope of the present invention is
accordingly to be limited by nothing other than the appended
claims, in which reference to an element in the singular is not
intended to mean "one and only one" unless explicitly so stated,
but rather "one or more." All structural, chemical, and functional
equivalents to the elements of the above-described preferred
embodiment that are known to those of ordinary skill in the art are
expressly incorporated herein by reference and are intended to be
encompassed by the present claims. Moreover, it is not necessary
for a device or method to address each and every problem sought to
be solved by the present invention, for it to be encompassed by the
present claims. Furthermore, no element, component, or method step
in the present disclosure is intended to be dedicated to the public
regardless of whether the element, component, or method step is
explicitly recited in the claims. No claim element herein is to be
construed under the provisions of 35 U.S.C. 112, sixth paragraph,
unless the element is expressly recited using the phrase "means
for."
[0118] Although this invention has been disclosed in the context of
certain preferred embodiments and examples, it will be understood
by those skilled in the art that the present invention extends
beyond the specifically disclosed embodiments to other alternative
embodiments and/or uses of the invention and obvious modifications
and equivalents thereof. Thus, it is intended that the scope of the
present invention herein disclosed should not be limited by the
particular disclosed embodiments described above, but should be
determined only by a fair reading of the claims that follow.
* * * * *