U.S. patent application number 12/408525 was filed with the patent office on 2009-07-16 for implant device used in minimally invasive facet joint hemi-arthroplasty.
Invention is credited to David A. Petersen.
Application Number | 20090182377 12/408525 |
Document ID | / |
Family ID | 36461925 |
Filed Date | 2009-07-16 |
United States Patent
Application |
20090182377 |
Kind Code |
A1 |
Petersen; David A. |
July 16, 2009 |
IMPLANT DEVICE USED IN MINIMALLY INVASIVE FACET JOINT
HEMI-ARTHROPLASTY
Abstract
A metallic inverted L-shaped implant is used to resurface the
superior facet of the inferior vertebrae limited to the facet
joints located on the spine, Occiput-C1 through L5-S1. The metallic
implant is highly polished on its exterior and textured on its
interior surface. It is mechanically crimped in place without the
use of cement or pedicle screws. Permanent fixation occurs when
bone in-grows onto a rough, porous surface on the inside of the
implant. The implant employed in a hemi-arthroplasty method
resurfaces half of the facet joint to provide for smooth, pain free
joint articulation in deteriorated or diseased spinal facet joints
without the need for major surgery or rehabilitation at
considerably less risk to the patient.
Inventors: |
Petersen; David A.;
(Clearwater, FL) |
Correspondence
Address: |
DON J. PELTO;Sheppard, Mullin, Richter & Hampton LLP
1300 I STREET, NW, 11TH FLOOR EAST
WASHINGTON
DC
20005
US
|
Family ID: |
36461925 |
Appl. No.: |
12/408525 |
Filed: |
March 20, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11177467 |
Jul 8, 2005 |
7517358 |
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12408525 |
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10992746 |
Nov 22, 2004 |
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11177467 |
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Current U.S.
Class: |
606/247 |
Current CPC
Class: |
A61F 2/4405 20130101;
A61F 2002/30884 20130101; A61F 2002/4635 20130101; A61F 2310/00029
20130101; A61F 2002/30841 20130101 |
Class at
Publication: |
606/247 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Claims
1-17. (canceled)
18. A prosthetic implant for use in minimally invasive facet joint
hemi-arthroplasty, the implant comprising: an inverted L-shaped a
metallic body comprising a convex top portion integral at a rear
edge with a concave downwardly descending portion, the top and
downwardly descending portions having a highly polished exterior
surface of a material biocompatible with bone; a concave lower
surface under the top portion and convex inner textured surface on
the downwardly descending portion; and at least one blade integral
with the convex inner textured surface and a pair of teeth
descending from a front edge of the convex top portion, wherein the
at least one blade is positioned and configured to provide lateral
stability when the implant is inserted into the facet joint and
wherein the pair of teeth provides temporary fixation of the
implant into the bone when the implant is inserted.
19. The implant of claim 18 wherein the highly polished exterior
surface of the implant is a cobalt-chrome alloy.
20. The implant of claim 18 wherein the highly polished exterior
surface of the implant is a titanium alloy.
21. The implant of claim 18 wherein the convex inner textured
surface of the implant is porous and compatible with bone.
22. The implant of claim 18 further comprising two blades integral
with the convex inner textured surface, wherein the two blades are
positioned and configured to provide lateral stability when the
implant is inserted into the facet joint.
23. The implant of claim 18 further configured to be mounted within
the facet joint such that the highly polished exterior surface is
juxtaposed to oppositely positioned bones in the facet joint.
24. The implant of claim 18 further configured to be mounted within
the facet joint such that the textured surface conforms to the
shape of a juxtaposed bone.
25. The implant of claim 22 further configured to be mounted within
a facet joint such that the textured surface conforms to the shape
of a juxtaposed bone and the two blades cut into the juxtaposed
bone, and wherein the two blades are positioned and configured to
provide lateral stability when the implant is inserted into the
facet joint.
26. The implant of claim 18 further configured to be crimped into
place in the facet joint.
27. The implant of claim 26 wherein the pair of teeth are
configured to be pressed to downwardly into the bone to crimp the
implant into place.
28. The implant of claim 26 further configured to be crimped into
place using an impactor to impact the implant into place in the
facet joint.
29. The implant of claim 26 further configured to be crimped into
place without the use of screws or cement.
30. An apparatus for performing minimally-invasive facet joint
arthroplasty, comprising: an inverted L-shaped prosthetic implant
comprising: a metallic body having a convex top portion integral at
a rear edge with a concave downwardly descending portion, the top
and downwardly descending portions having a highly polished
exterior surface of a material biocompatible with bone; a concave
lower surface under the top portion and convex inner textured
surface on the downwardly descending portion; and at least one
blade integral with the convex inner textured surface and a pair of
teeth descending from a front edge of the convex top portion; the
implant configured to be mounted within the facet joint such that
the highly polished exterior surface is juxtaposed to oppositely
positioned bones in the facet joint and such that the textured
surface conforms to the shape of a juxtaposed bone, wherein the at
least one blade is positioned and configured to provide lateral
stability when the implant is inserted into the facet joint and
wherein the pair of teeth provides temporary fixation of the
implant into the bone when the implant is inserted into the facet
joint; and the implant further configured to be crimped into place
in the facet joint.
31. The apparatus of claim 30 wherein the highly polished exterior
surface of the implant is a cobalt-chrome alloy.
32. The apparatus of claim 30 wherein the highly polished exterior
surface of the implant is a titanium alloy.
33. The apparatus of claim 30 wherein the convex inner textured
surface of the implant is porous and compatible with bone.
Description
PRIOR APPLICATION
[0001] This application is a continuation-in-part from application
Ser. No. 10/992,746, filed Nov. 22, 2004.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to a device for use
in minimally invasive spine surgery. More particularly, it refers
to a pre-made, pre-shaped metallic implant implanted using an
arthroscopic type portal or classic open surgical method to achieve
a spinal facet joint hemi-arthroplasty to resurface any or all of
the forty-eight superior facets of the inferior Occiput-C1 through
L5-S1 vertebrae.
[0003] In the United States alone, about 10% of the entire
population will suffer from back pain sometime in the next twelve
months. More people will contract back pain in the next year than
any other injury or disease except the common cold and flu. About
one-third will not recover and have to live with persistent,
disabling symptoms. The number is cumulative year after year.
[0004] One of the root causes of back pain, particularly persistent
and disabling back pain, are facet joints, small joints located
behind adjacent vertebrae in the spine that allow for spinal
motion.
[0005] Present surgical solutions available for the millions of
people with facet joint dysfunctions are complex, invasive,
high-risk operations requiring pedicle screws for fixation and
significant reduction or elimination of natural joints and
replacement with prosthetic apparatus such as those described in
U.S. Pat. Nos. 6,610,091, 6,579,319, 6,132,464, 6,113,637 and U.S.
Patent Application 2003/0028250. In general, the present art
requires prolonged recovery times, from six to twenty-four months,
and offers uncertain outcomes. High risk equates to frequent
litigation, which forces non-surgical symptomatic treatment while
the disease or consequences of injury progressively worsen.
[0006] With the advent of new, safer and less invasive surgical
techniques and technology, the growth of spine surgery now outpaces
every other orthopedic surgery segment. Its growth is further
fueled by an enormous demand. Improvements in devises used in
spinal joints is needed.
SUMMARY OF THE INVENTION
[0007] The present invention provides a pre-made pre-shaped
metallic implant for use in minimally invasive spine surgery. The
use of a pre-shaped metallic overlay of this invention for facet
joint resurfacing of diseased, painful, deteriorated or
overstressed joints offers three distinct advantages over larger
prosthetic implants; namely, (1) using a thin metallic overlay
allows for minimally invasive insertion that is safer, less
traumatic and requires far less recovery time compared to a
prosthetic; (2) the overlay does not require the use of cements,
pedicle screws or other fixation methods that can work their way
loose over time; and, (3) the implant has two fins or blades to
provide lateral stability and two teeth to provide temporary
fixation and a rough or porous inner surface amenable to bone in
growth providing permanent natural fixation. The implant also has a
polished outside that allows for smooth, natural, pain free
articulation of the joint.
[0008] The implant is specifically designed for use in an
arthroscopic type portal for standalone procedures, but also may be
used in classic open surgery. This implant provides a unique,
stronger and superior resurfacing and may be used for, but not
limited to: (1) an adjunct to instrumented vertebral fusion when
implanted in the two facet joints immediately above and below the
two joints adjoining the instrumentation thereby eliminating the
risk of collateral post-operative facet joint pain resulting from
additional stress placed on facet joints, (2) when used to
resurface adjoining facet joints directly above and below a disk
replacement by eliminating the risk of collateral post-operative
facet joint pain resulting from additional stress placed on facet
joints by the disk replacement, and, (3) as a stand along treatment
for diseased, painful or deteriorated facet joints.
[0009] The invention accomplishes its goal of resurfacing a
painful, diseased or deteriorated spinal facet joints by providing
a resurfacing implant to replace the joint surface with a small
metal on bone overlay. The overlay, constructed of cobalt chrome or
such other biocompatible metal or metallic alloy appropriate for
joint hemi-arthroplasties, is one of several sizes for various
segments of the spine, similarly sized for different facet joints
or groups of joints in the spine and are attached to the joint
using a straightforward process without the need for screws or
cements. The facet joints may be accessed using an arthroscopic
type portal eliminating the need for open surgery, hospitalization
and long recovery periods. The procedure also may be performed as
an adjunct to other procedures such as instrumented fusion and disc
replacement in a traditional open surgery. Because the side of the
implant that attaches to bone is porous, the bone heals onto it,
permanently fixing it into place. A uniquely designed set of blades
and teeth provides temporary fixation to the joint and prevents
migration. A crimping system allows the implant to be fixed into
place, holding it firmly until bone in growth is complete. The side
making contact with the joint is highly polished providing a
smooth, virtually frictionless surface that undergoes virtually no
wear and tear. The inside is rough or porous providing an amenable
surface for bone in growth.
[0010] According to one broad aspect of the invention, a unique
metallic prosthetic overlay is provided. The metallic overlay is
generally shaped to the naturally shaped contour of the bone it
resurfaces and is highly polished on the outside to provide
frictionless articulation of the joint and rough or porous on the
inside to promote and provide a surface to allow the natural bone
to grow into the overlay, providing a permanent fixation. In the
interim between implantation and bone in-growth, the overlay is
mechanically crimped into place using two teeth opposed to each
other and one to two blades on the inside of the implant that bite
into the bone to prevent lateral migration. The overlay is further
held into place by the natural pressure of the inferior and
superior sides of the joint as they come together in their natural
position.
[0011] The system to insert the prosthetic overlay includes any
number of instruments allowing preparation of the joint and the
implant to be placed using a minimally invasive surgical
arthroscopic technique to access to the joint that include a
director probe to determine the correct facet joint angle, a
separator to assist with separation of the vertebrae to improve
access to the joint, an osteotome to make a small cut in the bone
to prepare the surface for the implant, a broach to prepare the
bone to match the implant shape, an impactor to impact the implant
into place and a crimp to fix the implant to prevent migration
prior to healing and a unique implant. By way of example only, the
director may include a planer blade or rasp to remove any bone
spurs or overgrowth and to flatten the facet joint surface in
preparation for implant placement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Many advantages of the present invention will be apparent to
those skilled in the art with a reading of this specification in
conjunction with the attached drawings, wherein like reference
numerals are applied to like elements and wherein:
[0013] FIG. 1 shows a top right isometric view of the implant;
[0014] FIG. 2 shows a bottom left isometric view of the
implant;
[0015] FIG. 3 shows a sectional view along line 3-3 of FIG. 1;
[0016] FIG. 4 shows a perspective view of a tool used to prepare
the facet joint for receipt of the implant;
[0017] FIG. 5 shows the tool inserted in the facet joint;
[0018] FIG. 6 shows the insert about to be installed in the facet
joint;
[0019] FIG. 7 shows the insert embedded in the facet joint;
[0020] FIG. 8 shows a sectional view along line 8-8 in FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Referring to FIG. 1, the prosthetic implant 10 of this
invention has a highly polished concave outside back portion 12 and
a convex highly polished surface on a top portion 14. The highly
polished surface is a cobalt-chrome alloy, a titanium alloy or
other biologically acceptable material capable of forming a smooth
highly polished surface. Referring to FIG. 2, an inside convex
surface is textured 18 to encourage new bone growth and adhesion.
Blades 20 and 22 attached to inside surface 16 bite into bone to
promote adhesion. The bottom surface 24 of the top portion of
implant 10 is concave to fit tightly over a bone as shown in FIGS.
7 and 8. Teeth 26 and 28 are used for imbedding into adjacent bone
to prevent movement of implant 10.
[0022] Prior to imbedding the implant in the facet joint 32, a
preparation tool 30 is used to slightly spread the joint 32. Tool
end 34 is inserted into the joint 32 to provide sufficient space
for inserting implant 10 into joint 32 as seen in FIGS. 7 and
8.
[0023] The use of the prosthetic implant 10 has two advantages over
the prior art.
[0024] 1. It is minimally invasive, low risk, fast (about 20
minutes per joint in an outpatient setting compared to about three
hours in a hospital followed by a three day stay), and has a
recovery time measured in a few weeks (compared to six to
twenty-four months); and
[0025] 2. It has a high success rate, does not preclude other
surgical options, and is non-limiting and permanent.
[0026] The present invention is directed at overcoming, or at least
improving upon, the disadvantages of the prior art by achieving the
following: [0027] Reversal of the risk/benefit ratio of the present
procedures versus the invention; [0028] A stand-alone minimally
invasive procedure versus major open surgery; [0029] Employed as an
adjunct to major open surgery in concert with long fusion and with
disc replacement surgery to strengthen adjacent facet joints.
[0030] Outpatient versus inpatient surgery (about 20 minutes per
joint versus hours); [0031] Reduced morbidity; [0032] Reduced blood
loss; [0033] Reduced time under anesthesia; [0034] Reduced risk;
[0035] Recovery time dramatically reduced; [0036] Minimal scarring
that decreases the risk of failed back syndrome and improves
revisions surgery outcome; [0037] Reduced risk of post operative
infection by significantly reducing operating room time and soft
tissue destruction; [0038] Prolonging the functional life of long
segment fusions and disc replacement. [0039] No preclusion of other
surgical or non-invasive treatment options; and, [0040] Projected
high success rate by utilizing accepted procedures facilitated
through an arthroscopic technique and resurfacing implant.
[0041] It is anticipated that the availability of this method,
instrumentation and implant will increase the number of surgeries
performed because they offer the first safe outpatient solution to
a predominant cause of joint pain. The inventor also expects that
virtually all patients receiving this procedure will be able to
walk the same day as surgery and be fully functional within a few
weeks. Present surgical solutions require hospitalization of about
three days and six to twenty-four months' recovery.
[0042] Aside from the obvious positive clinical outcome, the
significant favorable financial impact on disability, worker's
compensation and health care insurers is considerable.
[0043] Spinal facet implant units are calculated per joint. Each
patient has two joints per spinal segment and six segments (T12 to
L1 through L5-S1) in the lumbar spine, or twelve lumbar, fourteen
cervical and twenty-eight thoracic joints. Each surgery is likely
to involve multiple joints, with a probable average of four per
patient.
[0044] The invention accomplishes its goal of reducing, preventing
or eliminating spinal facet joint pain by providing a resurfacing
implant to replace the joint surface with a small metal on bone
overlay. The overlay, constructed of cobalt chrome, a material
previously approved by the FDA for other joint hemi-arthroplasty,
or such other metallic construction as may be safely used, is one
of several sizes for various segments of the spine, may be
similarly sized for different joints and is attached to the joint
using a straightforward process without the need for screws or
cements with the aid of custom designed instruments. The joint is
accessed using an arthroscopic type portal eliminating the need for
open surgery, hospitalization and long recovery periods (unless the
procedure is performed as an adjunct to other procedures such as
instrumented fusion and disc replacement in a traditional open
surgery). Because the side that attaches to bone is porous, the
bone heals onto it, permanently fixing it into place. A uniquely
designed set of blades and teeth prepares the joint and a unique
crimping system allows the implant to be fixed into place, holding
it firmly until bone in growth is complete. The side making contact
with the joint is highly polished providing a smooth, virtually
frictionless surface that undergoes virtually no wear and tear. The
resurfacing implant is a securely fixed porous hemi-arthroplasty of
the facet joints of the spine.
[0045] The metallic overlay is generally shaped to the natural
contour of the bone it resurfaces and is highly polished on the
outside to provide frictionless articulation of the joint and rough
and porous on the inside to promote and provide a surface to allow
the natural bone to grow into the overlay, providing a permanent
fixation. In the interim between implantation and bone in-growth,
the overlay is mechanically crimpled into place using two teeth
opposed to each other that bite into the bone to prevent migration.
The overlay is further held into place by the natural pressure of
the inferior and superior sides of the joint as they come together
in their natural position.
[0046] The system includes any number of instruments 30 allowing
preparation of the joint 32 and the implant 10 to be placed using a
minimally invasive surgical arthroscopic technique to access to the
joint that include a director probe to determine the correct facet
joint angle, a separator to assist with separation of the vertebrae
to improve access to the joint, an osteotome to make a small cut in
the bone to prepare the surface for the implant, a broach to
prepare the bone to match the implant shape, an impactor to impact
the implant into place and a crimp to fix the implant to prevent
migration prior to healing and a unique implant. By way of example
only, the director may include a planer blade or rasp to remove any
bone spurs or overgrowth and to flatten the facet joint surface in
preparation for implant placement.
[0047] Equivalent elements can be substituted for the elements of
the implant of this invention to provide substantially the same
function in substantially the same way to achieve substantially the
same result.
* * * * *