U.S. patent application number 10/032778 was filed with the patent office on 2003-06-26 for implant retaining device.
Invention is credited to Kaes, David R., Morris, John W., Shimp, Lawrence A..
Application Number | 20030120274 10/032778 |
Document ID | / |
Family ID | 26708877 |
Filed Date | 2003-06-26 |
United States Patent
Application |
20030120274 |
Kind Code |
A1 |
Morris, John W. ; et
al. |
June 26, 2003 |
Implant retaining device
Abstract
There is provided an implant retaining device, which has the
effect of preventing an intervertebral implant from jutting out of
the receiving bed. The implant retaining device generally includes
a plate having at least one throughbore to receive a screw, and a
screw for securing the plate to the vertebrae. The plate may be
dimensioned to cover a portion of the opening of a receiving bed,
and thus, need only be secured to a single vertebral body. In an
alternate embodiment, the plate may be used during bone fracture
correction procedures to prevent a bone screw from backing out of
engagement with adjacent bone sections. A method of retaining an
intervertebral implant using the device is also provided.
Inventors: |
Morris, John W.; (Beachwood,
NJ) ; Shimp, Lawrence A.; (Morganville, NJ) ;
Kaes, David R.; (Toms River, NJ) |
Correspondence
Address: |
Peter G. Dilworth
DILWORTH & BARRESE, LLP
333 Earle Ovington Blvd.
Uniondale
NY
11553
US
|
Family ID: |
26708877 |
Appl. No.: |
10/032778 |
Filed: |
October 22, 2001 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60242051 |
Oct 20, 2000 |
|
|
|
Current U.S.
Class: |
606/279 ;
606/246; 606/247; 606/286; 606/909 |
Current CPC
Class: |
A61F 2310/00179
20130101; A61B 2017/00831 20130101; A61F 2002/2817 20130101; A61F
2/4455 20130101; A61F 2/446 20130101; A61B 17/80 20130101; A61F
2310/00359 20130101; A61B 17/86 20130101; A61F 2/447 20130101; A61B
17/7059 20130101; A61F 2/28 20130101; A61F 2/442 20130101; A61F
2002/3079 20130101; A61F 2220/0008 20130101; A61F 2/30749
20130101 |
Class at
Publication: |
606/61 ;
606/69 |
International
Class: |
A61B 017/58 |
Claims
What is claimed is:
1. An implant retaining device comprising: a body dimensioned to
cover at least a portion of an opening to a receiving bed formed
between adjoining vertebral bodies, the body having a single
throughbore dimensioned to receive a screw; and a screw for
securing said body to one of the adjoining vertebral bodies.
2. The implant retaining device as recited in claim 1, wherein said
body has a rectangular configuration.
3. The implant retaining device as recited in claim 1, wherein said
body has a circular configuration.
4. The implant retaining device as recited in claim 1, wherein said
body is curved along its longitudinal axis.
5. The implant retaining device as recited in claim 1, wherein said
body is curved along its transverse axis.
6. The implant retaining device as recited in claim 1, wherein said
body is in the form of a plate.
7. The implant retaining device as recited in claim 1, wherein said
body is formed from partially demineralized bone.
8. A method of retaining an intervertebral implant within a
receiving bed formed between adjoining vertebral bodies, the method
comprising the following steps: providing a retaining plate having
at least one throughbore for receiving a bone screw, the retaining
plate being dimensioned to extend at least partly across a disk
space defined between the adjoining vertebral bodies, and attaching
the retaining plate to only one of the adjoining vertebral bodies
such that the retaining plate extends at least partly across the
disk space between the vertebral bodies.
9. The method as recited in claim 8, wherein said plate has a
rectangular configuration.
10. The method as recited in claim 8, wherein said plate has a
circular configuration.
11. The method as recited in claim 8, wherein said plate is curved
along its longitudinal axis.
12. The method as recited in claim 8, wherein said plate is curved
along its transverse axis.
13. The method as recited in claim 8, wherein said plate is formed
from bone.
14. The method as recited in claim 13, wherein the bone is cortical
bone.
15. The method as recited in claim 13, wherein the bone is
partially demineralized bone.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Serial No. 60/242,051 filed Oct. 20, 2000, the contents
of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present disclosure is directed to an implant retaining
device for preventing an implant from backing out of a receiving
bed or graft site formed in body tissue. More specifically, the
present disclosure is directed to an implant retaining device
particularly suited for retaining an intervertebral implant in a
receiving bed formed between adjacent vertebrae.
[0004] 2. Background of Related Art
[0005] The spine is a flexible column formed of a series of bone
called vertebrae. The vertebrae are hollow and piled one upon the
other, forming a strong hollow column for support of the cranium
and trunk. The hollow core of the spine houses and protects the
nerves of the spinal cord. The vertebrae are connected together by
means of articular processes and intervertebral,
fibro-cartilages.
[0006] The intervertebral fibro-cartilages are also known as
intervertebral disks and are made of a fibrous ring filled with
pulpy material. The disks function as spinal shock absorbers and
also cooperate with synovial joints to facilitate movement and
maintain flexibility of the spine. When one or more disks
degenerate through trauma, spondylolisthesis or other pathologies,
nerves passing near the affected area may be compressed and are
consequently irritated. The result may be chronic and/or
debilitating back pain. Various methods and apparatus, both
surgical and non-surgical, have been designed to relieve such back
pain.
[0007] One method designed to relieve such back pain is interbody
spinal fusion. Typically, interbody spinal fusion involves
distracting adjoining vertebrae of the spine so that the nerve root
canal sizes are increased and nerve irritation is eliminated or
reduced. In order to maintain the adjoining vertebrae in a
distracted state, at least one intervertebral implant is inserted
into a receiving bed formed in the disk space between the adjoining
vertebrae. The implant is positioned to engage the adjoining
vertebrae to maintain the vertebrae at a fixed degree of
distraction.
[0008] Preferably, the implant should become fused to adjoining
vertebrae in order to prevent the implant and adjoining vertebrae
from moving. The implant must also provide spinal load support
between the vertebrae. Further, during the time it takes for
fusion, i.e., biological fixation of the vertebrae, to be
completed, the implant should have enough structural integrity to
maintain the disk space without substantial degradation or
deformation of the implant.
[0009] To facilitate rapid bone growth, the implant may include or
be provided with a bone growth material. The material from which
the implant is constructed should be a biocompatible material and,
preferably, interact biologically with the body's own naturally
occurring tissues.
[0010] In order to have successful spinal fusion and maintain the
stability of the spine, the vertebral implant must be fixedly
positioned in relation to the adjoining vertebrae during the entire
period required for fusion to occur. However, the everyday activity
of a patient who has undergone a spinal fusion procedure may lead
to progressive mechanical loosening and eventual failure of the
implant. This significantly decreases the chances of obtaining
successful fusion of the implant and the adjoining vertebrae.
Therefore, it is imperative that the implant be fixedly retained in
the intervertebral space during the period required for spinal
fusion.
[0011] A variety of different devices have been developed to retain
an intervertebral implant at a fixed position within the
intervertebral space. These devices include, inter alia, screws and
formations formed on the implant itself. Such devices often inhibit
insertion of the implant into the intervertebral space.
[0012] Accordingly, a need exists for an improved implant retaining
device which is configured to reduce the likelihood of expulsion or
retropulsion of an intervertebral implant from between adjoining
vertebrae during normal patient activity, without inhibiting
insertion of the implant into the intervertebral space.
SUMMARY
[0013] In accordance with the present disclosure, an implant
retaining device is provided which prevents expulsion of an
intervertebral implant from an intervertebral receiving bed. In one
embodiment the implant retaining device includes a plate having at
least one throughbore dimensioned to receive a screw. Single or
multiple screws can be used to secure the plate to the vertebrae.
The plate may have a rectangular, circular, or any other
configuration capable of performing the intended function of
preventing expulsion of an intervertebral implant from the
receiving bed.
[0014] The plate can be secured to one or both vertebral bodies to
prevent the intervertebral implant from backing out of the
receiving bed. The plate may be dimensioned to cover a portion of
the opening of a receiving bed, and thus, need only be secured to a
single vertebral body. Alternately, the plate may be dimensioned to
extend entirely across the disc space and may be secured to one or
both of the vertebral bodies.
[0015] When the plate is formed from bone, it may be partially or
fully demineralized. Partially demineralized bone provides a degree
of flexibility to the plate such that it can be manipulated to
conform to the surface to which it is secured, e.g., the vertebrae.
Demineralization also improves the osteoconductive and
osteoconductive characteristics of the plate.
[0016] In an alternate embodiment, the plate may be used in
surgical procedures other than spinal interbody fusion procedures.
For example, the plate may be used during bone fracture correction
procedures to prevent a bone screw from backing out of engagement
with adjacent bone sections.
[0017] Also disclosed herein is a method of retaining an
intervertebral implant in a receiving bed using the disclosed
implant retaining device. The method includes attaching a plate,
dimensioned to cover at least a portion of the receiving bed, to a
vertebral body and securing the upper portion of the plate to the
vertebral body utilizing at least one screw. Alternately, the
method includes attaching a plate to adjacent vertebral bodies
using at least two screws.
BRIEF DESCRIPTION OF TIE DRAWINGS
[0018] Various preferred embodiments of the presently disclosed
implant retaining device are described herein with reference to the
drawings wherein:
[0019] FIG. 1A is a perspective view of one preferred embodiment of
the presently disclosed implant retaining device having a
rectangular configuration;
[0020] FIG. 1B is a perspective view of another preferred
embodiment of the presently disclosed implant retaining device
having a rectangular configuration aid a curvature along its
transverse axis;
[0021] FIG. 1C is a top view of another preferred embodiment of the
presently disclosed implant retaining device having a circular
configuration;
[0022] FIG. 1D is a perspective view of another preferred
embodiment of the presently disclosed implant retaining device
having a rod shaped configuration;
[0023] FIG. 2 is a front view of the implant retaining device shown
in FIG. 1A secured to a vertebral body with a pair of screws;
[0024] FIG. 3 is a side view of the implant retaining device shown
in FIG. 1A secured to a vertebral body with a bone screw to retain
a concave implant between adjacent vertebral bodies;
[0025] FIG. 4 is a side view of the implant retaining device shown
FIG. 1A secured to a vertebral body with a bone screw to retain a
cylindrical dowel between adjacent vertebral bodies;
[0026] FIG. 5 is a side view of the implant retaining device shown
in FIG. 1A utilized in a bone fracture correction procedure to
prevent a bone screw from backing out of engagement with adjacent
bone sections; and
[0027] FIG. 6 is a cross-sectional view of another embodiment of
the presently disclosed implant retaining device having a stepped
bore configured to receive the head of a bone screw.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0028] Preferred embodiments of the presently disclosed implant
retaining device will now be described in detail with reference to
the drawings in which like reference numerals designate identical
or corresponding elements in each of the several views.
[0029] The implant retaining device of the present invention is
intended to be attached to at least one vertebral body, to cover at
least a portion of the disk space to prevent a vertebral implant
from backing out of a receiving bed. The implant retaining device
is especially suited for procedures where it would be desirable to
prevent an implant from backing out of the spine. However, it is
entirely suitable to applications involving the repair of other
bony sites in the body.
[0030] In humans, the device may be used predominately in the
lumbar and thoracic regions of the spine, but, is adaptable for use
in the cervical spine and other regions of the body as well.
[0031] The implant retaining device described herein may be formed
of any biocompatible material or combination of materials.
"Biocompatible" means that no serious systemic toxicity is caused
by the presence of the material in a living system. It is
contemplated that biocompatible materials may cause some clinically
acceptable amounts of toxicity including irritation and/or other
adverse reactions in certain individuals. For example, the material
described in U.S. Pat. No. 5,899,939, the contents of which are
incorporated herein by reference, may be entirely suitable for
fabricating all or a portion of the implant retaining device
described herein.
[0032] The implant retaining device may also be fabricated from any
of the various biocompatible polymers. Examples of biocompatible
polymers suitable for use herein would include bioabsorbable
polymeric materials such as, for example, polymers and/or
copolymers containing any of the following polymerizable monomers:
epsilon-caprolactone, glycolide, trimethylene carbonates,
tetramethylene carbonates, dimethyl trimethylene carbonates;
dioxanones; dioxepanones; absorbable cyclic amides; absorbable
cyclic ether-esters derived from crown ethers; hydroxyacids capable
of esterification, including both alpha hydroxyacids (such as
glycolic acid and lactic acid) and beta hydroxyacids (such as beta
hydroxybutyric acid and gamma hydroxyvaleric acid); polyalkyl
ethers (such as polyethylene glycol and polypropylene glycol and
combinations thereof), etc. Of course non-bioabsorbable polymers
that are biocompatible such as, for example,
polytetrafluoroethylene, would also be suitable for fabricating any
or all of the components of the implant retaining device described
herein.
[0033] The implant retaining device may also be fabricated from
metallic materials commonly used in the fabrication of implantable
devices, for example, surgical stainless steel, titanium, titanium
alloys, etc. Ceramic materials such as, hydroxyapatite, bioglass,
etc., may also be used for the fabrication of the device described
herein. Of course, any combination of materials may be used to
fabricate the entire implant retaining device described herein as
well as the various components of the fixation system herein. Any
and all such combinations of biocompatible materials are envisioned
as being within the scope of the disclosure herein.
[0034] Referring to FIGS. 1A-D, implant retaining device 10
includes a plate 12 having at least one throughbore 14 dimensioned
to receive a screw 16 (see FIGS. 2-4). Plate 12 may vary in
thickness depending on the size and shape of the vertebral body and
the vertebral implant with which the plate 12 is being utilized.
The thickness of plate 12 may also vary depending on whether the
implant retaining device is adapted for use in the lumbar, thoracic
or cervical spinal regions, or other regions of the body. The
thickness of plate 12 may vary from at least about 0.5 mm to about
1.0 cm. Preferably, plate 12 is between about 2 mm to about 5 mm.
Plate 12 can be formed from any biocompatible material having the
requisite strength requirements including, as discussed above,
cancellous or cortical bone, ceramics, polymers, composites, etc.
Preferably, plate 12 is constructed from cortical bone. Plate 12
may have a rectangular configuration (FIG. 1A), a circular
configuration (FIG. 1C), a rod shaped configuration (FIG. 1D), or
any other configuration capable of performing the intended function
described herein. Plate 12 may also be provided with a curvature
along its longitudinal and/or transverse axis (FIG. 1B). The
curvature may be selected to correspond to the curvature of a
surface against which plate 12 is to be secured, e.g., a
vertebrae.
[0035] Referring to FIGS. 2-4, plate 12 is suitable for use in
preventing an intervertebral implant 20 from backing out of a
receiving bed 22 formed between adjacent vertebral bodies 24 and 26
during a spinal interbody fusion procedure. Intervertebral implants
include cylindrical dowels (FIG. 4), wedge-shaped implants,
rectangular spacers, concave or convex implants (FIG. 3), etc.
During an intervertebral implantation procedure, the intervertebral
implant 20 is placed between adjacent vertebral bodies to support
the vertebral bodies at a desired orientation and spacing to
facilitate spinal fusion. Such procedures are well known in the art
and will not be discussed in further detail herein.
[0036] After intervertebral implant 20 has been placed between
vertebral bodies 24 and 26, plate 12 can be secured to one or both
of the vertebral bodies 24 and 26 to prevent implant 20 from
backing out of receiving bed 22. As illustrated, plate 12 need only
be dimensioned to cover a portion of the opening of receiving bed
22, and thus, need only be secured to a single vertebral body. To
minimize damage to the vertebral bodies, attachment to a single
vertebral body is preferred. Alternately, plate 12 may be
dimensioned to extend entirely across the disc space and may be
secured to one or both of the vertebral bodies (not shown).
[0037] When plate 12 is formed from bone, it may be partially or
fully demineralized using, for example, a controlled acid
treatment. Plate 12 may be partially demineralized to provide a
degree of flexibility to the plate such that it can be manipulated
to conform to the surface to which it is secured, e.g., the
vertebrae. Alternately, plate 12 may be partially demineralized to
increase the osteoinductive characteristics of the plate. For
example, the surface of the plate to be secured adjacent to a
vertebral surface may be surface demineralized to promote
osteogenic growth.
[0038] In an alternate embodiment, plate 12 may be used in surgical
procedures other than spinal interbody fusion procedures. For
example, plate 12 may be used to prevent a bone screw 30 from
backing out of engagement with adjacent bone sections during bone
fracture correction procedures. See FIG. 5. In such a procedure,
after the bone screw has been screwed into the bone sections 40 and
42, plate 12 can be affixed over the head 44 of the bone screw 30
to prevent the bone screw 30 from backing out of the insertion
bore. As illustrated, a single screw 16 can be used to secure plate
12 to the bone section 42. Alternately, multiple screws can be used
to secure plate 12 to bone section 42, or bone sections 40 and 42,
e.g., one screw at each end of plate 12.
[0039] The screw 16 and/or bone screw 30 can be formed from any
biocompatible material having the requisite strength requirements
including surgical grade metals, cancerous or cortical is bone,
bone composites, polymers, BMP's, etc. Preferably, screws 16 and 30
are formed from cortical bone such as disclosed in U.S. application
Ser. No. 09/542,556, the entirety of which is hereby incorporated
by reference.
[0040] A method of using the implant retaining device is also
described herein. In use, plate 12 is attached to one or more
vertebral bodies 24 and 26 to prevent an intervertebral implant
from backing out of an intervertebral receiving bed. The plate is
dimensioned to cover at least a portion of the opening to the
receiving bed and may extend over the entire receiving bed opening.
Thereafter, the plate may be secured to one or both of the
vertebral bodies using a bone screw or screws. Alternately, other
fastening techniques may be used to secure the plate to the
vertebral body or bodies, e.g., nails, adhesives, pins, etc.
[0041] It will be understood that various modifications may be made
to the embodiments disclosed herein. For example, the plate 12 may
be constructed having a variety of configurations other than those
illustrated herein including rectangular, triangular, etc.
Moreover, multiple plates may be used simultaneously, i.e., one
plate may extend from each side of the graft site. Further, the
plate may include a stepped bore 15 formed about throughbore 14 to
receive the head 17 of the screw 16. See FIG. 6. Therefore, the
above description should not be construed as limiting, but merely
as exemplifications of preferred embodiments. Those skilled in the
art will envision other modifications within the scope and spirit
of the claims appended hereto.
* * * * *