CA1328957C
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Functional and biocompatible intervertebral disc spacer containing elastomeric material of varying hardness
Assignee: Rutgers, The State University of New Jersey
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Filing: 1989-08-17
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Granted: 1994-05-03
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Expires: 2009-08-17
Abstract
Abstract ABSTRACT The construction and manufacturing technique for a functional biocompatible intervertebral disc spacer is described. This device is useful for a replacement for a degenerated disc in certain treatments of back pain and spinal disease. The disc spacer possesses mechanical properties akin to those of the normal disc and will preserve normal functions of the spinal motion segment. The device achieves the desired properties by varying the hardness of the elastomeric material in its nucleus and annulus. The present invention relates to a biocompatible intervertebral spacer comprising: a central core of a soft biocompatible elastomeric material shaped and sized so as to approximate the shape and size of a nucleus pulposus of a natural intervertebral disc; an outer ring of stiffer elastomeric material surrounding said central core to approximate the size and shape of a natural annulus fibrosus; and endplates comprised of a stiff biocompatible material and affixed, one to each end, to the outer ring central core.
Inventors
- 👤 Casey K. Lee
- 👤 Alastair J. Clemow
- 👤 John R. Parsons
- 👤 Elizabeth H. Chen
- 👤 Noshir A. Langrana
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-10-27 21:22
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/44; A61F2/442; A61F2/30721; A61F2/30724; A61F2/30767; A61F2002/30001; A61F2002/30003; A61F2002/30004; A61F2002/30016; A61F2002/3006; A61F2002/30065; A61F2002/30069; A61F2002/30108; A61F2002/3011; A61F2002/30112; A61F2002/30133; A61F2002/30316; A61F2002/30535; A61F2002/30563; A61F2/3094; A61F2002/30968; A61F2210/00; A61F2210/0071; A61F2230/00; A61F2230/0002; A61F2230/0004; A61F2230/0015; A61F2250/00; A61F2250/0014; A61F2250/0019; A61F2310/00; A61F2310/00389; A61F2310/00395; A61F2310/00407; A61F2310/00592; A61F2310/00796; A61F2310/00952
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
95 words
A biocompatible intervertebral spacer comprising: a central core of an unreinforced soft biocompatible elastomeric material shaped and sized so as to approximate the shape and size of a nucleus pulposus of a natural intervertebral disc; an outer ring of stiff elastomeric material surrounding said central core to approximate the size and shape of a natural annulus fibrosus, said outer ring and said central core forming a disc having upper and lower surfaces; and endplates comprised of a stiff biocompatible material and affixed to each end of said upper and lower surfaces with additional elastomeric material.
Claim 2
Dependent Claim
95 words
A biocompatible intervertebral spacer comprising: a central core of an unreinforced soft biocompatible elastomeric material shaped and sized so as to approximate the shape and size of a nucleus pulposus of a natural intervertebral disc; an outer ring of stiff elastomeric material surrounding said central core to approximate the size and shape of a natural annulus fibrosus, said outer ring and said central core forming a disc having upper and lower surfaces; and endplates comprised of a stiff biocompatible material and affixed to each end of said upper and lower surfaces with additional elastomeric material.
Claim 3
Dependent Claim
16 words
A spacer according to Claim 1 wherein the biocompatible elastomer utilized is a thermoplastic polyurethane elastomer.
Claim 4
Dependent Claim
20 words
A spacer according to Claim 1 wherein the biocompatible elastomer utilized is the elastomer sold under the trademark C-Flex ?.
Claim 5
Dependent Claim
11 words
A spacer according to Claim 1 wherein the endplates contain hydroxylapatite.
Claim 6
Dependent Claim
24 words
A spacer according to Claim 1 wherein the outer ring surrounding said central core contains 1-5 layers of a biocompatible elastomer of varying hardness.
Claim 7
Dependent Claim
16 words
A spacer according to Claim 5 wherein the biocompatible elastomer utilized is a thermoplastic polyurethane elastomer.
Claim 8
Dependent Claim
20 words
A spacer according to Claim 5 wherein the biocompatible elastomer utilized is the elastomer sold under the trademark C-Flex ?.
Claim 9
Dependent Claim
11 words
A spacer according to Claim 5 wherein the endplates contain hydroxylapatite.
Claim 10
Dependent Claim
24 words
A spacer according to Claim 1 wherein the outer ring surrounding said central core contains 2-3 layers of a biocompatible elastomer of varying hardness.
Claim 11
Dependent Claim
16 words
A spacer according to Claim 9 wherein the biocompatible elastomer utilized is a thermoplastic polyurethane elastomer.
Claim 12
Dependent Claim
16 words
A spacer according to Claim 9 wherein the biocompatible elastomer utilized is the elastomer C-Flex ?.
Claim 13
Dependent Claim
11 words
A spacer according to Claim 9 wherein the endplates contain hydroxylapatite.
Claim 14
Dependent Claim
21 words
A spacer according to Claim 1 wherein the central core contains 1-5 layers of a biocompatible elastomeric material of varying hardness.
Claim 15
Dependent Claim
16 words
A spacer according to Claim 13 wherein the biocompatible elastomer utilized is a thermoplastic polyurethane elastomer.
Claim 16
Dependent Claim
15 words
A spacer according to Claim 13 wherein the biocompatible elastomer utilized is the elastomer C-Flex?.
Claim 17
Dependent Claim
11 words
A spacer according to Claim 13 wherein the endplates contain hydroxylapatite.
Claim 18
Dependent Claim
11 words
A spacer according to Claim 1 wherein the endplates are metal.
Claim 19
Dependent Claim
17 words
A spacer according to Claim 1 wherein the endplates have a porous metallic or polymeric sintered surface.
Claim 20
Dependent Claim
17 words
A spacer according to Claim 1 wherein the endplates provide for a mechanical interlock with adjacent bones.
Claim 21
Dependent Claim
17 words
A spacer according to Claim 1 wherein the endplates are fashioned for use with polymethylmethacrylate bone cement.
Claim 22
Dependent Claim
17 words
A spacer according to Claim 1 sized so as to approximate the size of a natural disc.
Claim 23
Dependent Claim
20 words
A spacer according to Claim 1 sized so as to approximate the 30-80% of the size of a natural disc.
Claim 24
Independent Claim
161 words
A method for preparing a biocompatible intervertebral spacer, said spacer comprising a central core of an unreinforced soft biocompatible elastomeric material shaped and sized so as to approximate the shape and size of a nucleus pulposus of a natural intervertebral disc, an outer ring of stiff elastomeric material surrounding said central core to approximate the size and shape of a natural annulus fibrosus, said outer ring and said central core forming a disc having upper and lower surfaces; and endplates comprised of suitably stiff biocompatible material and affixed to each end of said upper and lower surfaces with additional elastomeric material; wherein said method comprises: forming said central core by injection, transfer or compression molding; molding said outer ring around central core, in a stepwise fashion, if more than one later of elastomer is used, said outer ring and said central core forming a disc having upper and lower surfaces; and applying said endplates to said molded upper and lower surfaces.
Claim 25
Independent Claim
161 words
A method for preparing a biocompatible intervertebral spacer, said spacer comprising a central core of an unreinforced soft biocompatible elastomeric material shaped and sized so as to approximate the shape and size of a nucleus pulposus of a natural intervertebral disc, an outer ring of stiff elastomeric material surrounding said central core to approximate the size and shape of a natural annulus fibrosus, said outer ring and said central core forming a disc having upper and lower surfaces; and endplates comprised of suitably stiff biocompatible material and affixed to each end of said upper and lower surfaces with additional elastomeric material; wherein said method comprises: forming said central core by injection, transfer or compression molding; molding said outer ring around central core, in a stepwise fashion, if more than one later of elastomer is used, said outer ring and said central core forming a disc having upper and lower surfaces; and applying said endplates to said molded upper and lower surfaces.
Claim 26
Dependent Claim
23 words
A method according to Claim 23 wherein the central core and outer ring are formed from the elastomer sold under the trademark C-Flex?.
Claim 27
Dependent Claim
38 words
A method according to Claim 23 wherein the endplates are applied to the disc formed by the outer ring and central core by molding the endplates directly onto said disc formed by the outer ring and central core.
Claim 28
Dependent Claim
28 words
A method according to Claim 23 wherein the endplates are metal and are applied to the disc formed by the outer ring and central core using additional elastomer.
Claim 29
Dependent Claim
20 words
A method according to Claim 23 wherein the endplates are additionally coated with a layer of hydroxylapatite or polymeric material.
Claim 30
Dependent Claim
111 words
Use of a biocompatible intervertebral spacer for alleviating the pain and/or paralysis of a damaged or diseased disc, said spacer comprising; a central core of a unreinforced soft biocompatible elastomeric material shaped and sized so as to approximate the shape and size of a nucleus pulposus of a natural intervertebral disc; an outer ring of stiff elastomeric material surrounding said central core to approximate the size and shape of a natural annulus fibrosus, said outer ring and said central core forming a disc having upper and lower surfaces; and endplates comprised of a stiff biocompatible material and affixed to each end of said upper and lower surfaces with additional elastomeric material.
Claim 31
Dependent Claim
111 words
Use of a biocompatible intervertebral spacer for alleviating the pain and/or paralysis of a damaged or diseased disc, said spacer comprising; a central core of a unreinforced soft biocompatible elastomeric material shaped and sized so as to approximate the shape and size of a nucleus pulposus of a natural intervertebral disc; an outer ring of stiff elastomeric material surrounding said central core to approximate the size and shape of a natural annulus fibrosus, said outer ring and said central core forming a disc having upper and lower surfaces; and endplates comprised of a stiff biocompatible material and affixed to each end of said upper and lower surfaces with additional elastomeric material.
Claim 32
Dependent Claim
25 words
Use according to Claim 28 wherein the central core and outer ring of the disc spacer are comprised of elastomer sold under the trademark C-Flex?.
Claim 33
Dependent Claim
11 words
Use according to Claim 28 wherein the spacer contains metal endplates.
Claim 34
Dependent Claim
13 words
Use according to Claim 28 wherein the spacer contains endplates of elastomeric material.
Claim 35
Dependent Claim
10 words
Use according to Claim 28 wherein the endplates contain hydroxylapatite.
Claim 36
Dependent Claim
133 words
An implantable biocompatible intervertebral spacer comprised of: (a) a central core having tip, bottom and side surfaces, and which is comprised of an unreinforced biocompatible elastomeric material having a stiffness which approximates the stiffness of the nucleus pulposus of a natural intervertebral disc; (b) an outer ring annularly surrounding the central core, having upper, lower and side surfaces, and which is comprised of an unreinforced biocompatible elastomeric material having the stiffness which approximates the stiffness of an annulus fibrosus of a natural intervertebral disc, said outer ring and said central core forming a disc having upper and lower surfaces; and (c) upper and lower endplates which are comprised of a biocompatible, stiff material affixed to at least one of the upper and lower surfaces of the central core and the outer ring, respectively.
Claim 37
Dependent Claim
133 words
An implantable biocompatible intervertebral spacer comprised of: (a) a central core having tip, bottom and side surfaces, and which is comprised of an unreinforced biocompatible elastomeric material having a stiffness which approximates the stiffness of the nucleus pulposus of a natural intervertebral disc; (b) an outer ring annularly surrounding the central core, having upper, lower and side surfaces, and which is comprised of an unreinforced biocompatible elastomeric material having the stiffness which approximates the stiffness of an annulus fibrosus of a natural intervertebral disc, said outer ring and said central core forming a disc having upper and lower surfaces; and (c) upper and lower endplates which are comprised of a biocompatible, stiff material affixed to at least one of the upper and lower surfaces of the central core and the outer ring, respectively.
Claim 38
Dependent Claim
91 words
The implantable biocompatible intervertebral spacer of Claim 33 wherein the endplates consist essentially of an upper endplate and a lower endplate, the upper endplate having a top and a bottom surface, the bottom surface being attached to at least one of the upper surface of the central core and the upper surface of the outer ring, and the lower endplate having a top and bottom surface, the top surface being attached to at least one of the lower surface of the central core and the lower surface of the outer ring.
Claim 39
Dependent Claim
53 words
The implantable biocompatible intervertebral spacer of Claim 34 wherein at least one of the upper endplate top surface and the lower endplate bottom surface is porous or is coated with hydroxylapatite in an amount sufficient to facilitate the attachment of the spacer to an adjacent bony vertebral body during replacement surgery or use.
Claim 40
Dependent Claim
34 words
An implantable biocompatible intervertebral spacer in accordance with Claim 34 wherein the mean axial stiffness of the spacer is about 1000-3500 newtons/mm and the mean torsional stiffness of the spacer is about 0.8-3.0 Nm/degree.
Claim 41
Dependent Claim
125 words
In an implantable, biocompatible, intervertebral spacer which is comprised of (a) a central core comprised of an unreinforced biocompatible elastomeric material having the softness of a natural nucleus pulposus, (b) an outer ring which annularly surrounds the central core and which is comprised of an unreinforced biocompatible elastomeric material having the stiffness of a natural annulus fibrosus, and (c) upper and lower endplates each comprised of a biocompatible, stiff material affixed to at least one of the upper and lower surfaces of the central core and outer ring, the improvement comprising utilizing an unreinforced material as the central core and annular outer ring which provides the spacer with a mean axial stiffness of about 1000-3000 newtons/mm and a mean torsional stiffness of about 0.8-3.0 Nm/degree.
Claim 42
Dependent Claim
125 words
In an implantable, biocompatible, intervertebral spacer which is comprised of (a) a central core comprised of an unreinforced biocompatible elastomeric material having the softness of a natural nucleus pulposus, (b) an outer ring which annularly surrounds the central core and which is comprised of an unreinforced biocompatible elastomeric material having the stiffness of a natural annulus fibrosus, and (c) upper and lower endplates each comprised of a biocompatible, stiff material affixed to at least one of the upper and lower surfaces of the central core and outer ring, the improvement comprising utilizing an unreinforced material as the central core and annular outer ring which provides the spacer with a mean axial stiffness of about 1000-3000 newtons/mm and a mean torsional stiffness of about 0.8-3.0 Nm/degree.
References Cited (Backward Citations)
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