US6280475B1
Expired / Lapsed
US
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Hydrogel intervertebral disc nucleus implantation method
Assignee: Howmedica Osteonics Corp
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Filing: 1999-09-02
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Granted: 2001-08-28
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Expires: 2019-09-02
Abstract
Abstract An article for use in the preparation of a hydrogel prosthetic nucleus, for an intervertebral disc, having equilibrium water contents (EWCs) of from about 30 to about 90% and compressive strengths of at least 4 meganewtons per square meter (MNm −2 ), at their EWCs, when subjected to the same constraints as the normal nucleus, comprising one or more xerogel rods containing from zero to less than the EWC. A method for preparing a hydrogel prosthetic nucleus, for a vertebral disc, comprising one or more hydrogel rods containing from about 30 to about 90% water, and having compressive strengths of at least 1 MNmn −2 , at their EWCs, which comprises inserting one or more hydrophilic xerogel rods, which at their EWC will contain from about 30 to about 90% water and have compressive strengths of at least 1 MNm −2 , containing water in an amount from about zero to less than their EWC, into the cavity of the disc through an opening in its annulus and allowing the rod, or rods, to absorb sufficient water from the body fluids to attain their EWCs and essentially fill the intervertebral nuclear disc cavity.
Inventors
- 👤 Qi-Bin Bao
- 👤 Paul A. Higham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:53
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/44; A61F2/442; A61F2/441; A61F2002/30001; A61F2002/30108; A61F2002/30199; A61F2002/30291; A61F2002/30298; A61F2002/4435; A61F2002/444; A61F2230/00; A61F2230/0063; A61F2230/0091; Y; Y10; Y10S; Y10S623/00; Y10S623/902; Y10S623/908
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
88 words
A method of treating a intervertebral disc comprising: (a) providing an elongate, partially hydrated hydrogel member having a cross-sectional diameter of between about 2 mm and about 10 mm; (b) inserting at least part of the member into a cavity within an intervertebral disc to only partially fill the cavity wherein the member folds upon itself a plurality of times during insertion and; (c) allowing the part of the member within the cavity to increase in hydration and essentially fill and conform to the shape of the cavity.
Claim 2
Independent Claim
88 words
A method of treating a intervertebral disc comprising: (a) providing an elongate, partially hydrated hydrogel member having a cross-sectional diameter of between about 2 mm and about 10 mm; (b) inserting at least part of the member into a cavity within an intervertebral disc to only partially fill the cavity wherein the member folds upon itself a plurality of times during insertion and; (c) allowing the part of the member within the cavity to increase in hydration and essentially fill and conform to the shape of the cavity.
Claim 3
Independent Claim
97 words
A method for implanting a hydrophilic xerogel rod into a cavity in an intervertebral disc, which cavity is formed by the removal of the natural nucleus, the cavity surrounded by the natural annulus of the intervertebral disc, comprising: forming an opening in the annulus from an outer surface thereof into the cavity; inserting one hydrophilic xerogel rod of a sufficient length and cross-section such that once inside the cavity the rod may fold over itself a plurality of times so that the hydrogel, upon expansion to its equilibrium water content either fills or almost fills the cavity.
Claim 4
Independent Claim
97 words
A method for implanting a hydrophilic xerogel rod into a cavity in an intervertebral disc, which cavity is formed by the removal of the natural nucleus, the cavity surrounded by the natural annulus of the intervertebral disc, comprising: forming an opening in the annulus from an outer surface thereof into the cavity; inserting one hydrophilic xerogel rod of a sufficient length and cross-section such that once inside the cavity the rod may fold over itself a plurality of times so that the hydrogel, upon expansion to its equilibrium water content either fills or almost fills the cavity.
Claim 5
Independent Claim
124 words
A method for implanting a hydrophilic xerogel rod into a cavity in an intervertebral disc, which cavity is formed by the removal of the natural nucleus, the cavity surrounded by the natural annulus of the intervertebral disc, comprising: forming an opening in the annulus from an outer surface thereof into the cavity; inserting at least one hydrophilic xerogel rod of sufficient length and cross-section such that once inside the cavity the rod may fold over itself a plurality of times and upon expansion to its equilibrium water content, almost completely fills the cavity wherein the xerogel is prepared by crystallizing a solution of PVA at a temperature of −10° C. or below, said solution comprising a solvent comprising a mixture of DMSO and water.
Claim 6
Independent Claim
124 words
A method for implanting a hydrophilic xerogel rod into a cavity in an intervertebral disc, which cavity is formed by the removal of the natural nucleus, the cavity surrounded by the natural annulus of the intervertebral disc, comprising: forming an opening in the annulus from an outer surface thereof into the cavity; inserting at least one hydrophilic xerogel rod of sufficient length and cross-section such that once inside the cavity the rod may fold over itself a plurality of times and upon expansion to its equilibrium water content, almost completely fills the cavity wherein the xerogel is prepared by crystallizing a solution of PVA at a temperature of −10° C. or below, said solution comprising a solvent comprising a mixture of DMSO and water.
Claim 7
Dependent Claim
20 words
The method of claim 2 wherein the equilibrium water content of the xerogel is from about 30 to about 90%.
Claim 8
Dependent Claim
17 words
The method of claim 4 wherein the equilibrium water content is from about 70 to about 85%.
Claim 9
Dependent Claim
43 words
The method of claim 2 wherein the cross-sectional area of the opening formed in the annulus, connecting the outside thereof with the nucleus cavity of the disc, has a cross-section approximately equal to or slightly greater than the cross-section of the xerogel rod.
Claim 10
Dependent Claim
20 words
The method of claim 6 wherein the diameter of the xerogel rod is from about 2 to about 10 mm.
Claim 11
Dependent Claim
20 words
The method of claim 7 wherein the diameter of the xerogel rod is from about 4 to about 8 mm.
Claim 12
Dependent Claim
23 words
The method of claim 2 wherein the xerogel is used in the form of a hydrogel comprising less than its equilibrium water content.
Claim 13
Dependent Claim
34 words
The method of claim 9 wherein the opening in the annulus is equal to or larger than the cross-section of the rod to allow the xerogel rod to pass therethrough and into the cavity.
Claim 14
Dependent Claim
20 words
The method of claim 10 wherein the diameter of the hydrogel rod is from about 2 to about 10 mm.
Claim 15
Dependent Claim
20 words
The method of claim 11 wherein the diameter of the hydrogel rod is from about 4 to about 8 mm.
Claim 16
Dependent Claim
35 words
The method of claim 2 wherein the xerogel at said equilibrium water content compressive strength of at least 1 MNm −2 when subjected to the constraints of the annulus and end plates of the disc.
Claim 17
Dependent Claim
20 words
The prosthetic nucleus of claim 13 wherein the xerogel has a compressive strength of at least 4 MNm −2 .
Claim 18
Dependent Claim
18 words
The method of claim 1 wherein the cavity is created by the complete removal of a natural nucleus.
Claim 19
Dependent Claim
21 words
The method of claim 1 wherein the cavity is created by the removal of only a portion of a natural nucleus.
Claim 20
Dependent Claim
17 words
The method as set forth in claim 2 wherein the rod folds over itself in spiral fashion.
Claim 21
Dependent Claim
18 words
The method of claim 3 wherein the cavity is created by the complete removal of a natural nucleus.
Claim 22
Dependent Claim
21 words
The method of claim 3 wherein the cavity is created by the removal of only a portion of a natural nucleus.
Claim 23
Dependent Claim
16 words
The method of claim 2 wherein said water is absorbed from body fluids in the cavity.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2004-08-27 | 2005-02-26 | 2005-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-08-27 | 2009-02-26 | 2009-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-08-27 | 2013-02-26 | 2013-08-28 | $7700.00 | Window Closed / Lapsed |