US5650485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-oxidizing polymeric medical implant
Assignee: Howmedica Osteonics Corp
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Filing: 1995-05-11
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Granted: 1997-07-22
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Expires: 2015-05-11
Abstract
Abstract A medical implant made of polymeric material having an increased oxidation resistance is formed by a method including the steps of placing a resin powder in a sealed container. A substantial portion of the oxygen is removed from the sealed container by either a vacuum, an oxygen absorbent or by flushing with inert gas. The container is then repressurized with a gas such as nitrogen, argon, helium or neon so that long term storage may be possible. On use, the resin is transferred to a forming device which both melts and forms the resin in an oxygen reduced atmosphere to produce a polymeric raw material such as a rod or bar stock. The medical implant is then formed from this raw material annealed and sealed in an air-tight package in an oxygen reduced atmosphere. The implant is then radiation sterilized and thereafter annealed in the package for a predetermined time and temperature sufficient to form cross-links between any free radicals in neighboring polymeric chains.
Inventors
- 👤 Deh-Chuan Sun
- 👤 Casper F. Stark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:35
CPC Classifications
A; A61; A61L; A61L2/00; A61L2/02; A61L2/08; A61L2/081; A61L15/00; A61L15/16; A61L15/42; A61L15/60; A61L2/082; A61L2/087; A61L27/00; A61L27/14; A61L27/16; A61L29/00; A61L29/04; A61L29/041; A61L31/00; A61L31/04; A61L31/048; B; B29; B29C; B29C35/00; B29C35/02; B29C35/08; B29C35/0805; B29C2035/085; B29C43/00; B29C43/02; B29C43/16; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/0658; B29K2023/0683; B29K2105/00; B29K2105/25; B29K2105/253; B29K2995/00; B29K2995/0037; B29K2995/0087; B29K2995/0089; B29L; B29L2031/00; B29L2031/753; B29L2031/7532; Y; Y10; Y10S; Y10S522/00; Y10S522/915; Y10S525/00; Y10S525/937; Y10S623/00; Y10S623/901
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
181 words
A method for producing a medical implant from a plastic resin powder, the implant having improved oxidation resistance comprising the steps of: placing the resin in a sealed container; removing a substantial portion of the oxygen from said sealed container such that the atmosphere therein has no more than 1% oxygen; repressurizing the sealed container with a gas selected from the group consisting of nitrogen, argon, helium and neon and a combination thereof; then transferring said resin to a forming device which both melts and forms said resin in an oxygen reduced atmosphere to produce a polymeric raw material; thereafter annealing the raw material for at least about four hours at a temperature between 25° C. and the melting point of said polymeric raw material; forming the implant from the polymeric raw material; sealing the formed implant in a package in an atmosphere having no more than 1% oxygen; radiation sterilizing said packaged implant; and heating said packaged implant for at least about four hours at a temperature of between 25° C. and the melting point of said polymeric raw material.
Claim 2
Independent Claim
181 words
A method for producing a medical implant from a plastic resin powder, the implant having improved oxidation resistance comprising the steps of: placing the resin in a sealed container; removing a substantial portion of the oxygen from said sealed container such that the atmosphere therein has no more than 1% oxygen; repressurizing the sealed container with a gas selected from the group consisting of nitrogen, argon, helium and neon and a combination thereof; then transferring said resin to a forming device which both melts and forms said resin in an oxygen reduced atmosphere to produce a polymeric raw material; thereafter annealing the raw material for at least about four hours at a temperature between 25° C. and the melting point of said polymeric raw material; forming the implant from the polymeric raw material; sealing the formed implant in a package in an atmosphere having no more than 1% oxygen; radiation sterilizing said packaged implant; and heating said packaged implant for at least about four hours at a temperature of between 25° C. and the melting point of said polymeric raw material.
Claim 3
Dependent Claim
48 words
The method for producing a raw material as set forth in claim 1 wherein said removal of said oxygen from said container is a method selected from the group consisting of applying a vacuum, flushing with an inert gas and using an oxygen absorbent and a combination thereof.
Claim 4
Dependent Claim
44 words
The method for producing a raw material as set forth in claim 1 wherein said annealing step takes place at a temperature between about 37° C. and about 135° C. for at least four hours in an atmosphere having no more than 1% oxygen.
Claim 5
Independent Claim
138 words
A method for producing a medical implant from a plastic resin powder, the implant having improved oxidation resistance, comprising the steps of: placing the resin in a container; removing a substantial portion of the oxygen from the container such that the atmosphere therein has no more than 1% oxygen by replacing the air therein with a gas selected from the group consisting of nitrogen, argon, helium and neon and a combination thereof; then transferring said resin into a forming device which melts and forms said resin in an atmosphere having no more than 1% oxygen to produce a polymeric raw material; and thereafter annealing the raw material for at least about four hours at a temperature of between 25° C. and the melting point of said polymeric ray material in an atmosphere having no more than 1% oxygen.
Claim 6
Independent Claim
138 words
A method for producing a medical implant from a plastic resin powder, the implant having improved oxidation resistance, comprising the steps of: placing the resin in a container; removing a substantial portion of the oxygen from the container such that the atmosphere therein has no more than 1% oxygen by replacing the air therein with a gas selected from the group consisting of nitrogen, argon, helium and neon and a combination thereof; then transferring said resin into a forming device which melts and forms said resin in an atmosphere having no more than 1% oxygen to produce a polymeric raw material; and thereafter annealing the raw material for at least about four hours at a temperature of between 25° C. and the melting point of said polymeric ray material in an atmosphere having no more than 1% oxygen.
Claim 7
Dependent Claim
38 words
The method for producing a medical implant as set forth in claim 4 wherein said annealing step takes place at a temperature between about 37° C. and about 135° C. for at least four hours in said atmosphere.
Claim 8
Independent Claim
192 words
A method for producing a medical implant from a plastic resin powder, the implant having improved oxidation resistance comprising the steps of: placing the resin in a container; removing a substantial portion of the oxygen from the container so that the atmosphere therein has no more than 1% oxygen by replacing the air therein with a gas selected from the group consisting of nitrogen, argon, helium and neon and a combination thereof; then transferring said resin to a forming device which both melts and forms said resin in an atmosphere having no more than 1% oxygen to produce a polymeric raw material; thereafter annealing the raw material for at least about four hours at a temperature of between 25° C. and the melting point of said polymeric raw material in an atmosphere having no more than 1% oxygen; forming the implant from the polymeric raw material; sealing the formed implant in a package in an atmosphere having no more than 1% oxygen; radiation sterilizing said packaged implant; and heating said packaged implant for at least four hours at a temperature between 25° C. and the melting point of said polymeric raw material.
Claim 9
Independent Claim
192 words
A method for producing a medical implant from a plastic resin powder, the implant having improved oxidation resistance comprising the steps of: placing the resin in a container; removing a substantial portion of the oxygen from the container so that the atmosphere therein has no more than 1% oxygen by replacing the air therein with a gas selected from the group consisting of nitrogen, argon, helium and neon and a combination thereof; then transferring said resin to a forming device which both melts and forms said resin in an atmosphere having no more than 1% oxygen to produce a polymeric raw material; thereafter annealing the raw material for at least about four hours at a temperature of between 25° C. and the melting point of said polymeric raw material in an atmosphere having no more than 1% oxygen; forming the implant from the polymeric raw material; sealing the formed implant in a package in an atmosphere having no more than 1% oxygen; radiation sterilizing said packaged implant; and heating said packaged implant for at least four hours at a temperature between 25° C. and the melting point of said polymeric raw material.
Claim 10
Dependent Claim
38 words
The method for producing a medical implant as set forth in claim 6 wherein said annealing step takes place at a temperature between about 37° C. and about 135° C. for at least four hours in said atmosphere.
Claim 11
Dependent Claim
30 words
The method as set forth in claim 6 wherein said heating step is performed at a temperature of between about 37° C. and 135° C. for at least four hours.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-21 | 2001-01-20 | 2001-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-21 | 2005-01-20 | 2005-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-21 | 2009-01-20 | 2009-07-22 | $7700.00 | Window Closed / Lapsed |