US5697929A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-limiting set screw for use with spinal implant systems
Assignee: EBI LLC
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Filing: 1995-10-18
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Granted: 1997-12-16
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Expires: 2015-10-18
Abstract
Abstract The invention relates to a set screw having a self-limiting external torque head. The head has a hexagonal external cross-section and an internal bore which extends through a necked portion. The necked portion joins the external torque head to the threaded screw portion of the set screw. The necked portion has a cross-sectional thickness and strength to provide for shearing at a predetermined load limit, such as from about 54 to about 64 pounds per inch. The threaded screw portion has an internal hex to allow for the internal application of loosening torque at about two-thirds of the tightening torque limit, i.e., to provide a loosening torque of about 40 inch-pounds. The screw member includes a high-compression, rod-contacting surface such as a knurled surface.
Inventors
- 👤 Phillip A. Mellinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:23
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/68; A61B17/70; A61B17/7001; A61B90/00; A61B90/03; A61B2090/037
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
64 words
A spinal implant set screw comprising a torque head having at least one planar external surface for the external application of torque to said set screw, said planar external surface being parallel to the longitudinal axis of said set screw, and said torque head joined by a torque-limiting area to a screw member having an external threaded area which has an internal torque opening.
Claim 2
Dependent Claim
64 words
A spinal implant set screw comprising a torque head having at least one planar external surface for the external application of torque to said set screw, said planar external surface being parallel to the longitudinal axis of said set screw, and said torque head joined by a torque-limiting area to a screw member having an external threaded area which has an internal torque opening.
Claim 3
Dependent Claim
19 words
A spinal implant set screw as set forth in claim 1, wherein said torque-limiting area comprises a necked portion.
Claim 4
Dependent Claim
20 words
A spinal implant set screw as set forth in claim 1, wherein said torque-limiting area further includes an internal opening.
Claim 5
Dependent Claim
20 words
A spinal implant set screw as set forth in claim 1, wherein said torque-limiting area has a reduced cross-sectional area.
Claim 6
Dependent Claim
20 words
A spinal implant set screw as set forth in claim 1, wherein said internal torque opening comprises a hexagonal opening.
Claim 7
Dependent Claim
19 words
A spinal implant set screw as set forth in claim 4, wherein said screw member has a high-compression surface.
Claim 8
Dependent Claim
19 words
A spinal implant set screw as set forth in claim 6, wherein said high-compression surface is a knurled surface.
Claim 9
Dependent Claim
26 words
A spinal implant set screw as set forth in claim 7, wherein said screw member has a bevel and a lateral surface with said knurled surface.
Claim 10
Dependent Claim
24 words
A spinal implant set screw as set forth in claim 8, wherein said external torque head comprises a head having an external hexagonal cross-section.
Claim 11
Dependent Claim
91 words
An orthopedic set screw having a torque head having at least one external planar surface for the external application of torque, said external planar surface being parallel to the longitudinal axis of said set screw, and said torque head joined by a torque-limiting area to a screw member having external threads, said torque-limiting area being an area of reduced external diameter and including a central opening, said screw member including an torque applicator opening adjacent said central opening and internal to said external threads and including an external, high-compression, rod-contacting surface.
Claim 12
Dependent Claim
91 words
An orthopedic set screw having a torque head having at least one external planar surface for the external application of torque, said external planar surface being parallel to the longitudinal axis of said set screw, and said torque head joined by a torque-limiting area to a screw member having external threads, said torque-limiting area being an area of reduced external diameter and including a central opening, said screw member including an torque applicator opening adjacent said central opening and internal to said external threads and including an external, high-compression, rod-contacting surface.
Claim 13
Dependent Claim
16 words
An orthopedic set screw as set forth in claim 10, which comprises a biocompatible, surgical-grade metal.
Claim 14
Dependent Claim
46 words
An orthopedic set screw as set forth in claim 11, wherein said applicator head shears at said torque-limiting area at a torque of from about 54 to about 64 inch-pounds and said internal torque applicator area allows a loosening torque of up to about 50 inch-pounds.
Claim 15
Dependent Claim
31 words
Am orthopedic set screw as set forth in claim 12, wherein said torque applicator head has an external cross-sectional hexagonal shape and said torque applicator opening has an internal hexagon cross-section.
Claim 16
Dependent Claim
47 words
A surgical screw having a longitudinal axis and a first threaded portion having a knurled terminal surface, and an axially aligned second portion with a hexagonal-shaped external configuration, said screw having an opening along said longitudinal axis which is hexagonal-shaped in at least said first threaded portion.
Claim 17
Dependent Claim
47 words
A surgical screw having a longitudinal axis and a first threaded portion having a knurled terminal surface, and an axially aligned second portion with a hexagonal-shaped external configuration, said screw having an opening along said longitudinal axis which is hexagonal-shaped in at least said first threaded portion.
Claim 18
Dependent Claim
132 words
A spinal implant system, comprising; a rod; an anchor which cooperates with said rod and having a threaded bore; and a set screw having a longitudinal axis and which is received in said threaded bore to secure said rod relative to said anchor and comprising a hexagonal shaped torque head having a first diameter joined by a torque-limiting area to a screw member having external threads of a second diameter, said torque-limiting area having a third diameter which is smaller than the first diameter and smaller than the second diameter and the first and second diameter may be the same or different and the torque-limiting area having a central opening, said screw member including a hexagonal shaped torque applicator opening joined to said central opening and internal to said externally threaded area.
Claim 19
Dependent Claim
132 words
A spinal implant system, comprising; a rod; an anchor which cooperates with said rod and having a threaded bore; and a set screw having a longitudinal axis and which is received in said threaded bore to secure said rod relative to said anchor and comprising a hexagonal shaped torque head having a first diameter joined by a torque-limiting area to a screw member having external threads of a second diameter, said torque-limiting area having a third diameter which is smaller than the first diameter and smaller than the second diameter and the first and second diameter may be the same or different and the torque-limiting area having a central opening, said screw member including a hexagonal shaped torque applicator opening joined to said central opening and internal to said externally threaded area.
Claim 20
Dependent Claim
120 words
A spinal implant system, comprising: a rod; an anchor which cooperates with said rod and has a threaded bore; and a set screw which is received in said threaded bore to secure said rod relative to said anchor, said set screw having a longitudinal axis and having along said axis a torque head, a torque-limiting area, and an externally threaded area which includes a terminal high compression rod-contacting surface, said torque-limiting area having a smaller external diameter than said torque head, and said torque head extending axially outward relative to said threaded bore, said set screw further comprising an internal torque opening extending along said longitudinal axis through said torque head and said torque-limiting area into said externally threaded area.
Claim 21
Dependent Claim
120 words
A spinal implant system, comprising: a rod; an anchor which cooperates with said rod and has a threaded bore; and a set screw which is received in said threaded bore to secure said rod relative to said anchor, said set screw having a longitudinal axis and having along said axis a torque head, a torque-limiting area, and an externally threaded area which includes a terminal high compression rod-contacting surface, said torque-limiting area having a smaller external diameter than said torque head, and said torque head extending axially outward relative to said threaded bore, said set screw further comprising an internal torque opening extending along said longitudinal axis through said torque head and said torque-limiting area into said externally threaded area.
Claim 22
Dependent Claim
17 words
A spinal implant system according to claim 16, wherein said torque head is an external torque head.
Claim 23
Dependent Claim
21 words
A spinal implant system according to claim 17, wherein said external torque head comprises a head having an external hexagonal cross-section.
Claim 24
Dependent Claim
17 words
A spinal implant system according to claim 16, wherein said internal torque opening comprises a hexagonal opening.
Claim 25
Dependent Claim
14 words
A spinal implant system according to claim 16, which comprises a biocompatible, surgical-grade metal.
Claim 26
Dependent Claim
14 words
A spinal implant system according to claim 20, which comprises a biocompatible, surgical-grade metal.
References Cited (Backward Citations)
US791548A
Cited
GB203508A
Cited
US2201087A
Cited
US2239352A
Cited
US2295314A
Cited
US2532815A
Cited
US2553337A
Cited
US2778265A
Cited
US2877681A
Cited
US2927332A
Cited
US3115804A
Cited
US3143029A
Cited
US3812757A
Cited
FR2467312A1
Cited
US4506917A
Cited
US4492500A
Cited
US4763644A
Cited
US4764068A
Cited
DE3738409A1
Cited
US5005562A
Cited
US5129388A
Cited
US5073074A
Cited
US5364400A
Cited
US5382248A
Cited
US5282707A
Cited
US5499892A
Cited
US5507747A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-15 | 2001-06-16 | 2001-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-15 | 2005-06-16 | 2005-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-15 | 2009-06-16 | 2009-12-16 | $7700.00 | Window Closed / Lapsed |