Spinal fusion device with porous material

• US 5,645,598 A
• Filed: 04/15/1996
• Issued: 07/08/1997
• Est. Priority Date: 01/16/1996
• Status: Expired due to Term

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Inventors: Brosnahan, Robert E. III
• Primary Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US08/631,135
• Time in Patent Office: 449 Days
• Field of Search: 623/16, 623/17, 623/18, 606/61
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30733 Inserts placed into an endoprosthetic cavity, e.g. for modifying a material property
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/308 oblong
• CPC Class Codes: A61F 2002/30805 Recesses of comparatively large area with respect to their low depth
• CPC Class Codes: A61F 2002/3082 Grooves
• CPC Class Codes: A61F 2002/3085 with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30858 Threads interrupted by grooves or sidewalls, e.g. flat sidewalls
• CPC Class Codes: A61F 2002/448 comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2230/0019 rectangular
• CPC Class Codes: A61F 2230/0069 cylindrical
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00395 : Coating or prosthesis-covering structure made of metals or of alloys
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

An implant for insertion into at least one bore formed between opposing vertebrae of a spine where the vertebrae are separated by a space and each vertebrae has end plates. The implant is in the shape of a solid generally cylindrical body having a first and a second end, an outer surface, opposing sides and a longitudinal axis. The body has threads on a portion of the outer surface between the first and second ends with the threads being configured for threading into bone. The body includes at least one through slot positioned between the opposing sides, with the through slot containing a biocompatible porous material for allowing the growth of bone through the slot of the body. The through slot is positioned between generally opposing sides of the body so as to provide contact between the biocompatible porous material and the end plates of the opposing vertebrae when the implant is inserted into at least one bore formed between the opposing vertebrae. Depending on the chosen material, the biocompatible porous material may also exhibit characteristics of osteoconductive or osteoinductive materials.

Claims

1. An implant for insertion into at least one bore formed between opposing vertebrae of a spine where the vertebrae are separated by a space and each vertebrae has end plates, the implant comprising:

a) a solid generally cylindrical body having a first and a second end, an outer surface, opposing sides and a longitudinal axis;

b) the body having threads on a portion of the outer surface between the first and second ends, the threads configured for threading into bone;

c) the body including at least one through slot positioned between the opposing sides, the through slot containing a biocompatible porous material for allowing the growth of bone through the slot; and

d) the through slot being positioned between generally opposing sides of the body so as to provide contact between the biocompatible porous material and the end plates of the opposing vertebrae when the implant is inserted into at least one bore formed between the opposing vertebrae.

2. The implant of claim 1, wherein the body includes two generally rectangular through slots.

3. The implant of claim 1, wherein the porous material is selected from a group consisting of biocompatible metallics, ceramics, polymers, and composite materials.

4. The implant of claim 3, wherein the ceramic material is a calcium phosphate.

5. The implant of claim 4, wherein the calcium phosphate is a calcium hydroxylapatite.

6. The implant of claim 1, wherein the biocompatible porous material includes an osteoinductive material such as BMP.

7. The implant of claim 1, wherein two implants are inserted into two bores formed between opposing vertebrae of a spine.

8. The implant of claim 1, wherein the second end of the body has a centrally located internal opening configured to receive a tool receiving and mounting device for securing the body to a tool for inserting the implant into at least one bore formed between opposing vertebrae of a spine.

9. The implant of claim 1, wherein the opposing sides of the body include a top portion on one opposing side and a parallel bottom portion on a second opposing side with two parallel side walls extending between the top and bottom portions, the top and bottom portions and the two parallel side walls being positioned along the longitudinal axis of the body.

10. The implant of claim 9, wherein the top and bottom portions are arcuate in shape conforming to the cylindrical shape of the body and the two side walls are concave in shape along the longitudinal axis of the body.