Intervertebral implant for transforaminal posterior lumbar interbody fusion procedure

• US 20020165612A1
• Filed: 05/03/2001
• Published: 11/07/2002
• Est. Priority Date: 05/03/2001
• Status: Active Grant

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson), Synthes AG Chur
• Inventors: Gerber, David, Messerli, Dominique, Paul, David
• Granted Patent: US 6,719,794 B2
• Time in Patent Office: Days
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1659 Surgical rasps, files, planes, or scrapers
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30383 made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove
• CPC Class Codes: A61F 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/30594 slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30797 internally-threaded
• CPC Class Codes: A61F 2002/30843 Pyramidally-shaped
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30975 : made of two halves
• CPC Class Codes: A61F 2002/4628 : with linear motion along or rotating motion about an axis transverse to the instrument axis or to the implantation direction, e.g. clamping
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0098 : radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00359 : Bone or bony tissue

Abstract

An intervertebral implant for fusing vertebrae is disclosed. The implant has a body with curved, substantially parallel posterior and anterior faces separated by two narrow implant ends, superior and inferior faces having a plurality of undulating surfaces for contacting upper and lower vertebral endplates, and at least one depression at a first end for engagement by an insertion tool. The arcuate implant configuration facilitates insertion of the implant from a transforaminal approach into a symmetric position about the midline of the spine so that a single implant provides balanced support to the spinal column. The implant may be formed of a plurality of interconnecting bodies assembled to form a single unit. An implantation kit and method are also disclosed.

Claims

1. An intervertebral implant comprising:

a body having

curved, substantially parallel posterior and anterior faces separated by two narrow implant ends; and

superior and inferior faces for contacting upper and lower vertebral endplates,

wherein the arcuate implant configuration facilitates insertion of the implant via a transforaminal window.

2. The implant of claim 1, further comprising a plurality of undulating surfaces on the superior and inferior faces.

3. The implant of claim 2, further comprising means for engagement by an insertion tool.

4. The implant of claim 3, wherein the superior and inferior faces are convex.

5. The implant of claim 4, wherein the thickness of the implant between the superior and inferior faces is greatest at a mid-section between the narrow ends of the implant and the thickness tapers toward the narrow ends.

6. The implant of claim 5, wherein at least one of the narrow ends is rounded.

7. The implant of claim 5, wherein at least one of the narrow ends is substantially straight.

8. The implant of claim 2, wherein the undulating surfaces are teeth.

9. The implant of claim 3, wherein the engagement means is at least one depression in the anterior or posterior face for engagement by an insertion tool.

10. The implant of claim 1, wherein the implant is formed of a plurality of interconnecting bodies assembled to form a single unit.

11. The implant of claim 11, further comprising at least one pin extending through an opening in the plurality of bodies to hold the bodies together as a single unit.

12. The implant of claim 11, wherein the plurality of bodies have mating interlocking surfaces that aid in holding the bodies together as a single unit.

14. The kit of claim 13, further comprising an angled impactor for properly positioning the implant within the affected disc space.

15. The kit of claim 13, wherein the insertion tool is angled to facilitate proper positioning of the implant within the affected disc space.

16. The kit of claim 13, further comprising at least one angled curette for removing disc material from the affected disc space.

17. The kit of claim 13, further comprising at least one trial-fit spacer for estimating the size of the implant to be inserted into the affected disc space.

18. The kit of claim 13, further comprising a guide to assist in positioning the implant behind the dura wherein the guide has a curved arm designed and configured to cooperate with the curved anterior face of the implant to facilitate proper positioning of the implant about the midline of the spine behind the dura.

20. The method of claim 19, further comprising positioning the implant symmetrically about the midline of the spine.

21. The method of claim 19, wherein the insertion tool is angled to facilitate insertion of the implant via the transforaminal window.

22. The method of claim 21, further comprising impacting the implant with an impactor tool to properly position the implant within the affected disc space.

23. The method of claim 22, wherein the impactor tool is angled to facilitate proper positioning of the implant within the affected disc space.

25. The method of claim 19, wherein the inserting and guiding steps comprise first inserting the narrow end of the implant into the transforaminal window, rotating the implant so that the anterior face of the implant faces anteriorly and moving the implant around the dura.

13. A kit for implanting an intervertebral implant into an affected disc space of a patient via a transforaminal window comprising:

an implant having a body with curved, substantially parallel posterior and anterior faces separated by two narrow implant ends, superior and inferior faces having a plurality of undulating surfaces for contacting upper and lower vertebral endplates, and at least one depression at a first end for engagement by an insertion tool; and

an insertion tool for holding the implant during insertion,

wherein the arcuate implant configuration facilitates insertion of the implant via the transforaminal window.

19. A method for implanting an intervertebral implant into an affected disc space of a patient comprising:

creating a transforaminal window from the posterior side of the spine;

inserting bone graft material into the affected disc space;

providing an implant having a body with curved, substantially parallel posterior and anterior faces separated by two narrow implant ends, superior and inferior faces having a plurality of undulating surfaces for contacting upper and lower vertebral endplates;

inserting the implant into the affected disc space via the transforaminal window with an insertion tool;

guiding the implant around the dura through the transforaminal window using the insertion tool.

24. The method of claim of 19, further comprising using a curved guide to assist in locating the implant in the affected disc space behind the dura.

26. An intravertebral implant for maintaining a desired space between vertebral bodies comprising:

a solid body having

a convex anterior face, the anterior face shaped to match the shape of the anterior perimeter of the vertebrae;

a concave posterior face;

arcuate convex end faces connected between the posterior and anterior faces, the posterior and anterior faces being at least double the length of the end faces and the posterior and anterior faces each having at least one channel extending from one of the end faces toward the other end face configured and adapted to be engageable with an insertion tool; and

superior and inferior faces for contacting upper and lower vertebral end plates, the superior and inferior faces having teeth,

wherein the implant is configured and adapted to be inserted into the disc space through a transforaminal window formed in the posterior of the spinal column and positioned behind the dura between vertebral end plates to maintain balanced support about the midline of the spine.