Spine microsurgery techniques, training aids and implants

• US 7,452,369 B2
• Filed: 10/18/2004
• Issued: 11/18/2008
• Est. Priority Date: 10/18/2004
• Status: Expired due to Fees

• Current Assignee: Richard J. Barry
• Original Assignee: Richard J. Barry
• Inventors: Barry, Richard J.
• Primary Examiner(s): Robert; Eduardo C.
• Assistant Examiner(s): Rust; Ellen
• Application Number:
  US10/968,860
• Publication Number:
  US 20060085068A1
• Time in Patent Office: 1,492 Days
• Field of Search: 623 1711- 1716, 623/18.11, 606/247, 606/279
• US Class Current: 606/279
• CPC Class Codes: A61B 17/1615 Drill bits, i.e. rotating tools extending from a handpiece to contact the worked material
• CPC Class Codes: A61B 17/1637 Hollow drills or saws producing a curved cut, e.g. cylindrical A61B10/025, A61B17/1695 take precedence
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/7064 Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor
• CPC Class Codes: A61B 17/92 Impactors or extractors, e.g. for removing intramedullary devices insertion or extraction of artificial joints A61F2/4603
• CPC Class Codes: A61B 2090/033 Abutting means, stops, e.g. abutting on tissue or skin
• CPC Class Codes: A61B 2090/3916 Bone tissue
• CPC Class Codes: A61F 2/4405 for apophyseal or facet joints, i.e. between adjacent spinous or transverse processes devices implanted between spinous or transverse processes A61B17/7062
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• 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 2002/30171 rosette- or star-shaped
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/3021 frustoconical
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30769 madreporic
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30884 : Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30968 : Sintering
• CPC Class Codes: A61F 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2230/005 : Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0067 : conical
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: G09B 23/30 : Anatomical models G09B23/281 - G09B23/288 take precedence

Abstract

A minimally invasive, fluoroscopically guided system is disclosed for stabilizing the articular facet joints of adjacent vertebrae. Ring and dowel implants are disclosed for installation into the facet joint. The invention includes a novel spine surgical training aid used in the initial surgeon training process for refreshing the surgeon'"'"'s perspective of the critical three dimensional anatomy of the vertebrae. The invention also includes a surgical kit having a range of size-specific drills, inserters, impactors and custom-length long k-wires matched to the internal diameter of the instrumentation system.

Claims

1. A method for stabilizing adjacent vertebrae of the spine, the adjacent vertebrae comprising superior and inferior articular processes having opposing subchondral articular surfaces to form first and second bilateral posterior facet joints, the method comprising:

forming a bone path into the subchondral bone of the articular surfaces of the first facet joint;

installing an implant axially into the bone path of the first facet joint; and

immobilizing the first facet joint of the articulation between the adjacent vertebrae;

wherein the implant comprises one or more longitudinal ridges that extend at least along a portion of the length of the implant;

wherein, when the implant is being installed into the bone path, the one or more longitudinal ridges create one or more longitudinal grooves that extend radially into the bone of the preformed bone path and axially along the preformed bone path;

wherein, when the implant is installed, the one or more longitudinal ridges are in intimate contact with the longitudinal groove created by it along at least a portion of the length of the bone path to inhibit rotation of the implant within the bone path.

2. A method as recited in claim 1, further comprising:

forming a path into the subchondral bone of the articular surfaces of the second facet joint; and

installing an implant into the bone path of the second facet joint;

wherein the implant is configured to immobilize the second facet joint of the articulation between the adjacent vertebrae.

3. A method as recited in claim 1, wherein forming a path into the subchondral bone comprises:

drilling a cylindrical bore into the subchondral articular surfaces;

wherein a portion of each subchondral articular surface is removed to form grooves defining opposite ends of the cylindrical bore.

4. A method as recited in claim 3, wherein the cylindrical bore is drilled in a path substantially parallel to the planes of the subchondral surfaces.

5. A method as recited in claim 3, wherein the bone is drilled to have a diameter that tapers to a smaller diameter inward into the bore,

wherein installing an implant comprises driving an oversized dowel into the scored bone path to create an interference fit with opposing first and second vertebrae to mechanically lock the articulation of the first facet joint;

and

wherein the oversized dowel has a taper substantially matching the taper of the bone path.

6. A method as recited in claim 5, wherein the implant comprises a roughened surface to promote bony ingrowth into the implant.

7. A method as recited in claim 1, wherein the method is performed percutaneously under fluoroscopic guidance.

8. A method as recited in claim 7, wherein forming a path into the subchondral bone comprises:

visualizing the planes of the subchondral surfaces of the facet joint;

determining the size of the path into the subchondral bone according to said visualization of the facet joint;

installing a blunt dilator down to an outer surface of the facet joint; and

drilling a cylindrical bore into the opposing articular processes, the blunt dilator guiding the path of the cylindrical bore.

9. A method as recited in claim 8, wherein drilling a cylindrical bore comprises advancing a hollow-core drill having an inside diameter closely matching the outside diameter of the dilator over the dilator to score kerfs into the opposing articular processes.

10. A method as recited in claim 9, wherein installing an implant comprises driving a ring implant into the cylindrical kerfs formed in the articular processes;

the ring implant constraining motion of the facet joint through circumferential tension band effect.

11. A method as recited in claim 9, wherein the dilator is configured to limit the depth of the bored bone path.

12. A method as recited in claim 11, wherein the bone path is drilled to a depth corresponding to approximately 75% of the facet joint bone mass.

13. A method as recited in claim 8, wherein visualizing the planes of the subchondral surfaces of the facet joint is done fluoroscopically.

14. A method as recited in claim 13, wherein determining the size of the bone path comprises positioning a radiolucent implant guide at the facet joint and comparing the implant guide against bone mass of the articular processes.

15. A method as recited in claim 14, further comprising installing a guide wire into the facet joint.

16. A method as recited in claim 15, wherein the blunt dilator is positioned at the facet joint by advancing it over the guide wire.

17. A method as recited in claim 15, wherein a radiolucent implant guide is positioned at the facet joint to measure the size of the bone path.

18. A method as recited in claim 1, wherein the bore is drilled from a dorsal aspect of the facet joint.

19. A method as recited in claim 1, wherein the bore is drilled from a dorsal aspect of the facet joint toward a ventral aspect of the facet joint.

20. A method as recited in claim 1, wherein the one or more longitudinal ridges are installed substantially perpendicular to the rotational moment created by the facet joint physiologic stress.

21. A method as recited in claim 1, wherein the one or more longitudinal ridges engage the bone path at a location at least along the distal half of the bone path.

22. A method as recited in claim 1:

wherein the implant comprises a plurality of longitudinal fenestrations disposed substantially parallel to the one or more longitudinal ridges;

wherein the longitudinal fenestrations promote bony ingrowth from the bone path radially inward into the implant to fuse the facet joint.

23. A method for stabilizing adjacent vertebrae of the spine, the adjacent vertebrae comprising superior and inferior articular processes having opposing subchondral articular surfaces to form first and second bilateral posterior facet joints, the method comprising:

forming a bone path into the subchondral bone of the articular surfaces of the first facet joint;

guiding an implant axially into the bone path of the first facet joint;

the implant having a diameter correlating to a diameter of the bone path such that the implant creates an interference fit with the bone path when installed in the bone path;

wherein the implant comprises one or more longitudinal ridges that extend axially at least along a portion of the length of the implant;

the one or more longitudinal ridges extending radially from the diameter of the implant such that the one or more longitudinal ridges extend radially into the bone of the bone path as the implant is guided into the path;

wherein, when installed, the one or more longitudinal ridges are in intimate contact with bone surrounding the one or more longitudinal ridges for at least a portion of the length of the bone path to inhibit rotation of the implant within the bone path; and

immobilizing the first facet joint of the articulation between the adjacent vertebrae against translational and rotational forces imposed on the first facet joint.

24. A method as recited in claim 23, further comprising:

promoting bony ingrowth radially into the implant from the bored bone path to fuse the first facet joint.

25. A method as recited in claim 23, wherein the one or more longitudinal ridges are positioned on the implant such that the implant is guided axially into the bone path without rotation of the implant with respect to the bone path.