Systems and methods for fixation of adjacent vertebrae

• US 6,793,656 B1
• Filed: 03/06/2000
• Issued: 09/21/2004
• Est. Priority Date: 03/17/1992
• Status: Expired due to Fees

• Current Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: Mathews, Hallett H.
• Primary Examiner(s): Woo, Julian W.
• Application Number:
  US09/519,295
• Time in Patent Office: 1,660 Days
• Field of Search: 606/61, 606/191, 606/96, 606/99, 606/104, 600/208, 600/233, 600/566, 600/567
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/70 Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
• CPC Class Codes: A61B 17/7007 Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit around the screw or hook heads
• CPC Class Codes: A61B 17/7049 Connectors, not bearing on the vertebrae, for linking longitudinal elements together A61B17/7055, A61B17/7053, A61B17/7019 take precedence
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• 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 2/4455 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 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 2002/2839 Bone plugs or bone graft dowels
• CPC Class Codes: A61F 2002/30329 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• 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 2002/449 comprising multiple spinal implants located in different intervertebral spaces or in different vertebrae
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements

Abstract

A method for internal fixation of vertebra of the spine to facilitate graft fusion includes steps for excising the nucleus of an affected disc, preparing a bone graft, instrumenting the vertebrae for fixation, and introducing the bone graft into the resected nuclear space. Disc resection is conducted through two portals through the annulus, with one portal supporting resection instruments and the other supporting a viewing device. The fixation hardware is inserted through small incisions aligned with each pedicle to be instrumented. The hardware includes bone screws, fixation plates, engagement nuts, and linking members. In an important aspect of the method, the fixation plates, engagement nuts and linking members are supported suprafascially but subcutaneously so that the fascia and muscle tissue are not damaged. The bone screw is configured to support the fixation hardware above the fascia. In a further aspect of the invention, a three component dilator system is provided for use during the bone screw implantation steps of the method.

Claims

1. A minimally invasive surgical method for fixing adiacent vertebrae, comprising:

sequentially dilating tissue with a number of dilators, of which an outer dilator provides an access portal to a disc space between the adjacent vertebrae; and

fusing the adjacent vertebrae with material introduced through the sequentially dilated portal, wherein sequentially dilating the skin and tissue includes placing at least three dilator tubes of increasing inner bore diameter one over the other and withdrawing the inner dilator tubes to provide the access portal to the disc space through the last inserted dilator tube.

2. The method of claim 1, further comprising performing a discectomy through the access portal before fusing the adjacent vertebrae.

3. The method of claim 1, further comprising securing fixation instrumentation to the adjacent vertebrae.

4. The method of claim 3, wherein the fixation instrumentation is secured to the pedicles of the adjacent vertebrae.

5. The method of claim 1, further comprising:

sequentially dilating skin and tissue to provide a second access portal to a disc space between the adjacent vertebrae; and

visualizing the disc space through the second access portal.

6. The method of claim 1, wherein the material includes bone graft material.

7. The method of claim 6, further comprising:

sequentially dilating skin and tissue to provide a second access portal to a disc space between the adjacent vertebrae; and

visualizing the delivery of bone graft material to the disc space through the access portal with a viewing instrument in the second access portal.

8. A minimally invasive surgical system for fusing adjacent vertebrae, comprising:

at least three tissue dilators each including a bore therethrough, said bores being of increasing diameter wherein said at least three tissue dilators are positionable one over the other to sequentially dilate tissue to provide access through tissue to at least one of the adjacent vertebrae;

at least one bone screw engageable to each of the adjacent vertebrae; and

an elongated fixation element extendable between the adjacent vertebrae when implanted and engageable to each bone screw engaged to the adjacent vertebrae.

9. The system of claim 8, further comprising a guide wire for guiding placement of the at least three tissue dilators.

10. The system of claim 8, further comprising bone graft material positionable in a spinal disc space between the adjacent vertebrae.

11. The system of claim 8, wherein the elongated fixation element is a plate.

12. A three component dilator system for use in implantation of a bone screw into a vertebra, comprising:

a first tubular dilator having a tapered end, a first length and a first diameter;

a second tubular dilator having a tapered end, a second length and a second diameter;

a third tubular dilator having a tapered end, a third length and a third diameter;

a bone screw, wherein said first diameter is sized to receive said bone screw therethrough; and

wherein said first length is shorter than said second length which is shorter than said third length.

13. The three component dilator system of claim 12, wherein:

said second tubular dilator has a second end opposite said tapered end, said second dilator having a knurled outer surface adjacent said second end; and

said third tubular dilator has a second end opposite said tapered end, said third dilator having a knurled outer surface adjacent said second end.

14. The system of claim 12, wherein said first diameter is at least 5.5 millimeters.

15. A minimally invasive surgical method for fixing adjacent vertebrae, comprising:

sequentially dilating skin and tissue to provide an access portal to a disc space between the adjacent vertebrae; and

fusing the adjacent vertebrae with material introduced through the sequentially dilated portal; and

securing fixation instrumentation to pedicles of the adjacent vertebrae.

16. The method of claim 15, comprising performing a discectomy through the access portal before fusing the adjacent vertebrae.

17. The method of claim 15, further comprising:

sequentially dilating skin and tissue to provide a second access portal to a disc space between the adjacent vertebrae; and

visualizing the disc space through the second access portal.

18. The method of claim 15, wherein the material includes bone graft material.

19. The method of claim 18, further comprising:

sequentially dilating skin and tissue to provide a second access portal to a disc space between the adjacent vertebrae; and

visualizing the delivery of bone graft material to the disc space through the access portal with a viewing instrument in the second access portal.

20. The method of claim 15, wherein sequentially dilating the skin and tissue includes placing at least three dilator tubes of increasing inner bore diameter one over the other and withdrawing the inner dilator tubes to provide the access portal to the disc space through the last inserted dilator tube.

21. A minimally invasive surgical system for fusing adjacent vertebrae, comprising:

at least three tissue dilators each including a bore therethrough, said bores being of increasing diameter wherein said at least three tissue dilators are positionable one over the other to sequentially dilate tissue and provide an access portal through tissue to a disc space between adjacent vertebrae; and

bone graft material deliverable through the access portal to the disc space between the adjacent vertebrae.

22. The system of claim 21, further comprising:

at least one bone screw engageable to each of the adjacent vertebrae; and

an elongated fixation element extendable between the adjacent vertebrae when implanted and engageable to each bone screw engaged to the adjacent vertebrae.

23. The system of claim 22, wherein the elongated fixation element is a plate.

24. The system of claim 21, further comprising a guide wire for guiding placement of the at least three tissue dilators.