Method and apparatus for stabilization of facet joint

• US 20040254575A1
• Filed: 06/13/2003
• Published: 12/16/2004
• Est. Priority Date: 06/13/2003
• Status: Active Grant

• Current Assignee: Aeolin, LLC
• Original Assignee: Aeolin, LLC
• Inventors: McKinley, Laurence M., Obenchain, Theodore G.
• Granted Patent: US 7,749,251 B2
• Time in Patent Office: Days
• US Class Current: 606/61
• CPC Class Codes: A61B 17/7064 Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor
• CPC Class Codes: A61B 17/8605 Heads, i.e. proximal ends projecting from bone
• CPC Class Codes: A61B 17/861 specially shaped for gripping driver
• CPC Class Codes: A61B 17/863 with thread interrupted or changing its form along shank, other than constant taper
• CPC Class Codes: A61B 17/8635 Tips of screws
• CPC Class Codes: A61B 17/8863 Apparatus for shaping or cutting osteosynthesis equipment by medical personnel
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 2017/564 Methods for bone or joint treatment
• CPC Class Codes: A61B 2090/037 with a frangible part, e.g. by reduced diameter

Abstract

The current invention is directed to a method, system and apparatus for stabilizing a facet joint. One embodiment of a method according to the current invention includes angling a screw from a ventral and a lateral side of the spine toward a dorsal and medial side of the spine, and screwing the screw through a superior facet of an inferior vertebra and into an inferior facet of a superior vertebra. One embodiment of a system according to the present invention includes a screwdriver insertable into a surgical opening, a screw coupled to the screwdriver and a torque transmitter coupled to and rotatable with a head on the screwdriver. An embodiment of a screwdriver according to the invention includes a handle and a head projecting at an obtuse angle from the handle. The head in this embodiment is coupled to and rotatable with a torque transmitter. An embodiment of a facet screw according to the invention includes a sharp and self-tapping point, an ellipsoidal shaft with progressively spaced threads, and a bulbous screw head. An embodiment of a cutter according to the invention includes a narrow, longitudinal shaft with a two-handle closing mechanism. Another embodiment of a cutter replaces the two-handle closing mechanism with a ratchet mechanism.

Claims

1. A method of stabilizing a superior facet of an inferior vertebra to an inferior facet of a superior vertebra in a spine, the method comprising:

angling the screw from a substantially lateral side of said spine toward a dorsal and medial side of said spine; and

screwing the screw through said superior facet and into said inferior facet.

2. The method of stabilizing according to claim 1, wherein the screwing further comprises directing the screw through said inferior facet and into a spinous process of said superior vertebra.

3. The method of stabilizing according to claim 1, wherein the angling further comprises providing a screwdriver coupled to the screw by an attachment end, and

wherein the screwing further comprises uncoupling the screwdriver to the screw.

4. The method of stabilizing according to claim 3, wherein the uncoupling comprises cutting at least one of the attachment end and the screw.

5. The method of stabilizing according to claim 3, wherein the uncoupling comprises at least one of wriggling and snapping the attachment end away from the screw.

6. The method of stabilizing according to claim 1, further comprising inserting a screw into a patient proximate to said spine through a posterolateral surgical opening.

7. A system for stabilizing a facet joint comprising:

a screwdriver, having a handle coupled to a head, said head projecting from the handle at a first angle and rotatable about a first axis, the screwdriver sized to be insertable into a posterolateral surgical opening;

a screw coupled to the head and rotatable about the first axis in response to a torque applied by the head, the screw sized to be insertable into said facet joint; and

a torque transmitter coupled to the head such that rotation of the torque transmitter about a second axis rotates the head about the first axis.

8. The system for stabilizing according to claim 7, wherein the head has an attachment end, and wherein the screw is formed in one piece with the attachment end.

9. The system for stabilizing according to claim 7, further comprising a cutter with a longitudinal shaft and a first and second cutting edge, the longitudinal shaft configured to reach one of the screw and the head through a surgical opening and sufficiently narrow to allow a view of the screw through the surgical opening.

10. A screwdriver for inserting a screw into a facet joint, the screwdriver comprising:

a handle having a first end and a second end;

a head, having an attachment end, the head coupled to and projecting from the first end of the handle at a first angle and rotatable about a first axis;

a torque transmitter coupled to the head such that rotation of the torque transmitter about a second axis rotates the head about the first axis; and

wherein the attachment end is configured to removably connect to said screw.

11. The system for stabilizing according to claim 10, wherein the torque transmitter is a cable.

12. The system for stabilizing according to claim 11, wherein the cable is braided.

13. The system for stabilizing according to claim 10, wherein the first angle is obtuse.

14. The system for stabilizing according to claim 10, wherein the first angle is approximately 90-120 degrees.

15. The system for stabilizing according to claim 10, wherein the first angle is adjustable.

16. The screwdriver according to claim 10, wherein the attachment end comprises a circumferential wall projecting at the first angle away from the handle, the circumferential wall sized to hold said screw.

17. The screwdriver according to claim 10, wherein the attachment end comprises a clamp sized to hold said screw.

18. The screwdriver according to claim 10, further comprising a dial located on the handle and rotatable about the second axis, the dial fixedly connected to the torque transmitter, such that rotation of the dial rotates the torque transmitter.

19. The screwdriver according to claim 10, further comprising a stationary section coupled between the handle and the head, and wherein the handle is rotatable about the second axis and fixedly connected to the torque transmitter such that rotation of the handle rotates the torque transmitter.

20. The screwdriver according to claim 10, further comprising a motor electrically coupled to the torque transmitter for rotating the torque transmitter about the second axis.

21. A facet screw for fixing a facet joint, comprising:

a screw head portion;

a point portion; and

a shaft portion between the screw head portion and the point portion and integral therewith, the shaft portion having threads which are spaced from each other at a progressively larger distance towards the screw head portion, and

wherein the shaft is substantially elliptical.

22. The facet screw according to claim 21, wherein the point portion is sharp and self-tapping.

23. The facet screw according to claim 21, wherein the screw head portion is substantially bulbous.

24. The facet screw according to claim 21, wherein a total length of the screw head portion, shaft portion, and point portion is approximately 10-14 mm.

25. The facet screw according to claim 21, wherein a diameter of the shaft portion is approximately 2 mm.

26. The facet screw according to claim 21, wherein the screw comprises bioactive material.

27. The facet screw according to claim 21, wherein the screw comprises bioabsorbable material.

28. A cutter for cutting a facet screw away from a facet screwdriver within a surgical opening comprising:

a first handle;

a second handle rotatably connected to the first handle;

a longitudinal shaft extending from the first handle with a diameter sufficiently narrow to allow a view of said facet screw through said surgical opening when the longitudinal shaft is inserted into said surgical opening;

a first cutting edge fixedly coupled to the first handle and projecting from the longitudinal shaft at a first angle; and

a second cutting edge coupled to the second handle and projecting parallel to the first cutting edge such that when the second handle is moved closer to the first handle the second cutting edge approaches a facing edge of the first cutting edge.

29. The cutter according to claim 28, wherein the first angle is substantially orthogonal to the first handle and the longitudinal shaft.

30. The cutter according to claim 28, wherein the at least one of the first cutting edge and the second cutting edge comprises carbide.

31. The cutter according to claim 28, wherein the first handle includes a grip stabilizer.

32. A cutter for cutting a facet screw away from a facet screwdriver within a surgical opening comprising:

a longitudinal shaft, having a first end and a second end, with a diameter sufficiently narrow to allow a view of said facet screw through said surgical opening when the longitudinal shaft is inserted into said surgical opening;

a first cutting edge fixedly coupled to the first end and projecting from the longitudinal shaft at a first angle;

a second cutting edge coupled to the first end and projecting parallel to the first cutting edge; and

a ratchet mechanism, having an activating end proximate to the second end and rotatably coupled to the first and second cutting edges, such that when the activating end is rotated relative to the first and second cutting edges, the second cutting edge approaches a facing edge of the first cutting edge.

33. The cutter according to claim 32, wherein the first angle is substantially orthogonal to the longitudinal shaft.

34. The cutter according to claim 32, wherein the at least one of the first cutting edge and the second cutting edge comprises carbide.