[54] APPARATUS FOR SPONDYLOLISTHESIS REDUCTION
[76] Inventor: Madhavan Pisharodi, 942 Wild Rose La., Brownsville, Tex. 78520
[21] Appl. No.: 486,322
[22] Filed: Jun. 7, 1995
Related U.S. Application Data
[63] Continuation of PCT/US95/03347, Mar. 17, 1995 which is a continuation-in-part of Ser. No. 210,229, Mar. 18, 1994.
[51] Int. CI.6 A61B 17/56; A61B 17/58;
A61F 2/30
[52] U.S. CI 606/61; 623/17; 606/90;
606/62
[58] Field of Search 623/17; 606/61,
606/62, 63, 65, 66, 90
[56] References Cited
U.S. PATENT DOCUMENTS
4,714,469 12/1987 Kenna 606/61
4,863,476 9/1989 Shepperd 623/17
5,015,247 5/1991 Michelson 623/17
5,059,193 10/1991 Kuslich 606/60
5,425,773 6/1995 Boyd et al 623/17
5,431,658 7/1995 Moskovich 606/90
5,443,514 8/1995 Steffee 623/17
5,454,365 10/1995 Bonutti 600/204
Primary Examiner—Paul B. Prebilic
Attorney, Agent, or Firm—Mark R. Wisner
An apparatus for reduction of spondylolisthesis involving the insertion of an elongate implant which is split longitudinally into two side-by-side members, one of which is movable relative to the other, into the disk space between two misaligned vertebrae is disclosed. Each of the members is provided with teeth for engaging the adjacent vertebrae and positioned on the members so as to be located on opposite sides of the implant. The implant formed by the two side-by-side members is generally rectangularly-shaped in cross section, the height of the rectangularly-shaped cross section being less than the width so that the implant can be inserted between the adjacent vertebrae with the lesser, height dimension oriented in the same direction as the axis of the spinal column and the larger width dimension at approximately a right angle to that axis. One of the two members is then moved relative to the other from the first position in which the members are in the above-described, side-by-side relationship along the longitudinal axis of the implant to a second position in which the members are aligned with the respective, adjacent, misaligned vertebrae and the implant is then rotated by approximately 90° to cause the teeth to contact the bodies of the adjacent vertebrae. The two members are then brought back into the first side-by-side relationship to draw the misaligned vertebrae into alignment and the implant is rotated approximately 90° to disengage the teeth from the vertebrae for removal of the implant from the disk space.
