System and method for bone fixation

• US 6,730,092 B2
• Filed: 12/03/2001
• Issued: 05/04/2004
• Est. Priority Date: 12/03/2001
• Status: Expired due to Fees

• Current Assignee: Pioneer Surgical Technology Incorporated (Surgalign Holdings, Inc.)
• Original Assignee: Pioneer Laboratories Incorporated
• Inventors: Songer, Matthew N.
• Primary Examiner(s): Milano, Michael J.
• Assistant Examiner(s): DAVIS, DANIEL J
• Application Number:
  US10/007,146
• Publication Number:
  US 20030105459A1
• Time in Patent Office: 883 Days
• Field of Search: 606/60, 606/61, 606/72, 606/73, 606/74, 606/103, 606/232
• US Class Current: 606/308
• CPC Class Codes: A61B 17/0401 Suture anchors, buttons or pledgets, i.e. means for attaching sutures to bone, cartilage or soft tissue; Instruments for applying or removing suture anchors A61B17/0642 takes precedence; fixation devices for tendons or ligaments A61F2/0811
• CPC Class Codes: A61B 17/0469 Suturing instruments for use in minimally invasive surgery, e.g. endoscopic surgery
• CPC Class Codes: A61B 17/0487 Suture clamps, clips or locks, e.g. for replacing suture knots; Instruments for applying or removing suture clamps, clips or locks suture anchors A61B17/0401; wound clamps or clips A61B17/08; ligaturing clamps or clips A61B17/122
• CPC Class Codes: A61B 17/7022 Tethers, i.e. longitudinal elements capable of transmitting tension only, e.g. straps, sutures or cables A61B17/702 takes precedence
• CPC Class Codes: A61B 17/864 hollow, e.g. with socket or cannulated
• CPC Class Codes: A61B 2017/0409 Instruments for applying suture anchors for applying suture clamps, clips or locks A61B2017/0488
• CPC Class Codes: A61B 2017/0414 having a suture-receiving opening, e.g. lateral opening lateral eyelet for attaching suture to needle A61B2017/06019
• CPC Class Codes: A61B 2017/044 with a threaded shaft, e.g. screws
• CPC Class Codes: A61B 2017/0445 cannulated, e.g. with a longitudinal through-hole for passage of an instrument
• CPC Class Codes: A61B 2017/0454 the anchor being crimped or clamped on the suture
• CPC Class Codes: A61B 2017/0488 Instruments for applying suture clamps, clips or locks for applying suture anchors A61B2017/0409; for applying wound clamps A61B17/10; for applying ligaturing clamps or clips A61B17/128
• CPC Class Codes: A61B 2017/0496 for tensioning sutures
• CPC Class Codes: A61B 2017/7073 with intervertebral connecting element crossing an imaginary spinal median surface
• CPC Class Codes: Y10S 606/90 Lumbar stabilizer
• CPC Class Codes: Y10S 606/907 Composed of particular material or coated

Abstract

A system and method for maintaining positions of bones fixed or approximated relative to each other is provided that is ideal for minimizing interference with surrounding viscera in spinal column procedures, although other good application therefor are also disclosed. In the preferred form, a cable anchoring apparatus in the form of a screw member having an elongate shank that is threaded for substantially the full length thereof is employed. An internal driver surface is provided so that the size of the proximate end of the shank can be minimized or maintained consistently sized with respect to the reminder of the shank with no enlarged driver head formed thereat. This allows the amount of bone material that is removed from full insertion of the screw anchor to be minimized, i.e. no countersinking for an enlarged driver head is necessary, thus improving holding power of the cable anchor herein. Further, the full threading of the shank for substantially its entire length enables the screw member to be fully sunk into the bone so that no portions thereof, such as an enlarged screw head, project into the surrounding body cavity in which the bone is located. In the spinal column application, a criss-cross cable pattern is disclosed to better resist torsional forces and keep any decompression devices in place in the gap between adjacent vertebrae.

Claims

1. A cable anchoring apparatus comprising:

a screw member for being inserted into a bone portion and having a central axis thereof,

a shank wall of the screw member having spaced proximal distal ends and an axial bore extending therethrough;

a flexible cable having an enlarged end portion that secures the cable against being pulled through the bore;

a small diameter intermediate section of the bore through which the cable extends and sized smaller than the cable enlarged end portion;

a larger diameter section of the bore at the distal end of the shank wall in which the cable enlarged end portion is held; and

an elongate tapering portion of the bore intermediate section that gradually tapers radially outwardly relative to the central axis as the tapering portion extends toward the proximal end of the shank wall to allow the cable to engage along the tapering portion to begin to flex in a direction offset from the screw axis prior to being bent about the shank wall proximal end as the cable exits the bore;

wherein the axial bore includes an enlarged driver section at the proximate end of the shank immediately adjacent to the tapering portion.

2. A The cable anchoring apparatus of claim 1 wherein the shank wall has a predetermined number of external threads each having substantially the same major and minor diameters, and the shank wall has wall portions that vary in thickness with a maximum thickness wall portion extending along the small diameter bore section and having a majority of the threads formed thereon for maximizing screw strength and holding power.

3. The cable anchoring apparatus of claim 1 wherein the cable is of a metallic material.

4. The cable anchoring apparatus of claim 1 wherein the elongate bore tapering portion includes a gradually tapering bore surface that tapers by approximately seven degrees from the screw central axis.

5. The cable anchoring apparatus of claim 1 wherein the shank wall has external threads formed thereon with the proximate end of the wall being free of a screw head or thread to keep size of the shank wall proximate end to a minimum.

6. The cable anchoring apparatus of claim 1 wherein the bore includes a shoulder surface extending generally normal to the screw axis between the small and larger diameter bore sections, and the cable enlarged end portion includes a radially extending abutment surface for engaging flush against the shoulder surface.