Open backed pedicle screw

• US 4,887,596 A
• Filed: 03/02/1988
• Issued: 12/19/1989
• Est. Priority Date: 03/02/1988
• Status: Expired due to Term

• Current Assignee: Synthes GmbH (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Sherman, Michael
• Primary Examiner(s): Johnson, Richard J.
• Assistant Examiner(s): Sam, Charles H.
• Application Number:
  US07/163,278
• Time in Patent Office: 657 Days
• Field of Search: 47/92 YM, 47/69, 47/92 YL, 47/92 R, 47/92 ZZ, 47/92 ZW, 403/234-237, 403/362
• US Class Current: 606/305
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 2017/603 with three points of contact, e.g. tripod
• CPC Class Codes: F16B 2/065 using screw-thread elements F16B2/08 - F16B2/12 take precedence
• CPC Class Codes: F16B 7/048 for rods or for tubes without using the innerside thereof

Abstract

A pedicle screw for use in internal fixation of the spine comprising a shaft threaded at one end for insertion into a bone and, at the other end, having a yoke for receiving a rod, said yoke having a cusp adapted to bear against the rod and means for clamping the rod against the cusp, while permitting adjustment of the angle between said rod and said yoke.

Claims

1. A pedicle screw comprising a shaft having a forward end, a rear end and a longitudinal axis, said forward end being threaded for insertion into a bone and said rear end having a yoke attached thereto, the interior wall of said yoke nearest the shaft having a projection comprising two tapered walls forming an edge, said edge of said projection being adapted to bear against a rod inserted into the yoke, and means in said yoke for clamping a rod inserted in said yoke against said edge.

2. The pedicle screw claimed in claim 1 and comprising a block, means for slidingly mounting said block in said yoke and means on said block for clamping a rod inserted in the yoke at a variety of angles to the longitudinal axis of the shaft.

3. The pedicle screw claimed in claim 1 and comprising grooves in the sides of said yoke, a block having lands matching the grooves in the sides of the yoke for slidingly mounting the block in the yoke and screw means in the block for pressing a rod inserted in the yoke against the edge of the projection.

4. The pedicle screw claimed in claim 3 wherein the screw means comprises two set screws, adapted to bear against said rod on opposite sides of the edge of the projection.

5. The pedicle screw claimed in claim 3 wherein the grooves in the yoke and the lands in the block have undercut portions which dovetail with one another.

6. The pedicle screw claimed in claim 3 and comprising means in said undercut portions for suppressing relative movement between said block and said yoke.

7. A pedicle screw comprising a shaft and clamping means on said shaft for clamping said shaft to a rod running transversely to the axis of the shaft, said clamping means comprising a yoke on an end of said shaft, an interior wall of said yoke having inwardly extending fulcrum means for contacting a rod inserted in said yoke, a panel removably mounted in said yoke, and means in said panel for pressing a rod inserted in said yoke against said fulcrum means.

8. The pedicle screw claimed in claim 7 wherein said panel has screws adapted to be advanced into said yoke on either side said fulcrum means, for tilting a rod inserted in the yoke relative to the axis of the shaft.