Device for supporting the spinal column

• US 5,129,388 A
• Filed: 10/09/1990
• Issued: 07/14/1992
• Est. Priority Date: 02/09/1989
• Status: Expired due to Term

• Current Assignee: Stryker Corporation
• Original Assignee: Gilles Missenard, Jean-Francois Sacriste, Jean-Louis Vignaud, Philippe Lapresle
• Inventors: Lapresle, Philippe, Missenard, Gilles, Vignaud, Jean-Louis, Sacriste, Jean-Francois
• Primary Examiner(s): Apley, Richard J.
• Assistant Examiner(s): WEINHOFFER, SUSAN
• Application Number:
  US07/582,901
• Time in Patent Office: 644 Days
• Field of Search: 128/69, 606/60-62, 606/72, 411/385, 403/347, 403/362
• US Class Current: 606/258
• CPC Class Codes: A61B 17/7004 with a cross-section which varies along its length A61B17/7019 takes precedence
• CPC Class Codes: A61B 17/7005 Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit in the screw or hook heads
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 17/8695 Washers surrounding screw head in plate hole A61B17/8047, between bone plate and bone A61B17/8028
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2220/0041 using additional screws, bolts, dowels or rivets, e.g. connecting screws

Abstract

A device for supporting a spinal column includes a screw having a U-shaped head, a joining element received within the head, a threaded bolt received within and threadedly engaging the head, and a cap covering an upper portion of the head. The head is internally threaded. The threaded bolt engages the joining element to block relative movement between the joining element and the screw. The cap avoids spreading of the head upon tightening of the bolt in the head.

Claims

1. A device for supporting a spinal column, comprising:

a screw having a U-shaped head, said head being internally threaded;

a joining element received within said head;

an externally threaded bolt received within and threadedly engaging said head, and engaging said joining element to block relative movement between said joining element and said screw; and

a cap covering an upper outer portion of said U-shaped head to avoid spreading of said head upon tightening of said bolt in said head.

2. A device according to claim 1 wherein

said screw comprises external threads having a conicity which differs between a core of said threads and a top of said threads.

3. A device according to claim 1 wherein

said upper portion of said U-shaped head has a generally cylindrical outer surface with upper and lower sections, said upper section having a smaller transverse diameter than said lower section.

4. A device according to claim 1 wherein

said U-shaped head has an internal bottom portion which receives said joining element, said bottom portion being rounded in two planes.

5. A device according to claim 1 wherein

said screw comprises a section connecting said U-shaped head to an externally threaded portion thereof, said section being a concave-shaped quarter circle.

6. A device according to claim 1 wherein

said bolt comprises a conical base;

and

said joining element comprises a series of longitudinally spaced, preformed notches, one of said notches receiving said conical base when said bolt is tightened in said U-shaped head.

7. A device according to claim 3 wherein

said cap comprises a generally cylindrical inner surface mating with said upper section of said outer surface of said U-shaped head to provide a tight sliding connection therebetween.

8. A device according to claim 7 wherein

said cap comprises a top section with a circular orifice for allowing a tool to pass through said cap and to engage said bolt.

9. A device according to claim 8 wherein

said bolt has an upper section with means for receiving and engaging the tool.

10. A device according to claim 1 wherein

said joining element comprises a rod with a cylindrical section and preformed conical notches on a periphery of said rod;

and

said bolt having a base received in one of said notches.

11. A device according to claim 10 wherein

said notches are machines at various pitches for micrometric positioning adjustment of said joining element in said U-shaped head.

12. A device according to claim 1 wherein said joining element is coupled to other devices.

13. A device according to claim 1 wherein

said cap comprises a generally cylindrical, unthreaded inner surface.