MINIMAL INCISION REMOVABLE BONE SCREW

• US 20170071646A1
• Filed: 11/03/2016
• Published: 03/16/2017
• Est. Priority Date: 07/20/2011
• Status: Active Grant

• Current Assignee: Michael H. Horwitz
• Original Assignee: Michael H. Horwitz
• Inventors: Horwitz, Michael H.
• Granted Patent: US 10,441,334 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 17/862 at the periphery of the screw head
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 17/863 with thread interrupted or changing its form along shank, other than constant taper
• CPC Class Codes: A61B 17/864 hollow, e.g. with socket or cannulated
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 17/8883 the driver bit acting on the periphery of the screw head
• CPC Class Codes: A61B 2017/8655 with special features for locking in the bone
• CPC Class Codes: F04C 2270/0421 Controlled or regulated

Abstract

A surgical bone screw (1) and driver (31), and a method for using them for repairing an osteotomy or fracture. The screw has a shaft having a head (5) at its proximal end, screw threads (3) at its distal end and a compression member (7) between the head and the screw threads. In an embodiment, the threads are self-tapping and self-drilling, the head is polygonal, and the sides of the polygon are convex. The driver turns the screw until the threads cross a fracture site and the compression member contacts the proximal bone fragment. The threads and compression member draw the fragments together and leaves the head entirely clear of the bone surface. The screw is removed through a small incision. Tilting the driver to allow the socket to engage an inwardly extending lower portion of the head permits the driver to lift the screw out of the bone.

Claims

1. A bone screw for repairing an osteotomy or fracture by lag compression, the bone screw comprising:

a shaft having a proximal end and a distal end;

a head at the proximal end of the shaft, the head having a proximal end;

a screw thread at the distal end of the shaft;

an enlarged bone-engaging convex compression surface disposed on the shaft between the proximal end of the head and the screw thread, characterized in that

the head and the compression surface are formed to be smooth with no sharp edges, a distance between the proximal end of the head and a distal end of the compression surface being at least twice a major diameter of the screw thread,

and in that the head and the compression member are configured for placement of the head below the skin of a patient when the screw is inserted across the osteotomy or fracture.

2. The bone screw of claim 1 wherein the enlarged surface is a distal portion of the head.

3. The bone screw of claim 1 wherein the head has an axially extending socket at its proximal end.

4. The bone screw of claim 3 wherein the socket is polygonal.

5. The bone screw of claim 1 wherein a proximal end of the head is polygonal.

6. The bone screw of claim 1 wherein the screw is cannulated.

7. A bone screw made of a biocompatible material, the bone screw being sized and shaped to fix bone fragments of an osteotomy or fracture of a bone by screwing into a distal fragment and engaging a proximal fragment with a compression surface on the screw, the head and the compression member being configured for placement of the head below the skin of a patient, the screw further being configured to be removed after bone healing has progressed, the bone screw comprising:

a thread at a distal end of the screw, the thread having a major diameter and a minor diameter;

a head at a proximal end of the screw;

a bone-engaging compression surface spaced distally from a proximal end of the head, the bone-engaging compression member being convex on a distal side and circular in cross-section, and having a smooth outline without edges to permit easy insertion and extraction through an incision, the compression surface having a maximum diameter from 10% to 70% greater than the major diameter of the thread,

a distance from the proximal end of the head to the distal end of the compression surface being from two to six times the major diameter of the thread.

8. The bone screw of claim 7 wherein the enlarged surface is a distal portion of the head.

9. The bone screw of claim 7 wherein the head has an axially extending socket at its proximal end.

10. The bone screw of claim 9 wherein the socket is polygonal.

11. The bone screw of claim 7 wherein a proximal end of the head is polygonal.

12. The bone screw of claim 7 wherein the screw is cannulated.