Locking spiral anchoring system

Patent metadata

Field	Value
Publication number	US-9642662-B2
Application number	US-75274810-A
Country	US
Kind code	B2
Filing date	Apr 1, 2010
Priority date	Apr 2, 2009
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A bone fixation screw comprises a proximal head being configured to lockingly engage a bone plate hole and a substantially helical shaft extending distally from the head along a substantially helical path. The head and the shaft are rotatably coupled to each other so that the shaft can rotate about a central longitudinal axis thereof with respect to the head.

First claim

What is claimed is:

1. A bone screw, comprising:
a proximal head being configured to lockingly engage a bone plate hole; and
a substantially helical shaft extending distally from the head along a substantially helical path,
wherein the head and the shaft are rotatably coupled to each other so that the shaft can rotate about a central longitudinal axis thereof with respect to the head and wherein the head is rotatably coupled to a circular coupling attached to the shaft.

2. The bone screw according to claim 1 , wherein the head includes a driver engaging structure in the form of a recess formed thereon.

3. The bone screw according to claim 1 , wherein the head comprises an external thread having a pitch P 1 for lockingly engage the bone plate hole, and wherein the shaft is formed in a helical shape having the pitch P 2 .

4. The bone screw according to claim 3 , wherein the pitch P 2 of the shaft is greater than the pitch P 1 of the external thread and wherein the ratio P 2 /P 1 is larger than 7.

5. The bone screw according to claim 4 , wherein the ratio P 2 /P 1 , is larger than 10.

6. The bone screw according to claim 3 , wherein the external thread is a multiple thread.

7. The bone screw according to claim 3 , wherein the external thread is a double thread.

8. The bone screw according to claim 1 , wherein the circular coupling includes a tab extending radially therefrom to engage a respectively sized portion of the bone plate hole.

9. The bone screw according to claim 1 , wherein the circular coupling includes a driver engaging structure formed thereon.

10. The bone screw according to claim 1 , wherein the head and the shaft are coupled to each other in an axially fixed manner.

11. The bone screw according to claim 1 , wherein a coupling between the head and the shaft permits an axial relative movement between 0.5 mm. and 3.0 mm.

12. The bone screw according to claim 1 , wherein the head has a helical through bore configured to slidingly receive the shaft therein.

13. The bone screw according to claim 1 , wherein a cross-sectional shape of the shaft is one of circular, oval, triangular, rectangular and hexagonal.

14. The bone screw according to claim 1 , wherein the shaft has the form of a helically wound thin rod.

15. A bone screw, comprising:
a proximal head being configured to lockingly engage a bone plate hole; and
a substantially helical shaft extending distally from the head along a substantially helical path,
wherein the head and the shaft are rotatably coupled to each other so that the shaft can rotate about a central longitudinal axis thereof with respect to the head and wherein a distal portion of the shaft has a rigidity less than that of a proximal portion thereof to facilitate bending during insertion.

16. The bone screw according to claim 15 , wherein the shaft comprises a notch located in a distal portion.

17. A bone screw, comprising:
a proximal head being configured to lockingly engage a bone plate hole; and
a substantially helical shaft extending distally from head along a substantially helical path,
wherein the head and the shaft are rotatably coupled to each other so that the shaft can rotate about a central longitudinal axis thereof with respect to the head and wherein the head tapers conically towards the shaft at an angle between 2.8° and 20°.

Assignees

• Appenzeller Andreas
• Frigg Robert
• Overes Tom
• Bouduban Nicolas
• Depuy Synthes Products Inc

Inventors

• Appenzeller Andreas
• Frigg Robert
• Overes Tom
• Bouduban Nicolas

Classifications

• A61B17/8685

  comprising multiple separate parts · CPC title

• A61B17/869 Primary

  characterised by an open form, e.g. wire helix · CPC title

• A61B17/8057

  the interlocking form comprising a thread · CPC title

• A61B17/80

  Cortical plates {, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates} · CPC title

• F16B25/00

  Screws that cut thread in the body into which they are screwed, e.g. wood screws {(F16B35/065 takes precedence; joining sheets or plates using screws with two separate threads F16B5/0275, using screws with adjustment sleeves F16B5/0283)} · CPC title