Snap-off screw with recessed breakoff area

Abstract

A snap-off screw (10) for insertion into one or more two bone regions (12A) (12B) includes a screw body (14) having a screw region (16) and a driver region (18). Upon insertion of the screw region (16), the driver region (18) is designed to be decoupled from the screw region (16). The screw region (16) includes a screw distal end (224), an opposed screw proximal end (226), a threaded area (228), and a head area (232) positioned at the screw proximal end (226). The driver region (18) includes a driver attachment end (238) and an opposed driver distal end (240). The driver attachment end (238) is coupled to the screw region (16) between the screw distal end (224) and the screw proximal end (226). With this design, when the driver region (18) is decoupled from the screw region (16), a screw break surface (460) is positioned below a portion of the head area (232) of the screw region (16). As a result thereof, the screw break surface (460) does not provide an area of irritation for soft tissue around the inserted snap-off screw (10).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

FIG. 1 is a simplified side illustration of a pair of bone regions, in cut-away, that are fused together with a portion of a snap-off screw having features of the present invention;

FIG. 2A is a side view of a first embodiment of a snap-off screw having features of the present invention;

FIG. 2B is an end view of the snap-off screw of FIG. 2A;

FIG. 3A is a cut-away view taken on line 3A-3A of FIG. 2B;

FIG. 3B is an enlarged detail view taken from FIG. 3A;

FIG. 3C is an enlarged detail view taken from FIG. 3A; and

FIG. 4 is a cut-away view of a portion of the snap-off screw in a broken configuration.

Claims

1. A snap-off screw for screwing into a bone region, the snap-off screw comprising: a screw body including (i) a screw region having a screw distal end, an opposed screw proximal end, a threaded area, and a head area positioned at the screw proximal end, and (ii) a driver region having a driver attachment end and an opposed driver distal end, the driver attachment end being coupled to the screw region between the screw distal end and the screw proximal end.

2. The snap-off screw of claim 1 wherein the screw region includes a recessed area and the driver attachment end is positioned within the recessed area.

3. The snap-off screw of claim 2 wherein the screw body includes a breakoff area that is positioned within the recessed area, the breakoff area being the area in which the drive shaft region becomes decoupled from the screw region.

4. The snap-off screw of claim 1 wherein breakoff area is encircled by the head area.

5. The snap-off screw of claim 1 wherein the breakoff area is recessed from the head area.

6. The snap-off screw of claim 1 wherein the breakoff area is at least approximately 0.001 inches from the screw proximal end.

7. The snap-off screw of claim 6 wherein the breakoff area is at least approximately 0.01 inches from the screw proximal end.

8. A snap-off screw for screwing into a bone region, the snap-off screw comprising: a screw body including (i) a screw region having a screw distal end, an opposed screw proximal end, a threaded area positioned near the screw distal end, a head area positioned at the screw proximal end, and a recessed area that is positioned at the screw proximal end, and (ii) a driver region having a driver attachment end and an opposed driver distal end, the driver attachment end being coupled to the screw region within the recessed area.

9. The snap-off screw of claim 8 wherein the screw body includes a breakoff area that is positioned within the recessed area, the breakoff area being the area in which the drive shaft region becomes decoupled from the screw region.

10. The snap-off screw of claim 9 wherein breakoff area is encircled by the head area.

11. The snap-off screw of claim 8 wherein the breakoff area is recessed from the head area.

12. The snap-off screw of claim 8 wherein the breakoff area is at least approximately 0.001 inches from the screw proximal end.

13. The snap-off screw of claim 12 wherein the breakoff area is at least approximately 0.01 inches from the screw proximal end.

14. A method of engaging a bone region, the method comprising the steps of: threading a screw region of a snap-off screw into a bone region, the screw region including a screw distal end, an opposed screw proximal end, a threaded area, and a head area positioned at the screw proximal end, anddecoupling a driver region of the snap-off screw from the screw region so that a screw break surface of the screw region is recessed below at least a portion of the head area.

15. The method of claim 14 wherein the screw region includes a recessed area and wherein the step of decoupling includes the step of the screw break surface being positioned within the recessed area.

16. The method of claim 15 wherein the screw body includes a breakoff area that is positioned within the recessed area, the breakoff area being the area in which the drive shaft region becomes decoupled from the screw region.

17. The method of claim 16 wherein breakoff area is encircled by the head area.

18. The method of claim 16 wherein the breakoff area is recessed from the head area.

19. The method of claim 16 wherein the break-off area is at least approximately 0.001 inches from the screw proximal end.