Snap-off surgical screw

• US 8,221,478 B2
• Filed: 02/18/2005
• Issued: 07/17/2012
• Est. Priority Date: 09/14/2004
• Status: Active Grant

• Current Assignee: Wright Medical Technology Incorporated (Stryker Corporation)
• Original Assignee: Wright Medical Technology Incorporated (Stryker Corporation)
• Inventors: Patterson, Chad J., Roberts, Jeffrey G., Fenci, Robert M.
• Primary Examiner(s): Robert, Eduardo C
• Assistant Examiner(s): CARTER, TARA ROSE E
• Application Number:
  US11/060,965
• Publication Number:
  US 20060081553A1
• Time in Patent Office: 2,706 Days
• Field of Search: 606300-320, 411/2, 411 39- 42, 411/476
• US Class Current: 606/305
• CPC Class Codes: A61B 17/1728 for holes for bone plates or plate screws
• CPC Class Codes: A61B 17/1775 for the foot or ankle
• CPC Class Codes: A61B 17/1782 for the hand or wrist
• CPC Class Codes: A61B 17/66 Alignment, compression or distraction mechanisms
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/8014 the extension or compression force being caused by interaction of the plate hole and the screws
• CPC Class Codes: A61B 17/8085 with pliable or malleable elements or having a mesh-like structure, e.g. small strips A61B17/8071, A61B17/8076 take precedence
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 17/8605 Heads, i.e. proximal ends projecting from bone
• CPC Class Codes: A61B 17/8872 Instruments for putting said fixation devices against or away from the bone A61B17/7074, A61B17/808 take precedence
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 2017/681 Alignment, compression, or distraction mechanisms
• CPC Class Codes: A61B 2090/037 with a frangible part, e.g. by reduced diameter

Abstract

A snap-off surgical screw configured for threading into a bone of a patient using a driver member, comprising a shaft extension joined to a screw portion via a frangible connection. The frangible connection comprises at least one defect formed through an outer surface of the frangible connection. The defect is configured to promote selective separation of the shaft extension from the screw portion at the defect. A proximal end of the screw portion is preferably provided with a recess, and the frangible connection is preferably positioned in the recess to thereby configure the shaft extension to snap-off from the screw portion below the proximal end of the screw portion.

Claims

1. A snap-off surgical screw configured for threading into a bone of a patient using a driver member, comprising:

a shaft extension joined to a screw portion via a frangible connection, said frangible connection comprising at least one defect formed through an outer surface of said frangible connection, and said defect configured to promote selective separation of said shaft extension from said screw portion at said defect,

a proximal end of said screw portion having a recess formed in said proximal end thereof, said recess being in the form of a distally recessed well having a sidewall spaced from said frangible connection, said frangible connection positioned in said recess to thereby configure said shaft extension to snap-off from said screw portion below said proximal end of said screw portion,

said shaft extension including a driver engaging portion, said driver engaging portion comprising an enlarged portion adjacent and proximal to said proximal end of said screw portion, said enlarged portion including a plurality of slots therein, each of said slots extending from a proximal end to a distal end of said enlarged portion to thereby form a through slot, and said slots configured for engagement by a driver member.

2. The snap-off surgical screw of claim 1, wherein said enlarged portion has three of said slots.

3. The snap-off surgical screw of claim 1, wherein each of said slots include a tapered wall on an inner center wall thereof.

4. The snap-off surgical screw of claim 1, wherein said driver engaging portion includes a quick connect means for quickly connecting the screw to a quick connect coupling member.

5. The snap-off surgical screw of claim 4, wherein said driver engaging portion includes a non-circumferential portion configured to engage the driver member in a non-rotational relationship.

6. The snap-off surgical screw of claim 1, wherein said defect comprises a substantially circumferential groove.

7. The snap-off surgical screw of claim 1, wherein said defect comprises at least one substantially wedge shaped opening.

8. The snap-off surgical screw of claim 1, wherein said sidewall of said recess is a continuous sidewall axially spaced from said frangible connection.

9. The snap-off surgical screw of claim 8, wherein said shaft extension includes a straight, untapered length-wise rod portion extending proximally from said driver engaging portion, said rod portion axially aligned with said screw portion, and said rod portion having a substantially narrower width than said driver engaging portion.

10. A snap-off surgical screw configured for threading into a bone of a patient using a driver member, comprising:

a shaft extension joined to a screw portion via a frangible connection, said screw portion having a head on a proximal end thereof, said shaft extension having a driver engaging portion, the frangible connection formed in a recess in a proximal end of said head, said recess being in the form of a distally recessed well having a sidewall spaced from said frangible connection, said frangible connection comprising at least one defect, and said defect configured to promote selective separation of said driver shaft extension from said screw portion below said proximal end of said head of said screw portion,

said driver engaging portion comprising an enlarged portion of said shaft extension, said enlarged portion adjacent and proximal to a proximal end of said screw portion, said enlarged portion including a plurality of slots therein, said slots formed along an outer surface of said enlarged portion of said shaft extension, each of said slots having an open outer side, each of said slots extending from a proximal end to a distal end of said enlarged portion to thereby form a through slot, said slots configured for engagement by a driver member, and

said head of said screw comprising an enlarged driver head having slots, said slots comprising open slots formed along an outer surface of said enlarged driver head.

11. The snap-off surgical screw of claim 10, wherein each of said slots includes a tapered wall on an inner center wall thereof.

12. The snap-off surgical screw of claim 11, wherein said defect comprises a substantially circumferential groove.

13. The snap-off surgical screw of claim 11, wherein said defect comprises at least one substantially wedge shaped opening.

14. The snap-off surgical screw of claim 10, wherein said driver engaging portion includes a quick connect means for quickly connecting the screw to a quick connect coupling member.

15. The snap-off surgical screw of claim 14, wherein said driver engaging portion includes a non-circumferential portion configured to engage the driver member in a non-rotational relationship.

16. The snap-off surgical screw of claim 10, wherein said defect comprises a substantially circumferential groove.

17. The snap-off surgical screw of claim 10, wherein said defect comprises at least one substantially wedge shaped opening.

18. The snap-off surgical screw of claim 10, wherein said enlarged portion has three of said slots.

19. The snap-off surgical screw of claim 10, wherein each of said slots extends from a proximal end to a distal end of said enlarged portion to thereby form a through slot.

20. The snap-off surgical screw of claim 10, wherein said sidewall of said recess is a continuous sidewall axially spaced from said frangible connection.

21. The snap-off surgical screw of claim 20, wherein said shaft extension includes a straight, untapered length-wise rod portion extending proximally from said driver engaging portion, said rod portion axially aligned with said screw portion, and said rod portion having a substantially narrower width than said driver engaging portion.