SCREW DRIVER FOR A MULTIAXIAL BONE SCREW

• US 20110313471A1
• Filed: 05/31/2011
• Published: 12/22/2011
• Est. Priority Date: 06/18/2010
• Status: Active Grant

• Current Assignee: Spine Wave Incorporated
• Original Assignee: Spine Wave Incorporated
• Inventors: McLean, Scott, Seyer, Steven
• Granted Patent: US 8,394,108 B2
• Time in Patent Office: Days
• US Class Current: 606/305
• CPC Class Codes: A61B 17/7035 Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
• CPC Class Codes: A61B 17/7082 for driving, i.e. rotating, screws or screw parts specially adapted for spinal fixation, e.g. for driving polyaxial or tulip-headed screws driving other bone screws A61B17/8875

Abstract

A screwdriver for driving a multi-axial bone screw into a vertebra of the spine in one configuration includes an elongate shaft defining a driving tip at its distal end for engaging the head of the bone screw for joint rotational movement. The screw driver also includes an outer sleeve within which the inner shaft rotates freely. The outer retention sleeve releasably attaches to the yoke of the bone screw. Rotation of the inner shaft enables rotation of the bone screw threaded shank while the outer sleeve and yoke remain fixed. In another configuration, instead of the outer retention sleeve the screwdriver comprises a screw engagement member affixed to the shaft for joint rotational movement therewith, the screw engagement member comprising a stop sized to seat within a slot of the bone screw yoke, the stop being configured to rotate the yoke upon rotation shaft. A releasable retention member is provided on the screw engagement member for releasably attaching the screwdriver to the bone screw. Rotation of the shaft with the affixed screw engagement member causes common rotation of the entire bone screw including the threaded shank and the yoke.

Claims

1. A screw driver for driving a multi-axial bone screw into a vertebra of a spine, the bone screw including an elongate shaft having a threaded screw portion at the distal end and a screw head at the proximal end, and a yoke articulatingly attached to the screw head, the yoke having a slot therethrough for receiving a connecting rod and including a lower surface, the yoke having an opening communicating with the screw head, said screw driver comprising:

an elongate inner shaft having a distal end and a proximal end, said inner shaft defining a driving tip at said distal end configured to engage the screw head for rotation thereof; and

an outer retention sleeve disposed about said inner shaft and having a distal end and a proximal end, the inner shaft being freely rotatable within said outer retention sleeve and including said tip at the distal end thereof, the distal end of said outer retention sleeve configured to releasably engage the yoke for joint rotational movement therewith.

2. The screw driver of claim 1, in which the slot of said yoke is defined by a pair of upstanding opposed arms having interior threaded surfaces, wherein said distal end of said outer retention sleeve is threaded exteriorly to engage the interior threaded surfaces of the yoke when said screw driver tip is engaged to the head of said bone screw.

3. A screw driver for driving a multi-axial bone screw into a vertebra of a spine, the bone screw including an elongate shaft having a threaded screw portion at the distal end and a screw head at the proximal end, and a yoke articulatingly attached to the screw head, the yoke having a slot therethrough for receiving a connecting rod and including a lower surface, the yoke having an opening communicating with the screw head, said screw driver comprising:

an elongate shaft having a distal end and a proximal end, said shaft defining a driving tip at said distal end configured to engage the screw head for rotation thereof; and

a screw engagement member affixed to said shaft for joint rotational movement therewith, said screw engagement member comprising a stop sized to seat within the slot of said yoke and configured to rotate said yoke upon rotation of said shaft, and a releasable retention member for releasable attachment to said yoke.

4. The screwdriver of claim 3, in which the slot of said yoke is defined by a pair of upstanding opposed arms having interior surfaces and exterior surfaces respectively and wherein said releasable retention member comprises a pair of flexible elements releasably attachable to said respective pair of arms.

5. The screwdriver of claim 4, wherein each of said opposed arms of said yoke comprises an undercut extending respectively into an interior surface thereof and wherein each of said flexible elements is configured to provide an outward bias and having a projection for releasably extending into said respective interior undercuts in said arms.

6. The screwdriver of claim 4, wherein each of said opposed arms of send yoke comprises a slot extending respectively into an exterior surface thereof and wherein each of said flexible elements is configured to provide an inward bias and having a projection for releasably extending into said respective exterior slots in said arms.

7. The screwdriver of claim 3, further including a handle fixed to said shaft at said distal end thereof, said shaft being of length such that said distal end with said handle extends outside a patient as said bone screw is driven into a vertebra of the spine.

8. The screwdriver of claim 3, further comprising a guide wire lumen extending through said shaft to allow introduction of the shaft over a previously positioned guide wire.