Patent ID: 8361130

Claim:
A bone fixation device comprising: a u-shaped receiving head having proximal and distal ends, and a recess formed in the proximal end of the receiving head and adapted to seat a spinal rod therein; a threaded shank extending distally from the distal end of the receiving head; an expandable cylindrical body disposed within a lumen extending through the threaded shank and having an anti-rotation mechanism formed on a distal end thereof, the anti-rotation mechanism being located distal of the distal end of the receiving head and around a proximal portion of the threaded shank, such that the anti-rotation mechanism is configured to interact with bone to prevent rotation of at least one of the threaded shank and the receiving head relative to the bone; and a deployment member; wherein advancing the deployment member into an inner lumen of the cylindrical body causes the anti-rotation mechanism to expand radially outward.