Patent ID: 7867239

Claim:
A vertebral plating system comprising: a bone screw comprising a screw head and a shaft; and a driver to install said bone screw, said driver comprising an elongated handle, a driver head mounted to said handle, a generally circular mating plate associated with said driver head and formed with at least one elongated slot angularly displaced about said mating plate, said at least one elongated slot having an elongation axis generally along a radius of said mating plate, said at least one elongated slot having a first end arranged toward a center of said generally circular mating plate and a second end arranged radially outward from said first end; and at least three drive pins associated with said driver head, at least one drive pin of said at least three drive pins being movably supported in said at least one elongated slot and having a first range of motion in an axial direction parallel to said handle and a second range of motion in a radial direction along said elongated slot and generally perpendicular to said first range of motion, movement within said first range of motion resulting in movement within said second range of motion, wherein said screw head has a top surface and an outermost edge defining a circumference of the screw head and comprises at least three head segments each of which is flexibly attached to said shaft, each of said at least three head segments defining in the top surface thereof a pin hole sized and configured to receive one of said at least three drive pins, and wherein said segments are movable, in response to movement of said pins along said second range of motion while within said pin holes, between a relaxed position in which the circumference of the screw head is a first circumference and an inner position in which the circumference of the screw head is smaller than the first circumference, whereby, axial pressure on the handle in the direction of the screw, while the pins are within the pin holes, causes said pins to move in said first range of motion and said second range of motion and reduce the circumference of the screw head, and rotation of the handle with the pins in the pin holes transfers a torque from said driver head to said screw head, to install said bone screw.