Patent ID: 8936624
Filing Date: 2015-01-20
Classification: A61B,Y10T

Abstract:
1. A polyaxial fixation device, comprising: a fastener having a shank and a head formed on a proximal end of the shank, the head extending from a proximal surface to the shank, the head including a spherical surface with a radially extending shoulder extending around a periphery of the head spaced from the proximal surface of the head, wherein the shoulder is disposed closer to the proximal surface of the head than the shank; a receiver member having a passage formed along a longitudinal axis of the receiver member and adapted to polyaxially seat the spherical surface of the head of the fastener; a spacer received in said axial passage of said receiver member and engageable with said head, the spacer having a U-shaped channel in a proximal surface thereof adapted to receive a spinal fixation element; and a ring member disposed within the receiver member, the entire ring member positioned below the bottom-most portion of the U-shaped channel and above the shoulder of the head, the ring member providing a translating force against an inner wall of the receiver member generating a frictional force exerted on the head to enable the shank to be maintained in a desired angular orientation relative to the receiver member in the absence of the spinal fixation element and before locking the head within the receiver member.