POLYAXIAL SCREW AND ROD SYSTEM

摘要

Screw and rod systems include polyaxial and hinge joints which provide independent first and second ranges of motion. The first and second ranges of motion are additive in a direction along the rod, so that the screw has greater angulation relative to the rod along the rod than transverse to the rod.

主权项

1. A screw and rod system comprising:
a screw with a spherical head, a shaft extending from the spherical head, and a central longitudinal screw axis extending along the shaft; a rod with a central longitudinal rod axis extending along the rod; and a tulip sub-assembly comprising a carrier and a body, wherein the carrier comprises a carrier socket that receives the spherical head of the screw, wherein the body comprises a slot that receives the rod; wherein the carrier forms a hinge joint with the body so that the carrier has a first range of motion relative to the body about a hinge axis, wherein, when the slot of the body receives the rod, the hinge axis is transverse to the rod; wherein the spherical head of the screw forms a ball and socket joint with the carrier socket so that the screw has a second range of motion relative to the carrier about a pivot point centered in the spherical head of the screw, wherein the second range of motion is a cone.