Patent ID: 10321936

Abstract:
Polyaxial pedicle screw with a head in the shape of a ball segment and with a threaded screw shank, wherein a hollow ball segment with a recess for receiving a rod-shaped connector is mounted in the head, in order to permit pivoting movements and rotation movements of the connector, wherein moreover, in the direction of the longitudinal axis of the threaded screw shank, the head in the shape of a ball segment has a cutout with an inner thread in which the rod-shaped connector can be moved in and out and, by means of the inner thread in the cutout, a grub screw can be introduced for blocking the hollow ball segment. According to the invention, a plastic buffer body is fitted in the hollow ball segment and is connected to a ram, wherein the ram has a head which engages in an associated annular groove in the plastic buffer body. Moreover, the plastic buffer body has a circumferential guide ring and a spherical guide stop at one end, wherein an opening for the ram is formed lying opposite the guide stop, and the edge of the opening bears on a shell, which in turn bears on the inner side of the hollow ball segment, in such a way that the plastic buffer body with its guide stop is fixed with pretensioning in the head shaped as a ball segment.