Intervertebral coupling for two or more vertebrae has intermediate element between fixed and mobile components to allow movement

摘要

The coupling consists of a fixed component (2) such as a pedicular screw for fixing to a vertebra or the sacrum, a mobile component (10), and an intermediate component (22) which allows the mobile component to articulate relative to the fixed one. The intermediate component, made from a metal or plastic, is held in a cavity in the fixed component, and the fixed component is contained at least partly inside a cavity (26) in the intermediate component and has a screw (32) to retain it.