Friction device for connecting poly-axial screw to connector of spinal fixation device, has ring and bushing positioned against spherical head of screw, to axially pre-position connector relative to axial anchoring position of screw

摘要

The friction device has a ring (8) and a bushing (12) intended to be positioned against a spherical head (9) of a poly-axial screw (4), so as to axially pre-position, before immobilizing, a connector (3) relative to an axial anchoring position of the poly-axial screw. The ring is arranged in a groove (10) arranged in a bore of the connector. The ring includes an opening for allowing axial deformation of the ring at the time of the installation of the spherical head of the poly-axial screw.