INTER-VERTEBRAL DISC PROSTHESIS FOR LUMBAR RACHIS THROUGH POSTERIOR SURGERY THEREOF

摘要

A prosthetic inter-vertebral disc for positioning in an inter-somatic space between a pair of adjacent vertebrae (V) and within a natural annulus fibrosus (12) or a remaining portion thereof, comprises a flexible elongated outer annulus member (22) and an expandable inner nucleus member (24). The outer annulus member (22) is adapted to be introduced into the inter-somatic space through a tenotomy opening (16) and to follow an inside wall of the natural annulus fibrosus (12) such as to form a closed loop therewithin with the loop defining a chamber (20). The inner nucleus member (24) is adapted to be introduced in a dehydrated state into the inter-somatic space also through the tenotomy opening (16) and within the outer annulus member (22), and to then be hydrated so as to extend in the chamber (20) peripherally up to the outer annulus member (22). Both the outer annulus member (22) and the inner nucleus member (24) are hydrogels. The outer annulus member (22) is biased outwardly when being introduced in the inter-somatic space such that it follows the inside wall of the natural annulus fibrosus (12). A free end of the outer annulus member (22) extends outwardly of the closed loop and into the tenotomy opening for sealing the same. A method of installing the prosthetic disc is also disclosed.