Method and apparatus for providing proper vertebral spacing

Abstract

An expandable osteosynthesis implant has branches ( 5 ) each connected at one end to a seat ( 7 ) which is pierced by an orifice ( 8 ), suitable for being slid from a posterior direction between the facing faces of two consecutive vertebrae in order to hold them a given distance apart and restore stability of the spinal column. According to the invention, said branches ( 5 ) and said seat ( 7 ) define a hollow cage ( 1 ) which, in a “rest” position, has an outside general shape that is a cylinder of circular section, and a portion at least of the inside volume ( 9 ) of the cage ( 1 ) towards the distal ends of said branches ( 5 ) is in the form of a circular truncated cone whose large base is towards said seat ( 7 ), which implant has at least three branches ( 5 ) and, inside said inside volume ( 9 ) at least one spacer ( 2 ) suitable for passing through said orifice ( 8 ) and the large base of the truncated cone.

1 . An expandable osteosynthesis implant comprising branches ( 5 ) each connected at one end to a seat ( 7 ) pierced by an orifice ( 8 ), the implant being characterized in that said branches ( 5 ) and the seat ( 7 ) constitute a hollow cage ( 1 ) which, in a “rest” position, has an outside general shape which is quasi-cylindrical of quasi-circular section, and a portion at least of the inside volume ( 9 ) of the cage ( 1 ) towards the distal ends of said branches ( 5 ) is in the form of a quasi-circular truncated cone whose large base is towards said seat ( 7 ), which implant has at least three branches ( 5 ) and, inside said inside volume ( 9 ) at least one spacer ( 2 ) compatible with the dimensions of the large base of the truncated cone, and such that once the spacer ( 2 ) has been placed in the desired position, no internal part remains in the space defined by said branches ( 5 ), the spacer ( 2 ), and the orifice ( 8 ).