Place holder, in particular for a vertebra body

A prosthesis for insertion in a gap between vertebra wherein a damaged vertebra body has been removed and/or for insertion in a gap between parts of a bone from which a damaged part has been removed, comprising a generally cylindrical jacket disposed in the gap to be secured at its opposite ends to the opposite ends of the vertebra at opposite ends of the gap and/or the opposed ends of the parts of the bone at opposite ends of the gap, said cylindrical jacket comprising a metal tubular structure of a cross section corresponding to substantially the cross section of the opposed ends to be connected, said tubular structure containing a plurality of apertures disposed circumferentially and longitudinally thereof and wherein there are teeth at the opposite ends of the tubular structure, adjacent teeth extending peripherally in opposite directions and wherein the tubular structure is formed of sheet material formed into a cylinder with its ends overlapping and secured to each other by one or more screws engaged within apertures in the overlapping ends and wherein the teeth are bezelled such that the bezelled ends define acute angles forming cutting edges.