US Patent 7507255 Insertion tool for use with trial intervertebral distraction spacers

A trial spacer kit has a plurality of trial spacers of varying heights. Each spacer includes a disc having a top surface and a bottom surface defining a height of said spacer, an annular groove formed in said disc that defines a central trunk of said spacer, the central trunk extending between the top and bottom surfaces of said spacer, a first radial flange provided at an upper end of the central trunk and a second radial flange provided at a lower end of the central trunk. The annular grooves of the spacers have a common dimension. The radial flanges of a first one of the spacers is thicker than the radial flanges of a second one of the spacers so that the first one of the spacers has a greater height than the second one of the spacers.