Patent ID: 7166129

Claim:
A method for forming an interbody spinal implant having a plurality of bone engaging structures for insertion between adjacent vertebral bodies of a human spine, the method comprising the steps of: providing the implant comprising a leading end for introduction of the spinal implant into the spine, an opposite trailing end, spaced apart sides therebetween, a mid-longitudinal axis through the leading and trailing ends, and opposite upper and lower surfaces between said leading and trailing ends and said spaced apart sides, said upper surface adapted for placement toward the bone of one of the vertebral bodies and said opposite lower surface adapted for placement toward the bone of the other of the vertebral bodies when said implant is placed between the adjacent vertebral bodies; and forming a plurality of surface projections as part of the upper and lower surfaces of the implant, each of the surface projections having a base with a length and a width, each of the surface projections having a height perpendicular to the length and the width, at least two of the surface projections each having at least one forward facet directed at least in part toward the leading end and at least one rearward facet directed at least in part toward the trailing end, said rearward facet terminating at a first location proximate the base, said rearward facet terminating at a second location proximate said forward facing facet, the first location being closer than the second location to a vertical plane transverse to the mid-longitudinal axis representing the furthest distal extent of the leading end of the implant, each of said at least two surface projections being formed to have opposed side facets extending from the base and being directed generally toward said spaced apart sides of the implant, respectively, said side facets converging toward one another between said forward facet and said rearward facet of each of said at least two surface projections, the width of the base of each of said at least two surface projections being greater than the respective height of each of said at least two surface projections.