A lordotic implant has a frusto-conical shape with external threads. Prior to placement of the implant, vertebrae are distracted in a manner to provide a desired lordosis between the vertebrae. The pre-distracted vertebrae are then tapped to provide a tapped bore having a geometry matching the conical...http://www.google.es/patents/US6120506?utm_source=gb-gplus-sharePatente US6120506 - Lordotic spinal implant
