Abstract: A known x-stop implantation instrument is modified to provide a slide hammer mechanism to selectively apply an impact force. Both the axial location of the slide hammer and the angle of the slide hammer may be adjusted. A surgeon, when necessary or desirable, may thus apply an impact force to the forward end of the implement having a least a component of force in the direction of insertion of the x-stop device. The invention permits the surgeon to vary both the position along the shaft where the impact is applied as well as the angle at which the impact is applied relative to the direction of insertion.