Bone fastener and instrument for insertion thereof

Abstract

A bone member fastener for closing a craniotomy includes a cap and a base interconnected by a narrow cylindrical collar. The cap has an externally threaded stud that screws into an internally threaded bore of the collar, thereby allowing the cap and base to be brought into clamping engagement against the internal and external faces of a bone plate and surrounding bone. In a particularly disclosed embodiment, the base of the fastener is placed below a craniotomy hole with the collar projecting into the hole, and the stud of the cap is screwed into the bore of the base from above the hole to clamp a bone flap against the surrounding cranium. This device provides a method of quickly and securely replacing a bone cover into a craniotomy. The distance between the cap and base can be selected by how far the threaded stud of the cap is advanced into the internally threaded collar. The fastener is therefore adaptable for use in several regions of the skull having various thicknesses. An insertion tool with a long handle permits safe and convenient placement of the base between the brain and the internal face of the bone plate. Some disclosed embodiments of the fastener have a cap and base that conform to the curved surface of the skull, for example by having an arcuate shape or flexible members that conform to the curvature of the bone plate and surrounding cranial bone as the fastener is tightened.

What is claimed is:  
     
         1 . A fastener for holding adjacent members together, the fastener comprising: 
 first and second fastening members, wherein at least one of the fastening members has a conforming surface that conforms to a curved member;    a first connector on the first fastening member; and    a second connector on the second fastening member for connecting with the first connector, and holding the first and second fastening members in a fixed relationship that holds the adjacent members together;    wherein the adjacent members are bone plates.