Anti-unscrewing and multi-angular fastening apparatuses and methods for surgical bone screw/plate systems

Abstract

A fastening apparatus includes a fastener and a fastener receiving member, the apparatus enabling the fastener to be affixed to the fastener receiving member at a variable insertion angle selected by the user and providing an anti-unscrewing feature. The fastener includes an elongate section and an adjoining head section having a slot therein. The fastener receiving member includes one or more apertures having a contact region through which one or more corresponding fasteners can be inserted. The contact region includes a matrix of protrusions having a density and strength sufficient to render contact region tappable by the thread of the head section of the fastener. The thread on the head section is driven into the contact region at the selected insertion angle. As a result, the protrusions project into the at least one slot preventing the fastener from backing out from fastener receiving member. A fastener driver is also disclosed.

What is claimed is: 
     
         1 . A surgical fastening apparatus adapted to provide anti-unscrewing features, comprising:
 (a) a fastener comprising an elongate section and an adjoining head section disposed along a fastener axis, the head section comprising a thread and an at least one slot defined in an outer periphery of the head section that extends therewithin; and   (b) a fastener receiving member comprising first and second opposing major surfaces, an inside surface extending between the first and second major surfaces and defining an aperture generally coaxially disposed about an aperture axis, and a tappable contact region disposed on the inside surface, wherein the tappable contact region is extendable into the slot of the fastener to prevent backing out of the fastener and the tappable contact region is deflectable from the slot of the fastener to permit removal of the fastener;   (c) wherein the tappable contact region comprises a porous fiber metal matrix.   
     
     
         2 . The apparatus according to  claim 1 , wherein the fiber metal matrix comprises a plurality of titanium-containing fibers. 
     
     
         3 . The apparatus according to  claim 1 , wherein the at least one slot is a plurality of slots. 
     
     
         4 . The apparatus according to  claim 1 , wherein the fastener is a surgical bone screw. 
     
     
         5 . The apparatus according to  claim 1 , wherein the elongate section comprises a thread. 
     
     
         6 . The system according to  claim 5 , wherein the tappable contact region is tappable by the thread of the elongate section of the fastener. 
     
     
         7 . The apparatus according to  claim 5 , wherein the elongate section comprises a first outer surface, and the thread of the elongate section extends along a length of the first outer surface in generally helical relation to the fastener axis. 
     
     
         8 . The apparatus according to  claim 7 , wherein the head section comprises a second outer surface, and the thread of the head section extends along a length of the second outer surface in generally helical relation to the fastener axis. 
     
     
         9 . The apparatus according to  claim 1 , wherein the head section has one of a rounded vertical profile, a substantially hemispherical vertical profile, a frusto-conical vertical profile, and a converging/diverging vertical profile. 
     
     
         10 . The apparatus according to  claim 1 , wherein the first and second major surfaces of the fastener receiving member define a surgical plate. 
     
     
         11 . The apparatus according to  claim 1 , wherein the tappable contact region comprises an insert fitted to the inside surface. 
     
     
         12 . The apparatus according to  claim 1 , wherein the fastener is inserted at an angle that ranges from approximately 0 to approximately 90 degrees. 
     
     
         13 . A surgical angular insertion tool for facilitating rigid angular control of a fastener, comprising:
 (a) an elongate member having first and second ends;   (b) a nipple extending from the first end to be received within a cavity of a head of the fastener; and   (c) at least one engagement portion extending from the elongate member to be received in a slot within the head of the fastener, the engagement portion extendable to an end of the slot to align with an outer surface of the head of the fastener;   (d) wherein the nipple provides rigid control of an angle at which the fastener is inserted.   
     
     
         14 . The angular insertion tool according to  claim 13 , wherein the nipple is threaded. 
     
     
         15 . The angular insertion tool according to  claim 13 , further comprising slot engagement portions at the first end for providing engagement with the fastener such that the fastener can be driven in a rotational manner. 
     
     
         16 . The angular insertion tool according to  claim 13 , wherein the elongate member comprises a sleeve portion. 
     
     
         17 . The angular insertion tool according to  claim 16 , further comprising an elongate cannulated shaft defined by the sleeve portion, wherein the shaft extends the entire length of the device. 
     
     
         18 . The angular insertion tool according to  claim 17 , wherein the elongate cannulated shaft can receive a guide wire to assist in properly aligning the device and the fastener. 
     
     
         19 . The angular insertion tool according to  claim 17 , further comprising a driver rod having proximal and distal ends and being fittingly received within the elongate cannulated shaft, wherein the distal end is threaded and the nipple is fixed to the proximal end, such that the nipple threadingly engages the cavity of the fastener. 
     
     
         20 . The angular insertion tool according to  claim 19 , further comprising a ram threadingly engaging the distal end of the driver rod and the ram being positioned proximate the second end of the angular insertion tool.