Support structure implant for a bone cavity

Abstract

A support structure implant for location within a bone cavity to support the bone which defines the cavity is formed from wires by braiding in a machine direction from a first end of the structure towards an opposite second end. The wires are formed into loops at the first end of the structure so that two lengths of wire extend away from each loop and are formed into the braid. Each of the wires which is formed into the braid is held at the second end of the structure in a clamp. The clamp is provided by a support ring and a clamp ring which is formed from a shape memory alloy which can shrink to clamp the wires against the support ring when heated.

1 . A method of making a stranded support structure implant for location within a bone cavity to support the bone which defines the cavity, comprising the steps of:
 a. forming loops in a plurality of wires so that two lengths of each wire extend from each loop and fastening the loops against a support,   b. braiding the two lengths of each of the wires to form the support structure having a first end provided by the loops in the wires and an opposite second end,   c. clamping each of the wires at the second end of the support structure so as to retain the braided structure.   
     
     
         2 . The method of  claim 1 , further comprising the step of providing a clip that includes a plurality of spaced apart fingers, and inserting the fingers through the loops so as to restrict relative movement between the loops. 
     
     
         3 . The method of  claim 1 , wherein the clamping step comprises clamping the wires between a support ring and a clamp ring. 
     
     
         4 . The method of  claim 1 , further comprising the step of heating the wires to set the shape of the support structure. 
     
     
         5 . The method of  claim 1 , wherein the support comprises a first form that has a start end and a finish end with an axis extending between them, and wherein the braid is formed over the first form from the start end towards the finish end while the form is mounted in a braiding machine with the axis aligned with the braiding axis of the machine. 
     
     
         6 . The method of  claim 5 , wherein the form has a plurality of hooks at or towards the start end and the loops are captured as a result of extending around respective ones of the hooks. 
     
     
         7 . The method of  claim 5 , wherein the transverse dimension of the form is less at the finish end than the transverse dimension of the form at a point between the start end and the finish end. 
     
     
         8 . The method of  claim 7 , wherein the form includes an approximately cylindrical portion at the finish end. 
     
     
         9 . The method of  claim 5 , further comprising the steps of removing the first form from within the braid and placing a second form within the braid. 
     
     
         10 . The method of  claim 9 , wherein the configuration of the second form is different from that of the first form, and wherein the method further comprising the step of heat setting the wires over the second form. 
     
     
         11 . The method of  claim 10 , wherein the transverse dimension of the first form at the start end of the support structure is greater than the transverse dimension of the second form at the start end of the support structure. 
     
     
         12 . The method of  claim 10 , wherein the first form comprises a generally cylindrical portion at the start end contiguous with a hemispherical portion. 
     
     
         13 . The method of  claim 12 , wherein the cylindrical portion tapers inwardly in a direction away from the hemispherical portion towards the start end. 
     
     
         14 . The method of  claim 12 , wherein the second form comprises an approximately spherical portion. 
     
     
         15 . A support structure implant for location within a bone cavity to support the bone that defines the cavity, wherein the structure is formed from wires by braiding in a machine direction from a first end of the structure towards an opposite second end, and wherein each of the wires formed into the braid is held at the second end of the structure in a clamp that comprises a support and a shape memory alloy clamp ring which can clamp the wires between the ring and the support. 
     
     
         16 . A method of making a stranded support structure implant for location within a bone cavity to support the bone which defines the cavity, which comprises:
 a. braiding a plurality wires to form the support structure from a first end to an opposite second end,   b. positioning the wires at the second end of the support structure between a support and a shape memory alloy clamp ring, and   causing the shape memory alloy clamp ring to clamp the wires between the ring and the support so as to retain the braided structure.