Vertebral body spacer

Abstract

A vertebral body spacer of the present invention is used by being inserted between a vertebral body and a vertebral body (intervertebral space). The vertebral body spacer has a block body constituted of titanium or a titanium alloy as a main component thereof, and provided with a pair of contact surfaces to be made contact with the vertebral body and the vertebral body. The block body includes a frame-shaped dense part and a porous part provided inside the dense part, and a porosity of at least a surface of the porous part is larger than a porosity of the dense part. According to the present invention, it is possible to maintain an appropriate size between the vertebral bodies (intervertebral space).

What is claimed is: 
     
         1 . A vertebral body spacer to be used by being inserted between vertebral bodies, comprising;
 at least one block body constituted of titanium or a titanium alloy as a main component thereof, and the block body having a pair of contact surfaces to be made contact with the vertebral bodies, and   wherein the block body includes a frame-shaped dense part having a porosity of 10 to 40% and a porous part provided inside the dense part, and a porosity of at least a surface of the porous part is larger than a porosity of the dense part,   wherein the dense part includes a first frame portion configured to contact one of the vertebral bodies and a second frame portion configured to contact the other of the vertebral bodies,   wherein one of surface of the pair of contact surfaces is constituted from the first frame portion of the dense part and the porous part, and the other of surface of the pair of contact surfaces is constituted from the second frame portion of the dense part and the porous part, and   wherein each surface of the pair of contact surfaces constitutes a curved convex surface.   
     
     
         2 . The vertebral body spacer as claimed in  claim 1 , wherein the dense part and the porous part are integrally formed. 
     
     
         3 . The vertebral body spacer as claimed in  claim 1 , wherein the porous part has a plurality of corner portions, and the dense part is provided along the plurality of corner portions of the porous part. 
     
     
         4 . The vertebral body spacer as claimed in  claim 1 , wherein the block body is constituted from a polyhedral body defined by a plurality of surfaces including the pair of contact surfaces, and each of the plurality of surfaces constitutes a flat surface. 
     
     
         5 . The vertebral body spacer as claimed in  claim 1 , wherein at least one block body is constituted from a pair of block bodies. 
     
     
         6 . The vertebral body spacer as claimed in  claim 1 , wherein a whole of the porous part is constituted from a porous body. 
     
     
         7 . The vertebral body spacer as claimed in  claim 1 , wherein an osteoinductive factor is carried on the porous part. 
     
     
         8 . The vertebral body spacer as claimed in  claim 1 , wherein the dense part includes at least one connecting portion connecting the first frame portion and the second frame portion to each other, and wherein the connecting portion serves as a supporting post. 
     
     
         9 . The vertebral body spacer as claimed in  claim 1 , wherein the block body is constituted from a polyhedral body defined by a plurality of surfaces having the pair of contact surfaces, a first surface connecting the pair of contact surfaces at a front end of the block body and a second surface connecting the pair of contact surfaces at a back end of the block body, and
 wherein the pair of contact surfaces are connected to each other at an end portion on the front end of the block body, so that the first surface is omitted.