Joint spacer

Abstract

To change a spatial relationship between two or more bones in a patient's body, a wedge member is moved into a joint between the bones. The wedge member may have a cam-shaped configuration and be rotated through less than a revolution to apply force against the bones. The wedge member may have a porous construction which enables bone to grow through the wedge member and immobilize the joint. The wedge member may be coated with and/or contain bone growth promoting material. The wedge member may be connected to only one of the bones or may be connected to two adjacent bones. If the wedge member is connected to only one bone, the joint may be capable of being flexed after the wedge member is inserted into the joint.

I claim: 
     
         1 . An implantable device for maintaining a spatial relationship between a first bone and a second bone of a joint, the implantable device comprising:
 a body formed of a polymeric material having a trailing end, a leading end, an upper surface and a lower surface, the upper and lower surfaces configured such that the body is thicker at the trailing end than at the leading end, a tooling socket extending into the trailing end, an upper mounting tab integrally formed with the body and extending upwardly from the upper surface, a lower mounting tab integrally formed with the body and extending downwardly from the lower surface, an upper fastener hole in the upper mounting tab and a lower fastener hole in the lower mounting tab, the tooling socket positioned between the upper and lower fastener holes;   an upper fastener having a head and a threaded shaft, the upper fastener configured for positioning in the upper fastener hole and for positioning in the first bone in a mounted configuration; and   a lower fastener having a head and a threaded shaft, the lower fastener configured for positioning in the lower fastener hole and for positioning in the second bone in the mounted configuration.   
     
     
         2 . The implantable device of  claim 1 , wherein the heads of the upper and lower fasteners are positionable in engagement with the trailing end in the mounted configuration. 
     
     
         3 . The implantable device of  claim 1 , wherein the upper fastener hole defines an upper longitudinal axis and the lower fastener hole defines a lower longitudinal axis, the upper and lower longitudinal axes oriented generally perpendicular to the trailing end. 
     
     
         4 . The implantable device of  claim 1 , wherein the body further includes a first side portion and a second side portion, the first and second side portions extending between the upper and lower surfaces. 
     
     
         5 . The implantable device of  claim 4 , wherein the first and second side portions taper from the trailing end toward the leading end. 
     
     
         6 . The implantable device of  claim 1 , wherein the tooling socket is comprised of a hexagonal socket, the hexagonal socket generally centered on a longitudinal central axis of the body, the hexagonal socket configured to receive a suitable tool to rotate the body through less than one revolution. 
     
     
         7 . The implantable device of  claim 1 , wherein the upper and lower surfaces are substantially flat. 
     
     
         8 . The implantable device of  claim 7 , wherein the upper and lower surfaces are generally smooth. 
     
     
         9 . The implantable device of  claim 1 , wherein the leading end has a blunt end portion. 
     
     
         10 . The implantable device of  claim 1 , wherein the leading end tapers to a sharp leading edge. 
     
     
         11 . The implantable device of  claim 1 , wherein the body further includes a bone growth passage formed therein, the bone growth passage extending between the upper surface and the lower surface, the bone growth passage configured to facilitate bone growth through the body between the first bone and the second bone in a mounted configuration. 
     
     
         12 . The implantable device of  claim 11 , wherein the bone growth passage is packable with bone growth material. 
     
     
         13 . The implantable device of  claim 11 , wherein the body includes a longitudinal central axis, the bone growth passage is substantially linear and oriented substantially perpendicular to the longitudinal central axis. 
     
     
         14 . The implantable device of  claim 11 , wherein the bone growth passage is comprised of a first passage and a second passage, the first and second passages being substantially linear, the first passage extending between the upper and lower surfaces and the second passage extending between the upper and lower surfaces. 
     
     
         15 . The implantable device of  claim 1 , wherein shapes of the upper and lower surfaces of the body are configured to correspond to the first and second bones, the first and second bones being comprised of a superior vertebra and an inferior vertebra, respectively. 
     
     
         16 . The implantable device of  claim 1 , wherein the body is coated with a material that promotes bone growth. 
     
     
         17 . The implantable device of  claim 1 , wherein the body includes a compartment formed therein, the compartment configured for packing with bone growth inducing material, the compartment defining upper and lower inner side surfaces, the upper and lower inner side surfaces being smaller than the upper and lower surfaces, respectively. 
     
     
         18 . The implantable device of  claim 1 , wherein the body tapers from the trailing end toward the leading end, the taper being configured to facilitate insertion of the body into the joint, the joint being comprised of a vertebral joint between a superior vertebra and an inferior vertebra. 
     
     
         19 . The implantable device of  claim 1 , wherein the body includes a first side surface and a second side surface extending between the trailing end and the leading end, the first and second side surfaces having an irregular configuration such that the first and second side surfaces are configured to be aligned with outer surfaces of the first and second bones, wherein the first bone is a superior vertebra and the second bone is an inferior vertebra. 
     
     
         20 . The implantable device of  claim 1 , wherein the body includes a first side surface and a second side surface extending between the trailing end and the leading end, the first and second side surfaces being nonlinear and shaped to correspond to the configuration of the joint, wherein the joint is between vertebrae.