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. As the wedge member enters the joint, pivotal movement occurs between the bones to change the orientation of the bones relative to each other. The wedge member may have a circular cross sectional configuration and be moved into the joint by rotating the wedge member about an axis which extends between a thin leading edge portion and a thick trailing edge portion of the wedge member. Alternatively, 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.

1 . A method of changing the spatial relationship between first and second bones, the method comprising: 
 providing a first wedge body;    inserting the first wedge body into a joint located between the first and second bones;    providing a second wedge body; and    inserting the second wedge body into the joint located between the first and second bones, adjacent to the first wedge body;    the first and second wedge bodies cooperating to change the spatial relationship between the first and second bones.    
     
     
         2 . A method as set forth in  claim 1  wherein the second wedge body has a configuration that is different from the configuration of the first wedge body.  
     
     
         3 . A method as set forth in  claim 1  wherein the second wedge body is inserted into the joint at a location alongside the first wedge body between the first and second bones.  
     
     
         4 . An apparatus for use in changing the spatial relationship between first and second bones which are interconnected at a joint in a patient's body, the apparatus comprising: 
 a wedge member which is movable into the joint between the first and second bones, the wedge member having a main body portion and a leading end portion;    the main body portion having a non-tapered configuration including generally parallel first and second major side surfaces;    the leading end portion having a tapered configuration with an edge for facilitating insertion of the wedge member into the joint between the first and second bones.    
     
     
         5 . A method of changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, said method comprising the steps of: 
 forming an opening in a portion of the patient's body to expose the joint interconnecting the first and second bones; and    moving the second bone relative to the first bone;    said step of moving the second bone relative to the first bone including expanding at least a portion of the joint interconnecting the first and second bones by applying force against the first and second bones with a wedge member, closing the opening in the patient's body with at least a portion of the wedge member disposed between the first and second bones at the joint interconnecting the first and second bones, and, thereafter, transmitting force between the first and second bones through the wedge member to maintain the joint in the expanded condition;    the wedge member having a main body portion and a leading end portion, the main body portion having a non-tapered configuration including generally parallel first and second major side surfaces, the leading end portion having a tapered configuration with an edge for facilitating insertion of the wedge member into the joint between the first and second bones.    
     
     
         6 . A method as set forth in  claim 5  wherein the expanding step comprises expanding at least a portion of the joint without substantially pivoting the first and second bones relative to each other.  
     
     
         7 . An implantable device for changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, the device comprising: 
 a wedge body configured and dimensioned for insertion into the joint between the first and second bones;    the wedge body having a thin end portion, a thick end portion, a first major side surface which extends from the thin end portion to the thick end portion, a second major side surface which intersects the first major side surface to form an edge at the thin end portion and extends from the thin end portion to the thick end portion, and a minor side surface which extends between the first and second major side surfaces and tapers from the thick end portion to the thin end portion; and    the wedge body having a disc-shaped configuration.    
     
     
         8 . An implantable device for changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, the device comprising: 
 a wedge body configured and dimensioned for insertion into the joint between the first and second bones;    the wedge body having a thin end portion, a thick end portion, first and second major side surfaces which extend from the thin end portion to the thick end portion, and a minor side surface which extends between the first and second major side surfaces and tapers from the thick end portion to the thin end portion;    the wedge body having a U-shaped configuration    
     
     
         9 . An implantable device as sets forth in  claim 8  wherein the extent of the thin end portion of the wedge member is significantly less than the width of the joint.  
     
     
         10 . An implantable device as sets forth in  claim 8  wherein the wedge body is selected from a group of wedge bodies having differing widths.  
     
     
         11 . An implantable device for changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, the device comprising: 
 a wedge body configured and dimensioned for insertion into the joint between the first and second bones;    the wedge body having a thin end portion, a thick end portion, first and second major side surfaces which extend from the thin end portion to the thick end portion, and a minor side surface which extends between the first and second major side surfaces and tapers from the thick end portion to the thin end portion;    the first major side surface having a non-planar configuration that is contoured to conform to the first bone when the wedge body is in the joint.    
     
     
         12 . An implantable device as set forth in  claim 11  wherein the second major side surface has a non-planar configuration that is contoured to conform to the second bone when the wedge body is in the joint.  
     
     
         13 . An implantable device as set forth in  claim 11  wherein the first major side surface has a curved configuration that is curved about an axis that extends parallel to the direction of insertion of the wedge body into the joint.  
     
     
         14 . An implantable device as set forth in  claim 11  wherein the first major side surface has a convex configuration.  
     
     
         15 . An implantable device as set forth in  claim 11  wherein the first major side surface has a concave configuration.  
     
     
         16 . A method of changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, said method comprising the steps of: 
 forming an opening in a portion of the patient's body to expose the joint interconnecting the first and second bones; and    moving the second bone relative to the first bone;    said step of moving the second bone relative to the first bone including expanding at least a portion of the joint interconnecting the first and second bones by applying force against the first and second bones with a wedge member, closing the opening in the patient's body with at least a portion of the wedge member disposed between the first and second bones at the joint interconnecting the first and second bones, and, thereafter, transmitting force between the first and second bones through the wedge member to maintain the joint in the expanded condition;    the wedge body having a thin end portion, a thick end portion, first and second major side surfaces which extend from the thin end portion to the thick end portion, and a minor side surface which extends between the first and second major side surfaces and tapers from the thick end portion to the thin end portion, and the first major side surface having a non-planar configuration that is contoured to conform to the first bone when the wedge body is in the joint.    
     
     
         17 . A method as set forth in  claim 16  including the step of fixing the wedge body to at least one of the first and second bones.  
     
     
         18 . A method as set forth in  claim 17  wherein the step of fixing the wedge body to at least one of the first and second bones includes fixing the wedge body to both of the first and second bones.  
     
     
         19 . A method as set forth in  claim 17  wherein the step of fixing the wedge body to at least one of the first and second bones includes fixing the wedge body to both of the first and second bones.  
     
     
         20 . A method as set forth in  claim 16  wherein the second major side surface has a non-planar configuration that is contoured to conform to the second bone.  
     
     
         21 . A method as set forth in  claim 20  wherein the wedge member is fixed to the first bone and is not fixed to the second bone.  
     
     
         22 . An implantable device for changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, the device comprising: 
 a wedge body configured and dimensioned for insertion into the joint between the first and second bones;    the wedge body having a thin end portion, a thick end portion, first and second opposite major side surfaces, and a minor side surface which extends between the first and second major side surfaces and tapers from the thick end portion to the thin end portion; and    at least one fastener extensible through the minor side surface into bone to fix the wedge body to bone;    the wedge body having a recess in the minor side surface for receiving the fastener below the minor side surface.    
     
     
         23 . An implantable device as set forth in  claim 22  wherein the fastener is a screw with a head, and the wedge body has a recess in the minor side surface for receiving the fastener head below the minor side surface.  
     
     
         24 . An implantable device as set forth in  claim 22  wherein the fastener recess includes a seat surface extending at an acute angle to the outer side surface thereby to allow the fastener when seated to extend at an acute angle to the length of the wedge body.  
     
     
         25 . A method of changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, said method comprising the steps of forming an opening in a portion of the patient's body to expose the joint interconnecting the first and second bones, and moving the second bone relative to the first bone; 
 said step of moving the second bone relative to the first bone includes applying force against the first and second bones by rotating a wedge member disposed between the first and second bones.    
     
     
         26 . A method as set forth in  claim 25  wherein said step of moving the second bone relative to the first bone by rotating a wedge member comprises: 
 expanding at least a portion of the joint interconnecting the first and second bones by applying force against the first and second bones with the wedge member and pivoting the first bone about an axis which extends through the joint interconnecting the first and second bones; and    wherein the wedge member has first and second arcuate surface areas, said step of applying force against the first and second bones with the wedge member includes rotating the wedge member about an axis which is disposed between the first and second arcuate surface areas and transmitting force to the first and second bones from the first and second arcuate surface areas during rotation of the wedge member about the axis disposed between the first and second arcuate surface areas.    
     
     
         27 . A spinal implant positionable in a joint located between first and second vertebrae, the implant comprising: 
 a unitary body configured and dimensioned for insertion between the first and second vertebrae;    the body having a tapered configuration in the direction of insertion with a flat leading end portion for insertion of the body into the joint between the first and second vertebrae.    
     
     
         28 . A spinal implant positionable in a joint located between first and second vertebrae, the implant comprising: 
 a unitary body configured and dimensioned for insertion in a first direction between the first and second vertebrae;    the body having a tapered configuration in the direction of insertion;    the body having a non-symmetrical configuration about an axis that extends in the direction of insertion.    
     
     
         29 . A spinal implant as set forth in  claim 28  wherein the body has an oval configuration about an axis that extends in the direction of insertion.  
     
     
         30 . An implantable device for changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, the device comprising: 
 a wedge body configured and dimensioned for insertion into the joint between the first and second bones;    the wedge body having a thin end portion, a thick end portion, first and second major side surfaces for engagement with the first and second bones when the wedge body is inserted in the joint, the wedge body being rotatable in the joint to change the spatial relationship between the first and second bones by moving the first major side surface against the first bone and the second major side surface against the second bone; and    the first major side surface being arcuate and the second major side surface being at least partially non-arcuate.    
     
     
         31 . An implantable device as set forth in  claim 30  wherein the second major side surface is flat and the wedge body has a sharp edge between the first and second major side surfaces.  
     
     
         32 . A method of changing a spatial relationship between first and second bones which are interconnected at a joint in a patient's body, said method comprising the steps of: 
 forming an opening in a portion of the patient's body to expose the joint interconnecting the first and second bones;    expanding at least a portion of the joint interconnecting the first and second bones by applying force against the first and second bones with a wedge member;    closing the opening in the patient's body with at least a portion of the wedge member disposed between the first and second bones at the joint interconnecting the first and second bones; and    moving the first bone relative to the second bone.    
     
     
         33 . A method as set forth in  claim 32  further comprising the step of fixing the wedge member to the first bone prior to closing the opening in the patient's body; 
 the wedge member moving with the first bone relative to the second bone.    
     
     
         34 . A method as set forth in  claim 32  wherein the wedge member has a non-planar outer side surface that is contoured to conform to the second bone when the wedge body is in the joint to facilitate movement of the wedge member relative to the second bone.