Bone grafts

Abstract

Spinal spacers 20 are provided for fusion of a motion segment. The spacers include a load bearing member 21 having a wall 22 sized for engagement within a space between adjacent vertebrae to maintain the space and an effective amount of an osteogenic composition to stimulate osteoinduction. The osteogenic composition includes a substantially pure osteogenic factor in a pharmaceutically acceptable carrier. In one embodiment the load bearing member includes a bone graft impregnated in an osteogenic composition. In another embodiment, the osteogenic composition 30 is packed within a chamber 25 defined in the graft. Any suitable configuration of a bone graft is contemplated, including bone dowels, D-shaped spacers and cortical rings.

What is claimed:  
     
         1 . A spinal spacer comprising a load bearing member having a wall sized for engagement within a space between adjacent vertebrae to maintain the space, said load bearing member including a bone graft impregnated with an effective amount of an osteogenic composition to stimulate osteoinduction, said osteogenic composition including a substantially pure osteogenic factor in a pharmaceutically acceptable carrier.  
     
     
         2 . The spacer of  claim 1  wherein said osteogenic factor is a purified bone morphogenic protein isolated from bone.  
     
     
         3 . The spacer of  claim 1  wherein said osteogenic factor protein is a recombinant human protein.  
     
     
         4 . The spacer of  claim 3  wherein said bone morphogenic protein is selected from the group consisting of BMP-1, BMP-2, BMP-3, BMP-4, BMP-5, BMP-6, BMP-7, BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, a mixture thereof and a heterodimer thereof.  
     
     
         5 . The spacer of  claim 4  wherein said bone morphogenic protein is rhBMP-2, rhBMP-7 or a mixture or heterodimer thereof.  
     
     
         6 . The spacer of  claim 1  wherein said carrier is physiological saline.  
     
     
         7 . The spacer of  claim 1  wherein said carrier is buffered sterile water.  
     
     
         8 . The spacer of  claim 1  wherein said member is a cylindrical bone dowel having a diameter larger than the height of the space between the adjacent vertebrae.  
     
     
         9 . The spacer of  claim 8  wherein said bone member defines a chamber and said bone graft is a bone dowel obtained from the diaphysis of a long bone having a medullary canal, said chamber including a portion of said canal.  
     
     
         10 . The spacer of  claim 9  further comprising an effective amount of a second osteogenic composition to stimulate osteoinduction, said second composition packed within said chamber.  
     
     
         11 . The spacer of  claim 10  wherein said second composition has a length which is greater than a length of said chamber and said second composition is disposed within said chamber to contact the endplates of adjacent vertebrae when the graft is implanted between the vertebrae.  
     
     
         12 . The spacer of  claim 11  wherein said second osteogenic composition is selected from the group consisting of autograft, allograft, demineralized bone, calcium phosphate ceramics, and an osteoinductive factor disposed within a pharmaceutically acceptable matrix  
     
     
         13 . The spacer of  claim 1  wherein said member includes an anterior wall and said anterior wall defines a tool engaging hole for receiving an implanting tool.  
     
     
         14 . The spacer of  claim 1  wherein said member includes at least two opposite bone engaging surfaces for contacting a corresponding one of the adjacent vertebrae when the spacer is implanted therebetween, at least one of said engaging surfaces defining surface roughenings.  
     
     
         21 . The spacer of claim  18  wherein said threads define an angle between leading and trailing flanks of adjacent ones of said teeth, said angle between about 50 degrees and 70 degrees.  
     
     
         22 . The spacer of claim  18  wherein each said tooth has a height between about 0.030 inches and about 0.045 inches.  
     
     
         23 . The spacer of claim  18  wherein said dowel includes a tool engaging portion defining a tool engaging hole for receiving an implanting tool.  
     
     
         24 . The spacer of  claim 23  wherein said tool engaging hole is threaded to receive a threaded implanting tool.  
     
     
         25 . A spinal spacer comprising a load bearing member having a wall sized for engagement within a space between adjacent vertebrae to maintain the space, said load bearing member defining a chamber and including a bone graft obtained from the diaphysis of a long bone having a medullary canal said chamber including a portion of the canal, and an effective amount of an osteogenic composition to stimulate osteoinduction, said composition including a substantially pure osteogenic factor in a pharmaceutically acceptable matrix and packed within said chamber.  
     
     
         26 . The spacer of  claim 25  wherein said composition has a length which is greater than a length of said chamber and said composition is disposed within said chamber to contact the endplates of adjacent vertebrae when the spacer is implanted between the vertebrae.  
     
     
         27 . The spacer of  claim 26  wherein said osteogenic factor is a purified bone morphogenic protein isolated from bone.  
     
     
         28 . The spacer of  claim 26  wherein said osteogenic factor is a recombinant human bone morphogenic protein.  
     
     
         29 . The spacer of  claim 28  wherein said osteoinductive factor is a bone morphogenic protein and said protein is selected from the group consisting of BMP-1, BMP-2, BMP-3, BMP-4, BMP-5, BMP-6, BMP-7, BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, a mixture thereof and a heterodimer thereof.  
     
     
         30 . The spacer of  claim 29  wherein said bone morphogenic protein is rhBMP-2, rhBMP-7 or a mixture or heterodimer thereof.  
     
     
         31 . The spacer of  claim 30  wherein said matrix is selected from the group consisting of calcium sulphates, polylactic acids, polyanhydrides, collagen, calcium phosphates and polymeric acrylic esters.  
     
     
         32 . The spacer of  claim 31  wherein said matrix includes a bioceramic.  
     
     
         33 . The spacer of  claim 32  wherein said bioceramic is a calcium phosphate ceramic.  
     
     
         34 . The spacer of  claim 33  wherein said ceramic is a biphasic calcium phosphate ceramic, including hydroxyapatite and tricalcium phosphate.  
     
     
         35 . The spacer of  claim 34  wherein the ratio of hydroxyapatite to tricalcium phosphate is between about 0:100 and about 65:35.  
     
     
         36 . The spacer of  claim 25  wherein said bone dowel includes an outer surface and said outer surface defines a tool engaging hole for receiving an implanting tool.  
     
     
         37 . The spacer of  claim 25  wherein said member is a bone dowel having an outer surface defining threads, said threads being uniformly machined threads, said threads including teeth each having a crest between a leading flank and an opposite trailing flank.  
     
     
         38 . The spacer of  claim 37  wherein said crest of each said tooth is flat, having a width of between about 0.020 inches and about 0.030 inches.  
     
     
         39 . The spacer of  claim 38  wherein said threads define an angle between leading and trailing flanks of adjacent ones of said teeth, said angle between about 50 degrees and 70 degrees.  
     
     
         40 . The spacer of claim 38 wherein each said tooth has a height between about 0.030 inches and about 0.045 inches.  
     
     
         41 . The spacer of claim 37 wherein said dowel includes a tool engaging portion defining a tool engaging hole for receiving an implanting tool.  
     
     
         42 . The spacer of  claim 41  wherein said tool engaging hole is threaded to receive a threaded implanting tool.  
     
     
         43 . The spacer of  claim 25  wherein said graft is a cortical ring obtained by a cross-sectional slice of the diaphysis, said ring including superior and inferior surfaces and said osteogenic factor is a bone morphogenic protein.  
     
     
         44 . The spacer of  claim 43  wherein said protein is selected from the group consisting of BMP-1, BMP-2, BMP-3, BMP-4, BMP-5, BMP-6, BMP-7, BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, a mixture thereof and a heterodimer thereof.  
     
     
         45 . The spacer of  claim 44  wherein said bone morphogenic protein is rhBMP-2, rhBMP-7 or a mixture or heterodimer thereof.  
     
     
         46 . The spacer of  claim 43  wherein said matrix is selected from the group consisting of calcium sulphates, polylactic acids, polyanhydrides, collagen, calcium phosphates and polymeric acrylic esters.  
     
     
         47 . The spacer of  claim 46  wherein said matrix includes a biphasic calcium phosphate ceramic, including hydroxyapatite and tricalciun phosphate.  
     
     
         48 . The spacer of  claim 43  wherein said ring includes an outer surface adjacent and between said superior and inferior surfaces and said outer surface defines a tool engaging hole for receiving an implanting tool.  
     
     
         49 . The spacer of  claim 43  wherein at least one of said superior and inferior surfaces are roughened.  
     
     
         50 . The spacer of  claim 43  wherein at least one of said superior and inferior surfaces includes teeth.  
     
     
         51 . The spacer of  claim 43  wherein at least one of said superior and inferior surfaces defines a waffle pattern.  
     
     
         52 . The spacer of  claim 37  wherein said load bearing member has a compressive strength of at least 10,000 N.  
     
     
         53 . The spacer of  claim 52  wherein said load bearing member has a compressive strength of at least 20,000 N.  
     
     
         54 . The spacer of  claim 37  wherein said load bearing member has a fatigue strength of at least 3200 N at five million cycles.  
     
     
         55 . The spacer of  claim 54  wherein said load bearing member has a fatigue strength of at least 7000 N at five million cycles.  
     
     
         56 . A hollow spinal spacer for engagement between vertebrae, comprising: 
 an anterior wall having a convexly curved anterior surface and opposite ends;    a posterior wall having a flat posterior surface and opposite ends;    two lateral walls, each integrally connected between said opposite ends of said anterior and posterior walls to define a chamber; and    said walls comprised of bone and further defining; 
 a superior face defining a first opening, said opening in communication with said chamber, said superior face having a superior engaging surface; and  
 an opposite inferior face defining a second opening, said second opening in communication with said chamber, said inferior face having an inferior engaging surface.  
   
     
     
         57 . The spacer of  claim 56  wherein said bone is cortical bone obtained from the diaphysis of a long bone having a medullary canal, said chamber including a portion of the medullary canal.  
     
     
         58 . The spacer of  claim 56 , further comprising an effective amount of an osteogenic composition to stimulate osteogenesis, said composition disposed within said chamber.  
     
     
         59 . The spacer of  claim 56  wherein said osteogenic composition includes a material selected from the group consisting of autograft, allograft, a bioceramic and a substantially pure osteogenic factor in a pharmaceutically acceptable matrix.  
     
     
         60 . The spacer of  claim 59  wherein said bioceramic is a biphasic calcium phosphate ceramic.  
     
     
         61 . The spacer of  claim 59  wherein said factor includes a bone morphogenic protein selected from the group consisting of BMP-1, BMP-2, BMP-3, BMP-4, BMP-5, BMP-6, BMP-7, BMP-8, BMP-9, BMP-10, BMP-11, BMP-12 and BMP-13, a mixture thereof and a heterodimer thereof.  
     
     
         62 . The spacer of  claim 61  wherein said matrix is selected from the group consisting of calcium sulphates, polylactic acids, polyanhydrides, collagen, calcium phosphates and polymeric acrylic esters.  
     
     
         63 . The spacer of  claim 56  wherein said anterior wall defines a tool engaging hole for receiving an implanting tool.  
     
     
         64 . The spacer of  claim 63  wherein said tool engaging hole is threaded for receiving a threaded implanting tool.  
     
     
         65 . The spacer of  claim 56  wherein at least one of said engaging surfaces are roughened.  
     
     
         66 . The spacer of  claim 56  wherein at least one of said engaging surfaces includes teeth.  
     
     
         67 . The spacer of  claim 56  wherein at least one of said engaging surfaces defines a waffle pattern.  
     
     
         68 . The spacer of  claim 56  further comprising a blade on at least one of said engaging surfaces.  
     
     
         69 . The spacer of  claim 1  wherein said graft is porous and said composition is contained within said pores.  
     
     
         70 . The spacer of  claim 1  wherein said wall defines a bone growth thru-hole therethrough, said thru-hole sized to receive mesenchymal cells.  
     
     
         71 . The spacer of  claim 25  wherein said wall defines a bone growth thru-hole therethrough, said thru-hole communicating with said chamber and sized to receive mesenchymal cells.  
     
     
         72 . The spacer of  claim 56  wherein said wall defines a bone growth thru-hole therethrough, said thru-hole communicating with said chamber and sized to receive mesenchymal cells.