Method for 3-D Printing a Custom Bone Graft

Abstract

A method for producing bone grafts using 3-D printing is employed using a 3-D image of a graft location to produce a 3-D model of the graft. This is printed using a 3-D printer and an ink that produces a porous, biocompatible, biodegradable material that is conducive to osteoinduction. This is porous poly methyl methacrylate (PMMA) made osteoinductive by demineralized bone (DMB). The ink is provided as a precursor powder and liquid. The powder contains DMB, sucrose crystals and a polymerization initiator. The liquid contains methyl methacrylate (MMA). Optional compounds include antibiotics, radio-pacifiers, and compounds to increase biodegradability. Once mixed, the MMA polymerizes to PMMA. The ingredients are proportioned so that the ink is delivered through a 10 gauge print nozzle for about 10 minutes per batch. Once the graft is placed, natural bone gradually replaces the graft.

1 . A method for producing a custom bone graft, comprising:
 obtaining a 3-D image of an intended graft location;   creating a 3-D digital model of said custom bone graft using said 3-D image; and   creating, using a 3-D printer said custom bone graft using an ink that dries or reacts to form a porous, biodegradable, biocompatible material that is conducive to osteoinduction and has a load bearing strength comparable to bone.   
     
     
         2 . The method of  claim 1  wherein said porous, biodegradable, biocompatible material comprises collagen and bone morphogenetic proteins (BMP). 
     
     
         3 . The method of  claim 1  wherein said porous, biodegradable, biocompatible material comprises porous Poly Methyl Methacrylate (PMMA) and demineralized allograft bone matrix (DMB). 
     
     
         4 . The method of  claim 3  wherein said ink comprises Methyl Methacrylate (MMA), demineralized allograft bone matrix (DMB), sucrose crystals and a radical polymerization initiator. 
     
     
         5 . The method of  claim 4  wherein said radical polymerization initiator comprises benzoyl peroxide. 
     
     
         6 . The method of  claim 4  wherein said ink further comprises an antibiotic. 
     
     
         7 . The method of  claim 6  wherein said antibiotic consists of one of amoxicillin, doxycycline, gentamicin and clindamycin, or some combination thereof. 
     
     
         8 . The method of  claim 4  wherein said ink further comprises a radio-pacifier. 
     
     
         9 . The method of  claim 8  wherein said radio-pacifier consists of one of zirconium dioxide (ZrO 2 ) and barium sulphate (BaSO 4 ) or some combination thereof. 
     
     
         10 . The method of  claim 4  wherein said ink further comprises a compound to increase the biodegradability of said ink. 
     
     
         11 . The method of  claim 10  wherein said compound to increase the biodegradability of said ink consists of one of cellulose acetate (CA) and cellulose acetate phthalate (CAP) or a combination thereof. 
     
     
         12 . The method of  claim 3  wherein said ink is comprised of a precursor powder and a precursor liquid, and wherein said powder is comprised of demineralized allograft bone matrix (DMB), sucrose crystals and a radical polymerization initiator, and said liquid comprises methyl methacrylate (MMA), and when said precursor powder and said precursor liquid are mixed prior to form said ink in said 3-D printer. 
     
     
         13 . The method of  claim 1  wherein said 3-D image is obtained using one or more X-ray images. 
     
     
         14 . The method of  claim 1  wherein said 3-D digital model further comprises using a standard model of a body part. 
     
     
         15 . The method of  claim 1  further including a semipermeable, resorbable membrane printed on top of said custom bone graft using a second ink. 
     
     
         16 . The method of  claim 15  wherein said second ink comprises poly-vinyl alcohol (PVA) and poly-vinyl pyrrolidone (PVP). 
     
     
         17 . The method of  claim 1  wherein said 3-D image is obtained using a Cone beam imaging device or a cat-scan device. 
     
     
         18 . The method of  claim 1  wherein said porous, biodegradable, biocompatible material comprises a resorbable cement, cellulose, a synthetic bone morphogenetic protein, and one of hydroxyapatite, allograft particulate bone, xenograft particulate bone, or a combination thereof. 
     
     
         19 . The method of  claim 18  wherein said resorbable cement comprises porous Poly Methyl Methacrylate (PMMA), and said synthetic bone morphogenetic protein comprises recombinant human Bone Morphogenetic Protein-2 (rhBMP-2). 
     
     
         20 . A method for producing a custom bone graft, comprising:
 obtaining a 3-D image of an intended graft location;   creating a 3-D digital model of said custom bone graft using said 3-D image;   generating a 3-D digital graft model  310  of a graft negative mold  305  for said custom bone graft using said 3-D digital model; and   creating, using said 3-D digital mold and a porous, biodegradable, biocompatible material that is conducive to osteoinduction and has a load bearing strength comparable to bone, to produce said custom bone graft.   
     
     
         21 . The method of  claim 20  wherein generating a 3-D digital mold of a negative mold for said custom bone graft further comprises using a 3-D printer. 
     
     
         22 . The method of  claim 20  wherein said porous, biodegradable, biocompatible material comprises collagen and bone morphogenetic proteins (BMP). 
     
     
         23 . The method of  claim 20  wherein said porous, biodegradable, biocompatible material comprises porous Poly Methyl Methacrylate (PMMA) and demineralized allograft bone matrix (DMB).