Bone Cement With Adapted Mechanical Properties

Abstract

A bone cement is shown that includes a monomer, and a non-reactive substance that is fully miscible with the monomer. A resulting cured bone cement exhibits desirable properties such as modification in a stiffness of the material. Modified properties such a stiffness can be tailored to match bone properties and reduce an occurrence of fractures adjacent to a region repaired with bone cement. One example includes adjacent vertebral body fractures in vertebroplasty procedures.

What is claimed: 
     
         1 . A method of forming bone cement, comprising:
 identifying a mechanical property of bone;   forming a fluid phase, comprising mixing a monomer and a polymerizing agent;   adding a powder phase to the fluid phase; and   adding a miscible substance to the fluid phase in an amount sufficient to substantially match a mechanical property of the bone cement to the identified mechanical property of bone.   
     
     
         2 . The method of  claim 1 , wherein the substance comprises an amount between 20% and 60% of the fluid phase. 
     
     
         3 . The method of  claim 1 , wherein the substance comprises an amount between 30% and 60% of the fluid phase. 
     
     
         4 . The method of  claim 1 , wherein the substance comprises an amount between 30% and 50% of the fluid phase. 
     
     
         5 . The method of  claim 1 , wherein the substance comprises an amount between 20% and 45% of the fluid phase. 
     
     
         6 . The method of  claim 1 , wherein the substance comprises an amount of between 20% and 30% of the fluid phase. 
     
     
         7 . The method of  claim 1 , wherein the substance comprises an amount of about 25% of a total liquid component. 
     
     
         8 . The method of  claim 1 , further including adding a radiopaque agent to the fluid phase. 
     
     
         9 . The method of  claim 1 , wherein the powder phase comprises poly methyl methacrylate (PMMA) powder. 
     
     
         10 . The method of  claim 1 , wherein the powder phase comprises hydroxyapatite powder. 
     
     
         11 . The method of  claim 1 , wherein the miscible substance does not react with the powder phase. 
     
     
         12 . The method of  claim 1 , wherein the substance creates a microporous structure in the bone cement. 
     
     
         13 . The method of  claim 1 , wherein the monomer comprises methyl methacrylate (MMA) monomer, and the miscible substance comprises n-methyl-pyrrolidone (NMP). 
     
     
         14 . The method of  claim 1 , wherein the monomer comprises methyl methacrylate (MMA) monomer, and the miscible substance comprises dimethyl-sulfoxide (DMSO). 
     
     
         15 . The method of  claim 1 , wherein the monomer comprises methyl methacrylate (MMA) monomer, and the miscible substance comprises polyethylene glycol (PEG). 
     
     
         16 . The method of  claim 1 , wherein the monomer comprises methyl methacrylate (MMA) monomer, and the miscible substance comprises cellulose or cellulose derivate. 
     
     
         17 . The method of  claim 1 , wherein the monomer comprises methyl methacrylate (MMA) monomer, and the miscible substance comprises NMP, DMSO, polyethylene glycol (PEG), cellulose, cellulose derivate or any combination thereof. 
     
     
         18 . The method of  claim 1 , wherein the bone is osteoporotic bone. 
     
     
         19 . The bone cement according to  claim 1 , wherein an elastic modulus of the bone cement is between 50 MPa and 2000 MPa. 
     
     
         20 . The bone cement according to  claim 1 , wherein an elastic modulus of the bone cement is between 300 MPa and 1500 MPa. 
     
     
         21 . The bone cement according to  claim 1 , wherein an elastic modulus of the bone cement is between 500 MPa and 1200 MPa. 
     
     
         22 . The bone cement according to  claim 1 , wherein an elastic modulus of the bone cement is between 100 MPa and 1000 MPa. 
     
     
         23 . The bone cement according to  claim 1 , wherein a yield strength of the bone cement is between 30 MPa and 100 MPa. 
     
     
         24 . The bone cement according to  claim 1 , wherein a yield strength of the bone cement is between 40 MPa and 80 MPa. 
     
     
         25 . The bone cement according to  claim 1 , wherein the bone cement has a Young's modulus that matches osteoporotic bone. 
     
     
         26 . The bone cement according to  claim 1 , wherein the miscible substance is added to reduce elastic modulus, yield strength, or both, of the bone cement.