Vertebroplasty bone cement

Abstract

This invention relates to preferred bone cement formulations.

We claim:  
     
         1 . A process comprising the steps of: 
 a) providing a powder mixture suitable for producing a bone cement, the powder mixture comprising between 20 wt % and about 40 wt % contrast agent,    b) mixing the powder mixture with a liquid component to form a viscous bone cement, and    c) injecting the viscous bone cement into a vertebral body.    
     
     
         2 . The process of  claim 1  wherein the contrast agent comprises barium sulfate.  
     
     
         3 . A powder mixture for producing a bone cement comprising contrast agent grains having a D 50  grain size of at least 3 um.  
     
     
         4 . The powder mixture of  claim 3  wherein the contrast agent grains are BaSO 4 .  
     
     
         5 . A powder mixture suitable for producing bone cement, the powder mixture comprising between 20 wt % and 40 wt % contrast agent and free initiator powder.  
     
     
         6 . A powder mixture suitable for producing a bone cement, the powder mixture comprising between 16 wt % and 40 wt % free zirconia powder, and at least 40 wt % PMMA powder.  
     
     
         7 . A powder mixture suitable for producing bone cement, the powder mixture comprising between 20 wt % and 40 wt % barium sulfate powder, wherein the barium sulfate powder grains are unagglomerated.  
     
     
         8 . A formulation suitable for producing bone cement, comprising a powder component having: 
 a) between 20 and 40 wt % contrast agent and    b) no more than 1.1 wt % initiator powder.    
     
     
         9 . A formulation suitable for producing bone cement comprising: 
 a) a liquid component comprising no more than 2.4 vol % accelerator, and    b) a powder component comprising between 20 wt % and 40 wt % contrast agent.    
     
     
         10 . A powder mixture suitable for use as a bone cement, the powder mixture comprising: 
 a) between 20 wt % and 40 wt % contrast agent (preferably, barium sulfate),    b) no more than 50 wt % co-polymer.    
     
     
         11 . A bone cement formulation comprising: 
 a) a powder component comprising between 20 wt % and 40 wt % contrast agent and an initiator present in an amount defining a powder initiator fraction, and    b) a liquid component comprising an accelerator present in an amount defining a liquid accelerator fraction,    wherein the ratio of the liquid accelerator fraction to the powder initiator fraction is less than 1.75.    
     
     
         12 . A bone cement formulation comprising: 
 a) a powder component comprising between 20 wt % and 40 wt % contrast agent and an initiator present in an amount defining a powder initiator fraction, and    b) a liquid component comprising an accelerator present in an amount defining a liquid accelerator fraction,    wherein the ratio of the liquid accelerator fraction to the powder initiator fraction is between 1.3 and 1.9, and wherein the powder initiator fraction is less than 1.3%.    
     
     
         13 . A bone cement formulation comprising: 
 a) a powder component comprising between 20 wt % and 40 wt % contrast agent and an initiator present in an amount defining a powder initiator fraction, and    b) a liquid component comprising an accelerator present in an amount defining a liquid accelerator fraction,    wherein the ratio of the liquid accelerator fraction to the powder initiator fraction is between 1.67 and 1.99, and wherein the liquid accelerator fraction is less than 2.6 vol %.    
     
     
         14 . A bone cement formulation comprising: 
 a) a powder component comprising between 20 wt % and 40 wt % contrast agent and an initiator present in an amount defining a powder initiator fraction, and    b) a liquid component comprising an accelerator present in an amount defining a liquid accelerator fraction,    wherein the ratio of the liquid accelerator fraction to the powder initiator fraction is between 1 and 2, and wherein the liquid accelerator fraction is less than 1.9 vol %.    
     
     
         15 . A process comprising the steps of: 
 a) providing a powder mixture suitable for producing a bone cement,    b) mixing the powder mixture with a liquid component to form a viscous bone cement, and    c) injecting the viscous bone cement into a vertebral body,    wherein at least a portion of the injection step occurs at least 10 minutes after the mixing step.