Process of making implantable prosthesis material of modified polymeric acrylic (PMMA) beads coated with PHEMA and barium sulfate

Claim 1

A process for producing implantable prosthesis material comprising loose, individual, modified polymethylmethacrylate beads of a particle size which when implanted develop pore sizes that promote bone growth including the steps of: (a) mixing polymethylmethacrylate beads with between about 10 and 20% by volume or between about 21.5 and 43% by weight of barium sulfate of particle size less than one micron; (b) adding between about 4 and 7% by weight (of the polymethylmethacrylate beads) of monomeric hydroxyethyl methacrylate to the polymethylmethacrylatebarium sulfate mixture, and mixing said mixture to effect uniform coating of the PMMA beads; (c) heating the mixture produced in step (b) with a dielectric heater while in a thin layer of about 1/16" to 1/8" thickness until most of the hydroxyethyl methacrylate is polymerized; (d) cooling the mixture to an ambient temperature between about 70 and about 80° F.; (e) breaking up any clumps in the mixture; (f) boiling the mixture in water for about 2 to 3 minutes to extract any remaining monomer; and (g) spreading out the obtained modified polymethylmethacrylate beads for air-drying or force drying.