Bone cements as adjuvant techniques for ossicular chain reconstruction.

HYPOTHESIS The osseointegrative capacity of medical-grade bone cement can be used to improve fixation and prevent displacement of an ossicular prosthesis in a guinea pig model. BACKGROUND Successful ossiculoplasty requires a firm connection between the vibrating tympanic membrane and the inner ear. In patients requiring revision ossiculoplasty, half of failures are due to prosthesis displacement. Bone cements have been used as prosthetic material in craniofacial surgery, and their adhesive and osseointegrative properties make them ideal for use in ossicular reconstruction. METHODS Twenty-four adult male guinea pigs underwent a postauricular surgical approach for access to the middle ear. Hydroxyapatite and Dahllite cements were used in an alternating fashion to fix ossicular bone. Four animals were killed immediately to demonstrate mechanical bonding of the ossicles at the time of application. Nineteen animals were killed 8 weeks postoperatively to assess bonding capacity and histologic inflammation. RESULTS Both cements mechanically bonded the ossicles at the time of application, but Dahllite cement set faster in the moist environment of the middle ear space. Histologic examination showed bonding of the ossicles with both cements, with little evidence of inflammation or foreign body reaction. CONCLUSIONS Hydroxyapatite and Dahllite bone cements showed evidence of osseointegration with ossicular bone in the guinea pig model. Further studies are under way to determine the osseointegrative capacity of Dahllite cement between the guinea pig malleus and a partial prosthesis, and any ototoxic effects with use in the middle ear.