Hydroxylapatite ossicular replacement prostheses: a four-year experience.

Between 1987 and 1991, I have used 215 hydroxylapatite middle ear implants, in various styles, for hearing reconstruction. The first such implants were composed entirely of hydroxylapatite. Because of intraoperative difficulties in shaping and trimming these prostheses, hybrid prostheses using Plasti-Pore were developed. For each of four implant designs (incus, incus-stapes, PORP, and TORP), the head is constructed from hydroxylapatite and the shaft from Plasti-Pore. Extrusion rate for the hybrid prostheses is low (4.3%). Hearing results from 47 patients with the hybrid hydroxylapatite prostheses, 140 patients with total hydroxylapatite prostheses, and 75 control group patients with homograft bone or Plasti-Pore prostheses were compared. A "successful" hearing result was achieved in 51.1%, 51.4%, and 60.0% of the three groups, respectively. Surgical technique for use of the new hybrid hydroxylapatite prostheses is described.