Hydroxylapatite ossicular replacement prostheses: preliminary results.

Hearing results and extrusion rate for 89 consecutive patients receiving hydroxylapatite prostheses for hearing reconstruction were evaluated and compared to a control group of 75 patients who had received homograft bone or Plasti-Pore prostheses. At the 3-month follow-up, there were no cases of extrusion of the hydroxylapatite prostheses. Hearing success was defined as a postoperative air-bone gap of less than or equal to 15 dB for incus prostheses and partial ossicular replacement prostheses or less than or equal to 25 dB for incus-stapes prostheses and total ossicular replacement prostheses. There was a statistically significant difference in the distribution-of-success rate by prosthesis type for the hydroxylapatite. Incus, incus-stapes, and total ossicular replacement prosthesis results were similar, but partial ossicular replacement prosthesis results were poorer. The overall success rate in the hydroxylapatite group was 51.2%; in the control group, it was 60%. Hearing results tended to be better with the hydroxylapatite incus prosthesis than with the homograft bone incus, but poorer with the hydroxylapatite partial ossicular replacement prosthesis than with the Plasti-Pore. Several technical modifications of the prosthesis that may improve results with the hydroxylapatite partial ossicular replacement prosthesis are suggested. Hydroxylapatite middle ear prostheses appear to be a reasonable alternative to other more commonly used prostheses, which carry disadvantages related to the use of human tissue.