OSSICULOPLASTY WITH POLYMALEINATE IONOMERIC PROSTHESIS

With the continued concern over the possible transmission of viral inf ections through homologous middle ear implants, there is increasing pr essure to develop a truly biocompatible alloplastic middle ear prosthe sis, The polymaleinate ionomer, which has been used in dentistry as a filling and luting material for more than 15 years, has recently been used to construct total and partial ossicular replacement prostheses. In an attempt to evaluate these new implants, a multicenter prospectiv e clinical trial was initiated. To date, 92 patients have undergone im plantation. The follow-up interval ranged from 3 months to 22 months. Although it is premature to discuss the long-term results, the prelimi nary surgical experience and audiometric data with these implants are reviewed. From a surgical perspective, the ionomeric prostheses were e asily contoured with a diamond burr and were not prone to shattering. Preliminary follow-up audiometric data were available on 80 patients ( 59 partial ossicular replacement prostheses and 21 total ossicular rep lacement prostheses). Of the 59 partial ossicular replacement prosthes es the air-bone gaps (average of 500 Hz, 1 kHz, 2 kHz and 3 kHz) were as follows: 0 dB to 10 dB, 15 (25%) of 59; 11 dB to 20 dB, 20 (34%) of 59; 21 dB to 30 dB, 11 (19%) of 59; and greater than 30 dB, 13 (22%) of 59. Of the 21 total ossicular replacement prostheses the air-bone g aps were as follows: 0 dB to 10 dB, 6 (29%) of 21; 11 dB to 20 dB, 6 ( 29%) of 21; 21 dB to 30 dB, 5 (24%) of 21; and greater than 30 dB, 4 ( 19%) of 21.