Hearing results with a hydroxylapatite/titanium bell partial ossicular replacement prosthesis.

Abstract

To study the preliminary hearing results in patients receiving a hybrid hydroxylapatite/titanium bell partial ossicular replacement prosthesis (PORP) and compare these with a cohort of patients receiving a HAPEX PORP. We hypothesized that the design of the hybrid PORP would enhance its acoustic properties. In particular, the titanium bell, which allows the prosthesis to be freestanding, would obviate the need for Gelfoam, preventing fibrosis. A retrospective study was made of two cohorts of patients. A computerized otologic database was used to identify all patients implanted with either PORP. The four-frequency (500, 1000, 2000, and 3000 Hz) pure-tone average air-bone gap (PTA-ABG) and ABG values for individual frequencies were compared using the Student test. The PTA-ABG for the titanium bell prosthesis was 9.8 +/- 5.7 dB, compared with 13.2 +/- 8.3 dB for the HAPEX PORP, which was statistically significant ( P<.05). The average ABG values at 500 and 1000 Hz were also statistically significantly improved with the titanium bell PORP ( P<.05). The titanium bell PORP showed improved postoperative results for the PTA-ABG and at 500 Hz and 1000 Hz. The prosthesis is freestanding and may provide better coupling with the capitulum, factors which may lead to improved hearing results in the lower frequencies.