Bioglass middle ear prosthesis: long-term results.

The purpose of this study was to review the University of Florida's long-term results with Bioglass middle ear prostheses. Between April 1984 and November 1987, 37 patients were implanted with Bioglass prostheses (25 total and 12 partial ossicular replacements). Twenty-one patients had postoperative data of at least 24 months (range, 24 to 126 months; mean, 86 months; median, 100 months), and five patients had > 10 years' follow-up. In three cases, portions of fractured prostheses extruded, leaving an intact tympanic membrane. One patient with a total ossicular prosthesis was reexplored at 38 months for conductive hearing loss and found to have a prosthesis fracture (n = 1). There were no extrusions of intact prostheses, even in patients in whom the prosthesis was placed directly under the tympanic membrane or graft (n = 12). After 24 months, the mean pure-tone average air-bone gap was 24 dB (24% had ABG < or = 10 dB; 53% had ABG < or = 20 dB). Air-bone gap closures were stable over time. Our results demonstrated that Bioglass middle ear prostheses have excellent long-term tissue compatibility. The four failures are attributed to fractures in early experimental prototypes.