TORPs and PORPs: causes of failure--a report on 446 operations.

This is a review of the causes of failure in 5 1/2 years of personal experience with TORPs and PORPs. Prosthesis extrusion, the cause of failure in less than 5% of 446 TORP and PORP operations, usually was the result of a mucous membrane or eustachian tube problem. Severe sensori-neural hearing impairment occurred in less than 1%, and these were operations in which the oval window was opened. Unsatisfactory hearing was the cause of failure in 18%.