IONOMER-BASED CEMENT AS A BONE SUBSTITUTE IN RECONSTRUCTIVE MIDDLE-EAR SURGERY

Animal experiments with microbiologic examinations and studies in cell cultures have shown that ionomer cement is a biocompatible and biosta ble bone replacement material in the head and neck region. Clinical an d functional results of its use in the human middle ear have proven to be satisfactory during a maximal period of 2.5 years observation. The present trial was continued in order to determine the long-term behav ior of ionomer cement (lonos partial and total ossicles) after reconst ruction of the ossicular chain. The ossicular chain was reconstructed in 343 cases and included various losses of one or more of the ossicle s (i.e., incus, incus and malleus, incus and stapes superstructure, an d malleus, incus and stapes superstructure). Follow-up extended over a maximum period of 5.5 years. Patients were examined under a surgical microscope and a pure-tone audiogram was performed at regular interval s. Clinical and audiological results were obtained 3 months postoperat ively in all reconstructive procedures performed (partial and total os sicular replacement prostheses). These were mainly stable but revision surgery was necessary in 9% of the cases. In 5% the pros thesis was d isplaced and in 3% the prosthesis had partially migrated through the e ardrum. Complete rejection of the implants was observed in the course of infections in 1% of the cases. Ionomer cement as a bone replacement material was found to have all required criteria for its use in the m iddle ear (biocompatibility, biostability, stable audiologic results a nd easy workability). These findings show that ionomer cement can be r ecommended in all cases of ossicular reconstruction.