Type 2 ossiculoplasty: prognostic determination of hearing results by middle ear risk index

The aims of this study were to investigate the prognostic impact of middle ear risk index on the postoperative hearing results in cases with type 2 ossiculoplasty; to compare the middle ear risk index results among primary, staged, and revision cases; and to compare the results of the prostheses used in ossicular reconstruction.

Records of 293 patients who had canal wall up tympanomasteidectomy and type 2 ossiculoplasty due to chronic otitis media between November 1995 and November 2007 were reviewed retrospectively.

The mean preoperative air-bone gap was 32.6 dB, and it decreased to 15.2 dB after a mean follow-up period of 26.8 months postoperatively. The mean change of air-bone gap was 17.4 dB. Postoperative air-bone gap was 20 dB or less in 79% of the cases. The patients with dry perforations were in the low-risk group, and 91% of them had an air-bone gap of 20 dB or less. This value was 86% in the ones with intact malleus. The patients who had primary surgery were found in moderate risk group, whereas staged and revision groups were in the high-risk group. The air-bone gap was 20 dB or less in 84%, 78%, and 59%, respectively, of those groups. The difference between the primary and the revision groups reached a statistical significance.

We had the best ossicular reconstruction results with glass ionomer cement, whereas the worst results were obtained with allograft partial ossicular replacement prostheses. We determined that risk-reducing factors such as dry ear, minimal ossicular chain defect, and intact malleus were important to have successful results. The middle ear risk index is a valuable tool for the surgeon to judge the risks and the probability success of the procedure as well as to make a good patient selection.