[Hearing results after anterior tympanotomy in cholesteatoma surgery]

Between 1987 and 1993, 71 ears of attic type cholesteatoma and 20 ears of adhesive type were operated on using the intact canal wall technique combined with anterior tympanotomy. Pre- and postoperative pure tone hearing after the surgery were analyzed, especially to determine whether anterior tympanotomy is harmful to the inner ear. Mean values of 500, 1000 and 2000Hz of air conduction threshold immediately, before and about 1 year after the operation were compared. In attic cholesteatoma, type 1, type 3, and type 4 of ossiculoplasty revealed significant improvement of 8.4dB, 9.3dB, and 8.0dB respectively. In adhesive cholesteatoma, results obtained were 8.4dB, 0.8dB, and -3.0dB. Differences between pre- and postoperative bone conduction threshold at 4000Hz were 1.5dB in type 1, 1.3dB in type 3, and 5.0dB in type 4 in attic cholesteatoma. Those in adhesive cholesteatoma were -2.5dB, -0.2dB, and -10.0dB respectively. From the results obtained, we concluded that (1) our results were satisfactory with regards to hearing ability following all types of ossiculoplasty in attic cholesteatoma and in type 1 in adhesive cholesteatoma, (2) anterior tympanotomy itself is not a harmful procedure to the inner ear in both types of cholesteatoma, (3) an increase in bone threshold in adhesive cholesteatoma is due to the surgical procedure at the stapes and/or the oval window.