Intraoperative findings in revision canal wall down mastoidectomy.

Effective canal wall down mastoid surgery requires attention to certain key principles. We reviewed all cases requiring revision surgery at the Royal Victoria Eye and Ear Hospital over a 6 year period 1999-2004. Intraoperative findings which contributed to the need for revision surgery were identified. During this 6 year period 291 canal wall down mastoidectomies were performed. Thirty-seven were revision procedures. Nineteen (51%) cases were found to have recurrent or residual cholesteatoma. Sixteen (43%) cases had a high facial ridge, thirteen (35%) cases had an open middle ear. Nine (24%) cases had an inadequate meatus, 2 (5%) cases had a cavity sump. This study illustrated that a high facial ridge, an open middle ear segment, an inadequate meatoplasty and recurrent cholesteatoma were common intraoperative findings in this revision group. Eighty-nine percent of revision cases had dry, healed and safe cavities on follow up. Poor performance of the open technique is the most important factor in failure.