Intraoperative findings of revision canal wall-down tympanomastoid surgery

CONCLUSION: Chronically discharging mastoid cavities had well-defined technical faults from previous surgery. Identifying and eliminating these errors during revision canal wall-down (CWD) tympanomastoidectomy converted troublesome mastoid cavities into safe ears in 84% of cases. OBJECTIVE: To assess intraoperative findings of revision CWD tympanomastoidectomy to determine the most common causes of failure of previous surgery. The short-term results of revision surgery after a 12-month follow-up period were analyzed. METHODS: The study group consisted of 50 consecutive patients, 27 males and 23 females, aged 7-63 years (mean 34 ± 17 years) undergoing revision CWD tympanomastoidectomy due to persistently discharging mastoid cavities. The outcome of revision surgery was measured semi-quantitatively using a grading system. RESULTS: The most common causes for failure of previous surgery were persistent mastoid cells in the tegmental, sinodural angle, and the retrolabyrinthine, retrofacial, and mastoid tip regions (100%); the bony overhangs at the edges of the mastoid cavity and the high facial ridge (98%); inadequately narrow meatus (84%); recurrent or residual cholesteatoma (46%); and remaining malleus head (40%). Revision surgery included elimination of all encountered limitations followed by mastoid cavity obliteration in about two-thirds of cases. Hearing restoration was done in only 34% of ears. In the remaining cases, intact ossicular chain (6%), existing sufficient previous reconstruction (22%) or impossible situation for reconstruction (38%) was found.