Middle ear cholesteatomas in temporal bones with low middle fossa tegmen

Temporal bone with low middle fossa tegmen is one of the causative factors of troublesome complications in cholesteatoma patients.One hundred and thirty-five consecutive patients with acquired cholesteatoma, who visited Mitsui Memorial Hospital between 1993 and 2004 for ear surgery, were studied with a retrospective case series study design (75 males and 60 females, age ranging from 12 to 75 years old (mean 49), total 144 ears: 105 attic type and 39 pars tensa type).Thirteeen cases were with low middle fossa tegmen, 33 cases had inner ear fistula, and facial nerve exposure was seen in 23 cases. Although there was no statistically significant difference compared to cases with normal attic space, the risk of complications was twice as high in cases with low middle fossa tegmen: inner ear fistula was seen in 38% (5/13 ears) and facial nerve exposure was seen in 31% (4/13 ears). We conclude that extra attention and fine procedure are necessary in mastoidectomy in such cases.