Treatment of labyrinthine fistula with interruption of the semicircular canals.

Evaluation of postoperative hearing acuity and equilibrium was performed in eight patients with labyrinthine fistula caused by cholesteatoma, in which at least one of the semicircular canals (five cases, lateral; one case, superior; one case, posterior; and one case, both lateral and superior) was interrupted during eradication of the matrix and granulations from the semicircular canals. The interrupted semicircular canals were obliterated firmly with autologous materials such as fascia, perichondrium, bone chips, and cartilage. The observation period ranged from 9 months to 3.3 years. Postoperative hearing was unaltered or improved in seven patients, and decreased by 12 dB in one patient. Postoperative disequilibrium lasting more than 2 weeks was experienced in two patients and disappeared at the second and fifth postoperative months, respectively. Relief from fistula symptoms was complete after surgery, indicating adequacy of this procedure in one-stage open-method tympanoplasty. The present study indicates that manipulation of the semicircular canal with awareness can be conducted without damaging the cochlear function, and that the treatment of labyrinthine fistulas should be performed very carefully but not so conservatively as to lead to future problems. In some cases of deep fistulas of the semicircular canals, interruption and/or obliteration of the semicircular canals can be the most proper procedure.