[Labyrinthine fistulae and cholesteatoma]

The case notes of 33 patients with labyrinthine fistulae have been studied; they have been found in 10% of cholesteatomas. The usual site is the lateral semicircular canal. Only 17 patients experienced vertigo, 2 had total deafness, and 14 others had a mixed deafness. Scanning with fine cuts in both the axial and coronal planes demonstrates the lesion definitively in 70% of cases, but the fistula may be discovered only at operation, either in the lateral semicircular canal, or especially at the level of the oval window (5 cases). The authors usually use the closed technique (26 cases), and always seek to remove the matrix in its entirety, followed by the use of bone powder to close the fistula. In 2 patients there was a loss of hearing on bone conduction at 4 and 8 KHz, and only one had total loss of hearing. No patients had vertigo persisting after 6 months. The indications and results are compared with those found in the literature. It now seems unusual to experience postoperative sensory-neural hearing loss provided that the presence of a fistula is recognised early on, and that the covering of squamous epithelium is removed completely atraumatically at the last part of the operation.