[Labyrinthine fistula caused by chronic suppurative otitis media]

To study the clinical feature and surgical management of labyrinthine fistula caused by chronic suppurative otitis media (CSOM).

A retrospective study of 450 patients with CSOM who underwent radical mastoidectomy between the years 1992 to 1999 in Department of Otolaryngology, Xijing Hospital was conducted.

20 patients (4.4%) with labyrinthine fistula caused by CSOM were found. The average history of ear drainage was 22 years, 18 patients (90%) had subjective hearing loss, and 13 patients (65%) had dizziness. The fistula test was positive in 9 patients (45%). 2 patients had anacusis in the affected ear. The preoperative pure tone average for bone conduction thresholds was less than 30 dB in 11 patients, between 31 and 50dB in 3 patients, and more than 51 dB in 4 patients. The ears with a positive fistula test had worse preoperative hearing than those with negative test (P < 0.01). The fistula was detected by CT in 2 of 9 patients. Cholesteatoma was present in 18 patients (90%) and granulation tissue was present in 2 patients (10%). The lateral semicircular canal was the site of labyrinthine fistula. The lesion at the site of fistula was completely removed in 17 patients and exteriorized in the remaining 3.

There are no reliable methods at present for preoperative diagnosis of labyrinthine fistula, ultimately, the most reliable way to identify a fistula is during surgery. The method of manipulation of labyrinthine fistula is based on the concrete conditions of fistula and patient.