[Spontaneous perforation of the membrane of the round window--a major cause of sudden deafness?].

In 1983, 45 out of 63 clinically treated patients with sudden hearing loss underwent an exploratory tympanotomy. In 27 cases (60%) a perforation of the round window membrane was found, whereas in 18 cases (40%) the round window membrane was intact and there was no perilymph fistula. From 1982 to the end of 1983 30 perforations of the round window membrane were found which are reported here, most of them being spontaneous perforations without any preceding trauma. Audiometrically, hearing losses were found ranging from medium to high degree. These included all types of hard hearing, such as loss of high or low tones and losses over all frequency ranges to total deafness. All patients complained of tinnitus. One-third of the patients with perforated membrane had dizziness or vertigo combined with disturbances of balance. Treatment consisted of sealing the round window membrane with a plug of fascia or periostium. When the patients were discharged, or shortly after their discharge, audiometry revealed normal hearing in three patients, improved hearing in 8 patients, no change in 14 patients, and further deterioration in 3 patients. In 8 patients with perforated membrane, the sudden hearing loss had occurred 1 to 12 months back and in 6 patients only 8 to 30 days ago. The study will continue, but we can already see from the present results that every sudden hearing loss should be examined for a possible spontaneous perforation of the round window membrane. For this reason, exploration of the round window should be done within the first few days. The study yields new knowledge of the pathogenesis of the sudden hearing loss.(ABSTRACT TRUNCATED AT 250 WORDS)