Intraoperative assessment of perilymphatic fistulas with intrathecal administration of fluorescein.

Abstract

Assessment of perilymphatic fistulas remains a diagnostic problem. Because of a lack of reliable clinical tests, exploratory tympanotomy is necessary to detect membrane leaks in the middle ear. To improve objectivity in the intraoperative visualization of perilymphatic fistulas, we used intrathecal fluorescein for perilymph staining to increase the sensitivity and specificity of diagnosis of perilymphatic fistulas. Prospective study in the setting of a tertiary, referral, and academic center. Twenty-eight patients with suspected traumatic, idiopathic, iatrogenic, or inflammatory perilymphatic fistulas were admitted for exploratory tympanoendoscopy for perilymphatic fistula detection. Twenty-five to 100 mg sodium fluorescein 10%, diluted with cerebrospinal fluid, was administered by lumbar puncture 2.5 to 23.5 hours before tympanoendoscopy. The oval and round window niches were microscopically and endoscopically observed with white and blue light, using specific filters. In two patients (7%), obvious fluorescence was detected behind the round window membrane with blue light. Direct observation of perilymph in stapedectomy and in semicircular canal fistula revealed no staining. Neurological complications of intrathecal fluorescein, as reported by other authors, were not observed. Probably because of a different patency of the cochlear aqueduct, intrathecal fluorescein for intraoperative detection of perilymphatic fistula resulted in a significant perilymph staining in only a few patients. Considering the possible complications of this method, we would not recommend it for routine evaluation of perilymphatic fistula.