The effect of chorda tympani section on ipsilateral and contralateral salivary secretion and taste in man.

Bilateral chorda tympani section is an accepted treatment for troublesome sialorrhoea. Nevertheless the effects of this operation have been poorly studied. Twenty patients were studied with unilateral chorda tympani section and a healthy contralateral ear. The effects on ipsilateral and contralateral stimulated submandibular and parotid flow and taste recognition and detection thresholds were measured. Stimulated submandibular flow accounted for only 27% of the total salivary flow. Chorda tympani section had no effect on submandibular flow in seven patients and only reduced submandibular flow by approximately 54% in the remaining 13 patients. No significant effect was observed on ipsilateral parotid flow rate. Electrogustometric taste detection thresholds were more than twice the accepted upper limit of normal on the lesioned side and taste recognition thresholds were also markedly abnormal. Chorda tympani section alone is a poor method of reducing stimulated salivary flow.