Cutting the chorda tympani: not just a matter of taste.

ABSTRACT

INTRODUCTION: Chorda tympani injury as a complication of middle-ear surgery has been extensively studied with regard to its effects upon taste. However, the chorda tympani also carries parasympathetic fibres to the salivary glands of the oral cavity. To date, little has been reported about the effect of chorda tympani section upon salivary function. SETTING: Tertiary care centre. MATERIAL AND METHODS: We report a case series of three patients with bilateral chorda tympani lesions. Chorda tympani function was assessed using 'taste strips' and unstimulated sialometry. A careful history of oral symptoms was taken. RESULTS: All patients showed transient or permanent bilateral ageusia of the anterior two-thirds of the tongue, and a decreased resting salivary flow rate. In addition, all patients suffered from transient or persistent, distressing xerostomia. CONCLUSION: Taste disorders may occur after middle-ear surgery but they are mostly transient, even when the chorda tympani nerves are sectioned bilaterally. In contrast, bilateral chorda tympani lesions may lead to severe, persistent and distressing xerostomia. Based on this neglected aspect of chorda tympani function, we emphasise the importance of preserving the chorda tympani whenever possible.