Cupulolithiasis and posterior ampullary nerve transection.

Schuknecht's description of a degenerated otoconial mass embedded in the cupula of the posterior canal crista of the downmost ear in the Hallpike test has been termed cupulolithiasis to reflect the pathophysiology in the syndrome described by Barany. The hypothesis that the otoconial mass renders the cupula of the posterior canal gravity-sensitive has received considerable experimental and clinical support. Clinical support is provided here by the observation that complete relief of the paroxysmal positional vertigo followed transection of the posterior ampullary nerve (singular nerve) in 31 ears of 29 patients complaining of chronic cupulolithiasis. Two patients in the series exhibited bilateral cupulolithiasis and were relieved by sequential bilateral singular neurectomies. Twenty-seven patients were relieved by unilateral singular neurectomy. Although there were three instances of sensorineural hearing loss following surgery in the first 15 patients, no hearing loss has been observed following surgery in the last 16 operations. This low incidence of sensorineural hearing loss has resulted from modifications in surgical technique.