Hemifacial spasm and nervus intermedius neuralgia associated with hyperfunction and hypofunction of the nervus intermedius

•Facial spasm with nervus intermedius neuralgia is few reported.•This is the first reported case involving hyperfunction and hypofunction symptoms of the nervus intermedius.•In this report the hyperfunction and hypofunction of nervus intermedius were successfully treated by microvascular decompression of root exit zone of seventh and eighth nerve. We have reported a case of a patient with hemifacial spasm (HFS) and nervus intermedius neuralgia associated with hyperfunction and hypofunction of the nervus intermedius. A 60-year-old man presented with a 6.5-year history of pain around the left eyelid and dry mouth. Three years prior, he noticed paroxysmal twitching of the left eyelid, and 1 year later, the spasm had extended to the entire left face. Simultaneously, he experienced left nose and left ear pain that was not aggravated by chewing, talking, or washing the face as well as nasal discharge. One year later, the facial spasms had aggregated. The patient was referred to our hospital for microvascular decompression (MVD) for HFS. Examination revealed normal findings, except severe HFS associated with slight left facial weakness. Three-dimensional magnetic resonance imaging (3D-MRI) showed neurovascular contact around the root exit zone (REZ) of the vestibulocochlear nerves by the posterior inferior cerebellar artery (PICA). MVD was performed via the left retrosigmoid approach, with interposition using a sponge made of urethane foam between the REZ of the facial nerve and PICA. The left nose and ear pain, dry eye, dry mouth, and nasal discharge were completely relieved 1 week after MVD. The HFS in the left face gradually improved and completely resolved 6 months after surgery. Although the association between HFS and nervus intermedius neuralgia has been previously reported, this is the first report of a case associated with symptoms of hyperfunction and hypofunction of the nervus intermedius successfully treated by MVD of the REZ of the seventh and eighth nerves.