Microvascular decompression for superior oblique myokymia: Case report

Background. Superior oblique myokymia (SOM) is a rare disorder in which the patient suffers episodic uniocular torsional eye movement associated with diplopia and oscillopsia. Although the pathophysiology has been narrowed down to erratic discharge of the trochlear nerve, yet the exact etiology remains unclear; a handful of cases have been described in association with an identifiable space occupying lesions or dural AV fistulae. Neurovascular compression theory has been postulated in the early 1980s and to our knowledge, very few reports exist in the literature accrediting this hypothesis in the pathogenesis of superior oblique myokymia. Case report. We report a case of successful resolution of severe medication refractory SOM following microvascular decompression of the trochlear nerve. The clinical response has been sustained for a follow-up period of 18 months to date. Conclusion. Microvascular decompression may be considered as a definitive and least destructive surgical option for the treatment of medication refractory superior oblique myokymia.