Fully Endoscopic Microvascular Decompression of the Trochlear Nerve for Treatment of Medically Refractory Superior Oblique Myokymia

Introduction: Superior oblique myokymia (SOM) is an ocular movement disorder that causes diplopia and oscillopsia, particularly with down gaze, secondary to involuntary, rhythmic contractions of the superior oblique muscle. Multiple reports have implicated vascular compression of the trochlear nerve by the superior cerebellar artery in the pathogenesis of SOM For these cases, microvascular decompression (MVD) of the trochlear nerve may represent a low-morbidity, definitive surgical intervention

Methods: We describe, to our knowledge, the first report of fully endoscopic MVD of the trochlear nerve in a patient with SOM. We have a stepwise operative video showcasing our technique.

Results: A 51-year-old female presented with multiple years of intermittent, “jumpy” and “shimmering” visual disturbances. She was diagnosed with SOM. Magnetic resonance imaging showed right trochlear nerve compression within the peri-mesencephalic cistern between the free edge of the right tentorial leaflet and the right superior cerebellar artery. She underwent endoscopic microvascular decompression of the trochlear nerve with complete resolution of symptoms.

Conclusion : Endoscopic MVD of the trochlear nerve is technically feasible and may be used to treat medically refractory SOM.