How I do it: microvascular decompression for hemifacial spasm using an inferior ventrolateral brainstem approach

Hemifacial spasm is commonly caused by a vascular compression of the facial nerve at its root exit zone (REZ), at brainstem. Microvascular decompression provides long-term cure in approximately 90% of the patients (delayed in one-third). Based on more than three hundred procedures, the authors advocate an inferior ventro-lateral brainstem approach. This trajectory optimizes access to the REZ, while minimizing traction on the cerebellum, the cochleo-vestibular nerve, and the labyrinthine artery. Decompression should be achieved by transposing the offending vessel (PICA, AICA, either alone or associated with a vertebro-basilar- dolichoectatic artery). Monitoring of brainstem auditory evoked potentials can be useful during learning curve.