Hemifacial Spasm Caused by a Vein: A Case Report.

Hemifacial spasm (HFS) caused by a venous offender is rare, and its clinical course and optimal surgical strategy are unclear. A case of 57-year-old male who had an HFS caused by a venous offender is described in this report. Frontalis, orbicularis oculi, orbicularis oris, and mentalis muscles were involved while his platysma muscle showed no spasm. He was treated successfully with microvascular decompression using Teflon felt and 12 months outcome was excellent without any complications. Lateral spread response was not observed in the facial electromyography during the whole operation. Adequate visualization of the facial nerve root exit zone and meticulous exploration for offenders are necessary to avoid surgical failure and reoperation.