Pathogenesis and Treatment of Hemifacial Spasm

Hemifacial spasm can be cured by microvascular decompression (MVD) operations of the root exit zone of the facial nerve. This fact was the basis for the (“ephaptic”) hypothesis stating that the anatomical location of the pathology that generates the signs of HFS, spasm in the mimic muscle on one side of the face and synkinesis, was the root exit zone of the facial nerve. However, later intracranial recording from the facial nerve provided strong experimental support of a different hypothesis about the pathology of HFS, namely, that the anatomical location of the pathology is the facial motonucleus.