RESUMEN
We report a patient suffering from delayed facial palsy after microvascular decompression (MVD) for hemifacial spasm, in whom the pathogenesis was proved. A 56-year-old man with a left hemifacial spasm was admitted to our hospital. Preoperative MR imaging showed that the left anterior inferior cerebellar artery (AICA) was compressing the left facial nerve. The causative vessel was defined as AICA during surgery, and MVD was performed successfully. Seven days later, the patient showed severe left facial palsy. Serum antibody of varicella-zoster virus (VZV) was increased, and Gd enhanced MR imaging demonstrated an enhancement of a geniculate ganglion of the left facial nerve, indicating inflammation. These findings suggested that delayed facial palsy after MVD was caused by a re-activation of VZV. The facial palsy disappeared completely over a period of nine months.