Outcomes of surgical treatment for hemifacial spasm associated with the vertebral artery: severity of compression, indentation, and color change

Abstract

OBJECT: The object of surgical treatment for hemifacial spasm (HFS) is the exclusion of pulsatile neurovascular compression of the root exit zone (REZ). However, spasm persists transiently or permanently in some cases even after complete decompression. In particular, we mainly experience these results when the vertebral artery (VA) is the offender. Hence, we verified color changes of the nerve and indentations from within the operative field in HFS patients with the VA as the offender. So, we reviewed retrospectively the records of those patients who were treated with microvascular decompression (MVD) in order to assess the relationship between operative findings and clinical results. METHODS: A total of 232 patients with HFS associated with the VA were treated with MVD between January 1994 and January 2009 at our institution. The patients were classified into one of the following three categories based on compression severity: Group I, mild; Group II, moderate; Group III, severe. The patients were also classified into one of the following four categories based on the existence of indentation and discoloration of nerve VII: Group A (-/-), B (+/-), C (-/+), or D (+/+). RESULTS: A total of 94.2% and 96.6% of the patients in Groups I and II, respectively, had improved to grades I-II at the last follow-up. The surgical outcomes of Group III were slightly poorer than those of Groups I and II. Group A showed the poorest outcomes with 60% of the patients classified as grades III-IV. In Group B, 98.4% of the patients showed a marked improvement and Groups C and D showed relatively poor outcomes compared with those of Group B. CONCLUSIONS: Severe deviations and color changes of the facial nerves may be the risk factors for poor surgical outcomes. Future studies with larger sample sizes and investigations of the pathophysiology underlying these findings are needed.