Utility of intraoperative electromyography in microvascular decompression for hemifacial spasm: a meta-analysis

Object. In this paper, the authors' goal was to determine the utility of monitoring the abnormal muscle response (AMR) or lateral spread during microvascular decompression surgery for hemifacial spasm. Methods. The authors' experience with AMR as well as the data available in the English-language literature regarding resolution or persistence of AMR and the resolution or persistence of hemifacial spasm at follow-up was pooled and subjected to a meta-analysis. Results. The pooled OR revealed by the meta-analysis was 4.2 (95% CI 2.7-6.7). The chance of a cure if the AMR was abolished during surgery was 4.2 times greater than if the lateral spread persisted. Conclusions. The AMR should be monitored routinely in the operating room, and surgical decision-making in the operating room should be augmented by the AMR. (DOI: 10.3171/2009.8.FOCUS09142)