“Lateral spreads” refers to pathological electrophysiological muscle activity, such as that which may be observed in patients with hemifacial spasm.
Hemifacial spasm
Intraoperative monitoring of the lateral spread response in patients undergoing surgery for a neurovascular conflict associated with Hemifacial spasm has high specificity but limited sensitivity for predicting surgical success. Intraoperatively persistent lateral spreads indicate persistent postoperative spasms. Therefore, in cases in which the intraoperative lateral spreads persist, the course of the Facial nerve should be thoroughly reexamined after decompression before closure[^1].