Factors associated with persistent abnormal muscle responses in microvascular decompression for hemifacial spasm and prognostic analysis

Risk factors for the persistence of AMRs can be used to predict the probability of persistent intraoperative AMRs. An intraoperative AMR that persists despite having a low preoperative predicted probability may indicate inadequate facial nerve decompression or undetected offending vessels, requiring either additional surgical exploration or transposition of the offending vessels. Conversely, when an AMR persists in the context of a high preoperative predicted probability, the MVD procedure can be safely terminated after confirming adequate decompression to minimize surgical complications. Patients with persistent AMRs may experience delayed recovery, with symptom relief potentially taking 3 months. If symptoms persist without improvement for 6 months to a year, a second surgery can be considered.