Early Risk Stratification and Time-to-Cure Analysis in Patients with Residual Hemifacial Spasm After Microvascular Decompression

Background/Objectives: Microvascular decompression (MVD) is an effective treatment for hemifacial spasm (HFS), but some patients have residual spasms after surgery. Some later achieve delayed cure, whereas others have persistent HFS, making reoperation planning difficult. This study aimed to develop a prediction model for early risk stratification in patients with residual HFS after MVD. Methods: We retrospectively analyzed 500 consecutive patients with primary HFS who underwent MVD between November 2021 and August 2023. Among them, 140 patients with residual HFS at 24 h postoperatively were included. Clinical variables, intraoperative abnormal muscle response, Cohen grade at 24 h after surgery (Cohen-post), and Immediate Subjective Improvement Rate (ISIR) were collected. A multivariable logistic regression model was developed and presented as a nomogram, with bootstrap internal validation. Cox regression and Kaplan–Meier analyses were used to assess time to cure. Results: Mean follow-up was 21.9 months. Delayed cure occurred in 102 patients (72.9%), whereas 38 (27.1%) had persistent HFS. The final model included ISIR, Cohen-post, and offending artery status. The nomogram showed good discrimination (area under the curve 0.901). Patients with higher ISIR and lower Cohen-post recovered faster. Among patients with delayed cure, median time to cure was 30 days, and 95% achieved cure within 300 days after surgery. Conclusions: In patients with residual HFS at 24 h after MVD, a nomogram incorporating ISIR, Cohen-post, and offending artery status may help distinguish delayed cure from persistent HFS and may provide useful information on the likelihood of further recovery.