Clinical Outcome After Microvascular Decompression According to the Progression Rates of Hemifacial Spasm

OBJECTIVE: The progression rate for clinical manifestations in hemifacial spasm (HFS) varies; however, little is known about the factors contributing to this. The purpose of this study was to identify independent factors affecting the rate of symptom progression and to evaluate clinical outcomes according to progression rates. METHODS: The study enrolled 1335 patients who underwent microvascular decompression for HFS between July 2004 and January 2015. We assessed detailed history, clinical manifestations, and outcomes. Based on the duration and severity of symptoms, patients were classified into rapidly progressive and slowly progressive groups. We identified predisposing factors affecting the differences between the 2 groups and evaluated the clinical outcome in each group. RESULTS: Of 1335 patients with HFS, 825 (61.8%) were classified as rapidly progressive, and 510 (38.2%) were classified as slowly progressive. In univariable and multivariable analyses, younger age at surgery, older age at symptom onset, and absence of intraoperative facial nerve indentation were significant predisposing factors for rapid progression. The rapidly progressive group had worse outcomes than the slowly progressive group following microvascular decompression. CONCLUSIONS: In this study, patients with rapidly progressive HFS had worse clinical outcomes. Therefore, patients with rapidly progressive symptoms should be warned in advance that the prognosis may be worse after microvascular decompression. This study is also useful to understand the differences in symptom progression rates in HFS in order to inform patients about symptom progression.