Chronological Patterns of Long-Term Outcomes After Microvascular Decompression for Hemifacial Spasm Over 5 Years

Background: The postoperative course of hemifacial spasm (HFS) varies. We analyzed the clinical outcomes from 1 to ≥5 years after microvascular decompression (MVD) in patients with HFS. Methods: Between July 2004 and January 2015, 528 patients who were followed up for ≥5 years after MVD for HFS were included. We evaluated chronological patterns of clinical outcomes from 1 to ≥5 years. The outcomes at 2, 3, 4, and ≥5 years postoperatively were individually compared with those at 1 year postoperatively, and the relationships between clinical features, surgical findings, and outcomes over time were analyzed. Results: Eight groups were created according to the similarity in the pattern of clinical outcomes from 1 to ≥5 years postoperatively. Individual postoperative outcomes at 2–4 years were consistent with those at 1 year postoperatively, whereas postoperative outcomes at ≥5 years were not (P = 0.020). There was substantial to moderate agreement between the outcomes at 1 year and at 2–4 years postoperatively, but the agreement decreased over time. Patients without diabetes (P = 0.015), an intraoperative offending vessel without a vein (P = 0.005), and intraoperative discoloration of the facial nerve (P = 0.036) showed better outcomes at ≥5 years postoperatively. Conclusions: Long-term outcomes from 1 to ≥5 years after MVD in patients with HFS were diverse. Nondiabetes, intraoperative offending vessel without a vein, and intraoperative discoloration of the facial nerve were better prognostic factors for outcomes at ≥5 years postoperatively. It is advisable to consider these results when evaluating the long-term outcomes of this surgery.