Microvascular decompression for hemifacial spasm: analyses of operative complications in 1582 consecutive patients

Background: Microvascular decompression is the most reliable treatment for HFS, but it may cause complications. The aim was to identify factors affecting the prognosis after MVD and to establish appropriate means to reduce complications. Method: We retrospectively reviewed 1524 patients with HFS who underwent MVD and were followed for more than 6 months since January 1987. The mean follow-up duration was 30.9 months (6-197 months). Results: The effect of MVD was satisfying (excellent or good) in 94.6% (n = 1442). The failure and recurrence rates were 2.1% (n = 32) and 0.4% (n = 6), respectively. Postoperative complications were noted in 545 (35.8%) patients. Among them, facial palsy, hearing deficit, and low cranial nerve palsies were found in 18.6% (n = 283), 7.2% (n = 109), and 2.8% (n = 43), respectively. However, permanent facial weakness, hearing deficit, and lower cranial nerve palsies such as hoarseness and dysphagia were encountered in 1.2% (n = 18), 2.1% (n = 32), and 0.1% (n = 2), respectively. The more immediate and severe the facial palsy was, the more permanent it remained, with statistical significance (P < .05). There was a trend that the more immediate and severe the hearing deficit was, the more permanent the deficit remained, without statistical significance (P = .673). Conclusion: Early (occurrence within 24 hours after operation) and severe cranial nerve deficits, including facial, hearing, and lower cranial nerve deficits after MVD, entail the risk to stay permanent.