A significant correlation between delayed cure after microvascular decompression and positive response to preoperative anticonvulsant therapy in patients with hemifacial spasm

Although microvascular decompression (MVD) is a reliable treatment for hemifacial spasm (HFS), the postoperative course is varied. We retrospectively analyzed the resolution pattern of the spasm and specified predictors for delayed cure after MVD. This study included 114 consecutive patients with typical HFS. All of them were followed up for at least 1 year after operation. Patients were divided into three groups depending on the postoperative course: immediate cure, delayed cure, and failure. To identify the predictive factors for delayed cure after MVD, logistic regression analyses were applied using candidate clinical factors, such as duration of symptom, the tendency of the spasm, preoperative medical treatment, and offending vessels. Among the 114 patients, 107 patients were cured. For those cured, 65 patients were classified as immediate cure and 42 patients were classified as delayed cure. Cumulative spasm-free rates after 1 week, 1 month, and 3 months after MVD were 70, 88, and 97 %, respectively. No predictive factors between the cured and failure groups were observed. According to multivariate analysis, preoperative anticonvulsant therapy was found to be the sole significant predictive factor for delayed cure after MVD (p = 0.025). A significant correlation between delayed cure and preoperative anticonvulsant therapy was found in our study, which suggests that hyperexcitation of the facial nucleus plays an important role in pathogenesis of delayed cure. Therefore, if a patient demonstrating a positive response to preoperative anticonvulsant therapy showed a persistent spasm after MVD, reoperation should be delayed for at least 3 months after the initial operation.