Chronologic analysis of symptomatic change following microvascular decompression for hemifacial spasm: value for predicting midterm outcome

The objectives of this study are to categorize the patterns of symptomatic change and to chronologically analyze them. From January 2004 to February 2006, microvascular decompression was performed on 236 consecutive patients. Follow-up time was at least over 1 year (mean, 17.1 months). We categorized the postoperative courses into five different groups according to the similarity of the temporal changes of the residual symptoms. The symptomatic change during each follow-up interval was chronologically analyzed among five different groups. The five improvement patterns included group A (immediate recovery without relapse), group B (temporary relapse followed by cure), group C (slow but steady improvement that leads to cure after one or more months), group D (recurrence with sustained symptoms), and group E (no improvement or improvement to some extent that does not lead to cure). The symptomatic change in the successful groups (groups A, B, and C) differed from that in the unsatisfactory groups (groups D and E), especially during the follow-up interval between postoperative 3 weeks and 3 months (p = 0.014). This finding was true with (p = 0.029) or without (p = 0.015) the relapse curve. Therefore, we can predict the postoperative result as early as 3 months after the surgery. Overall cure rate in this series (93.2%) was nearly correspondent to the estimated cure rate at the first postoperative year (93.4%). Postoperative 3 months can be the most efficient and earliest time to predict the postoperative result.