Fig. 1.

The CMAP amplitude ratios of the affected and unaffected facial nerves in patients with HFS were measured four times, pre- and post-MVD surgery. The CMAP amplitude ratios were 95.7% at preoperation and 90.9% at 1 week, 95.6% at 1 month, and 96.0% at 1 year after MVD in the HFS patients without PFW; 85.3% at preoperation and 70.3% at 1 week, 82.5% at 1 month, and 85.5% at 1 year after surgery in the patients with PFW. The error bars represent standard error. CMAP: compound muscle action potential, HFS: hemifacial spasm, MVD: microvascular decompression, PFW: preoperative facial weakness.