Comparison of transposition and interposition methods in microvascular decompression for hemifacial spasm: an analysis of 109 cases performed by a single surgeon in a single-center retrospective study

Microvascular decompression (MVD), the standard surgical approach for hemifacial spasm (HFS), can be divided into the interposition and transposition methods. Although the risk of HFS recurrence following interposition has been reported, there is limited data comparing long-term outcomes between both methods performed by a single surgeon. This study aimed to investigate the efficacy of MVD techniques on HFS by comparing surgical outcomes performed by a single surgeon in a single-center setting.

A total of 109 patients who underwent MVD were analyzed and divided into the transposition (86 patients) and interposition (23 patients) groups. Postoperative outcomes at 1 month and 1 year were assessed and compared, including rates of spasm relief, complications, and recurrence.

Outcome assessment revealed higher rates of early spasm relief in the interposition group (66.3% vs. 100%, transposition vs. interposition, respectively, p = 0.0004), although spasm relief at 1-year postoperatively was comparable between the two groups (84.9% vs. 95.7%, transposition vs. interposition, respectively, p = 0.2929). No significant differences were observed in complication and recurrence rates. Kaplan–Meier analysis demonstrated no significant differences in the duration of spasm resolution by MVD method (p = 0.4347, log-rank test).

This study shows that both the transposition (Surgicel® and fibrin glue) and interposition (sponge) methods were excellent surgical techniques. The interposition method may achieve earlier spasm resolution compared to the transposition method.