Impact of previous decompression technique on operative complexity in redo microvascular decompression for hemifacial spasm

Persistent or recurrent hemifacial spasm (HFS) after microvascular decompression (MVD) occasionally requires redo surgery. Although transposition and interposition techniques provide comparable outcomes in primary MVD, their influence on the operative characteristics of redo MVD remains unclear. This study investigated the impact of the previous decompression technique on operative complexity and intraoperative findings.

We retrospectively reviewed 23 patients who underwent redo MVD for HFS between 2014 and 2024. Patients were classified according to the decompression technique used at the previous surgery: transposition (n = 16) or interposition (n = 7). Operative time, intraoperative findings, surgical outcomes, and postoperative complications were compared between the groups.

Total operative time was significantly shorter in the transposition group than in the interposition group (272.4 vs. 342.6 min, P = 0.028). Microsurgical time was also significantly shorter in the transposition group (145.9 vs. 216.3 min, P = 0.021), whereas craniotomy and closure times did not differ significantly. In the transposition group, vascular contact related to positional or configurational changes was the predominant finding, whereas prosthesis-related compression and adhesions around neurovascular structures were more common in the interposition group. Effective outcomes and complication rates were comparable between the groups.

Redo MVD following a previous transposition procedure was associated with shorter operative and microsurgical times than redo MVD following interposition. These differences appeared to reflect distinct intraoperative pathology and technical demands during reoperation. The initial decompression technique may influence both the intraoperative pathology and surgical complexity of subsequent redo MVD.