Factors Affecting Surgical Complexity of Microvascular Decompression for Hemifacial Spasm

The surgical complexity of microvascular decompression for hemifacial spasm was evaluated based on procedure duration. A retrospective analysis was performed on 127 patients who underwent microvascular decompression for hemifacial spasm. Surgical time was divided into 3 phases: craniotomy, microscopic procedure, and closure. Durations were analyzed by age, sex, body mass index, and whether mastoid air cells were opened. Microscopic procedure times were further assessed by mobilization of the anterior inferior cerebellar artery, posterior inferior cerebellar artery, and vertebral artery, as well as the number of arteries mobilized (single vs. multiple). Total surgical time was significantly shorter in patients aged ≥65 years (p = 0.015) and in women (p < 0.001). Sex was significantly associated with both craniotomy and closure durations (p < 0.001). Closure time was longer when mastoid air cells were opened (p = 0.013). Microscopic procedure time was also shorter in older patients (p = 0.001). No significant differences were observed between anterior inferior cerebellar artery- and posterior inferior cerebellar artery-related cases (p = 0.204 and p = 0.603). Vertebral artery-related cases tended to require longer durations, though not significantly (p = 0.085). Multiple artery mobilization showed a similar trend (p = 0.068). In 4 cases, microscopic time exceeded 100.5 mins due to overlapping factors such as bleeding, dense arachnoid, interfering perforators, and limited surgical space. Craniotomy and closure may be more complex in male patients with large mastoid air cells, and intradural complexity should be anticipated regardless of the culprit artery.