Predicting Surgical View Obstruction During Retrosigmoid Microvascular Decompression for Trigeminal Neuralgia

Abstract To identify the multifactorial predictors of surgical view obstruction (SVO) during microvascular decompression (MVD) for trigeminal neuralgia and to propose a standardized, criterion-based classification system to guide preoperative decision-making. We retrospectively reviewed 95 consecutive adult patients with classical trigeminal neuralgia who underwent retrosigmoid MVD between 2015 and 2024. All procedures were performed by a single senior surgeon using standard retrosigmoid techniques in various operative positions. SVO was defined using a criterion-based, stepwise intraoperative framework based on failure of standard exposure maneuvers, with SVO recorded when additional advanced techniques, including suprameatal tubercle (SMT) drilling, were required. Descriptive and exploratory statistical analyses were performed to support operative observations. Among 95 patients undergoing retrosigmoid MVD for classical trigeminal neuralgia, SVO requiring bone drilling was encountered in 15 cases (15.8%). SVO was more frequently observed in cases with a prominent SMT, dolichoectatic vertebrobasilar artery, and constrained operative positioning, especially sitting position, and was associated with increased operative time reflecting greater technical complexity. Despite exposure difficulty, short-term postoperative pain relief was comparable between patients with and without SVO, indicating that adequate decompression was achieved once visualization was optimized. SVO is a dynamic intraoperative phenomenon driven by the interplay of bony anatomy, vascular pathology, and patient positioning. Awareness of the “triple threat”—prominent SMT, dolichoectasia, and limited positioning—enables surgeons to anticipate exposure challenges and tailor operative strategies accordingly.