Association Between Preoperative MRI-Based Pelvic Anatomy and Phase-Specific Operative Time in vNOTES Hysterectomy: A Retrospective Study.

BACKGROUND: Predicting surgical difficulty in vNOTES hysterectomy remains challenging. METHODS: We retrospectively analyzed 49 patients who underwent vNOTES hysterectomy between April 2023 and April 2026. Cases with pelvic organ prolapse and cases with incomplete data were excluded, resulting in 42 evaluable patients. At our institution, patients suspected preoperatively of cul-de-sac obliteration were not considered candidates for vNOTES hysterectomy. The procedure was divided into three phases: transvaginal access, laparoscopic, and closure. Pelvic anatomical parameters (PCL, H line, M line, and H/PCL ratio) and clinical variables were evaluated using preoperative resting MRI and perioperative surgical records. RESULTS: The H line showed significant negative correlations with operative time in both the transvaginal phase (ρ = -0.345, p = 0.025) and laparoscopic phase (ρ = -0.413, p = 0.007), whereas no significant correlation was observed in the closure phase. In multivariate analysis, the H line showed a consistent negative association with operative time, although statistical significance was not reached. CONCLUSION: Pelvic anatomy, particularly the H line, is associated with operative difficulty in vNOTES hysterectomy. Resting MRI provides a practical and generalizable assessment method. These findings may aid preoperative evaluation and improve surgical planning and patient selection.