Impact of Trendelenburg angle on perioperative outcomes during gasless vNOTES surgeries: a retrospective comparative study

This retrospective cohort study compares perioperative outcomes of reduced Trendelenburg positioning (≤ 20°) versus conventional steep angles (≥ 30°) in gasless vNOTES for benign gynecologic conditions. Of 102 enrolled patients, 52 were assigned to the Low-Angle Group (Trendelenburg angle ≤ 20°, mean 20.1°) and 50 to the Steep-Angle Group (≥ 30°, mean 30.8°).”Primary outcomes included hemodynamics, airway pressure, and conversion rates; secondary outcomes encompassed operative metrics, anesthetic consumption, and 24-h visual analog scale (VAS) pain scores.Statistical analyses utilized longitudinal mixed models and t-tests. The estimation results showed that there is no statistically significant difference between the Low-Angle Group and the Steep-Angle Group in terms of HR, DBP, SBP and airway pressure at different time point during surgery. Airway pressures maintained strict proportionality to tidal volumes in both groups (12–17 cmH2O, p = 0.72).No significant differences were found between groups in conversion rates (4.0% vs. 4.3%, p = 0.319), operative/anesthesia duration, blood loss, complications, or most recovery indicators. Anesthetic consumption and VAS scores for shoulder pain/postoperative nausea and vomiting (PONV) were also similar at 2 h and 24 h. The Low-Angle Group had significantly lower 24-h abdominal pain VAS (0.46 ± 0.28 vs. 1.12 ± 0.42, p = 0.014), exceeding minimal clinically important difference (MCID) thresholds. Performing gasless vNOTES with ≤ 20° Trendelenburg achieves outcomes equivalent to ≥ 30°, including surgical exposure and safety, while significantly reducing postoperative abdominal pain. This challenges the need for routine steep positioning, establishing ≤ 20° as a viable patient-centered standard, offering equivalent efficacy with less discomfort. Further validation warranted.