Deep Neuromuscular Blockade and a Low-Residue Diet for the Surgical Field in vNOTES Hysterectomy

vNOTES (vaginal natural orifice transluminal endoscopic surgery) hysterectomy is performed entirely through the vagina, with no abdominal incision. A clear surgical view is essential, and the main obstacle to the view is bowel falling into the pelvis. This randomized trial tests whether two simple measures improve the surgical field, individually or in combination: a preoperative low-residue diet for three days, and deeper intra-operative muscle relaxation (deep neuromuscular blockade). No group receives mechanical bowel preparation.

Using a 2×2 factorial design, participants are allocated equally (1:1:1:1) to one of four groups: (1) no diet with standard relaxation; (2) diet with standard relaxation; (3) no diet with deep relaxation; (4) diet with deep relaxation (the "bundle"). The surgical field is measured objectively: during a standardized window the carbon-dioxide insufflation pressure is lowered step by step, and 2-3 blinded assessors score the field from de-identified video. The primary outcome is the lowest pressure at which the field remains adequate; a lower pressure indicates an intrinsically better field.

The trial hypothesis is an interaction - that the combination achieves an adequate field at a meaningfully lower pressure than either measure alone. The final sample size is determined from an internal pilot. Secondary outcomes include the continuous field score, the need for an additional instrument to clear the field, postoperative nausea and vomiting, and routine operative outcomes.