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.
Adult women (aged 18 years or older) scheduled for hysterectomy for a benign (non-cancer) indication.
Judged suitable for the vNOTES approach by the operating surgeon.
Able to understand the study and provide written informed consent.
Suspected or known gynaecological malignancy.
Conditions expected to make the approach or the field assessment non-standard (e.g., anticipated dense pelvic adhesions or severe endometriosis, a contraindication to vNOTES, or an obliterated cul-de-sac).
Any medical reason why deep neuromuscular blockade or sugammadex would be unsafe (defined with the anaesthesia team).
Any medical reason why a low-residue diet would be unsuitable.
Factorial
Deep Neuromuscular Blockade (NMB)
DrugRocuronium by continuous infusion to maintain profound relaxation (no train-of-four twitches; post-tetanic count 1-2) until the end of the field measurement and surgery; reversed with sugammadex and confirmation of full recovery (train-of-four ratio ≥ 0.9) before extubation. Cross-reference to arms: Arms 3, 4
Standard (moderate) neuromuscular blockade
DrugRocuronium by intermittent bolus to maintain a train-of-four count of 1-2 (usual care); reversed with sugammadex and confirmation of full recovery (train-of-four ratio ≥ 0.9) before extubation. Cross-reference to arms: Arms 1, 2
Preoperative low-residue diet
Other interventionA low-residue diet (less than 10 g dietary fibre per day) for the three days before surgery, with standardised food lists and a patient information sheet. This is a dietary measure, not a laxative; no mechanical bowel preparation is used. Cross-reference to arms: Arms 2, 4
Lowest CO₂ insufflation pressure at which the surgical field is adequate (blinded Transvaginal Natural Orifice Endoluminal Surgery - Objectiveisual Index: vNOTES-OVI ≥ 1)
During a standardized intra-operative window, insufflation pressure is lowered from 12 mmHg to 6 mmHg in 1 mmHg steps, with a 60-second equilibration at each step; at each step a 3-second de-identified video clip is scored by 2-3 blinded assessors with the vNOTES-OVI (0/1/2). The consensus (median) score yields, per participant, the lowest pressure at which the field is adequate (OVI ≥ 1). Lower pressure indicates a better field.
Continuous surgical-field score (vNOTES-OVI)
Blinded vNOTES-OVI (0/1/2) at each insufflation-pressure step, analysed as a threshold-free ordinal/continuous measure.
Lowest pressure at the strict threshold (vNOTES-OVI = 2)
Lowest insufflation pressure at which the field is perfectly exposed (OVI = 2), blinded scoring.
Requirement for a third working instrument
Whether an instrument beyond the camera and the two standard working instruments - introduced through the platform's existing channel, not a new abdominal port - was required solely to expose the field or displace bowel (yes/no per case).
Postoperative nausea and vomiting - complete response
Proportion of participants with no nausea AND no vomiting AND no rescue antiemetic during the first 24 hours.
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Fatih Sultan Mehmet Training and Research Hospital
Lead sponsor
Acibadem University
Sponsor institution
Kutahya City Hospital
Collaborator
Kocaeli City Hospital
Collaborator
Dr. Lutfi Kirdar Kartal Training and Research Hospital
Collaborator
