CompletedNot Applicable

Impact of Reverse Trendelenburg on ONSD in Obesity Surgery

Turkey (Türkiye)90 participantsStarted 2026-01-01

Plain-language summary

This prospective randomized controlled trial aims to investigate the effect of reverse Trendelenburg positioning applied before pneumoperitoneum on optic nerve sheath diameter (ONSD) and, consequently, intracranial pressure during laparoscopic bariatric surgery. Patients will be randomly assigned to two groups, and perioperative changes in ONSD will be compared between the groups. The primary hypothesis of the study is that applying the reverse Trendelenburg position before pneumoperitoneum may attenuate ONSD enlargement and thereby help prevent increases in intracranial pressure.

Who can participate

Age range

18 Years – 65 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Age between 18 and 65 years. * American Society of Anesthesiologists (ASA) physical status I-III. * Body mass index (BMI) ≥ 35 kg/m² and scheduled for elective laparoscopic bariatric surgery. * Ability to provide written informed consent. * Willingness to participate in the study and comply with study procedures. Exclusion Criteria: * Age younger than 18 years or older than 65 years. * Refusal or inability to provide written informed consent. * History of ophthalmologic disease that may affect optic nerve sheath diameter (ONSD) measurements (e.g., glaucoma, optic neuritis, optic nerve tumors, severe ocular trauma, previous ocular surgery). * Known intracranial pathology, including intracranial hypertension, hydrocephalus, intracranial mass lesions, or cerebrovascular disease. * Neurological disorders that may influence intracranial pressure measurements. * Emergency surgery. * Pregnancy. * Severe cardiopulmonary disease (e.g., decompensated heart failure, severe pulmonary hypertension, severe chronic obstructive pulmonary disease). * Inability to obtain adequate ocular ultrasonography images for ONSD measurement. * Conversion from laparoscopic to open surgery. Intraoperative events requiring deviation from the study protocol.

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Change in Optic Nerve Sheath Diameter (ONSD)

Timeframe: Baseline (before induction of anesthesia), immediately after induction, 5 minutes after pneumoperitoneum and positioning, and at the end of surgery.

Trial details

NCT IDNCT07639502

SponsorBagcilar Training and Research Hospital

Sponsor typeOTHER_GOV

Study typeINTERVENTIONAL

Primary completion2026-04-15

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