DOI: 10.1177/2168023x261492488 ISSN: 2168-023X

Effect of Reverse Trendelenburg Positioning Before Pneumoperitoneum on Optic Nerve Sheath Diameter in Patients with Class III Obesity Undergoing Laparoscopic Sleeve Gastrectomy: A Randomized Controlled Trial

Sezen Kumaş Solak, Rasim Onur Karaoğlu, Lokman Şahin, Mehmet Bay, Serdar Demirgan
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Background:

CO 2 pneumoperitoneum during laparoscopic sleeve gastrectomy may raise intraabdominal and intrathoracic pressures, impair cerebral venous drainage, and increase optic nerve sheath diameter (ONSD), a noninvasive surrogate for intracranial pressure. This study assessed whether reverse Trendelenburg positioning before pneumoperitoneum attenuates this increase in class III obesity.

Methods:

In this prospective randomized controlled trial, 83 patients with class III obesity received pneumoperitoneum either supine (Group-S, n = 41) or in reverse Trendelenburg (Group-RT, n = 42). Bilateral ONSD, hemodynamics, peak airway pressure, and end-tidal CO 2 were recorded at six time points from induction to desufflation.

Results:

Baseline characteristics and ONSD values were comparable between groups. A linear mixed-effects model showed a significant group by time interaction for both eyes ( p < 0.001). ONSD was higher in Group-S than Group-RT after insufflation (+0.84 mm) and after positioning (+0.31 mm), with differences diminishing further to ≤0.12 mm at later time points. More Group-S patients reached ONSD ≥5.8 mm. The difference-in-differences was +0.58 mm (95% confidence interval 0.47–0.68; p < 0.001), reflecting a blunted initial rise in Group-RT. Hemodynamics did not differ significantly.

Conclusions:

Reverse Trendelenburg positioning attenuated ONSD rise in class III obesity. As ICP was not measured directly, findings should be interpreted at the surrogate level.

Clinical Trial Registration:

This trial was registered at ClinicalTrials.gov ( https://clinicaltrials.gov/ ), registration number NCT07639502.

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