Head-down position and abdominal gas effects on optic nerve sheath size during robotic prostate removal

Effect of Steep Trendelenburg Position and Pneumoperitoneum on Optic Nerve Sheath Diameter in Robot-Assisted Laparoscopic Radical Prostatectomy: A Prospective Study

Observational Ege University · NCT07491198

This will see if the steep head-down position and abdominal gas used during robot-assisted prostate removal increase the optic nerve sheath diameter in men having prostatectomy.

Quick facts

Study typeObservational
Enrollment50 (estimated)
Ages18 Years and up
SexMale
SponsorEge University Academic / other
Locations1 site (Izmir)
Trial IDNCT07491198 on ClinicalTrials.gov

What this trial studies

This prospective observational study will measure optic nerve sheath diameter by ocular ultrasound at predefined time points before, during, and after surgery in patients undergoing robot-assisted laparoscopic radical prostatectomy and in a comparison group undergoing open radical prostatectomy. Intraoperative hemodynamic and respiratory variables, intra-abdominal pressure, blood loss, fluid administration, and surgery duration will be recorded to correlate physiological changes with optic nerve sheath measurements. The aim is to determine whether pneumoperitoneum and steep Trendelenburg positioning produce measurable increases in optic nerve sheath diameter and whether those changes relate to other intraoperative parameters. Data will be collected at a single center and analyzed to compare the two surgical approaches.

Who should consider this trial

Good fit: Adult men (≥18 years) scheduled for robot-assisted or open radical prostatectomy under general anesthesia with ASA physical status I–III, no prior intracranial or significant ocular disease, and able to give informed consent.

Not a fit: Patients with prior intracranial surgery, known ocular disease, very high intraocular pressure, or those not undergoing prostatectomy are unlikely to benefit directly from this study's findings.

Why it matters

Potential benefit: If successful, the findings could help guide anesthetic and positioning practices to reduce intracranial pressure–related risks during prostatectomy.

How similar studies have performed: Previous small studies have reported increases in optic nerve sheath diameter with steep Trendelenburg and pneumoperitoneum, but results are variable and larger comparative data are limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age ≥ 18 years
* ASA physical status I-III
* Patients scheduled for robot-assisted laparoscopic radical prostatectomy or open radical prostatectomy under general anesthesia
* Written informed consent obtained

Exclusion Criteria:

* History of intracranial surgery or intracranial lesion
* Known ocular disease (glaucoma, retinal detachment, diabetic retinopathy, previous ocular surgery, etc.)
* Intraocular pressure greater than 30 mmHg
* Refusal to participate in the study

Where this trial is running

Izmir

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Prostate CancerOptic Nerve Sheath DiameterRobot-Assisted Radical ProstatectomySteep Trendelenburg Position With Penumoperitoneum in Robot Assisted Laparoscopic ProstatectomyTrendelenburg PositionPneumoperitoneum
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.