Effect Of Trendelenburg Position And Pneumoperitoneum On Optic Nerve Sheath Diameter In Robot-Assisted Prostatectomy (ONSD-RALP)

March 18, 2026 updated by: Nursen Karaca, Ege University

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

This prospective study aims to evaluate the effect of steep Trendelenburg position and pneumoperitoneum on optic nerve sheath diameter in patients undergoing robot-assisted laparoscopic radical prostatectomy and open radical prostatectomy under general anesthesia. Increased intracranial pressure may occur during robotic surgery due to pneumoperitoneum and head-down positioning. Optic nerve sheath diameter measured by ocular ultrasonography is a non-invasive method used to assess intracranial pressure changes. Hemodynamic and respiratory parameters will also be recorded during surgery. The results of this study may help to better understand the physiological effects of surgical position and pneumoperitoneum during prostatectomy procedures.

Study Overview

Status

Recruiting

Conditions

Detailed Description

Robot-assisted laparoscopic radical prostatectomy requires steep Trendelenburg positioning and carbon dioxide pneumoperitoneum to improve the surgical field. These conditions may lead to increased intracranial pressure due to venous congestion and elevated intrathoracic pressure. Optic nerve sheath diameter measurement by ultrasonography is a noninvasive method that can be used to estimate changes in intracranial pressure during surgery.

In this prospective study, patients undergoing robot-assisted laparoscopic radical prostatectomy will be compared with patients undergoing open radical prostatectomy. Optic nerve sheath diameter will be measured at predefined time points during surgery using ocular ultrasonography. Hemodynamic parameters, respiratory variables, intra-abdominal pressure, duration of surgery, blood loss, and administered fluids will also be recorded.

The aim of this study is to evaluate the effect of pneumoperitoneum and steep Trendelenburg position on optic nerve sheath diameter and to determine the relationship between optic nerve sheath diameter and intraoperative physiological changes.

Study Type

Observational

Enrollment (Estimated)

50

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Turkey (Türkiye)
      • Izmir, Turkey (Türkiye), 35100
        • Recruiting
        • Ege University Faculty of Medicine Hospital
        • Contact:
        • Contact:
          • Işık Alper, Professor of Anesthesiology
          • Phone Number: 2140 +902323902140
          • Email: i.alper@yahoo.com

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult male patients aged 18 years and older with ASA physical status I-III who are scheduled for robot-assisted laparoscopic radical prostatectomy or open radical prostatectomy under general anesthesia at Ege University Faculty of Medicine Hospital will be included in this prospective observational study.

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Robot-Assisted Radical Prostatectomy
Patients undergoing robot-assisted laparoscopic radical prostatectomy under general anesthesia.
Open Radical Prostatectomy
Patients undergoing open radical prostatectomy under general anesthesia.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Optic Nerve Sheath Diameter
Time Frame: During surgery at predefined intraoperative time points
Measurement of optic nerve sheath diameter using ocular ultrasonography during surgery.
During surgery at predefined intraoperative time points

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ege University

Investigators

  • Principal Investigator: NURSEN KARACA, MD, Ege University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 5, 2026

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

September 1, 2026

Study Registration Dates

First Submitted

March 18, 2026

First Submitted That Met QC Criteria

March 18, 2026

First Posted (Actual)

March 24, 2026

Study Record Updates

Last Update Posted (Actual)

March 24, 2026

Last Update Submitted That Met QC Criteria

March 18, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 25-12.1T/18 (Other Identifier: Ege University Medical Research Ethics Committee)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared due to privacy and institutional restrictions.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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