Effect of Carbon Dioxide Pressure on Optic Nerve Sheath Diameter in Laparoscopic Transperitoneal Nephrectomy

NCT07262125 | Enrolling By Invitation

• 1 other identifier: Optic Nerve Sheat Laparoscopy
• Study Type: interventional
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

Nephrectomy is a surgical procedure performed for various indications, and with the development and increasing availability of advanced diagnostic techniques, its incidence has been rising. Today, in appropriate cases, laparoscopic surgery is recommended due to its minimally invasive nature and its surgical success rates being comparable to those of open surgery. In laparoscopic surgery, to achieve optimal visualization, a 45° lateral decubitus position is applied, followed by the creation of a pneumoperitoneum using carbon dioxide gas. While the cardiopulmonary effects of this procedure have been shown to be minimal, studies on its intracranial effects are limited. Cerebral perfusion pressure is defined as the difference between mean arterial pressure and either central venous pressure or intracranial pressure, whichever is higher. Intracranial pressure can be assessed non-invasively using ultrasonographic measurement of the Optic Nerve Sheath Diameter (ONSD). The retrobulbar segment of the optic nerve is surrounded by a distensible subarachnoid space, which expands in response to increased intracranial pressure. The effect of increased intra-abdominal pressure during laparoscopic surgery on intracranial pressure, and its impact on ONSD, will be evaluated non-invasively. In patients scheduled for laparoscopic kidney surgery, the Optic Nerve Sheath Diameter will be measured transorbitally using ultrasonography by the investigator at various stages of the surgery (before anesthesia, after anesthesia, in the lateral decubitus position, during pneumoperitoneum, and at routine intraoperative pressure levels). Additionally, standard monitoring parameters such as pulse rate, blood pressure, oxygen saturation, and End-Tidal CO₂ will be recorded. The Optic Nerve Sheath Diameter, which serves as an indicator of increased intracranial pressure, will be compared with variables such as surgical positioning, BMI, ASA score, and other relevant factors.

Conditions

Optic Nerve Sheath Diameter; Laparoscopic Nephrectomy

Keywords

optic nerve sheath diameter; laparoscopic nephrectomy

Outcome Measures

Primary Outcomes (1)

• Change in optic nerve sheath diameter (ONSD) with increasing intraabdominal CO₂ pressure

  Change in optic nerve sheath diameter (ONSD) with increasing intraabdominal CO₂ pressure

  Preop Supine before intubation → During surgery (baseline supine → lateral decubitus positioning → pneumoperitoneum → each pressure level: 14, 16, 18, 20 mmHg → Postop Supine 5 minutes after extubation of the patient

Study Arms (1)

Routine Laparoscopic Pneumoperitoneum

OTHER

Routine Laparoscopic Pneumoperitoneum of the patients

Diagnostic Test: Optic Nerve Sheath Diameter Measurement

Interventions

Optic Nerve Sheath Diameter Measurement DIAGNOSTIC_TEST

Optic Nerve Sheath Diameter Measurement, Oxygen saturation and End Tidal CO2 measurements when Pre-operational Supine position, after intubation, Lateral decubitus position, after Pneumoperitoneum, CO2 pressure level at 14-16-18-20 and Post-operational supine position

Routine Laparoscopic Pneumoperitoneum

Eligibility Criteria

• Age: 31 Years - 69 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male and female patients aged 31-69 years.
• Diagnosis of renal cancer (ICD Code C64).
• Planned laparoscopic radical or partial nephrectomy based on current guidelines and patient consent in the Urology Council.

You may not qualify if:

• Presence of any condition that prevents transorbital measurement of the optic nerve sheath (e.g., orbital trauma, severe periorbital edema, or ocular abnormalities affecting optic nerve imaging)
• Presence of a medical condition that precludes positioning the patient in a 45-degree lateral decubitus position (e.g., severe scoliosis, respiratory compromise, or spinal instability)
• Known or suspected intracranial pathology that may independently elevate intracranial pressure (e.g., intracranial tumors, hydrocephalus, recent traumatic brain injury)

Sponsors & Collaborators

• Fatih Sultan Mehmet Training and Research Hospital: lead

Study Sites (1)

Fatih Sultan Mehmet Research and Training Hospital

Istanbul, Ataşehir, 34100, Turkey (Türkiye)

Location

Related Publications (2)

• Atasever AG, Salviz EA, Senturk Ciftci H, Bingul ES, Sivrikoz N, Erdem S, Savran Karadeniz M. The Effects of Lateral 45 degrees Head-Down Position and Carbon Dioxide Pneumoperitoneum on the Optic Nerve Sheath Diameter in Patients Undergoing Laparoscopic Transperitoneal Nephrectomies: A Prospective Observational Study. J Laparoendosc Adv Surg Tech A. 2023 Feb;33(2):171-176. doi: 10.1089/lap.2022.0344. Epub 2022 Aug 25.

  PMID: 36036829 BACKGROUND

• Chin JH, Seo H, Lee EH, Lee J, Hong JH, Hwang JH, Kim YK. Sonographic optic nerve sheath diameter as a surrogate measure for intracranial pressure in anesthetized patients in the Trendelenburg position. BMC Anesthesiol. 2015 Mar 31;15:43. doi: 10.1186/s12871-015-0025-9. eCollection 2015.

  PMID: 25861241 BACKGROUND

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: MD, Urologist

Study Record Dates

• First Submitted: September 21, 2025
• First Posted: December 3, 2025
• Study Start: December 1, 2024
• Primary Completion: December 1, 2025
• Study Completion: January 1, 2026
• Last Updated: December 3, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)