Laparoscopic Gynecological SurgeryMOD-TRENDNCT07632287
Effects of Standard and Modified Z-Trendelenburg Positions on Cerebral Oxygenation and Optic Nerve Sheath Diameter
An observational study of Laparoscopic Gynecological Surgery, run by Ankara Etlik City Hospital at 1 site in Turkey (Türkiye).
Trial summary
The purpose of this study is to compare the effects of the standard Trendelenburg position and the modified Z-Trendelenburg position on cerebral oxygenation and optic nerve sheath diameter (ONSD) in patients undergoing laparoscopic surgery. Read more about this study
- Who is it for?
- Ages 18 to 80 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Laparoscopic Gynecological Surgery
- What is being tested?
- Standard Trendelenburg Position and Modified Z-Trendelenburg Position
- Type of treatment
- Surgery or procedure
- How many people
- 70 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 6 Mar 2026to 18 May 2026
- How long will I take part?
- 1 Day
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- Women only
- Healthy volunteers accepted
- Adult, Older adult
Study population: The study population consists of adult patients up to 80 years of age who [are admitted to the intensive care unit / are undergoing elective surgery / present to the emergency department]. The population excludes patients with known increased intracranial pressure, severe cerebrovascular, cardiovascular, or pulmonary diseases, morbid obesity (BMI > 35 kg/m^2), pregnancy, and any pre-existing ocular pathologies that could affect optic nerve sheath diameter (ONSD)
Who may be able to join
- Patients aged between 18 and 70 years
- American Society of Anesthesiologists (ASA) physical status I or II
- Scheduled for elective laparoscopic surgery requiring Trendelenburg position
- Provided written informed consent
Who cannot join
- Patient refusal to participate
- History of severe cerebrovascular disease
- Known increased intracranial pressure
- Pre-existing ocular pathology that could affect optic nerve sheath diameter (ONSD) measurements (e.g., glaucoma, optic neuritis, ocular trauma)
- Severe cardiovascular or pulmonary disease Body Mass Index (BMI) greater than 35 kg/m^2 Pregnancy
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Ankara Etlik City Hospital
Ankara, Ankara, 06010
About this study
Official title: Comparison of the Effects of Standard Trendelenburg and Modified Z Trendelenburg Positions on Cerebral Oxygenation (NIRS) and Optic Nerve Sheath Diameter in Laparoscopic Gynecological Cases
The purpose of this study is to compare the effects of the standard Trendelenburg position and the modified Z-Trendelenburg position on cerebral oxygenation and optic nerve sheath diameter (ONSD) in patients undergoing laparoscopic surgery. The prolonged use of the standard Trendelenburg position combined with pneumoperitoneum can increase intracranial pressure and affect cerebral blood flow. In this study, researchers will use non-invasive methods, including Near-Infrared Spectroscopy (NIRS) to monitor regional cerebral oxygenation, and ocular ultrasonography to measure ONSD as an indicator of intracranial pressure changes. The main goal is to determine whether the modified Z-Trendelenburg position serves as a safer physiological alternative by reducing these potential adverse effects compared to the standard position.
Read the detailed description
Laparoscopic surgeries frequently require patients to be placed in a steep Trendelenburg position with pneumoperitoneum to provide optimal surgical exposure. However, this combination induces significant physiological alterations, most notably an increase in intracranial pressure (ICP) and a potential compromise in cerebral venous drainage and regional cerebral oxygen saturation (rSO2). Non-invasive monitoring techniques, such as measuring the optic nerve sheath diameter (ONSD) via ultrasonography, provide reliable, real-time estimates of ICP changes. Additionally, Near-Infrared Spectroscopy (NIRS) allows for the continuous monitoring of cerebral oxygenation.
This prospective clinical study is designed to evaluate and compare the cerebral and hemodynamic impacts of the standard straight Trendelenburg position versus a modified Z-Trendelenburg position. Participants scheduled for elective laparoscopic procedures will be divided into specific positioning groups. Hemodynamic parameters, NIRS values, and ONSD measurements will be recorded at predefined time points throughout the surgery: at baseline, post-induction, after the establishment of pneumoperitoneum and positioning, at specific intervals during the surgery, and post-operatively in the recovery room. The primary hypothesis is that the modified Z-Trendelenburg position will attenuate the rise in ICP (reflected by a smaller increase in ONSD) and provide better cerebral oxygenation stability compared to the traditional standard position.
- Conditions
- Laparoscopic Gynecological Surgery
- Being tested
- Standard Trendelenburg Position, Modified Z-Trendelenburg Position
- Keywords
- Trendelenburg position, Optic Nerve Sheath Diameter, Near-Infrared Spectroscopy, Cerebral Oxygenation, Intracranial Pressure, Modified Z-Trendelenburg, Pneumoperitoneum, Laparoscopic surgery
- Medical subject headings
- Pneumoperitoneum
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Standard Trendelenburg PositionProcedure or surgery
Placement of the patient in the traditional straight head-down tilt position required for laparoscopic surgical access and pneumoperitoneum
Modified Z-Trendelenburg PositionProcedure or surgery
Placement of the patient in a modified head-down tilt position combined with leg flexion
| Study group | Role | What they receive |
|---|---|---|
| Standard Trendelenburg Cohort | Patients undergoing elective laparoscopic surgery placed in the standard straight Trendelenburg position. Receives: Procedure: Standard Trendelenburg Position | |
| Modified Z-Trendelenburg Cohort | Patients undergoing elective laparoscopic surgery placed in the modified Z-Trendelenburg position (head-down tilt combined with leg flexion). Receives: Procedure: Modified Z-Trendelenburg Position |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Regional Cerebral Oxygen Saturation (rSO2)
Regional cerebral oxygen saturation (rSO2) will be measured bilaterally using Near-Infrared Spectroscopy (NIRS) sensors placed on the patient's forehead. This non-invasive monitoring will be used to evaluate cerebral oxygenation changes during different surgical positions and pneumoperitoneum. Values will be recorded as percentages (%).
Measured: Baseline (before anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Secondary outcomes (4)
Change in Mean Arterial Pressure (MAP)
Mean Arterial Pressure (MAP) will be continuously monitored and recorded to evaluate the cardiovascular effects of the pneumoperitoneum and modified positioning. Values will be reported in mmHg.
Measured: Baseline ( 10 minutes after anesthesia induction), at 10,45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Change in Optic Nerve Sheath Diameter (ONSD)
Intracranial pressure changes will be evaluated indirectly by measuring the optic nerve sheath diameter (ONSD) using ocular ultrasonography. Measurements will be taken bilaterally and recorded in millimeters (mm).
Measured: Baseline ( 10 minutes after anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Change in Peak Airway Pressure (Ppeak)
Peak airway pressure will be monitored continuously and recorded to evaluate the effects of pneumoperitoneum and different surgical positions on respiratory mechanics. Values will be reported in centimeters of water (cmH2O).
Measured: Baseline (10 minutes after anesthesia induction), at 10,45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine posi
Change in End-tidal Carbon Dioxide (EtCO2)
End-tidal carbon dioxide levels will be monitored continuously via capnography to evaluate ventilation status during pneumoperitoneum and different positioning. Values will be reported in millimeters of mercury (mmHg).
Measured: Baseline (10 minutes after anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine positi
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Jun 2026
- Study start6 Mar 2026
- Primary completion18 May 2026
- Study completion18 May 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Laparoscopic Gynecological SurgeryStudies of the same condition, open and under way.
- More trials run by Ankara Etlik City HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 70 participants (actual)
- Target duration
- 1 Day
Sponsor and investigators
- Lead sponsor
- Ankara Etlik City Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Neriman Doğan, Ankara Etlik City Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07632287
- Sponsor's protocol ID
- AEŞH-EK-2026-048
- Acronym
- MOD-TREND
- Status last verified
- Jun 2026
- First submitted
- 18 May 2026
- Last updated
- 8 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The study population consists of adult female patients, aged 18 to 80 years, classified with an American Society of Anesthesiologists (ASA) physical status of I or II, who are scheduled to undergo elective laparoscopic gynecological surgery under general anesthesia at Ankara Etlik City Hospital. Eligible participants must have a Body Mass Index (BMI) between 18 and 30 kg/m2 and require the Trendelenburg position during surgery. Patients are excluded from the study population if they have a history of intracranial pathology, neurological disorders, severe ophthalmologic conditions (such as glaucoma), cerebrovascular diseases, severe cardiac or pulmonary diseases, profound anemia (Hb \< 10 g/dL), or if they are pregnant.
Study at a glance
From the registry record, last updated by the sponsor on 8 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of the Effects of Standard Trendelenburg and Modified Z Trendelenburg Positions on Cerebral Oxygenation (NIRS) and Optic Nerve Sheath Diameter in Laparoscopic Gynecological Cases
- ClinicalTrials.gov ID
- NCT07632287
- Acronym / sponsor ID
- MOD-TREND / AEŞH-EK-2026-048
- Conditions
- Laparoscopic Gynecological Surgery
- Keywords
- Trendelenburg position, Optic Nerve Sheath Diameter, Near-Infrared Spectroscopy, Cerebral Oxygenation, Intracranial Pressure, Modified Z-Trendelenburg, Pneumoperitoneum, Laparoscopic surgery
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 70 participants (actual)
- Lead sponsor
- Ankara Etlik City HospitalOther government
- Study start
- 6 Mar 2026 (actual)
- Primary completion
- 18 May 2026 (actual)
- Study completion
- 18 May 2026 (actual)
- First posted
- 8 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to compare the effects of the standard Trendelenburg position and the modified Z-Trendelenburg position on cerebral oxygenation and optic nerve sheath diameter (ONSD) in patients undergoing laparoscopic surgery. The prolonged use of the standard Trendelenburg position combined with pneumoperitoneum can increase intracranial pressure and affect cerebral blood flow. In this study, researchers will use non-invasive methods, including Near-Infrared Spectroscopy (NIRS) to monitor regional cerebral oxygenation, and ocular ultrasonography to measure ONSD as an indicator of intracranial pressure changes. The main goal is to determine whether the modified Z-Trendelenburg position serves as a safer physiological alternative by reducing these potential adverse effects compared to the standard position.
Detailed description
Laparoscopic surgeries frequently require patients to be placed in a steep Trendelenburg position with pneumoperitoneum to provide optimal surgical exposure. However, this combination induces significant physiological alterations, most notably an increase in intracranial pressure (ICP) and a potential compromise in cerebral venous drainage and regional cerebral oxygen saturation (rSO2). Non-invasive monitoring techniques, such as measuring the optic nerve sheath diameter (ONSD) via ultrasonography, provide reliable, real-time estimates of ICP changes. Additionally, Near-Infrared Spectroscopy (NIRS) allows for the continuous monitoring of cerebral oxygenation.
This prospective clinical study is designed to evaluate and compare the cerebral and hemodynamic impacts of the standard straight Trendelenburg position versus a modified Z-Trendelenburg position. Participants scheduled for elective laparoscopic procedures will be divided into specific positioning groups. Hemodynamic parameters, NIRS values, and ONSD measurements will be recorded at predefined time points throughout the surgery: at baseline, post-induction, after the establishment of pneumoperitoneum and positioning, at specific intervals during the surgery, and post-operatively in the recovery room. The primary hypothesis is that the modified Z-Trendelenburg position will attenuate the rise in ICP (reflected by a smaller increase in ONSD) and provide better cerebral oxygenation stability compared to the traditional standard position.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 1 Day
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Standard Trendelenburg Cohort | – | Procedure: Standard Trendelenburg PositionPatients undergoing elective laparoscopic surgery placed in the standard straight Trendelenburg position. |
| Modified Z-Trendelenburg Cohort | – | Procedure: Modified Z-Trendelenburg PositionPatients undergoing elective laparoscopic surgery placed in the modified Z-Trendelenburg position (head-down tilt combined with leg flexion). |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consists of adult patients up to 80 years of age who [are admitted to the intensive care unit / are undergoing elective surgery / present to the emergency department]. The population excludes patients with known increased intracranial pressure, severe cerebrovascular, cardiovascular, or pulmonary diseases, morbid obesity (BMI > 35 kg/m^2), pregnancy, and any pre-existing ocular pathologies that could affect optic nerve sheath diameter (ONSD)
Key inclusion criteria (4 listed)
- Patients aged between 18 and 70 years
- American Society of Anesthesiologists (ASA) physical status I or II
- Scheduled for elective laparoscopic surgery requiring Trendelenburg position
- Provided written informed consent
Key exclusion criteria (5 listed)
- Patient refusal to participate
- History of severe cerebrovascular disease
- Known increased intracranial pressure
- Pre-existing ocular pathology that could affect optic nerve sheath diameter (ONSD) measurements (e.g., glaucoma, optic neuritis, ocular trauma)
- Severe cardiovascular or pulmonary disease Body Mass Index (BMI) greater than 35 kg/m^2 Pregnancy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Standard Trendelenburg PositionPlacement of the patient in the traditional straight head-down tilt position required for laparoscopic surgical access and pneumoperitoneum | Procedure or surgery | Standard Trendelenburg Cohort |
| Modified Z-Trendelenburg PositionPlacement of the patient in a modified head-down tilt position combined with leg flexion | Procedure or surgery | Modified Z-Trendelenburg Cohort |
Primary outcome
Change in Regional Cerebral Oxygen Saturation (rSO2)
Time frame: Baseline (before anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Regional cerebral oxygen saturation (rSO2) will be measured bilaterally using Near-Infrared Spectroscopy (NIRS) sensors placed on the patient's forehead. This non-invasive monitoring will be used to evaluate cerebral oxygenation changes during different surgical positions and pneumoperitoneum. Values will be recorded as percentages (%).
4 secondary outcomes
Change in Mean Arterial Pressure (MAP)
Time frame: Baseline ( 10 minutes after anesthesia induction), at 10,45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Change in Optic Nerve Sheath Diameter (ONSD)
Time frame: Baseline ( 10 minutes after anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.
Change in Peak Airway Pressure (Ppeak)
Time frame: Baseline (10 minutes after anesthesia induction), at 10,45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine posi
Change in End-tidal Carbon Dioxide (EtCO2)
Time frame: Baseline (10 minutes after anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine positi
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Jun 2026.
- Individual participant dataSharing planned: No. The study population consists of adult female patients, aged 18 to 80 years, classified with an American Society of Anesthesiologists (ASA) physical status of I or II, who are scheduled to undergo elective laparoscopic gynecological surgery under general anesthesia at Ankara Etlik City Hospital. Eligible participants must have a Body Mass Index (BMI) between 18 and 30 kg/m2 and require the Trendelenburg position during surgery. Patients are excluded from the study population if they have a history of intracranial pathology, neurological disorders, severe ophthalmologic conditions (such as glaucoma), cerebrovascular diseases, severe cardiac or pulmonary diseases, profound anemia (Hb < 10 g/dL), or if they are pregnant.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Laparoscopic Gynecological Surgery, run by Ankara Etlik City Hospital at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 8 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Regional Cerebral Oxygen Saturation (rSO2) (time frame: Baseline (before anesthesia induction), at 10, 45, 60, and 90 minutes after establishing pneumoperitoneum and surgical positioning, and 10 minutes after returning to the supine position.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Jun 2026.