Semi-sitting Versus Supine Position in Endoscopic Skull Base Surgery (PosESS)

April 28, 2025 updated by: University Hospital, Basel, Switzerland

Semi-sitting Versus Supine Position in Endoscopic Skull Base Surgery (PosESS-Study) - Study Protocol for a Randomized-controlled Single-blinded Superiority Trial

This study is to prospectively compare the standard supine (control group) and the semi-sitting position (head elevation of 30°; intervention group) in endoscopic endonasal pituitary surgery.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The endonasal endoscopic approach (EEA) for pituitary surgery is standardly performed with the patient in supine position (SP). The semi-sitting position (SSP) is routinely used for the traditional microscopic transsphenoidal approach and also for posterior fossa surgery. The SSP results in lower intracranial pressure when compared to the supine position due to decreased venous congestion. As a result, intraoperative bleeding may be reduced, potentially leading to decreased surgical morbidity and improved surgical workflow. Studies during endoscopic sinus surgery have shown a significant reduction of blood loss when the patient is placed in a reverse Trendelenburg position with a head elevation of 30°. This study is to prospectively compare the standard supine (control group) and the semi-sitting position (head elevation of 30°; intervention group) in endoscopic endonasal pituitary surgery.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
54

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Switzerland
      • Basel, Switzerland, 4031
        • Department of Neurosurgery, University Hospital Basel

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients with a presumed pituitary pathologies who are suitable for endoscopic endonasal surgical resection

Exclusion Criteria:

  • Patients with known hemorrhagic or thrombophilic disorders
  • Patients with conditions associated with high central venous pressure: congestive heart failure, pulmonary hypertension, chronic obstructive pulmonary disease (COPD), interstitial lung disease, pregnancy
  • Patients with poor cardiopulmonary condition (unable to perform 4 metabolic equivalents without stopping (climb a flight of stairs))

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Study Intervention
Endonasal endoscopic pituitary surgery in semi-sitting position
Procedure: Endonasal endoscopic pituitary surgery in semi-sitting position
Patients will be placed in semi-sitting position. To achieve the semi-sitting position, the patient is placed in supine position. The operating table is then separated and flexed to elevate the torso (angle of 30°). The head, which is fixed in a head clamp, is slightly flexed to bring the floor of the sella right in front of the surgeon and gently rotated toward the operating team.
Active Comparator: Control Intervention
Endonasal endoscopic pituitary surgery in supine position
Procedure: Endonasal endoscopic pituitary surgery in supine position
Patients will be operated in the standard supine neutral position

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Intraoperative blood loss
Time Frame: Intraoperative
Intraoperative blood loss, calculated as follow: volume in the suction bag minus volume of rinsing water in Milliliters (ml). The surgery is divided into four steps: 1. endonasal phase, 2. osteodural exposure. 3. sellar stage and 4. skull base defect closure. For each step, the primary outcome will be assessed.
Intraoperative
Frequency of interruption of the surgical workflow due to disturbing blood or a bleeding in the surgical field (number)
Time Frame: During surgery
Frequency of interruption of the surgical workflow due to disturbing blood or a bleeding in the surgical field. This will be assessed by an independent blinded neurosurgeon, who will watch the operative video after the surgery.
During surgery

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in intraoperative Mean Arterial Pressure (MAP)
Time Frame: Intraoperative
MAP will be monitored during the whole surgery using the software Copra ©, which allows a continuous data extraction
Intraoperative
Amount of intravenous fluid administered during surgery (ml)
Time Frame: Intraoperative
Amount of intravenous fluid administered during surgery (ml)
Intraoperative
Need for vasoactive drugs (vasopressors) (number)
Time Frame: at Day 1 (day of surgery)
Need for vasoactive drugs (vasopressors) (number)
at Day 1 (day of surgery)
Incidence of air embolism (number)
Time Frame: at Day 1 (day of surgery)
Incidence of air embolism (number)
at Day 1 (day of surgery)
Operative time (minutes)
Time Frame: During surgery
Operative time (minutes)
During surgery
Degree of descent or prolapse of the diaphragma sellae into the sellar cavity
Time Frame: Intraoperative
Intraoperative assessment of the degree of descent or prolapse of the diaphragma sellae into the sellar cavity (class I to V, according to the classification of Abdelmaksoud et al)
Intraoperative
Occurrence of a cerebrospinal fluid (CSF) leak during surgery (assessed by the operating neurosurgeon) (yes/ no)
Time Frame: During surgery
Occurrence of a cerebrospinal fluid (CSF) leak during surgery (assessed by the operating neurosurgeon)
During surgery
Surgical ergonomics
Time Frame: at Day 1 (day of surgery)
Surgical ergonomics assessed by the means of a standardized questionnaire. The surgeon will be asked to rate the intensity of neck and arm discomfort and the frequency of surgical flow interruption due to a suboptimal trajectory of the endoscope and the instruments due to the patient Position (1 = no discomfort, 2 = medium discomfort, 3 = high discomfort).
at Day 1 (day of surgery)
Incidence of rhinoliquorrhoea (number)
Time Frame: at 3 months after surgery
Incidence of rhinoliquorrhoea (number)
at 3 months after surgery

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Hospital, Basel, Switzerland

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Jonathan Rychen, Department of Neurosurgery, University Hospital Basel

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 22, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 29, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 29, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 5, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 6, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 14, 2020

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 29, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 28, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2020-02115; ch20Rychen

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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