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Semi-sitting Versus Supine Position in Endoscopic Skull Base Surgery

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

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04584866
Acronym
PosESS
Enrollment
54
Registered
2020-10-14
Start date
2021-01-22
Completion date
2024-06-29
Last updated
2025-04-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Pituitary Adenoma

Keywords

endoscopic endonasal pituitary surgery, endoscopic skull base surgery, intracranial venous pressure, venous air embolism

Brief summary

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.

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.

Interventions

PROCEDUREEndonasal 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.

PROCEDUREEndonasal endoscopic pituitary surgery in supine position

Patients will be operated in the standard supine neutral position

Sponsors

University Hospital, Basel, Switzerland
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)

Intervention model description

prospective randomized single-blinded controlled superiority trial

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

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))

Design outcomes

Primary

MeasureTime frameDescription
Intraoperative blood lossIntraoperativeIntraoperative 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.
Frequency of interruption of the surgical workflow due to disturbing blood or a bleeding in the surgical field (number)During surgeryFrequency 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.

Secondary

MeasureTime frameDescription
Need for vasoactive drugs (vasopressors) (number)at Day 1 (day of surgery)Need for vasoactive drugs (vasopressors) (number)
Incidence of air embolism (number)at Day 1 (day of surgery)Incidence of air embolism (number)
Operative time (minutes)During surgeryOperative time (minutes)
Change in intraoperative Mean Arterial Pressure (MAP)IntraoperativeMAP will be monitored during the whole surgery using the software Copra ©, which allows a continuous data extraction
Occurrence of a cerebrospinal fluid (CSF) leak during surgery (assessed by the operating neurosurgeon) (yes/ no)During surgeryOccurrence of a cerebrospinal fluid (CSF) leak during surgery (assessed by the operating neurosurgeon)
Surgical ergonomicsat 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).
Incidence of rhinoliquorrhoea (number)at 3 months after surgeryIncidence of rhinoliquorrhoea (number)
Degree of descent or prolapse of the diaphragma sellae into the sellar cavityIntraoperativeIntraoperative 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)
Amount of intravenous fluid administered during surgery (ml)IntraoperativeAmount of intravenous fluid administered during surgery (ml)

Countries

Switzerland

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026