METHODS: The current review followed PRISMA 2020 guidelines. A systematic advanced electronic search was performed in four databases Medline (via PubMed), Scopus, Web of Science (WoS) and Lilacs in December 2023. Studies that assessed the anatomical variations of the SS that affect the outcomes of ETSS were eligible for inclusion. A qualitative synthesis of the methodology and results of the included studies was carried out. Quality assessment was performed using the National Institute of Health (NIH) quality assessment tool (last accessed on December 24, 2023).

RESULTS: A total of 14 studies were included in the qualitative synthesis. Most of the studies included in the review found that the sellar pneumatization was the commonest followed by the postsellar type. Single intersphenoid sinus septum (ISS) was found to be the most common variation, which is more frequently found in males compared to females. There was sex difference seen in the attachment of the ISS to the carotid canal. It is more commonly attached to the posterolateral wall of the sinus in males compared to the females. Though complicated cases were less compared to uncomplicated ones, cerebrospinal fluid (CSF) leak was the leading post operative complication amongst the complicated cases and paranasal sinus (PNS) computed tomography (CT) scan showed ISS findings differed from intraoperative findings.