Sphenoid sinus pneumatization types, extensions and adjacent neurovascular structures: a systematic review with meta-analysis and meta-regression

The sphenoid sinus (SS) exhibits significant anatomical variability that critically impacts the safety and efficacy of endoscopic transsphenoidal surgery. This systematic review and meta-analysis aims to establish global prevalence rates for SS pneumatization patterns, extensions, and the relationship with adjacent neurovascular structures to guide surgical planning. A systematic literature search was conducted across PubMed, Google Scholar, Scopus, and Web of Science until October 2025. Studies reporting SS pneumatization types, extensions, and neurovascular protrusions/dehiscences based on imaging or cadaveric dissection were included. Random-effect models were used for the meta-analysis. The sellar type was the predominant pneumatization pattern, with the complete sellar type accounting for 48.39%. Statistically significant results were identified based on nationality and study type. Extensions into the greater wing (34.17%) and pterygoid process (25.51%) were common. The Vidian nerve (VN) showed the highest rates of protrusion (32.61%) and dehiscence (14.60%), followed by the internal carotid artery (ICA) (protrusion: 29.77%; dehiscence: 9.47%) and optic nerve (ON) (protrusion: 23.46%; dehiscence: 10.92%). The imaging modality used did not affect the neurovascular structure variations. The SS is a highly variable structure with frequent extensions that expose vital neurovascular structures to surgical risk. Although the subgroup analyses did not depict statistically significant results, computed tomography scan with less than 1 mm slice thickness should be used for evaluation of SS anatomy. The high prevalence of VN and ICA dehiscence necessitates rigorous preoperative evaluation. These findings provide a crucial anatomical reference for optimizing surgical approaches and minimizing complications in skull base surgery.