RESUMO
Background: Sphenoid sinus is the most inaccessible paranasal sinus; enclosed within the sphenoid bone and intimately related to numerous vital neural and vascular structures. Anatomic variation of the sphenoid sinus is well documented and may complicate surgery in such a place. Objective: To outline the surgically risky anatomic variants of the sphenoid sinus as well as the variable relationships between the sinus and related neurovascular structures; for the safe removal of intrasphenoid and pituitary lesions. Materials and Methods: We undertook a prospective review of 300 paranasal sinus CT scans of Libyan patients; coronal CT scans were obtained by special parameter techniques. We assessed pneumatization of pterygoid process (PP); anterior clinoid process (ACP); and greater wing of sphenoid (GWS); we also examined protrusion and dehiscence of internal carotid artery (ICA); optic nerve (ON); maxillary nerve (MN); and vidian nerve (VN) into the sphenoid sinus cavity. Results: Pneumatization of PP; ACP; and GWS were seen in 87 (29); 46 (15.3); and 60 patients (20); respectively. Protrusion of ICA; ON; MN; and VN were noticed in 123 (41); 107 (35.6); 73 (24.3); and 81 patients (27); respectively; dehiscence of these structures was encountered in 90 (30); 92 (30.6); 39 (13); and 111 patients (37); respectively. Statistically; there was a highly significant association between ACP pneumatization and ICA protrusion; ACP pneumatization and ON protrusion; PP pneumatization and VN protrusion; and GWS pneumatization and MN protrusion (p-value 0.001). Conclusion: The sphenoid sinus is highly variable; this variability necessitates a comprehensive understanding of the regional sphenoid sinus anatomy by a detailed CT scan sinus examination before surgery in and around the sinus. This study indicates the possibility of a racial anatomical variation of the sphenoid sinus in the Libyan population