ANATOMICAL VARIATIONS OF THE SPHENOID SINUS ASSESSED WITHMDCT

BackgroundThe aim of this study was to assess the incidence of the anatomical variations of the sphenoidsinus in 293 patients studied by multidetector computed tomography (MDCT).Materials and MethodsThe MDCT (64 rows) studies of the paranasal sinuses of 293 patients, performed in 2006-2009,were reviewed to assess anatomical variations of the sphenoid sinus and related neurovascularstructures. Anatomical variations were evaluated on 1 mm thick MPR reformations, displayed on ahigh resolution workstation screen. Pneumatization of the anterior clinoid process (ACP), pterygoidrecess (PR), protrusion of the internal carotid artery (ICA), optic nerve (ON), maxillary and vidiannerve into the sphenoid sinus, as well as insertion of sphenoid sinus septa on neurovascular canalswere assessed. Onodi cells were also recorded.ResultsMDCT findings were: pneumatization of the ACP with ON protrusion in 78 patients (26.6%); Onodicells in 107 patients (36.5%); PR in 83 patients (28%); protrusion of ICA in 107 patients (36%);protrusion of maxillary nerve in 120 patients (40%); protrusion of vidian nerve in 120 patients(40%); sphenoid sinus septa in 34 patients (11.6%); insertion of sphenoid sinus septa onneurovascular canals in 33 patients (11.25%), of whom on optic canal in 2 patients, on carotidcanal in 30 patients, on vidian canal in 1 patient; in 1 patient (0.3%) maxillary and vidian nervesprotruded in a right Onodi cell that formed a pterygoid recess.ConclusionsPreoperative recognition of the anatomical variations by computed tomography is mandatorybefore FESS, to prevent surgical complications.