Variations of sphenoid pneumatization: a CBCT study

BACKGROUND. The pneumatization pattern of the sphenoid sinus seems rather unpredictable, as resulted from previous studies. It is however extremely important for endoscopic approaches to target structures of the middle cranial fossa, such as the pituitary gland.

MATERIAL AND METHODS. We aimed at documenting by Cone Beam Computed Tomography (CBCT) the possibilities of anatomic variation of the sphenoid sinus. 25 randomly selected patients were retrospectively analyzed.

RESULTS. In 56%, the left and right sphenoidal sinuses were bilaterally symmetrical with respect to the sagittal pneumatization type: four patients had sellar types, one had presellar type and in nine cases the sphenoidal sinuses were reaching posteriorly to the sella turcica. Only in 8% of cases were found conchal types of pneumatization, but they were part of anatomical pictures including Onodi air cells. Such an Onodi cell presented a posterior (sphenoidal) recess reaching posteriorly and superiorly to the pterygopalatine fossa. The recesses of the sphenoid sinus were also documented: anterior or septal, ethmoidal, maxillary, clinoidal and lateral. In 32% was found a lateral recess only engaged between the vidian and maxillary nerve canals.

CONCLUSION. It appears that CBCT is a reliable tool for accurate anatomic identification of the sphenoid sinus pneumatization pattern, on a case-by-case basis.