[Anatomic variations of the septation within the sphenoid sinus on CT scan images--an initial report]

The aim of this study was to assess the septation of the sphenoid sinuses and relationship between the number and position of septa in the adult Polish subpopulation.

A retrospective study of the CT examination of the paranasal sinuses 207 patients (101 male, 106 female) were performed using spiral multirow CT scanner (Siemens Somatom Sensation 10) with the following parameters: the extent fully covering all paranasal sinuses, detector configuration 10 x 0.75 mm, feed 4.1 mm, reconstruction thickness 1 mm, reconstruction increment 0.7 mm, kernel H60s for bone structures, or reconstruction thickness 4 mm, reconstruction increment 4 mm, kernel H31s for soft tissue structures. Secondary coronal and sagittal MPR's (multiplanar reconstructions) were then generated from original axial slices. No intravenous contrast media was required. Siemens CARE Dose 4D option was used to maximally reduce the X-ray dose. Since the aim of this study was to evaluate anatomical variations of sphenoidal sinuses septation only patients with no diseases within sphenoidal sinuses were included. All the subjects were Polish, with a mean age of 44 years, ranging from 18 to 84 years.

In our study there was only one septum in 41%, two septa in 33%, three septa in 22% and four septa in 4%. The total amount of sinuses depending on total amount of septa (including accessory septa) and it can be different in the anterior and posterior part of the sphenoidal sinus. We also notice that the highest and the broadest septum (main septum) was completely bony in 57% whilst in 47% it was partially membranous.

Performing CT of paranasal sinuses before surgery is essential to avoid potential complications resulting from anatomical variations.