The course of the main septum in the sphenoid sinuses - evaluation before the FESS.

The purpose of this study was to determine the course of the main septum (MS) in the sphenoid sinuses in the adult population. Materials and Methods: 296 patients (147 females, 149 males), who did not present any pathology in the paranasal sinuses, were included in this retrospective analysis of the computed tomography (CT) scans. Spiral CT scanner (Siemens Somatom Sensation 16) was used in order to glean the images of the paranasal sinuses, using standard procedure, in the option Siemens CARE Dose 4D, without using any contrast medium. Secondary reconstructions of the sagittal and frontal planes were obtained using multi- plans reconstruction (MPR) tool after obtaining transverse planes in the first instance. R e s u l t s: The course of the MS changed the most often from the anterior to the posterior part of the sphenoid sinuses. Such situation took place in 83.78% of the patients, in 32.43% of whom a clear shift to the lateral side was noticed only in the posterior part of the MS: in 18.24% of the patients to the right side, and in 14.19% of the patients to the left side. In 17.57% of the patients the lateral shift was visible in both anterior and posterior parts of the septum, where in 9.46% of the patients it was from the left side to the right, whereas in 8.11% of the patients the shift took place from the right side to the left. The MS had the shape of the letter 'C' in 22.29% of the cases, and 11.82% had the typical shape of the letter 'C,' and in 10.47% of the patients it paralleled the inverted letter 'C' (upside down). Amongst the types of the MS shifting directions the rarest was the MS that resembled the letter 'S' - 11.48% of the patients. In 5.74% of the cases it looked like the typical letter 'S,' and in 5.74% of the cases it was similar to the inverted letter 'S.' Only 16.22% of the cases had the MS that did not change its course nor its shape and ran medially in the sagittal plane from the anterior to the posterior part of the sinuses. Conclusions: In furtherance of reducing the risk of problems occurring during a surgery in the paranasal sinuses, it is prudent to have a CT scan done in all the patients beforehand, due to the high prevalence of the anatomical variations in the sinuses.