EVALUATION OF BASAL SPHENOID ANGLE AMONG ADULTS OF AFRICAN DESCENT USING TOMOGRAPHIC IMAGING

Background: The Basal Angle (BA) of the sphenoid represents an integral anthropological component of the radiological examination of the cranial floor which allows for the diagnosis of platybasia. As a developmental anomaly of the skull base, occipital bone and upper cervical vertebrae, platybasia is associated with changes in the depth of the posterior cranial fossa and the shape of the spheno-occipital region. Objective: To determine the average basal sphenoid angle and its relationship with the dimensions of the sphenoid sinus among adults of African origin using computerized tomography (CT). Method: Computerized tomography (CT) images of three hundred and twenty-three adult sphenoid sinuses of individuals with age ranging from 18 to 80 years, over a 5- year period were retrospectively studied at the Radiology Department of the University Teaching Hospital following institutional ethical approval. On a sagittal CT slide, the sphenoid BA was measured as the angle subtended between two lines on the cranial floor. Platybsia was defined as; BA greater than 143°. The anteroposterior, craniocaudal, and transverse diameters of the sphenoid sinus were measured, the extent of pneumatisation was noted, while sinus volume was calculated. Results: The BA of the sphenoid ranged from 88° to 157.9°with a mean BA of 124.70° ± 11.4. There was a statistically significant relationship between the BA and the craniocaudal diameter of the sphenoid sinus. Conclusions: Computerized tomography assessment of the sphenoid basal angle among Africans is lower than currently known. These values are also lower compared to results obtained using X-rays and among Caucasians. This emphasises the need for more studies on CT assessment of the skull base for the determination of an applicable African average for the sphenoid BA. This is relevant in the radiological identification of skull base malformations.