The Variant Anatomy of the Sphenoid Sinus as Seen in Patients Undergoing Paranasal Sinus Computed Tomography Imaging at the Nairobi Hospital

Abstract

Background: The anatomy of the sphenoid sinus is of great utility to otorhinolaryngologists and neurosurgeons. It is an important landmark in minimal access surgery of the anterior and middle cranial fossa. Knowledge of the variant anatomy is important to reduce surgery related complications. Computed tomography (CT) scan of the paranasal sinuses is the imaging modality of choice used in assessing this anatomy. Objective: To determine the variant anatomy of the sphenoid sinus in patients undergoing paranasal CT scan evaluation at The Nairobi Hospital Study Design: This was a descriptive cross-sectional study. Study Setting: This study took place at The Nairobi Hospital Radiology Department Methodology: This study involved 123 participants aged 16 years and above who were recruited through consecutive sampling from all the patients sent for paranasal CT scan imaging at The Nairobi Hospital Radiology Department. The axial CT scan slices were standardized to 0.67mm cuts and coronal and sagittal orientations generated by computer reconfiguration. The variant anatomy was studied and characterized. Study Duration: This study was conducted from January 2022 to September 2023. Data Management and Analysis: Data was collected using a questionnaire and analyzed using SPSS version 22. Analysis of variance was carried out to determine the association between the anatomical variations and age distribution. Fischer’s exact test was used to compare between right, left and bilateral variations. A cut-off statistical significance was set at a P value of <0.05 for a 95% confidence interval. Results: the study included 55 males and 68 females with ages ranging from 18 years to 80 years. The mean age was 43.9 years +/- 14.3 years. The most common type of sellar pneumatization was the sellar variant (87.8%) with presellar variant representing 12.2% and no conchal variant seen in this study. The most common sellar variant was the complete one (65.7%) with the complete variant being more common in males (53.52%) than it was in females (46.48%). The sphenoid sinus invariably (97.6%) had septa. The most common type of Optic nerve protrusion was type 0 (left 30.1%, right 31.7%) and type 1 (left 43.9%, right 40.7%). Conclusion: This study confirms the variant anatomy of the sphenoid sinus. The complete. Sellar variant was more common in males. There was no internal carotid dehiscence. Recommendations: understanding the anatomy if the sphenoid sinus is important in performing safe surgery.