Evaluation of anatomical variants of sphenoid sinus by multidetector computed tomography

Abstract

Background: Para nasal sinuses are air-filled cavities present in facial bones. Sinusitis is a common medical problem affecting millions of people annually. CT screening of paranasal sinuses has the advantages of showing bony details and good soft tissue outlines. CT is valuable in the identification of variations in pneumatisation of sphenoid sinuses and characterization of sphenoid variations prior to FESS and trans-sphenoidal surgeries. Materials and Methods: This was a cross-sectional study conducted at Dr. PSIMS & RF, Chinnavutapalli. This study was done on SIEMENS SOMATOM EMOTION 16 slice spiral CT machine. We included a total of 100 patients clinically diagnosed with chronic sinusitis, who were referred for CT scan of PNS in our hospital. Results: Out of 100 patients, 52 males and 48 females. Most of the patients were in the 20-30 years age group comprising 55% of the study population. Presellar type of pneumatisation found in (83%), Postsellar type of pneumatisation (11%). Pneumatisation of pterygoid process (42%), anterior clinoid process (28%), greater wing of sphenoid (22%). Bilateral protrusion of internal carotid artery (19 cases), right side (5 cases) and on left side (3 cases). Protrusion of optic nerve noted in 21 cases, among these 14 bilaterally, (4) right N and (3) left side, maxillary nerve protrusion (16 cases), among these 8 (bilaterally), (5) right and (3) left side, Vidian nerve protrusion (20 cases), among these (8) bilaterally, (7) right and (5) left side. Conclusion: Computed Tomography plays an important role in visualization of variation in sphenoid sinus and its pneumatisation patterns and has re-emphasized the concept that variations especially in the sphenoid sinus region is the key factor in the causation of accidental damage to vital structures like ICA, Optic nerve, Maxillary nerve and Vidian nerve.