Prevalence of pneumatisation patterns of Onodi cells among the North-East Indian population

Abstract Background The posterior ethmoid sinuses have a complex anatomy and a highly variable normal structure. The posterior ethmoid Onodi cell needs careful assessment because of its proximity to the optic nerve and the internal carotid artery canal. Recognising the distinctions is essential for optimal pre-op preparation. Sphenoid sinus surgery can now be performed without worrying about compromising vital structures like the internal carotid artery or optic nerve. Preoperative radiological assessment is a quick and easy way to check for ethmoid cell pneumatisation differences. Aim and objectives To determine the pneumatisation patterns of Onodi cells among the North-East Indian population using 16-slice multidetector computed tomography (MDCT). Results Nine-hundred MDCT paranasal sinuses were analysed over a period of 0–2 years, out of which 220 cases showed the presence of Onodi cell. Type I were 89 cases (40.45%, CI 32.00–48.90), Type II were 128 cases (58.18%, CI 49.72–66.63), and 3 cases with Type III cell (1.36%, CI 0.18–2.54). Conclusion The most prevalent pneumatisation pattern is Type II. The pneumatisation patterns of Onodi cells can be best detected and evaluated by multiplanar MDCT imaging. Sinus surgeons need a firm grasp of pneumatisation patterns to avoid damaging the optic nerve and internal carotid artery canal during operations.