Anatomical Variations of Paranasal Sinuses on Coronal CT-Scan in Subjects with Complaints Pertaining to PNS

Abstract

Introduction: In the era of Functional Endoscopic Sinus Surgery, precise knowledge of the anatomy and variations of paranasal sinus is essential for the surgeon. Computed tomography provides accurate evictions of the anatomy, the anatomical variants and the extent of the disease in and around the paranasal sinuses. Aim: To evaluate the anatomical variations of paranasal sinuses using direct coronal CT-scan and to assess the frequency of their occurrence. Materials and Methods: Over a period of 18 months, 100 consecutive patients referred for CT-scan of PNS region to Department of Radiodiagnosis, MMC&RI (KR Hospital) were evaluated for the presence of normal variants of the paranasal region. Unenhanced CT of the PNS was performed for these patients in the coronal plane, complemented by axial views in selected cases. Results: Deviated nasal septum was the most common variation in 62(62%) followed by sphenoid sinus septations in 49(49%). Other variations found were middle concha bullosa in 43 (43%) patients, paradoxical middle turbinate in 14 (14%), horizontal uncinate process in 43 (43%), over pneumatized ethmoidal bulla or giant bulla 35 (35%), frontal sinus septations in 31%. Superior concha bullosa in 20 (20%), prominent Agger nasi cells in 26 (26 %), Haller cells in 11 (11%), Onodi cells in 6 (6%), maxillary sinus septae in 12 (12%) and pneumatization of uncinate process in 5 (5%) patients. Conclusion: Anatomical variations of PNS are quite common. These variations must be identified by the radiologist in preoperative CT evaluation to reduce the risk of intraoperative complications. CT provides a virtual road map to the surgeon and helps improve success of management strategies.

Keywords

• anatomic variants
• functional endoscopic sinus surgery
• intraoperative complications
• sinusitis