Ethnic Variation of Sinonasal Anatomy on CT Scan and Volumetric Analysis

Abstract

To determine Ethnic differences in the frequency of the relatively common anatomical variants along with difference in anatomy of sinonasal region with surgical importance. A study was conducted to determine the frequency of anatomical variants, volumes of paranasal sinuses using computed tomography and to identify any difference between Group A consisting of people of Indian subcontinent and Group B consisting of people from north east Asian region. Volumetric analysis done using cumulative of area multiplied by slice thickness. The results were compared using Chi square test, p value < 0.05 was considered statistically significant. Among the common and uncommon anatomical variants (Agger nasi, pneumatized uncinate, concha bullosa etc.) there was no significant difference between the two groups. In both the groups Keros Type 1 was the most common type of ethmoid roof seen. On volumetric analysis sphenoid sinus volume was found to be higher in Indians without mongoloid features. Hence it's ideal that in this era of endoscopic sinus surgery we tailor make approaches to address individual anatomical variation.

Keywords: Anatomic variation; CT-scan; Ethnic; Paranasal sinuses; Volumetric analysis.

Fig. 1

Measurement of sinus volumes

Fig. 2

Inter-laminar distance (between lamina and lamina). It is taken at level of bulla where lamina forms the lateral wall

Fig. 3

Measurement of distance from anterior nasal spine to anterior and posterior wall of sphenoid and distance between anterior and posterior wall of sphenoid

Fig. 4

Depth of cribriform plate. It is taken from medial end of fovea ethmoidalis up to lateral end of cribriform plate