Nasal Morphometric Differences Associated with Septal Deviation Severity on Computed Tomography: A Cross-Sectional Anatomical Study.

INTRODUCTION

Nasal septal deviation (NSD) may coexist with variation in the surrounding nasal framework, but its association with nasal proportions and bony-pyramid geometry remains incompletely characterized. This study evaluated the associations of NSD severity and continuous nasal septal deviation angle (NSDA) with computed tomography (CT)-derived nasal morphometric parameters.

METHODS

This retrospective cross-sectional study included 150 adults, with 50 in each NSD severity category. HC3-robust analysis of covariance adjusted for age, sex, and deviation side was applied across nine morphometric outcomes with false discovery rate (FDR) correction. Secondary models treated NSDA as a continuous exposure. Reliability was assessed in a severity-balanced 50-case subset.

RESULTS

Adjusted group effects were significant for the frontal facial angle (FFA), the internasal angle (INA), both nasal bone length-to-nose length (NBL/NL) ratios, and root-based nose length (R-NL; FDR-adjusted p = 0.008-0.049). Severe deviation was associated with a lower INA and lower ratios than mild deviation, and with greater R-NL and FFA than moderate deviation. Continuous models confirmed a lower INA, lower ratios, and lower suture-based nasal bone length, and greater R-NL, per 5° higher NSDA. Decomposition indicated that the lower suture-based ratio was driven mainly by lower nasal-bone length, whereas the lower root-based ratio was driven mainly by greater nose length. Interobserver intraclass correlation coefficients were 0.870-0.970.

CONCLUSION

Greater NSD severity was associated with lower NBL/NL ratios and INA and greater R-NL in this severity-balanced cohort. These findings characterize anatomical covariation in nasal proportion and geometry; their value for surgical decision-making requires prospective evaluation.