Analyzing nasal septal deviations to develop a new classification system: a computed tomography study using MATLAB and OsiriX.

IMPORTANCE Accurately characterizing nasal septal deviations is valuable for surgical planning, classifying nasal septal deviations, providing a means to accurately perform outcomes research, and understanding the causes of chronic conditions. OBJECTIVE To determine and quantify regions of septal deformity that can be used to develop a comprehensive classification system. DESIGN, SETTING, AND PARTICIPANTS A retrospective case series study was conducted at an academic tertiary care hospital. Sixty-four participants were selected based on a convenience sample of computed tomography (CT) scans of the paranasal sinuses and midface available between June 29, 2011, and August 16, 2012. Exclusion criteria consisted of incomplete or inadequate CT series. The most recent CT scans were chosen for analyses regardless of the indication for imaging. Digital Imaging and Communications in Medicine format bitmap file–formatted data were obtained and analyzed using MATLAB and OsiriX. The line to curve ratio, deviation area, and root mean square (RMS) values of the septal contour vs the ideal straight septum fit were calculated. Analysis was performed to detect significant differences (P < .05) using the 3 measures.MAIN OUTCOMES AND MEASURES Quantitative analysis of nasal septal deviation.RESULTS The population consisted of 50 male and 14 female patients aged 3 to 83 years(mean, 42 years). Mean line to curve ratios, areas, and RMS values were highest in contours that intersected the perpendicular plate–vomer junction, with a mean line to curve ratio of1.04 and mean deviated area of 627.16 arbitrary units (P = .02). Maximal deviation areas were also seen midway from the perpendicular plate–vomer junction to the nasal spine with a mean area of 577.31 arbitrary units (P = .01). The RMS values were significantly elevated along the crista galli and perpendicular plate–vomer junction (P < .05).CONCLUSIONS AND RELEVANCE Maximum septal deviation is seen at the perpendicular plate–vomer junction and in the regions near the crista galli and anterior nasal spine.Deviation area and RMS values are important measures to characterize septal deviations.Understanding septal deviations can aid in developing a functional classification system of nasal septal deviations for clinical use and a means to better record and compare surgical outcomes.