Measurement of deformation rate in nasal septum deviation by three-dimensional computer tomography reconstruction and its application in nasal septoplasty endoscopic surgery

Objective evaluation of caudal deviation of the nasal septum and selection of the appropriate septoplasty technique

OBJECTIVE

Several methods have been reported to correct caudal deviation of the nasal septum, including open septorhinoplasty (OSR) and septoplasty with Killian incision (KI). In general, OSR is applied instead of KI for caudal deviation. However, there is little objective evidence own on the effects of OSR and KI for caudal deviation. In this study, we compared surgical outcomes between OSR and KI by quantifying nasal septum deviation using two simple and objective parameters on routine paranasal sinus CT scans.

METHODS

We retrospectively analyzed 18 patients who underwent OSR and 11 patients who underwent septoplasty with KI between April 2006 and October 2019. Caudal deviation was defined on the basis of the "Anterior-posterior Position of the most deviated point of the nasal septum (AP)," which was measured on computerized tomography. The deformation rate (DR) of the nasal septum was also calculated. Nasal airway resistance and visual analogue scale (VAS) score for nasal obstruction were examined.

RESULTS

The AP was significantly correlated with the VAS score (r=-0.58, p=0.017). The DR in patients with caudal septal deviation was significantly decreased by OSR (0.14±0.06 to 0.03±0.03, p=0.004), but not by KI (0.09±0.08 to 0.04±0.03, p=0.25). OSR also improved nasal airway resistance (1.10±0.44 to 0.42±0.15, p=0.02), and the VAS score (79.11±14.74 to 5.78±7.89, p=0.004).

CONCLUSION

Nasal obstruction is more severe in patients with the caudal deviation. OSR corrects caudal deviation of the nasal septum more effectively than does KI. The AP could be useful for the evaluation of the deviation of the nasal septum and help in selecting the appropriate septoplastic technique.

Nasal cavity airflow: Comparing laser doppler anemometry and computational fluid dynamic simulations

Objective parameters to assess the physical flow conditions of breathing are scarce and decisions for surgery, e.g. nasal septum correction, mainly rely on subjective surgeon judgment. To define decision supporting parameters, we compare laser Doppler anemometry (LDA) and numerical computational fluid dynamic simulations (CFD) of the airflow velocity vector fields in the nasal cavity, including lattice Boltzmann (LB) and finite volume methods (FVM). The simulations are based on an anonymous patient CT dataset with septal deviation. LDA measurements are preformed using a 3D printed model. Nasal airflow geometry is randomly deformed in order to approximate surgical changes. The root-mean-square velocity error near the nasal valve of laser Doppler anemometry and lattice Boltzmann simulations is 0.071. Changes in geometry similarly affect both measurement and simulation.

Nasal Floor Asymmetry Is Associated With Nasal Obstruction

PURPOSE

The role of morphologic characteristics of the nasal cavity in nasal obstruction is not yet sufficiently understood. The aim of this study was to determine which morphometric parameters of the nasal cavity severely impair nasal breathing and when.

PATIENTS AND METHODS

In a hospital-based, computed tomography-morphometric cross-sectional study, we evaluated computed tomography coronal scans of patients with known nasal obstruction scheduled to undergo functional nasal surgical procedures (cases) and trauma patients without facial involvement or known nasal obstruction (controls). The primary predictor variable was case versus control. In both groups, we measured and compared the piriform aperture width; nasal floor canting; piriform aperture vertical height, height-width ratio, and total cross-sectional area; height difference between the right and left nasal floors; and nasal septal thickness; as well as age and gender differences. Metric data means, standard deviations, and 95% confidence intervals were calculated and analyzed.

RESULTS

The sample was composed of 60 patients evenly divided between cases and controls. Of these, 30 were men. The average age of the cases and controls was 27.4 ± 7.8 years and 38.5 ± 18.6 years, respectively (P < .001). The differences in piriform aperture width were not statistically significant between cases and controls (23.3 ± 1.9 mm and 23.8 ± 1.7 mm, respectively; P > .2). In contrast, we noted statistically significant differences between cases and controls in nasal floor canting (5.4° ± 4.6° and 1.8° ± 1.5°, respectively; P < .001) and height difference between the right and left nasal floors (1.8 ± 1.2 mm and 1.0 ± 0.7 mm, respectively; P = .002).

CONCLUSIONS

Nasal floor canting of 3° or greater and a height difference between the right and left nasal floors of 1.5 mm or greater may contribute to the etiology of clinically relevant nasal obstruction. A piriform aperture width of 22 mm or less may be considered narrow. Future studies can determine when and how exactly to surgically address a clinically relevant narrow piriform aperture and nasal floor canting.