Quantification of Nasal Septal Deviation With Computed Tomography Data

Characterization of anatomical variations of the nasal cavity in a subset of European patients and their impact on intranasal drug delivery

Anatomical 3D-printed nasal casts are valuable models to investigate intranasal drug deposition, providing preclinical data that cannot be obtained in animal models. However, these models are limited since they are often derived from a single patient or represent a mean of several groups. The present study aimed to better characterize the anatomical differences of the nasal cavity in a European sub-population and to assess the potential impact of anatomical variations on intranasal deposition by medical devices. Ninety-eight cranial computed tomography scans of patients were selected and analyzed in 2D and 3D conformations. They showed symmetry of cavities and a high level of heterogeneity of measurements, especially volume and area, in the population. Three anatomical groups with distinct nasal geometry were identified and 3D nasal casts of the most representative patient of each group were printed. Fluorescein was administered using three medical devices: a nasal spray, a sonic jet nebulizer and a prototype mesh-nebulizer. The deposition profiles were compared with the Aeronose® as a reference. Our results show that anatomical variations influenced the deposition profiles depending on the device, with a higher variation with spray and the mesh-nebulizer. This work emphasises the importance of anatomical parameters on drug intranasal deposition and the need to evaluate inhaled drugs on different 3D nasal casts reflecting the target population.

Nasal Airway Volumes are More Asymmetric in Skeletally Mature Patients With Cleft lip and Palate Than Controls on 3-Dimensional Analysis

BACKGROUND

This study assesses nasal airway volumes in skeletally mature patients with CLP and healthy controls and examines the relationship among nasal volumes, cleft laterality, and facial asymmetry.

METHODS

Computed tomography images from patients with CLP and controls were analyzed using Mimics Version 23.0 (Materialise, Leuven, Belgium). Relationships among nasal airway volume, cleft laterality, and facial asymmetry were compared.

RESULTS

The 89 patients in this study included 66 (74%) CLP and 23 (17%) controls. Nasal airway volumes in CLP were more asymmetric than controls (26.8±17.5% vs. 17.2±14.4%; P=0.015). In UCLP, the smaller nasal airway was on the cleft side 81% of the time (P<0.001). Maximum airway stenosis was on the cleft side 79% of the time (P<0.001), and maximum stenosis was on the same side as the smaller airway 89% of the time (P<0.001). There was a mild linear relationship between nasal airway asymmetry and maximum stenosis (r=0.247, P=0.023). On 3-dimensional image reconstruction, the septum often bowed convexly into the cleft-sided nasal airway with a caudal deviation towards the noncleft side. Nasal airway asymmetry was not associated with facial midline asymmetry (P>0.05).

CONCLUSION

The nasal airway is more asymmetric in patients with cleft lip and palate compared with the general population, with the area of maximum stenosis usually occurring on the cleft-sided airway. In patients with unilateral cleft lip and palate, the septum often bows into the cleft side, reducing the size of that nasal airway. Nasal airway asymmetry did not correlate with facial asymmetry.

Correlation of maximal nasal septal deviation with deviation at the maxillary insertion

PURPOSE

It is unclear if septal deviation at the insertion points to the nasal cavity is associated with the overall septal deviation. This study aimed to assess septal deviation at the cribriform plate (CP) and maxillary crest (MC) using CT scans and to see if there was any correlation with overall septal deviation.

METHODS

All consecutive CT sinus scans between January 2020 and December 2021 were retrospectively reviewed. Patients were excluded if they had a history of head, nasal or facial trauma, or any previous nasal surgical procedure. Angles between the septum and MC and the septum and CP as well as maximal angle of septal deviation (MSD) were measured.

RESULTS

A total of 70 scans were included in the final analysis. The mean MSD was 8.14°. The mean septal deviation was 0.89° at the CP and 2.02° at the MC. The correlation coefficient between the deviation at the CP and MSD was 0.025 and between the deviation at the MC and MSD was 0.321.

CONCLUSION

Our data reveal a positive correlation between septal deviation at the floor of the nose and overall septal deviation; this was not observed at the septal deviation at the roof. This could be explained due to the inherent tilt in the cribriform plate or by earlier ossification and fixation of the septum during its development at its insertion to the roof, thereby allowing further growth and potential for deviation of the lower part of the septum and its insertion to the floor.

Correlation Analysis of Nasal Septum Deviation and Results of AI-Driven Automated 3D Cephalometric Analysis

The nasal septum is believed to play a crucial role in the development of the craniofacial skeleton. Nasal septum deviation (NSD) is a common condition, affecting 18-65% of individuals. This study aimed to assess the prevalence of NSD and its potential association with abnormalities detected through cephalometric analysis using artificial intelligence (AI) algorithms. The study included CT scans of 120 consecutive, post-traumatic patients aged 18-30. Cephalometric analysis was performed using an AI web-based software, CephX. The automatic analysis comprised all the available cephalometric analyses. NSD was assessed using two methods: maximum deviation from an ideal non-deviated septum and septal deviation angle (SDA). The concordance of repeated manual measurements and automatic analyses was assessed. Of the 120 cases, 90 met the inclusion criteria. The AI-based cephalometric analysis provided comprehensive reports with over 100 measurements. Only the hinge axis angle (HAA) and SDA showed significant (p = 0.039) negative correlations. The rest of the cephalometric analyses showed no correlation with the NSD indicators. The analysis of the agreement between repeated manual measurements and automatic analyses showed good-to-excellent concordance, except in the case of two angular measurements: LI-N-B and Pr-N-A. The CephX AI platform showed high repeatability in automatic cephalometric analyses, demonstrating the reliability of the AI model for most cephalometric analyses.

Three-dimensional structure of the basal lamella of the middle turbinate

The middle turbinate’s basal lamella (3BL) is a variable landmark which needs to be understood in endoscopic transnasal skull base surgery. It comprises an anterior frontal and a posterior horizontal part and appears in its simplest depiction to be “L”-shaped, when viewed laterally. In this study we analyzed its 3D morphology and variations focusing on a precise and systematic description of the anatomy. CBCTs of 25 adults, 19 cadavers and 6 skulls (total: 100 sides) were investigated with the 3DSlicer software, creating 3D models of the 3BL. We introduced a novel geometrical classification of the 3BL’s shape, based on segments. We analyzed their parameters and relationship to neighboring structures. When viewed laterally, there was no consistent “L”-shaped appearance of the 3BL, as it is frequently quoted. A classification of 9 segment types was used to describe the 3BL. The 3BLs had in average of 2.95 ± 0.70 segments (median: 3), the most frequent was the horizontal plate (23.05% of all segments), next a concave/convex plate (22.71%), then a sigma plate (22.37%). Further types were rare. We identified a horizontal plate in 68% of all lateral views whilst 32% of the 3BLs were vertical. A sigma–concave/convex–horizontal trisegmental 3BL was the most common phenotype (27%). Globally, the sigma–concave/convex pattern was present in 42%. The 3BL adhered the ethmoidal bulla in 87%. The segmenting method is eligible to describe the 3BL’s sophisticated morphology.