Computational fluid dynamics and NOSE scale to assess nasal respiratory function, and correlation with linear maxillary measurements after surgically assisted rapid maxillary expansion.

Nasal obstruction is common in patients with a transverse maxillary deficiency. The aim of this study was to determine the variation in nasal airway resistance in adult patients with a transverse maxillary deficiency before and after surgically assisted rapid maxillary expansion (SARME) by computational fluid dynamics (CFD) using computed tomography scans, and to correlate this variation with maxillary linear measurements obtained by means of plaster models. The subjective symptoms of nasal obstruction were also analysed using a visual analogue scale (VAS) for nasal breathing and the Nasal Obstruction Symptom Evaluation (NOSE) scale. There was a median reduction of 21% in nasal airway resistance post SARME (P = 0.002). The NOSE scale score decreased (P < 0.001) and nasal breathing quality VAS scores increased in both nostrils (P < 0.001). Transverse measurements between the upper canines (C-C), premolars (PM-PM), and molars (M-M), and maxillary perimeter showed significant increases (P < 0.001), while the anteroposterior maxillary arch length showed a significant decrease (P = 0.016). An inverse proportional correlation was found between PM-PM and nasal airway resistance (r = -0.395; P = 0.034) and between M-M and nasal airway resistance (r = -0.383; P = 0.040). These results demonstrate that surgically expanding the posterior region of the maxilla results in decreased nasal airway resistance, decreased obstructive symptoms, and improved patient respiratory quality.