Abstract
BACKGROUND: Empty nose syndrome (ENS) is a controversial upper airway disorder most commonly associated with tissue loss from the inferior turbinates. The inferior meatus augmentation procedure (IMAP) has been shown to effectively reduce ENS symptoms in a durable manner, but the precise mechanisms that may govern this symptomatic improvement remain unknown. METHODS: Five patients with ENS who underwent bilateral IMAP via submucosal costal cartilage implant were assessed. Pre-implant and 6 months post-implant computed tomography (CT) imaging for each ENS patient was analyzed in a blinded fashion using computational fluid dynamics (CFD) modeling to investigate intrapatient changes in airflow parameters. RESULTS: Following surgery, ENS patients have significantly improved symptoms as indexed by Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) scoring (pre-implant: 14.00 ± 4.06 [mean ± standard deviation]; 95% confidence interval [CI], 10.44 to 17.56; post-implant: 4.8 ± 2.77; 95% CI, 2.37 to 7.23; Cohen's d = 2.64; p = 0.02). Using CFD, a significant shift in nasal airflow patterns was observed, where airflow deviates away from the middle meatus upon hitting the implant (pre-implant: 67.13% ± 11.14%; 95% CI, 60.22% to 74.04%; post-implant: 46.18% ± 12.81%; 95% CI, 38.23% to 54.12%; d = 1.74; p < 0.05) toward the inferior meatus (pre-implant: 30.55% ± 11.29%; 95% CI, 23.55% to 37.55%; post-implant: 42.59% ± 9.60%; 95% CI, 36.63 to 48.54%; d = 1.14; p < 0.05). No significant changes were found in nasal resistance (pre-implant: 0.102 ± 0.015; 95% CI, 0.092 to 0.112 Pa*s/mL; post-implant: 0.105 ± 0.041; 95% CI, 0.081 to 0.130 Pa*s/mL). In addition, the improvement of ENS6Q scoring significantly correlated with percent reduction in aberrant airflow through the middle meatus (R(2) = 0.60, p = 0.04). CONCLUSION: This study supports our prior working hypothesis that disordered vectors of nasal airflow congregate in the middle meatus contribute to ENS symptoms, not nasal resistance. Moreover, these data illuminate a paradoxical, but consistent, restoration of nasal airflow to the inferior meatus following the replacement of turbinate tissue volume in the inferior meatus via IMAP surgery, potentially due to the Coandă effect.