Upper airway reconstruction using long‐range optical coherence tomography: Effects of airway curvature on airflow resistance

• Published in: Lasers in surgery and medicine Vol. 51; no. 2; pp. 150 - 160
• Main Authors: Kimbell, Julia S., Basu, Saikat, Garcia, Guilherme J.M., Frank‐Ito, Dennis O., Lazarow, Frances, Su, Erica, Protsenko, Dimitry, Chen, Zhongping, Rhee, John S., Wong, Brian J.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.02.2019
• Subjects: Adenoids - pathology; adenotonsillectomy; Aerodynamics; Air flow; Airway management; Airway Obstruction - diagnostic imaging; Airway Obstruction - etiology; Airway Obstruction - surgery; Airway Resistance; Child; Child, Preschool; Computational fluid dynamics; Computer applications; Computer Simulation; Corrosion resistance; Curvature; Diagnostic software; Diagnostic systems; Endoscopes; Endoscopy; Esophagoscopy; Female; Flow resistance; Fluid flow; Humans; Hydrodynamics; Hypertrophy; Image reconstruction; K-omega turbulence model; Lasers; long‐range optical coherence tomography; Male; Medical imaging; obstructive sleep apnea; Optical Coherence Tomography; Palatine Tonsil - pathology; pediatric airway; Pressure drop; Rank tests; Reconstructive Surgical Procedures; Respiration; Respiratory tract; Simulation; Tomography; Tomography, Optical Coherence; Turbulence models; obstructive sleep apnea; computational fluid dynamics; long-range optical coherence tomography; pediatric airway; adenotonsillectomy
• ISSN: 0196-8092; 1096-9101; 1096-9101
• DOI: 10.1002/lsm.23005

Objectives Adenotonsillectomy (AT) is commonly used to treat upper airway obstruction in children, but selection of patients who will benefit most from AT is challenging. The need for diagnostic evaluation tools without sedation, radiation, or high costs has motivated the development of long‐range optical coherence tomography (LR‐OCT), providing real‐time cross‐sectional airway imaging during endoscopy. Since the endoscope channel location is not tracked in conventional LR‐OCT, airway curvature must be estimated and may affect predicted airway resistance. The study objective was to assess effects of three realistic airway curvatures on predicted airway resistance using computational fluid dynamics (CFD) in LR‐OCT reconstructions of the upper airways of pediatric patients, before and after AT. Methods Eight subjects (five males, three females, aged 4–9 years) were imaged using LR‐OCT before and after AT during sedated endoscopy. Three‐dimensional (3D) airway reconstructions included three airway curvatures. Steady‐state, inspiratory airflow simulations were conducted under laminar conditions, along with turbulent simulations for one subject using the k‐ω turbulence model. Airway resistance (pressure drop/flow) was compared using two‐tailed Wilcoxon signed rank tests. Results Regardless of the airway curvatures, CFD findings corroborate a surgical end‐goal with computed post‐operative airway resistance significantly less than pre‐operative (P < 0.01). The individual resistances did not vary significantly for different airway curvatures (P > 0.25). Resistances computed using turbulent simulations differed from laminar results by less than ∼5%. Conclusions The results suggest that reconstruction of the upper airways from LR‐OCT imaging data may not need to account for airway curvature to be predictive of surgical effects on airway resistance. Lasers Surg. Med. 51:150–160, 2019. © 2018 Wiley Periodicals, Inc.