Computational fluid dynamics of the airways after left‐upper pulmonary lobectomy: A case study

• Published in: International journal for numerical methods in biomedical engineering Vol. 37; no. 7; pp. e3462 - n/a
• Main Authors: Tullio, Marta, Aliboni, Lorenzo, Pennati, Francesca, Carrinola, Rosaria, Palleschi, Alessandro, Aliverti, Andrea
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.07.2021; Wiley Subscription Services, Inc
• Subjects: Aerodynamics; Air flow; Application; Applications; Computational fluid dynamics; Computed tomography; Computer applications; Fluid dynamics; Hydrodynamics; imaged‐based; Local flow; Lung cancer; Mathematical models; Patients; Pressure; Pulmonary functions; pulmonary lobectomy; Quantitative analysis; Respiratory function; Secondary flow; Shear stress; Thorax; Trachea; tracheobronchial tree modeling; Velocity; Ventilation; Wall pressure; Wall shear stresses; imaged-based; computational fluid dynamics; pulmonary lobectomy; tracheobronchial tree modeling
• ISSN: 2040-7939; 2040-7947; 2040-7947
• DOI: 10.1002/cnm.3462

Pulmonary lobectomy is the gold standard intervention for lung cancer removal and consists of the complete resection of the affected lung lobe, which, coupled with the re‐adaptation of the remaining thoracic structures, decreases the postoperative pulmonary function of the patient. Current clinical practice, based on spirometry and cardiopulmonary exercise tests, does not consider local changes, providing an average at‐the‐mouth estimation of residual functionality. Computational Fluid Dynamics (CFD) has proved a valuable solution to obtain quantitative and local information about airways airflow dynamics. A CFD investigation was performed on the airway tree of a left‐upper pulmonary lobectomy patient, to quantify the effects of the postoperative alterations. The patient‐specific bronchial models were reconstructed from pre‐ and postoperative CT scans. A parametric laryngeal model was merged to the geometries to account for physiological‐like inlet conditions. Numerical simulations were performed in Fluent. The postoperative configuration revealed fluid dynamic variations in terms of global velocity (+23%), wall pressure (+48%), and wall shear stress (+39%). Local flow disturbances emerged at the resection site: a high‐velocity peak of 4.92 m/s was found at the left‐lower lobe entrance, with a local increase of pressure at the suture zone (18 Pa). The magnitude of pressure and secondary flows increased in the trachea and flow dynamics variations were observed also in the contralateral lung, causing altered lobar ventilation. The results confirmed that CFD is a patient‐specific approach for a quantitative evaluation of fluid dynamics parameters and local ventilation providing additional information with respect to current clinical approaches. Quantitative and clinically relevant information were provided for a left‐upper lobectomy patient, using a subject‐specific computational approach. The reconstruction of the airway tree revealed severe anatomical distortions after surgery. Numerical simulations demonstrated highly disturbed fluid dynamics conditions in the whole structure with respect to the preoperative condition. At the resection site and at the trachea, local increases of velocity, secondary flows, pressure, and wall shear stress were found. Consequences were observed also in the contralateral lung, determining altered lobar ventilation.