Computational fluid dynamics (CFD) shows promise in predicting the influence of surgeries on human airflow mechanics, but has only been reported twice in equine applications. The reported study broadens this to four procedures for equine recurrent laryngeal neuropathy (RLN). The first objective of this study was to characterize the three-dimensional geometry of equine larynges replicating RLN and four subsequent surgical procedures under airflow conditions. The second objective was to evaluate the agreement between a CFD model and measured airflow characteristics. The last objective was to explore the anatomic distribution of pressure, velocity, and turbulent kinetic energy associated with RLN and each surgical procedure performed. Ten equine cadaveric larynges were tested in an instrumented box replicating inhalation during a computed tomographic exam. The pressure upstream and downstream (outlet) were measured. Image segmentation was then performed; files which were smoothed and remeshed for CFD modelling. CFD analysis using the experimentally measured outlet pressure were performed. The procedural order and calculated laryngeal impedance were compared to the experimental values. CFD agreed with the experimental portion of the study in determining the surgical procedure resulting in the lowest post-operative impedance in 9 out of 10 larynges. CFD calculated laryngeal impedance was approximately 0.7 times that of the experimental values. Areas of low pressure and high velocity were observed around luminal tissue irregularities. Peaks were associated with RLN, the corniculectomy and the partial arytenoidectomy. CFD modelling reliably determined the lowest impedance surgical procedure for each equine larynx. Future exploration may improve numerical accuracy.
