While advancements have been made in equine upper airway surgery, many unknowns remain about the specific influence of surgery on obstructive airway disorders. Computational fluid dynamics (CFD) is useful for analyzing obstructive airway disorders and surgeries in human medicine and it warrants further development for application in the equine patient. The objective of this study was to apply CFD analysis to an equine head inhalation model replicating recurrent laryngeal neuropathy and four surgical techniques. CFD was hypothesized to corroborate the order of the states based on impedance and to provide a numerically similar impedance value to the experimental results. Additionally, it would provide insights into the fluid mechanical changes associated with each procedure on a finite scale. The CFD and experimental model resulted in the partial arytenoidectomy having the lowest impedance in this case. While this procedure did have the largest rima glottis area, the remaining procedural order was not dictated by rima glottis area. Recurrent laryngeal neuropathy and the combined laryngoplasty with corniculectomy showed negative pressure concentration on the luminal surface of the left arytenoid cartilage, which indicates a greater collapsing force on the tissues. Narrowing within the caudal larynx at the ventricles showed increased negative pressure and higher velocities in the procedures with greater impedance while the partial arytenoidectomy had more uniform pressure and velocity. This specific experimental head model contradicts previous flow studies, however the CFD model reflected the experimental findings for procedure of least impedance and provided insights into these discrepancies for this case.
