Characterization of postoperative changes in nasal airflow using a cadaveric computational fluid dynamics model: supporting the internal nasal valve.
IMPORTANCE: Collapse or compromise of the internal nasal valve (INV) results in symptomatic nasal obstruction; thus, various surgical maneuvers are designed to support the INV. OBJECTIVE: To determine the effect on nasal airflow after various surgical techniques focused at the level of the INV and lateral nasal sidewall. DESIGN AND SETTING: A fresh cadaver head was obtained and underwent suture and cartilage graft techniques directed at the level of the INV using an external approach. Preoperative and postoperative digital nasal models were created from the high-resolution, fine-cut, computed tomographic imaging after each intervention. Isolating the interventions to the level of the INV, we used computational fluid dynamic techniques to calculate nasal resistance, nasal airflow, and nasal airflow partitioning for each intervention. INTERVENTION: Suture and cartilage graft techniques. MAIN OUTCOMES AND MEASURES: Nasal airflow, nasal resistance, and partitioning of airflow. RESULTS: Using the soft-tissue elevation model as baseline, computational fluid dynamic analysis predicted that most of the suture and cartilage graft techniques directed toward the nasal valve improved nasal airflow and partitioning while reducing nasal resistance. Specifically, medial and modified flare suture techniques alone improved nasal airflow by 16.9% and 15.1%, respectively. The combination of spreader grafts and modified flare suture improved nasal airflow by 13.2%, whereas spreader grafts alone only improved airflow by 5.9%. The largest improvements in bilateral nasal resistance were achieved using the medial and modified flare sutures, outperforming the combination of spreader grafts and modified flare suture. CONCLUSIONS AND RELEVANCE: Techniques directed at supporting the INV have tremendous value in the treatment of nasal obstruction. The use of flare sutures alone can address dynamic valve collapse or upper lateral cartilage incompetence without gross disruption of the nasal architecture. Using computational fluid dynamic techniques, this study suggests that flare sutures alone may improve flow and reduce resistance when placed medially, surpassing spreader grafts alone or in combination with flare sutures. The longevity of these maneuvers can only be assessed in the clinical setting. Studies in additional specimens and clinical correlation in human subjects deserve further attention and investigation. LEVEL OF EVIDENCE: NA.
Shadfar, S; Shockley, WW; Fleischman, GM; Dugar, AR; McKinney, KA; Frank-Ito, DO; Kimbell, JS
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