Comparison of Postoperative Airflow Changes in Slide Tracheoplasty Across Surgical Techniques Using Computational Fluid Dynamics.

OBJECTIVE

Use computational fluid dynamics (CFD) modeling to analyze airflow before and after slide tracheoplasty in a three-dimensional (3D) printed model of congenital tracheal stenosis and to compare surgical techniques.

STUDY

DESIGN

Comparative anatomic and physiologic study using 3D printed trachea models.

SETTING

Tertiary children's hospital and mechanical engineering lab.

METHODS

Slide tracheoplasty was performed on 3D printed models of congenital tracheal stenosis using three variations of tracheal transection incision angle (90°, 45° beveled superior to inferior, and 45° beveled inferior to superior). Postoperative computed tomography scans were used for CFD analysis. Quasi-steady simulations of peak inhalation and exhalation were run to calculate airway resistance, velocity, and energy dissipation. Statistical analysis was performed using one-way analysis of variance and unpaired two-tailed t tests.

RESULTS

Slide tracheoplasty was performed three times for each technique for nine total repaired tracheas. CFD simulations of each model at peak inhalation and exhalation were compared to preoperative controls. Slide tracheoplasty yielded reductions in all metrics postoperatively compared to preoperative controls (P < .001) without differences between incision types (P > .05). During inhalation, airway resistance decreased by 1.33 Pa/(mL/s) (62%, 95% CI: 1.26-1.39), maximum velocity by 7.23 m/s (36%, 95% CI: 6.20-8.26), and energy dissipation by 8.45 mW (63%, 95% CI: 7.90-9.01). During exhalation, airway resistance decreased by 1.1 Pa/(mL/s) (64%, 95% CI: 1.03-1.17), maximum velocity by 7.56 m/s (37%, 95% CI: 6.47-8.64), and energy dissipation by 8.45 mW (61%, 95% CI: 8.87-10.80).

CONCLUSION

A beveled tracheal transection incision yields a longer postoperative trachea without compromising physiologic airflow improvements, therefore warrants consideration over a straight incision when choosing surgical technique.