Two-stage end-to-end reconstruction of long-segment tracheal defects with a bioabsorbable scaffold grafting technique in a canine model

Background: When a long segment of trachea is resected and grafted with a bioabsorbable scaffold, chronic contraction of the graft occurs, leading to substantial delayed native tracheal axial approximation. This phenomenon may allow for safe two-stage end-to-end tracheal reconstruction of large tracheal defects. We performed this trial to confirm that delayed tracheal axial approximation occurs in a mature animal model and to test the surgical feasibility of two-stage end-to-end tracheal reconstruction. Methods: Five dogs (weight, 19 to 21 kg) underwent cervical tracheal resection and replacement (50 mm) with use of a conduit of a copolymer of L-lactide and ε-caprolactone reinforced with polyglycolic acid. A silicone stent (70 mm) was placed to prevent graft collapse. Postoperative bronchoscopy and computed tomography were scheduled to assess tracheal approximation and graft absorption. Native tracheal end-to-end reconstructive surgical procedures were planned at 9 months, when the defect that had been grafted decreased to less than 25 mm in length. Results: Suture-related granulation tissue in the airway of one dog, which prevented operation. The grafted area length in four animals ranged from 19 mm to 23 mm 9 months after operation. These animals then underwent tracheal reconstructive surgical procedures consisting of resection of the grafted area and end-to-end native tracheal reanastomosis without postoperative stent placement. All surgical procedures were successful, and there were no procedural deaths or postoperative complications after the second operation for as long as 2 months. Conclusions: Delayed tracheal axial approximation after bioabsorbable grafting was confirmed in a mature animal model and allowed two-stage end-to-end tracheal reconstruction of large tracheal defects.