A 3D printed C-shape external airway splint composite skin flap for tracheal reconstruction: State-of-the-art...

Repair of long-segment tracheal defects remains a challenge worldwide. In this study, we proposed a new strategy for tracheal reconstruction and verified the feasibility of this strategy in a canine model of tracheal defects.

An external airway splint was designed and fabricated using three-dimensional (3D) printing. The skin flap was rotated as a tube and suspended by an external airway splint to construct tracheal substitutes. In vitro, the tracheal substitutes were tested under a negative pressure gradient (-10 mmHg, -20 mmHg, and -30 mmHg). In vivo, nine canines conducted long-segment tracheal resection (5 cm) and reconstructed. Quality of life was evaluated using the Westley clinical croup scale, and radiography was performed to evaluate the patency of the trachea.

Three kinds of "C" shape external splint with different opening distances (5 mm, 10 mm, and 15 mm) were designed and fabricated. In vivo, with a C5 mm tracheal substitute, all canines' tracheal lumen recovered patency postoperation and canines can move normally immediately. The median survival time of all canines was 41 days. Radiography showed that the degree of patency was more than 40% at 4 weeks postoperatively. The main reason for tracheal obstruction was the growth of fur rather than granulation tissue. Histological examination indicated that the skin flaps had excellent viability, with extensive vascularization.

The "C" shape external airway splint could prevent the skin flap from collapsing without the need for an internal tracheal stent, indicating that 3D printed C-shape external airway splint composite skin flap may be a promising method for tracheal reconstruction.