Structural optimization of biodegradable tracheal stent based on mechanical properties of trachea.

Tracheal stent implantation serves as a critical intervention for tracheal stenosis, where biodegradable magnesium (Mg) alloy stents have emerged as promising alternatives due to their ability to eliminate long-term complications associated with permanent stents. However, the uneven stress distribution on the stent often leads to premature failure through localized rapid degradation and structural collapse. This study systematically investigated the biomechanical interactions between biodegradable stents and tracheal tissues to guide optimized stent design. The mechanical properties of tracheal cartilage under physiological curvature conditions were quantitatively characterized using custom-designed tissue fixtures. Finite element analysis was employed to simulate Mg alloy stent interaction with the trachea during both normal breathing and coughing, which revealed that the stent's regions adjacent to the cartilage and membranous wall junction are high-risk regions for fractures. To address these challenges, the non-uniform stent design was proposed to enhance radial support and distribute stresses more evenly, thereby improving the resistance to localized degradation and premature fracture. The findings provide biomechanical insights and technical strategies for the development of biodegradable tracheal stents.