Endoscopically Applied Biodegradable Stent in a Rabbit Model of Pediatric Tracheomalacia

Abstract

Objectives: A polydioxanone (PDO) stent has been developed to treat tracheomalacia in pediatric patients. However, its safety and efficacy need to be verified in animal studies before clinical trials in patients can be conducted. This study evaluated the safety and efficacy of a PDO stent in normal and tracheomalacia model rabbits. Methods: In all, 29 New Zealand white rabbits were used, 13 for evaluating the biocompatibility of the PDO stent in normal rabbits and 16 for the creation of a tracheomalacia model. Of the 16, the tracheomalacia model was successfully established in 12 rabbits; PDO stents were placed in 8 of these rabbits.Results: The PDO stent was successfully positioned in the trachea of the normal rabbits using an endoscopic approach, and its degradation was observed 10 weeks later. The stent fragments did not induce distal airway obstruction or damage, and mucosal changes that occurred after stent placement were reversed after degradation. The same procedure was performed on the tracheomalacia model rabbits. The survival duration of the tracheomalacia rabbits with and without stents was 49.0

State of the Science in Tracheal Stents: A Scoping Review

“…Nineteen studies utilized different polymers as stent materials 15,46,47,51–66 . Only one of these represented a human clinical study where polydioxanone (PDS) stents were used in four patients 64 .…”

“…The majority of studies (26 of 35 preclinical studies) only evaluate biocompatibility and/or feasibility rather than treatment of an actual tracheal injury. A study by Choi et al combining a biocompatibility evaluation with a tracheal injury model and found that a bioabsorbable PDS stent remained in place for 10 weeks prior to degradation in the uninjured trachea but only remained 7 weeks in the injured one, illustrating that stent performance may vary across injury conditions 52 . Despite these facts, the available data trend toward improved efficacy of tracheal stenting employing polymers and drug‐eluting materials (which in this case were all polymer‐based).…”

“…A study by Choi et al combining a biocompatibility evaluation with a tracheal injury model and found that a bioabsorbable PDS stent remained in place for 10 weeks prior to degradation in the uninjured trachea but only remained 7 weeks in the injured one, illustrating that stent performance may vary across injury conditions. 52 Despite these facts, the available data trend toward improved efficacy of tracheal stenting employing polymers and drug-eluting materials (which in this case were all polymer-based). In addition, the sheer number of studies investigating tracheal stent design, specifically polymer and hybrid designs, has increased significantly over the last two decades.…”

“…Nineteen studies utilized different polymers as stent materials. 15,46,47,[51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66] Only one of these represented a human clinical study where polydioxanone (PDS) stents were used in four patients. 64 Specific materials include PDS (n = 5), polycaprolactone (n = 3), poly(lactic-co-glycolic acid) (n = 4), poly-L-lactic acid (n = 5), poly(L-lactideco-ε-caprolactone) (n = 1), polyisoprene (n = 1), poly-Llactide-caprolactone (n = 1), poly(D,L-lactide-co-ε-caprolactone)s [poly(DLLA-co-CL)s] (n = 1), and Poly(D,Llactide) (n = 1) (Tables I and IV).…”

Airway Stents from Now to the Future: A Narrative Review

“…Due to the irreversibility of stents and the difficulty of making matching deployment devices, surgery exposing the trachea is the most used insertion method. The total degradation of PLLA and PCL stents took almost 1 year, while the PLGA and PDO ones only took about 10 weeks [28, 30, 46, 47, 50]. The mechanical structure of biodegradable polymer stents could be divided into helical (spiral), tubular shape, tubular knitted, and mesh types.…”