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Biodegradable external tracheal stents and their use in a rabbit tracheal reconstruction model
T C Robey1, P M Eiselt, H S Murphy
1Department of Otolaryngology--Head and Neck Surgery, University of Michigan, Ann Arbor, USA.
Objectives/Hypothesis:
To design and develop an external biodegradable tracheal stent for use in airway reconstructive surgery.
Study Design:
Experimental model.
Methods:
Biodegradable external tracheal stents were fabricated from polyglycolic acid and poly(D,L-lactide-co-glycolide) (85:15). In vitro studies were performed to analyze the mechanical properties and degradative characteristics of these stents. Then the stents were tested in vivo in an anterior tracheal reconstruction model in New Zealand white rabbits.
Results:
The average dry modulus for the external stents was 1,800 kilopascal (kPa). All of the external stents cracked by 4 weeks in buffer solution. Significant mass loss was not appreciated until after 10 weeks in solution, but by 20 weeks the stents were nearly 100% degraded. In the in vivo portion of the study, the attrition rate for the control group was 23.1% versus 50% for the external stent group. The stridor rate was approximately 38% for both groups Of the rabbits that survived the entire 3 months of the study, the stented group, when measured by a balloon catheter method, had more patent airways than the control group, with an average stenosis of 27.8% versus 47.2%, respectively (P < .05). However, more accurate postmortem cast measurements of the internal airways did not confirm this.
Conclusions:
The external biodegradable tracheal stent employed in this study degraded in a predictable fashion and may provide a new method to augment surgical reconstruction of the anterior tracheal wall.