Microbial Diversity and Biofilm Presence on Pediatric Airway Stents

Introduction: Airway stents are often used in double-staged laryngotracheoplasty (dsLTP) procedures to provide support for cartilage graft healing. Biofilm is suspected to develop on these stents but its microbial composition has not been well-described. The aim of this study is to characterize the bacterial diversity and biofilm on airway stents and its association with granulation tissue formation or restenosis in pediatric patients.

Methods: This is a prospective observational study of 20 pediatric patients who underwent dsLTP or cricotracheal resection with cartilage grafting and airway stent placement from August 2019 to August 2020. The stents were collected at time of removal and bacterial colonization was evaluated using cultures and shotgun metagenomic sequencing. Operative videos and notes from stent removal and subsequent microlaryngoscopy and bronchoscopy (MLB) were reviewed for presence of post-operative complications (granulation tissue, early restenosis, graft failure, and dehiscence).

Results: Of the 20 patients, 8 (40%) were male and mean age was 3.86 (range of 0.96 – 12.5) years. Airway stents were in place for a mean of 50 days. Eight patients (40%) developed early restenosis, 17 (85%) had granulation tissue at time of stent removal and 14 (35%) had granulation tissue at time of first MLB after stent removal. The Shannon diversity index (SDI) on metagenomic sequencing was not significantly different in patients who had granulation tissue formation versus those who did not on first MLB after stent removal (2.55 versus 2.45, p-value = 0.29). The SDI in patients who developed restenosis was higher than in patients who did not restenose (2.80 versus 2.25, p-value 0.055) but did not reach statistical significance.

Conclusions: This is the first pilot study examining the pediatric airway microbiome after airway reconstruction. Microbiome composition correlated to culture results but were not significantly different in patients who developed restenosis or granulation tissue versus those who did not.