Early Surgical Management of Thermal Airway Injury: A Case Series

Abstract

Inhalation injury is an independent risk factor in burn mortality, imparting a 20% increased risk of death. Yet there is little information on the natural history, functional outcome, or pathophysiology of thermal injury to the laryngotracheal complex, limiting treatment progress. This paper demonstrates a case series (n = 3) of significant thermal airway injuries. In all cases, the initial injury was far exceeded by the subsequent immune response and aggressive fibroinflammatory healing. Serial examination demonstrated progressive epithelial injury, mucosal inflammation, airway remodeling, and luminal compromise. Histologic findings in the first case demonstrate an early IL-17A response in the human airway following thermal injury. This is the first report implicating IL-17A in the airway mucosal immune response to thermal injury. Their second and third patients received Azithromycin targeting IL-17A and showed clinical responses. The third patient also presented with exposed tracheal cartilage and underwent mucosal reconstitution via split-thickness skin graft over an endoluminal stent in conjunction with tracheostomy. This was associated with rapid abatement of mucosal inflammation, resolution of granulation tissue, and return of laryngeal function. Patients who present with thermal inhalation injury should receive a thorough multidisciplinary airway evaluation, including early otolaryngologic evaluation. New early endoscopic approaches (scar lysis and mucosal reconstitution with autologous grafting over an endoluminal stent), when combined with targeted medical therapy aimed at components of mucosal airway inflammation (local corticosteroids and systemic Azithromycin targeting IL-17A), may have potential to limit chronic cicatricial complications.

Figure 1.

(A) Postinjury day 5. Direct laryngoscopy from postinjury day 5 revealed diffuse mucosal sloughing throughout the hypopharynx, supraglottis, glottis, subglottis, and proximal trachea. The carina, bilateral mainstem bronchi showed preserved mucosal integrity with diffuse erythema. Notably, the oral cavity and the majority of the oropharynx were spared. (B) Postinjury day 10. Direct laryngoscopy from postinjury day 5 reveals similar diffuse mucosal sloughing at the level of the glottis and trachea; however, mucosal injury has progressed to the carina and bilateral mainstem bronchi. (C) Postinjury month 6. Direct laryngoscopy 6 months postinjury. Exam revealed bilaterally fixed vocal folds, cicatricial scarring at bronchial mainstem, and significant restrictive lung disease on Pulmonary Function Testing (PFTs preformed via open tracheostomy). (D) Postinjury day 10 immunohistochemistry. Immunohistochemistry from biopsies of the glottis and right mainstem bronchus (MSB) taken on postinjury day 15 demonstrate abundant subepithelial IL-17A protein.

Figure 2.

(A) Postinjury day 6. Direct laryngoscopy showed significant thermal injury to his glottis and immediate subglottis with anthracotic debris, as well as glottic level edema obstructing the laryngeal inlet. Bilateral palpation of the CAJ demonstrated good mobility. (B) Postinjury day 17. Repeat operative endoscopy day showed healing anterior laryngeal mucosa. Yet the posterior glottis showed mild webbing with pronounced granulation tissue. (C) Postinjury month 2. When seen in clinic 44 days postburn, his larynx had regained limited abduction (primarily driven by left TVF mobility gains).

Figure 3.

(A) Postinjury day 24. Direct larygoscopy revealed and a 5-mm glottic gap secondary to abundant vocal process granulation tissue, which underwent cold debridement and corticosteroid injection into the bilateral CAJ. Subglottic granulation tissue was also visualized. (B) Postinjury day 31. A split-thickness skin graft secured over an adaptic-covered suprastomal stent (distal limb of a 12-mm Montgomery T-tube) was placed endoscopically. The stent was secured externally and the indwelling #6 proximal XLT Shiley tracheotomy was maintained. The suprastomal stent was removed 2 weeks later in the OR; endoscopy at that time showed improved mucosal coverage above the tracheostomy stoma and healing mucosa in the larynx. (C) Postinjury month 3. Clinical exam with fibreoptic endoscopy showed return of laryngeal function.