Current concepts in severe adult tracheobronchomalacia: evaluation and treatment

Abstract

There is increasing recognition of tracheobronchomalacia (TBM) in patients with respiratory complaints, though its true incidence in the adult population remains unknown. Most of these patients have an acquired form of severe diffuse TBM of unclear etiology. The mainstays of diagnosis are dynamic (inspiratory and expiratory) airway computed tomography (CT) scan and dynamic flexible bronchoscopy with forced expiratory maneuvers. While the prevailing definition of TBM is 50% reduction in cross-sectional area, a high proportion of healthy volunteers meet this threshold, thus this threshold fails to identify patients that might benefit from intervention. Therefore, we consider complete or near-complete collapse (>90% reduction in cross-sectional area) of the airway to be severe enough to warrant potential intervention. Surgical central airway stabilization by posterior mesh splinting (tracheobronchoplasty) effectively corrects malacic airways and has been shown to lead to significant improvement in symptoms, health-related quality of life, as well as functional and exercise capacity in carefully selected adults with severe diffuse TBM. A short-term stent trial clarifies a patient's candidacy for surgical intervention. Coordination of care between experienced interventional pulmonologists, radiologists, and thoracic surgeons is essential for optimal outcomes.

Keywords: Expiratory central airway collapse (ECAC); severe diffuse tracheobronchomalacia (TBM); tracheobronchoplasty (TBP).

Figure 1

Schematic representation of (A) normal airway and (B) malacic airway pathology. Representative cross section images obtained during dynamic computed tomography (CT) scan and dynamic bronchoscopy accompany the airway diagrams.

Figure 2

Beth Israel Deaconess Medical Center (BIDMC) Institutional protocol for evaluation of patients with severe diffuse tracheobronchomalacia (TBM).

Figure 3

Schematic of expiratory central airway collapse (ECAC). (A) Top: airway represents the form of tracheobronchomalacia (TBM) characterized by weakness that affects primarily the anterior tracheobronchial wall. A representative cross sectional CT image accompanies the diagram. Bottom: diagram represents the form of TBM characterized by invagination of the atrophic posterior membrane into airway lumen. A representative cross sectional computed tomography (CT) image accompanies the diagram; (B) tracheobronchoplasty. Suture is seen passed in a partial thickness mattress fashion through the airway wall. Typically, the entire thoracic trachea is splinted, then the right mainstem and bronchus intermedius, and then left mainstem bronchus [Reprinted with permission (28)].