Treatment of adult tracheobronchomalacia and excessive dynamic airway collapse : an update.

Tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC) are both dynamic forms of central airway obstruction characterized by a decrease of >/=50% in the cross-sectional area of the tracheobronchial lumen. The differences between these two entities, however, are not uniformly accepted in the medical community. While TBM is characterized by a weakness of the tracheobronchial cartilaginous structures, EDAC is marked by excessive bulging of the posterior membrane into the airway lumen during exhalation. These disease entities are probably underdiagnosed because they present with a variety of nonspecific symptoms similar to patients with other obstructive ventilatory disorders such as asthma and COPD. Diagnosis is confirmed by dynamic radiologic imaging studies or bronchoscopy. Current therapeutic management depends on the extent, type, and severity of airway abnormalities noted and the clinical presentation. Proposed management alternatives include conservative medical therapy, and minimally invasive and open surgical interventions. Inhaled bronchodilators should be used only if symptoms and ventilatory function improve after use. Continuous positive airway pressure acts as a pneumatic stent and should be considered as an alternative or additional therapeutic modality. Endoluminal stent insertion can improve symptoms and pulmonary function in patients with central airway obstruction and should be considered for patients with symptoms refractory to conservative therapy. Several open surgical procedures have also been performed over the years, including tracheostomy, airway splinting, tracheal resection and, more recently, external tracheal stents. Endobronchial laser therapy, resorbable stents, application of grafting materials used to support the collapsed airway as well as the use of cartilage regeneration techniques are experimental, and their efficacy in humans remains to be determined. Future studies should compare therapeutic interventions and outcomes such as functional status, ventilatory function, and bronchoscopic and radiologic appearances in order to define the costs and benefits of individual and combined treatment modalities.