A number of benign and malignant disorders of the upper airways can cause tracheobronchial narrowing, stricture, compression, or collapse (i.e., tracheobronchial malacia), ultimately leading to symptomatic and potentially life-threatening dyspnea. These tracheobronchial compromises can be managed with endobronchial dilation in addition to placement of endotracheal, bronchial, or tracheobronchial stents. Generally, stent placement can be accomplished safely and provides immediate relief of symptoms in the acute setting. Over the long term, stent placement has been shown to improve the patient's quality of life. The use of endobronchial stents has accelerated recently as a result of the proliferation of new biocompatible materials, novel stent designs, and easier techniques for deployment.
Although stents have been described in reports dating back to the 1800s, the concept of using stents to relieve acute tracheobronchial obstruction was not reported until the mid-1950s.1 Dumon2 designed a dedicated endoluminal upper airway stent in the late 1990s, and it remains today one of the most commonly used silicone stents. The self-expanding metal stents manufactured from biocompatible metal alloys also were pioneered in the 1990s using technology initially developed for vascular and coronary stents.3,4 The ideal tracheobronchial stent has yet to be perfected, and there are potentially life-threatening risks associated with all stents currently on the market. Making the correct stent selection therefore is critical for the well-being of the patient.
Indications for Endobronchial Stents
The indications for deployment of airway stents include (1) extrinsic compression of the central airways with or without intraluminal components owing to malignant or benign disorders; (2) complex, inoperable tracheobronchial strictures; (3) tracheobronchial malacia; (4) palliation for recurrent intraluminal tumor growth; and (5) central airway fistulas (i.e., esophagus, mediastinum, or pleura).
Presenting signs and findings may include dyspnea, cough, hemoptysis, recurrent lung infections, wheezing, and stridor. On occasion, a patient may be referred for evaluation of findings made on a screening CT scan. Since many types of endobronchial therapies are available for patients with airway disorders, it is important to recognize that stenting is just one such modality and the patient may benefit from a combination of treatments.
Desirable Stent Characteristics
The ideal stent should be easy to insert and remove yet resistant to migration. It should be sufficiently strong to support the airway yet flexible enough to withstand (and collapse with) cough without fracturing, narrowing, or moving. The material from which the stent is made should be biologically inert to minimize the formation of granulation tissues. The stent should not change in size when collapsed, or a scar may form at its two ends. The stent should be available in a variety of lengths and sizes, and its walls should be as thin as possible for a maximal intraluminal diameter to prevent retention of secretions. The stent should permit movement of secretions across its surface to prevent inspissation ...