Stenting of the tracheobronchial tree.

Endoscopic treatment of endobronchial obstructions is becoming increasingly important. Tracheobronchial stents often are needed in the treatment of obstructions from submucosal or extrabronchial lesions. Tube stents have been available since the early 1960s but are underused because their insertion requires the use of a rigid bronchoscope. With the recent development of metallic stents, interventional radiologists increasingly are involved in the treatment of tracheobronchial obstructions. Metallic stents, easily placed with flexible bronchoscopy, are growing in popularity. All available tracheobronchial stents have been shown in various clinical series to be able to achieve immediate resolution of respiratory symptoms from various tracheobronchial obstructions. A stent's performance, however, should not be based solely on short-term response. Presently, there is no ideal stent because none is free of complications and none are able to consistently maintain life-long patency. Gianturco stents are associated with serious major complications (bronchial perforations and strut fractures) and are no longer recommended for use in the tracheobronchial tree. The Palmaz stent has also fallen into disfavor, because a strong external force, such as a vigorous cough, can recompress it. The Strecker stent can only be used in smaller airways, but may be useful in the accurate stenting of short segment stenoses because it does not foreshorten on deployment. The Wallstent and Ultraflex are our present metallic stents of choice. Both are easy to deploy, available in covered forms, exert adequate radial force, remain relatively stable in position, and have good longitudinal flexibility for use in tortuous airways. Disadvantages include excessive granulation tissue formation and difficulty of removal once the stent has been epithelialized. Metallic stents should be chosen very carefully for use in benign lesions with ongoing active local inflammation or when temporary stenting is needed. In the absence of an ideal stent, technologic advancements will continue. Potential developments include removable metallic stents, biodegradable stents, and chemically and radioactively coated stents. Unquestionably, the expanding stent market will drive scientific research toward the development of the ideal stent. Clearly, physicians need to be ready to assess these technologic advancements.