Rafanan A L, Mehta A C
Department of Pulmonary and Critical Care Medicine, Cleveland Clinic Foundation, Ohio 44195, USA.
Radiol Clin North Am. 2000 Mar;38(2):395-408. doi: 10.1016/s0033-8389(05)70170-6.
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.
支气管内阻塞的内镜治疗正变得越来越重要。气管支气管支架在治疗黏膜下或支气管外病变引起的阻塞时常常是必需的。自20世纪60年代初以来就有管形支架，但由于其插入需要使用硬支气管镜，所以使用不足。随着金属支架的近期发展，介入放射科医生越来越多地参与气管支气管阻塞的治疗。金属支架借助可弯曲支气管镜易于放置，越来越受欢迎。在各种临床系列研究中已表明，所有可用的气管支气管支架都能够使各种气管支气管阻塞引起的呼吸道症状立即得到缓解。然而，支架的性能不应仅基于短期反应来判断。目前，尚无理想的支架，因为没有一种支架能免于并发症，也没有一种能始终保持终身通畅。朱安图科支架会引发严重的主要并发症（支气管穿孔和支架支柱骨折），不再推荐用于气管支气管树。帕尔马兹支架也已失宠，因为诸如剧烈咳嗽等强大外力可使其再次受压。施特雷克尔支架仅可用于较小气道，但对于短节段狭窄的精确支架置入可能有用，因为它在展开时不会缩短。华尔支架和超弹性支架是我们目前选择的金属支架。两者都易于展开，有带覆膜的形式，能施加足够的径向力，位置相对稳定，并且具有良好的纵向柔韧性，可用于迂曲的气道。缺点包括肉芽组织过度形成以及支架上皮化后难以取出。对于有持续活动性局部炎症的良性病变或需要临时支架置入时，应非常谨慎地选择金属支架。在没有理想支架的情况下，技术进步将继续。潜在的发展包括可取出的金属支架、可生物降解的支架以及化学和放射性涂层支架。毫无疑问，不断扩大的支架市场将推动科研朝着理想支架的开发发展。显然，医生需要随时准备评估这些技术进步。
