Eur J Cardiothorac Surg 2006;30:682
© 2006 Elsevier Science NL
Editorial comment
Lateral window in self-expanding metal stents
Federico Venuta*
Department of Thoracic Surgery, Rome Policlinico Umberto I, University of Rome, Rome 00100, Italy
* Tel.: +39 06 4461971; fax: +39 06 4463667. (Email: sofed{at}libero.it).
Since the beginning of the ‘new era’ in lung transplantation [1] in the early 80s, advances in surgical technique and immunosuppression have progressively led to improved survival and decreased postoperative complications. However, bronchial complications still remain a potential source of morbidity; they may arise at any level, from the anastomosis to more distal bronchial districts, involving also lobar orifices and bronchi; treatment of this complication is often challenging, requiring the ability of the pulmonologist, the endoscopist, and the thoracic surgeon. In fact, they may require multiple and complex endobronchial treatments, and in some cases also resection of the involved bronchial segment may be necessary. Granulation, fibrosis, dehiscence and malacia, alone or in association, may be treated with laser, mechanical dilation, cryoablation; however, at the end of each procedure, stent placement should always be considered if the airway needs to be protected and stabilized from the inside.
In the early days silicone stents were developed and became extremely popular; they certainly contributed to solve many difficult situations [2]. They were easy to place and not expensive but had a number of drawbacks: rigidity and thickness of the wall, incrustation of bronchial secretions, granulations at each end, and need of the rigid bronchoscope and deep sedation to be placed; however, they had the advantage of being easily removed and replaced when required.
As last generation self-expandable metallic stents (covered and uncovered) become available, they have progressively gained popularity. They can be easily deployed through the flexible fiberoptic bronchoscope and can adapt also to tortuous and tight bronchial strictures. Probably airway problems following lung transplantation offer the best indication for these stents. However, the relative ease of placement have certainly encouraged an immoderate use of them and we should not forget that important complications are associated also to placement of these devices, in particular granulation that may appear in up to 30% of the patients [3]; they are also more expensive than the silicone one, but their elevated costs are justified in difficult anatomical setting.
A long stenosis crossing and including a bronchial orifice, like the right upper lobe one, is not rare after lung transplantation and may be difficult to treat. The etiology of this complication is probably related to several factors like ischemia and devascularization, acute and chronic rejection, infection; after dilation, stenting is often required to achieve airway stability, but covering and limiting ventilation of the bronchial orifice should be avoided since it may cause infection, especially in the immunocompromised patient. Peled et al. [4] report their experience with the use of expandable metallic stents in this difficult situation; in this setting, previous reports have advocated surgical treatment, including a bronchial sleeve resection, a lobectomy or bilobectomy, and retransplantation [5]. Self-expandable metallic stents can be placed across the bronchial orifice, opening a lateral window to facilitate ventilation and clearance of secretions from the lung parenchyma. The authors should be commended for rescuing a trick that has been described several years ago both for Wallstents and Schneider stents [6,7], and should certainly be known and considered when facing these difficult airway problems. The lateral window can be opened immediately after stent placement or a couple of weeks later, when the strut of the stent is well adherent to the bronchial wall and dislocation during the endoscopic maneuvers is more difficult. There are two different techniques to open a window in the mesh; it can be done with Nd:Yag laser or by balloon dilatation under fluoroscopic guidance; both methods have been successful. If the latter method is to be employed a guide wire should be passed through the stent mesh that is subsequently dilated by inserting sequentially larger balloons until a lumen is achieved that roughly approximates the size of the lobar bronchus (7 mm). The few cases reported in the literature are not associated with complications and long-term follow-up confirms patency and absence of granulation. As mentioned by Peled et al. there are new silicon stents with a protrusion lateral branch that may be considered as a feasible option.
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