Ann Thorac Surg 2003;75:324
© 2003 The Society of Thoracic Surgeons
Correspondence
Ultraflex expandable metallic stents: difficulties in benign tracheal stenoses
Bernd Schmidt, MDa,
Christian Witt, MDa
a Division of Pneumology, Department of Internal Medicine I, Medical School (Charité) of Humboldt University of Berlin, Charité Campus Mitte, Schumannstr 20/21, D-10098 Berlin, Germany
e-mail: b.schmidt{at}charite.de
To the Editor:
We read with great interest the article by Madden and coworkers regarding their experiences with Ultraflex Metallic stents [1]. We agree with their encouraging experiences concerning immediate effects and regarding tumorous stenoses. Concerning the treatment of benign tracheal stenoses, we feel obliged to report long-term difficulties with metallic stents that are of some importance. Like Madden and associates, we implanted covered Ultraflex-Stents in several nontumorous tracheal stenoses. In three cases, penetration of granulation tissue through the open stent meshes at both ends of the stent caused serious problems. These granulations appeared 4 to 8 months after stent implantation. Patient 1 required recurrent interventions for removal of granulations. Furthermore, after 18 months, the stent wire fractured due to persistent cough (Fig 1).
Patient 2 suffered from retention of secretions within the stent when granulations at the proximal end led to substantial restenosis (Fig 2).
These problems could not be solved interventionally, and the patient died 1 year after stenting from recurrent pneumonia. Patient 3, who presented with important granulations and a circular scar at the proximal end, required stent removal after 4 months. This was extremely difficult. The stent had to be fragmented in order to remove the ingrown parts of it. The procedure caused extensive lesions of the tracheal wall, and the airway lumen was finally restored with a silicone stent.
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Fig 1. Penetration of granulations at the distal uncovered end and stent fracture (arrows) due to persistent cough (18 months in place).
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These anecdotal reports show two problems. First, once granulations appear through the stent, they are extremely difficult to remove with lasting effect. A Nd:YAG laser cannot be used because, even at a low power, stents can be destroyed. In an experimental study, we showed that metallic stents are destroyed by laser (10 W) when the distance between the quartz fiber and the stent is 2 mm [2]. Second, removal of metallic stents can be very difficult in benign conditions.
Considering the fact that benign tracheal stenoses may accompany our patients’ lives for many years, we prefer another strategy. These stenoses are treated with silicone stents that can be removed after a certain interval when the tracheal wall stiffens around the stent after inflammation subsides, or when difficulties (granulations, severe secrete retention) appear [3].
References
- Madden B.P., Datta S., Charokopos N. Experience with Ultraflex expandable metallic stents in the management of endobronchial pathology. Ann Thorac Surg 2002;73:938-944.[Abstract/Free Full Text]
- Witt C., Schmidt B., Liebetruth J., Baumann G. Nd:YAG laser and tracheobronchial metallic stents: an experimental study. Lasers Surg Med 1997;20:51-55.[Medline]
- Schmidt B., Olze H., Borges A.C., et al. Endotracheal balloon dilatation and stent implantation in benign stenoses. Ann Thorac Surg 2001;71:1630-1634.[Abstract/Free Full Text]
