title: Elastic deformation properties of implanted endobronchial wire stents in benign and malignant bronchial disease: A radiographic in vivo evaluation.
abstract: OBJECTIVE
  To evaluate the long-term mechanical behavior in vivo of expandable endobronchial wire stents, we imaged three different prostheses in the treatment of tracheobronchial disease.
  
  
  METHODS
  Six patients with bronchial stenoses (three benign, three malignant) underwent insertion of metallic stents. Two self-expandable Wallstents, two balloon-expandable tantalum Strecker stents and two self-expandable nitinol Accuflex stents were used. Measurements of deformation properties were performed during voluntary cough by means of fluoroscopy, at 1 month and 7-10 months after implantation. The procedures were videotaped, their images digitized and the narrowing of stent diameters calculated at intervals of 20 msec.
  
  
  RESULTS
  After stent implantation all patients improved with respect to ventilatory function. Radial stent narrowing during cough reached 53% (Wallstent), 59% (tantalum Strecker stent), and 52% (nitinol Accuflex stent) of the relaxed post-implantation diameter. Stent compression was more marked in benign compared with malignant stenoses. In the long term permanent deformation occurred with the tantalum Strecker stents; the other stents were unchanged.
  
  
  CONCLUSIONS
  Endobronchial wire stents can be helpful in the treatment of major airway collapse and obstructing bronchial lesions. However, evidence of material fatigue as a possible effect of exposure to recurrent mechanical stress on the flexible mesh tube may limit their long-term use. This seems to be predominantly important in benign bronchial collapse.
authors: Medizinische Klinik, Klinikum Innenstadt, Ludwig-Maximilians-University, Ziemssentrasse 1, D-80336 Munich, Germany.
authors: H
authors: H
authors: Hautmann
authors: J
authors: J
authors: Rieger
authors: R M
authors: RM
authors: Huber
authors: K J
authors: KJ
authors: Pfeifer
mesh_terms: D000402:Airway Obstruction / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy*; D001982:Bronchial Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*; D001984:Bronchial Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy; D002294:Carcinoma, Squamous Cell / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy; D004548:Elasticity; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005471:Fluoroscopy; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015607:Stents; D016896:Treatment Outcome