title: Reaction patterns of the tracheobronchial wall to implanted noncovered metal stents.
abstract: BACKGROUND
  Endoluminal implantation of stents has evolved as a nonsurgical treatment option for stenosis of the central airways. Based on the favorable results in treatment of tumorous tracheobronchial stenosis, stenting has been introduced into the therapy of nonmalignant stenosis.
  
  
  OBJECTIVE
  To study the long-term biocompatibility and incorporation of implanted bronchial stents based on the pathoanatomic reaction of the tracheobronchial system in humans. The incorporation of bronchial stents was documented, with specific interest in transformation or induction of dysplasia in the implantation zone.
  
  
  METHODS
  The tracheobronchial reaction was studied in 18 patients 2 days to 18 months after implantation of 24 noncovered metal stents (Wallstent; Schneider; Bülach, Switzerland; n = 8; and Ultraflex; Boston Scientific; Natick, MA; n = 16).
  
  
  RESULTS
  Stenting produced slow papillomatous growth of granulative tissue through the interfilamentary space of the stents. A nonspecific inflammatory response of nontumorous tissue could be documented. Sparse spots of superficial squamous cells occurred. No epithelial dysplasia or giant cells were detected within the stented region. The number of superficial ciliated cells in the implantation zone was markedly reduced.
  
  
  CONCLUSIONS
  After stent insertion in the upper airways, no malignant transformation of initially nontumorous tissue occurs. Stenting seems to be a safe therapy option when considered even for nonmalignant airway stenoses.
authors.affiliation: Institute of Pathology, University Hospital Bergmannsheil Bochum, Germany. PeterGrewe@AOL.com
authors.forename: Peter Hubert
authors.initials: PH
authors.lastname: Grewe
authors.forename: Klaus Michael
authors.initials: KM
authors.lastname: Müller
authors.forename: Michael
authors.initials: M
authors.lastname: Lindstaedt
authors.forename: Alfried
authors.initials: A
authors.lastname: Germing
authors.forename: Anette
authors.initials: A
authors.lastname: Müller
authors.forename: Andreas
authors.initials: A
authors.lastname: Mügge
authors.forename: Thomas
authors.initials: T
authors.lastname: Deneke
mesh_terms: D000328:Adult; D000368:Aged; D001980:Bronchi / Q000473:pathology*; D001999:Bronchoscopy; D004867:Equipment Design; D006801:Humans; D008670:Metals; D008875:Middle Aged; D015607:Stents; D014132:Trachea / Q000473:pathology*
chemical_list: D008670:Metals