title: A new design of the esophageal Wallstent endoprosthesis resistant to distal migration.
abstract: OBJECTIVE
  Because plastic-covered metallic stents used in the palliation of patients with unresectable esophageal cancer are associated with significant rates of migration, particularly when the lower end of the stent projects into the gastric fundus, the purpose of this study was to establish whether two new prototype designs of the Wallstent esophageal endoprosthesis are prone to migration.
  
  
  METHODS
  A cylindrical stent and a conical stent were studied. Both designs included plastic covering inside the metallic mesh. In addition, the conical device incorporated a variation in the braiding angle between the upper and lower parts of the endoprosthesis. Ten conical stents and eight cylindrical stents were inserted in 18 patients with tumors involving the gastroesophageal junction who were followed up with esophagography and endoscopy.
  
  
  RESULTS
  All insertions of stents were successful. Two cylindrical stents (25%) migrated distally. Two conical stents (20%) migrated proximally. One perforation occurred that was associated with distal migration of a cylindrical stent.
  
  
  CONCLUSIONS
  The frequency of distal migration of cylindrical stents is unacceptably high. Conical stents are resistant to distal migration, although improvements in design are required to deal with the problem of proximal migration.
authors.affiliation: Department of Radiology, Guy's Hospital, London, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Adam
authors.forename: R
authors.initials: R
authors.lastname: Morgan
authors.forename: J
authors.initials: J
authors.lastname: Ellul
authors.forename: R C
authors.initials: RC
authors.lastname: Mason
mesh_terms: D000230:Adenocarcinoma / Q000150:complications*; D000368:Aged; D000369:Aged, 80 and over; D003680:Deglutition Disorders / Q000628:therapy*; D004938:Esophageal Neoplasms / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010166:Palliative Care; D011474:Prosthesis Design; D011475:Prosthesis Failure; D015607:Stents