title: Lower esophageal sphincter injection of a biocompatible polymer: accuracy of implantation assessed by esophagectomy.
abstract: BACKGROUND
  Endoscopic lower esophageal sphincter (LES) implantation of a biocompatible polymer is undergoing clinical trial as an alternative to pharmacologic and laparoscopic treatments for gastroesophageal reflux disease. The safety and efficacy of LES augmentation depend on accurate placement of the implant into the wall of the esophagus. To date, no study has demonstrated the prevalence and location of the intended implant.
  
  
  METHODS
  The study group consisted of nine patients with underlying esophageal disease severe enough to warrant esophagectomy. Three or four implants of 1 or 2 cc of Enteryx (a biocompatible ethylene-vinyl alcohol copolymer dissolved in dimethyl sulfoxide with micronized tantalum as a radiopaque marker) were placed at the squamocolumnar junction of each patient via a 4-mm, 23-gauge needle under endoscopic guidance. Fluoroscopy was utilized in all patients to facilitate endoscopic placement. Outcome measures included the prevalence and location of successful implantation into the wall of the esophagus.
  
  
  RESULTS
  Thirty of 34 implants (88%) were successfully placed into the wall of the esophagus. The remaining 4 were found lying subserosally or attached to the exterior of the gastroesophageal junction (GEJ). Fluoroscopically, the implants often tended to coalesce, forming arcs or a ring around the GEJ. Histologic examination revealed implantation into the deep submucosa contiguous with the circular muscle and within the muscularis propria in all patients, with implants occasionally extending into the subserosa. There were no untoward reactions identified.
  
  
  CONCLUSIONS
  Endoscopically directed implantation of a biocompatible polymer into the esophageal wall can be accomplished with a high degree of accuracy. Injection via a 4-mm needle results in the placement of material along and within the muscular layers of the esophagus.
authors.affiliation: University of Southern California, 1510 San Pablo Street, Los Angeles, CA 90033, USA. jhpeters@surgery.usc.edu
authors.forename: J H
authors.initials: JH
authors.lastname: Peters
authors.forename: D E
authors.initials: DE
authors.lastname: Silverman
authors.forename: A
authors.initials: A
authors.lastname: Stein
mesh_terms: D001672:Biocompatible Materials / Q000008:administration & dosage*; D004724:Endoscopy; D016629:Esophagectomy; D004943:Esophagogastric Junction / Q000473:pathology*; D005471:Fluoroscopy; D005764:Gastroesophageal Reflux / Q000628:therapy*; D006801:Humans; D007267:Injections; D011145:Polyvinyls / Q000008:administration & dosage*; D019736:Prostheses and Implants; D019919:Prosthesis Implantation / Q000379:methods*
chemical_list: D001672:Biocompatible Materials; D011145:Polyvinyls; C020320:ethylene-vinyl alcohol copolymer