title: Accurate localization of tissue layers in the esophagus by using a double-lumen injection catheter: implications for the Enteryx procedure.
abstract: BACKGROUND
  Enteryx (Boston Scientific Corp, Natick, Mass) is an injectable polymer used for the treatment of GERD. Current use of Enteryx requires fluoroscopy for accurate placement into the deep esophageal wall (ie, the deep submucosa or muscularis propria). In this study, we assessed the use of a new double-lumen, double-needle injection catheter for accurate placement of Enteryx into the deep esophageal wall, without fluoroscopy, in a porcine model.
  
  
  METHODS
  All procedures were performed by using a new injection catheter (GZ Medical, LLC, Minnetonka, Minn), which allows for tissue depth assessment via the flow of gas through one lumen and the injection of a therapeutic substance (Enteryx) via a second lumen. Endoscopy was performed on 5 consecutive pigs by using the new catheter alone, without fluoroscopy, and attempting deep injections. Four injections of Enteryx were made at the gastroesophageal junction, 10 cm above the junction, and 15 cm above the junction. A total of 60 sites (12 per animal) were injected. The animals were sacrificed and each esophagus was harvested. The mediastinal cavity was searched for extravasated Enteryx material, and the esophagus was examined grossly for Enteryx adherent to the outside wall. Injection sites then were classified morphologically as superficial (mucosa or submucosa), deep (muscularis propria or deep submucosa contiguous to muscularis), subadventitial (between muscle and adventitia), or transmural. Only deep injections were considered adequate.
  
  
  RESULTS
  No extravasated Enteryx was found in the mediastinum in 60 injected sites. One area of transmural injection had Enteryx adherent to the outside esophageal wall (1.7%). Fifty-one injected sites (85%) were adequate deep injections, 4 injections (6.7%) were subadventitial, 1 injection (1.7%) was superficial, and 3 injections (5%) could not be assessed. There were no complications observed in any animal.
  
  
  CONCLUSIONS
  By using a new injection device without fluoroscopy, Enteryx can be deposited consistently into the deep esophageal wall with a high degree of accuracy, avoiding mediastinal extravasation. Additional clinical trials are necessary to determine the relative accuracy and role of the new technique compared to standard radiographically guided placement.
authors.affiliation: Department of Gastroenterology, Abbott-Northwestern Hospital, Minneapolis, Minnesota, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Ganz
authors.forename: Mark
authors.initials: M
authors.lastname: Rydell
authors.forename: Paul
authors.initials: P
authors.lastname: Termin
mesh_terms: D000818:Animals; D002245:Carbon Dioxide; D002404:Catheterization / Q000295:instrumentation*; D004867:Equipment Design; D004945:Esophagoscopy; D004947:Esophagus; D005240:Feasibility Studies; D007267:Injections / Q000295:instrumentation; D011145:Polyvinyls / Q000008:administration & dosage*; D013552:Swine
chemical_list: D011145:Polyvinyls; D002245:Carbon Dioxide; C020320:ethylene-vinyl alcohol copolymer