Lower esophageal sphincter injection of a biocompatible polymer: accuracy of implantation assessed by esophagectomy.

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.

Endoscopic augmentation of the cardia with a biocompatible injectable polymer (Enteryx) in a porcine model.

BACKGROUND: Endoscopic approaches to restore the gastroesophageal barrier in patients with gastroesophageal reflux disease (GERD) are presently undergoing clinical trial. The aim of the study was to demonstrate the feasibility, durability, safety, and antireflux efficacy following augmentation of the cardia with a biocompatible injectable polymer (Enteryx). METHODS: Augmentation was performed in 12 Yucatan mini-pigs. The cardia was injected circumferentially with 1-1.5 ml of Enteryx at three or four sites. Four groups of three animals each were killed at 2, 6, 12, and 24 weeks following augmentation. Gastrointestinal endoscopy and esophageal manometry were performed preoperatively and postoperatively. Competency was determined as the intragastric pressure (yield pressure) and volume (yield volume) needed during gastric distension with air and water to result in equalization of gastric and esophageal pressure. Comparisons were made with a group of noninjected animals (n = 6). RESULTS: All animals had a normal eating pattern; none showed any evidence of vomiting or regurgitation. The median injection volume was 4 ml (range, 1-8). At autopsy, implants were found in 83% of the animals. Intramuscular placement of the implant was durable, whereas sloughing occurred if the implant was placed submucosally. The mechanical properties of sphincter length and pressure were unaffected by the injection. The median yield pressure of the animals that survived for >6 weeks (21.4 mmHg) was significantly greater (p = 0.049) than the animals that survived for <6 weeks (4.5 mmHg) and greater (p = 0.054) than the control animals (9.1 mmHg), suggesting that the healing process was associated with reduced distensibility of the cardia. CONCLUSIONS: Augmentation of the cardia with an injectable polymer (Enteryx) is simple, safe, and durable. Early studies suggest that alteration in the distensibility and geometry of the gastroesophageal junction may provide antireflux protection.