Mechanical effect of the Angelchik prosthesis on the competency of the gastric cardia: pathophysiologic implications and surgical perspectives

Abstract

The Angelchik prosthesis appears to be effective in preventing gastroesophageal reflux, although its precise mechanism of action remains controversial. In a unique in vitro model, 10 freshly harvested canine esophagogastric specimens were tested for their ability to remain competent against challenges of intragastric pressure under controlled conditions of intra-abdominal pressure, longitudinal esophageal tension, lower esophageal sphincter pressure and overall length and circumference of the cardia (measure of gastric dilatation). Competency of the specimen was assessed by stepwise variation in the overall length of the sphincter, while keeping constant intraabdominal pressure (20 cm H2O), intragastric pressure (20 cm H2O), esophageal tension (physiologic), lower esophageal sphincter pressure (15 cm H2O) and degree of gastric dilatation (3 cm). With each specimen serving as its own control, the effect produced by the application of an Angelchik prosthesis was evaluated. Results consistently demonstrated that at any lower esophageal sphincter length the percent of competency was increased when the prosthesis was applied (P < 0.01). The findings indicate that the Angelchik prosthesis controls reflux by preventing unfolding of the lower esophageal sphincter when challenged by intragastric pressure.

Magnetic Augmentation of the Lower Esophageal Sphincter: Results of a Feasibility Clinical Trial

“…In other words, the magnetic force of the MSA device, which is highest when the device is closed, prevents the LES shortening induced by gastric distension. 18,19 Interestingly, all patients queried in this series were able to belch after surgery. As expected, postoperative manometric values at rest did not change compared to preoperative findings.…”

Laparoscopic Sphincter Augmentation Device Eliminates Reflux Symptoms and Normalizes Esophageal Acid Exposure

“…The precise sizing of the device with the beads approximated to match the outer diameter of the resting GEJ prevents compression of the esophagus while increasing its resistance to opening by gastric distension or pressure. [16][17][18] This concept is supported by the observation that the device did not significantly alter the resting LES pressure in those patients who had a normal LES pressure before surgery.…”

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

“…The theoretical mechanism is common to all the proposed techniques and involves prevention of the unfolding of the sphincter in response to gastric distension. The well-established ecacy of the Angelchik prosthesis [1,2] provides proof of principle, although erosion of this extraluminal foreign body and the high prevalence of dysphagia prevents its clinical use. Present techniques include valvuloplasty via endoluminal suture placement [6], controlled scarring of the cardia via radiofrequency energy delivery [19], and perhaps most promising, lower esophageal sphincter augmentation (LESA) via intramural injection of a biocompatible polymer.…”