Complications involving the mediastinum after injection of Enteryx for GERD

Abstract

The Food and Drug Administration approved the use of Enteryx (Microvasive Endoscopy, Boston Scientific Corp, Natick, Mass) for the treatment of GERD in April 2003. Enteryx is a biocompatible polymer that is injected intramuscularly into the lower esophageal sphincter (LES). The injections are made under fluoroscopy to ensure correct placement of the substance and to avoid inadvertent submucosal or transmural injection. The injection solution contains ethylene vinyl alcohol, which is dissolved in dimethyl sulfoxide (DMSO) and is mixed with tantalum, a radiopaque contrast agent. After injection into tissue, the DMSO rapidly dissipates by diffusion and the polymer precipitates as a spongy material. The latter initiates an acute and, eventually, chronic inflammatory response, leading to fibrous encapsulation of the polymer. Preliminary studies have shown Enteryx to be efficacious for control of symptoms and allows discontinuation of pharmacotherapy for GERD. The most common complication with Enteryx injection is chest pain, which occurs in over 90% of patients and usually is mild. Dysphagia also is fairly common, occurring in approximately 20% of patients, but this usually is of short duration and does not require therapy. To date, a major complication of Enteryx injection has not been reported. However, reported here are two cases of serious complications involving the mediastinum after Enteryx injection for GERD.