Wide Endoscopic Mucosal Resection in Esophagus Using Modified Needle Knife: Porcine Model Experiment

Abstract

Purpose: Endoscopic mucosal resections are increasingly being applied for diagnosis and treatment of esophageal lesions including malignancies and Barrett's high-grade dysplasia. One of the limitations of the current techniques is the size of the resection due to the accessory dimension. In this study, we investigated the feasibility and safety of wide mucosal resection in esophagus using a modified needle knife in porcine model. Methods: Four pigs (30∼50kg) were used after institutional animal protocol approval. Under general anesthesia, upper endoscope (either GIF-Q160 or GIF-2T160) was advanced orally to distal esophagus. Sterile saline with 1:100,000 to 1:200,000 epinephrine (+ India ink) was injected submucosally (20∼60cc total). After initial marking with a needle knife, horizontal mucosal incision at the distal and proximal levels of rectangular region in distal esophagus was performed using an insulated-tip modified needle knife (IT-knife, Olympus/Olympus America) at 40W cut current with Blend 1 (Valleylab). This was followed by longitudinal mucosal incision at the lateral borders. Using ample saline injections, submucosal incision with the IT-knife was continued. The residual adherence at the end was disrupted with polypectomy snare in standard fashion. Simple coagulation techniques were applied for local bleeding control if needed. Post-procedurally, lansoprazol 60 mg was given orally. The pigs were fed soft diet and observed for 24 hours for any signs of immediate complications. Pigs were sacrificed thereafter, and gross inspection of the distal esophagus and the adjacent regions was completed. Results: The longitudinal lengths of 3∼5 cm rectangular esophageal mucosal resections were performed. Spans of 1/2 circumference (1), 3/4 circumference (2), and circumferential mucosal resections (1) were completed successfully. Minimal bleedings encountered during the procedure were all controlled with epinephrine injection or simple coagulating current application. During the 24-hour observation period, none of the pigs showed evidences of bleeding, infection, or perforation. This was confirmed with post-mortem examination of the distal esophagus. Behavior of the pigs post-resection was essentially unchanged from prior to the procedure. Conclusions: Endoscopic wide mucosal resection in esophagus is feasible and appears to be safe. Potential application in Barrett's high-grade dysplasia and early cancer warrants further study of this technique.