Preliminary study on endoscopic trans-esophageal submucosal tunneling surgery : a new therapeutic approach

Background: Natural orifice transluminal endoscopic surgery (NOTES) provides minimally invasive alternative access to the peritoneal cavity, avoiding abdominal wall incisions. The current study presents a new therapeutic approach, endoscopic trans-esophageal submucosal tunneling surgery (EESTS), aiming to protect overlying mucosa to the maximum extent. Some preliminary explorations were carried out for preoperative localization, surgical positioning, incision approaches of the muscularis propria, and differentiation of endoscopic and standard anatomic images. Methods: In this study, 27 porcine corpses were tested. The developed method was divided into 4 parts. In part 1, 6 pigs were randomly divided into two groups: methylene blue solution group (ML-group) and control group (CT-group). The duration of operation starting from the creation of the tunnel incision up to the entering of the endoscope into abdominal cavity was recorded. In part 2, 9 pigs were randomly divided into three groups, L-group: fixed in the left-lateral position, S-group: fixed in the supine position, and RR-group: fixed in the raised right shoulder position. Difficulties related to the operation and endoscopic view were also recorded. In part 3, 9 pigs were randomly divided into three groups: transverse full-thickness incision group (T-group), longitudinal full-thickness incision (Lgroup), and progressive longitudinal full-thickness incision group (PL-group). In part 4, EESTS was performed to record and differentiate endoscopic and standard anatomical images. Results: In part 1, duration of the operation in the ML-group (21.67 ± 2.08 minutes) was shorter than that in the CTL-group (15.00 ± 3.00 minutes). In part 2, the RR-group presented with a better entrance site, shorter duration of operation (14.7 ± 1.5 minutes), straight tunnel, appropriate endoscopic vision, and easier operation. In part 3, the PL-group with a 2-cm incision length had proper flexibility of the endoscope and a straight tunnel, which could also be used for future operations. In part 4, the abdominal aorta, left hepatic lobe, inferior vena cava, splenic vein, gastric fundus, and spleen pancreas were observed under different endoscopic conditions. Conclusion: The raised right shoulder position, preoperative localization, and progressive longitudinal full-thickness incision were optimally achieved. In addition, endoscopic images were recorded in all positions. This represents a proper basis for future surgeries.