ESD procedures

All ESD procedures were carried out by a single experienced endoscopist (M.O.), using a single-channel video endoscope with water jet function Pentax EC38-i10 L (Pentax America, Montvale, New Jersey, United States). M.O. started performing ESD in 2014 and had performed more than 500 ESDs at the time of writing this manuscript. DEIP became available in our center in September 2017, and all colon ESDs done prior to that time were performed using a standard ESD approach (18 lesions). Training using the DEIP was completed by performing ESD using the device in an animal model for a total of five procedures in two training sessions. Then, we started to perform ESD using DEIP at Baylor College of Medicine. Two DEIP procedures were performed in 2017. In 2018, 17 colonic lesions were removed with a standard colonic ESD approach versus five lesions removed with DEIP. In 2019, 14 colonic lesions were removed with a standard ESD approach and 53 lesions were removed by DEIP. The choice between the approaches was left to the endoscopist’s preference based on the availability of the device or endoscopy staff familiar with operating the device at the time of the procedure.

For standard ESD, a transparent plastic cap (Disposable Distal Attachment, Model D-201 – 15004; Olympus America Inc., Center Valley, Pennsylvania, United States) was fitted to the distal end of the colonoscope. For DEIP, a U.S. Food and Drug Administration-approved commercially available double-balloon endoluminal intervention platform (DiLumen, Lumendi, Westport, Connecticut, United States) was used. This platform comprises a flexible sheath with two independently inflatable balloons (fore and aft balloons). The endoscope passes through the sheath using a gel lubricant with a 1-cm endoscope tip projecting out of the sheath. Endoscope tip stability is ensured by the aft balloon, while flattening of the mucosal folds with lesion retraction is provided by the fore balloon ⁸ .

Submucosal injection of compound solution composed of 500 CC of HESPAN (6 % hetastarch in 0.9 % sodium chloride), 1 cc of epinephrine, 1:10,000,0.1 mg/mL, and 3 cc of methylene blue (1:20000 mL) was used to lift the lesion-bearing mucosa. Incision of three-quarters of the circumference with a DualKnife (Olympus America Inc., Center Valley, Pennsylvania, United States) to reach the submucosal plane of dissection was then performed to allow adequate retention of the submucosal injectate. The incision was performed using Endocut Q mode (3,3,3) of Erbe VIO 200 s generator (Erbe USA Marietta, Georgia, United States). After identification of the submucosal plane, repeated injection and dissection was performed using Swift Coag mode (Effect 3, watt: 35) followed by completing the circumferential incision to ensure resection of the lesion in one-piece fashion (en bloc resection method). Whenever needed, carbon dioxide insufflation was done using a CO ₂ EFFICIENT Endoscopic Insufflator STERIS (Mentor, Ohio, United States). For hybrid ESD, a snare was used for the final resection step after performing partial submucosal dissection with the DualKnife (Olympus America, Center Valley, Pennsylvania, United States) using dry cut current and swift coagulation mode for dissection. A coagulation grasper (Olympus America, Center Valley, Pennsylvania, United States) was used to control intraprocedural bleeding. After the resection was completed, the lesion was extracted and mounted over cardboard with small pins with careful examination of the lesion’s border. The decision to resort to hybrid ESD was made by the operator (M.O.). Reasons for switching to hybrid ESD were: 1) lack of traction of the dissected part of the lesion; 2) inability to stabilize the endoscope with respect to target lesion to allow sufficient dissection and 3) expediting the procedure in case of micro-perforation or hemodynamic instability.

Study variables collected were patient age, gender, body mass index (BMI), size and location of the lesion, successful completion of en bloc and curative resection (yes/no), histopathological examination of the lesion, and ESD operative and postoperative complications.