Recent Development of Techniques and Devices in Colorectal Endoscopic Submucosal Dissection

Colorectal endoscopic submucosal dissection (ESD) is now a well-established endoscopic treatment for early-stage colorectal neoplasms, especially in Asian countries, including Japan. Despite the spread of colorectal ESD, there are still situations in which achieving successful submucosal dissection is difficult. Various novel techniques and devices have been developed to overcome these difficulties, and past reports have shown that some of these strategies can be applied to colorectal ESD. We review several recent developments in the field. The techniques reviewed include the pocket creation method and traction methods and the devices reviewed include the overtube with balloon and electrosurgical knives with water-jet function. These improved techniques and devices can facilitate safer, more reliable ESDs and expand its applicability and acceptability all over the world.

Complications Related to Gastric Endoscopic Submucosal Dissection and Their Managements

Endoscopic submucosal dissection (ESD) for early gastric cancer is a well-established procedure with the advantage of resection in an en bloc fashion, regardless of the size, shape, coexisting ulcer, and location of the lesion. However, gastric ESD is a more difficult and meticulous technique, and also requires a longer procedure time, than conventional endoscopic mucosal resection. These factors naturally increase the risk of various complications. The two most common complications accompanying gastric ESD are bleeding and perforation. These complications are known to occur both intraoperatively and postoperatively. However, there are other rare but serious complications related to gastric ESD, including aspiration pneumonia, stenosis, venous thromboembolism, and air embolism. Endoscopists should have sufficient knowledge about such complications and be prepared to deal with them appropriately, as successful management of complications is necessary for the successful completion of the entire ESD procedure.

Preoperative Iodine Staining May Complicate the Demarcation of Esophageal Carcinoma

A 53-year-old man was suspected of having an esophageal neoplasm. An endoscopic examination including Lugol chromoendoscopy suggested an esophageal squamous cell neoplasm limited to the lamina propria. A targeted biopsy showed atypical squamous cells, and an endoscopic submucosal dissection was performed 22 days after the previous endoscopy. Although a single 40 mm unstained area was observed by preoperative Lugol chromoendoscopy, intraoperative endoscopy revealed a 25 mm iodine-unstained area, with small unstained areas scattered on the oral side. We included the small unstained areas in the extent of the resection through assessment by preoperative endoscopy. Histopathologically, the tumor extent appeared to coincide with the preoperative assessment. Tumor cells were found in the basal-parabasal layers of the mucosa, in which small unstained areas were scattered, although the superficial layers exhibited well-differentiated cells containing glycogen in the cytoplasm. Although Lugol chromoendoscopy, which can induce chemical esophagitis, is widely used, re-epithelialization after mucosal damage by preoperative iodine staining may complicate the intraoperative demarcation of tumors.

Short-Term Healing Process of Artificial Ulcers after Gastric Endoscopic Submucosal Dissection

BACKGROUND/AIMS: The relationship between the appearance of an ulcer and postoperative bleeding after gastric endoscopic submucosal dissection (ESD) is not well understood. To explore this potential relationship, we retrospectively analyzed the short-term healing process of ESD. METHODS: A total of 520 consecutive lesions in 434 patients seen between January 2004 and December 2009 were retrospectively investigated. At the second-look endoscopy, which occurred between 1 and 8 days after ESD, artificial ulcers were categorized into 6 patterns according to Forrest's classification: spurting bleeding, oozing bleeding, non-bleeding visible vessel, adherent clot, black base/spot, and clean base. From these data, a short-term healing model of the artificial ulcer was generated. RESULTS: Ulcer base changed gradually from a bloody to a clean one. The bleeding or non-bleeding visible vessel categories, which occurred in approximately one quarter of the ulcers within 3 days of ESD, were rarely observed 4 days after ESD. CONCLUSIONS: Ulcers that occur after gastric ESD heal in line with a specific time course, and it appears that most healing occurs without massive bleeding.

Submucosal Injection of Normal Saline can Prevent Unexpected Deep Thermal Injury of Argon Plasma Coagulation in the in vivo Porcine Stomach

BACKGROUND/AIMS: There have been several reports of thermal injury induced by argon plasma coagulation (APC) in animal models, but no follow-up studies have revealed the actual thermal injury. METHODS: APC was performed on the stomachs of two living minipigs with and without prior submucosal injection of normal saline. The power and argon gas flow were set to 60 watts and 2 L/min, respectively, and pulse durations of 5, 10, and 20 seconds were used. One of the minipigs was killed immediately thereafter and the other was killed 1 week later. RESULTS: The minipig killed immediately showed only subtle differences between noninjected and injected injuries under all the conditions, and the usefulness of prior submucosal injection was not obvious. However, the minipig killed 1 week later had a deep ulcer extending to the deeper muscle layer at the noninjected site where APC had been applied for 20 seconds, whereas tissue injury of the injected site was limited to the submucosal layer. CONCLUSIONS: Unexpected tissue damage can occur even using a short-duration APC. Prior submucosal injection for APC might be a safer alternative technique, especially in a thinner and narrower gut wall.

Submerging Endoscopic Submucosal Dissection Leads to Successful En Bloc Resection of Colonic Laterally Spreading Tumor with Submucosal Fat

A 72-year-old female with a colonic laterally spreading tumor (LST) was referred to our department. A total colonoscopy revealed a large nongranular LST, 30 mm in diameter, in the ascending colon. Detailed examination with chromoendoscopy confirmed that the lesion was an intramucosal tumor, and endoscopic submucosal dissection (ESD) was performed. After a circumferential incision around the lifted lesion with a submucosal fluid cushion, diffuse adipose tissue was observed in the submucosal layer beneath the lesion. The endoscopic view was blurred when dissecting the submucosal layer due to fat adhering to the lens. Since this made it difficult to continue the procedures, we infused water into the lumen and kept the endoscope tip immersed in the collected water. The resulting improved view made it possible to complete all procedures without withdrawing the endoscope to wipe the lens. The lesion was successfully resected en bloc without complications. The pathological examination indicated the curative resection of a tubulovillous adenoma. We propose that a submerged ESD could also be an effective procedure for colonic neoplasms with submucosal fat by avoiding blurring of the endoscopic view.