Endoscopic submucosal dissection of colon polyps with submucosal fibrosis using the combination of near-focus mode and traction device. Lateral spreading tumor with pseudodepressed non-granular type has higher potential to contain malignancy and submucosal fibrosis than other subtypes. Therefore, unbuckling section with ESD should be considered. However, ESD of colorectal lesions with submucosal fibrosis is challenging with high risk of perforation and prolonged procedural time. Therefore, the appropriate traction method should be used such as clip-lubber band method, clip-like traction, or pocket creation method. In addition, the near-focus mode of dual-focus chronoscope may enhance visualization of the submucosal plane because the typical dissection range is within the depth of field of near-focus mode. With a dual-focus chronoscope, endoscopist can easily switch from standard focus to near-focus mode with a single push of a button. It should be noted that the depth of field may differ slightly between the models. First case, a 62-year-old female without comorbidities was presented with hematochesia. We performed colonoscopy. We found a 3.5-centimeter polyp with type 0-2A plus 2C Paris classification at the ascending colon near hepatic fracture. Magnifying NBI showed the type 2B genetic classification. So, we decided to perform ESD with a dual-focus chronoscope. The submucosal injection was performed with glycerol mixed with indigo carmine and adrenaline. We used the digital type knife to make the incision and dissect the submucosal layer. During submucosal dissection, the near-focus mode improved the visualization of submucosal plane. However, the dissection was still difficult due to submucosal fibrosis. Therefore, a cell-made silicone loop traction clip was supplied. However, the dissection was difficult due to submucosal fibrosis. The dissection plane was adequately exposed after the traction clip application. This is the difference between standard focus and near-focus mode. In the near-focus mode, we could clearly see the line of muscular dyspropria and proper dissection plane. An insulated tip knife was used during the dissection of fibrotic part. Then, we continue submucosal dissection with needle-type knife. The polyp was successfully removed, and the mucosal defect was caused using endoscopic clips. The procedural time was 100 minutes. There was no complication. The pathology examination showed intermucosal adenocarcinoma with greatly sectioned margins. Second case, a 60-year-old female underwent a screening colonoscopy. A 2.5-centimeter polyp with type 0-2A plus 2C Paris classification was found at the incending colon. Magnifying NBI showed a type 2B genetic classification, so we performed ESD. Pore lifting at the center of the lesion was seen after submucosal injection. We used the digital type knife to make the incision and dissect the submucosal layer. Because of submucosal fibrosis, we applied a self-made silicone loop fraction clip. During dissection of fibrotic part, near-focus mode improves visualization of proper dissection plan. This is the final cut. The mucosal defect was caused with endoscopic clips. The procedural time was 15 minutes. There was no complication. The pathology examination showed tubular adenoma with high grade dyspatia and clearly sectioned margins. Clinical implications. Traction device is helpful during ESD of the colorectal polyp with submucosal fibrosis. Near-focus mode of a dual-focus chronoscope may enhance visualization of the submucosal plane. The typical dissection range is within the depth of field of near-focus mode. In conclusion, the combination of near-focus mode and traction device may be helpful during ESD of colon polyp with submucosal fibrosis because they improve the visualization of submucosal plane.

endoscopic submucosal dissection

colon polyps

submucosal fibrosis

traction device

near-focus mode