Underwater Endoscopic Mucosal Resection With a Multiloop Traction Device for a Colorectal Tumor at the Flexure

Underwater endoscopic mucosal resection (UEMR) is effective for 10–20 mm colorectal polyps [1]. However, snaring is difficult for lesions at colonic flexures because the proximal edge is hidden by folds. We report a case of successful en bloc UEMR using a multiloop traction device (MLTD) (Boston Scientific, Tokyo, Japan).

A 72-year-old man with hypopharyngeal cancer underwent fluorodeoxyglucose (FDG) positron emission tomography, which revealed FDG accumulation in the rectosigmoid colon. Colonoscopy revealed a 20-mm protruding lesion. UEMR using SnareMasterPlus (15 mm; Olympus Medical Systems, Tokyo, Japan) was attempted. However, visualization of the oral side of the lesion was challenging, as the lesion extended across the flexure of the rectosigmoid junction (Figures 1a and 2a). Retroflex observation allowed the visualization of the oral side of the tumor; however, poor maneuverability prevented suitable snaring. Therefore, we attached MLTD to the normal mucosa 5 mm oral to the lesion using a SureClip (Micro-Tech, Nanjing, China) (Figure 1b), and subsequently hooked and anchored it to the colonic wall at the opposite side of the lesion with the second clip (Figure 1c). The traction force reduced the steep angle of the rectosigmoid junction and improved the visualization of the oral margin of the lesion in forward view (Figures 1d and 2b). We performed reliable snaring by directly observing the lesion margins (Figure 1e). The traction force optimized the visualization of the resected wound, which facilitated subsequent clipping (Figure 1f). Pathology confirmed a low-grade tubulovillous adenoma with negative resection margins.

Submucosal injection in the oral edge might also have improved lesion visibility; however, considering that unsuccessful injection carries the risk of irreversibly worsening the situation (e.g., impaired visibility due to bleeding), we first attempted this traction method, which can be undone if needed. This method has been reported in colorectal ESD [2] and duodenal UEMR cases [3], and we further confirmed its usefulness even in colorectal UEMR.

Kazuki Matsuyama performed the procedures and drafted the manuscript. Minoru Kato revised the manuscript critically. Tomoki Michida supervised manuscript preparation. All the authors have read and approved the final version of this manuscript.

Informed consent was obtained from the patient for the publication of his information and imaging data.

The authors declare no conflicts of interest.