Acetic acid-assisted underwater endoscopic mucosal resection for successful resection of sessile serrated lesions

Underwater endoscopic mucosal resection (UEMR) has become the new standard of endoscopic resection of ≥ 10-mm non-pedunculated colonic polyps [1] [2] [3] [4]. It is particularly difficult to delineate the margins of sessile serrated lesions (SSLs). Though submucosal injection of a blue-colored dye mixture (e. g., indigo carmine or methylene blue) is used to enhance these lesions, SSLs tend to expand owing to the injection of the dye. Hence, bigger snares are utilized or more pieces of resection are needed, resulting in bigger defects after removal or non-en bloc resection.

We present two endoscopic resection cases using a new acetic acid-assisted underwater technique for two SSLs. The lesions were both classified as Paris-IIa; they demonstrated Kudo type II open pits and were located in the right-side colon. The first and second lesions were 12 mm and 15 mm in diameter, respectively. In both cases, 10 mL of 1.5 % acetic acid was applied over the lesion using a syringe. We confirmed the margin of the polyps easily by observing the acetowhitening reaction [5]. The lumen was then filled with saline using the water-jet function of the scope. In contrast to the approach using carbon dioxide, the persistent effect of acetic acid and the lack of mucus production were observed under the water. Thus, the margins of the lesions were clearly delineated throughout the snaring process ([Fig. 1], [Fig. 2]). Furthermore, the color change remained evident despite direct strong application of water onto the polyp. En bloc resection was achieved for both lesions. The persistence of the acetowhitening effect post-resection aided in ensuring no tissues from the lesion were left at the margin of the defect ([Video 1]).

Fig. 1 The margin of the sessile serrated lesion was delineated with acetic acid throughout the snaring process in case 1.

Fig. 2 The margin of the sessile serrated lesion was delineated with acetic acid throughout the snaring process in case 2.

Video 1 Two cases of colonic sessile serrated lesions treated with acetic acid-assisted underwater endoscopic mucosal resection.

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Competing interests

The authors declare that they have no conflict of interest.

Acknowledgement

We would like to thank Editage (www.editage.comwww.editage.com) for English language editing.

• References

• 1 Binmoeller KF, Weilert F, Shah J. et al. “Underwater” EMR without submucosal injection for large sessile colorectal polyps (with video). Gastrointest Endosc 2012; 75: 1086-1091
• 2 Li D-F, Lai M-G, Yang M-F. et al. The efficacy and safety of underwater endoscopic mucosal resection for ≥ 10-mm colorectal polyps: systematic review and meta-analysis. Endoscopy 2021; 53: 636-646
• 3 Lupu A, Rivory J, Fabritius M. et al. Consecutive cold/hot underwater snaring with a single hybrid snare for resection of large sessile serrated lesions when cold snaring fails. Endoscopy 2020; 52: E241-E242
• 4 Choi AY, Moosvi Z, Shah S. et al. Underwater versus conventional EMR for colorectal polyps: systematic review and meta-analysis. Gastrointest Endosc 2021; 93: 378-389
• 5 Yamamoto S, Varkey J, Bhandari P. Acetoelectronic chromoendoscopy for sessile serrated polyp. Gastrointest Endosc 2021; 93: 267-268

Publication History

Article published online:
15 October 2021