UNDERWATER TECHNIQUE IMPROVES DISSECTION SPEED IN COLORECTAL ENDOSCOPIC SUBMUCOSAL DISSECTION

Aims Colorectal endoscopic submucosal dissection (ESD) is a technically difficult, time-consuming and sometimes risky procedure. Tissue traction and good submucosal exposure are important factors for an effective, safe dissection. Underwater ESD (U-ESD) consists in performing an ESD in water or saline immersion, this technique provides multiple advantages, is inexpensive and easy to perform. This study evaluated underwater ESD (U-ESD) as compared to conventional ESD (C-ESD) for dissection of superficial colorectal tumors. Methods We retrospectively analysed colorectal ESD performed in our centre between January 2014 and September 2021. After excluding patients with IBD, recurrent lesions and those removed by hybrid technique 148 colorectal superficial neoplasms were considered, 28 were removed by U-ESD, 120 by conventional ESD. The primary outcome was dissection speed; secondary outcomes were R0 resection rate and the rate of adverse events. Results Table 1 U-ESD N 28 C- ESD n 120 p value Age, years, mean + SD 68,6 + 9.5 69,2 + 10,4 0.7845 Gender (male/female) 16/12 63/57 0.6574 Location, n (% ) Right colon 12 (42.9) 22 (18.3) 0.0055 Left colon 6 (21.4) 27 (22.5) 0.9024 Rectum 10 (35.7) 71 (59.2) 0.0248 Macroscopic type, n (%) LST-NG 10 (35.6) 38 (31.6) 0.6804 LST-G 18 (64.3) 61 (50.9) 0.1988 Sessile 0 21 (17.5) 0.0434 Area, cm 2 , mean (SD) 12.56 (10.97) 10.05 (13.95) 0.3796 Pathological diagnosis, n (%) LGD 2 (7.1) 4 (3.3) 0.3176 HGD 19 (67.9) 85 (70.8) 0.7564 T1 7 (25) 30 (25) 1 Dissection speed, mm2/min, mean + SD 17.7 + 10.7 13.0 + 8.4 0.0130 R0 resection, n (%) 28 (100) 110 (91.7) 0.2092 Adverse events (%) 0 3 (2.5) 1 Perforation 0 1 (0.8) Bleeding 0 2 (1.7) There were no differences in patients characteristic and hystologycal type between the two groups. Lesions in U-ESD group were predominantly located in proximal colon ( p=0.0055 ); neoplasm in C-ESD group were mostly located in rectum ( p=0.0248 ) and were mainly of sessile morphology ( p=0.0434 ). Dissection speed was significantly higher in U-ESD group (mean 17.7 mm 2 /min vs 13.0 mm 2 /min, p=0.0130 ); there were no significant differences in R0 resection rate (100% vs 91.7%, p=0.2092 ) and adverse events rate (0% vs 2,5%, p=1 ). Conclusions Underwater ESD is a safe, effective, inexpensive and easy to perform technique for dissection of superficial colorectal neoplasm. UESD improved submucosal dissection speed compared to conventional ESD. Publication History Article published online: 14 April 2022 © 2022. European Society of Gastrointestinal Endoscopy. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany