Underwater versus CO₂ Environment in Endoscopic Submucosal Dissection: A Propensity Score-Matched Analysis for Large Nonpedunculated Colorectal Polyps

Aims Underwater endoscopic submucosal dissection (U-ESD) represents an emergent technique for the resection of large nonpedunculated colorectal polyps (LNPCPs). By leveraging the buoyancy effect for easier mucosal flap creation, natural optical magnification for enhanced layer recognition, and water pressure-assisted traction, U-ESD enables a more effective submucosal dissection. Additionally, replacing CO₂ with saline allows for prophylactic underwater vessel coagulation, improving submucosal vessel sealing to reduce intraprocedural bleeding. Aim of the study is to evaluate the effectiveness and safety of U-ESD compared to ESD in a CO₂ environment (C-ESD) for the treatment of LNPCPs.

Methods All consecutive LNPCPs treated by U-ESD from January 2023 to December 2023 were included. A control group of C-ESD from January 2021 to December 2022 was used for comparison. Resections were performed by six operators at a high-volume therapeutic endoscopy center. Main procedural outcomes were R0 resection, intraprocedural perforations, intraprocedural bleedings requiring the use of hemostatic forceps, delayed adverse events (AEs), and dissection speed. A propensity score matching (PSM) analysis for baseline lesion characteristics (e.g., size, location, morphology, and pit-pattern) was performed to minimize selection bias. (This study was funded by Horizon Europe Guarantee #10072975)

Results Out of 208 LNPCPs, U-ESD was performed in 77 cases, while C-ESD in 131 cases. After PSM, 82 lesions (mean size 48.5 mm, mean area 1928 mm², 47.6% rectal location, 34.1% non-granular type, 18.3% Kudo pit-pattern Vi) with 1:1 matching were included in the final analysis. U-ESD demonstrated a significantly higher rate of in R0 resection rate (97.6% vs 82.9%; 95%CI 0.975: 0.871-0.999 vs 95%CI 0.829: 0.679-0.928; p=0.02) and a significantly lower rate of intraprocedural bleedings requiring hemostatic forceps (0% vs 14.6%; 95%CI 0.000: 0.000-0.000 vs. 95%CI 0.1463: 0.038-0.254; p=0.002), compared to C-ESD. Dissection speed was significantly increased in the U-ESD group compared to C-ESD (31.8 mm²/min vs 22.9 mm²/min; 95%CI 28.170-35.430 vs 95%CI 19.560-26.240; p=0.004), while intraprocedural perforations (4.9% vs 12.2%; 95%CI 0.048: 0.006-0.165 vs 95%CI 0.122: 0.021-0.222; p=0.1), and delayed AEs (4.9% vs 4.9%; 95%CI 0.048: 0.006-0.165 vs 95%CI 0.048: 0.006-0.165; p=1.0) were similar with no statistically significant differences. No AEs required surgery [1] [2] [3].

Conclusions U-ESD significantly improves R0 resection rates, reduces intraprocedural bleedings, and enhances dissection speed compared to C-ESD. Saline environment optimizes visualization and coagulation efficiency, improving procedural outcomes. U-ESD holds promise as a cost-effective, fast, single-device technique for treating LNPCPs.

Publikationsverlauf

Artikel online veröffentlicht:
27. März 2025

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