Abstract / Summary
Underwater endoscopic submucosal dissection (UESD) has emerged as a promising alternative to conventional techniques, offering advantages for colorectal neoplasms. However, intraoperative bleeding in the fluid field remains a major challenge, often disrupting procedural rhythm and prolonging operative time. While the spray coagulation mode of electrocauterization improves hemostasis in conventional ESD in the air-filled lumen environment, its efficacy in the underwater environment is unknown. We aimed to evaluate the clinical outcomes of colorectal UESD and assess the impact of high-power spray coagulation (HP-spray) on procedural efficiency. This single-center retrospective cohort study included 56 consecutive patients undergoing UESD for colorectal neoplasms ≥ 20 mm between January 2024 and October 2025 in a tertiary referral medical center. Thirty procedures used conventional coagulation (Swift coagulation 4.5 or PreciseSECT 4.5) and 26 used high-power spray (mode 7, VIO3) coagulation. The primary outcome was procedural efficiency, defined as the completion of UESD within 60 min. Univariable and multivariable logistic regression analyses were performed to identify factors independently associated with timely completion. HP-spray was associated with a higher likelihood of UESD completion within 60 min (adjusted OR 3.99, 95% CI 1.03–15.46; P = 0.045), whereas tumor size ≥ 30 mm was associated with a lower likelihood of timely completion (adjusted OR 0.05, 95% CI 0.01–0.27; P < 0.0001). The number of intraprocedural bleeding episodes requiring hemostatic forceps exchange was lower with HP-spray than with conventional coagulation (mean ± SD, 0.15 ± 0.37 versus 0.53 ± 0.78; P = 0.050). En bloc resection was achieved in 100% of cases (30/30 conventional, 26/26 HP-spray), and R0 resection in 92.9% overall (27/30 conventional, 25/26 HP-spray; P = 0.615). Intraprocedural microperforation occurred in two cases (3.6% overall; 1 conventional, 1 HP-spray), all managed endoscopically; no delayed bleeding or delayed perforation occurred in either group. HP-spray coagulation as a knife-based vessel management strategy during UESD was associated with greater procedural efficiency and a lower burden of intraprocedural bleeding requiring hemostatic forceps exchange in our study. Further prospective multicenter studies are warranted to validate its integration into the standardized UESD workflow.