Clinicopathological data of 15 patients with pyloric early cancer and precancerous lesions, who received endoscopic submucosal dissection (ESD) in Zhejiang Cancer Hospital from March 2011 to January 2020 were retrospectively analyzed. Postoperative pathology showed 7 cases of low-grade intraepithelial neoplasia, 3 cases of high-grade intraepithelial neoplasia, and 5 cases of early gastric cancer. R0 complete resection was achieved in all patients. The mean operation time was 55.2 min (35-78 min). One patient had delayed postoperative bleeding, and no other complications such as bleeding, perforation or abdominal pain occurred in other 14 patients. No recurrence, metastasis or pyloric stenosis was found during the follow-up of 31.3 months (1-106 months). ESD is safe and effective for early cancer and precancerous lesions in the pylorus.

Objective:To explore the safety and efficiency of a novel bipolar electric knife for endoscopic submucosal dissection.Methods:The thermal damage on tissue caused by the new bipolar knife and traditional monopolar knife were compared by finite element analysis. The vertical thermal damage to the porcine gastric wall caused by the two types of electric knife were analyzed in vitro animal experiments. In vivo animal experiments were used to compare operation related indexes of two types of electric knife, including en bloc resection rate and cutting efficiency in porcine digestive tract submucosal dissection. Results:Through overcoming deviation of experimental individuals and operator experience, the finite element model showed that the length, width and depth of thermal damage on tissue caused by the monopolar knife was 1.08 times, 1.12 times, and 1.23 times of that of the bipolar knife, respectively. Additionally, the bipolar knife caused less vertical thermal damage to the porcine gastric wall than the monopolar knife (433.25±42.58 μm VS 898.03±111.59 μm, t=6.740, P=0.003) in vitro animal experiments when charged for 1 s at the same power. Finally, in vivo animal experiments showed that the en bloc resection rates of the two kinds of electric knife systems were both 100.0%. In addition, the cutting area and cutting time of the bipolar knife was 229.58±185.29 mm 2 and 164.37±96.27 s, respectively. The corresponding indicators of the monopolar knife was 209.70±167.35 mm 2 and 162.65±69.97 s, respectively, and there was no significant difference (all P>0.05). Conclusion:The novel bipolar knife not only ensures the cutting efficiency but also reduces the thermal damage during endoscopic submucosal dissection in simulating experiment and animal experiment, which needs further verification in clinical trial.