Endoscopic Submucosal Dissection Using the Newly Developed Ball-Tip Bipolar Current Needle Knife Is Safe and Effective Technique for Large Colorectal Tumors

Abstract

Background: We previously reported on the safety and usefulness of the bipolar current needle knife (B-knife) for colorectal endoscopic submucosal dissection (ESD). There remains a slight risk of perforation, however, so we developed a B-knife with a ball-shaped tip at the end of the needle which further reduces the risk of perforation. Objective: The aim of this study was to evaluate the safety and efficacy of ESD using the newly developed ball-tip B-knife compared with using a conventional B-knife. Design and setting: Case series conducted at the National Cancer Center Hospital (NCCH), Tokyo, Japan. Patients: Patients with 300 colorectal LSTs were included in this study between January 2003 and November 2007. Through December 2006, 229 colorectal tumors were treated by ESD using a conventional B-knife while 71 colorectal tumors were treated by ESD using the ball-tip B-knife beginning in January 2007. Interventions: ESD procedures were performed using a B-knife and insulation-tip knife (IT knife). After injection of glycerol and sodium hyaluronate acid into the submucosal (sm) layer, a circumferential incision was made and sm dissection was performed. All lesions were determined to be intramucosal or sm superficial by magnified colonoscopy before treatment. Main outcome measurements: We recorded tumor size, operation time, en-bloc resection rate and complications. Results: A total of 300 colorectal ESDs were performed. Mean tumor size was larger in the second group using the ball-tip B-knife with an average resected specimen size of 45 mm (range, 20-120 mm) compared to the first group using a conventional B-knife with an average resected specimen size of 37 mm (range, 20-150 mm). There were no significant differences in operation times and en-bloc resection rates between the two groups. Most importantly, there were no perforations in the second group using the ball-tip B-knife. Limitation: The number of ESDs using the ball-tip B-knife in our series was limited and there was a possible learning curve in the first group when using a conventional B-knife. Conclusion: ESD using the newly developed ball-tip B-knife is a safe and effective technique for large colorectal tumors.