PTU-059 Comparison Of Bipolar Radiofrequency Cutting And Mono Polar Cutting For Endoscopic Submucosal Dissection (esd) In A Porcine Model

Abstract

INTRODUCTION: Current endoscopic knives utilise mono-polar energy (transmitted from the device across the bowel wall to the return plate) to incise the mucosa, dissect the submucosa and coagulate bleeding vessels. Monopolar devices have proven efficacy but remain technically challenging to use with the risk of major complications (perforation/bleeding). AIMS & METHODS: A new bipolar endoscopic device (energy localised to the device tip) "Speedboat-RS2, Creo Medical Ltd, UK" was compared to a standard mono-polar endoscopic device (Flush-knife-BT, Fujifilm, Japan) for endoscopic submucosal dissection (ESD) in the porcine colon. The Speedboat-RS2 blade delivers bipolar radio frequency (RF-400KHz) cutting and microwave coagulation (5.8GHz) for hemostasis, and contains a retractable needle for submucosal injection/tissue irrigation. It also has an insulated hull to prevent thermal injury to the underlying muscle layer. ESD was performed and video recorded on 5 consecutive 60kg pigs. The following parameters were measured: time taken to complete resection, complications encountered and histological assessment. Two animals were recovered for one week and four animals for four weeks. RESULTS: Ten consecutive resections were performed in the colorectum (2 per animal), 5 with Speedboat-RS2 and 5 with Flushknife-BT. Median time for Speedboat RS2 to complete a resection was 44 min, range (33-58 min) using RF cutting 30W, voltage circa 300Vrms and for Flushknife-BT was 52min, range (28-67min) using monopolar cutting for mucosal incision (80W) and for submucosal dissection, monopolar forced coagulation 30W. Median flap size (longest diameter) for Speedboat RS2 was 36.8mm, range (30-42mm) and for Flushknife was 43mm, range (35-55mm). Microwave coagulation was applied for either minor bleeding or visible vessels on 25 occasions (mean energy 7.5W) with Speedboad-RS2. Monopolar coagulation was applied 14 times with Flushknife, mean energy 30W. The Hemostatic Coagrasper was used 7 times to control arteriolar bleeding during Speedboat RS2 dissection when microwave was not sufficient and only once during Flushknife-RS2 dissection. Endoclips were placed to treat deep muscle injury in the resection base on 10 occasions in the Flushknife resections (15clips placed) and on 3 occasions (3 clips) for the Speedboat- RS2 resections. There was only one study perforation - Flushknife-BT group, where urgent peritoneal decompression was required and the resection was abandoned. Histology (Speedboat-RS2 resections) showed an intact muscle layer in four resection bases and in one there was slight muscle alteration but muscle cell viability was retained. The muscle layer was absent in two Flushknife-BT resection bases and moderately altered in one. CONCLUSION: Compared to Flush knife-BT ESD colonic resections (monopolar) the Speedboat-RS2 was associated with less muscle injury and need for endoscopic clipping. However Speedboat-RS2 resections produced more intraprocedural bleeding requiring the haemostatic forceps.