Wall injury after colonic polypectomy : comparison between steel and tungsten snares

P0229 WALL INJURY AFTER COLONIC POLYPECTOMY: COMPARISON BETWEEN STEEL AND TUNGSTEN SNARES G. Galloro1, L. Magno1, P. Iovino1, S. Ruggiero1, T. Rappa1, C. Meola2, G.M. Carlomagno2. 1General Surgery and Advanced Technologies, 2Department of Aerospace Engineering, University of Naples Federico II, Naples, Italy INTRODUCTION/OBJECTIVES: Electrosurgical current used in polypectomy can cause thermal injury to digestive wall with complications such as bleeding, postpolypectomy syndrome, and perforation. To reduce the rate of these complications, we studied the materials snares are made of. We compared steel and tungsten endoscopic snares, evaluating the depth of colonic wall injury caused by electrosulgical current during endoscopic polypectomy on an animal model, using cut, coagulation, and blend current. AIMS & METHODS: Polypectomies were performed on a live pig, under general anesthesia, with a double channel colonoscope. To simulate the polyp stalk, the colonic mucosa was gathered into the snare by a grasper and the snare closed. Electrosurgical current was applied 15 times at each of 3 current modes. The procedure was performed using either a steel or a tungsten snare with same size, shape, and profile (Innovamedica, Milano, Italy). Colored hemoclips were used to identify the sites. After polypectomies, the colon was removed and examined by a blind pathologist. To define the reasons of behaviour of two snares, we reproduced, on an ex-vivo model, the same conditions of polypectomy described above. Thermal measurements were achieved by an infra-red thermocamera. RESULTS: There is significant difference in the depth of tissue injury in the three different current modes using both steel and tungsten snare. In details, using steel snare, coagulation provokes significant deeper tissue injury compared to pure cut (p<0.001) and blend current (p<0.05). Using tungsten snare, there is significant deeper tissue injury by coagulation compared to pure cut (p<0.01); there is no significant difference in depth of injury between coagulation and blend. Using both steel and tungsten snares there is no difference beween cut and blend. Steel snare provokes significant deeper tissue injury than tungsten snare using pure cut (p<0.05) and blend (p<0.05). There is no significant difference in depth of tissue injury between steel and tungsten snares using coagulation. About thermal behaviour of two materials, infra-red thermocamera findings show a quicker sudden rise and drop in temperature of the tungsten snare, and a better uniform standard temperature distribution, if compared to steel snare. CONCLUSION: In tungsten snare, heat is homogeneously distributed and well concentrated allowing a better and selective cut. Thermal properties of tungsten make it very well-suited for the manufacturing of electrosurgical devices. Our results suggest that tungsten should be preferred in the manufacturing of electrosurgical endoscopic devices thanks to its lower rate of thermal-related complications. Disclosure of Interest: G. Galloro: No conflict of interest to declare, L. Magno: No conflict of interest to declare, P. Iovino: No conflict of interest to declare, S. Ruggiero: No conflict of interest to declare, T. Rappa: None Declared, C. Meola: No conflict of interest to declare, G. Carlomagno: No conflict of interest to declare. Endoscopy 2010; 42 (Suppl I) A152