Comparison between tungsten and steel polypectomy snares: evaluation of depth of colonic thermal wall injury in a pig model.

Thermal injury of the colonic wall during polypectomy may induce complications such as bleeding and perforation. To date, the role of the snare material in these injuries has not been examined. The aim of this study was to evaluate the depth of colonic post-polypectomy thermal wall injury induced by tungsten and steel endoscopic snares, in an effort to reduce electrosurgery-related complications. This was a single tertiary center experimental study in a porcine model. A total of 90 polypectomies where performed in three live pigs under general anesthesia, using both steel and tungsten snares by cut, coagulation, and blend current modes. The pigs were then euthanized and their colons examined histologically. Steel snares induced significantly deeper tissue injury than tungsten snares in the pure cut mode (Pearson χ2 = 6.136, P = 0.013). The ordinal logistic regression analysis showed that the current mode and snare material were significantly associated with the ordinal score for the depth of injury. Thus, cut mode was positively associated with a lower score and coagulation mode with a higher score. In addition, tungsten was significantly associated with a lower depth of tissue injury. Due to its inherent electrical properties, tungsten is very well suited for manufacture into electrosurgical endoscopic devices. Thus, tungsten snares may be advantageous for routine use in endoscopic polypectomy, although further studies are needed to confirm these promising findings in human patients.