CARBON DIOXIDE SUBMUCOSAL INJECTION CUSHION : AN INNOVATIVE TECHNIQUE IN ENDOSCOPIC SUBMUCOSAL DISSECTION

Aim:  Endoscopic submucosal dissection (ESD) can successfully resect large lesions en bloc, but it requires a satisfactory submucosal (sm) injection agent for proper safety and efficacy. The aim of the present study was to evaluate the effectiveness of carbon dioxide (CO2) as an ESD sm injection agent. Methods: In vitro study using porcine stomachs compared CO2 with normal saline (NS) and sodium hyaluronic acid (SHA) solution, both of which are currently used to provide long-lasting sm elevation during ESD. Histopathological examination assessed differences between CO2 and NS sm cushions. ESD were then carried out in vivo in the stomach and rectum of a live pig using CO2 sm injection. Results:  CO2 sm elevation was significantly longer lasting than either NS or SHA (P < 0.001). Histopathology revealed no mucosal layer tissue damage, and dissection of honeycomb-like fibrous connective tissue in the CO2 sm cushion. Creating and maintaining a CO2 sm cushion of sufficient elevation combined with partial physical dissection of the sm layer was achieved, followed by complete endoscopic dissection of the sm layer with all ESD, resulting in successful en-bloc resections having a mean specimen size of 24.3 mm within 15 min. Conclusion:  Safety and efficacy of CO2 as a satisfactory sm injection agent during ESD was successfully demonstrated in these preliminary studies, warranting further investigation of this innovative technique.