OWE-007 Saline-immersion therapeutic endoscopy (SITE) for endoscopic submucosal dissection (ESD) of a large rectal lesion

IntroductionSince its first description in 2012, underwater endoscopic mucosal resection has become a well-recognised alternative approach to standard submucosal-injection facilitated endoscopic mucosal resection. In 2017, our group first described Saline-immersion therapeutic endoscopy (SITE) as an ‘evolution of the underwater technique’ with several potential advantages.1 To date, only limited data concerning the use of immersion methods for endoscopic submucosal dissection (ESD) are available. Our aim was to assess the usefulness, effectiveness and safety of SITE-facilitated ESD for resection of a large rectal lesion.MethodsAn 82-year-old woman with a history of ischaemic heart disease, hypertension, atrial fibrillation, type 2 diabetes mellitus and deep vein thrombosis, was referred to our centre for ESD of a 60 mm rectal mixed-nodular type laterally spreading tumour (LST-GM) (Paris 0-Is, Kudo pit pattern IIIL/IV), 10 cm from the anal verge.ResultsSITE-facilitated ESD was performed under conscious sedation using the pocket creation method (PCM). A gastroscope with incorporated water-jet and NearFocus functions (GIF-H290, Olympus, Japan), short ST hood (Fujifilm, Japan) and a 2.5 mm FlushKnife (Fujifilm, Japan) were used. Carbon dioxide (CO2) insufflation was used during the initial incision and submucosal trimming on the anal side of the lesion. The CO2 insufflator was then turned off, gas was aspirated from the lumen and the lesion was submerged in physiological saline using the water-jet function. SITE-facilitated ESD was then performed using NearFocus mode. Saline-immersion eliminated any fluid-gas interfaces obviating the need for suction. The use of saline-immersion with NearFocus also facilitated more precise, minimal contact dissection and enhanced pre-emptive visualisation of submucosal vessels, for avoidance of intraprocedural bleeding. Once the submucosa was successfully dissected, the remaining lateral and oral incisions were completed successfully for en-bloc resection; histopathology confirmed R0 resection.ConclusionSITE-facilitated ESD appears to be a useful, safe and effective technique. In our experience, it appears to confer several potential advantages which include: improved endoscopic visualisation (with augmented magnification), minimal contact dissection (likely due to the superior electrical conductivity of saline) and also reduced tissue friability (due to the isotonic nature of physiologic saline vis-à-vis water-immersion).Refe