An innovative next-generation endoscopic submucosal injection material with a 2-step injection system (with video).

BACKGROUND AND AIMS Next-generation submucosal injection materials (SIMs) with higher performance and flexibility than the current SIMs (eg, 0.4% sodium hyaluronate solution [HA]) are expected to improve endoscopic submucosal dissection (ESD) outcomes but are difficult to develop. We developed a next-generation SIM by devising a 2-solution-type SIM comprising 2.0% calcium chloride solution (Ca) and 0.4% sodium alginate solution (SA) and evaluated its performance. METHODS Viscoelasticity, submucosal elevation height (SEH), and injection pressure (IP) of HA, SA, and the next-generation SIM were measured. Outcomes of ESDs on pseudo-lesions in ex vivo porcine stomach/colon models were compared. RESULTS The dramatic increase in SA viscoelasticity through Ca addition facilitated the formation of highly viscous submucosal cushions that can be controlled by endoscopists. The SEH of the next-generation SIM was significantly higher than that of HA or SA with the same IP. The ESD procedure time using the next-generation SIM was significantly shorter than that using HA or SA (14.2 ± 6.1 vs 29.2 ± 9.1, P = 0.0004, or 14.2 ± 6.1 vs 29.1 ± 5.9, P < 0.0001). Furthermore, the total injection volume for the next-generation SIM was considerably lower than that for HA or SA (7.0 ± 0.9 vs 17.2 ± 3.4, P < 0.0001, or 7.0 ± 0.9 vs 16.2 ± 2.9, P < 0.0001). CONCLUSIONS We developed an ideal next-generation SIM that achieved high performance and high flexibility in ex vivo models. Our findings warrant its further investigation in a patient population.