Background and aims: Making an optimal and lasting submucosal cushion is critical for endoscopic submucosal dissection. The thermo-sensitive binary hydrogels system composed of poloxamer 407 and poloxamer 188 might be an excellent submucosal injection solution considering the unique feature that it remains liquid at room temperature and becomes gelatinous after being injected in the submucosa of the digestive tract. The present study focuses on preparing the thermo-sensitive binary hydrogels system and testing its capacity in mucosal lifting and its role in the endoscopic submucosal dissection procedure.
Methods: Various concentrations of poloxamer 407 and poloxamer 188 were added to normal saline. The gelation temperature viscosity of the thermo-sensitive binary hydrogels system was measured to choose the best formula. The thermo-sensitive binary hydrogels system and normal saline were first compared in extracted porcine stomach. For in vivo study, the thermo-sensitive binary hydrogels system and normal saline were compared for facilitating the endoscopic submucosal dissection procedure.
Results: Among the 46 kinds of thermo-sensitive binary hydrogels system, gelation temperatures of the thermo-sensitive binary hydrogels system I (poloxamer 407/poloxamer 188, 17%/0.5%, w/w) and the thermo-sensitive binary hydrogels system II (poloxamer 407/poloxamer 188, 18%/2%, w/w) were among the ideal range of gelation temperature. The injecting pressure in vitro study of thermo-sensitive binary hydrogels system II was significantly higher than that of thermo-sensitive binary hydrogels system I and normal saline (p < 0.001). Sixteen gastric endoscopic submucosal dissection procedures were performed in a porcine model. The initial volume of normal saline injection (13.88 ± 3.91 ml vs 5.88 ± 3.44 ml, p = 0.001) was significantly larger than the thermo-sensitive binary hydrogels system group. The postoperative wound showed a significant difference in the two groups (p = 0.023) indicating that the thermo-sensitive binary hydrogels system can create a cleaner wound.
Conclusions: Considering the gelation temperature, viscosity, injection pressure, and the height of the mucosal elevation, the thermo-sensitive binary hydrogels system I was the better submucosal injection solution.
Keywords: Thermo-sensitive binary hydrogels system; endoscopic submucosal dissection; submucosal injection.