Viscosity: An important factor in predicting the performance of submucosal injection materials

Abstract

Viscous submucosal injection materials (SIMs) that are clinically used in endoscopic treatments for early gastrointestinal cancer and polyps contribute to the treatment effects. However, the relationship between SIM characteristics [such as injection pressure (IP) and submucosal elevation height (SEH)] and viscosity has not been evaluated. The aim of this study was to analyze this relationship and elucidate whether it is possible to predict the SIM characteristics by viscosity measurements. Viscosity, IP, and SEH of conventional and developing SIMs were measured, and the correlation between these values was evaluated. A newly developed measurement model accurately measured IP. The magnitude of IP increased as the endoscopic injection needle gauge, injection speed, and concentration of SIM were increased. The strongest correlations were observed between viscosity at a shear rate of 103 s−1 and IP (correlation coefficient > 0.9, p < .01) and between viscosity at a shear rate of 100 s−1 and the SEH (correlation coefficient > 0.9, p < .01). This study defined the viscosities that represent the SIM characteristics. These findings will contribute to the design and accelerate the development of suitable high-performance SIMs by eliminating complex characterization methods.