Mechanical Strength and Rheological Properties of Tissue Adhesives With Regard to Colorectal Anastomosis An Ex Vivo Study

Objective: To compare mechanical strength and rheology of existing tissue adhesives in a clinically relevant test setup with regard to colorectal anastomosis. Background: Little is known on the mechanical strength of tissue adhesives directly after application. Furthermore, rheological profiling may be important in understanding mechanical performance and explaining differences between adhesives. This study provides new data on the mechanical strength and rheology of a comprehensive list of tissue adhesives with regard to colorectal adhesiveness. Methods: Twelve surgical tissue adhesives were included: 4 cyanoacrylate adhesives (CA), 2 fibrin glues (FG), 3 polyethylene glycol (PEG) adhesives, and 3 albumin-based (AB) adhesives. Tubular rat colonic segments were glued together. Tensile (T), shear (S), and peel (P) strength were measured. Shear storage (G') and shear loss (G '') moduli were also evaluated. Results: CA adhesives were stronger than AB (T: P = 0.017; S: P = 0.064; P: P < 0.001), which, in turn, were stronger than PEG (T: P < 0.001; S: P < 0.001; P: P = 0.018). PEG were stronger than FG for shear (P = 0.013) and comparable for tensile and peel strength (P > 0.05). Within-group variation was smallest for CA. Mechanical strength correlated strongly between performed tests. Rheological properties (G' and G '') correlated strongly with mechanical strength for all adhesives combined. Conclusions: CA adhesives are the strongest and most homogenous group in terms of mechanical strength. Hydrogels (FG, AB) are heterogeneous, with lower mechanical strength than CA. FG are mechanically the weakest adhesives. Rheological profiles correlate to mechanical strength and may be useful for predicting mechanical performance.