The Physiological Incubation Biosimulator (PIBS): An Improved Ex Vivo Experimental Setup for the Mechanical Stability of Biological Sealants in Surgical Procedures

Background. Tissue-bound fibrin sealants are used in a wide array of surgical procedures. The microenvironmental interaction between sealant and application site is often poorly evaluated due to a lack of suitable experimental models. Methods. A physiological incubation biosimulator (PIBS) was developed to test biological sealants in an ex vivo setup under physiological conditions comparable to the microenvironment at application site (temperature, humidity, pressure). PIBS was validated by a study on the effectiveness of TachoSil for leak closure at pancreatic resection sites. Defined defects in a thoracic membrane of porcine origin were sealed by TachoSil. Integrity of the sealing was tested in the presence of active pancreatic fluid over 60 minutes. Heat-inactivated pancreatic fluid and electrolyte solution served as controls. The time to leakage was recorded and experimental groups were analyzed by Kaplan-Meier analysis. Results. PIBS produced reliable results. TachoSil lead to a leakage rate of 96% after incubation with active pancreatic fluid (p = 34), which was significantly higher compared with heat-inactivated pancreatic fluid (p = 34, 52%) or electrolyte solution (p = 20, 19%). Conclusion. PIBS is an effective tool to evaluate microenvironmental effects on the adhesive strength of biomaterials. Tissue sealing effect of TachoSil is diminished in a “pancreatic” microenvironment rich with pancreatic enzymes. Our results might therefore explain the reason of the findings of randomized controlled trials recently published on this subject.