Introduction: Indirect heat-induced attachment and detachment (iHIAD) is a promising concept for gripping delicate tissues in microsurgery. However, the optimal settings of iHIAD are unknown. This study evaluates the effects of the instrument heating properties and initial contact force on the adhesion force, detachment success and thermal damage.
Material and methods: An instrument prototype was developed to test attachment and detachment for different combinations of generated energy (3.5-20.0 mJ) and pulse length (0.25-2.50 ms). The tissues tested on were kidney and eye from the pig. Thermal tissue damage was estimated with a histological analysis.
Results: The adhesion force F(a) depended strongly on the amount of generated energy (F(a) = 0.03-2.5 mN) and contact force (F(a) = 0.25-1.0 mN). Pulse length played a minor role. Detachment success (0-100%) was determined by generated energy (3-16 mJ). Histological analysis showed minimal damage.
Conclusion: Adhesion forces increased with increasing contact forces. iHIAD proved sensitive to heating characteristics. Detachment success increased with generated energy. Thermal damage was minimal. iHIAD creates a potential to build better performing tissue manipulators.