Friction behavior at minimally invasive grasper/liver tissue interface

Preliminary simulations of tissue clamping and dragging operations in MIS were made by using compression and friction testing under different clamping forces and dragging speeds. Results showed that the injury degree of the liver gradually increased with increasing clamping force. The maximum static friction force increased with increasing clamping force and dragging speed, and dragging displacement before sliding increased with increasing clamping force and decreasing dragging speed, which indicated that low clamping force and high dragging speed may be more likely to cause slipping at the jaw-liver interface. There exists a safe operation zone, in which there was neither liver damage nor slipping at the jaw-liver interface. The results can provide safe thresholds for doctors during grasping task in MIS.