Tissue grasping damage often occurs in minimally invasive surgery, which would increase the postoperative recovery time and the risk of surgical complications. The purpose of this study was to evaluate the relationship between liver tissue trauma and compression stress magnitude and duration during tissue clamping operation.Methods:
The clamping experiments of liver tissues in vivo were conducted by using a universal soft tissue mechanical testing machine under different clamping stress magnitudes and durations. The rabbit liver was used to simulate human liver. A minimally invasive surgery grasper was used in these tests to simulate the real tissue-surgical operation condition. A pathological grading system was created to quantitatively assess the trauma within the liver tissue. The hyperbolic regression models were utilized to predict the trauma degree of liver tissue.Findings:
Obvious hyperemia, hemorrhage, hepatic capsule rupture and inflammatory cell infiltration appeared in the clamping sites of the liver. Assessment results indicated that the trauma degree increased nonlinearly with the increasing clamping stress and duration time. There exist safe thresholds, in which the severe trauma of the studied tissue can be avoided during grasping operation.Interpretation:
The results could provide the safety margins and the trauma prediction models for surgeons during grasping and palpation tasks in minimally invasive surgery.