A suture-tissue pullout model in the rat abdominal wall

The suture pullout through tissue is the major cause of dehiscence. The paper presents a biomechanical model of suture pullout through the rat abdominal wall. It also studies the effect of some factors on the suture pullout force: incision orientation, knot configuration, suture material, gauge size and strain rate. Transverse and vertical incisions were made in the rat abdominal wall. Specimens were cut according to the standard test method for tensile properties of plastics by use of microtensile specimens corresponding to ASTM D 1708-84. The specimens were sutured with interrupted knots of either silk or nylon using two sizes: 2/0 and 4/0. Three different knot configurations were tested. The specimens were mounted on Zwick 1446 Universal tensile machine and the load is applied gradually at 100 mm/min until the tissue tears through the suture knot. Different strain rates were used: 50, 100, 150, 200 mm/min. The evaluation of the results was determined using multi-way ANOVA test with significance level 0.05. The incisional direction, knot configuration, strain rate were important factors in determining the suture pullout force. However, the gauge size did not affect the suture pullout force.