Strength of tissue attachment to mesh after ventral hernia repair with synthetic composite mesh in a porcine model

Background: A prospective animal study involving 12 female swine aimed to measure the strength of tissue attachment to composite mesh at various time points after laparoscopic ventral hernia repair in a porcine model. Methods: Each animal had two 10 x 16-cm sheets of polypropylene/expanded polytetrafluoroethylene (ePT-FE) composite mesh laparoscopically affixed to the abdominal wall with a helical tacking device. No transfascial sutures were used. The animals were euthanized 2, 4, 6, and 12 weeks after surgery, and abdominal walls were resected en bloc with the patches. Each patch was cut into 2 x 7-cm strips, and each strip was independently analyzed. The strength of the tissue attachment to the mesh was measured using a servohydraulic tensile testing frame. The abdominal wall was peeled from the mesh, and the transverse, or "lap-shear" force was recorded. Data are reported as mean force in pounds. Results: The mean lap-shear force was 0.83 +/- 0.06 lbs at 2 weeks, 1.06 +/- 0.07 lbs at 4 weeks, 0.88 +/- 0.08 lbs at 6 weeks, and 1.13 +/- 0.07 lbs at 12 weeks. The mean force was higher at 12 weeks than at 2 weeks (p < 0.05). No other periods were significantly different from any other. Conclusion: The findings demonstrate that the majority of tissue ingrowth and strength has occurred by 2 weeks after laparoscopic placement of a composite hernia prosthesis. Strength very gradually increases until 12 weeks after surgery. This has clinical implications for human ventral hernia repair. Further study is needed to evaluate the necessity of transfascial sutures for securing polypropylene-based prostheses to the abdominal wall during ventral hernia repair.