Comparison of graft-reinforced repairs and suture repair using a novel biomechanical test

The aim of this study was to determine the feasibility of a novel biomechanical test for evaluating mesh-reinforced repair compared to suture-reinforced repair using an animal model. We hypothesized that the fatigue life of a mesh reinforced repair would be greater than that of xenograft reinforced repair and suture-only repair. Wistar rats were randomly assigned to undergo a ventral hernia repair using sutures or one of the three mesh materials representative of incorporation, encapsulation and resorption host responses (Gynemesh®, Pelvisoft® and Surgisis®, respectively). All surviving animals were killed at 90 days and specimens containing the prosthesis–tissue interface were exposed to cyclic forces. The number of cycles to failure (fatigue life) was compared between groups using a Cox regression model. Of 40 randomly assigned animals, 11 died before 90 days. After randomizing an additional 5 rats, a total of 34 rats were killed at 90 days. The proportions of specimens that failed before 10,000 cycles were 25 % (2/8), 50 % (4/8), 62.5 % (5/8) and 70 % (7/10) in the Gynemesh, Surgisis, Pelvisoft, and suture control groups, respectively. In addition, the median number of cycles to failure was >10,000 in the Gynemesh group, >6,923 in the Surgisis group, 1133 in the Pelvisoft group and 741 in the control group. After adjustment for cross-sectional area, the risk of failure in the suture control group was higher than in all of the reinforced repair groups combined with an adjusted hazard ratio of 2.58 (95 % CI 0.96 – 6.97), and was statistically significantly higher than in the Gynemesh group with an adjusted hazard ratio of 6.67 (95 % CI 1.30 – 34.48). We present a novel biomechanical test that can be used to compare mesh materials in an animal model prior to use in humans. In this animal model, after adjusting for cross-sectional area, suture reinforced repair has a higher risk of failure than graft reinforced repair.