The biomechanical effects of tight suture closure upon fascia.

The biomechanical effect of tight suture closure of fascial incisions in male rats was evaluated. The incision of rats in group 1 was closed with maximum tension on the first throw of the approximating knot. The incision of rats in group 2 was closed in a similar manner, however a 3.14 squared millimeter rod was placed in the suture loop before securing the first throw. The rod was removed after the knot was formed and fascial edges were observed to be loosely approximated. All rats were sacrificed after seven days. The abdominal fascial and muscle unit was dissected and a 1 by 6 centimeter strip containing two suture loops was excised. Scanning electron microscopic examination of tissue specimens, tensile strength measurements and energy-to-failure under tensile loading studies were performed. Specimens for hydroxyproline assay were obtained from the tissue immediately surrounding the incision and between two suture loops. The scanning electron microphotographs of group 1 showed tissue overlap from the excessive force on the initial knot throws. Wounds loosely approximated had proper alignment of the wound edges and had greater proliferative activity in the clefts of the wounds. The tensile strength and energy-to-failure studies showed loosely approximated wounds to be far stronger (p less than 0.001). No statistically significant difference (p greater than 0.05) was found between hydroxyproline assays of the two groups.