739: Can placenta percreta be eliminated? Augmenting healing at cesarean delivery with a biologic graft

Full thickness defects in myometrial healing after hysterotomy appear related to subsesquent risk for placenta percreta. Our purpose was to evaluate scar thickness and tensile strengthin ewes undergoing a unique repair strategy. At 135-140 days gestation, 17 ewes underwent hysterotomy in the lower segment. Ewes were randomized between a single-layered, locking suture closure (n=8), or the same technique with an intervening biologic graft (small intestinal submucosa, Biodesign, Cook Biotech Inc., West Lafayette, Ind.), (n=9). 6 months post-delivery, the myometrial thickness and tensile strength of incisions were assessed in 6 control and 6 grafted ewes. The remaining 5 animals (3 graft:2 control) were rebred. These animals were delivered at 130-140 days gestation of the subsequent pregnancy. Tensile strength and myometrial thickness were compared by nonparametric testing. Histologic examination assessed for atypical reactions. Approval was obtained by the Animal Care and Practice Committee before experimentation. The median hysterotomy closure time was increased by 2 minutes for the graft group, P=.002. At 6 months, the tensile strength of hysterotomy site did not differ between groups assessed by the Peak Tensile Load before breakage, median 5.9 N (range 2.3-8.1 N) for grafted repairs vs. 5.4 N (range 3.6-6.5 N) for controls, P=.687. When comparing all grafted and control hysterotomy closures, the myometrial thickness was significantly increased in the grafted repairs vs. controls, median 4.5 mm (range 2.9-11.2 mm) vs. 3.1 mm (range 1.7-4.5 mm), P=.023. Myometrial integrity was present at delivery in all rebred ewes. Histologic examination indicated mature scar formation in all groups. Myometrial thickness can be increased by the use of a biologic graft at the time of hysterotomy closure. This increased thickness remained evident during a prolonged observation interval including subsequent pregnancy. Thicker repairs could lead to a marked reduction in placenta percreta.