Preliminary experimental study on intrauterine abdominal wall defect repair of fetal lamb at late pregnancy

Objective To evaluate the feasibility of intrauterine abdominal wall defect repair of fetal lamb at late pregnancy.Methods Eight healthy pregnant ewes at 110-115 days of gestation(weighing 14-22 kg) were randomly divided into 2 groups.In group A(n=3),the abdominal wall defect of 5 cm × 1 cm was made in the fetal lambs,then was closed by strengthening suture;in group B(n=5),the abdominal wall defect of 5 cm × 2 cm was made in the fetal lambs,then was repaired by 2 layers of biological patches.After the lambs delivered naturally,the lambs and their wounds were observed;at 10th day after birth,the scars were harvested for biomechanical and histological observations.Results One ewe of group A and 2 ewes of group B aborted,while the others were successfully delivered.In group A,the abdominal incisions of 2 lambs healed well with a line-like scar and mild intra-abdominal adhesion,and the scar thickness was 4-5 mm.In group B,the abdominal incisions of 3 lambs did not heal completely with minor intra-abdominal adhesions,and the scar thickness was 3-4 mm.The wound breaking strength was 16,20 N in group A and 10,14,and 18 N in group B,respectively.A slight scar was seen in group A;skin ulcer and underlying fibrous connective tissue with inflammatory cell infiltration were seen in group B.Conclusion It was feasible to repair the abdominal wall defect of fetal lamb at late pregnancy in uterine.Small abdominal wall defect can be sutured directly;biological patch can be used to repair larger abdominal wall defect.