Experimental Induction of Complex Gastroschisis in the Fetal Lamb: Systematic Review

We systematically reviewed experiments in the fetal lamb model of gastroschisis using PubMed, Embase, Web of Science, and Scopus, seeking for standardized surgical techniques to obtain complex gastroschisis. Eligible were studies where an abdominal wall defect was surgically induced and gross anatomical findings at birth were available. The primary outcome was complex gastroschisis, defined by the presence of bowel stenosis, atresia, volvulus, perforation, and/or necrosis. Secondary outcomes were fetal death and additional readouts reported. Of ten eligible studies, six included lambs that had no additional prenatal manipulations and were assessed at term (35 lambs). Gastroschisis was induced at day 70-80 (term = 140-145), typically (n = 4/6 studies) in the left lower abdomen with defect size ranging from 0.5 to 4.0 cm. Only one study, in which a 1.5 cm diameter silicone ring was utilized, resulted in complex gastroschisis in 100% of term survivors. Fetal loss was more frequent in studies where a silicone ring and/or a right-sided defect were used. No changes unique to complex gastroschisis were identified in additional readouts, including bowel histology. When gastroschisis becomes "complex" following induction is uncertain. This knowledge is essential in studying potential prenatal interventions that may change the natural course.