Hypoperfusion, reversal blood flow, or aberrant vessel formation may lead to deficiencies in embryonic development. Clinical observations in humans have suggested that vascular abnormalities (disruptions or aberrant angiogenesis) may be responsible for several birth defects including defects of brachial arch derivation, gastroschisis, porencephaly, acardia, Poland, Klippel-Feil and Mobius anomalies. We report our findings using six fetal lambs that underwent fetal surgery to impede blood flow of the carotid artery and its branches, including the laryngeal artery, the anastomotic branch of vertebral artery with occipital artery, the auricularis artery and the transverse facial artery. Between 115 and 117 days of gestation, all ewes were placed under general anesthesia and provided with mechanical ventilation. We placed catheters in the femoral artery for blood gas sampling. A balloon occluder, and a blood flow probe were placed on one internal carotid while the contra lateral side was completely ligated. On the third day post surgery, the balloon occluder was inflated 3 times for 30 minutes at the time at 30 minute intervals. PO2, PCO2, pH, lactate and glucose were monitored during the study. Seven days post occlusion all animals were sacrificed and tissues were collected. Craniofacial anomalies were obvious in three animals.

Lamb 991: Hydranencephaly, small palpebral fissures with dermoid queratinization of the cornea, micrognathia, anodontia of the lower jaw, microcephaly, low set ears

Lamb 996: Severe micrognathia, tongue hypoplasia, small palpebral fissures and microcephaly

Lamb 1015: Micrognathia, maxillary hypoplasia, low set ears

Conclusion: This preliminary data suggests that late gestation vascular disruptions may lead to significant craniofacial anomalies. Some of the abnormalities seen in our animal model resemble those seen in the Hemifacial Microsomia, Goldenhar syndrome, and Pierre-Robin sequence.