Body Stalk Anomalies in Pigs: Current Trends and Future Directions in Classification.

Body stalk anomaly (BSA) is a complex congenital condition characterized by defects in the body wall, skeletal abnormalities, and an absent or abnormal umbilical cord (UC). A classification system for BSA, based on wall and skeletal abnormalities, is proposed and includes eight types observed in porcine models. These classifications consider combinations of thoracoabdominoschisis, abdominoschisis, anal atresia, genitourinary anomalies, and skeletal defects, including extreme retroflexion, scoliosis, vertebral agenesis, hemivertebrae, and thoracic or limb anomalies. While previous studies often treat limb-body wall complex (LBWC) as a separate condition, this study includes cases with co-occurring limb and spinal defects in a new classification, spinal-limb-body wall complex (SPLBWC). Additional skeletal classifications-spine-body wall complex (SPBWC), sternal-body wall complex (STBWC), and sternal-spinal-body wall complex (SSBWC)-are introduced to account for variations in structural anomalies. Nonstructural skeletal anomalies such as deformities, amputations, and arthrogryposis are excluded from the structural classifications. This comprehensive system, based on existing human and porcine models, provides a framework for the systematic categorization of BSA variations. Such an approach supports accurate diagnosis, enhances understanding of developmental defects, and improves clinical management and research outcomes in both veterinary and human medicine.