In 21 children with myelomeningocele who underwent kyphectomy for congenital kyphosis of the lumbar spine, aortography revealed no case in which the aorta followed the spinal curvature. Many anomalies of the intercostal and segmental arteries were demonstrated which were only in part associated with deformities of the respective vertebral bodies. The kidneys, which were frequently malformed, often lay within the kyphosis and were therefore at risk of operative damage. We conclude that the aorta is not at risk and that aortography is not usually necessary before kyphectomy, except in patients who have undergone prior abdominal surgery. Non-invasive methods (ultrasound, CT or MRI) should be used to detect malpositions and malformations of the kidneys.