Association of congenital anomalies of the spine and kidneys.

Specific congenital malformations of the spine are consistently associated with characteristic types of urinary tract malformation. Patients with defects of the spine such as spina bifida occulta, partial or complete absence of the sacrum, unilateral or bilateral failure of segmentation, and wedged vertebrae are not usually associated with congenital urinary tract malformations. Spina bifida and myelomeningocele have a low incidence of urinary tract abnormalities (2.1% in this study). If there are other spine abnormalities associated with spina bifida, the incidence or urinary abnormalities increase 10 times. However, hemivertebrae occurring alone in patients or occurring in conjunction with other anomalies of the spine, are most frequently associated with urinary tract abnormalities (66%). Hemivertebrae of the low cervical and upper thoracic spine carries the highest incidence of associated urinary tract malformation.