Sacral agenesis. Analysis of 22 cases.

Sacral agenesis is a rare congenital anomaly of the spine and is usually associated with urologic abnormalities. Twenty-two patients are reviewed. Twenty-one had other congenital and developmental abnormalities in addition to sacral agenesis. Physical examination showed flattening of the buttocks, loss of the gluteal cleft, widely spaced buttock dimples, and a palpable sacral defect. Lateral views of the spine are essential when anteroposterior views suggest an absence of sacral segments. Seven patients had a significant familial history of diabetes mellitus. All patients with involvement of more than one sacral segment had neurogenic bladder dysfunction with incontinence. The degree of neurologic deficit could not be predicted from the radiologic appearance of the sacrum.