Sacral Agenesis and Caudal Regression Syndrome

Sacral agenesis is a term applied to a group of disorders in which a portion of the caudal spine does not form. It is rare with its incidence between one in 20-30,000 live births. It can occur as a part of Caudal Regression Syndrome where there is often an associated neural tube defect.

The spinal cord is always involved leading to motor as well as sensory problems. Key clinical diagnostic features include incontinence, lower limb contractures and associated spine curvature defect. The Renshaw classification is used to characterize the severity of the defect. Grade I is the mildest with only unilateral sacral agenesis and grade IV has partial lumbar and total sacral agenesis with fused iliac bones.