summary Sacral Agenesis is a congenital condition associated with caudal regression syndrome characterized by the partial or complete absence of sacrum and lower lumbar spine. Diagnosis is made clinically with prominence of the last vertebral segment and postural abnormalities. Treatment involves a multidisciplinary approach to address neurological, genitoturinary, and orthopedic manifestations Epidemiology Incidence 1 - 2.5 per 100,000 newborns Risk factors highly associated with maternal diabetes Etiology Pathophysiology neurologic involvement motor deficit corresponds to level protective sensation is usually intact important in that there is a lesser rate of decubiti ulcers this differentiate from myelodysplasia Associated conditions caudal regression syndrome gastrointestinal disorders (imperforate anus) genitourinary disorders cardiovascular disorders lower extremity deformities progressive kyphosis Classification Renshaw Classification Type I Partial or total unilateral sacral agenesis Type II Partial sacral agenesis with a bilaterally symmetrical defect Type III Ilium articulating with the sides of the lowest vertebra present Type IV Caudal endplate of vertebra resting above fused ilia or an iliac amphiarthrosis Presentation Symptoms clinical presentation is based on the severity of disease Physical exam inspection prominence of the last vertebral segment classic sign of buttock dimping postural abnormalities (e.g. sitting buddha) limb and joint contractures extended knees, flexed hips, and equinovarus feet. motion flexion and extension may occur at the junction of the spine rather than hips neurovascular examination motor and sensory deficits are common in severe disease Treatment Nonoperative physical therapy indications Renshaw type 1/2 outcomes most become community ambulators foot and knee deformities to be addressed Operative spinal stabilization procedures indications Renshaw type 3/4 with progressive kyphosis or scoliosis outcomes progressive kyphosis and/or scoliosis may develop between the spine and pelvis child must use his or her hands to support the trunk, and therefore is unable to use his or her hands for other activities limb amputation indication non-fuctional lower limb deformities outcomes better mobility Complications