Caudal regression syndrome: etiopathogenesis, prenatal diagnosis, and perinatal management.

Caudal regression syndrome represents a continuum of congenital malformations ranging from agenesis of the lumbosacral spine to the most severe cases of sirenomelia with lower extremities fusion and major visceral anomalies. The etiology of this syndrome is not well known. Maternal diabetes, genetic predisposition, and vascular hypoperfusion have been suggested as possible causative factors. The degree of associated anomalies usually parallels the severity of the primary defect. Ultrasonography is the diagnostic tool of choice revealing the absent distal vertebrae of the fetal spine. Amnioinfusion and magnetic resonance imaging (MRI) are of help in better evaluation of the fetal anatomy in cases with oligohydramnios. Perinatal management depends mainly on gestational age at diagnosis and severity of the lesion. It should include genetic counseling and serial sonography to assess interval growth and amniotic fluid volume. Surviving infants have usually a normal mental function and they require extensive urologic and orthopedic assistance. Their long-term morbidity consists mostly of neurogenic bladder dysfunction resulting in progressive renal damage and disabling neuromuscular deficits of the lower extremities. Neurosurgical and orthopedic intervention with physical rehabilitation is indicated to improve the quality of their lives.