CAUDAL REGRESSION SYNDROME - PARTIAL AND SACRAL AGENESIS
Caudal regression syndrome is a rare neural tube defect characterized by variable lumbosacral hypoplasia and/or agenesis. The associated spinal cord segments are similarly affected.
Consists variably of: absent sacral vertebrae, anal atresia, malformed genitals, neurogenic bladder, renal abnormalities and various other musculoskeletal and cardiovascular abnormalities
· Incidence: 1:7500 births; male predominence; 16% of these children have diabetic mothers.
· Imaging: if symptoms are present, 95% of patients have conus abnormalities (truncated tip, sparse cauda equina).
Plain films, CT, or MRI can be used to investigate the possibility of caudal regression syndrome. Radiographically, the sacrum, and variably the lumbar spine, is hypoplastic or absent. Frequently the iliac bones are fused at the midline. Other features of caudal regression syndrome include the possibility of prenatal diagnosis by ultrasound beginning at 22 weeks of gestation, seen as interruption of the spine and frog leg position of the lower limbs. More severely affected fetuses, such as those with sirenomelia, can be diagnosed at as early as 16 weeks. Scoliosis may be associated.
Spectrum of caudal regression (Renshaw-1978) :
- Type I: total or partial unilateral sacral agenesis.
- Type II: variable lumbar and total sacral agenesis with the ilia articulating with the sides of the lowest vertebra.
- Type III: variable lumbar and a total sacral agenesis, the caudal end-plate of the lowest vertebra resting above either fused ilia or an iliac amphiarthrosis.
- Type IV: with increasing severity, soft tissues of both the lower limbs are fused. They have two femora and two tibiae with a single central fibula between the two tibiae.
- Type V: is also known as \"serinomelia\" or \"mermaid syndrome\" wherein there is a single femur and tibia.