Caudal regression syndrome type I

Case contributed by Cody Sutphin
Diagnosis almost certain


Hypotonic, apneic preterm newborn with right club foot and small lower extremities

Patient Data

Age: 31 week newborn
Gender: Female

Initial babygram showed 4 lumbar-type vertebral bodies with L5 not definitely identified and no ossified sacral vertebral bodies observed.


Ultrasound performed for evaluation of caudal regression syndrome following babygram revealed blunted conus medullar is ending at superior L1 level and 4 lumbar type vertebral bodies.

Follow up sagittal T2 MRI of lumbar spine without IV contrast revealed absent/markedly regressed sacrum with a truncated conus medullar is terminating at L1.

Case Discussion

Caudal regression syndrome is a rare anomaly of the pediatric spine. It has an increased frequency in diabetic mothers and can be observed alongside VACTERL or OEIS abnormalities and the currarino triad. Family history also plays a role in acquiring the disorder2.

Clinical presentation includes hypotonia, small or even fused lower extremities, foot deformities and GI/GU abnormalities3.

Type I caudal regression has a blunted cord at level L1 or higher and more severe distal osseous anomalies. Type II has a more distal, tapered cord that is tethered by a thickened filum or intraspinal lipoma. Neurologic deficits are more common amongst type II with a more distal tethered cord1.

Plain films can help identify osseous abnormalities in these individuals and ultrasound can be used to further evaluate the spinal cord, but MRI is considered the best modality to evaluate for caudal regression syndrome and comorbid findings1.

The presence of a blunted conus at L1 and a severely regressed or absent sacrum suggests caudal regression syndrome type I in this patient.

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