Presentation
Paraplegia and incontinence since birth.
Patient Data
Severe hypoplasia of the L4 vertebra with absence of its posterior neural element and moderate hypoplasia of L3 and L2 vertebrae with posterior subluxation of L3 vertebra causing subsequent lumbar kyphosis and severe spinal canal narrowing.
Tethered cord ending opposite L5 vertebra with a bulky Low-lying cord segment present just caudal to the focal stenosis at L3-4.
Spinal dysraphism of L2 down to L5 vertebrae.
Severe hypoplasia of L4 with absence of its posterior neural element (yellow arrow) and moderate hypoplasia of L2 and L3 (red arrows).
The spinal cord appears low-lying and bulky just caudal to the site of spinal canal narrowing (blue arrow).
Case Discussion
Spinal segmental dysgenesis (SSD) is a rare congenital spinal anomaly in which a segment of the spine and spinal cord fails to develop normally with localized agenesis or dysgenesis of the lumbar or thoracolumbar vertebrae with congenital kyphosis. The disease is called segmental because of the presence of normal vertebrae above and below the level of segmentation.
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Diagnostic criteria include:
lumbar or thoracolumbar spinal dysgenesis or agenesis with absent or hypoplastic or dysmorphic of one or more vertebrae causing focal kyphosis
focal spinal canal narrowing with a markedly thinned or indiscernible spinal cord at this level, absent exiting nerve roots and a bulky low-lying cord segment present caudal to the focal abnormality in most cases (a unique feature for the disease)
congenital paraplegia and congenital lower limb deformity
Diagnosis is important because this rare condition does not usually benefit from surgery, unlike tethered cord syndrome.
Differential diagnosis:
Spinal segmental dysgenesis should be differentiated from cord tethering or caudal regression syndrome especially if it involves the terminal segment of the cord
It is important to distinguish between spinal segmental dysgenesis and caudal regression syndrome. This is because SSD is less likely to benefit from untethering. After all, neurological abnormalities are associated with hypoplasia or the absence of entire roots or segments of the spinal cord. Surgery may be necessary if there is spinal cord compression due to spinal abnormalities.
The case is courtesy of Dr Sally Emad and Dr Aya Sedky
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