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The paralysis associated with myelomeningocele: clinical and experimental data implicating a preventable spinal cord
D S Heffez1, J Aryanpur, G M Hutchins
1Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Insights
Paralysis in myelomeningocele may stem from intrauterine spinal cord injury, not just congenital defects. Protecting the exposed neural tube in utero could prevent or reduce hind limb and tail weakness in newborns.
Area of Science:
- Developmental biology
- Neuroscience
- Pediatric neurology
Background:
- Myelomeningocele is a severe birth defect affecting the spinal cord.
- Paralysis in affected children is typically attributed solely to congenital myelodysplasia.
Purpose of the Study:
- To investigate the hypothesis that intrauterine spinal cord injury contributes to paralysis in myelomeningocele.
- To test this hypothesis using a fetal rat model.
Main Methods:
- Surgically created dysraphism in fetal rats.
- Experimental group: spinal cord intentionally exposed to amniotic fluid.
- Control group: spinal cord not exposed to amniotic fluid.
Main Results:
- Experimental pups exhibited severe hind limb and tail deformity and weakness.
- Control pups were normal at birth.
- Histological examination revealed spinal cord erosion and necrosis in exposed fetuses.
Conclusions:
- Propose a "two-hit" hypothesis: congenital myelodysplasia combined with intrauterine spinal cord injury.
- Intrauterine protection of the neural tube may prevent paralysis associated with myelomeningocele.
- Findings suggest potential new therapeutic strategies for myelomeningocele treatment.
Abstract:
Paralysis seen in children with myelomeningocele has been attributed to congenital myelodysplasia. We suspected that paralysis may be due in part to a spinal cord injury caused by exposure of the neural tube to the amniotic fluid. This hypothesis was tested using a fetal rat model of surgically created dysraphism. Each pup from the experimental group of rats in which the spinal cord was intentionally exposed to the amniotic fluid was born with severe deformity and weakness of the hind limbs and tail. Control fetal rats, subjected to the same procedure without directly exposing the spinal cord to the intrauterine environment, were normal at birth. Histological studies of the exposed spinal cord revealed extensive erosion and necrosis, findings similar to those described in children with myelomeningocele. We therefore propose a "two-hit" hypothesis to explain the paralysis seen in children with myelomeningocele: congenital myelodysplasia complicated by an intrauterine spinal cord injury. Intrauterine protection of the exposed spinal cord might prevent some or all of the paralysis. The possible implications of these findings for the future treatment of myelomeningocele are discussed.