Heffez D S, Aryanpur J, Hutchins G M, Freeman J M
Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Neurosurgery. 1990 Jun;26(6):987-92.
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.
脊髓脊膜膨出患儿出现的瘫痪一直被归因于先天性脊髓发育不良。我们怀疑瘫痪可能部分是由于神经管暴露于羊水导致的脊髓损伤。使用手术造成脊柱裂的胎鼠模型对这一假设进行了验证。实验组的每只幼鼠，其脊髓被故意暴露于羊水中，出生时均伴有严重的后肢和尾巴畸形及无力。对照组的胎鼠接受相同手术，但未将脊髓直接暴露于子宫内环境，出生时正常。对暴露脊髓的组织学研究显示广泛的侵蚀和坏死，这一发现与脊髓脊膜膨出患儿中描述的情况相似。因此，我们提出一个“两次打击”假说来解释脊髓脊膜膨出患儿出现的瘫痪：先天性脊髓发育不良并发子宫内脊髓损伤。对暴露脊髓进行子宫内保护可能预防部分或全部瘫痪。讨论了这些发现对脊髓脊膜膨出未来治疗的可能影响。
