Myelomeningocele: a progressive intra-uterine disease.

A series of cats were made hydrocephalic by intracisternal injection of kaolin, and four weeks later ventriculography confirmed the presence of hydromyelia. Ten days later, laminectomy in the lower thoracic region was performed. Several days later ventriculography revealed a markedly dilated central canal beneath the entire laminectomy, and pathological examination confirmed the presence of a focal bulge confined to the same region. On sectioning, it was evident that the central canal was massively enlarged to fill the entire spinal cord beneath the bulging region. The conclusion from these findings is that myelomeningocele is the result of progressive intra-uterine disease which begins with pathological hydromyelia and culminates in rupture of the unsupported spinal cord as a result of maldevelopment of associated dermal tissue.