Venous outflow of the brain in spina bifida aperta
Children with untreated hydrocephalus show marked distension of the veins of the skull and scalp. This is even more pronounced in children with bifida aperta. Such distension is usually relieved instantaneously when the hydrocephalus is treated by a ventriculo-cardiac drainage. This drew attention to the venous drainage of the cranial cavity and led to consideration of the possibility that impeded venous drainage might be a causalfactor in the origin of hydrocephalus. Initially, we examined brains of hydrocephalic children regardless of the cause of the hydrocephalus. After finding severe abnormalities of the cranial venous system in children with spina bifida aperta, however, we eventually confmed our investigations to these cases. This limitation had the added advantage that we were dealing with a group of hydrocephalic children with the same aetiology and representing the single most common group available. Other forms of hydrocephalus have heterogenous causes that are even less clearly understood.