Hydrocephalus in myelomeningocele.

156 children born with myelomeningocele were studied over a 3- to 10-year follow-up period. The appearance, type and rate of development of hydrocephalus were noted and correlated with the findings on neonatal and follow-up physical examination. 80% of the children developed overt hydrocephalus; 73.4% of these cases were secondary to aqueductal stenosis. Only 15.3% of the cases showed physical evidence of hydrocephalus at birth. Another 64.8% of the children developed clinical signs of hydrocephalus during the follow-up period, most during the first few weeks but some as late as the third year of life. The neonatal examination is unable to predict the subsequent appearance of hydrocephalus or its rate of development, and even serial determinations of head circumference are often of limited value. The authors conclude that the early diagnosis of hydrocephalus in children with myelomeningocele cannot reliably be made on physical examination alone and that other means of assessing ventricular size should be employed.