To shunt or not to shunt: hydrocephalus and dysraphism.

Objective criteria are available for decision making in children with ventriculomegaly and spina bifida cystica. Figure 29.7 is the evaluation algorithm used in the Hydrocephalus/Myelodysplasia Clinic at Rainbow Babies and Children's Hospital. In children without serious neurosurgical complications such as the Chiari crisis or problems with wound healing, we rely on three reasonably objective measurements for decision making. Head circumference: Measured daily while in hospital and at each visit. If the pattern of head growth crosses multiple percentile lines indicating that the child will be severely megalencephalic, a shunt will be performed. Ultrasonography: Ultrasound determinations are made in the first few days of life, prior to discharge, at 6 weeks of age, and each 6 weeks of age until 6 months. Some measurements of ventricular size (usually CT scan because of a small anterior fontanelle) should be made at age 1 year. Denver Developmental Testing (DDST): These are performed at age 6 weeks and each 6 weeks thereafter. If the child shows significant ventriculomegaly, a shunt is performed. When the results are questionable the decision is delayed and the test repeated in 6 weeks. Whether a shunt is or is not placed in an infant with ventriculomegaly and myelodysplasia, follow-up must remain compulsive. Following shunting, not only should the head circumference stabilize, but the cortical mantle should increase. Often children shunted in this situation fail to show signs of increased intracranial pressure with shunt malfunction and must be followed with serial head circumference measurements as well as ultrasounds and CT scans. If the decision is made not to shunt the child the work of Hall et al. (10) would suggest the possibility that later in life shunts may be needed to prevent scoliosis secondary to hydromyelia. More information is needed as the aggressively treated population become adults.