Measurement of intracranial pressure via the anterior fontanelle in infants with hydrocephalus--special observations on the operative indications and pathophysiology of infantile hydrocephalus.

A miniaturized paper strain gauge transducer was developed which atraumatically and continuously monitored intracranial pressure via the arterior f ontanelle of newborn infants. Using this equiment, six infants with hydrocephalus were prospectively studied to relate the change in ICP during sleep with clinical symptoms, head circumference, ventricular size by CT-scan, CSF dynamics and development. In the first group, the pulse wave amplitude increased with age and no B-type waves were observed during non-REM sleep. These patients were observed prospectively without surgical intervention, because they seemed to have an arrested hydrocephalus. In the second group, the pulse wave amplitude was extremery low and there was little increase in amplitude with age during non-REM sleep. The frequent appearance of B-type waves was demonstrated. These patients were considered to have a compensated hydrocephalus and a V-P shunting operation was performed in both of them. In the third group, the pulse wave amplitude increased with age, and a B-type wave was frequently identified during non-REM sleep. A plateau type wave was identified with a pressure more than 250 mmH2O, approximately equal to 310 mmH2O, from the serial measurement of ICP during REM sleep. There was a progression of the ventriculomegaly and a disproportionate increase in head circumference developed. Continuous atraumatic measurement of ICP during sleep may by quite useful for assessing the reserve capacity of the intracranial space in hydrocephalic infants and for determining whether a shunt should be implanted.