What Is the Right Pressure of Shunt Valves in Newborns?

Background: Hydrocephalus in newborns is treated by ventriculo-peritoneal shunting with a pressure valve. According to the literature, the normal intracranial pressure in newborns amounts to 0 to 5 cm H₂O. Low-pressure valves can result in overdrainage, leading to hygromas, slit ventricle syndrome, or craniosynostosis. High-pressure valves can result in underdrainage, leading to ventriculomegaly or brain atrophy. Fixed pressure valves are usually very small in size but require valve replacement for each adjustment. Adjustable valves are larger, but allow noninvasive pressure changes. We will show that half of the newborns will require valve adjustments.

Methods: Twenty-five newborns within a 2-year period were implanted with the Aesculap-Miethke-proGAV-Shunt system, consisting of an adjustable differential pressure valve, range 0 to 20 cm H₂O and a 20 cm H₂O gravity-dependent valve. Valve pressure, percentile distribution of head circumference, and body length were documented; ventricle size was estimated through transfontanel sonography. Criteria for valve adjustments were significant drops or rises in the head circumference percentile or ventricle size.

Results: The mean initial adjusted pressure was 5.9 cm H₂O (95% CI: 6.6/5.1). Overall 18 adjustments in 10 out of 25 children (56%) were performed. In children, in whom the valve had to be upregulated, the mean pressure amounted to 7.7 cm H₂O (95% CI: 8.6/6.7). In children, in whom the valve had to be downregulated, the mean pressure amounted to 2.0 cm H₂O (95% CI: 3.8/0.2). The differences between the three groups were significant (p < 0.05). There was no morbidity associated with the large valve size.

Conclusion: The proGAV valve was readjusted in more than half of the newborn children.