Case study of relevant pressures for an implanted hydrocephalus valve in everyday life

Hydrocephalus patients with increased intracranial pressure are generally treated by draining cerebrospinal fluid (CSF) into the abdomen through an implanted shunt with a passive differential pressure valve. To perfectly adapt the valve´s opening pressure to the patient´s need, more information on the acutal pressure across the valve in everyday life actions like walking, eating, sleeping etc. is necessary. Therefore, intracranial pressure (ICP), intra-abdominal pressure (IAP) and the hydrostatic pressure between both ends of the the fictitious shunt have been measured simultaneously for up to 24 hours in home environment at different body postures. The patient was wearing the new telemetric ICP probe Neurovent-P-tel as implant. The pressure sensor Omnibar E5F measured IAP in the rectum (10 cm deep). In this pilot study, IAP increased 20 mmHg more than ICP during coughing and 35 mmHg more during sneezing. As the pressure difference across the fictitious valve became negative in some postures, CSF drainage would not have been possible. To the authors´ knowledge, this is the first paper that presents measurements, which provide insight into the differential pressure across a hydrocephalus valve in everyday life and give information for future electromechanic shunts development.