This work was carried out locally at our department, and highlights the continuing need for research in understanding basic physiological principles in intracranial pressure regulation.
ObjectCurrent published normal values for the intracranial pressure (ICP) are extrapolated from lumbar cerebrospinal fluid pressure measurements, and intracranial ICP measurements in patients treated for cerebrospinal fluid pressure disorders. There is an emerging agreement that true normal values are needed for diagnostic and therapeutic purposes. This study documents the normal intracranial pressure in man.
MethodsIn this study we included adult patients scheduled for complete removal of a solitary clearly demarcated small brain tumor. Mean age 67 (range 58–85). Exclusion criteria seek to create a study population with as normal a brain as possible. A new telemetric ICP monitoring device was implanted at the end of surgery and monitoring conducted two and four weeks post-operatively.
ResultsIn the supine position, mean ICP was 0.5 mmHg (SD, 4.0). Postural change to the standing position resulted in a decrease in ICP to mean –3.7 mmHg (SD, 3.8)). Our results show ICP to be considerably lower than previously estimated.
ConclusionsWe provide a preliminary reference range for the normal intracranial pressure in man. It is the first study to show that ICP in the healthy human brain decreases to negative values when assuming the upright position. If these results are later confirmed in a larger series, this may provide reference values for diagnosis and treatment in patients with CSF related disorders. New normal values also have implications for future shunt design and the ICP target range in hydrocephalus treatment.
Read the full paper in Journal of Neurosurgery (click here).