Non-linear intracranial dynamics of shunt siphoning

Siphoning is commonly associated with shunts, a treatment used in patients suffering from Hydrocephalus. Siphoning is known to have a negative effect on intracranial dynamics. In this paper, a model will be developed for the intracranial dynamics in the presence of siphoning based on the assumption of pulsatile intracranial dynamics as a forced non-linear van der Pol oscillator. This non-linear model is used to simulate how various degrees of siphoning can effect intracranial dynamics and create an understanding of painful side effects, such as vascular headaches. The model suggests that vascular headaches are due to an increase in the amplitude of arterial pulsations caused by the force exerted on the cranium by siphoning rather than due to volume shifts of cerebrospinal fluid (CSF).