A computational model of the cerebrospinal fluid system incorporating lumped-parameter cranial compartment and one-dimensional distributed spinal compartment

The dynamic transmission of pressure through the cerebro-circulatory system may play a role in the genesis of pathological conditions of the brain and spinal cord. This study aims to lay down the foundations for computer modelling of the cerebrospinal (CSF) pressure dynamics in the cranio-spinal cavity as a single entity. The cerebro-vascular system was modelled as a set of resistors and capacitors. The model of the CSF space comprised a lumped cranial compartment and a distributed spinal compartment. Apart from simulating normal (baseline) conditions, the effects of jugular vein compression, and thoracic pressure elevation by coughing were investigated by applying pressure waveforms at the appropriate points in the model. The Chiari malformation was simulated by assigning high resistance to the circulation of the CSF between the cranium and the spine. The model was capable of reproducing physiologically plausible results for all forms of excitation. The spinal cavity behaved effectively as a lumped compartment, except for the cough excitation where wave-type behaviour was evident. In that case, the Chiari obstruction resulted in prolonged periodic straining of the spinal cord. This result can be of significance for understanding the mechanism of the formation of cysts in the spinal cord.