Computer modelling has been undertaken to determine the resistance to flow
in the subarachnoid space (SAS) and to investigate its contribution to the
total pressure drop. A Computational Fluid Dynamics model has been used to
determine the pressure drop as a function of both the flow rate and the per
meability of the subarachnoid space. The conclusion is that the SAS contrib
utes about 1-5% of the total CSF flow resistance. However, scarring of the
arachnoid fibres could increase the flow resistance considerably. (C) 1999
Harcourt Publishers Ltd.