COMPUTER MODELING OF SIPHONING FOR CSF SHUNT DESIGN EVALUATION

A computer model of the cerebrospinal fluid (CSF) compartment and vari ous shunt designs was developed to simulate CSF dynamics, particularly in the upright position in which siphoning is known to occur. This no vel mathematical model of the CSF compartment incorporates negative pr essure and volume components that permit simulation of siphoning. The model was tested with data from a previously reported animal experimen t. The correspondence between the model simulation and the reported in tracranial pressure and CSF shunt flow rate was very good. A simulatio n of a shunted hydrocephalic patient in the recumbent and upright posi tion was then carried out to examine the effects of a standard shunt v alve, an externally adjustable valve, a variable resistance valve, and an antisiphon device. The resulting pressure profiles, which conforme d to previously reported data, indicate that this model would be usefu l for the evaluation of current and future shunt designs.