The Development and Validation of a Portable, Benchtop, Hydrostatic Model to Acquire and Analyze Quantitative Data on Unused and Failed Hydrocephalus Catheters

IntroductionDespite the prevalence of shunt failure in the treatment of hydrocephalus and the near-constant need for shunt revisions, there are a limited number of methods that yield quick, quantifiable measures of catheter obstruction. We developed and assessed a gravity-driven device that measures flow through ventricular catheters. The model provides neurosurgeons with a quick, simple device that can send useful data to researchers. It can also be used by researchers to quantitatively compare catheter obstruction between different models of catheters. The model was used in this study to quantitatively analyze unused ventricular catheters used in the treatment of hydrocephalus; failed hydrocephalus catheters from our catheter biorepository were also quantitatively analyzed using the same device. The mechanisms of catheter obstruction are still poorly understood, but the literature suggests that resistance to fluid flow plays a significant role. MethodsCatheters of three manufacturing companies were inserted into the benchtop model, which records time, flow rate, and pressure data using sensors. The relative resistances of catheters across six design models were evaluated. Experiments were performed to evaluate changes in the relative resistance of a catheter when the catheters holes were progressively closed. Relative resistance of explanted catheters from our catheter biorepository was also measured. ResultsExperimental results showed significant differences (P < 0.05) between the relative resistances of different catheter models just after being removed from their packaging. Furthermore, a trend of increasing resistance was observed in the experiments on catheters with manually plugged ventricular catheter holes. Data from five individual benchtop models were compared, and the differences in measured data between the models were found to be negligible. A significant increase (P < 0.05) in relative resistance was observed in explanted catheters. ConclusionThe current study is meant both to validate the proposed model and to examine data on differences in relative resistance among catheter models. From these experiments, we can rapidly correlate clinical patient cohorts to identify mechanisms of luminal shunt obstruction. Collecting data for predictive analyses of potential patient outcomes is an area of potential future work, assuming sufficient sample size.