Proximal ventricular shunt catheter occlusion model.

PURPOSE: Proximal ventricular shunt catheter occlusion remains a problematic cause of shunt malfunction, and there is no consistent in vivo or in vitro model to help clinicians and researchers study this phenomenon.

METHODS

An in vitro model utilizing standard proximal ventricular catheter and biological occluding agents mimicking choroid plexus was designed, constructed, and calibrated to occlude consistently within a specified timeframe. Hydrostatic pressure differential of 100 cmH2O was used as a driving force to generate flow through the catheter. Chalaza and vitelline membranes were harvested from avian eggs and used as occluding agents. Successful occlusion was defined as a greater than 90% reduction in volumetric flow rate through distal outlet. Histological sections of occluded catheters were performed and interpreted by a neuropathologist.

RESULTS

Initial trials demonstrated successful standard catheter occlusion within 24 h using chalaza, vitelline membrane, and combination treatments. Repeat trials demonstrated consistency in successful occlusion within 5 min utilizing only vitelline membrane treatment. Histopathology demonstrated the vitelline membrane to consist of a thin, superficial layer of extraembryonic ectoderm; the chalaza was observed to consist of strands of mucin protein.

CONCLUSIONS

An in vitro model of proximal ventricular shunt catheter occlusion was developed and calibrated for successful occlusion within 5 min. Future studies may utilize this model to rapidly test occlusion-resistant shunt designs and de-obstruction techniques.