A new experimental model of obstructive hydrocephalus in the rat: the micro-balloon technique

We used three types of specialized micro-balloons 0.7-1.35 mm in outer diam eter instead of kaolin to develop a reproducible rat model of hydrocephalus with a low experimental mortality. The micro-balloon was inserted 6 mm dee p into the cisterna magna via a burr hole immediately behind the lambda. Th e angle of introduction was 50 degrees. We also set up kaolin-induced hydro cephalic models in 25 rats as controls. The kaolin model revealed 52% morta lity with an 80% induction rate of hydrocephalus, while the balloon model s howed 9% mortality with a 60% induction rate. Balloon-induced hydrocephalus was maximal at 1 week and tended to decrease after 2-3 weeks. The patholog ical findings were not different between the two models. We concluded that the micro-balloon model for hydrocephalus is an easily reproducible model w ith low experimental mortality.