Abstract: To observe the changes of pre and postventriculoperitoneal shunt and shuntocclusion on brain compliance in hydrocephalus by using a canine model of obstructive hydrocephalus. Methods： Eighteen adult healthy mongrel dogs, twelve in which was as hydrocephalus models and six as controls, were used in the experiment. Eight weeks after inducement of hydrocephalus, intracranial pressure (ICP) and brain compliance at low (515?mmHg) and high (1525?mmHg) pressure were measured. Following this procedure, ventriculoperitoneal shunts were implanted in all dogs. Two weeks later, the same measurements were repeated, and the shunt systems were occluded. The last measurements were obtained after one week. All dogs underwent magnetic resonance imaging four times before inducement of hydrocephalus and before each measurement. Results: In the experimental group, hydrocephalus confirmed by MRI was successfully induced in ten dogs. ICP of hydrocephalus dogs（9.98±1.84?mmHg）was significantly higher than that in control group（3.82±1.19?mmHg，　P<0.01）. After shunt placement, significant improvement was observed in their hydrocephalus symptoms and in ICP （4.28±1.25?mmHg，P>0.05）. However, shunt occlusion reversed these improvements quickly to the preshunt status and carried a risk of critical symptoms poor outcomes. Brain compliance measured at high pressure demonstrated a significant gradual decrease at each measurement. Conclusions： The canine model of obstructive hydrocephalus should facilitate the study of the pathophysiology and the treatment of hydrocephalus. The decrease in brain compliance may be one of the factors responsible for the acute pathological changes after thefailure of shunt in hydrocephalus.

Key words: Hydrocephalus, Dog, Compliance, Magnetic resonance imaging