Shunt and valves issues
Valve disorders on implanted patients are regularly observed. 40% of dysfunction happen within 2 years after the surgery and 98% after 10 years. The disorder can be due a dysadjustment of the valve (for models with adjustment possibility) or an obstruction of the catheter/valve set.
As soon as the cerebrospinal fluid can not be derived, the intracranial pressure is no more stabilized and hydrocephalus symptoms quickly return.