[Efficacy and some complications of programmable pressure valve]

Twenty-five patients with hydrocephalus were treated using Sophy programmable pressure valve. The valve pressure is adjustable percutaneously with a magnet. This valve was very useful for management cases presenting overdrainage and high-risk cases of shunt dysfunction such as aqueductal stenosis and idiopathic normal pressure hydrocephalus. It was also useful for hydrocephalus after subarachnoid hemorrhage because it was difficult to know the most adequate pressure before the shunt operation. Two patients developed acute subdural hematoma of arterial origin after the shunt operation. The causative factor appeared to be low intracranial pressure and rupture of small arterial branches. This complication may be more frequent in cases using this system than in cases using other systems. We must pay attention to this complication and it is necessary to improve the shunt system. One bed-ridden patient developed necrosis of the skin because of this valve, and it had to be removed. We should place this valve so that it is at the anterior of the chest.