I. Introduction
Intracranial hypertension (IH) is a neurological complication which is commonly observed following severe traumatic brain injury (TBI), disturbances of CSF flow, and idiopathic IH [1]. Treatment of elevated ICP through a variety of interventions is believed to prevent secondary brain damage. In clinical settings, the placement of an intraventricular catheter and fluid-coupled measurement of ICP is considered the gold standard [2]. There are alternative devices that consist of fiber-optic catheter-tip pressure transducers that can be inserted into the ventricle or brain parenchyma to measure ICP. These devices by themselves do not allow CSF drainage. However, both methods are time-limited, and require a direct connection through the scalp to an external device. In addition, the insertion of a ventricular catheter carries the potential risk of infection and intracranial hemorrhage [3], [4]. In patients with hydrocephalus, treatment often requires the placement of a shunt to divert excessive CSF from the brain to the peritoneal cavity (a ventriculo-peritoneal, or VP shunt). The common problems with VP shunts are obstruction, mechanical failure and over/under drainage [5]. Direct measurement of ICP with most shunt systems is impossible. To detect these complications, implantable intraventricular ICP sensors can be introduced along with the shunt systems to continuously monitor their function.