Too Much Pressure: Wireless Intracranial Pressure Monitoring and Its Application in Traumatic Brain Injuries

Intracranial pressure (ICP) is the pressure exerted by the components of the cranial vault, which are the brain, cerebrospinal fluid (CSF), and blood. An elevation of ICP results in a reduction of blood flow to the brain [1]. The brain can cope with intracranial hypertension (ICH) to a certain extent, after which a slight increase in the cerebral volume results in a rapid rise of ICP [2]. A significant reason for death and long-term disability due to head injuries and pathological conditions is an elevation in ICP. An ICP > 20 mmHg is considered a significant threshold and demands an immediate control measure [3]. ICP monitoring can assist in the management of patients with a variety of brain diseases and injuries. The technique has proven valuable, indeed often lifesaving, in the acute care of traumatic brain injury (TBI) [4], hydrocephalus [5], drowning [6], inflammatory and related cerebral diseases such as Reye?s syndrome [7], intracranial hemorrhage [8], and postoperative suboccipital brain tumors [9]. Most patients have headaches and other symptoms suggestive (but not always indicative) of raised ICP; continuous access to ICP levels would greatly facilitate their management. There is a conspicuous need for a wireless implantable ICP-monitoring system as several chronic diseases are associated with ICH. Accurate monitoring of the ICP following a neurosurgical procedure is a basic requirement for adequate treatment [10]?[12]. Since the intracranial contents exist within a rigid vault (the skull), direct ICP measurements require neurosurgical intervention, with its attendant risks. An implant placed during surgery, for the underlying cause of neural disorder, would be a useful adjunct to patient care.