Implanted Sensor Monitors Cerebral Fluid Pressure

A novel long-term implanted sensor can measure and individually adjust cerebrospinal fluid (CSF) pressure in the brain.

Researchers at the Fraunhofer Institute for Microelectronic Circuits and Systems (IMS; Duisburg, Germany), working jointly with Christoph Miethke (Potsdam, Germany), and Aesculap (Tuttlingen, Germany) have developed a cerebral shunt and metering system that is implanted into the patient’s brain that allows physicians to read out brain pressure using a simple hand-held meter within seconds, and without complex investigation. The heart of the shunt system is a valve that releases CSF into the abdominal cavity if pressure increases above a set threshold value; once pressure declines again, the valve closes.

The device works by sending magnetic radio waves that supply the metal-encased sensor with power, thus awakening it. Once revived the sensor measures temperature and pressure of the CSF, and transmits the data back to the handheld device. If the pressure exceeds set limits, the physician can control the valve on the shunt system as needed, providing relief of accumulated CSF by releasing superfluous fluid. By measuring CSF pressure while shunting, the attending physician can avoid over-drainage and resultant lowering of cerebral pressure to a degree that could cause the cerebral ventricles to be squeezed out.

“The sensor is an active implant, which also takes over measurement functions, in contrast to a stent or a tooth implant. The sensor sets the basis for the further development through to theranostic implants,” said lead researcher Michael Görtz, PhD, head of pressure sensor technology at IMS. “In a few years, the sensor could then not only record cerebral pressure and develop a diagnosis on the basis of this but also properly adjust the pressure independently, immediately on its, own and thus take over the therapy process.”

CSF is a clear colorless bodily fluid found in the brain and spine. It is produced in the choroid plexus and acts as a cushion or buffer for the cortex, providing a basic mechanical and immunological protection to the brain inside the skull, and serves a vital function in cerebral autoregulation of cerebral blood flow. The CSF occupies the subarachnoid space and ventricular system around and inside the brain and spinal cord.

Related Links:
Fraunhofer Institute for Microelectronic Circuits and Systems
Christoph Miethke
Aesculap