Telemetric readable implant

Pressure sensor for functional analysis in the brain shunt, a discharge system used for patients with increased intracranial pressure.

Pathological excess pressure in the brain has serious consequences for the patient. When diagnosed with hydrocephalus, the brain either produces too much cerebrospinal fluid or is unable to "break it down" sufficiently. As a result, the pressure in the head increases too much, causing damage to the brain. The remedy is a shunt system that doctors implant in the patient's brain. There, it drains excess fluid into the abdominal cavity, for example.

The heart of this shunt system is a valve. The valve opens when the pressure rises above a threshold value. Until now, physicians could only prove functional control of the hydrocephalus treatment valve via costly and stressful computer or magnetic resonance imaging.This is different with a novel sensor developed by Fraunhofer IMS together with Christoph Miethke GmbH and Aesculap AG.

If the sensor is implanted with the shunt system, doctors can read out the "intracranial pressure" with a handheld reader at any time without a time-consuming examination. If the patient complains of discomfort, all the doctor has to do is hold the handheld reader up to the hydrocephalus patient's head from the outside. The device sends magnetic radio waves and supplies energy to the sensor in the shunt. The implant is "woken up," measures pressure and temperature in the cerebrospinal fluid, and sends this data back to the handheld reader.

If the measured pressure is not in the desired range, the physician can adjust the valve of the shunt system accordingly from the outside and adapt it individually to the patient.

A particular challenge that Fraunhofer IMS had to overcome in developing the sensor system was communication through the hermetic metal shell of the implant. Metal housings are a current standard to ensure the long-term stability and biocompatibility of an implant but at the same time an obstacle for electromagnetic communication.

The sensor system is CE-approved and lays the foundation for further developments towards theranostics - a neologism of therapy and diagnostics. In a few years, the sensor could not only record the intracranial pressure and assist the physician in diagnosis, but also adjust the pressure independently via the shunt system and thus actively control the patient's individual therapy.