Wireless, non-battery intracranial sensors

Departments - Small world

Integrated Sensing Systems Inc. (ISSYS) has developed a wireless medical product to monitor intracranial pressure.

April 15, 2010

ISSYS catheter pressure sensors show how miniature technology is getting, just like the ISSYS intracranial sensors.Integrated Sensing Systems Inc. (ISSYS) has developed a wireless medical product to monitor intracranial pressure. One of the most important intracranial applications is monitoring of shunt pressure for the long-term management of hydrocephalus.

Hydrocephalus refers to an imba­lance between the production and ab­sorption of cerebrospinal fluid within the ventricular system of the brain. Affecting nearly 1.3 million patients in the U.S. alone, hydrocephalus is treated for the patient’s lifetime. Treat­ment usually is accomplished with a shunting system that diverts the flow of CSF from a site within the central nervous system to another area of the body where it can be absorbed as part of the circulatory process.

Unfortunately, shunts are far from fail-safe; a full 40% of VP shunts fail within the first year of placement, and 5% fail per year after the first year. On average, hydrocephalus sufferers need to have their shunts surgically replaced every six years, with some needing replacements far more frequently. Shunts can over drain and/or become clogged, causing discomfort, injury, or even death to a patient if not corrected. Currently, the only methods for evaluating intracranial pressure (ICP) are MRI or CT scans, which are costly, time-consuming, and not readily accessible on short notice. Furthermore, symptoms of shunt malfunction often include general moodiness and/or headaches.

By detecting blockage, over drain­age, and normal shunt pressures, ISSYS’ shunt monitor will minimize misdiagnoses and unnecessary replacement surgeries; reduce the number of neurologist visits, CAT scans and MRIs to diagnose shunt malfunction; and alleviate the uncertainty and emotional distress associated with shunt misfunction. Based on conservative estimates, this technology has the potential to save nearly $1.3 billion per year in testing for the U.S. economy alone.

Technology, Solution
ISSYS wireless pressure techno­logy has the ability to provide safe, continuous intra­cranial pressure measurements, with the potential to revolutionize the way hydrocephalic and brain trauma patients are treated. The system consists of two major parts: an implantable, batteryless, telemetric sensor and a companion hand-held reader. The miniature implantable micro-device contains a MEMS (MicroElectroMechanical System) pressure transducer along with custom electronics and a telemetry antenna. Using magnetic telemetry, the reader transmits power to the sensor and the sensed pressure is, in turn, transmitted back to the reader. Data collected by the sensor will be used by physicians to monitor brain pressure. For long-term hydrocephalous patients, data collection can be performed at the doctor’s office or at home by the patient and then submitted over the telephone or internet.

One important need the system meets is that it also monitors the performance of the shunt. The ICP monitor can detect blockages, over drainage, and normal pressures using the hand-held readout unit. It will then alert patients, parents, and practitioners to potential shunt failure, mitigating the uncertainty of present systems, reducing the risk of damage due to delays from misdiagnoses, and reducing the need for expensive testing procedures. A conventional shunt system that has been augmented with the proposed sensor can be implanted by a neurosurgeon using standard surgical procedures.

In short, the shunt monitor will:

  • Facilitate timely recognition of shunt failure;
  • Eliminate uncertainty regarding shunt function, permitting more accurate diagnoses;
  • Permit home monitoring, eliminating costly physician visits, CAT scans, and MRIs; and
  • Lower overall treatment costs while improving disease management.

Integrated Sensing Systems Inc.
Ypsilanti, MI