A Revolutionary Microchip

December 8th, 2010 by Neil Ungerleider

The Active Book spinal implant promises big advancements in physical therapy.

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A new implantable microchip the size of a child's fingernail has been proven to help the disabled exercise their leg muscles. The Active Book chip, developed in Britain, could just replace the use of electrodes for moving immobile legs in physical therapy.

The chip is implanted in patients' spinal canals and integrates electrodes and a muscle stimulator into a single, tiny unit. Developers named the product the Active Book due to the implant's shape: The Active Book consists of a silicon chip attached to tiny electrodes made out of platinum foil that then wrap around patient's nerve endings. Viewed with a microscope, the effect looks quite like the pages of a book are folded over the nerve endings.

While previous attempts at muscle-stimulating spinal implants have been tried before, the vast majority have been bulky and difficult to implement in real-world situations. The Active Book's small size means that it will be far easier to implant into users' spines.

According to Dr. Andreas Demosthenous of University College London, who is the leader of the research team that developed the Active Book, “The work has the potential to stimulate more muscle groups than is currently possible with existing technology because a number of these devices can be implanted into the spinal canal […] Stimulation of more muscle groups means users can perform enough movement to carry out controlled exercise such as cycling or rowing.”

Other possible uses for the implant include the possibility of using multiple implants in one patient to help the disabled with restoration of bladder or bowel control. The size of previous implants meant that doctors and surgeons were uncomfortable with inserting more than one into a patient. Infection and hygiene concerns also surround current spinal implants.

The bulkiness reduction in the new implant is significant and praiseworthy: Current implants that stimulate spinal nerves have to be connected via cable to an outside power source, which usually consists of a muscle stimulator separately implanted in the user's abdomen. This is the first spinal implant that also includes a muscle stimulator. Apart from the size reduction, this also means better results are likely.

Demosthenous' team at University College London developed the Active Book along with engineers from Germany's Freiburg University and the University of Cork in Ireland. The implant was developed over the past three years with funding by the British Engineering and Physical Sciences Research Council (EPSRC).

The silicon microchip used in the implant is hermetically sealed to prevent water penetration and any possible corrosion.

Pilot testing of the implant will begin in 2011. Further details on the tests were not available as of press time.