New Spinal Implant Could Revolutionize Physical Therapy

A new implantable microchip the size of a child’s fingernail can help the disabled exercise their leg muscles. The Active Book chip shows potential to replace traditional electrodes in moving immobile legs for physical therapy.

Active Book microchip

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

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


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