Pulsating plaster stuck to the back of the knee to beat killer blood clots
01:23 GMT, 18 December 2012
A high-tech plaster that’s stuck to the back of the knee could lower the risk of deep vein thrombosis (DVT) or blood clots in the leg following surgery.
The plaster generates electronic pulses that stimulate a nerve, the common peroneal nerve, in the back of the knee.
This nerve is responsible for making muscles in the calf, shin and foot contract.
Once the Geko has been turned on, the nerve sends signals to the muscles deep in the leg, causing them to contract every few seconds
/12/18/article-2249638-006E688C00000258-229_468x300.jpg” width=”468″ height=”300″ alt=”Deep vein thrombosis (DVT) is a blood clot in a vein, usually in the leg. It's most commonly associated with immobility, such as on a long-haul flights ” class=”blkBorder” />
Deep vein thrombosis (DVT) is a blood clot in a vein, usually in the leg. It's most commonly associated with immobility, such as on a long-haul flights
It looks like a cross between a watch and a plaster.
The larger ‘watch’ part at one end houses a power unit, battery and an on/off button.
The power unit is connected to two electrodes, which run the length of the strap.
To use the device, a doctor peels off a protective strip to reveal a sticky gel, which not only helps fix the device to the back of the knee but also helps conduct the electrical pulses through the skin to the peroneal nerve.
Once the Geko has been turned on, the nerve sends signals to the muscles deep in the leg, causing them to contract every few seconds.
They squeeze the blood vessels and blood is pumped back up towards the heart, instead of lying still in the lower leg. Doctors can tell if the power is sufficient because the calf and foot visibly twitch when the muscles contract.
The patient feels the muscles twitching but there is no pain.
In a study at St Bartholomew’s involving 30 healthy patients, there was a 25-fold increase in the speed at which blood flowed through the lower legs when the device was stuck behind their knees.
Professor Beverley Hunt, medical director for the charity Lifeblood, which campaigns for greater awareness of the risks of DVTs, said the Geko device was an ‘interesting approach’ but there was not enough clinical data to show it was any better at reducing clots than existing therapies.
‘It can increase blood flow through the leg, but that does not automatically mean it will translate into fewer DVTs.
'I would like to see a study of around 5,000 people, and where they look at the rate of DVTs.’
Meanwhile, the technique of targeting nerves with electric pulses is being used to tackle rheumatoid arthritis, a condition caused when cells of the immune system mistakenly attack the tissue of the joints.
Recent studies suggest this is partly co-ordinated by the vagus nerve.
This is one of the longest nerves in the body, running from the brain to the base of the spine.
Small-scale studies suggest that stimulating this nerve seems to reduce inflammation, although it’s not clear why.
Results from one trial showed that 75 per cent of patients had what is called ‘significant’ and ‘meaningful’ improvement when they had a small stimulator implanted next to the vagus nerve in their neck.
Scientists at the University of Amsterdam are planning a longer trial, involving more patients.