Dr Rui Loureiro, Senior Lecturer in the Department of Materials and Tissue.
Illustration Lucinda Rogers
Phantom limb pain is caused by the brain’s natural signalling processes: the brain sends out a signal, gets nothing back, and the pain gets worse
The concept of ‘phantom limbs’ in amputees is well known. Treatment is often aimed at reminding the body that a limb has been removed, and managing or blocking the physical pain. But here at UCL Aspire CREATe (Centre for Rehabilitation Engineering and Assistive Technology), we are taking a radical new approach – using virtual reality to trick the brain into believing there is no pain because the limb is still there.
Phantom limb pain is caused by the brain’s natural signalling processes; it’s very real and extremely acute. Because the brain sends out a signal but gets nothing back, the pain gets worse until it reaches chronic levels, making using a prosthetic replacement impossible. But our work with the London Spinal Cord Injury Centre and the Peripheral Nerve Injury Unit helps patients eradicate neuropathic pain so they are able to use state-of-the-art prosthetic limbs that meld with their own muscles and nerves.
When we begin with a patient, the pain has made their joints very stiff (which also exacerbates discomfort) so we first use robots to vibrate the arm. This brings the muscle tone down, makes the joint flaccid and enables us to engage the muscles. We then strap the relaxed joint into another machine to help it to move – controlled by the patient – and use virtual reality (VR) to give the patient a series of tasks.
With VR, the patient suddenly has ‘a hand’, which sends a message to the brain to use the muscles to control it. When they do this, the brain doesn’t just get visual feedback, but neural feedback too, and we start to rebuild lost neural pathways.
We can then 3D print a bespoke prosthetic hand, so they can take those neural pathways built in the VR world and use them in the real world, before constructing a permanent replacement hand that they can control, as the rest of us do, with neural pathways. Most crucially, correct signalling to and from the brain means it has no reason to perceive pain, which then diminishes.
Our trials, alongside the UCL Robotics Research Group, have been fantastically successful: we gave nine patients just 11 therapy sessions – and no drugs – and reduced their pain levels by an average of 68 per cent. The cost of a hand is around £4,000. The alternative is lifelong pain-management treatment that would cost around £500,000.
These methods do not just help amputees to adjust, but also those awaiting amputation. The impact is not pain management, but to prevent maladaption from happening in the first place.
In my work I feel the most excited when I realise the impact our research has on other human beings. For all the laboratory triumphs, the real reward is seeing how our work changes lives, and this is a stunning and exciting example of that with implications for the future.
I’m also excited to be working at UCL, an academic, engineering, innovation powerhouse. No-one has our cross-disciplinary teams, combined with the wonderful medical facilities. No-one has the combination of minds that we do.
My dream is to see this treatment in an innovations clinic on the NHS: £4,000 and four weeks of treatment against £500,000 to manage a lifetime of pain? Think how many more patients could be treated, how many lives could be changed, with the money saved. Now that’s a reason to be excited!
Dr Rui Loureiro is ASPIRE Senior Lecturer in the Division of Surgery and Interventional Science, Department of Materials and Tissue, and Head of the Aspire CREATe Centre.