Breakthrough nerve-attached bionic leg tackles pain for amputees
Leg and foot amputees suffer from various kinds of pain, including phantom pain in the lost limb, neuroma or stump pain localised to the remaining body part after amputation. Various pharmacological approaches as well as complementary or alternative neuromodulatory therapies exist for addressing chronic pain in these individuals but with limited success. An innovative limb prosthesis The EU-funded IPS project proposed an alternative approach for giving amputees back their leg feeling. They developed an innovative sensory feedback technology and incorporated it in the leg prosthesis, which feeds back information to the brain. “The aim was to develop a prosthesis that feels similar to a natural foot when walking,″ explains Rainer Schultheis, CEO and co-founder of Saphenus Medical Technology GmbH, the company that developed the prosthesis. The proprietary prosthesis – commercialised under the trademark name Suralis – consists of a sensor sock, which detects rolling movement through a set of vibrotactile actuators. The information from the ground is then transmitted to the nerves of the leg and finally to the brain. As a result, the brain doesn’t have to search for the lost limb, the prosthesis is more easily accepted by the body, and the phantom pain goes away. Traditional bionic limbs use electromyographical electrodes to sense electric signals in the remaining muscles and convert these into bionic limb movement. The Suralis prosthesis relies on the bionic principle but instead of muscles takes advantage of sensory nerves that were in use before amputation. Sensory information is thus processed and relayed to the brain in the same way as it would for a healthy leg. Unlike conventional bionic limbs, Suralis employs targeted sensory reinnervation, a surgical approach, to attach the prosthesis to the amputated limb. Schultheis is confident that further optimisation of the procedure as well as its simultaneous execution with amputation will realise an authentic feeling of a leg for patients. The Suralis prosthesis merits Phantom pain is usually treated with strong medication like morphine and opiates. These pain killers have massive side effects and affect the quality of life of amputees. When tested in clinical studies, the Suralis prosthesis gave back the feeling of the lost limb, increased gait stability and individuals walked longer distances. Importantly, according to testimonials, it reduced or even eliminated the phantom pain. These observations have persisted for at least five years. The IPS project has succeeded in uniquely combining sophisticated, miniaturised technology and medicine. The Suralis prosthesis solution is cost-efficient and affordable, estimated to reach the market at an up to 85 % lower price than existing solutions. It is expected to provide healthcare-associated savings of more than EUR 24 000 per year per individual coupled with obvious social benefits. Social and healthcare institutions have recognised the merits of Suralis as it provides advanced care to amputees, opening avenues for its use in healthcare systems across Europe. In view of the future, Schultheis outlines: “Our long term goal is to bring back the feeling to the wearer of prosthesis. This bionic prosthesis should be a standard in prosthetic care similar to the way eye glasses are used to correct eyesight impairment.″
Keywords
IPS, Suralis prosthesis, sensory, amputee, phantom pain, targeted sensory reinnervation
