Spinal(脊椎的) implants allow the paralyzed(瘫痪) to walk, swim and cycle again.
Four years ago Michel Roccati was involved in a motorcycle accident. He lost all sensation below the site of the damage to his spine and he could no longer move his legs. In December last year, however, the young Italian stood up on the streets of Lausanne, Switzerland, and took a short walk.
Mr Roccati's remarkable steps, supported by a wheeled walking frame. were the conclusion of more than a decade of work by Gregoire Courtine, a neuroscientist(神经学家) at the Federal Institute of Technology in Lausanne, and Jocelyne Bloch, a neurosurgeon at Lausanne University Hospital.
The scientists had fitted Mr Roccati with a thin device that stimulated nerves in his back that once controlled muscles in his lower body and legs, which lay senseless after his accident. Even after a severe spinal injury, the nerves controlling activities often remain undamaged below any damaged tissue. In paralyzed people, however, the damaged tissue interrupts or weakens any electrical signals from the brain. Dr Courtine and Dr Bloch developed a thin device with electrodes(电击) that targeted the senseless nerves. Once implanted into Mr Roccati's back, the device acted like an amplifier(扩大器) for any electrical signals from his brain and sent in electrical impulses like those normally present in the nerves of an uninjured person. Thus, Mr Roccati was able to voluntarily control those once-senseless nerves and move his legs and walk.
Mr Roccati was one of the three paralyzed volunteers who took part in a small clinical trial of the device. Two other trials were able to stand up and take a few steps almost immediately after they had recovered from the surgery to have it implanted. The device can also be fitted to fire its electrical impulses in many different patterns corresponding to different activities. Patients in the trial were not only able to stand and walk, but to swim and cycle.
The device will need approval from medical regulators before it can be used and commercialized in clinics.
