Loss of movement due to injury is a devastating reality for many people. This is especially true for individuals who have sustained damage to their spinal cord. The World Health Organization (WHO) estimates that each year between 250,000 and 500,000 people experience a spinal cord injury, most often as a result of motor vehicle collisions, falls, or other accidents. Furthermore, WHO states that these individuals are two to five times more likely to die than people without a spinal cord injury. Spinal cord injury (SCI) frequently results in a lifelong sensorimotor deficit. Spontaneous recovery from SCI is limited, because supraspinal fibers cannot regenerate on their own to form functional networks below the level of injury. Unfortunately, until recently there was no treatment capable of reversing the loss of mobility experienced by these patients. Epidural stimulation is a therapy with the potential to help individuals with spinal cord injury, including those with paraplegia and tetraplegia, regain lost movement and control.
It involves implanting a small device on the protective covering of the spinal cord. This device generates electrical currents to stimulate the lower portion of the spinal cord, which otherwise is unable to communicate with the upper segments. These electrical currents are regulated by a remote control that allows the stimulation parameters to be adjusted. In combination with physiotherapy, patients can be trained to regain movement in their legs. This is currently the best available technology for spinal cord injuries. In addition to movement, it has the potential to help patients regain other functions such as bladder control, regulation of body temperature, sexual function, and muscle control.
The results of surgery and device implantation have been positive so far. Patients who have undergone this experimental procedure have regained movement in their legs and experienced further improvements. For example, as reported in a recent issue of the journal Nature Medicine, one recipient of the operation was able to bend his knees only two days after implantation of the epidural stimulator, while another patient was able to take steps on a treadmill. The response to stimulation that we obtained in completely immobile legs (C6 complete spinal injury) one day after surgery clearly demonstrates this effect.