The purpose of this project is to investigate the safety and effective of an Implanted Dropped Foot Stimulator. This medical device is a 2 channel implanted neuromuscular stimulator intended for the correction of dropped foot following stroke.
The nerve that controls the lifting of the foot in walking is called the common peroneal nerve. At a point, just below the knee, this nerve splits into two branches, the deep branch and the superficial branch. The deep branch goes to the muscles that lift (dorsiflex) and turn inward (inversion) the foot while the superficial branch supplies the muscles that turn the foot outwards (eversion). In normal walking, a combination of these movements is required. Therefore an electrode is surgically inserted in both nerves enabling the movements to be controlled separately. This causes nerve impulses to travel down the nerve to the muscle in the same way as naturally occurring nerve impulses. Stimulation begins when the foot is lifted and ends when the heel is returned to the ground. Sensation from the electrical stimulation should be very slight and it is expected that users will quickly become accustomed to it. Once healing has occurred the operation site scars should be negligible. It may be possible to palpate the implant under the skin but it is not expected to be noticeable to the eye.