Indications and Results of Implantable Functional Electrical Stimulation (FES) of the Peroneal Nerve

Drop foot is a common problem following neurological conditions such as stroke, multiple sclerosis (MS), traumatic brain injury (TBI), incomplete spinal cord injury (iSCI) and cerebral palsy (CP). Between 20 and 30% of patients entering neurological rehabilitation suffer from drop foot. Typically, drop foot is caused by weakness of the ankle dorsiflexors leading to a lack of foot elevation during the swing phase of gait, which is often accompanied by a tendency towards varus deviation at the ankle due to muscular imbalance. In addition, spasticity of the ankle plantarflexors may worsen equinovarus deviation as a result of muscle stiffness, contracture and pathological co-contraction. Drop foot leads to an abnormal gait pattern, decreased walking speed, limited endurance walking and increased fall risk. All these factors can limit mobility, independence and social participation leading to reduced quality of life.