Assessment of a two-channel implantable peroneal nerve stimulator post-stroke

Abstract

A stroke is one of the most important causes of permanent invalidity. In the Netherlands, each year 41,000 people are involved with a first stroke. A motor impairment which is commonly seen in stroke survivors is a drop foot. The abnormal, inefficient and unsafe walking pattern hinders patients to perform their activities of daily living, resulting in an impaired quality of life. In the past several solutions have been developed for the treatment of a drop foot. Functional electrical stimulation (FES) of the peroneal nerve is one of the treatment options that can be used. Although this concept has existed for more than 40 years, the use of FES is not widespread and the total number of patients being treated remains quite small. Several reasons can be responsible for this finding, such as technical limitations and unfamiliarity with FES in many countries. In addition there is still no hard evidence for the positive clinical effects of this treatment. An interesting aspect that has not been clarified yet is the additional value of peroneal nerve stimulation in comparison with the treatment that is normally given to stroke survivors, i.e. a passive walking device. The aim of the present thesis was to attribute to a more evidence based stroke rehabilitation regarding the correction of a drop foot by FES. A RCT was performed to evaluate the effect of an implantable two-channel peroneal nerve stimulator on impairment, disability and quality of life in comparison with the effect of the conventional treatment given to stroke survivors with a drop foot, in most cases an ankle-foot orthosis (AFO). Summarizing, the results of this thesis indicate that the STIMuSTEP is a clinical effective device in a selected group of chronic stroke subjects with a drop foot. When comparing this neuroprosthetic device with the standard of care, an AFO or orthopaedic shoes, a clinically relevant orthotic effect on mobility, ankle kinematics and quality of life was found. However, no convincing therapeutic effect of PNS was found in the present RCT.