Subjective outcome following neurostimulator implantation as drop foot therapy due to lesions in the central nervous system-midterm results.

BACKGROUND: Drop foot can be caused by many conditions. Stroke is one of the major causes of drop foot and 5% of stroke survivors suffer from hemiplegia, which in some cases, can manifest as drop foot. The abnormal gait resulting from the lack of innervation of the extensor muscles may result in a secondary malposition of the foot and lead to a steppage gait. Among the several therapy options for the treatment of drop foot, functional electrostimulation (FES) with a transcutaneous peroneal nerve stimulator (tPNS) or an implantable peroneal nerve stimulator (iPNS) represents the two recent approaches.

OBJECTIVE: Although therapy with an iPNS has been proven to be effective, a subjective patient assessment has not yet been executed. The aim of this study was to assess the patient's satisfaction with the therapy by using two established surveys.

METHODS: The Rivermead Mobility Index (RMI) and the Reintegration to Normal Life Index (RNLI) were used for this retrospective study. The RMI includes 15 questions which are to be answered as either "yes" or "no" and given a value of 1 or 0, respectively, with a maximum of 15 points possible. The RNLI includes 11 questions which are to be answered with the use of a visual analog scale (VAS, 0 to 10 cm). In this case, a maximum adjusted score of 100 points is possible.

RESULTS: The total study cohort involved 56 patients treated with an iPNS. Thirty-five complete data sets for the RMI and 29 for the RNLI could be achieved. A significant difference in the total score of both surveys was observed between the deactivated and the activated iPNS (RMI: p = 0.02; RNL: p = 0.01).

CONCLUSION: A significant improvement in patient satisfaction was detected with the use of an activated iPNS after a mean time span of 4 years. Due to the marked mobility, an increase in the social satisfaction and integration could be achieved. Both aspects represent essential components for the recovery and quality of life of the patients.