Neuromuscular stimulation of the leg

Abstract

Disorders of the circulation of the leg are a problem in both the developed and developing world, and are a major cause of morbidity and mortality. The incidence of diabetes is increasing, the population is ageing, and resources to treat vascular disease are finite. Exercise can augment the circulation, and has many beneficial effects on the cardiovascular system as a whole. Electrical stimulation of the muscles of the leg may work in a similar fashion to both voluntary contraction and external muscle compression, in that venous return is increased, and symptoms of vascular disease are reduced. This body of work aims to delineate the clinical problems to which this solution should be applied, carry out preliminary testing and pilot trials to assess feasibility and effect size of electrical therapy, and to design a device which best addresses the needs of the identified population. Hypothesis Neuromuscular electrical stimulation (NMES) of the leg increases the circulatory parameters of the leg, and treatment with NMES over time will alleviate clinical symptoms of vascular disease and improve quality of life. Methods The incidence of medical morbidity related to vascular disease was explored, and target populations requiring development of current inadequate management strategies were identified. Neuromuscular electrical stimulation has been defined, and the history of the use of electrical therapies has been reviewed. Bench testing and small trials were conducted to evaluate the physiological impact of neuromuscular electrical stimulation device usage, and how they compare to current standards of non-pharmaceutical and non-operative medical care (e.g. graduated compression, intermittent pneumatic compression). Clinical trials in patient groups of interest were instituted, looking specifically at chronic venous disease, peripheral arterial disease, and diabetic vascular complications. Results Flow rates and speed of blood in the femoral vessels increased in both healthy subjects and those with vascular disease. Those patients with severe diabetic foot complications were more resistant to flow changes. Fluximetry measurements taken from the foot increased with NMES device use. Improvements in functional outcomes were shown, particularly in the management of claudication and wound healing in the diabetic foot. Quality of life measures improved but on the whole were not statistically significant. Conclusions The judicious use of NMES in patients with vascular disease could prove useful, especially in the setting of multiple comorbidities and polypharmacy. The risk profile is very low, especially when compared to anticoagulants or surgery. The health economic benefits are not known, but future studies could use the data in this thesis to power future trials. The biological effects of device usage, both long and short term have not been explored, and may be amenable to testing in further trials in humans.