After spinal cord injury (SCI), patients spend daily several hours in wheelchairs, sitting on their hamstring muscles. SCI causes muscle atrophy and wasting, which is especially severe after complete and permanent damage to lower motor neurons. A European Union (EU)-supported work demonstrates that electrical fields produced by large electrodes and purpose-developed electrical stimulators recover both quadriceps and hamstring muscles, producing a cushioning effect capable of benefitting SCI patients, even in the worst case of complete and long-term lower motor neuron denervation of leg muscles. We reported that 20 out of 25 patients completed a 2-year h-bFES program, which resulted in (1) a 35% increase in cross-sectional area of the quadriceps muscles (P < 0.001), (2) a 75% increase in mean diameter of quadriceps muscle fibers (P < 0.001), and (3) improvement of the ultrastructural organization of contractile machinery and of the Ca2+-handling system. Though not expected, after 2 years during which the 20 subjects performed 5 days per week h-bFES of the atrophic quadriceps muscles, the CT cross-sectional area of the hamstring muscles also augmented, increasing from 26.9+/-8.4 (cm2) to 30.7+/-9.8 (cm2), representing a significant (p ≤ 0.05) 15% increase. Here we show by quantitative muscle color computed tomography (QMC-CT) that h-bFES-induced tissue improvements are present also in the hamstring muscles: a once supposed drawback (lack of specificity of muscle activation by large surface electrodes) is responsible for a major positive clinical effect. Interestingly, 2 years of home-based FES by large surface electrodes reversed also the denervation-induced skin atrophy, increasing epidermis thickness. Finally, we would like to attract attention of the readers to quantitative muscle color computed tomography (QMC-CT), a sensitive quantitative imaging analysis of anatomically defined skeletal muscles introduced by our group to monitor atrophy/degeneration of skeletal muscle tissue. Worldwide acceptance of QMC-CT will provide physicians an improved tool to quantitate skeletal muscle atrophy/degeneration before and during rehabilitation strategies so that therapy for mobility-impaired persons can be better prescribed, evaluated, and altered where needed.
Keywords: Home-based functional electrical stimulation; Muscle atrophy; Quantitative muscle color computed tomography.