Permanent LMN denervation of human skeletal muscle and recovery by h-b FES: management and monitoring

Abstract

Denervation of a defined skeletal muscle is due to lower motor neuron (LMN) or peripheral nerve lesions that have major consequences on the muscle tissue. After early atrophy, the midand late-phases presents two very contrasting myofibers populations: beside those severely atrophic with internalized groups of myonuclei, large fast-type muscle fibers continue to be present 4 to 6 years after Spinal Cord Injury (SCI). Recent results of rat experiments provides the rational basis for understanding the residual functional characteristics of the long-term denervated muscle and the molecular explanation of its ability to respond to home-base functional electrical stimulation (h-b FES) using custom-designed electrodes and stimulators. Further outcomes of the Vienna-Padova ten-year collaboration are: 1. a world-unique MyoBank of muscle biopsies and 2. improved imaging procedures (Color Computer Tomography (CT) scan and Functional Echomyography), all demonstrating that h-b FES induces improvements in muscle contractility, tissue composition and mass, despite permanent LMN denervation. The benefits of h-b FES could be extended from patents suffering with complete Conus-Cauda Syndrome to the numerous patients with incomplete LMN denervation of skeletal muscles to determine whether h-b FES reduces secondary complications related to disuse and impaired blood perfusion (reduction in bone density, risk of bone fracture, decubitus ulcers, and pulmonary thromboembolism). We are confident that translation of the results of a clinical experiment, the EU Project RISE, to the larger cohort of incomplete LMN denervated muscles will provide the wanted results. Key Words: LMN denervation, human skeletal muscle, managements, monitorings, h-b FES, Color CT scan, ultra sonography, Functional Echomyography Lower motor neuron (LMN) muscle denervation is a major clinical and experimental problem that attracted attention of biologists, physiologists and of the medical community even before the modern scientific era. The major issues for decades have been the nature of the neurotrophic influence and the denervationreinnervation constrains. A principal query was whether there is a trophic function of the neuron that is distinct from its role in impulse conduction and transmission, the neurothrophic hypothesis, a concept suggested by the centuries-old question of Prochaska (1784), cited in Gutmann, 1962 [44]. Much of this has been excellently reviewed by Midrio [77] and Carlson [23]. In the medical literature other major issues are the neurodegenerative disorders, where partial muscle h-b FES of denervated muscle: management and monitoring European Journal Translational Myology -Myology Reviews 1 (3): [91][92][93][94][95][96][97][98][99][100][101][102][103][104] 2010 -92 -denervation and reinnervation occurs concomitantly to the muscle disease process [22,110]. The ethiopathogenic analyses of these processes are difficult since pathomechanisms of denervation ought to be distinguished from those of a progressively insufficient reinner...

Effect of electrical stimulation on motor nerve regeneration in sciatic nerve ligated-mice

“…On the other hand, our results support recent clinical application of Functional Electrical Stimulation (FES) in Spinal Cord Injury (SCI) and aging patients. 53-60 …”

Relationship between peak and mean amplitudes of the stimulating output voltage for functional control of the knee by spinal cord patients and healthy volunteers

“…This result is most likely related to muscle atrophy in SCIVs (Andersen et al, 1999; Kern et al, 2010a) and the consequent difference in Ca ++ activation of cross bridges in sarcomere cells (Gobbo et al, 2006). FES may have triggered a muscle cell recovery process (Thrasher et al, 2006) and may also lead to hypertrophy (Kern et al, 2010b); thus, the stimulation amplitude required to achieve a knee flexion angle of 40° may decrease during the recovery process of neuromuscular tissue. Regarding peak amplitude, Figure 2 shows that P4 required the weakest amplitudes to achieve 40° of knee flexion for both HVs and SCIVs.…”