Fasciated nerve-muscle explants for in vitro comparison of magnetic and electrical neuromuscular stimulation

Neuromuscular stimulation has become a central technique for research and clinical efforts in rehabilitation, but available devices still do not show the needed performance in strength and selectivity for this approach. However, the knowledge about the exact intramuscular structure formed by the axons, muscle fibers with their different metabolism types and properties as well as the motoric endplates in between is still too rough for purely theoretical optimization. In this text, we present an experimental setup for parametrized studies of the spatial and temporal degrees of freedom (DOF) in electrical as well as magnetic stimulation. For clarification of the physiologic background, nerve-muscle explants are dissected and kept on life support in a nutrient system with glucose and oxygen supply. The setup provides two-channel EMG signals and a dynamic force signal. The design was adapted to meet the conditions for physical compatibility with magnetic stimulation and allows coil position sweeps with four (three translational and one rotational) DOF. The setup provides access to essential boundary conditions and means to simulate lesions as well as the influence of drugs. Besides with the presented setup, comparisons and even combined application of magnetic and electrical stimulation become possible on the level of the neuromuscular system. Finally, this approach shall help to improve rehabilitation by peripheral stimulation after nerve lesions. The focus of this text lies on the setup and the nutrition which will entail particular studies in the sequel.