Multiple Nerve Transfers to a Common Target Muscle facilitate High Fidelity Prosthetic Control
Matthias Luft, MD1, Johanna Klepetko, Medical student2, Silvia Muceli, PhD3, Jaime Ibáñez, Dr.4, Tereshenko Vlad, MD2, Christopher Festin, MD2, Olga Politikou, MD1, Gregor Laengle, MD1, Dario Farina, PhD5, Konstantin D Bergmeister, MD PhD1 and Oskar C Aszmann, MD, PhD6, (1)Medical University of Vienna, Vienna, Austria, (2)Medical University Vienna, Vienna, Austria, (3)Chalmers University of Technology, Gothenburg, Sweden, (4)Imperial College London, London, United Kingdom, (5)Department of Neurorehabilitation Engineering, Georg-August University, Göttingen, Germany, (6)CD Laboratory for Restoration of Extremity Function, Division of Plastic and Reocnstructive Surgery, Medical University of Vienna, Vienna, Austria
BACKGROUND: Muscles are effective amplifiers of neural information. In recent years we have demonstrated the feasibility of man-machine interfacing via "Bio-Screens". This is achieved by redirecting nerves which have lost their target after amputation to new targets (targeted muscle reinnervation). Yet, the number of control signals generated by targeted muscle reinnervation only provides basic extremity function of myoelectric prosthetics. Here we present a novel procedure by transferring multiple nerves onto a single target muscle to increase the resolution of neural signaling and thus prosthetic control in a rat model.
METHODS: The distal branch of the ulnar nerve alone (n=29) or together with the anterior interosseus nerve (n=30) were transferred to reinnervate the long head of the biceps in Sprague-Dawley rats. After twelve weeks of regeneration, we analyzed muscle function using newly developed multi-channel EMG-electrodes. Structural analyses included retrograde tracing, muscle fiber typing and immunohistochemical muscle staining.
RESULTS: All nerves successfully innervated the long head of the biceps as indicated by EMG and retrograde tracing. In addition, the number of motor units significantly increased following single or double nerve transfer (hyper-reinnervation). We thus recorded motor unit action potentials from double reinnervated muscles with excellent signal-to-noise ratio. However, the donor nerves are expected to change the target muscle fiber type population. As analyses are ongoing, detailed results will be presented at the conference.
CONCLUSION: This rat model demonstrates that a muscle can reliably host multiple nerves and that topographically distinct compartments will emerge within the target muscle that can be activated independently. This approach thus leads to a polytopic neural matrix that can display sets of motoneurons of the entire motoneuronal population of the amputated limb. High density EMG pick-up electrodes and adequate signal processing can decipher the neural code and be used for high-fidelity prosthetic control.
Back to 2022 Abstracts