Roadmap to a Facial Pacing Implant for paralysed and synkinetic re-innervated facial Muscles

Acute and chronic facial nerve palsies often cause severe functional impairment and loss of quality of life. Since previous surgical and conservative treatments often do not solve these impairments sufficiently or require a lot of time, electric pacemakers have been discussed as a therapy option for a long time. In the meantime, solutions have been found for many of the necessary technical and medical challenges. In this article we want to outline these development steps. To trigger the stimulation of the implants correctly, the derivation of the EMG activity of the healthy counterpart is an obvious solution, but also poses an operative risk for the healthy side. Optical detection of eye closure, detection of EMG activity of the ear muscles also innervated by the facial nerve, or decoding of synkinetic EMG activity of the affected muscles represent several already successfully tested solutions. The laryngeal pacemaker studies in animals and humans, among others, showed that electrodes, cables and implants can be implanted in a minimally invasive manner and are durable. In trial stimulations using surface and needle electrodes, the paralyzed muscles could be stimulated without pain. These trials showed stimulation parameters for both reinnervated and completely denervated muscles that could be generated by previously developed implants. Finally, clinical studies showed no evidence of negative effects of early electrostimulation on reinnervation, so that future implants could be indicated not only in chronic facial nerve palsy, but also used as temporal help in acute cases, when reinnervation can still be hoped for. Since the procedure is minimal invasive, reversible, and not hindering or counter productive for any of the standard therapies.

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Artikel online veröffentlicht:
12. Mai 2023