Pre-clinical evaluation of a minimally invasive laryngeal pacemaker system in mini-pig

Abstract

Microlaryngoscopic enlargement techniques have been the standard treatment for bilateral vocal fold paralysis (BVFP) for decades. Laryngeal pacing is a promising alternative treatment based on the electrostimulation of the posterior cricoarytenoid (PCA) muscle. This paper reports on the results of a pre-clinical study aiming to evaluate this method. Eight Göttingen mini-pigs were implanted with a laryngeal pacemaker (LP) implant prototype and with two LP electrodes, one in each PCA muscle. The 6-week follow-up included endoscopic stimulation controls in general anaesthesia and radiographic controls of electrode integrity and position stability. Stimulation parameters for optimal glottal opening were evaluated via videolaryngoscopy. Histopathology was performed upon conclusion of the study. 7/8 (87.5 %) animals were successfully implanted with the LP implant prototype and two LP electrodes. In general, stimulation was effectively delivered and correlated with the expected PCA muscle activation. 2/14 (14.3 %) electrodes dislocated and 1/14 (7.1 %) electrode tip broke. The LP system used in this experiment to induce vocal fold abduction by means of selective functional electrical stimulation of the PCA showed promising results. It may be a valid alternative to the current golden standard for BVFP treatment. Clinical studies are needed to confirm the medical relevance of the LP.

Towards the clinical translation of optogenetic skeletal muscle stimulation

“…Furthermore, electrical stimulation of the posterior cricoarytenoid muscle has been explored since the 1970s in various animal species, as well as in patients. While opening of the vocal folds is in principle possible [31,41,104,114,[160][161][162], severe sideeffects prevent its routine clinical application. These sideeffects include corrosion or encapsulation of the electrode tip reducing the efficiency of stimulation, discomfort due to the activation of sensory nerves, and co-stimulation of antagonistic muscles, which in some patients requires the selective silencing of antagonistically acting muscle groups by repetitive botulinum toxin injections [160,161].…”

Unilateral and Bilateral Laryngeal Pacing for Bilateral Vocal Fold Paralysis

“…Then the insertion tool was removed, and the electrode was fixated to the ventral aspect of the cricoid arch [27]. In order to deliver stimulation, Förster et al [28] then connected the electrode to an external digital interface box (MED-EL) and tested the integrity and stimulation capacity of the implant in normally innervated mini pigs.…”

Smart Artificial Soft Tissue - Application to a Hybrid Simulator for Training of Laryngeal Pacemaker Implantation

“…Apart from preclinical evaluation of the LP system [19], functional testing is also usually performed on animals to evaluate the evoked responses to electrical stimulation. Not only ethical concerns might arise from animal testing but also high costs might be associated.…”