title: Stimulation of denervated muscle promotes selective reinnervation, prevents synkinesis, and restores function.
abstract: OBJECTIVE
  Previously, electrical stimulation of denervated canine laryngeal muscle was shown to promote reinnervation by native over foreign motoneurons. The goal of this study was to assess the effect of different stimulus paradigms on reinnervation quality and functional recovery.
  
  
  METHODS
  A prospective study of six canines over 8 to 20 months.
  
  
  METHODS
  A clinical model of laryngeal paralysis was used, where recurrent laryngeal nerves of the animals were sectioned and ventilation compromised. The abductor, posterior cricoarytenoid (PCA) muscles were implanted bilaterally with electrodes from an implantable pulse generator. Animals were randomly assigned to three groups to assess the effect of different stimulus paradigms: 1) 40 pulses per second (pps) train, 2) 10 pps train, 3) no stimulation. Spontaneous vocal fold movement was measured endoscopically during hypercapnia. Exercise tolerance was measured on a treadmill using pulse oximetry. In the terminal session, electromyography (EMG) potentials were recorded during superior laryngeal nerve stimulation to index foreign reinnervation of the PCA by reflex glottic closure (RGC) motoneurons.
  
  
  RESULTS
  After reinnervation started, nonstimulated and stimulated 40 pps animals displayed paradoxical closure of the glottis during hypercapnia and severely decreased exercise tolerance due to faulty reinnervation. In contrast, stimulated 10 pps animals displayed minimal paradoxical closure and normal exercise tolerance (12 minutes up to 8 mph). EMG findings in this group demonstrated significantly less PCA reinnervation by foreign RGC motoneurons.
  
  
  CONCLUSIONS
  PCA stimulation with low frequency reduced synkinetic reinnervation by foreign RGC motoneurons. Paradoxical closure of the glottis with inspiration was reduced and exercise tolerance restored to normal.
authors.affiliation: Department of Otolaryngology, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: David L
authors.initials: DL
authors.lastname: Zealear
authors.forename: Rajshri
authors.initials: R
authors.lastname: Mainthia
authors.forename: Yike
authors.initials: Y
authors.lastname: Li
authors.forename: Isamu
authors.initials: I
authors.lastname: Kunibe
authors.forename: Akihiro
authors.initials: A
authors.lastname: Katada
authors.forename: Cheryl
authors.initials: C
authors.lastname: Billante
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Nomura
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000008:administration & dosage; D004195:Disease Models, Animal; D004285:Dogs; D004558:Electric Stimulation; D004576:Electromyography; D005080:Exercise Test; D007821:Laryngeal Muscles / Q000294:innervation* / Q000502:physiology; D007828:Laryngoscopy; D009121:Muscle Denervation; D009416:Nerve Regeneration / Q000502:physiology*; D011446:Prospective Studies; D011897:Random Allocation; D020127:Recovery of Function; D012009:Recurrent Laryngeal Nerve / Q000503:physiopathology* / Q000601:surgery; D046608:Synkinesis / Q000503:physiopathology*; D014826:Vocal Cord Paralysis / Q000503:physiopathology* / Q000601:surgery
chemical_list: D002245:Carbon Dioxide
keywords: EMG; denervation; motor units; regeneration; synkinesis; ventilation