title: The degree of facial movement following microvascular muscle transfer in pediatric facial reanimation depends on donor motor nerve axonal density.
abstract: BACKGROUND
  Free functional muscle transfer to the face is a standard of facial animation. The contralateral facial nerve, via a cross-face nerve graft, provides spontaneous innervation for the transferred muscle, but is not universally available and has additional shortcomings. The motor nerve to the masseter provides an alternative innervation source. In this study, the authors compared donor nerve histomorphometry and clinical outcomes in a single patient population undergoing free muscle transfer to the face.
  
  
  METHODS
  Pediatric patients undergoing dynamic facial (re-)animation with intraoperative nerve biopsies and gracilis transfer to the face powered by either the contralateral facial nerve via a cross-face nerve graft or the motor nerve to the masseter were reviewed over a 7-year period. Myelinated nerve counts were assessed histomorphometrically, and functional outcomes were evaluated with the Scaled Measurement of Improvement in Lip Excursion software.
  
  
  RESULTS
  From 2004 to 2011, 91 facial (re-)animation procedures satisfied study inclusion criteria. Average myelinated fiber counts were 6757 per mm2 in the donor facial nerve branch, 1647 per mm in the downstream cross-face nerve graft at the second stage, and 5289 per mm in the masseteric nerve. Reconstructions with either innervation source resulted in improvements in oral commissure excursion and smile symmetry, with the greatest amounts of oral commissure excursion noted in the masseteric nerve group.
  
  
  CONCLUSIONS
  Facial (re-)animation procedures with use of the cross-face nerve graft or masseteric nerve are effective and result in symmetric smiles. The masseteric nerve provides a more robust innervation source and results in greater commissure excursion.
  
  
  METHODS
  Therapeutic, III.
authors: St. Louis, Mo.; Liverpool, United Kingdom; and Toronto, Ontario, Canada From the Facial Nerve Institute, Department of Surgery, Division of Plastic and Reconstructive Surgery, Washington University School of Medicine; the Facial Nerve Program, Regional Pediatric Burns and Plastic Surgery Service, Alder Hey Children's NHS Foundation Trust; the Department of Surgery, Division of Plastic Surgery, and the Department of Pediatric Laboratory Medicine, Division of Pathology, The Hospital for Sick Children; and the Division of Plastic and Reconstructive Surgery, University of Toronto.
authors: Alison K
authors: AK
authors: Snyder-Warwick
authors: Adel Y
authors: AY
authors: Fattah
authors: Leanne
authors: L
authors: Zive
authors: William
authors: W
authors: Halliday
authors: Gregory H
authors: GH
authors: Borschel
authors: Ronald M
authors: RM
authors: Zuker
mesh_terms: D001369:Axons / Q000648:ultrastructure; D002452:Cell Count; D002648:Child; D004954:Esthetics; D005146:Facial Asymmetry / Q000517:prevention & control; D005149:Facial Expression; D005152:Facial Muscles / Q000294:innervation / Q000502:physiology*; D005154:Facial Nerve / Q000502:physiology / Q000601:surgery*; D005158:Facial Paralysis / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008340:Mandibular Nerve / Q000502:physiology / Q000601:surgery*; D008406:Masseter Muscle / Q000294:innervation; D009046:Motor Neurons / Q000502:physiology*; D009068:Movement; D018482:Muscle, Skeletal / Q000637:transplantation*; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D016067:Nerve Transfer / Q000379:methods; D019651:Plastic Surgery Procedures / Q000379:methods*; D020127:Recovery of Function; D012904:Smiling / Q000502:physiology; D014019:Tissue Donors; D016042:Transplantation, Heterotopic; D019737:Transplants / Q000294:innervation / Q000502:physiology*; D016896:Treatment Outcome
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