title: Smile reconstruction in adults with free muscle transfer innervated by the masseter motor nerve: effectiveness and cerebral adaptation.
abstract: BACKGROUND
  This study assesses the ability of the masseter motor nerve-innervated microneurovascular muscle transfer to produce an effective smile in adult patients with bilateral and unilateral facial paralysis.
  
  
  METHODS
  The operation consists of a one-stage microneurovascular transfer of a portion of the gracilis muscle that is innervated with the masseter motor nerve. The muscle is inserted into the cheek and attached to the mouth to produce a smile. The outcomes assessed were the amount of movement of the transferred muscle; the aesthetic quality of the smile; the control, use, and spontaneity of the smile; and the functional effects on eating, drinking, and speech. The study included 27 patients aged 16 to 61 years who received 45 muscle transfers.
  
  
  RESULTS
  All 45 muscle transfers developed movement. The commissure movement averaged 13.0 +/- 4.7 mm at an angle of 47 +/- 15 degrees above the horizontal, and the mid upper lip movement averaged 8.3 +/- 3.0 mm at 42 +/- 17 degrees. Age did not affect the amount of movement. Patients older than 50 years had the same amount of movement as patients younger than 26 years (p = 0.605). Ninety-six percent of patients were satisfied with their smile.
  
  
  CONCLUSIONS
  A spontaneous smile, the ability to smile without thinking about it, occurred routinely in 59 percent and occasionally in 29 percent of patients. Eighty-five percent of patients learned to smile without biting. Age did not affect the degree of spontaneity of smiling or the patient's ability to smile without biting.
authors.affiliation: Toronto, Ontario, Canada From the Division of Plastic Surgery, Toronto General Hospital, University Health Network; Division of Plastic Surgery, Hospital for Sick Children; and Toronto Western Hospital, University Health Network.
authors.forename: Ralph T
authors.initials: RT
authors.lastname: Manktelow
authors.forename: Laura R
authors.initials: LR
authors.lastname: Tomat
authors.forename: Ron M
authors.initials: RM
authors.lastname: Zuker
authors.forename: Mary
authors.initials: M
authors.lastname: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology; D005158:Facial Paralysis / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000294:innervation; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation* / Q000637:transplantation*; D019651:Plastic Surgery Procedures / Q000379:methods*; D012904:Smiling / Q000502:physiology; D013524:Surgical Flaps; D016896:Treatment Outcome