title: Correlation between Facial Nerve Axonal Load and Age and Its Relevance to Facial Reanimation.
abstract: BACKGROUND
  Two-stage facial reanimation procedures with a cross-facial nerve graft often have unsatisfactory results in the older patient. Although the cause of result variability is likely multifactorial, some studies suggest that increased donor nerve axonal load improves function of a free muscle transfer after a cross-facial nerve graft. This study attempts to characterize the relationship between age and facial nerve axonal load.
  
  
  METHODS
  Sixty-three fresh cadaveric heads were dissected to expose the facial nerve. For each hemiface, two facial nerve samples were taken: one proximal as the nerve exits the stylomastoid foramen, and one distal at the buccal branch (at a point 1 cm proximal to the anterior parotid border). Nerve samples were stained and quantified. Correlation analysis was completed using a Pearson correlation coefficient.
  
  
  RESULTS
  Thirty-six female and 27 male cadavers were dissected; their average age was 71 years (range, 22 to 97 years). At the proximal (r = -0.26; p < 0.01; n = 104) and distal (r = -0.45; p < 0.0001; n = 114) sampling points, there was a significant negative correlation between age and axonal load.
  
  
  CONCLUSIONS
  As age increases, the axonal load of the facial nerve decreases at the buccal and zygomatic branches approximately 1 cm proximal to the anterior parotid border. The authors previously suggested this location as significant for cross-facial nerve coaptation. These results propose that decreasing axonal load can be a factor in the unsatisfactory outcomes of cross-facial grafting in the aging population. Moreover, this underscores the importance of recruiting more donor axons in attempting to improve facial reanimation in the older patient.
authors.affiliation: Dallas, Texas.|From the Department of Plastic Surgery; the Department of Pathology, Division of Neuropathology, and the Division of Biostatistics, University of Texas Southwestern Medical Center.
authors.forename: Austin
authors.initials: A
authors.lastname: Hembd
authors.affiliation: Dallas, Texas.|From the Department of Plastic Surgery; the Department of Pathology, Division of Neuropathology, and the Division of Biostatistics, University of Texas Southwestern Medical Center.
authors.forename: Purushottam
authors.initials: P
authors.lastname: Nagarkar
authors.affiliation: Dallas, Texas.|From the Department of Plastic Surgery; the Department of Pathology, Division of Neuropathology, and the Division of Biostatistics, University of Texas Southwestern Medical Center.
authors.forename: Justin
authors.initials: J
authors.lastname: Perez
authors.affiliation: Dallas, Texas.|From the Department of Plastic Surgery; the Department of Pathology, Division of Neuropathology, and the Division of Biostatistics, University of Texas Southwestern Medical Center.
authors.forename: Andrew
authors.initials: A
authors.lastname: Gassman
authors.affiliation: Dallas, Texas.|From the Department of Plastic Surgery; the Department of Pathology, Division of Neuropathology, and the Division of Biostatistics, University of Texas Southwestern Medical Center.
authors.forename: Philip
authors.initials: P
authors.lastname: Tolley
authors.affiliation: Dallas, Texas.|From the Department of Plastic Surgery; the Department of Pathology, Division of Neuropathology, and the Division of Biostatistics, University of Texas Southwestern Medical Center.
authors.forename: Joan
authors.initials: J
authors.lastname: Reisch
authors.affiliation: Dallas, Texas.|From the Department of Plastic Surgery; the Department of Pathology, Division of Neuropathology, and the Division of Biostatistics, University of Texas Southwestern Medical Center.
authors.forename: Charles L
authors.initials: CL
authors.lastname: White
authors.affiliation: Dallas, Texas.|From the Department of Plastic Surgery; the Department of Pathology, Division of Neuropathology, and the Division of Biostatistics, University of Texas Southwestern Medical Center.
authors.forename: Shai M
authors.initials: SM
authors.lastname: Rozen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001369:Axons; D002102:Cadaver; D004210:Dissection; D005151:Facial Injuries / Q000601:surgery; D005152:Facial Muscles / Q000294:innervation*; D005154:Facial Nerve / Q000033:anatomy & histology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013524:Surgical Flaps / Q000294:innervation* / Q000637:transplantation; D055815:Young Adult