title: Improving electrophysiologic and histologic outcomes by photochemically sealing amnion to the peripheral nerve repair site.
abstract: BACKGROUND
  The surgical approach used today in the repair of peripheral nerve injuries rarely achieves full functional recovery. This study determines whether isolation of the nerve repair site using photochemical tissue bonding (PTB) in combination with human amniotic membrane can improve both functional and histologic recovery.
  
  
  METHODS
  New Zealand white rabbits (n = 24) underwent transection of the right common peroneal nerve. Epineural nerve repair was performed using 10-0 nylon sutures. The repair site was then wrapped in a cuff of human amniotic membrane, which either was secured with sutures or sealed using PTB. Standard neurorrhaphy alone was assessed as a control group. Functional recovery was recorded at 30-day intervals postoperatively by electrophysiologic assessment. At 120 days, animals were killed humanely and nerves harvested for histomorphometry.
  
  
  RESULTS
  Nerves treated with amnion wraps and sealed with PTB demonstrated a statistically significant improvement across both functional and histologic parameters. Functional recovery, as measured by repeated electrophysiologic studies over time, revealed a 26.2% improvement over standard neurorrhaphy alone (P < .05). Nerves treated with PTB-sealed amnion wraps had significantly greater (P < .001) axon (5.08 +/- 1.06 microm) and fiber diameters (7.46 +/- 1.37 microm), as well as myelin thickness (2.39 +/- 0.7 microm) and the g ratio (axon diameter/fiber diameter ratio; 0.68 +/- 0.07) distal to the repair site compared to standard neurorrhaphy alone (4.98 +/- 1.81 microm, 6.77 +/- 1.94 microm, 1.79 +/- 0.42 microm, and 0.71 +/- 0.09, respectively).
  
  
  CONCLUSIONS
  Isolation of the repair site using a photochemically sealed amnion wrap improves electrophysiologic and histologic recovery compared to standard suture neurorrhaphy.
authors.affiliation: Plastic Surgery Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Francis P
authors.initials: FP
authors.lastname: Henry
authors.forename: Namita A
authors.initials: NA
authors.lastname: Goyal
authors.forename: William S
authors.initials: WS
authors.lastname: David
authors.forename: David
authors.initials: D
authors.lastname: Wes
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Bujold
authors.forename: Mark A
authors.initials: MA
authors.lastname: Randolph
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Winograd
authors.forename: Irene E
authors.initials: IE
authors.lastname: Kochevar
authors.forename: Robert W
authors.initials: RW
authors.lastname: Redmond
mesh_terms: D000650:Amnion; D000818:Animals; D001684:Biological Dressings; D005260:Female; D006801:Humans; D023421:Models, Animal; D009416:Nerve Regeneration / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000166:cytology* / Q000502:physiology*; D010543:Peroneal Nerve / Q000166:cytology / Q000502:physiology; D010777:Photochemistry / Q000379:methods*; D011817:Rabbits; D020127:Recovery of Function / Q000502:physiology