title: A long peripheral nerve autograft model in the sheep forelimb.
abstract: BACKGROUND
  Autologous nerve grafts remain the only proven means of bridging lengthy gaps in peripheral nerve. However, there is very little literature on a reliable long (> 5 cm) nerve autograft animal model.
  
  
  OBJECTIVE
  To establish a reproducible long nerve gap and autograft animal model that is clinically relevant but not cost prohibitive.
  
  
  METHODS
  The extent of nerve regeneration and electrophysiological recovery after segmental repair of a long nerve defect was evaluated with a sheep model. Thirteen Suffolk sheep were used. An 18-cm segment of radial sensory nerve was harvested from the forelimb, trimmed, divided into 2 equal segments of 7 cm each, and microsurgically repaired to a surgically created defect of 5 cm in the median nerve within the same forelimb. Electrophysiological studies were performed on 6 sheep at 6 months and 6 sheep at 9 months. Samples of the grafted segments were obtained for histology, immunohistochemistry, and morphometric analyses. Electric studies were also performed on an uninjured median nerve of a control animal in tissue that was similarly harvested and processed.
  
  
  RESULTS
  At 6 and 9 months, all sheep had recordable robust nerve action potentials. Nerve conduction velocity and amplitude were slightly decreased compared with control, but the difference was statistically insignificant. Histomorphometric assessment demonstrated that the autografts contained a large number of regenerating axons through graft fascicles in all animals.
  
  
  CONCLUSIONS
  The median nerve in the sheep forelimb is a reproducible and reliable model for assessing regeneration through long peripheral nerve grafts.
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Joanne
authors.initials: J
authors.lastname: Forden
authors.forename: Qing-Gui
authors.initials: QG
authors.lastname: Xu
authors.forename: Kathleen Joy
authors.initials: KJ
authors.lastname: Khu
authors.forename: Rajiv
authors.initials: R
authors.lastname: Midha
mesh_terms: D000818:Animals; D005260:Female; D008475:Median Nerve / Q000502:physiology* / Q000601:surgery*; D023421:Models, Animal; D009416:Nerve Regeneration / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology / Q000637:transplantation; D011826:Radial Nerve / Q000502:physiology* / Q000637:transplantation*; D034561:Sheep, Domestic; D016378:Tissue Transplantation / Q000379:methods; D014182:Transplantation, Autologous