title: Involuntary, electrically excitable nerve transfer for denervation: results from an animal model.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficacy of "paralyzed" nerve transfer (ie, transfer of an involuntary, nondegenerated, electrically excitable nerve onto an involuntary, degenerated, non-electrically excitable nerve) and functional electrical stimulation for reinnervation. We hypothesized that lower motor neuron cell body continuity with the motor cortex, via intact upper motor neurons, is not necessary for reinnervation of the extremities.
  
  
  METHODS
  Fischer 344 rats had lower thoracic spinal cord injury (SCI) followed by unilateral tibial nerve transection and delayed peroneal ("paralyzed") to tibial nerve transfer (group A) or primary neurorrhaphy (group B). Control groups had SCI and a unilateral hindlimb incision and nerve exposure only (group C) or a unilateral hindlimb disection and transection of both the tibial and peroneal nerves (group D). Three months after surgery, the proximal peroneal (group A) or proximal tibial (groups B, C, and D) nerves were electrically stimulated in vivo, and gastrocnemius force production was measured on both the operative and nonoperative hindlimbs. In addition, the distal tibial nerves from both the experimental and control-side hindlimbs were sectioned and stained with anti-neurofilament protein to determine total axon counts.
  
  
  RESULTS
  Mean gastrocnemius force return and mean axonal regeneration was 47% and 51%, respectively, for group A animals (n = 9), 68% and 73% for group B animals (n = 4), 97% and 99% for group C animals (n = 4), and 0 and 2% for group D animals (n = 4). A 1-way analysis of variance for independent samples yielded significant differences between groups A, B, and C for gastrocnemius force return and between all groups for axonal regeneration.
  
  
  CONCLUSIONS
  Paralyzed nerve transfer produces a mean of approximately 50% return of gastrocnemius force and axonal regeneration. Paralyzed nerve transfer combined with functional electrical stimulation is a viable method for reanimating denervated motor units in the setting of SCI.
authors.affiliation: Department of Orthopaedic Surgery, University Hospitals Case Medical Center, Cleveland, OH 44106, USA. Daniel.mastermd@gmail.com
authors.forename: Daniel
authors.initials: D
authors.lastname: Master
authors.forename: Thomas
authors.initials: T
authors.lastname: Cowan
authors.forename: Sreenath
authors.initials: S
authors.lastname: Narayan
authors.forename: Robert
authors.initials: R
authors.lastname: Kirsch
authors.forename: Harry
authors.initials: H
authors.lastname: Hoyen
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D004558:Electric Stimulation; D004576:Electromyography; D008853:Microscopy; D023421:Models, Animal; D009121:Muscle Denervation; D018482:Muscle, Skeletal / Q000294:innervation; D009416:Nerve Regeneration; D016067:Nerve Transfer / Q000379:methods*; D010543:Peroneal Nerve / Q000601:surgery*; D051381:Rats; D011916:Rats, Inbred F344; D013119:Spinal Cord Injuries / Q000601:surgery; D013979:Tibial Nerve / Q000601:surgery*