title: Functional motor nerve regeneration without motor-sensory specificity following end-to-side neurorrhaphy: an experimental study.
abstract: OBJECTIVE
  To evaluate the quality of regenerating myelinated axons and motor-sensory specificity in an end-to-side nerve repair model.
  
  
  METHODS
  We divided 20 rats into 3 groups: (1) end-to-side neurorrhaphy using the ulnar nerve as donor nerve and the musculocutaneous nerve as recipient nerve; (2) normal control; and (3) transected nerve with the stumps buried. At 5 months, we monitored the grooming test, the electrophysiological response, and the histologic changes in nerve and muscle.
  
  
  RESULTS
  Grooming recovered successfully, and electrophysiological investigations revealed that the target muscles had been reinnervated in the end-to-side group. The mean wet weight of the reinnervated biceps brachii muscle was 72% of the normal muscle, and the mean muscle fiber cross-sectional area of the reinnervated muscle was similar to the normal muscle. The implanted musculocutaneous nerve contained varying but satisfactory numbers of axons (end-to-side group: 596 ± 348 vs normal group: 1,340 ± 241). Acetylcholinesterase staining revealed a similar percentage of myelinated fibers in the musculocutaneous nerve (39%) and the biceps brachii branch of the musculocutaneous nerve (38%) in the end-to-side group. This was similar to the number of myelinated fibers in the donor ulnar nerve (37%).
  
  
  CONCLUSIONS
  The present study confirms that limited but functional reinnervation can occur on the basis of collateral sprouting of intact axons from the ulnar nerve. The motor-sensory specificity is not important.
authors: Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical College, Zhejiang, China.
authors: Qing
authors: Q
authors: Yu
authors: Zhong-Ke
authors: ZK
authors: Lin
authors: Jian
authors: J
authors: Ding
authors: Tao
authors: T
authors: Wang
authors: Yong-Long
authors: YL
authors: Chi
authors: Wei-Yang
authors: WY
authors: Gao
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001369:Axons / Q000502:physiology; D008297:Male; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation*; D009138:Musculocutaneous Nerve / Q000502:physiology / Q000601:surgery*; D009416:Nerve Regeneration / Q000502:physiology*; D019635:Neurosurgical Procedures; D051381:Rats; D017207:Rats, Sprague-Dawley; D018709:Statistics, Nonparametric; D014459:Ulnar Nerve / Q000502:physiology / Q000601:surgery*