title: Early sensory protection in reverse end-to-side neurorrhaphy to improve the functional recovery of chronically denervated muscle in rat: a pilot study.
abstract: OBJECTIVE
  Early innervation by sensory nerves has been proposed to prevent atrophy of chronically denervated muscle, but conventional end-to-end (ETE) neurorrhaphy has been demonstrated to have adverse effects on muscle contractile function. The aim of the present study was to investigate the potential for modified sensory nerve protection in reverse end-to-side (ETS) neurorrhaphy as a way of improving the functional recovery of denervated muscle.
  
  
  METHODS
  Four groups of rats underwent surgical denervation of the tibial nerve projecting to the right hindlimbs (Group 1, unprotected controls; Group 2, positive control [immediate repair without delayed denervation]; Group 3, ETS protected; and Group 4, ETE protected). The proximal and distal stumps of the tibial nerve were ligated in all animals except for those in the immediate-repair group. Other animals underwent denervation without sural nerve protection, or with ETE or ETS neurorrhaphy. The ETE- and ETS-protected and unprotected groups underwent an additional surgery in which the trimmed proximal and distal tibial nerve stumps were sutured together. After 3 months of recovery, the tibial function index was determined, and electrophysiological, histological, and morphometric parameters were assessed.
  
  
  RESULTS
  Significant muscle atrophy was observed in the unprotected group, while a well-preserved ultrastructure was observed for the gastrocnemius muscle in the ETE- and ETS-protected groups. Enhanced recovery in the ETS-protected group was indicated by the tibial function index, motor nerve conduction velocity, muscle contractile force tests, and the histological results. In contrast, early sensory nerve protection in ETE neurorrhaphy impaired the recovery of the regenerated axons and diminished the contractile force of the denervated muscle.
  
  
  CONCLUSIONS
  Early sensory protection in reverse ETS neurorrhaphy is an effective method for improving the functional recovery of chronically denervated muscle following peripheral nerve injury in rats.
authors.affiliation: Department of Trauma and Orthopaedics, Peking University People's Hospital, Beijing, China.
authors.forename: Qingtian
authors.initials: Q
authors.lastname: Li
authors.forename: Peixun
authors.initials: P
authors.lastname: Zhang
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Yin
authors.forename: Na
authors.initials: N
authors.lastname: Han
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Kou
authors.forename: Baoguo
authors.initials: B
authors.lastname: Jiang
mesh_terms: D000818:Animals; D005260:Female; D009119:Muscle Contraction / Q000502:physiology; D009121:Muscle Denervation; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology / Q000648:ultrastructure; D009416:Nerve Regeneration; D009431:Neural Conduction / Q000502:physiology; D019635:Neurosurgical Procedures / Q000379:methods*; D010865:Pilot Projects; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D011984:Sensory Receptor Cells / Q000502:physiology*; D016138:Walking / Q000502:physiology
keywords: AChR = acetylcholine receptor; ETE = end-to-end; ETS = end-to-side; MNCV = motor nerve conduction velocity; PBS = phosphate-buffered saline; TFI = tibial function index; babysitter technique; end-to-side neurorrhaphy; muscle denervation; muscle reinnervation; nerve regeneration; peripheral nerve