title: Hypoglossal-facial nerve "side"-to-side neurorrhaphy for persistent incomplete facial palsy.
abstract: OBJECTIVE
  Hypoglossal-facial nerve neurorrhaphy is a widely used method for treating complete facial palsy. However, the classic surgical procedure using a "side"-to-end neurorrhaphy is not suitable for incomplete facial palsy (IFP), because sectioning of the facial nerve for neurorrhaphy compromises remnant axons and potential spontaneous reinnervation. For the treatment of persistent IFP, the authors investigated in rats a modified method using hypoglossal-facial nerve "side"-to-side neurorrhaphy.
  
  
  METHODS
  An IFP model was created by crushing the facial nerve and then ligating the injury site to limit axonal regeneration. After 9 weeks, rats with IFP were submitted to hypoglossal-facial nerve "side"-to-side neurorrhaphy: The gap between the 2 nerves was bridged with a predegenerated peroneal nerve graft, which was sutured to only one-half of the hypoglossal nerve and to the remnant facial nerve through a small window created by removing the epineurium, thus preserving regenerating facial axons.
  
  
  RESULTS
  Four months after repair surgery, double innervation of the target whisker pad by hypoglossal and facial motor neurons was supported by the recording of muscle action potentials and their retrograde labeling. Regenerated hypoglossal and facial motor neurons effectively participated in the reinnervation of the whisker pad, significantly improving facial symmetry without evident synkinesis, compared with rats that underwent IFP without hypoglossal-facial nerve neurorrhaphy.
  
  
  CONCLUSIONS
  This study demonstrates that hypoglossal-facial nerve "side"-to-side neurorrhaphy with a predegenerated nerve graft can lead to rapid functional benefits for persistent IFP without compromising the remnants of facial axons, thus providing a proof-of-feasibility for further studies in humans.
authors.affiliation: Beijing Neurosurgical Institute;
authors.forename: Hong
authors.initials: H
authors.lastname: Wan
authors.forename: Liwei
authors.initials: L
authors.lastname: Zhang
authors.forename: Dezhi
authors.initials: D
authors.lastname: Li
authors.forename: Shuyu
authors.initials: S
authors.lastname: Hao
authors.forename: Jie
authors.initials: J
authors.lastname: Feng
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Oudinet
authors.forename: Michael
authors.initials: M
authors.lastname: Schumacher
authors.forename: Song
authors.initials: S
authors.lastname: Liu
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001369:Axons; D004576:Electromyography; D005154:Facial Nerve / Q000601:surgery*; D020220:Facial Nerve Injuries / Q000150:complications / Q000601:surgery*; D005158:Facial Paralysis / Q000209:etiology / Q000601:surgery*; D007002:Hypoglossal Nerve / Q000601:surgery*; D008297:Male; D009416:Nerve Regeneration / Q000502:physiology; D019635:Neurosurgical Procedures / Q000379:methods*; D051381:Rats; D011916:Rats, Inbred F344