title: Hypoglossal-facial anastomosis (HFA) over a 10 mm gap bridged by a Y-tube-conduit enhances neurite regrowth and reduces collateral axonal branching at the lesion site.
abstract: OBJECTIVE
  The outcome of severe peripheral nerve injuries requiring surgical repair (transection and suture) is usually poor. Recent work suggests that direct suture of nerves increases collagen production and provides unfavourable conditions for a proper axonal regrowth. We tested whether entubulation of the hypoglossal nerve into a Y-tube conduit connecting it with the zygomatic and buccal facial nerve branches would improve axonal pathfinding at the lesion site, quality of muscle reinnervation and recovery of vibrissal whisking.
  
  
  METHODS
  For hypoglossal-facial anastomosis (HFA) over a Y-tube (HFA-Y-tube) the proximal stump of the hypoglossal nerve was entubulated and sutured into the long arm of a Y-tube (isogeneic abdominal aorta with its bifurcation). The zygomatic and buccal facial branches were entubulated and sutured to the short arms of the Y-tube. Restoration of vibrissal motor performance, degree of collateral axonal branching at the lesion site and quality of neuro-muscular junction (NMJ) reinnervation were compared to animals receiving HFA-Coaptation (no entubulation) after 4 months.
  
  
  RESULTS
  HFA-Y-tube reduced collateral axonal branching. However it failed to reduce the proportion of polyinnervated NMJ and did not improve functional outcome when compared to HFA-Coaptation.
  
  
  CONCLUSIONS
  Elimination of compression by tightly opposed nerve fragments improved axonal pathfinding. However, biometric analysis of vibrissae movements did not show positive effects suggesting that polyneuronal reinnervation - rather than collateral branching - may be the critical limiting factor. Since polyinnervation of muscle fibers is activity-dependent and can be manipulated, the present findings raise hopes that clinically feasible and effective therapies after HFA could be soon designed and tested.
authors.affiliation: Department of Anatomy, Akdeniz University, Faculty of Medicine, Antalya, Turkey.
authors.forename: Umut
authors.initials: U
authors.lastname: Ozsoy
authors.forename: Bahadir Murat
authors.initials: BM
authors.lastname: Demirel
authors.forename: Arzu
authors.initials: A
authors.lastname: Hizay
authors.forename: Ozlem
authors.initials: O
authors.lastname: Ozsoy
authors.forename: Janina
authors.initials: J
authors.lastname: Ankerne
authors.forename: Srebrina
authors.initials: S
authors.lastname: Angelova
authors.forename: Levent
authors.initials: L
authors.lastname: Sarikcioglu
authors.forename: Yasar
authors.initials: Y
authors.lastname: Ucar
authors.forename: Doychin N
authors.initials: DN
authors.lastname: Angelov
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods*; D000818:Animals; D001012:Aorta, Abdominal; D001369:Axons / Q000473:pathology*; D004195:Disease Models, Animal; D005152:Facial Muscles / Q000294:innervation* / Q000503:physiopathology; D005154:Facial Nerve / Q000601:surgery*; D020220:Facial Nerve Injuries / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D007002:Hypoglossal Nerve / Q000601:surgery*; D008866:Microsurgery / Q000379:methods; D009416:Nerve Regeneration; D051381:Rats; D017208:Rats, Wistar; D019651:Plastic Surgery Procedures / Q000379:methods; D020127:Recovery of Function; D016896:Treatment Outcome