title: Motoneurons innervating facial muscles after hypoglossal and hemihypoglossal-facial nerve anastomosis in rats.
abstract: Hypoglossal-facial nerve anastomosis (HFA) is the most popular surgical procedure to reinnervate facial muscles after injury of the facial nerve. Section of the hypoglossus causes paralysis and atrophy of the hemi-tongue. In the attempt to overcome this consequence, the hemihypoglossal-facial nerve anastomosis (HHFA) has been proposed and only a half of the main trunk of the hypoglossus is connected to the distal stump of the facial nerve. In the rat, we have studied experimentally the anatomical nuclear changes after HFA and HHFA with the aim of establishing the quantitative motoneuron innervation of facial muscles obtained with each one of the two operative options. Horseradish peroxidase (HRP) injected in both types of anastomosis labeled not only hypoglossal motoneurons, but also facial motoneurons. HFA appeared to offer a significant quantitative motoneuron innervation higher than HHFA and then a higher probable better functional recovery. Both HFA and HHFA performed immediately after section of the facial nerve in rats did not result in a phenomenon of motor hyperinnervation. In our experimental model, the proximal facial nerve stump was coagulated at the stylomastoid foramen to avoid regeneration. Then, the labeled motoneurons into the facial nucleus could really be the expression of axonal projections from facial motoneurons to the hypoglossus nerve and facial muscles. No labeled motoneurons were seen contralaterally as we observed previously after section and repair of several nerves.
authors.affiliation: Center of Research on Regeneration in the Nervous System, Department of Neurosurgery, Catholic University School of Medicine, Rome, Italy. e.fernandez@rm.unicatt.it
authors.forename: Eduardo
authors.initials: E
authors.lastname: Fernandez
authors.forename: Liverana
authors.initials: L
authors.lastname: Lauretti
authors.forename: Luca
authors.initials: L
authors.lastname: Denaro
authors.forename: Nicola
authors.initials: N
authors.lastname: Montano
authors.forename: Francesco
authors.initials: F
authors.lastname: Doglietto
authors.forename: Federica
authors.initials: F
authors.lastname: Novegno
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Falchetti
authors.forename: Tommaso
authors.initials: T
authors.lastname: Tufo
authors.forename: Giulio
authors.initials: G
authors.lastname: Maira
authors.forename: Roberto
authors.initials: R
authors.lastname: Pallini
mesh_terms: D000714:Anastomosis, Surgical; D000818:Animals; D001369:Axons / Q000378:metabolism; D002452:Cell Count; D005152:Facial Muscles / Q000294:innervation*; D005154:Facial Nerve / Q000601:surgery*; D006735:Horseradish Peroxidase; D007002:Hypoglossal Nerve / Q000601:surgery*; D008297:Male; D023421:Models, Animal; D009046:Motor Neurons / Q000502:physiology*; D009416:Nerve Regeneration / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000502:physiology; D014278:Trigeminal Nuclei / Q000166:cytology / Q000378:metabolism
chemical_list: D006735:Horseradish Peroxidase