title: Specific branches of hypoglossal nerve to genioglossus muscle as a potential target of selective neurostimulation in obstructive sleep apnea: anatomical and morphometric study.
abstract: OBJECTIVE
  To determine the ideal implantation site for selective tongue neurostimulation in obstructive sleep apnea, anatomy of the distal branching of the hypoglossal nerve (HGN) was revisited.
  
  
  METHODS
  The HGN distal course and intramuscular distribution to the tongue muscles were studied in 17 embalmed and 5 fresh heads (age 60-98, BMI 20-35). Medial branches supplying selectively the genioglossus (GG) muscle were identified. Then, the distinct bundles entering the oblique (GGo) and horizontal (GGh) parts of the GG were located. Morphometric data were compared to similar measurements made on MRI sections from 12 patients (age 43-71, BMI 18-47).
  
  
  RESULTS
  The key facts relevant to optimize stimulation and electrode design are the following: the mean width of both GG muscles in embalmed and fresh cadavers was 20.7 ± 2.9 and 21.4 ± 5 mm, respectively; it is significantly (p < 0.05) superior to the MRI value of 18.26 ± 2.0 mm. Selective nervous branches for GGh and GGo were located at 52 ± 8% of hyoid bone-mandibular symphysis distance and at 5.8 ± 1.1 mm from the inferior border of the GG muscle. The surface of stimulation is a 4.4 ± 1.1 × 6.9 ± 3.8 mm ellipse.
  
  
  CONCLUSIONS
  According to our observations, the optimal selective or supra-selective stimulation of the tongue protractor muscles can be performed on the lateral surface of the GG at roughly equal distance between the mandibular symphysis and the hyoid bone, at a depth of about 0.6 cm above the GG lower border.
authors.affiliation: Pôle de Morphologie (MORF), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Avenue E. Mounier 52, Bte B1.52.04, 1200, Brussels, Belgium.|Pôle de Chirurgie Expérimentale et Transplantation (CHEX), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Avenue Hippocrate 55 bte B1.55.04, 1200, Brussels, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Delaey
authors.affiliation: Pôle de Chirurgie Expérimentale et Transplantation (CHEX), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Avenue Hippocrate 55 bte B1.55.04, 1200, Brussels, Belgium.|Department of Plastic and Reconstructive Surgery, Université Catholique de Louvain, Cliniques Universitaires St-Luc, Avenue Hippocrate 10, 1200, Brussels, Belgium.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Duisit
authors.affiliation: Pôle de Morphologie (MORF), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Avenue E. Mounier 52, Bte B1.52.04, 1200, Brussels, Belgium.
authors.forename: Catherine
authors.initials: C
authors.lastname: Behets
authors.affiliation: Department of Radiology and Medical Imaging, Université Catholique de Louvain, Cliniques Universitaires Saint-Luc, Avenue Hippocrate 10, 1200, Brussels, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Duprez
authors.affiliation: Pôle de Chirurgie Expérimentale et Transplantation (CHEX), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Avenue Hippocrate 55 bte B1.55.04, 1200, Brussels, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Gianello
authors.affiliation: Pôle de Morphologie (MORF), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Avenue E. Mounier 52, Bte B1.52.04, 1200, Brussels, Belgium. benoit.lengele@uclouvain.be.|Department of Plastic and Reconstructive Surgery, Université Catholique de Louvain, Cliniques Universitaires St-Luc, Avenue Hippocrate 10, 1200, Brussels, Belgium. benoit.lengele@uclouvain.be.
authors.forename: Benoît
authors.initials: B
authors.lastname: Lengelé
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D006801:Humans; D007002:Hypoglossal Nerve / Q000033:anatomy & histology*; D058542:Implantable Neurostimulators; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology / Q000628:therapy
keywords: Genioglossus muscle; Hypoglossal nerve; Obstructive sleep apnea therapy; Supra-selective neurostimulation