title: Human vagus nerve branching in the cervical region.
abstract: BACKGROUND
  Vagus nerve stimulation is increasingly applied to treat epilepsy, psychiatric conditions and potentially chronic heart failure. After implanting vagus nerve electrodes to the cervical vagus nerve, side effects such as voice alterations and dyspnea or missing therapeutic effects are observed at different frequencies. Cervical vagus nerve branching might partly be responsible for these effects. However, vagus nerve branching has not yet been described in the context of vagus nerve stimulation.
  
  
  METHODS
  Branching of the cervical vagus nerve was investigated macroscopically in 35 body donors (66 cervical sides) in the carotid sheath. After X-ray imaging for determining the vertebral levels of cervical vagus nerve branching, samples were removed to confirm histologically the nerve and to calculate cervical vagus nerve diameters and cross-sections.
  
  
  RESULTS
  Cervical vagus nerve branching was observed in 29% of all cases (26% unilaterally, 3% bilaterally) and proven histologically in all cases. Right-sided branching (22%) was more common than left-sided branching (12%) and occurred on the level of the fourth and fifth vertebra on the left and on the level of the second to fifth vertebra on the right side. Vagus nerves without branching were significantly larger than vagus nerves with branches, concerning their diameters (4.79 mm vs. 3.78 mm) and cross-sections (7.24 mm2 vs. 5.28 mm2).
  
  
  CONCLUSIONS
  Cervical vagus nerve branching is considerably more frequent than described previously. The side-dependent differences of vagus nerve branching may be linked to the asymmetric effects of the vagus nerve. Cervical vagus nerve branching should be taken into account when identifying main trunk of the vagus nerve for implanting electrodes to minimize potential side effects or lacking therapeutic benefits of vagus nerve stimulation.
authors: Institute of Anatomy, University of Leipzig, Faculty of Medicine, Leipzig, Germany.
authors: Niels
authors: N
authors: Hammer
authors: Department of Neurosurgery, University Clinic of Leipzig, Faculty of Medicine, Leipzig, Germany.
authors: Juliane
authors: J
authors: Glätzner
authors: Institute of Anatomy, University of Leipzig, Faculty of Medicine, Leipzig, Germany.
authors: Christine
authors: C
authors: Feja
authors: Department of Cardiology, University Clinic of Leipzig, Faculty of Medicine, Leipzig, Germany.
authors: Christian
authors: C
authors: Kühne
authors: Department of Neurosurgery, University Clinic of Leipzig, Faculty of Medicine, Leipzig, Germany.
authors: Jürgen
authors: J
authors: Meixensberger
authors: Institute of Anatomy, University of Leipzig, Faculty of Medicine, Leipzig, Germany; Department of Neurosurgery, University Clinic of Leipzig, Faculty of Medicine, Leipzig, Germany.
authors: Uwe
authors: U
authors: Planitzer
authors: Department of Orthopedic, Trauma and Reconstructive Surgery, University Clinic of Leipzig, Leipzig, Germany.
authors: Stefan
authors: S
authors: Schleifenbaum
authors: Institute of Anatomy, University of Kiel, Kiel, Germany.
authors: Bernhard N
authors: BN
authors: Tillmann
authors: Department of Neurosurgery, University Clinic of Leipzig, Faculty of Medicine, Leipzig, Germany.
authors: Dirk
authors: D
authors: Winkler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D009333:Neck / Q000294:innervation*; D014019:Tissue Donors; D014630:Vagus Nerve / Q000033:anatomy & histology* / Q000166:cytology