Human vagus nerve branching in the cervical region.

Yvette Tache,Niels Hammer,Bernhard N Tillmann,Christian Kühne,Stefan Schleifenbaum,Uwe Planitzer,Christine Feja,Dirk Winkler,Juliane Glätzner,Jürgen Meixensberger

doi:10.1371/journal.pone.0118006

Yvette Tache, Niels Hammer + Show 8 more

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https://doi.org/10.1371/journal.pone.0118006

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Abstract

BackgroundVagus 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.Materials and MethodsBranching 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.ResultsCervical 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).DiscussionCervical 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.

Highlights

Vagus nerve stimulation (VNS) is becoming an increasingly popular therapy for patients with refractory epilepsy [1,2,3,4,5,6,7,8] and psychiatric conditions such as depression [9,10]
Cervical vagus nerve branching was observed in 29% of all cases (26% unilaterally, 3% bilaterally) and proven histologically in all cases
Branching of the cervical vagus nerve (CVN) in the carotid sheath was observed in 29% of the donors (10/35), in 26% (9/35) unilaterally and in 3% (1/35) bilaterally (Fig. 1; Table 1)

Summary

Introduction

Vagus nerve stimulation (VNS) is becoming an increasingly popular therapy for patients with refractory epilepsy [1,2,3,4,5,6,7,8] and psychiatric conditions such as depression [9,10]. It is assumed to run lateral and parallel to the common carotid artery and with branching only in a very small number of cases [13,14,15] Against this widely accepted postulate, we experienced CVN branching as a common phenomenon when dissecting this anatomical region in body donors. Vagus nerve stimulation is increasingly applied to treat epilepsy, psychiatric conditions and potentially chronic heart failure. Vagus nerve branching has not yet been described in the context of vagus nerve stimulation

Results

Discussion

Conclusion