10.23\ Vagal Nerve Stimulation

10.23.1  Discussion

Vagus nerve stimulation is an effective method for controlling intractable seizures, with up to 50% reduction in seizure frequency. The device consists of two electrodes and an anchor loop implanted in the left neck at the midcervical level posterolateral to the internal and common carotid arteries and medial to the internal jugular vein. The electrodes are connected to a gen-

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erator that is implanted beneath the infraclavicular subcutaneous tissues. Unlike with the right vagus nerve, left vagal stimulation does not affect cardiac function. The most common side effects of vagus nerve stimulation include sore throat and voice changes. Radiographs or CT may be performed to delineate the position and integrity of the electrodes (Fig. 10.116). The vagal nerve stimulators are considered MRI conditional and output currents should be programmed to 0 mA before entering the MRI suite.

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Fig. 10.116  Vagal nerve stimulator. Fontal neck radiograph (a) shows left vagus nerve lead in position (arrow). The pulse generator is partially shown in the left chest

region. Axial (b) and coronal (c) CT images show the components of the stimulator electrodes (arrows)