Vagal nerve stimulation is indicated in patients with intractable epilepsy, treatment-resistant depression, drug-refractory hypertension and cardiac failure. This patient had intractable epilepsy, with poor control on four different anti-epileptic medications. Her initial VNS lasted 10 years and was recently replaced. She had a significantly improved lifestyle once she had a VNS implanted.

There is ongoing research to treat chronic headaches and intractable pain, rheumatoid arthritis, inflammatory bowel disease, bipolar disorder, obesity and Alzheimer's disease.

The pulse generator (which also houses the battery) is implanted within the left-sided infraclavicular subcutaneous soft tissues. A single or dual lead then ascends to the mid-left neck, with terminal electrodes that are placed on or near the left vagus nerve.

The right vagal nerve is not usually utilised due to its greater number of cardiac efferent fibres whose stimulation may result in more frequent adverse cardiac complications.

When treating drug-refractory hypertension and cardiac failure the VNS may be implanted within the right anterior chest wall soft tissues, with one lead tip within the right ventricle(sensing electrode) and the second lead (stimulating electrode) around the right vagal nerve.

So assessing the position of the leads may allude to the nature of the treatment between cardiac and non-cardiac.

Newer VNS devices are nowadays MRI conditional and limitations need to be strictly followed to avoid disasters and adverse events. Always enquire fully about the device prior to any MRI scan examination especially if it's an "old" device that may not be MRI conditional. Device settings are usually recorded and the device is usually interrogated and programmed by the treating clinicians prior to and after MRI studies.

Warning:

VNS patients often carry a small clip-on magnet to activate and deactivate their devices. Should this be inadvertently taken into the MR scanning room, it may result in an unexpected and potentially harmful projectile incident. (Images of the therapy magnet have been uploaded above).

Disclosure: I, Ashesh I Ranchod, have no actual or potential ethical or financial conflict of interest in relation to this device. This case is not intended to be a personal endorsement or recommendation of this product