Vagal Nerve Stimulation (VNS)
Vagal nerve stimulation (VNS) is a chronic treatment for chronic depression that has not responded to other, more common treatments. A vagus nerve stimulation device is not unlike a pacemaker: it is small and implanted beneath the skin. The implanted device works by sending regular, mild pulses of electrical energy to stimulate the vagus nerve, which extends from the brainstem to the abdomen, lessening the symptoms of chronic and recurring depression.
The vagus nerve is a part of the involuntary nervous system and controls unconscious body procedures, such as keeping the heart rate constant and controlling food digestion. It is the main communicator between the body and the brain.
Conditions we treat with VNS include:
- Treatment-resistant depression
Surgery is needed to implant the vagus nerve stimulation device. Usually, the implant surgery takes about one to two hours. Patients typically receive general anesthesia during the implant surgery; sometimes, local anesthesia is used for the surgery. You may or may not stay in the hospital overnight following the implant surgery.
In order to implant the device, a surgeon creates one small incision on the left side of the neck, and a second incision below the collarbone (either in the chest or the armpit). Once the two incisions are made, a ‘lead’ is passed under the skin, linking the two incisions. The surgeon attaches the lead to the left vagus nerve in the neck. The other end of the lead is plugged into the generator (the implant). The generator is implanted in the incision made below the collarbone. Once the lead is attached to the vagus nerve, the lead is connected to the generator, and the generator is implanted, the surgeon closes the incisions. After implantation, some patients experience hoarseness, difficulty swallowing, headache, neck pain, and other minor side effects.
The implant is usually turned on approximately two weeks after surgery at a doctor’s office visit. The doctor will program the implanted generator to send electrical pulses to the vagus nerve at specific frequencies and strengths. Usually, the doctor will start at a low electric strength and increase the strength gradually.
It is possible to reverse the operation and remove the VNS system if a patient wants it removed. The removal of the pulse generator and lead is done via a surgical procedure.
Individuals for whom VNS is effective will see their symptoms start to improve after six months. Symptoms will generally continue to improve for up to two years, and will then level off. Many individuals with a VNS implant continue to take antidepressant medication after receiving the implant.