Implanting the VNS battery in a patient and connecting it to the vagus nerve takes about an hour. It is usually done under general anesthesia, though local anesthesia is sometimes used. The operation can be done on an in-patient or out-patient basis.
The surgeon makes two small incisions — one in the neck to gain access to the vagus nerve, and one below the collarbone in the chest wall or armpit.
The surgeon places the VNS pulse generator into a surgically-made “pocket” under the skin of the patient’s chest and threads a plastic tube containing the electrodes from the neck to the generator in the chest. He or she then gently wraps the flexible ends of silicone-coated electrodes around the vagus nerve.
Programming the Device
Some doctors turn on the VNS device immediately after surgery. Others prefer to start the stimulation during the check up visit afterwards. Doctors program the device to deliver pulses of electrical stimulation automatically, 24 hours a day.
A typical “dose” is about 30 seconds on and five minutes off, but settings may vary. The device continues the cycle until the neurologist re-programs it or until the battery runs out — usually in about six years.
At that time another surgical procedure (which only involves the chest) can be done to replace the battery, usually with a local anesthetic.