New vagus nerve stimulation lead and implantable pulse generator placement

Scenario

A 27-year-old man had suffered from epilepsy since the age of 8. He had two types of seizures ultimately, one with generalized tonic-clonic behavior and the other with staring and brief rhythmic chewing type movements followed by slight left arm twitching and abnormal posturing. For a few years in adolescence, he had no seizures, but by the time he was in college in his later teens, they recurred, forcing him to drop out of school and he was never able to finish his degree. Unfortunately, over the next 7 years to the present, he has had an escalating frequency of seizures, briefly decreasing in frequency with some of the medication alterations that have taken place many times over the years, only to resume their typical frequency after a few weeks or months on the new medication regime. At present, he has the generalized seizures every few months while the other type occurs a few times each week. On occasion, he can have even three in a day, while at times, he has managed for 2–3 weeks without any seizures. Maintaining employment with little training has been difficult. Relationships also have been difficult to maintain, and he has n’t been able to drive in many years.

He has been brought into an epilepsy-monitoring unit several times over the years and found to have most often left temporal lobe onsets but with rapid spread to the right, and, on some occasions, onsets were thought to be from the right temporal region. He is right-handed, and discussion with him regarding intracranial monitoring and potential resection of brain tissue if a focus is found has left him feeling reticent about proceeding. He is reluctant to risk language function if the resection is from the left temporal area (which seems to be the most likely predominant focus location). Other options were discussed including vagus nerve stimulation, deep brain stimulation in the anterior thalamus, and responsive neural stimulation placement (which would require intracranial monitoring). More discussions with the patient’s parents and the patient himself took place, and eventually it was decided that he would try vagus nerve stimulation first. An appointment was made with the surgeon, and risks and potential benefits were described, including infection, displacement or breakage, hematoma, hoarseness during stimulation, damage to the carotid or jugular vessels or other neck tissues, and the beneficial possibility (especially over time) that seizures could be reduced in frequency and severity and may be eliminated entirely, although this was less than a 10% chance. On the other hand, he had been tried on over six different antiepileptic medications over the years, and a preponderance of data suggests that after only three different medications, his chances of being seizure free are less than 5% if further medications are tried. He agreed to move forward with the implantation, and surgery was scheduled.

• Variation : The patient has focal motor seizures -- While there has not been identified any particular seizure type that responds best to vagus nerve stimulation per se, focal motor seizures are perhaps less likely to respond well. On the other hand, vagus nerve stimulation is not contraindicated, although identification of the focus is usually possible, and responsive neural stimulation may be better in this setting overall as the recording and stimulation electrodes can be usually placed very close to the focus and they can be positioned relatively noninvasively because the onset is often cortical.

• Variation : The patient is physically and cognitively disabled with frequent generalized seizures and subsequent injuries and difficult to manage within their care facility at least partly related to the frequent seizures -- This type of situation is often one of the most rewarding and beneficial indications for vagus nerve stimulation. Getting the patient to agree to behave for the surgery workup, placement of the IV, and waiting in the preoperative area are all part of the challenge in these patients. Sometimes it is very easy and everything proceeds smoothly, and other times, it can be so difficult the surgery cannot be accomplished, although such cases are more rare. An important and often critical detail in getting such cases done expeditiously is having the legal guardian or power of attorney available at the time for consent by both surgery and anesthesia services. This should be arranged ahead of time and confirmed prior to the day of surgery.