Steve McChrystal , TN Patient

His Personal "Stimulator" Story

Note: I am an engineer, not a medical professional. Any suggestions I make should be reviewed by your doctor.

Following a series of sinus infections, I had surgery on my maxillary sinuses in 1987. Part of the second division of the trigeminal nerve was damaged, leaving me with a ache just left of my left nostril. They said it would go away... Subsequent procedures spread the pain to my jaw and cheek. I've been on and off of opioids a number of times. I've now had 24 general anesthesia surgeries, mostly in the last 20 years, mostly either for sinus infection or pain problems.

In 1993 I had an RF rhizotomy by a doctor at Stanford. The procedure uses a small probe inserted into the gasserian ganglion (The trigeminal nerve passes through the skull to the gasserian ganglion, where it splits into its three divisions), which heats up and destroys the targeted part of the nerve. It eliminated the pain for six months only, and left me with AD, including numbness from my cheek to the top of my scalp, burning around my eye, ache in the orbit, and damage to the corneal nerve, resulting in chronic dryness/blurring and infection.

I don't recommend the procedure. He said the eye pain would go away... Instead, it gradually increased over the years to equal or exceed my cheek and jaw pain.

Some years before, I had a neck problem and used a TENS (Transcutaneous Nerve Stimulator) for pain in my shoulder and arm. I decided to try it on my face, placing one electrode just below my eye and the other just left of my mouth. I cranked it up and actually got some relief ! I also got some funny looks going into the office with a pair of electrodes and wires hanging from my face. But it increased my confidence in electrical stimulation.

I worked as an electrical engineer for a large electronic company based in Munich, Germany, and traveled there regularly.  I contacted Dr. Ulrich Steude at the University of Munich. He implanted a gasserian stimulator which was completely effective for the AFP, but not so much for the AD. What is a Gasserian Stimulator ? A small electrode can be inserted into the ganglion through an incision in the cheek, and then threaded down the neck to a generator implanted in the upper chest. This procedure underwent clinical trials in the U.S. in the early 1990's. The results were mixed, with some difficulties in keeping the electrode in place.

Medtronic, the maker of the device, decided not to seek FDA approval for the procedure. In Germany and elsewhere, it is a common tool for the treatment of facial pain. Dr. Steude has done hundreds of cases and I have been involved in directing a few patients to Munich for the procedure. In 1995, the stimulator implant cost about $17,000. In the days of more benevolent insurance companies, they picked up the bill. I returned in 2002 to have the generator replaced. The system became infected and the next chapter began. Note: Any neurostimulator can become infected, during and after implantation. The usual solution is for the whole system to be removed, wait for the infection to clear, then try again.

I met a Stanford Hospital and Medical School doctor at a TNA sponsored talk on Motor Cortex Stimulation. I made an immediate appointment, and in 2003 he removed the Gasserian Stimulator and implanted a Motor Cortex Stimulator. Ordinarily, the MCS implant is a two or three day process, with the craniotomy and placement of the electrodes on the surface of the dura (dura mater - the tough membrane that encloses the brain and spinal cord) in one procedure, then testing with the wires exposed and the patient awake, then if successful, implantation of the generator/battery in a second operation. My doctor placed the generator in my upper chest; other doctors run the wire down to the generator in the abdomen. Because of the low conductivity of the dura, leading to short battery life (one year typical), he replaced a section of the dura with bovine pericardial tissue (the membrane that surrounds a cow's heart) Moo!. He also placed two strips of four electrodes on the dura, one over the motor gyrus (a ridge of the cortex), and another over the adjacent sensory gyrus. Because I had the gasserian electrode in place, MRI could not be used to map the cortex, a CT was used instead. Each of the eight electrodes can be programmed as positive or negative, allowing current to flow along the motor gyrus, which is the traditional (gyral) mode, or from the motor gyrus across to the sensory gyrus (trans-sulcal).

My case was not typical. With the removal of the infected gasserian unit and the implantation of the MCS, I had four operations in three weeks. After the implant of the electrodes, there was some inflammation and I was in the ICU for four days. I was aphasic - I could not speak.

I could form the concept of what I wanted to say but the words wouldn't come. It was very, very frightening. I finally regained my speech. In testing the stimulator in the hospital, I had two seizures. In all, it was a miserable experience. Part of the problem was due to the infection of the gasserian system. We had hoped to keep the gasserian electrode in place to gain its benefits, but after removal of the generator, the infection persisted, so it had to be removed. I have divots, creases and ridges over much of the right side of my skull, but I have plenty of hair to cover it. My barber has special laser-guided terrain-following shears to trim that side (just kidding).

Note: MRI uses strong magnetic fields to develop an image. These fields are capable of inducing current into any metallic element in the area being imaged, causing heating or movement of the metal. For this reason, having a neurostimulator, including the electrodes and the generator, rules out the use of MRI near the system. If the generator is placed in the upper chest, MRI of the lower abdomen may be possible. Consult your surgeon.

Over the following months, I had a lot of difficulty getting adequate pain relief from the unit. It was programmed for gyral mode, using just the electrodes on the motor gyrus. I was allowed full control over the parameter settings (voltage, the amount of current in each pulse, pulse width, and rate-how many pulses per second). If I set the levels too low, I got no pain relief. If set too high, the muscles in the orbit of my eye would cramp painfully. Finally, we switched to trans-sulcal mode, with the current flowing from the motor gyrus, down into the crease (sulcus) in the brain, then up to the sensory side. This provided good relief, though still subject to cramping. At this point, we moved from Santa Clara, California to Phoenix, a small town in southern Oregon. I had retired, disabled, and we left the congestion and sprawl behind. We bought a lot and built a house.

In the first six months, I had two seizures. It cost me my driving privileges for six months. The first happened after I stopped taking dilantin (nausea) and went to sleep with the stimulator at a high setting. The second happened after I switched to Keppra and went to sleep with a high setting. Seeing a trend, I learned that your seizure threshold drops when you sleep, and that you can have seizures with or without anti-seizure medication. My solution was this: GRADUALLY increase the voltage until I feel a rhythmic contraction in the muscles in my face. If left like this, a seizure would occur. Then I immediately back the voltage down one volt. DO NOT TRY THIS WITHOUT HAVING SOMEONE PRESENT WHO CAN IMMEDIATELY TURN THE STIMULATOR OFF! During the day, I could turn it up a bit if really necessary.

Everything was OK for a couple of years. I was rapidly weaning off opioids and was active in planning and building the new house. I had the generator replaced twice, finally with a rechargeable device. But I was getting much less pain control, regardless of the parameter settings. Tolerance had developed. Also, I could not induce a seizure, even at the highest settings. My brain had adapted. I spent most of six months in bed with a pillow over my face. In Sept. 2006 I went back to my California doctor who added more electrode arrangements (programs). He gave me full control over selection of the programs and the parameters, which normally he would not do with patients.

My background as an engineer and history with stimulators, plus the six hour driving distance from home made us comfortable with that arrangement. The result was that switching back to gyral mode was successful in reducing my pain back to earlier levels. I don't know how long this will continue, but I'm taking advantage of the situation while it lasts. I'm far from being pain free, but I'm functional for a good part of the day.

Frankly, I didn't think the re-programming was going to work, and I was considering options. Deep Brain Stimulation was proposed by my doctor, though he gave it only a 50% chance of success, and there are tolerance problems associated with this procedure as well. It is used mostly for treating Parkinson's and gets mixed reviews for the treatment of pain from the medical community.  Gamma Knife has been successful on a couple of AD patients. I was seriously planning on DBS, but for now, I don't have to think about it. I was also considering returning to Germany to have the gasserian electrode re-implanted. So that's where I am today.

Regarding cost, I have Medicare because of my disability, and a supplement. All costs of the initial implant and subsequent generator changes were completely covered.

If all of this so far has sounded a bit clinical, it is because I wanted to get the relevant facts down. There is certainly a human side. I had to abandon a career as an integrated circuit designer and software developer that I born to do and truly loved. I worked for many years working six hours in the office, home for a two hour nap, then four more hours from home, then bed, all the while taking large amounts of drugs.

I have three adult children who grew up with a father in pain who was often unreachable. But I worked long enough to see them through college. I have a wife who was diagnosed with MS about the same time I developed the pain problems. She needs support that I can't always provide. I've had 20 years of therapy. And seizures are terrifying. Being semi-conscious and out of control is HELL. I remember every second.

On the other hand, I have love and support and am financially OK. I love the outdoors and find a good bike ride to be better than any chemical anti-depressant (I've tried them all). Strenuous exercise generates endorphins which are good for 4 to 6 hours of relief and generally raise your pain threshold. I've been able to share my experiences with other people in pain and think I've been helpful. I just turned 57 and have a lot of life ahead of me and though I've considered giving up, it is not the time. I try not to whine.

I do take meds. I've taken baclofen and clonidine since the rhizotomy and have been on Neurontin (gabapentin) for six years. I tried Lyrica (pregabalin), which is Pfizer's newer proprietary drug, but it didn't do much or me. One of the side effects of Neurontin for me is burning feet, which limits my consumption to 1800 mg. per day.

My last and probably most important comment is this:

DO NOT BE INTIMIDATED by your own lack of training in medicine. BE ASSERTIVE, politely but persistently, and ask lots of questions of your doctors. If they don't have the patience to explain things, then you should FIND ANOTHER DOCTOR. MCS often needs a while to get adjusted correctly, and chronic pain needs support beyond the surgery. I'd hate to cast a broad generalization, but most surgeons are procedure-oriented. It is a very demanding profession and they, more than most physicians, develop a barrier between themselves and their patients, probably to prevent emotional involvement in the losing battles. Once the job is done, success or failure, some lose interest in the patient, particularly in the latter case.

Posted 11-09-06