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DBS For Dystonia

DBS For Dystonia

CREATED May 2, 2014
FORT WORTH, Texas (Ivanhoe Newswire) - Dystonia is a movement disorder that affects about 300,000 Americans. Simple activities like walking, balancing, or even talking are hard for these patients. Now – a surgery that’s known for helping people with Parkinson’s is also helping those with dystonia.


Emma Horton is a little girl with a big personality.

“She lights up a room when she goes into it,” Cheryl Horton, Emma’s mom, told Ivanhoe.

Even though the 7-year-old can’t talk –she can communicate with her iPad.

“My favorite movie is Frozen,” Emma told Ivanhoe.

Emma has dystonia, a condition that causes her muscles to contract and spasm. Even the simplest tasks are a challenge.

“Just little things that you take for granted that a 7-year-old should be able to do, Emma was never able to do it,” Colby Horton, Emma’s dad, told Ivanhoe.

But today Emma is doing better than ever – thanks to deep brain stimulation, DBS for short.

“We’ve been very pleasantly surprised by her,” John Honeycutt, MD, Neurosurgeon, Cook Children’s Medical Center, told Ivanhoe.

Here’s how it works: electrodes are placed in the brain and wires connect them to batteries implanted in the chest. The device sends electrical pulses to affected parts of the brain – and “resets” them. The best part is Emma was able to have anesthesia and be asleep during the surgery.

“We used to keep the kids awake. They don’t have to be awake anymore,” Dr. Honeycutt said. “We saw immediately some of that undesired movement stop.”

Also, three months after DBS, Emma rode her bike for the first time.

Dr. Honeycutt said it typically takes six months or longer for patients with dystonia to see very good results after DBS. Emma is expected to improve even more. Although DBS is a promising treatment, it isn’t a cure. If patients have their device removed – their symptoms will likely return.

RESEARCH SUMMARY

BACKGROUND: Dystonia is a movement disorder characterized by involuntary contractions and spasms of muscles. These actions force the body into repetitive, often twisting, movements and awkward, irregular postures. Dystonia, which may affect a single body area or be generalized through multiple muscle groups, affects men, women, and children of all ages and backgrounds. (Source: http://www.mayoclinic.com)

SYMPTOMS: Dystonia typically develops in a slow and gradual fashion, with mild symptoms. It affects muscles that may be controlled voluntarily in normal instance; it does not affect smooth muscle, as is found in the heart and bladder. Patients may begin to experience cramps, jerky or spasmodic muscle actions and loss of control of parts or areas of their body. These may grow more severe and result in the distinctive twisting and awkward postures that most people associate with this condition. (Source: www.cedars-sinai.edu)

TREATMENT: Dystonia symptoms may be managed or alleviated by medication, Botulinum Toxin therapy, or surgery. Treatment has improved in recent years, due to successes with botulinum toxin (Botox, Myobloc) injections. Some forms of early-onset dystonia respond to levodopa and carbidopa (Parcopa, Sinemet) — a medication combination that increases brain dopamine, a neurotransmitter involved with muscle movement. Surgery is considered only in certain types of dystonia and when other treatments have not worked. With certain types of dystonia, surgeons can sever or remove the nerves controlling the contracted muscle. This may be done for eyelid dystonia (blepharospasm) or neck (cervical) dystonia. (Source:http://www.mayoclinic.com, www.cedars-sinai.edu)

NEW TECHNOLOGY: Dystonia may also be treated with a range of surgical options, specifically deep brain stimulation (DBS). In DBS, leads are implanted deep in the brain and electrical stimulation is targeted at key sites to try to control shaking, stiffness and loss of muscle control. To modulate the effect of the treatment, doctors can adjust the frequency and intensity of electrical pulses. Risks include infection, stroke-like problems, such as weakness or paralysis, and possible speech difficulties. Now, doctors can perform the surgery to implant the stimulator when the patient is asleep. (Source: http://www.mayoclinic.com, Dr. John Honeycutt)

INTERVIEW

John Honeycutt, M.D., Pediatric Neurosurgeon at Cook Children’s Medical Center, talks about treating pediatric dystonia with deep brain stimulation.

What is pediatric dystonia?

Dr. Honeycutt: Dystonia is an abnormal movement that kids or adults can get. It’s basically where both agonist and antagonist muscles work at the same time. So if you want to stretch out and grab something, some of your muscles fire and some of them your muscles relax, allowing you to do it smoothly. With dystonia they all fire and so you can’t quite get your arms, or your hands, or your legs, or your speech to do exactly what you want them to do.

What causes it?

Dr. Honeycutt: We have sort of two separate kinds. You have what’s called primary, which is due to genetics, so you have the wrong genes that cause it to occur. Then we also have secondary dystonia that’s caused by some sort of injury to the brain. From our patient population the most common is cerebral palsy from injury after birth is what we see. That they can be trauma, infections, and all other sources that can also cause it.

What’s the difference between cerebral palsy and dystonia then?

Dr. Honeycutt: Cerebral palsy is a wastebasket term for developmental delay because of a previous brain injury. And like I said most of our patients had brain injuries from either while in utero or during childbirth or soon after childbirth. That’s our most common scenario, we see that. So not all cerebral palsy patients have dystonia and not necessarily all dystonia patients have cerebral palsy.

Is it something that you live with or do you die from it?

Dr. Honeycutt: Generally you live with it although some of our patients have such horrible dystonia they have complications secondary to that and that can lead to a shortened lifespan or a hastened death. Problems with breathing, problems with the wound breakdowns, it’s hard to just take general care of them. It’s hard to bathe them, it’s hard to dress them; it makes life really difficult.

What’s the difference between secondary dystonia and primary?

Dr. Honeycutt: Primary dystonia is really a genetic dystonia, and is one of our most common ones. It also happens to respond the best to deep brain stimulator. As a matter of fact, if we have a patient that has DYT1 we won’t wait very long before we put a deep brain stimulator in. We’ll try some medication, try some things, but as soon as we know it’s progressing, we’ll go ahead and recommend a deep brain stimulator because it really seems to do a nice job of reversing it.

Why would it work for one and not the other?

Dr. Honeycutt: It’s just the way the brain’s wired and that’s one of things that people are looking into.

But the hard part about deep brain stimulation is that you have to keep the kids awake during surgery, right?

Dr. Honeycutt: What we’re doing here recently with our new ClearPoint system is what we call sleep DBS. So now they’re under general anesthesia so they don’t have to be awake anymore. It’s hard enough for adults to do this; you can imagine being a 7-year-old or a 12-year-old and having anxiety about being in the operating room. Being told they’re having brain surgery while being awake is really a terrifying proposition.

Is it something that stays on all the time? And what if 10 years down the road, they turn it off: does the dystonia come back?

Dr. Honeycutt: That’s one of the things that were still looking into. Mostly the answer is yes, but there are some occasional people that when you turn it off, they seem to be fine. So you wonder, is it rewiring the brain well enough so that they no longer need it? But for the majority of patients when they start turning it off, it gets worse. We see that all the time with our kids; the batteries wear out and they don’t know it, and all of a sudden they start getting worse. They come and see us, we check them out, and the batteries have gone dead. So they still require this long term.

How long do the batteries last?

Dr. Honeycutt: It depends on how high it’s turned up. If it’s turned up really high it doesn’t last very long. And unfortunately for a lot of our kids that are in for dystonia they have it turned up really high, so the batteries run out fairly quickly.

How long is that usually?

Dr. Honeycutt: A year or two. So some of the worst ones are we’ve had a couple of patients about every six to nine months had to have their batteries changed.

And that’s a surgery as well?

Dr. Honeycutt: That’s a surgery as well to replace the batteries. Now the good news is it’s a pretty simple surgery. They go to sleep and just pop the old one out and put a new one in, but it’s still surgery.

Are there any kids that this doesn’t work for?

Dr. Honeycutt: We’ve been fortunate that so far in our series of almost 100 patients, somewhere close to 90 have worked. We had one family that we’ve taken it out because it just didn’t really work for them. Some work better than others and some of them you worry; we’ve had a couple of families that look at me and say is this really working, do you really think it’s having an effect and their adamant that it doesn’t – as they can see a change. We sometimes have a hard time seeing that but the families are adamant so we – – we replace the batteries and they keep going. So we’ve had a very low incidence or rate of you know of it really not working at all and we take it out.

Is there an age you have to be to get an implant?

Dr. Honeycutt: At this institution yes. As part of our research IRB, protocol they have to be at least seven years of age.

Will you walk me through the surgery like where you put the electrodes and also is it worrisome to put it in a kid?

Dr. Honeycutt: The way were doing surgery now with the ClearPoint system is the kids come in the operating room, they go to sleep just like any other kid going to sleep with general anesthesia. Once they’re asleep, we fixate their heads so it won’t move. We want it to be absolutely still throughout their entire operation. We then get ready for the surgery, prep their hair, do all our things we normally do and then we put these little grids on top of their hair. I don’t shave hair, by the way, we want to save hair. We put these little grids on and then we take our first MRI scan and that first MRI scan is just helping us determine where the best spot to put the hole in the skull. Once we have that spot, then we plan exactly where we want to put the electrode, so we actually plan exactly where we want to go. We then make an incision where the grid tells us to go to. We drill a hole in the skull and then we implant this plastic, what we call a tower, on top of the skull and that holds all of our equipment for us to put the electrode in. Once it’s all done, we then go back in the scanner and we start doing scans and we take this little tracking device that actually tells where this will project to in the brain, where the electrode will go so it’s sort like trying to hit a target on a video game. It takes about 30 minutes to an hour doing all these scans and little adjustments; little turn here, little turn there, and once were very happy with where we are we then slide a little stylet down to prove we’re at the correct spot, do a scan make sure we’re at the correct spot, and then we just slide the electrode down that spot and then lock it in place. Then we sort of tuck the electrodes under the scalp and then we close up. We come back a week later and then we put the extension wires and the generator in at the second operation then they’ll all be hooked up now.

And they’re all internal?

Dr. Honeycutt: All internal.

Because the brain is always moving and growing could these wires move to a place that they shouldn’t move to?

Dr. Honeycutt: One of our concerns we’ve had with doing kids is there’s a growing brain, there’s a growing skull. We’ve been looking into that and we’re just now having enough patients for a long enough time to be able to start commenting on that. So far, the electrode parts, we’ve not really had an issue with. And to be honest, by the time your age 7 you have a lot of your skull growth already, so you’re not going to get a whole lot more: somewhere between 80 and 90 percent of your skull growth is by age 7. So not a lot is going to change there. But one of the things we do worry about is the growth and is that stretching on the wire and scarring and breaking. And we do have a little higher rate of having problems with that compared to some adult series. The problem is I don’t know if that’s from dystonia or is that from having a pediatric population. So were trying to actively look into that right now and comparing to see if those rates are any different. But they may very well be. And we have seen some complications rates be higher in kids than we see in adults. I think it was a higher infection rate, there was a higher complication rate of strokes, and other things that we see on younger kids than we do in older patients.

Any reason why that is?

Dr. Honeycutt: We don’t know exactly why. But other centers that have been doing kids have noticed the same pattern also.

FOR MORE INFORMATION, PLEASE CONTACT:

Kristin Peaks
Cook Children’s Medical Center
Kristin.peaks@cookchildrens.org