Deep brain stimulation





Definition

Deep brain stimulation (DBS) delivers a constant low electrical stimulation to a small region of the brain, through implanted electrodes connected to an implanted battery. It is used to partially restore normal movements in Parkinson's disease, essential tremor, and dystonia.


Purpose

Parkinson's disease is due to degeneration of a group of cells called the substantia nigra. These cells interact with other brain regions to help control movement. The normal signals from the substantia nigra inhibit these other regions, and so when it degenerates, these regions become overactive. The electrical signals from the DBS electrodes mimic the inhibitory function of the substantia nigra, helping to restore more normal movements.

The substantia nigra normally releases the chemical dopamine, which exerts its inhibitory action on the globus pallidus interna (GPi) and the subthalamic nucleus (STN). For Parkinson's disease, deep brain stimulation is performed on these two centers. The target for DBS in dystonia is the GPi as well. Treatment of essential tremor usually targets the thalamus.

Each of these brain regions has two halves, which control movement on the opposite side of the body: right controls left, and left controls right. Unilateral DBS may be used if the symptoms are much more severe on one side. Bilateral DBS is used to treat symptoms on both sides.


Demographics

Parkinson's disease affects approximately one million Americans. The peak incidence is approximately age 62, but young-onset PD can occur as early as age 40. Because young-onset patients live with their disease for so many more years, they are more likely to become candidates for surgery than older-onset patients. In addition, younger patients tend to do better and have fewer adverse effects of surgery. Approximately 5% of older PD patients receive one form or another of PD surgery. Many more develop the symptoms for which surgery may be effective, but either develop them at an advanced age, making surgery inadvisable, or decide the risks of surgery are not worth the potential benefit, or do not choose surgery for some other reason.

Essential tremor is more common than Parkinson's disease, but rarely becomes severe enough to require surgery. Dystonia is a very rare condition, and the number of patients who have received DBS as of 2003 is under 100.


Description

Deep brain stimulation relies on implanting a long thin electrode deep into the brain, through a hole in the top of the skull. In order to precisely locate the target area and to ensure the probe is precisely placed in the target, a "stereotactic frame" is used. This device is a rigid frame attached to the patient's head, providing an immobile three-dimensional coordinate system, which can be used to precisely track the location of the GPi or STN and the movement of the electrode.

For unilateral DBS, a single "burr hole" is made in the top of the skull. Bilateral DBS requires two holes. A strong topical anesthetic is used to numb the skin while this hole is drilled. Since there are no pain receptors in the brain, there is no need for deeper anesthetic. In addition, the patient must remain awake in order to report any sensory changes during the surgery. The electrode is placed very close to several important brain structures. Sensory changes during electrode placement may indicate the electrode is too close to one or more of these regions.

Once the burr hole is made, the surgeon inserts the electrode. Small electric currents from the electrode are used to more precisely locate the target. This is harmless, but may cause twitching, light flashes, or other sensations. A contrast dye may also be injected into the spinal fluid, which allows the surgeon to visualize the brain's structure using one or more imaging techniques. The patient will be asked to make various movements to assist in determining the location of the electrode.

The electrode is connected by a wire to an implanted pulse generator. This wire is placed under the scalp and skin. A small incision is made in the area of the collarbone, and the pulse generator is placed there. This portion of the procedure is performed under general anesthesia.


Diagnosis/Preparation

DBS for Parkinson's disease is considered as an option in a patient who is still responsive to levodopa (used to treat symptoms) but has developed motor complications. These include the rapid loss of benefit from a single dose (wearing off), unpredictable fluctuations in benefit (on-off), and uncontrolled abnormal movements (dyskinesias). Essential tremor patients who are candidates for surgery are those whose tremor is unsatisfactorily controlled by medications and whose tremor significantly impairs activities of daily living. Similar criteria apply for dystonia patients.

The patient who is a candidate for DBS discusses all the surgical options with his neurologist before deciding on deep brain stimulation. A full understanding of the risks and potential benefits must be understood before consenting to the surgery.

The patient will undergo a variety of medical tests, and one or more types of neuroimaging procedures, including MRI, CT scanning, angiography (imaging the brain's blood vessels) and ventriculography (imaging the brain's ventricles). On the day of the surgery, the stereotactic frame is fixed to the patient's head. A local anesthetic is used at the four sites where the frame's pins contact the head; there may nonetheless be some initial discomfort. A final MRI is done with the frame in place, to set the coordinates of the targeted area of the brain in relation to the frame.

The patient will receive a mild sedative to ease the anxiety of the procedure. Once the electrodes are positioned, the patient receives general anesthetic to implant the pulse generator.


Aftercare

The procedure is lengthy, and the patient will require a short hospital stay afterward to recover from the surgery. Following the procedure itself, the patient meets several times with the neurologist to adjust the stimulation. The pulse generator is programmable, and can be fine-tuned to the patient's particular needs. This can provide a higher degree of symptom relief than lesioning surgeries, but requires repeated visits to the neurologist. Pulse generator batteries must be replaced every three to five years. This is done with a small incision as an outpatient procedure. Since the generator is in the chest area, no additional brain surgery is required.

The patient's medications are adjusted after surgery, with a reduction in levodopa likely in most patients who receive DBS of the subthalamic nucleus.


Risks

Deep brain stimulation entails several risks. There are acute surgical risks, including hemorrhage and infection, and the risks of general anesthesia. The electrodes can be placed too close to other brain regions, which can lead to visual defects, speech problems, and other complications. These may be partially avoided by adjusting the stimulation settings after the procedure. Because a device is left implanted under the skin, there is the risk of breakage or malfunction, which requires surgical removal.

A patient with implanted electrodes must not receive diathermy therapy. Diathermy is the passage of radiowaves through the tissue to heat it, and is used as a physical therapy for muscle pain and other applications. Diathermy poses a risk of death in a patient with DBS electrodes.

Patients who are cognitively impaired may become more so after surgery, and cognitive impairment usually prevents a patient from undergoing surgery.


Normal results

Deep brain stimulation improves the movement disorder symptoms of Parkinson's disease by 25–75%, depending on the care of the placement and the ability to find the optimum settings. These improvements are seen most while off levodopa; DBS does little to improve the best response to levodopa treatment. Levodopa dose will likely be reduced, leading to a significant reduction in dyskinesias.


Morbidity and mortality rates

The rate of complications depends highly on the skill and experience of the surgical team performing the procedure. Rates from one of the most experienced teams, in a study of over 200 patients, were as follows.

Post-operative complications:

  • asymptomatic intracranial bleed (10% of procedures)
  • symptomatic intracranial bleed (2%)
  • seizures (3%)
  • headache (25%)
  • infection (6%)

Device-related complications:

  • lead replacements (9%)
  • lead repositionings (8%)
  • extension wire replacements (6%)
  • implantable pulse generator replacements (17%), approximately half of which were due to malfunction

The risk of death is less than 1%.


Alternatives

Patients who are candidates for deep brain stimulation have usually been judged to require surgery for effective treatment of their symptoms. Other surgical alternatives for Parkinson's disease include pallidotomy and thalamotomy, which destroy brain tissue to achieve the same effect as the stimulation. Pallidotomy is rarely performed for Parkinson's disease, unless tremor is the only debilitating symptom. It is common in essential tremor. DBS for dystonia is the only really promising neurosurgical treatment for this condition. Some peripheral surgeries may be appropriate for selected patients.

Resources

BOOKS

Jahanshahi, M., and C. D. Marsden. Parkinson's Disease: A Self-Help Guide. New York: Demos Medical Press, 2000.

ORGANIZATIONS

National Parkinson's Disease Foundation. Bob Hope Parkinson Research Center, 1501 N.W. 9th Avenue, Bob Hope Road, Miami, FL 33136-1494. (305) 547-6666. (800) 327-4545. Fax: (305) 243-4403. http://www.parkinson.org .

WE MOVE, Worldwide Education and Awareness for Movement Disorders. 204 West 84th Street, New York, NY 10024. (800) 437-MOV2, Fax: (212) 875-8389. http://www.wemove.org .


Richard Robinson

WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?


Deep brain stimulation is performed by a neurosurgeon in a hospital.

QUESTIONS TO ASK THE DOCTOR


  • How many electrode implantations has the neurosurgeon performed?
  • What is his own rate of serious complications?
  • Would pallidotomy be appropriate for me?
  • How will my medications change after the operation?


User Contributions:

Maurice LeBlanc
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Mar 28, 2006 @ 8:08 am
My wife has been diagnosed with Spasmodic Respiratory Dystonia and Blepharospasms. She has problems speaking and breathing because the area around her vocal chords is continuously spasming. Her eyes need botox to relax the muscles so they will stay open.
Medications don't seem to help much. Would she be a candidate for DBS?
We are looking for anything that will improve her condition.
Jane
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Jun 1, 2007 @ 8:08 am
You know I do think it would be help your wife a great deal.
Janie
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Jun 1, 2007 @ 8:08 am
I seen that I had made some errors on my first post. So let me start over. Yes, I think this surgery would help your wife a great deal. Why not talk to a Movement Doctor to get the ball rolling.I really hope that all goes well for her to!
janice
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Jun 29, 2008 @ 11:11 am
HELLO I JUST WENT IN LAST WEEK FOR DBS SURGERY,WELL TO MAKE THIS AS SHORT AS POSSIBNLE MY FAMILY AND ALL CAME FROM OUT OF TOWN FOR THIS.WELL ANYWAY I WAS IN SURGERY FOR HOURS OR EIGHT.BUT THEN THEY SAID THAT THE MEDTONIC HAD A DEFECT OR SOMETHING LIKE THAT,SO OF COURSE THE SURGERY DIDN,T WORK..WELL NOW I AM GOING TO TRY AGAIN ON JULY 14.NOW THEY SAID THIS TIME IT WILL BE SOMETHING ON MY HEAD.(I HAVE ALREADY HAD 4 SCREWS PUT IN MY HEAD THE DAY BEFORE MY SURGERY LAST WEEK,AND THEY TOOK THEM OUT ALREADY.AND I ALSO HAVE AROUND 30 STAPLES IN MY HEAD NOW.I AM JUST A LITTLE SCAREED TO GO THREW ALL THIS AGAIN.BUT I REALLY WANT THIS TO WORK...THANKS PLEASE LET ME KNOW WHAT YOU THINK
Jane
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Feb 21, 2009 @ 10:10 am
D.B.S.
So, exactly how can someone get one (or two) of these things removed if they had no medical need for it in the first place, and when (according to our laws in Australia) Radiologists don't have to report what they see in Film so they are saying anything so their medical chums don't get into strife.
So, exactly hoe can one get a device like this removed if it's defective or old and is breaking down causing a massive amount of electrical stimulation around the scalp and abdomen and chest?
Exactly how?
Jane, South Australia.
www.janettegailhall.webs.com
Dianne
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Aug 20, 2009 @ 3:03 am
I have tremors,cfs and fibromyalgia. I take narcotics,Cymbalta for pain and as a antidepressant and I take clonzapem for the tremors. Along with fiah oil pills, blood pressure medicine and I am taking so much medicines until I don't think Icould swallow another pill. I stll hurt. I'm fatigued all the time and the pain management doctor is doing what she can to maanage the pain. I am a 57 year old African America female. I just had gall bladder removal and interrstim therapy surgery and I can tell my overactive bladder is like knew and no loner stay nausea because my gallblader wasn't functioning properly. Would I be a good patient for dbs surgery?
Charles
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Sep 10, 2009 @ 9:09 am
Had DBS for essential tremor about 2 years ago. I really works good. About 2-3 months ago I began having severe headaches with disorentation. Anyone heard of this?
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Aug 29, 2010 @ 10:10 am
My name is Corey Alan Phillips, and I have spastic cerebral Palsy and I'm Confined to a wheelchair. My neurololest has tried everything to control the spasms like the baclofen pump.
Which had to be removed because the doctor did'nt make the pocket deep enough.And now I can't get the pump anymore. So do you think that deep brain stimulation would work for me.

Thank- you
Corey Alan Phillips
chitra
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Apr 25, 2011 @ 12:00 am
My mother has undergone deep brain surgery last year. however post surgery she has developed dyspnea. kindly advice what could be the cause and how to treat her. she takes asthalin off and on for relief but sometimes it becomes very severe. Thanks.
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Sep 6, 2011 @ 10:10 am
I have Early Onset PD (I'm 46) and I am no longer responding to non-Levodopa meds (Mirapex, etc). My Neuro has been wanting to wait until the last minute to switch to Levodopa because it (& others like it) tend to wear off quickly over time. Unfortunately, at my age, time is not a luxury.
He has suggested going to Nashville & trying to get into their DBS surgical program. I only hope that I am a candidate. Although, I am terrified! It has got to be better than waiting around to become like some of the people I see on YouTube :(
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Oct 13, 2011 @ 8:20 pm
I HAVE PARKINSONS DISEASE AND EVEN THOUGH MY TREMORS ARE SOMEWHAT A BOTHER THEY ARE NOT BAD.BUT I THINK THAT ONE OF THESE SURGERIES WOULD HELP ME,TO DELAY THE TREMORS FROM BECOMING ADVANCED.BUT WHAT CONCERNS ME IS THAT BY DOING ONE OF THESE IT WOULD SET ME BACK BECAUSE I KNOW THAT I CANNOT BE WHERE MAGNETS ARE BEING USED AND NOWADAYS THEY ARE EVERYWHERE.I WONT BE ABLE TO GO ANYWHERE AND THE IDEA IS TO HAVE A BETTER QUALITY OF LIFE .NOT BECOME A HERMIT .I KNOW THERE IS THREE TYPES OF SURGERY DEEP BRAIN STIMULATION,WHERE THE PATIENTS ARE PUT INTO A DEVICE TO HOLD THEIR HEADS STILL WHILE THE DOCTOR DRILLS A HOLE TO PUT ELECTRODES IN HEAD .THAT SCARES THE HELL OUT OF ME. THERE IS ANOTHER PROCEDURE NUCLEAR STIMULATION. WHICH IS ALSO WITH ELECTRODS. CAN ANYONE GIVE SOME INFO PLEASE. NEED IT TO DECIDE ALSO HOW LONG ARE YOU IN SURGERY THANK YOU
David Watkin
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Feb 16, 2012 @ 1:13 pm
Deep Brain Stimulation, I have been recommended for this surgery because of essential tremour and it effects my hand neck and speech and there is no further drug treatment. This is a good article. Dave
Fabi
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Mar 23, 2012 @ 10:10 am
Hello all,

Just to do two little observations: first, at the beginning of this article it is mentioned "...constant low electrical". Well that is actually not constant but voltage or current pulses. The neurons usually are not stimulated to constant signals.
The other observation is for Lilly who was scared of the magnets; the latest devices are very well protected against electromagnetic interference so don't worry :)
A.J.
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Nov 9, 2012 @ 4:16 pm
I am working with a college student who had DBS surgery five years ago for dystonia. He is requesting an exemption from our campus housing requirement for freshmen due to "high sensitivity to electromagnetic fields" as a result of the device. (He cites wiring in the walls in certain places, as well as being surrounded by the use of other students' devices as disturbing.) He also reports being unable to use headphones to listen to music for the same reason. The campus housing is in apartment-style units,in a building that was constructed in the late 1970s or 1980s. What is the likelihood the types of circuitry to which he is exposed in this setting would produce a magnitude of electromagnetic interference sufficient to cause frequent disturbance? Thanks very much in advance.

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