Deep Brain Stimulation for Dystonia
Deep brain stimulation is a surgical intervention used to treat movement disorders such as dystonia when the regimen of existing medications and the various rehabilitation strategies become less effective in managing symptoms. It is currently approved for the treatment of dystonia through a "humanitarian device exemption" from the Food and Drug Administration. This surgical procedure received approval from the Food and Drug Administration to treat tremor in Parkinson’s disease in July 1997 and for advanced motor symptoms of Parkinson’s disease in January 2002.
This video shows a patient with primary dystonia before and after his surgery.
Deep brain stimulation (DBS) appears to be most effective in those with primary or hereditary dystonic conditions such as torticollis or cervical dystonia and dystonia musculorum deformans (DYT1 dystonia). It can also help tardive dyskinesia, which is a movement disorder caused by certain medications.
The level of benefit from DBS is not as significant in secondary dystonia that is associated with cerebral palsy and/or other types of damage to the brain. More research is needed to determine how to best treat these conditions.
DBS for the treatment of dystonia involves administering a controlled electrical current into the globus pallidus (GPi), the malfunctioning portion of the brain.
Unfortunately, the stimulator does not cure or halt the disease and residual symptoms can increase with disease progression. DBS does continue to provide the same percentage of symptom reduction/overture.
When is it time to consider DBS surgery?
- Genetic dystonia
- For people with genetic dystonia such as DYT1 dystonia, referral should be considered as soon as the movement disorder becomes problematic.
- Children with persistent dystonia will develop permanent skeletal deformities as a result of the effect of the dystonia on their bone growth. DBS can prevent this but cannot reverse the skeletal abnormalities. Therefore, it is important that they have surgery before these problems develop.
- Adult onset torticollis
- Patients should consider surgery if they do not respond to or cannot tolerate medications and botulinum toxin injections.
- Tardive dyskinesia
- Patients should consider surgery if they are not responsive to medications.
Who may be a candidate for DBS surgery?
People with various forms of dystonia including the following:
- Genetic dystonia – This group of conditions can be severely disabling and can lead to permanent bone deformity. DBS should be considered before permanent damage occurs. Patients with these disorders typically have an excellent response to DBS therapy.
- Primary or idiopathic dystonia – There is no known cause for this group of conditions. The MRI scans in people with these dystonias appear to be normal and there does not appear to be any hereditary factors. These patients typically respond well to DBS surgery similar to those with a genetic form of dystonia.
- Cervical dystonia (torticollis) – This form of dystonia can be treated with DBS therapy if the symptoms become painful and disruptive despite best medical therapy including botulinum toxin injections.
- Tardive dyskinesia- This condition, caused by certain medications, involves abnormal movement of the mouth and eyes. DBS surgery can be an effective treatment in reducing these symptoms.
- Cerebral palsy (CP) – There is typically a poor response to DBS surgery with only small improvement (10-20%) in the abnormal movements. In general, this does not warrant the risk of the procedure.
Who may not be a candidate for DBS surgery?
For people who meet one of the following criteria, DBS surgery is not a good option:
- Are too unhealthy to undergo surgery
- Cerebral palsy (CP) - There is typically a poor response to DBS surgery with only small improvement (10-20%) in the abnormal movements. In general, this does not warrant the risk of the procedure.
For people who meet one of one of the following criteria, DBS surgery may not be advisable, and should be considered carefully:
- Cardiac pacemakers and defibrillators
- By implanting the DBS generator more than 8 inches away from the cardiac device, most problems can be avoided. If the patient's life is dependent on uninterrupted cardiac device function, DBS is generally contraindicated.
- Regular MRI imaging
- Patients who have an implanted DBS system cannot have an MRI scan of any part of the body as it could lead to brain tissue damage.
- Head MRIs can be performed using specific scanning equipment under the supervision of an experienced DBS team.
- Anti-coagulant therapy such as Coumadin or Aggrenox
- A specific evaluation is needed to determine whether or not these medications can be safely withheld for approximately three weeks.
What outcomes can be expected from DBS for people with dystonia?
- For people with various forms of dystonia, an improvement in involuntary movements is experienced initially with postural improvements typically taking longer.
- The symptoms of dystonia may respond more slowly to stimulation than in other movement disorders and it can take up to 3-12 months for individuals to experience maximum benefit. The long term benefits of dystonia DBS appear to be longer lasting than for the other disorders, but this depends on whether the dystonia was progressing at the time of surgery.
- Common improvements for people with dystonia include:
- Genetic dystonia - 80-99% improvement of symptoms is common
- Cervical dystonia (torticollis) - 40-60% improvement is often seen but not all patients respond. Pain and the neck movement and posture sometimes respond separately such that a patient can have improvement in one but not the other.
- Tardive dyskinesia - 80% improvement is common
- Cerebral palsy - typically see 0-20% response
What are the potential risks of DBS surgery?
- 1-3% risk of intracranial hemorrhage which can lead to loss of speech, paralysis, coma, or death.
- 5% risk of infection which usually requires removal of the DBS system.
- DBS will offer little or no benefit. The chance of this is dependent on the patient's diagnosis or can be due to suboptimal lead placement, requiring revision.
- Risks of anesthesia which are dependent on the patient's overall medical history.
What is the pre-operative DBS evaluation process?
Individuals interested in learning more about DBS surgery should contact the DBS team at (804) 364-6519 to set up an informational appointment. At this appointment patients are given a packet of educational materials. Clinical notes are obtained from the referring neurologist and primary care provider. If a patient has not seen a neurologist, an appointment with a movement disorders specialist will be scheduled to confirm that the patient is a good candidate for surgery.
Deep Brain Stimulation Resources
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Please call (804) 360-4NOW (4669) to schedule an appointment.