Neurosurgery : Philip A. Starr MD, PhD
Neurology: William Marks Jr. MD
Clinical Nurse Specialist: Heidi Clay RN
Clinic Coordinator: Diane Hollander
 
History of surgery for dystonia
What type of brain surgery is best for dystonia?
Is DBS for dystonia a standard, widely accepted therapy?
Who should consider having surgery for dystonia?
Will insurance companies pay for DBS for dystonia?
How is the surgery performed?
What are the risks of surgery?
What are the benefits of surgery?
What are the cosmetic considerations with DBS surgery?
How experienced is UCSF with deep brain stimulation?
What tests are needed prior to surgery?
What type of follow-up is needed after surgery? Who will program the DBS unit?
How long does it take before the full benefit of DBS is apparent?
 
History of surgery for dystonia
 
Brain operations to treat various forms of dystonia were first performed 40-50 years ago. The operations involved a precisely controlled lesioning (destruction) of deep structures in the brain involved in movement control. Two different deep structures, called the thalamus and the globus pallidus, were operated upon. Lesioning was performed by freezing or coagulation. Surgical techniques were much less advanced in that era than they are today, so the results were not consistent and complications were frequent.
 
In the last 5 years there has been a resurgence of interest in the surgical treatment of dystonia. There are several reasons for this:

1. Techniques for operating on deep brain structures have become much more precise and safe.
2. In addition to the older technique of brain lesioning, there is a new technique, deep brain stimulation (DBS), which involves placing a stimulation electrode rather than performing a brain lesion. DBS can alter the function of abnormal brain tissue in a way that improves movement, but it is reversible if there is an unwanted effect, and it can be adjusted during a routine office visit to optimize the degree of benefit. Thus it is somewhat safer than lesioning.
3. Patients with other, more common movement disorders are increasingly undergoing surgical treatment. These other movement disorders include tremor and Parkinson's disease. Success with these movement disorders has stimulated greater interest in surgery for more rare movement disorders such as dystonia.
4. Since 1995, a small number of publications in neurology and neurosurgery journals have shown that pallidal surgery for several forms of dystonia, using modern techniques, can be effective

What type of brain surgery is best for dystonia?
 
While this field is rapidly evolving, evidence is starting to accumulate that the best brain region for surgery for dystonia is the globus pallidus. This is a peanut-sized structure deep in the brain whose electrical activity is abnormal in dystonia.
 
While the older lesioning technique and the newer DBS technique can both be effective, we usually prefer DBS over lesioning because it is reversible and adjustable, and does not permanently destroy any part of the brain. Thus, pallidal DBS is our preferred surgery for dystonia at this time.
 
Is DBS for dystonia a standard, widely accepted therapy?
 
As of 2002, only about 50 cases of pallidal DBS for dystonia have been described in the world medical literature, and the longest time any patient has had this therapy is about 5 years. Thus it cannot be considered a standard therapy until more procedures are done and the results of them published.
 
Who should consider having surgery for dystonia?
 
Patients should consider deep brain stimulation for dystonia if they meet the following criteria:

1. The patient has been evaluated and treated by a qualified movement disorders neurologist who has clearly diagnosed the type of dystonia, and excluded other neurological problems.
2. The dystonia adversely affects quality of life by interfering significantly with normal activities or causing social isolation.
3. The patient's neurologist has attempted treatment with a variety of medications, which should at least include sinemet and anticholingergic medications such as trihexyphenydil (Artane). Baclofen and muscle relaxants such as clonazepam are also often tried before considering surgery.
4. The dystonia affects too large a body area to be treated effectively with injections of botulinum toxin (botox); or attempts at injection with botox have been tried and failed.
5. The patient clearly understands the nature and complexity of DBS therapy as well as the fact that the therapy is too new to guarantee successful treatment in any individual case.
6. The patient is willing to undergo fairly lengthy (3-4 hours) awake brain surgery.

In addition to the above considerations, DBS for dystonia appears to be more effective for certain forms of dystonia than others. Young persons with genetic forms of dystonia, especially those with the DYT-1 mutation, often have an excellent response to surgery.
 
Will insurance companies pay for DBS for dystonia?
 
Since DBS for dystonia is not a standard therapy, insurers may deny coverage at their own discretion. While we have had several insurers initially deny coverage, we have found that all eventually agreed to cover after appealing the decision and supplying medical literature that evaluated the procedure. Insurance approval or denial will be determined prior to the procedure. In our experience, eventual approval is likely but not guaranteed.
 
How is the surgery performed?
 
The surgery is performed through a small skull opening, with the patient awake, using only local anesthetic. Light intravenous sedation is used at the beginning and end. Surgery is guided by stereotaxis, a method useful for approaching deep brain targets through a small incision and small skull opening. With stereotaxis, a rigid frame is attached to the patient's head just before surgery, and a brain imaging study (usually an MRI) is obtained with the frame in place. The images of the brain and frame are used to calculate the position of the desired brain target and guide instruments to that target with minimal trauma to normal brain. To maximize the precision of the surgery, most surgeons use the electrical activity of the brain to guide the procedure. The surgeon records brain cell activity, or to check the neurological response to electrical stimulation, in order to confirm the correct location before the surgery is completed. The neurological status of the patient (such as strength, vision, and improvement of motor function) is monitored frequently during the operation. For a single brain electrode, 3-4 hours of awake surgery is required. While pain can be eliminated, the discomfort of having an awake operation with the head immobilized may be significant for some patients.
 
Patients with dystonia on both sides of the body will usually require electrodes to be placed on both sides of the brain. We normally do the two implants as two separate surgical procedures spaced 3-6 months apart.
 
What are the risks of surgery?
 
The most serious potential risk of the surgical procedure is bleeding in the brain, producing a stroke. This risk varies from patient to patient, depending on other medical factors, but generally ranges from 1-3%. If stroke occurs, it usually occurs during or within a few hours of surgery. Another risk is infection, especially of the deep brain stimulating hardware, which occurs in about 4-5% of patients. If an infection occurs, it is usually not life threatening, but may require immediate removal of the entire DBS system.
 
What are the benefits of surgery?
 
DBS surgery does not cure dystonia in any case. When the stimulator is turned off or if it malfunctions, the symptoms return. DBS can decrease the abnormal movements and postures of dystonia but usually does not totally eliminate them. The degree of benefit appears to vary with both the type of dystonia and the duration of the symptoms. Adolescents and young adults with inherited forms of dystonia appear to get very significant benefit. For patients with dystonia due to stroke or head trauma, the benefit may be only mild. Adults who have had dystonia for many years probably have less improvement than those with more recent onset of symptoms.
 
What are the cosmetic considerations with DBS surgery?
 
Complete shaving of the head is not necessary for surgery. However, a significant patch of hair from on top of the head to behind an ear is shaved immediately before surgery when the patient is sedated. This results in a hairstyle that would be considered strange outside of San Francisco. Many patients elect to get a short haircut after surgery (must be at least 2 weeks afterwards) so that the hair grows in evenly. When hair grows back, incisions are not visible.
 
There is often puffiness around the eyes for a few days after surgery, but this goes away rapidly.
 
There are generally 3 incisions made for DBS surgery: a 5 cm (2 inch) incision on top of the head, a 2.5 cm (1 inch) incision behind the ear, and a 6 cm (2.5 inches) incision in the chest just under the clavicle. For adult patients with receding hairlines, a slight scar from an incision will be visible on top of the head, but is not especially prominent. The cap used to anchor the DBS electrode (under the scalp) forms a slight bump, which again may be visible but not prominent in the case of a receding hairline.
 
All parts of the device are internal (under the skin), so there are no wires sticking out. In a thin person, the connecting wire running down the neck may be visible as a slight bulge when the head is turned all the way to the opposite side. The incision for the pulse generator in the chest is closed with particular attention to minimize scar formation; this incision would be visible with the shirt off, or in a swimsuit, or in a low-cut evening gown. In thin persons, the pulse generator itself forms a bulge under the skin in the pectoral area that may be apparent if the area is uncovered, but is not visible through clothing.
 
How experienced is UCSF with deep brain stimulation?
 
At UCSF we have performed over 300 DBS surgeries for a variety of movement disorders since 1998. As of 2002, we have performed 22 pallidal DBS surgeries specifically for dystonia, as well as 60 pallidal DBS surgeries for another movement disorder, Parkinson's disease. We have a research grant funded by the National Institutes of Health to study surgery for dystonia.
 
What tests are needed prior to surgery?
 
All patients must have had a brain MRI at some time since the onset of dystonia. All patients must have a detailed videotaped neurological evaluation by Dr. William Marks, lasting several hours, to document the severity of dystonia.
 
What type of follow-up is needed after surgery? Who will program the DBS unit?
 
Patients normally leave the hospital two days after surgery. We ask patients to return to our clinic 1 week later for suture removal and check of the incisions by our DBS nursing specialist, and approximately 4 weeks later to see the surgeon and neurologist in the Movement Disorders Surgery Clinic. The initial programming is done at UCSF between 1 day and 30 days after surgery. Some patients have temporary disorientation for a few days after surgery due to temporary brain swelling, and if this occurs programming is deferred until the mental state completely returns to baseline. For subsequent programming needs after the initial stimulator activation, the patient is encouraged to continue in our Movement Disorders Clinic. For patients who live at a distance from the Bay Area and have a neurologist with a DBS programmer, we are happy to advise other neurologists regarding optimal programming strategies for dystonia.
 
How long does it take before the full benefit of DBS is apparent?
 
For reasons that are not fully understood, it takes approximately 3-12 months for the full benefit of any particular programming setting to reach its maximum level.