Dystonia Association of Kentucky

Deep Brain Stimulation for Dystonia - An Overview for Patients

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, it is usually preferred over lesioning because it is reversible and adjustable; and does not permanently destroy any part of the brain.  Thus, pallidal DBS is the preferred surgery for dystonia at this time.

As of  2005, only about 150 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 bout 7 years.  Thus it cannot be considered a standard therapy until more procedures are done and the results of thm published.  However, because the initial reports of effectiveness have been very encouraging for some forms of dystonia, the United States Food and Drug Administration (FDA) recently granted a "Humanitarian Device Exemption" for the Medtronic DBS device to be used in the treatment of dystonia.  This indicates that the FDA recognizes the potential value of this therapy.

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 understand the nture and complexity of DBS therapy as well as the fact that the therapy is too new to gurantee successful treatment in any individual case.

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.

Since DBS for dystonia a relatively new therapy, insurers may deny coverage.  While there have been several insurers initially deny coverage, it has been found that all eventually agreed to cover the costs after appealing the decision and supplying medical literature that documented the results of the procedure.  Insurance approval or denial will be determined prior to the procedure.  Eventual approval is likely but not guaranteed.

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 sterotaxis, a method useful for approaching deep brain targets through a small incision and small skull opening.  With sterotaxis, 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 surgeion records brain cell activity, and checks the neurological response to electrical stimulation, in order to confirm the correct location before the surgery is completed.  The neurological exam of the patient including strength, vision, and speech, are monitored frequently during the operation to make sure there ar no new problems.  For a single brain electrode, 2-3 hours of awake surgery is required.  While pain can be eliminated, the discomfort of having to remain awake during the 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 sidef of the brain.  The two implants can be performed at the same time, or as two separate surgical procedures spaced several months apart if the patient is concerned about having a longer procedure.

For children who are less able to tolerate awake surgery, the procedure can be performed under general anesthesia.

The most serious potential risk of the surgical procedure is bleeding in the brain, producing a stroke.  This risk varis 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.

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 the inherited forms of dystonia appear to get very significant benefit.  For patients whith dystonia due to stroke or head trauma, the benefit may be only mild.  Many forms of adult onset cervical dystonia can benefit, although it is difficult to predict in advance the degree of benefit tht will be obtained.

Complete shaving of the head is not necessary for surgery.  However, a significant patch of hir on top of the had and behind the ear are shaved immediately before surgery when the patient is sedated.  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 one week after surgery.

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 then 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 genertor in the chest is closed with particular attention to minmize scar formation; this incision would be visible with the shirt off, or in a swimsuit, or in a low-cut evening gown.  In this 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.

DBS PATIENT RESOURCES ON THE INTERNET

For more information on Deep Brain Stimulation (DBS) surgery, visit Medtronic's web site at http://www.newhopefordystonia.com.  Medtronic is the manufacturer of the Activa brain pacemaker device used in DBS. 

An additional site sponsored by Medtronic is http://www.medtronic.com/newsroom/media_kits_Dystonia.html.

top