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Movement Disorders
The University of Washington has a long-standing interest in the surgical treatment of movement disorders, including pallidotomy, thalamotomy, DBS and radiosurgery. Patients are evaluated by a multidisciplinary team consisting of neurologists and neurosurgeons to determine if a surgical procedure is appropriate for the treatment of their movement disorder. Drs. Robert Goodkin (neurosurgery), and Ali Samii (neurology) head this effort. If the patient appears to be a suitable candidate, further preoperative testing is obtained and surgery is scheduled. Surgery is performed using both anatomic localization and by recording the activity of the neurons in this region. This enables our team to identify the specific neuronal regions that are abnormal, based on neuronal recordings, as opposed to relying solely on anatomic parameters. Dr. Goodkin specializes in the placement of deep brain stimulators (DBS), while Dr. Ojemann specializes in pallidotomies and thalamotomies. Follow-up occurs at six months after surgery and includes functional testing as well as MR imaging. If the patient had a successful response and symptoms on the opposite side of the body warrant a second procedure, the patient will then be scheduled for this.
For more information on movement disorders and their treatments, please read the following primer:
Movement disorders refer to abnormal movements of the arms and legs that cause difficulty with walking, daily activities, and tremor. A variety of conditions cause these problems, including Parkinson’s disease, multiple sclerosis and essential tremor. While there is no known cure for these conditions, the movement disorders that they cause can be treated with medication and surgical procedures. Four different surgical procedures are available for patients who suffer from movement disorders; each one has distinct advantages and disadvantages and may not be suitable for all patients.
Pallidotomy
A pallidotomy is a surgical procedure that was developed in the 1950's
for the treatment of the symptoms of Parkinson's disease. With the introduction
of medical therapy for Parkinson's disease in the 1960's, this surgical
procedure became less utilized. Recently, with improvements in technology,
interest in pallidotomy has resumed.
Pallidotomy is performed using stereotactic procedures which enable the surgeon to identify the region of the brain to be lesioned using a CT or MRI scan. The procedure consists of producing a small lesion in a very specific region of the brain called the globus pallidus, which interrupts nerve signal transmission to other brain regions. This lesion results in the reduction of rigidity and abnormal movements that are symptoms of Parkinson's disease, and in some cases, reduces tremor. Thus, this procedure is designed to treat symptoms but not cure Parkinson's disease. Most patients need to continue medications, though the medications may be reduced or be more effective for longer periods of time. The patient's primary care physician is critical to this program, since that physician will be involved in adjustment of medications and will oversee the patient's routine health care needs.
Certain conditions may make pallidotomy inappropriate for certain patients. For example, patients with cognitive difficulties and memory problems, severe joint deformities or underlying medical conditions such as severe hypertension, multiple strokes or brain tumors may be at high risk for this procedure. Age itself is not an exclusionary factor, but patients over age 75 may have increased risk of complications (stroke/death) or may be less likely to respond to the procedure.
Thalamotomy
Thalamotomy is a procedure that is used for treatment of tremor caused
by a number of disorders including Parkinson's disease, multiple sclerosis
and essential tremor. Like pallidotomy, this procedure is done through
stereotactic localization, and a small surgical lesion is created in the
thalamus, a structure deep within the brain.
Like pallidotomy, certain conditions may preclude patients from benefiting from this procedure. Thalamotomy does not help some of the symptoms of Parkinson's disease, such as slowed movements.
Deep Brain Stimulator (DBS)
In 1997, the Food and Drug Administration approved the use of deep brain
stimulation for the treatment of essential tremor and Parkinson's tremor.
This technique can replace thalamotomy or be used in addition to thalamotomy.
DBS uses stereotactic techniques similar to those described for pallidotomy,
but instead of creating a lesion in the brain, an electrode is placed
into a specific structure of the brain. When activated, this electrode
causes the tremor to diminish. The battery pack and the generator are
located under the skin of the chest. The DBS is programmed to send tiny
electrical impulses to the brain to control the tremor. Patients can turn
the DBS on or off using a small magnet.
Radiosurgery
For patients for whom surgery is too risky, radiosurgery may be a viable
alternative to an open operation. Radiosurgery is a technique in which
a single high dose of radiation is targeted to a very specific region
of the brain, creating a lesion. As with other procedures described above,
stereotactic techniques are used to identify the target. There are certain
advantages and disadvantages to this technique, which must be addressed
by the patient’s neurosurgeon.
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