Surgical Management

Greetings from Dr. Rosenow

Joshua M. Rosenow Photo

Welcome to Northwestern University’s Parkinson’s Disease and Movement Disorders Center. Here, professionals from a wide range of disciplines work together to offer the most comprehensive care in the region to patients with movement disorders, such as Parkinson’s disease, tremor, and dystonia.

Patients have access here to not only the best current medical therapy, but also trials of cutting edge medications that offer hope to those for whom current regimens have proven inadequate. Dr. Tanya Simuni, Medical Director of the Parkinson's Disease and Movement Disorders Center, is the author of numerous publications on the treatment of movement disorders and is a recognized expert in the field.

Over the last several years, surgery has begun to play an increasingly prominent role in the management of movement disorders. Where surgeons used to create destructive lesions in the brain, Northwestern neurosurgeons now implant sophisticated stimulation devices to relieve disabling symptoms such as tremor, rigidity, slowness, and dyskinesia. At Northwestern, we are continuously investigating ways to improve upon current treatment. Northwestern was the first center in the Chicagoland region to use frameless technology to place deep brain stimulating electrodes without the use of the traditional confining stereotactic frame. This allows the patient’s head to remain unrestrained during the operation and shortens the procedure. Dr. Joshua M. Rosenow, Director of Stereotactic and Functional Neurosurgery, was part of the team that refined this procedure, and he participated in some of the first fully frameless deep brain stimulation procedures ever performed. His work has been presented internationally, and he is a frequent speaker at national meetings.

However, what truly sets Northwestern apart is the comprehensive care offered to patients with movement disorders. The Northwestern University movement disorders team understands that living with a movement disorder involves more than just medical and surgical needs. As a result, Northwestern provides an integrated program of clinical nursing, nutrition, physical and speech therapies, and social work. Diane Breslow, MSW, LCSW, our Center Coordinator, has over 3 decades of experience in the Chicago region working with patients with movement disorders. She has lectured extensively on the comprehensive approach to management of movement disorders and has authored several publications, including one book. Diane understands how illness and disability impact not only the patient, but also the entire family system. Having counseled movement disorder patients and their families in every type of setting and level of care, Diane has a unique knowledge of, and perspective on, all facets of PD. Through the PD 101 program of seminars, Diane gives patients and their families a thorough introduction to all aspects of thriving with the disease.

If you have any questions, or would like more information, please call 312-503-4397 or 312-695-2168 (Neurology) or 312-695-8143 (Neurosurgery), or e-mail DBS@northwestern.edu.

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Overview

Surgery was an important treatment option prior to the introduction of levodopa in the late 60's. Since then, surgery fell into oblivion only to be revised in the early 90's with the benefit of more advanced surgical and neuroimaging equipment. Surgery should be considered only for patients who fail medical management. The success of surgery to the greatest degree depends on appropriate selection of surgical candidates.

A newer neurosurgical procedure allows implantation of an electrode—deep brain stimulator (DBS)—into a specific area of the basal ganglia/thalamus that, when activated from a subcutaneously placed battery (similar to a pacemaker), produces a high frequency signal, causing functional lesioning without the creation of a permanent lesion.

Questions about Surgical Treatment of Movement Disorders

Which movement disorders can be treated surgically?

There are several movement disorders that may be successfully treated surgically when medical options have proven unsatisfactory. Essential (or benign familial) tremor is very well controlled with surgery. Other tremors, such as those due to multiple sclerosis (MS) and brain injury, may also respond to surgery, but the results are somewhat less satisfying and less consistent than those for essential tremor.

Many patients with advanced Parkinson's disease also respond well to surgery. However, patients with “Parkinson plus” syndromes, such as multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration, do not improve after surgery, even though these people may have many of the same clinical features as those with Parkinson's disease.

What is deep brain stimulation (DBS) surgery?

Deep brain stimulation surgery involves implanting 1 or more small electrodes in very specific regions deep in the brain to deliver continuous high frequency electrical impulses to the brain. These impulses alleviate the symptoms of severe movement disorders, even though it does not cure them. Each electrode has 4 contacts at the tip. Stimulation may be performed through any combination of 1 or more of these contacts. In addition, the strength of stimulation, length of each pulse, and the number of pulses per second may be adjusted to individualize the stimulation so that each patient achieves the best results possible. Each electrode is connected to an extension wire that runs under the skin behind the ear and down the neck to an implantable pulse generator (“pacemaker”) that is usually placed under the skin of the upper chest.

Who is a candidate for deep brain stimulation?

Patients with essential and other tremors are considered candidates for deep brain stimulation if their tremors are uncontrolled despite adequate trials of several medications, such as Inderal (propranolol) or Mysoline (primidone). A patient is also a candidate if he or she experiences medication side effects, such as slow heartbeat or sleepiness.

Patients with Parkinson's disease are candidates for surgery if they still achieve some benefit from their medication, but have significant side effects or other medication-related problems. These include freezing, rapid or unpredictable on/off fluctuations, dyskinesias (uncontrolled movements), sleepiness, nausea, and early wearing-off of the medication effects. As previously stated, patients need to have only Parkinson's disease and not one of the other syndromes that has Parkinson-like features along with other symptoms.

Patients with torticollis and dystonia are candidates for surgery if they still have significant disability even after adequate trials of antispasmodic medications such as baclofen as well as injections such as botulinum toxin (Botox) A and/or B.

Regardless of their reason for surgery, all patients must undergo an evaluation here at Northwestern prior to being deemed a surgical candidate. This includes:

  • Review of records from your current neurologist that document past treatment efforts, and/or an assessment by our team neurologist.
  • MRI of the brain within the last year, to make sure there are no other factors that could account for the symptoms, as well as to insure there are no anatomic hindrances to surgery.
  • Detailed neuropsychological evaluation to make sure there is no untreated anxiety or depression. These problems do not completely prevent a person from having surgery. They just need to be under treatment so that they do not interfere with the surgery or postoperative period. People with dementia, however, are not candidates.
  • Detailed medical evaluation to medically optimize patients before surgery. This may be done by your own family doctor.

How is deep brain stimulation performed?

Patients undergo a special MRI scan up to several weeks before the surgery. Patients with Parkinson's disease are admitted to the hospital the night before surgery and are taken off their Parkinson's medications starting at midnight. Patients with tremor come to the hospital the morning of surgery and do not take their tremor medication that morning.

In the morning, a special device called a stereotactic frame is attached to the skull using 4 pins. Local anesthesia is used to ensure that this part of the procedure does not hurt. Most people say it feels like a squeezing sensation on their head for about 15 minutes, and then they do not feel it anymore. A CAT (CT) scan is then performed with the frame on.

The CT and MRI pictures are loaded into a computer system in the operating room that allows the surgical team to merge the 2 pictures together. This enables the team to use the information from both scans to precisely target the correct location in the brain. The exact target is selected using a combination of direct visualization of the location on the MRI and CT scans and known formulas which locate the targets relative to known landmarks in the brain. The computer system also lets the team pick the entry point for the electrode on the skull as well as simulate the entire trajectory of the electrode. This makes sure that the electrode passes only through safe regions of the brain. The trajectory is adjusted until the optimal path is found. This serves to get us close to the target. We must then map the exact location in the brain to ensure the best results.

The patient lays on the operating table with the frame attached to the table itself for stability. After the surgical drapes are placed, intravenous medication is given to allow the patient to sleep while the skin incisions are made. A small hole (about the size of a nickel) is made in the skull according to the plan mapped out on the computer. Once this is done, a very thin microelectrode is inserted into the brain to map the exact best location for the permanent electrode. The patient is awakened at mapping begins. Each location in the brain has its characteristic patterns of nerve cell signals. The team listens to these to determine the exact location of the electrode. The patient becomes an integral part of the team at this point. The patient's arms and legs are moved to see if this affects the firing of the nerve cells. In addition, the patient is asked to speak, look around, and relate if he or she feels any tingling or pulling in the arms, legs, or face.

Once the correct location is determined, the mapping electrode is removed and the permanent electrode placed. This electrode is then turned on in the operating room to check the effects. The surgical team looks not only for good effects, but unwanted side effects as well. If a satisfactory balance is found (few bad effects and many good effects), the electrode is secured at that location and the incision closed while the patient sleeps again.

Patients with Parkinson's disease typically have one electrode placed on each side of the brain in an area called the subthalamic nucleus (STN). Patients with tremor have a single electrode placed in the thalamus on the side of the brain opposite their most severe or most disabling tremor. Patients with dystonia have electrodes placed in the globus pallidus side of the brain opposite their most severe symptoms. Some tremor and dystonia patients only require operations on 1 side of the brain, while some will require an electrode on each side for optimal relief.

After the electrodes are placed, the frame is removed and patients go to the recovery room. A CT scan is done that night, and the patient spends the night in either the neurosurgical intensive care unit or step-down unit. The next day, the patient moves to the neurosurgical floor and is encouraged to get up and walk around. Most people go home 2 days after the operation.

Patients who have a single electrode placed undergo placement of the implantable pulse generator on the same day. This is done under general anesthesia (completely asleep). Patients who have 2 electrodes placed will have 2 generators placed approximately 1 week later during a separate overnight admission to the hospital.

What is frameless deep brain stimulation?

Northwestern Memorial Hospital is one of the few centers in the country (and the only one in the Chicago region) offering deep brain stimulation using a new technology that avoids the use of the stereotactic frame in certain patients. Dr. Rosenow, Director of Functional Neurosurgery, helped to develop and validate the accuracy of this innovative technology that makes the surgery more comfortable and speeds the start of the procedure. Instead of using a frame, the procedure uses 4 small posts that are attached to the skull through very small incisions. Patients usually feel no discomfort at all during this part of the procedure. These posts may be placed up to several days before the actual operation. The patient then undergoes CT and MRI scanning as usual. Since all the imaging may be completed before the morning of surgery, all the planning may be done ahead of time as well. In the operating room, the patient's head does not have to be firmly fixed to the operating table, as it is with the stereotactic frame. Instead, the patient's head and neck are supported by a soft cradle. The patient may move around a bit as needed during the procedure to relieve stiffness and spasm. Some patients having electrodes placed on both sides can actually get up between portions of the procedure! This new technique has been shown to be just as accurate as the traditional method using the stereotactic frame.

What are the results of thalamic deep brain stimulation for tremor?

Deep brain stimulation can dramatically reduce hand tremor in those people with essential tremor. In many cases, the tremor can be eliminated. Most people acquire at least 75% relief. This may last for many years, with occasional programming adjustments needed to maintain the effects.

Tremor due to other causes (multiple sclerosis, brain trauma) is more difficult to control, requires more frequent programming adjustments, and may only provide 50% tremor relief. However, this may be a significant aid to someone who is disabled by tremor.

What are the results of subthalamic deep brain stimulation for Parkinson's disease?

In general, deep brain stimulation helps put people with Parkinson's into their best “on” state and keep them there for 2 to 3 times as long.

Studies have shown that deep brain stimulation can improve the symptoms of Parkinson's disease by about 60%, while allowing some patients to cut medication use in half or more.. The amount of useful “on” time may increase by 2- or 3-fold, meaning that if each dose of medication previously worked for 1 hour, with stimulation it may last 2 or 3 hours. In addition, fluctuations are smoothed out and are not as sharp, meaning that “off” periods are not as disabling. Moreover, these “off” periods are more predictable than without stimulation. Because not as much medication is needed, dyskinesias are improved as well.

It typically takes about 3-6 months of programming before reaching a final steady state between adjustments in the stimulation and the medication.

It is important to remember that DBS is not a cure for Parkinson's, but merely a way to relieve the symptoms. As far as is known, it does not speed up or slow down the progression of the disease.

What are the results of deep brain stimulation for dystonia and torticollis?

Published data of patients with dystonia undergoing deep brain stimulation are smaller than those for tremor and PD. However, dystonia and torticollis also appear to respond well to stimulation. While many dystonias respond well to stimulation, patients with certain genetic forms (such as those due to changes in the “DYT” genes) do especially well. Generalized dystonia and cervical dystonia (torticollis) can improve by as much as 75%.

What are the risks of deep brain stimulation?

Any operation carries certain risks. It is important to know these before undergoing the procedure. For example, some people do not get as much relief as others. This may be due to a variety of reasons (each individual's anatomy is different, diseases progress, etc.). There is a risk of bleeding in the brain (about 1-2%) which is usually asymptomatic but can have serious consequences. The risk of breakage of the device is about 1%. Infection happens about 5% of the time in any operating room procedure.

What about stem cells and gene therapy?

Unfortunately, none of the large stem cell trials in humans have been successful enough to merit moving to widespread use of the technique. A new technique is being studied in a few patients around the world involving implanting a catheter deep into the brain and infusing a substance called GDNF (glial-derived neurotrophic factor) that will either halt or reverse the progression of Parkinson's disease. This intervention is still several years away from common use, even if the early trials are successful. However, having deep brain stimulators should not stop a patient from having access to these sorts of treatments, once they are proven.

The Northwestern University/Northwestern Memorial Hospital Movement Disorder Surgery Program

Northwestern Memorial Hospital Movement Disorder Surgery Program brings together the advanced resources of Northwestern Memorial Hospital and Northwestern University School of Medicine, one of the nation's premier institutions for research into movement disorders. The school was recently named by the National Institutes of Health as one of only 12 centers in the country to receive the prestigious Morris K. Udall Center grant for Parkinson's research. In addition, we team with the Rehabilitation Institute of Chicago, the nation's best rehabilitation center.

The Northwestern University Parkinson's Disease and Movement Disorders Center provides comprehensive resources, education, evaluation, and treatment for patients with all types of movement disorders.