Deep brain stimulation in Zurich
The team at the USZ has been successfully performing deep brain stimulation since 2009 and is now by far the largest center for deep brain stimulation and functional neurosurgery with the most procedures per year in Switzerland. In addition to the treatment of movement disorders such as Parkinson’s disease or tremor, new indications such as epilepsy (2012) or severe depression (2013) were also treated at the USZ for the first time nationwide.
Close cooperation has been established with the Cliena Schlössli Private Clinic and the Lengg Clinic for the treatment of psychiatric indications and refractory epilepsy. A special feature of the team at the USZ is that an individual treatment plan is drawn up for each patient and coordinated on an interdisciplinary basis between neurologists, neurosurgeons and psychiatrists. This ensures that patients receive the best possible treatment for them. All the escalation therapies known today, such as deep brain stimulation, focused ultrasound, radiofrequency ablation and pump therapies, are available to us for this purpose.
What is deep brain stimulation?
Deep brain stimulation (DBS) is a treatment in which fine electrodes are surgically inserted into the brain. These electrodes permanently transmit electrical impulses to strategically important locations in the brain, thereby influencing the functions of the affected brain region and the associated structures. The electrode in the left side of the brain improves the symptoms on the right side of the body and the electrode in the right side of the brain improves the symptoms on the left side of the body.
They are connected to the actual pacemaker, which in most patients is implanted in the collarbone or abdominal area, by a cable that is invisible under the skin.
History of deep brain stimulation
| 1986 |
First deep brain stimulation for tremor patients in the thalamus (Grenoble, France) |
| 1993 |
Deep brain stimulation for Parkinson’s patients in the subthalamic nucleus (Grenoble, France) |
| 1994 |
Deep brain stimulation for Parkinson’s patients at the Pallidum (Zurich, Switzerland) |
| 1995 |
Approval for the treatment of essential tremor in Europe |
| 1998 |
Approval for Parkinson’s disease in Europe |
| 2003 |
Approval for the treatment of dystonia in Europe |
| 2009 |
Approval for the treatment of obsessive-compulsive disorder in Europe |
| 2010 |
Approval for the treatment of epilepsy in Europe |
For which diseases can deep brain stimulation be used, and with what success?
| Disease |
Target symptoms |
Target point |
Success |
| Parkinson’s disease |
Tremor (shaking) that does not respond well enough to medication |
STN, Vim |
- Improvement of the tremor
- Reduction of motor fluctuations
- Reduction of the drug dose (for subthalamic stimulation) and its side effects
|
| Motor fluctuations (alternation of under- and over-movements) |
STN, GPi |
| Tremor disorders |
Tremor (shaking) that does not respond well enough to medication |
Vim |
- Improvement of the tremor
- Minimization of drug side effects
|
| Dystonia disorders |
Dystonia (persistent muscle tension) that does not respond well enough to medication |
GPi |
Legend: STN: subthalamic nucleus, Vim: ventromedial nucleus of the thalamus, GPi: globus pallidus internus.
Scientifically investigated indications in psychiatry
| Disease |
Target symptoms |
Success |
| Depression |
Depression that cannot be treated sufficiently well with medication and electroconvulsive therapy |
Majority of treated patients respond well to treatment |
| Obsessive-compulsive disorder |
Obsessive-compulsive disorders that cannot be treated sufficiently well with medication |
Majority of treated patients respond well to treatment |
| Tourette syndrome |
Severe tic disorders that cannot be treated sufficiently well with medication |
Good results in studies, but must be considered experimental overall |
| Alzheimer’s disease |
Cognitive deficits in the context of Alzheimer’s dementia |
Still insufficient data, must be considered experimental |
Scientifically investigated indications in neurology
| Disease |
Target symptoms |
Success |
| Epilepsy |
Epilepsy disorders that cannot be treated sufficiently well with medication |
Reduction in the frequency and severity of epileptic seizures |
| Pain |
Severe chronic pain syndromes that cannot be treated sufficiently well with medication |
Pain reduction, must be considered experimental depending on the pain syndrome |
Surgery under anesthesia or awake?
The electrodes for deep brain stimulation can be implanted either under anesthesia or while the patient is awake. Both techniques are available to us. Awake surgery requires a little more time in the operating theater and a particularly experienced and well-coordinated team. On the other hand, it offers the enormous advantage over surgery under anesthesia, which has become popular at some centers in recent years, that the effects and side effects of the therapy can already be precisely assessed in the operating room.
During the operation, it is still possible to react to these and thus achieve the best possible treatment result for the patient. The disadvantages are the psychological strain on patients due to the experience of the operation without anesthesia and, in the case of Parkinson’s disease, the need to discontinue medication beforehand. Thanks to our many years of experience and the close personal contact between the treatment team and the patients, the operation is almost always unproblematic when the patient is awake. We advise each patient individually and, if necessary, perform the procedure under anesthesia.
Preliminary and follow-up examinations
In order to select patients for treatment in the best possible way and for rigorous quality control, various examinations are required before the operation and 6 months afterwards. The aim is to ensure that treated patients have the best possible chances of achieving the best possible result with as few side effects and complications as possible.
| Investigation |
Before surgery |
6 months |
| Motor skills laboratory: symptoms without and with medication effect* |
X |
X |
| High-resolution MRI of the brain |
X |
|
| Psychiatric examination |
X |
X |
| Neuropsychological examination |
X |
X |
| Sleep laboratory examination |
X |
X |
| EEG examination (brain waves) |
X |
X |
| Speech therapy (speaking, swallowing) |
X |
X |
| Physiotherapy (walking, standing) |
X |
X |
| Heart/lung/blood tests |
X |
|
| Dental check-up (recommended) |
X |
|
* The L-dopa test examines whether Parkinson’s symptoms improve significantly with high-dose levodopa medication. The result of this test allows an assessment of the potential gain from surgical therapy and thus plays an important role in the decision on surgery. The alcohol test examines the extent to which a tremor changes after consuming alcohol.
The examination results are discussed in detail with patients and their loved ones before the operation and they are informed about the advantages and disadvantages, opportunities and risks. Only then will a final decision be made about the operation.
All about the operation
Preliminary discussion:
Deep brain stimulation represents an important turning point in the life of a patient and their relatives. Information about the treatment is provided in many places. Unfortunately, much of this information is contradictory and confusing. For this reason, we attach great importance to a joint discussion between neurologists (Prof. Baumann), neurosurgeons (PD Dr. Stieglitz, Dr. Oertel), patients and relatives, in which we explain the treatment indication, the procedure, the course of treatment, opportunities and risks in detail.
Before the treatment:
The decision for or against treatment is then made. The patient enters the hospital one to two days before the procedure. In this context, medication can be gradually reduced for Parkinson’s patients, for example.
Before the operation:
Aspirin (ASA/acetylsalicylic acid) and other blood-thinning medication must be completely discontinued in good time in accordance with the neurosurgeon’s instructions (e.g. aspirin: 7 days before surgery).
Change of medication as determined by the treating neurologist.
Admission to hospital:
1-2 days before the procedure.
Operation, 1st part:
Insertion of electrodes during awake surgery, usually on the 2nd day of hospitalization
Operation, 2nd part:
Insertion of the pacemaker under short anesthesia, usually on the 4th-6th day of hospitalization
After the operation:
After the operation, you will be hospitalized for about 1 week. During this time, the pulse generator is slowly activated. It is important to note that this process can take a long time and can take several weeks to months in total. Tremor patients can usually go home afterwards. Rehabilitation is usually sensible and strongly recommended for Parkinson’s patients.
Follow-up checks:
Approximately 6 weeks after the procedure, a follow-up check is carried out in the neurosurgical consultation. The wounds are checked and the general success of the treatment is assessed. Further check-ups take place in the Parkinson’s consultation hours of the neurology clinic, usually every month for the first six months after the operation. Six months after the operation, many examinations that were already carried out before the operation are repeated – this serves to ensure the quality of the procedure, but also to customize the treatment.
Possible risks of deep brain stimulation
We ask patients to wash their hair thoroughly before the operation and to comb it well, especially if it is long. The entire first part of the operation is performed while the patient is awake.
On the morning of the day of the operation, the scalp is anesthetized by injecting a local anesthetic in several places around the head. A stereotactic frame is then attached to the skull through the skin using four screws. This procedure is not painful thanks to prior anesthesia. The frame remains attached to the head until the end of the operation (for about 3 hours).
In the operating room, the hair is carefully parted and only minimally shaved in the area of the operation. After careful disinfection and sterile draping, the actual operation begins.
A neurosurgical drill is used to make a 14 mm diameter opening in the skull. This is not painful, takes a few seconds and is perceived as a loud noise due to the direct transmission of the vibrations of the device to the hearing organs in the skull. One or more fine electrodes are now inserted through this opening to the planned target point. The recording of brain waves from the tip of the electrode allows the accuracy of the procedure to be checked and optimized.
During a test stimulation, the neurologist checks the effectiveness of the stimulation and the occurrence of any side effects. The aim is to achieve a good effect with little stimulation, while side effects only occur with strong stimulation. This allows greater scope for programming the stimulator later on.
The neurosurgeon now replaces the test electrode with an electrode with several contacts at the tip, which should remain permanently in the target region. It is attached to the bone and the drill hole is closed at the same time. Immediately afterwards, the entire procedure is repeated on the other side of the head. A computer tomography of the head finally confirms the correct electrode position on both sides and the stereotactic frame can be removed.
Depending on the condition to be treated, we implant the pacemaker on the same day or about two days later under anesthesia. The procedure takes another 30 minutes.
Possible surgical risks of deep brain stimulation
Deep brain stimulation is one of the procedures with the lowest complication rate in neurosurgery. All the possible consequences that we list here are very rare. Nevertheless, it is important to be aware that serious complications can also occur during this operation and that there is a risk of severe neurological disorders or even death.
- Persistent pain or fluid accumulation at the implantation site of the pacemaker.
- Infections and colonization of electrodes and pacemakers with bacteria occur in up to 3% of patients during the first year after implantation and necessitate temporary removal of the system and treatment with antibiotics.
- Seizures can occur in 1-3% of cases.
- General medical complications, such as a blood clot in the lung, are seen in 1%.
- Fatal consequences due to one of the above complications occur in less than 0.5% of cases in comparable operations
We ask patients to wash their hair thoroughly before the operation and to comb it well, especially if it is long. The entire first part of the operation is performed while the patient is awake.
On the morning of the day of the operation, the scalp is anesthetized by injecting a local anesthetic in several places around the head. A stereotactic frame is then attached to the skull through the skin using four screws. This procedure is not painful thanks to prior anesthesia. The frame remains attached to the head until the end of the operation (for about 3 hours).
The following disorders can occur temporarily or permanently, depending on the site of stimulation in the brain:
| Side effect |
STN |
Vim |
GPi |
| Speech disorder (slurred speech) |
++ |
+ |
+ |
| Change in walking |
+++ |
+ |
++ |
| Unlearning to swim/ski |
+ |
|
|
| Sensory disturbances |
+ |
+ |
+ |
| Coordination problems |
+ |
++ |
+ |
| Muscle cramp/stiffness |
+ |
|
|
| Double vision/blurred vision |
+ |
|
+ |
| Change of mood |
++ |
|
+ |
| Temporary excess movements |
++ |
|
|
| Parkinsonism |
|
|
+ |
Legend: STN: subthalamic nucleus, Vim: ventromedial nucleus of the thalamus, GPi: globus pallidus internus. +++: >20%, ++: 10-20%, +: <10% (Zurich experience).
Most of the side effects caused by pacing disappear after reprogramming or switching off the pacemaker
Chances of success
For all diseases that can be treated with deep brain stimulation, the main aim is to improve quality of life by reducing symptoms. This means that deep brain stimulation is not a treatment that leads to the cure of a disease, but to the alleviation of symptoms (so-called symptomatic treatment). In the case of the classic and best-studied diseases worldwide (Parkinson’s, tremor, dystonia), there is a high probability that the symptoms can be significantly alleviated. The Zurich figures confirm this, for example, in the most frequently performed deep brain stimulation for Parkinson’s patients: here we see a very clear improvement in quality of life in over 85% of patients. The remaining patients also experienced an improvement in symptoms, albeit to a lesser extent. On average, drug treatment is reduced by two thirds in Parkinson’s patients after deep brain stimulation, and even more significantly in tremor patients.
Side effects
It is possible that the electrical field of deep brain stimulation stimulates nerve cells that you do not actually want to stimulate. This can lead to side effects. Depending on the disease, the most common symptoms are speech disorders (slurred speech) or problems with walking. Other side effects such as visual disturbances occur much less frequently. Overall, these side effects can be reduced or avoided in most patients through appropriate programming. Experience in Zurich shows that the full stimulation effect cannot be achieved in around 8-10 percent of patients because side effects would occur. Other side effects may result from the change in medication. For example, the reduction in Parkinson’s medication can lead to a certain degree of apathy, at least temporarily.
