Deep brain stimulation
What is treated with deep brain stimulation (DBS)?
Motion disorders are treated with deep brain stimulation if they are caused by Parkinson´s disease, essential tremor (ET) or dystonia, if they could not be sufficiently treated with other therapies, or if the disease is very progressive. Severe psychiatric diseases have also been treated successfuly with DBS.
The contemporary surgical aiming points of DBS are:
How does deep brain stimulation (DBS) work?
During deep brain stimulation surgery, electrical electrodes are implanted in brain regions which have specific functions within the regulatory circuit of body movement. These brain areas are stimulated by using high-frequency, pulsatile, monopolar or bipolar electrical impulses. As a result, it is possible to selectively switch brain areas on and off. Symptoms can, thus, be switched on or off or at least reduced. The most important feature of DBS is that the function of the brain areas is sustained and the effect of the stimulation is reversible at any time. Despite of its clinical efficiency, the detailed mechanism of action in terms of motion disorder treatment with deep brain stimulation remains unknown.
The advantages of deep brain stimulation
The main advantage of deep brain stimulation in comparison to other procedures which destroy or remove brain tissue (pallidotomy, thalamotomy) is to adjust the stimulation subject to its effect. DBS is reversible without destroying or removing a huge amount of brain tissue. DBS does also not entail the partially grave side effects of drugs used to treat Parkinson´s disease, essential tremor (ET) or dystonia. In opposite to many neurological diseases forcing the neurosurgeon to operate a patient as quickly as possible due to the progress of the disease, deep brain stimulation surgery can be planned well in advance.
Deep brain stimulation surgery / DBS surgery
Few days before surgery
Few days before surgery, the head and the brain are examined using MRI. The images enable the surgeon to exactly plan the access and aiming points as well as the 3D access. The surgery can be simulated to minimize its risks. This examination is accompanied by further examinations and talks about the surgery, how long patients must have an empty stomach before surgery, about which drugs can still be taken, etc.
To implant the electrodes, a so-called stereotactic surgery has to be carried out. This is a minimally invasive surgery during which the head is fixed in a stereotactic frame in local anesthesia. The stereotactic frame serves to hold the head in an exact position.
The skull is then opened by drilling a small hole through which combined stimulation and lead electrodes are guided 10 mm before the aiming point. By performing electrophysiological examinations, the aiming points are identified by amplifying and measuring nerve cell activity (e.g., subthalamic nucleus). Neurological examinations can take place during the whole procedure because patients are awake. The effects of the stimulation can be controlled this way.
The quadripolar stimulation electrode is now inserted into the aiming point, controlling its location by X-raying, fixed at the drilling hole and its final location documented by an X-ray image. The skin wound is closed and the stereotactic frame is removed after the removal of all instruments and devices.
For the next days, a test period begins during which the patient has a remote control to test the effect of the deep brain stimulation. Furthermore, the final location of the stimulation electrodes is controlled in an MRI examination.
Implantation of the pulse generator
If the test period is successful and the positive effects are constantly repeatable, the impulse generator is implanted under the skin area around the collarbone using general anesthesia. In single cases, the implantation of the pulse generator takes place during the first operation together with the implantation of the electrodes.
Return to work after deep brain stimulation (DBS) surgery
Patients can return to work 3-4 weeks after surgery.
Return to sports activities after deep brain stimulation (DBS) surgery
Sports activities can be resumed 3-4 weeks after surgery.
Results and risks of the deep brain stimulation (DBS)
The risk of intracranial bleedings within the scope of the deep brain stimulation ranges between 0.6 % and 3.5 % in scientific publications. The rate of infections and wound healing disorders amounts 2.5 %. Mechanical or technical complications related to the specific implant vary between 5.8-17.7 %. Undesirable motor or psychomotor effects are more frequent in the initial phase of the stimulation. But they are not very distinctive and react well to the variation of stimulation parameters. The technological progress, the improvement of imaging procedures and optimized courses of action continuously contribute to the decrease of complication risks.