A couple of years ago, the first short movie sequences of Parkinson-patients with a deep brain stimulator implant were published and the professional world was amazed. Sclerotic patients in their "off-phase" started moving again and – in the word's most deepest meaning – at the push of a button. Before long, the neurologists started making first experience with brain stimulation with other indications.
A baton against pain
Cluster-headache has become one of the most interesting fields. It is a chronic headache with characteristic one-sided pain attacks, lasting from a couple of minutes to several hours. The pain level reached is one of the highest possible in the human body. The calcium antagonist Verapamil helps only some of the patients. But others, mainly those with a chronic history, do hardly react to any therapy. Some patients even prefer committing suicide. So it doesn't really come as a surprise, that therapeutic novelties such as deep brain stimulation (THS) do draw such an attention, although Cluster-headache is one of the scarcest chronic pain syndromes with a prevalence of one one-hundredth per mille only.
The THS "tickles" the central pacemaker of the Cluster-pain in the lower hypothalamus electronically. Thanks to Positrone Emission Tomography (PET), neurologists know about those pacemaker centers at all. When examining patients during an attack, the physician finds an area the size of a hazelnut deep in the brain. This became the target region for the stereotactic implantation of the THS electrode. An Italian working group in Milan made the most experience with the new procedure. Just a short while ago, they submitted long-term results of 16 patients and provided an impressive evidence of success. Dr. Massimo Leone and his colleagues reported in the professional journal Neurology. The patients were under observation for an average of 23 months. "After that time, 13 out of 16 patients were still either completely or nearly free of pain", Leone reports. In the other cases, the pain was at least relieved.
Dangerous rank growth in Cluster-surgeries?
The success of the Italians and of other working groups resulted in more THS implantations made in German neurosurgical centers as well. "Some of the Cluster patients are operated on rather prematurely, sometimes even without a neurologist" criticizes Assistant Professor Arne May, head of the Kopfschmerzambulanz (headache outpatient's department) at the University Hospital in Hamburg-Eppendorf. Only a small number of Cluster patients, in particular those with therapy resistant, chronic and non-episodic ailments, is suitable for this procedure. A limitation to extreme cases makes sense – although not a lot of Cluster patients have been operated on yet, the physicians already had to face one fatal case during surgery. And there is no guarantee to reach the desired results. "Those reports of success have raised enormous expectations in the patients. But it quite often cannot be delivered", says May during his interview with DocCheck-Newsletter. He warns vividly not to fall for the treacherous hope, that after a THS electrode implant, all you have to do is switch a button and all problems will be solved. Without a systematic attendance before and after, the THS implant easily might be a failure. It could take months to set the stimulator exactly right. And every change or reset requires weeks of observation afterwards, until the change is perceptible.
Whoever does a good job, hits up to 70 percent
For now, this type of systematic attendance afterwards seems to be in short supply in Germany. "The Italians do a better job, that's why the results are good there", emphasizes May. In Germany, some of the neurologists are using the PR effect of deep brain stimulation on Cluster patients without being able to guarantee the necessary attendance afterwards, for example, for patients living hundreds of kilometres away from the physician's office. But despite his criticism, May is happy about the new procedure: "THS is an excellent method for Cluster patients, in particular those who could not be helped otherwise. And the chances for success are at about 70 percent."