Deep Brain Stimulation for Treatment of Parkinson’s Disease Deep brain stimulation, Parkinson’s disease, subthalamic nucleus, stereotactic surgery

摘要

With the evolution of deep brain stimulation (DBS), stereotactic operative treatment of drug resistant Parkinson’s Disease experiences a renaissance. Refined operative techniques using computerized image-fusion programs, intraoperative microrecording and macrostimulation have made the targeting of the region of interest easier. Deep brain stimulation of the subthalamic nucleus is able to reduce major symptoms as tremor, rigor and bradykinesia. Short and middle-term as well as long-term studies have confirmed these results.The rate of intra- and perioperative complications is around 1-2%. However, during the follow-up period hardware-related complications can increase to 4-20%. This is an overview about history, indications, operative technique and results of deep brain stimulation based on the actual literature. Introduction During last years surgical procedures have played an important role in the treatment of drug-refractory central movement disorders. Spiegel und Wycis (24) introduced the stereotactic techniques in neurosurgery: it allows to hit every brain area three-dimensionally in a range of millimeters. In the beginning the application of this procedure was used to treat patients with severe pain syndromes (22). This was followed by interventions in patients with movement disorders and psychiatric diseases. Lacking alternative treatment the so-called “stereotactic lesional procedures” by damage of intracerebral nuclei were the method of choice in the late sixties (13,15). However, with the introduction of Levodopa, there was a loss of interest in stereotactic neurosurgery. Over a long time patients with tremor which was drug resistant remain the only indication for “thalamotomy”, whereas in bilateral tremor one side was left untreated.In 1986 Benabid performed for the first time a combination of unilateral thalamotomy and contralateral thalamic stimulation in a patient with bilateral tremor (2). The results were such successful, that Deep Brain Stimulation (DBS) of the Ventral intermediate nucleus (Vim) of the thalamus has been applied as first choice operative treatment for tremor in the following years (1). The EC-certification for this indication was obtained in 1995.Using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkey model, Benazzouz et al. (4) found in 1993 that high frequency stimulation of the nucleus suthalamicus (STN) has a remarkable positive effect on rigor and bradykinesia. This resulted in a change of paradigm for operative treatment of PD. The STN was defined as the new target for DBS (3/18), since it influences positively not only Tremor, but also akinesia and rigor. The EC-certification of DBS for the operative treatment of tremor, rigor and akinesia was obtained in 1998. The great advantage of this procedure versus lesional procedures is the simultaneous stimulation of both hemispheres and/or different target points. Moreover side effects are reversible by regulation of stimulation parameters (7/11) and future treatment options e.g. neurotransplantation are not excluded.The exact mechanism underlying the beneficial effect of DBS is still unclear and remains a field of active research. It seems to be a combination of inhibition of neurons, modulation of abnormal patterns of activity, and activation of axons (19). Indications and Contraindications Besides Parkinson Disease (PD), dystonia and tremor of different origin are the standard indications for DBS. Stereotactic treatment of other neurologic-psychiatric diseases as cluster-headache, epilepsy or obsessive-compulsive disorders (OCD) is actually experimental.The table 1 gives shows the indications for DBS in PD patients. Table 1: Indications for DBS in Parkinson’s DiseaseContraindications are dementia or psychotic disorders, multiple system atrophia (MSA) and other neurological diseases such as brain tumors or brain atrophy. Furthermore internistic pathologies e.g. coagulation disorders preclude the operative procedure.Operative Techn