Deep brian stimulation (DBS) implantation
Parkinson’ disease (PD) is the second most common neurodegenerative disorder after Alzheimer’s disease (AD). Chief symptoms of PD are trembling of the limbs (resting tremor), muscular stiffness (plastic reigidity), and slowness of bodily movement (bradykinetia). Parkinson’s disease is a progressive disease of CNS, in which the involvement of the dopaminergic neurons of the substantia nigra (SN) results in significant dopamine depletion in the corpus striatum. The deterioration of the substantia nigra may have a variety of causes, including injuries by a tumor, a stroke, a chemical agent, or even a virus infection. However, the causes of PD are still unknown, and the disease only affects a selective systems of nerve cells. Although the average age of PD patients is about 60 years, population under the age of 40 can still be affected. According to the survey of Health Canada , approximately 1 in 100 Canadians over the age of 60 are diagnosed with this condition. The number of people dying from Parkinson’s disease has quadrupled in the last 20 years.Chronic deep brain stimulation (DBS) is approved by FDA in 2002 as an alternative treatment for motor function disorders. Ventrointermedius externus (Vim), globus pallidus interna (GPi), and subthalamic neuclues (STN) are the most popular surgical target loci for the treatment of Parkinson’s disease while most techniques are developed for STN stimulation. The subthalamic nucleus (STN) plays an important role in the basal ganglia-thalamocortical motor circuit. Considered as the main “driving” factor in basal ganglia, STN utilizes the excitatory neurotransmitter glutamate and innervates both basal ganglia output nuclei, the internal segment of the globus pallidus (GPi) and the pars reticulata of the substantia nigra (SN). The generation of the abnormal patterns of activity observed in Parkinson’s disease and essential tremor is thought to be caused by the hyperactivity of the STN. Therefore, interruption of STN activity by creating a small lesion or using high frequency deep brain stimulation (DBS) can reduce motor abnormalities such as tremor, rigidity, bradykinesia, postural instability, and akinesia.