Deep brain stimulation: A new procedure just available in town

Deep brain stimulation: A new procedure just available in town

 

Dr. Supakorn Rojananin

                                                Deputy Dean of public relation and special affairs

                                                Faculty of Medicine Siriraj Hospital

                                       

 

            Recently, neurosurgeons at Siriraj hospital had accomplished a new procedure named “Deep brain stimulation” which was done in two patients who were suffering from Parkinson’s disease. This could bring some hope for the patients to have a better quality of life and to resume their normal life activity properly again. 

            Parkinson’s disease is a chronic progressive neurodegenerative movement disorder characterized by tremor, rigidity, slow movement, poor balance, and difficulty walking. Doctor James Parkinson, an English physician was the first who described this illness in 1817. In the past, it was incurable disease and the symptoms gradually progressed until the patients were bed ridden and succumb to death with complications.

            The incidence of Parkinson’s disease in Thailand is unknown but it afflicts 1 to 1.5 million people in United States.  It is more commonly found in older age of all sexes with an average of 60. It is rare in people younger than 30 and only 5 to 10% of patients experience symptoms before the age of 40.  At present, an average age of Thai people is around 65, every one who become older, no matter who you are, may have a chance to be affected by the disease.

            Parkinson’s disease results from the degeneration of dopamine producing nerve cells in the brain, especially in the substantia nigra and the locus coeruleus. Dopamine is a neurotransmitter that stimulates motor nerve cells that control the muscles.  When dopamine production is depleted 80% or more, the motor nerve cells are unable to control movement and coordination, thus, the symptoms appear. The exact cause of nerve cell degeneration is unknown. Many factors are involved such as, aging, anti-depressive drugs, environmental toxins, brain trauma, vascular occlusion, brain hemorrhage or infection and in heredity.

            Parkinson’s disease has its own clinical characteristics which is not difficult to recognize. Several symptoms develop over time. There were 4 typically primary symptoms i.e., bradykinesia (slow movement), tremor, muscular rigidity, and parkinsonian gait. 60-70% of the patients began with tremors in the hand, finger, forearm, or foot which typically tend to shake at rest but not when performing task. Bradykinesia is slowness in voluntary movement. Patients may find difficulty to initiate movement as well as to complete it once it is in progress making them vulnerable to injury.  Muscular rigidity or stiff muscles may produce muscle pain and an expressionless or mask-face which tend to increase during movement. 

            According to the management of the disease, Professor Dr. Niphon Puangwarin (Chief of Division of Neurology, Department of Medicine, Faculty of Medicine Siriraj Hospital), there is no curative treatment for this disease. Medication aims to relieve the symptoms and improve the quality of life. In severe cases, some types of surgery may lessen tremors. Since medication selection and dosage are tailored to individual and some drugs may have side effects for long term use, medical consultation and periodic follow-up is mandatory. Before prescribing drug regimen, physicians will consider factors such as severity, age, and presence of other conditions. No two persons respond identically to a particular drug or a dosage level. In severe cases that are not respond well to medical treatment or having intolerable side effects, surgery is another method of controlling the symptoms and improving the quality of life. Deep brain stimulation (DBS) is a new surgical procedure that is just available in Bangkok.

            Dr. Nantasak  Tisawipath (Chief of Division of Neurological Surgery, Department of Surgery, Faculty of Medicine Siriraj Hospital) discloses that DBS is a surgical procedure to implant a battery-operated, high technology device called neurostimulator , similar to heart pacemaker, to the targeted area in the brain that control movement. This device will deliver electrical stimulation to block the abnormal nerve signals that cause tremor and PD symptoms. DBS device consists of three components, the electrode, the extension and the neurostimulator. The tip of the electrode is positioned within the targeted brain area by inserting through a small opening in the skull with an extension of wire passing down in the neck and connecting to the battery packed neurostimulator in the upper chest. The battery must be replaced every 5 years.

            Dr. Nantasak says the DBS procedure does not damage healthy brain tissue but stimulates the nerve cells, thus it is reversible in the future without causing major complications.

            However, to select the patients eligible for surgery, to identify and localize the targeted area in the deep brain and to calibrate the current of the neurostimulator are somewhat complicated matters that need collaboration between imaging-neuroradiologists, neurosurgeons and neurologists and the patients themselves.

            According to the National Institute of Neurological Disorders and Stroke, New York, many patients who had DBS procedure experience considerable reduction of their PD symptoms and some are able to greatly reduce their medications. Although DBS is not the answer of all questions of PD, however, in the near future, DBS could lighten the dark side of the disease and bring some hope for many Thai PD patients to resume their normal activity again.