Deep brain stimulation (DBS) for parkinsons disease
December 4, 2015
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Deep Brain Stimulation (DBS) for Parkinson's Disease ....
Parkinson’s disease (PD) is a neurological disorder caused by degeneration of dopaminergic neurons resulting in reduced levels of dopamine in the brain. It affects almost 1% of people especially in the western countries above the age of 50 years with a male preponderance (male/female ratio 3:2). It leads to symptoms such as tremors at rest, rigidity of the limbs and slowing of movements (bradykinesia). It can also lead to postural instability, micrographia and mask-like facies. The walk is also abnormal leading to small shuffling steps (marche a petits pas). This disease is named after an English doctor by name James Parkinson in the year 1817.
PD is a type of movement disorder where the symptoms begin gradually, often on one side of the body and later affecting both sides. As the symptoms get worse, these patients will develop trouble while walking, talking or doing simple tasks of daily living. They can also have depression, sleeplessness, or trouble chewing and swallowing. There is no cure for this disease, however, a variety of medicines help such patients improve dramatically. Surgery and deep brain stimulation (DBS) can help in severe cases especially in those who do not respond to medical treatment or develop too many side effects.
DEEP BRAIN STIMULATION (DBS)
Deep brain stimulation (DBS) is a minimally invasive surgical procedure used to treat the debilitating symptoms of Parkinson’s disease (PD) such as tremor, rigidity, stiffness, slowing of movements and gait disturbances. DBS uses a surgically implanted, battery-operated medical device called an implantable pulse generator (IPG). This is similar to the pacemaker in the heart, approximately the size of a stop-watch which is designed to deliver electrical stimulation to specific areas in the brain that control movement. This in turn blocks the abnormal nerve signals that causes the symptoms in Parkinson’s disease.
The Neurosurgeon uses the MRI or the CT imaging to identify and locate the exact target within the brain for the surgical intervention. Usually the areas identified are the thalamus, sub thalamic nucleus and the globus pallidus. The DBS has three components : the lead (also called the electrode), the extension (insulated wire) and the IPG. The electrode is inserted through a small opening in the skull, and it’s tip is positioned within the specific area of the brain. The insulated wire connects the electrode to the IPG which is placed subcutaneously near the collar bone in the upper chest. Once the system is in place, the electrical impulses are sent from the IPG to the electrode (lead) inside the brain. These impulses block the abnormal electrical signals thereby alleviating the Parkinson’s symptoms.
Most patients after DBS in PD experience considerable reduction of their motor symptoms and are able to reduce their medications. It can also reduce dyskinesias induced by Levodopa on long-term use. DBS changes the trigger pattern in the brain, but does not slow the progression of the neurodegeneration. Researchers are still continuing to study DBS and to develop ways of improving it !
SPINE TUBERCULOSIS........a treatment protocol !
Tuberculosis is one of the most common diseases that affects the spine. Though it is quite common in the eastern part of the globe, it is prevalent in the Western hemisphere too. It’s incidence is high among the people who are poorly nourished, living in a crowded area or in a subnormal living condition. It also affects the immunocompromised, elderly and the diabetic population.
The first documented case of spine tuberculosis dates back to 3000 years old Egyptian mummies. However, the first case was described in the modern era by a British surgeon by name Percival Pott in the year 1779. And therefore spine Tuberculosis (TB) is also called as the Pott’s disease. Though spinal involvement with tuberculosis is less than 1% of patients who are diagnosed to have TB, it can pose as a major problem producing neurological deficits and spinal deformities. The lower thoracic and upper lumbar vertebrae are the most commonly affected spinal region, though it affects the cervical spine and craniovertebral (CV) junction as well.
Pott’s disease (Spine TB) usually results from the spread of tuberculous bacillus from other parts of the body through bloodstream (hematogenous route). The infection reaches the edges of the vertebral bodies and spreads to the adjacent disc as well. If left untreated, the disease leads to destruction of the vertebral body and ultimately deformity and paralysis. Neurological deficits develop in 10 to 47 % of patients who have a spine tuberculosis.
DIAGNOSIS AND TREATMENT
The blood test will show an elevated ESR (Erythrocyte Sedimentation Rate) with increase in the WBC counts. A positive Tuberculin skin test in 90 % of the patients are seen with Pott’s disease. Computed tomography (CT) spine, Bone scan and MRI can pick up early diseases affecting the spinal column. Most of these patients can be treated with antituberculous (ATT) drugs along with analgesics and various immobilisation methods using braces and collar. Despite the use of antituberculous drugs in proper doses & schedule, 10 % of the patients will need surgery to drain a tuberculous abscess (psoas abscess), debridement of the epidural granulation compressing the spinal cord and corpectomy (removal of the diseased vertebral body) with spinalstabilisation (fusion) using Titanium implants.
PROGNOSIS
Early diagnosis and adequate medical treatment with ATT for all patients with spine tuberculosis is a MUST ! Patients must comply with the treatment protocol sincerely without skipping drugs especially when the spine is involved. In patients where there is poor response to conservative management, those with progressive neurological deficits and spine deformities should seek neurosurgical intervention at the earliest for good outcome.
