Deep-brain stimulation holds hope in treating Parkinson’s disease

Deep-brain stimulation (DBS), a neurosurgical procedure that helps people with abnormal body movements like epilepsy, dystonia, Parkinson’s disease (PD) and tremor, is gaining ground in India. DBS is not new, but now there is better awareness and improvements in the technique.

Recently, we had a 68-year-old patient with advanced Parkinson’s disease, and highly abnormal bodily movements. With DBS, he was able to regain control of his movements. He had the disease for 10 years and was under medication. However, with time the medication was not that effective and showed side effects; it was at that stage that we suggested DBS. Four months after the surgery, he was able to walk normally again, without support. He regained improved mobility, which prevented sudden falls and a return to normal day-to-day activities.

The procedure

DBS involves implanting electrodes deep within the brain to administer electric current and stimulate extremely precise areas, thereby alleviating the patient’s symptoms. DBS is a type of neuromodulation that involves modifying the symptoms of an illness by modulating the nervous system.

The overall procedure is five to six hours long, and usually the patient remains awake during the first half, except in special circumstances. At this stage of the surgery, electrodes are implanted using neuro-navigation, aided by a computer, which gives a 3D map of the brain and helps identify the target area and helps plan the trajectory. About 4-8 electrodes deliver electrical current to precise areas of the brain that are responsible for movement. Once it is established that the patient is benefitting from the stimulation then the final electrode is implanted to provide long-term benefits.

The other part of the procedure involves placing a neurostimulator, a pacemaker-like device, under the skin in the upper chest. A wire travels under the skin and connects to the electrodes in the brain. This part of the procedure is usually done under general anaesthesia.

Patient selection

In the case of degenerative disorders, as the disease progresses more medications are added. This may help initially but there are many side effects. DBS then becomes a necessity for these patients. Therefore, the selection of patients for DBS surgery is critical for its success. It is important to know that some Parkinson’s symptoms respond well to DBS while others do not. The decision to opt for surgery depends on a critical assessment of each person’s specific symptoms.

Usually, patients who have been diagnosed with Parkinson’s disease for five years or more, have disabling tremors and dyskinesia (involuntary movements of the face, arms, legs or trunk), have severe motor fluctuations that cannot be controlled with adjustments to medication schedules. Those who respond to medication but with reducing efficacy will make for good candidates.

Typically, DBS surgeries, including device implantation, hospital stay, and discharge would cost ₹14-15 lakh. The device itself costs ₹12-13 lakh. The advanced and new-age devices have longer battery life and MRI compatibility. The newer leads can be programmed better, to give patients more accurate as well as enhanced benefits. Overall, the device has become smaller; the patient is said to have less discomfort with it.

The outcome

After DBS surgery, patients can expect reduction in tremors, stiffness, bradykinesia (slowness of movement), dystonia (sustained or repetitive muscle twisting, spasm or cramp), and dyskinesia.

However, since patients are under a continuous influence of electrical stimulations following DBS, they must be reviewed regularly. Their symptoms could evolve due to disease progression and this needs to be addressed through constant titration of the electrical stimulations. When opting for a DBS procedure one should consider a facility with a specialist service to ensure timely intervention.

In the majority of instances, DBS is able to offload 25-50 per cent of medication and the patients have symptomatically backtracked 2-3 years. DBS also helps in terminal stages of illness where patients are bedridden, which is a great help for both patient and caregiver.

The writer is Consultant, Neurosurgery, Kokilaben Dhirubhai Ambani Hospital

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