What is Deep Brain Stimulation? 

Source: By Dr Col Anil Kakkar: The Indian Express

What Adolf Hitler, Mao Zeadong, George HW Bush Senior, Vladimir Putin, Pope John Paul II, Muhammed Ali, Rev. Jesse Jackson, Davis Phinney and Michael J Fox have in common — just like more than 10 million people in the world — is Parkinson’s disease (PD). The incidence of PD is also rising across India like other parts of the world with increasing life expectancy, which has nearly doubled from the beginning to the end of last century. The prevalence of PD is 8 percent of the global burden, making it the second most common ageing-related disorder (after Alzheimer’s). Every year, globally, more than 50,000 people are told they have Parkinson’s disease.

It is important to understand the disease, but more important to translate this understanding to better therapy, which may not cure/stop the progression, but give better quality living. That is deep brain stimulation (DBS) — a surgical therapy used for the treatment of PD. The time to consider DBS is when the quality of life is no longer acceptable on optimal medical therapy as administered by a movement disorder specialist.

DBS surgery implants a device that sends electrical signals to brain areas resulting in blockage of some of the messages that cause the movement symptoms, improving communication between brain cells to reduce symptoms of PD. Electrodes are placed deep in the brain and are connected to a stimulator device. Similar to a pacemaker, a neurostimulator uses electric pulses to regulate brain activity.

Modern DBS was developed in France in 1991 by professor of neurosurgery Dr Alim-Louis Benabid. With advances in technology and surgical practices, the therapy has continued to improve and DBS is now a standardised procedure in more than 1,200 hospitals around the world in 70+ countries. It was first approved by FDA in the USA in 2003 only for advanced cases of PD initially, and later in 2011, for all cases including dystonia, essential tremors, epilepsy and OCD, and is now considered a quite a safe and effective treatment for selected patients with PD by a multidisciplinary team.

More than 1, 75,000 people have had DBS therapy in the last 19 years in the world, with a success rate of over 97 per cent. In India, about 500 DBS surgeries occur annually. So far, this facility is available only in metros like Mumbai, Delhi-NCR, Bengaluru, Hyderabad, Chennai and Kolkata.

Three types of DBS systems are currently available. Each system has its own advantage. The electrical stimulation is adjustable and can be easily changed. All three companies claim the DBS system is also MRI compatible, and it works 24 hours a day.

On the day of surgery — 16 June 2021 — at Gurugram Artemis Hospital, after a nice hot water bath using the germicidal solution, I was wheeled into the CT room early in the morning and within a few minutes; a team of surgeons checked the size of the skull cage. Dr Aditya Gupta, the chief of neurosurgery, started numbing my skull by administering local anaesthetic using thin needles. After the cage was firmly screwed and secured into my skull, l was put on a CT scan machine. Dr Gupta explained it was done to help surgeons know where exactly to place the electrodes in my brain.

Then I was wheeled into the OT. In the pre-op room, I was explained by a team of anaesthesiologists why, during the procedure, I had to be 100 per cent alert and awake — I had to cooperate and bear some discomfort and pain. If you are sedated, it could change the firing patterns of the cells in your brain and make the brain mapping more difficult.

Soon, I found myself in the main OT. Different teams worked on different projects. Anaesthetic team starting arterial line, putting Foley’s catheter, relieving some of my pain with IV injections, paracetamol and injecting pre-operative antibiotics. Surgical side positioned and fixed the head so that surgeons could comfortably operate, along with the proper preparation of operative site (removal of hair) and cleaning of the skin with different antiseptic lotions; sterile towels and sheets to cover the exposed area to minimise the possible risk of infection. I could see a ray of light, a hope to improve the quality of my life to not be dependent on another.

Now, since the brain does not have any pain receptors, local anaesthetics are given over the scalp, where the skin is cut and holes are drilled into the skull. I soon realised, after the bone chip was removed, that they had started cutting my dura (the outermost, toughest and most fibrous layer of meninges surrounding the brain and spinal cord) to expose my brain, so electrodes can be inserted into the target area: subthalamic nucleus (STN).

I looked at the wall clock — which I thought was not moving — and realised it was one of those days when every minute would feel like an hour.

Finally, Dr Aditya Gupta asked the technical staff about the exact positioning of the electrodes as per their calculations, after fusion of images and after inserting them and re-checking. After this, everybody waited for the neurologist to arrive and clinically correlate and finalise the correct electrode to be capped. Soon, Dr Sumit Singh, head of the neurological team arrived and began to check the movements of my right hand and foot, asking me to repeat reverse-counting; after he was satisfied, he finalised the electrodes on the left side and said, “Yes, we are good to go to the other side”, referring to my brain. The same things were repeated on another side including the wait for a neurologist.

Then, there was another CT scan on the OT table to recheck the positioning of the electrodes, and to rule out any possible intracranial haemorrhage. The rest of the surgery was a mystery (creating a subcutaneous tunnel and placing the device under the left collar bone). I was luckily under general anaesthesia, for approximately 30-40 minutes. When I reopened my eyes, I found myself in neuro-ICU with my dear wife and son standing next to me.

It was an amazing experience. Not only was I able to hear everything in the OT, but the feeling of pain and the sensation of the skull being opened and electrodes inserted was quite a unique experience.

I am glad to return to my favourite activities and experience the joy of doing the simplest things in life once again: playing golf and driving. The biggest thing for me is having my smile back. I am taking almost 1/10th of the medicines I was previously taking. My tremors, stiffness are non-existent, and routine daily activities are easier, like bathing, getting ready, drinking and writing. I feel better emotionally, with less physical discomfort and less embarrassment in public.