Deep Brain Stimulation

Deep brain stimulation (DBS) is a neurosurgery wherein electrodes are inserted in certain areas of a person's brain to alter abnormal electrical activity associated with certain neurological movement disorders.

Movement disorders (such as Tourette syndrome or Parkinson’s disease) occur due to abnormal activity in certain parts of the brain that control movement. These disorders increase body movements or decrease them, resulting in a variety of symptoms, namely, stiffened muscles, shaking tremors, or repetitive movements or sounds. These conditions are genetically inherited or caused due to brain infections, injury, autoimmune diseases, or medications.

Similar to movement disorders, other neurological conditions also arise from irregular electrical signals in the brain.

A deep brain stimulation system is placed in the skull in such conditions to interrupt these electrical signals and prevent the resulting symptoms.

The DBS system consists of the following parts:

• Leads: Insulated wires that end in electrodes placed in the targeted areas of the brain responsible for symptoms.
• Anchors: It fixes the lead to the skull.
• Implantable pulse generator: A pacemaker-like device placed below the skin of the chest, usually near the collarbone.
• Extension leads: These are thin, insulated wires that may be added to connect the device to the leads.
• Hand-held programmer device: A device to switch on/off the main device and to adjust the electric signals sent by the pulse generator

On activation, the pulse generator sends continuous electrical signals to the electrodes that modify the abnormal activity in the target regions of the brain (the one that is causing symptoms) and provide relief from the symptoms of the condition.

Deep brain stimulation does not cure the condition; it increases your ability to manage it and decreases your dependency on medications.

This surgery is recommended in individuals with the following conditions:

• Parkinson’s disease: Symptoms of the disease are:
  • Unsteady walk and balance
  • Tremors in arms, hands, foot, or jaw
  • Slowing down of movements
  • Inability to move freely
  • A hunched over posture
• Dystonia: Common symptoms of dystonia include:
  • Foot cramps
  • Sloppy handwriting
  • Speech difficulties
  • Tremors
  • Extended periods of stress or fatigue
• Essential tremor: The symptoms of essential tremor are:
  • Nodding head
  • Shaking voice
  • Tremors that decrease after rest
  • Uncontrollable shaking for brief periods
• Obsessive-compulsive disorder (OCD): OCD symptoms involve:
  • Fear of contamination by germs or dirt
  • Need to arrange things in symmetry or order
  • Fear of making mistakes or thinking sinful thoughts
  • A constant need for reassurance
• Epilepsy: The symptoms may vary based on the type of epilepsy. These include:
  • Rhythmic/jerking movement of head or limbs
  • Fluttering eyelids
  • Brief loss of consciousness
  • Rigidity and stiffness of the whole body
  • Lip smacking

Individuals with any of the above condition are considered for the surgery if medicines do not provide adequate relief from symptoms or if the medications cause intolerable side effects, thus reducing the overall quality of life. Deep brain stimulation may also be performed to treat conditions like chronic pain, major depression, or Tourette syndrome.

The contraindications to this surgery include:

• Dementia
• Dominant levodopa-resistant motor symptoms such as postural instability, freezing of gait, and dysphagia
• Active (uncontrolled) psychiatric disorders
• Abnormalities observed in magnetic resonance imaging or MRI

Before the surgery, your surgeon will ask you to undergo several medical and imaging tests to ensure that you would benefit from DBS. The tests include:

• Blood tests
• Evaluation of your video recordings doing several activities when you are on medication and when you are not
• Neuropsychological assessment to study your mood, memory, and thought process
• MRI

Also, the surgeon will give you certain instructions to prepare for the surgery. During the discussion, he/she will ask you to:

• Share a list of medicines that you take, including herbs and over-the-counter medications.
• Discontinue blood-thinning medicines (warfarin, aspirin, ibuprofen, etc.) a week before the surgery.
• Arrange for a friend, family member or a responsible adult to drive you home after the procedure.
• Stop smoking.
• Fast from midnight prior to the surgery.
• Sign an approval form if you agree to the surgery.

The surgery is performed in two stages to place the whole DBS system; either on the same day or three to six weeks apart. After you are admitted to the hospital, the hospital staff will provide you with a hospital gown and compression stockings. The stockings help to prevent the formation of blood clots in legs.

The first stage of the surgery comprises:

• An anaesthetist will give you local anaesthesia (medicine to keep you pain-free but awake) at four sites on your head for placement of a stereotactic frame that will be fixed on your head with screws.
• You may also be given a sedative to help you relax during the procedure.
• Thereafter, you will undergo an MRI scan before leaving for the operating room.
• Someone from the medical team will shave a small portion of hair from your scalp (which is to be operated on).
• You will again be given local anaesthesia at the shaved side.
• The surgeon will drill a small hole on one side of your skull.
• Thereafter, he/she will identify the areas in your brain to insert an electrode. For this, the surgeon will pass electrical impulses into your brain and ask you to move your limbs or describe any images you see or any unpleasant sensations that occur. 
• Once the correct position is found, the surgeon will secure the electrode inside your brain using a small metal plate and screws.
• The surgery will be repeated on the other side of the skull if needed.
• You will undergo another brain scan after the insertion of the electrodes.
• If the location of the electrodes is accurate, the surgeon will remove the frame and screws from your head.
• The surgeon will close your skull with a plastic cap and suture up the incision.

The procedure takes around two hours. When you wake up, you will find one or two wires coming out of your skin. These are connecting wires that will be attached to an external device to test brain stimulation. The location of the wires will depend on the position of the implanted electrodes. The testing will be conducted for about a week. If the surgeon finds the stimulation successful in reducing the symptoms, stage 2 of the surgery will then be planned. If the stimulation is unsuccessful, the wires will be removed by another procedure.

Stage 2 of the procedure, which takes about two to three hours, is done as follows:

• You will be given general anaesthesia to make you fall asleep.
• Depending on the position of insertion of the pulse generator, the surgeon will make a small incision on your skin. The generator will be implanted under your skin either below your collarbone or abdominal area.
• The surgeon will pass the extension lead beneath the skin of your head, neck, and shoulder and attach it to the generator. They will be connected to the electrodes on the other end via the connecting wires.
• Once the connection is made, he/she will close the incisions.

You can expect the following after either of the two stages of surgery:

• The hospital staff will move you to the recovery room.
• You will have an intravenous catheter (tube) inserted in your arm to supply essential fluids and medications.
• You may also have an oxygen mask to help you breathe.
• In the hospital room, your vital signs will be regularly monitored.
• A nurse will give you pain medications if you experience any pain.
• You will also be given antibiotics to prevent infections.
• You will be advised to change your position in bed every two to three hours to avoid extended pressure on any part of your body.
• The hospital staff will help you to get out of bed if you are in a stable condition. This will help promote recovery.
• After undergoing the second stage of the surgery, you may feel sleepy, sick, and nauseous.
• You will have bruising and swelling on your head after the surgery. It will resolve within a few months.
• The duration of hospital stay varies from person to person and will depend on your speed of recovery.

Implantation of the electrode will help to control your symptoms for a few days. Hence, the pulse generator will not be switched on until your symptoms return.

You will need to take the following care at home:

• Continue taking your medications as usual.
• The surgeon will advise you to avoid taking a shower until your incisions heal.
• You cannot drive for about six weeks after the surgery.
• Avoid operating radar or high-voltage machinery such as a smelting furnace, electric arc welder, or television transmitter.
• Do not take physiotherapy that uses heat.
• Inform security officials about the presence of the pulse generator if you need to go through an airport detector. Although the sensors do not affect the functioning of the device, you should instruct the officials to not hold the hand-held detectors over the pulse generator for more than a few seconds as the magnets in the detector may affect the functioning of the device. 
• Before undergoing any surgeries in the future, inform the surgeon about your pulse generator.
• Avoid indulging in sports and other physical activities that can injure the area near the implanted pulse generator since it can affect the functioning of the device.
• Consult your doctor before undergoing an MRI scan.
• You can undergo diagnostic ultrasound scans; however, ultrasound treatments are not permitted.

This surgery provides the following benefits:

• Alleviates symptoms of movement and other neurological disorders
• Reduces your dependency on medications, thereby lowering the side effects associated with them.

When to see the doctor?

Contact the surgeon if you experience any of the following after the surgery:

• Fever
• Headache
• Nausea and vomiting
• Muscle weakness
• Itching
• Vision problems
• Speech difficulties
• Numbness on one half of the body
• Redness and swelling on the operated area

The surgery carries the following risks:

• Blood clots in the brain, resulting in permanent disability
• Infection of the leads
• Allergic reaction to the implants
• Dizziness
• Weakening of voice
• Loss of balance
• Leakage of fluids from the brain
• Short-term confusion
• Erosion of the wires through the skin
• Shock-like sensation
• Difficulty concentrating
• Breaking of the device or wire inside the body, which will need another surgery to replace the broken parts

Your follow-up appointment will be scheduled 10 to 14 days after the surgery to remove the stitches. You will need to revisit the hospital after a few weeks to activate the pulse generator and program it for optimal stimulation.

Disclaimer: The above information is provided purely from an educational point of view and is in no way a substitute for medical advice by a qualified doctor.