1. Introduction

Parkinson’s is a progressive neurological syndrome affecting the initiation and performance of movement, due to the death of the brain cells responsible for producing a chemical called dopamine. This results in symptoms such as tremors (shaking), rigidity (stiffness), bradykinesia (slowness of movement), gait and balance problems.

Deep brain stimulation (DBS) is the placement of electrodes usually on both sides and rarely on one side of the brain. The electrodes are connected to a battery (IPG- implanted over chest) via an extension cable, which is surgically tunneled under the skin.

The main aim of DBS is to control the symptoms and improve quality of life but it is not a ‘cure’. Patients will continue to take medications. 

2. How can DBS help the Parkinson’s symptoms?

DBS delivers a high-frequency electrical current in the area called the STN (Subthalamic Nucleus). This current modulates misbehaving neuronal activity and decreases the symptoms of Parkinson’s disease. STN DBS help in the reduction of medication dosages. It is very important to understand that, only symptoms that are responsive to medications could improve with DBS with the exception of tremor, which can be resistant to medications but still responds to DBS. In addition, some non-motor symptoms can also improve.

3. What are the process before DBS surgery?

The initial part is a detailed pre-surgical clinical evaluation by the Functional Neuromodulation Team. Once a Patient considers undergoing DBS surgery, he/she has to get admitted in the evening before the day of the planned “Levodopa Challenge Test”.  We stop all medications on the previous night and then evaluate the patient in an “off” period in the morning and then slightly higher than the usual dose of morning medication is given to the patient. After this, we re-evaluate the patient after 30-45 minutes in the “on” period. The video recording of this testing is also done. Scores of the “on” and “off” periods are compared. If the improvement in score is acceptable according to protocol then the patient is evaluated by a Neuropsychologist for detailed cognitive and behavior assessment. Following which the patient is discharged and the appointment is booked for DBS Multidisciplinary team (MDT) meeting. In this meeting, the results of all tests done are discussed with the patient and his/her family. If the patient qualifies the candidacy criteria for surgery, all the possible pros & cons related to DBS surgery are discussed. All the possible doubts & queries of the patient and his/her family related to disease, DBS surgery, and post-surgical course are also thoroughly addressed by a team of experts. Following which final decision regarding DBS surgery is made. In case if patient and family agree to the same then presurgical investigations along with fitness are planned accordingly.

4. What happens next after the multidisciplinary clinic if you are offered surgery?

You will be given a date of admission for surgery. The morning dose of the medications with or without previous night doses is skipped according to “off” symptoms. As it is required for evaluation during surgery. MRI of the brain is also done as part of this evaluation. If the patient has severe tremors or dyskinesia (uncontrolled movements), it may be required to perform MRI under sedation or sometimes under anesthesia.

IMPORTANT: It is essential that if the patient is taking medications like aspirin, clopidogrel, warfarin, or non-steroidal anti-inflammatory drugs (NSAID): e.g. ibuprofen, naproxen, diclofenac, etc. are stopped two weeks before and until two weeks after surgery. This is mandatory to maximally avoid the risk of bleeding in the brain during surgery. If pain relief is necessary, Paracetamol is safe to use as well as Tramadol. Please discuss with the DBS team if you take any of those medications and if you take contraceptives or homeopathic over-the-counter medications.

If you are taking blood-thinning medications or anticoagulation drugs for heart disease or bleeding problems, you will need to be referred to your responsible doctors to get advice on how to stop the blood-thinning medications and the risk involved in stopping medications temporarily.

5. How long is the hospital stay for DBS surgery and What should I expect after my discharge from hospital?

The hospital stay is between 7-10 days. As soon as the patient feels well & stable and the DBS team feels so, he/she can be discharged home after testing the stimulation parameters to confirm the effectiveness of DBS. Next, the follow-up would be after 5-8 days for stitches removal. We usually start programing 2-6 weeks after the surgery. It may take several months to achieve the optimal balance of DBS settings and medication regime to achieve maximum possible benefit. Hence, patients are required to attend regular follow-ups at the hospital with the DBS team, whereby the DBS settings are fine-tuned.

6. What do I need to know about my implants after surgery?

• DBS treatment requires a lifetime commitment for regular follow-ups for review and assessment.
• Exercise and physical activity can be resumed a few weeks after surgery Sauna, steam room and sunbeds are not recommended.  Scuba diving (no greater than 33 feet) with vigilance can be done.
• Extreme/ contact sports can risk breaking or damaging the DBS hardware
• Resume work within 4-6 weeks after surgery.
• It is advisable not to drive a vehicle for 6 weeks following surgery.
• Travelling – always carry an identification card for the DBS. Do not go through airport metal detectors. If you need to travel in an airplane within 4 months after surgery, please get advice from the DBS team Do not stand near theft detectors and any object with a strong magnetic field.
• Patients will require regular battery checks and battery replacement (usually every 3-5 years for non-rechargeable DBS and 10-20 years for rechargeable DBS).
• Patients will be given a personal controller to enable them to carry out battery checks and limited adjustment of DBS settings.
• Patients should inform the DBS team if they require surgical, dental or investigative procedures so as to check hardware compatibility.
• Specific medical equipment that are contraindicated for use in patients with DBS include the following:
• Monopolar electrocautery
• Diathermy
• Bone growth stimulator
•  Lithotripsy
• Arc welding

Note: This list is not exhaustive. Please contact device booklet and manual and contact the DBS team for further advice.

• X-ray, CT scans, and mammograms are safe to use, however, patients are advised to inform the doctor or technician.
• Ultrasound is safe however the ultrasound probe should be applied directly over the implanted battery or cables because this will damage the implanted DBS battery.
• The general rule is that MRI is contraindicated in DBS implanted patients. However, depending on the model and make of the implanted DBS device, MRI can be performed under a strict protocol. Please contact the DBS team for advice.

7. What is involved in DBS surgery?

DBS surgery has got two stages. Stage-1 involves the placement of electrodes in the brain and in Stage-2 IPG (Implantable Pulse Generator) / battery is placed on the chest wall.  Usually, both stages are done one after the other on the same day but on rare occasions, Stage-2 may be delayed for a few days.

Stage-1

The first thing in the morning on the day of surgery is the fixation of the Stereotactic frame on the head. Local anesthetic will be injected at four sites on the head where pins of the frame are inserted to fix the frame. Sometimes if required sedation may be given to make you asleep to help with any sort of discomfort. Then a CT scan will be done to work out where the electrodes will need to be placed in relation to the frame. Then the patient will be shifted to OR for electrode placement.

The electrode placement will be done with the frame on and the patient in an awake state most of the time. A local anesthetic will be injected to numb the skin. Sometimes it may also be done under general anesthesia if needed. First, the skin would be opened and a small hole would be drilled (about 14mm) into the skull.  If done awake, the patient will be required to move limbs, speak or describe any unusual sensations felt. In this way, we will work with you to find the best position for electrodes. Usually, the first electrode is placed on the side opposite to the dominant hand (i.e. On the left side for the right-handed) followed by the same procedure on the opposite side. This procedure usually takes around 3-4 hours but may vary from patient to patient.

After electrode placement on both sides, another CT will be done to confirm the position of electrodes. If the position is satisfactory, the frame will be removed and the procedure for battery (IPG) placement will be done under general anesthesia. 

Stage-2

The electrodes inserted in Stage-1 are connected to internal connecting leads. They are tunneled under the skin of the neck behind the ears and connected to the battery which sits under the skin below the collar bone on the chest. The battery can be placed on either side. The final decision of the side of battery placement is of the patient according to his/her choice and comfort. This procedure takes around 1-2 hours.

 Following surgery patient will be shifted to ICU typically for a day and then if the condition permits, will be shifted back toward. The battery/IPG may be turned on 2 days after surgery. This will begin by screening the electrodes for efficacy and side effects. This process will take around 30 minutes to 1 hour. Placement of the electrode itself often improves the symptoms for a short while, in that case, the battery may not be turned on before discharge. Although final programming will start on follow-up visits.

8. What are the benefits of surgery?

DBS surgery, as mentioned earlier, significantly improves the quality of life of people with Parkinson’s disease. It extends the “on” time and reduces the duration and severity of “off” symptoms in more than 90% of patients who are properly selected.

Around 80-90% improvement is seen in tremors in most patients. Although it is never possible to predict with absolute certainty how many benefits a patient will get, the “on” – “off” assessment can give some idea about the likely benefit.

Reduction in medication doses is possible and this in-turn may improve side effects like dyskinesia.

It usually improves non-motor symptoms like pain, sadness and sleep disturbances.

9. What are the problems related to DBS surgery?

All treatments and procedures have risks & possible complications and the DBS team will talk to you about the possible risks related to DBS procedure in detail during MDT consultation before surgery.

Possible complications during “Levodopa Challenge Test”

Due to withdrawal of medications overnight, the patient may develop mild to severe withdrawal symptoms. Which may include severe “off” symptoms, perspiration, orthostatic hypotension, nausea, vomiting, worsening of generalized pain, fatigue, altered sensorium to severe complications like  NMS.

Possible risks and complications related to surgery

As with all types of surgery, DBS involves some degree of risk and chance of complications.

Complications from DBS surgery are very rare. Most complications are reversible and easy to treat and do not cause lasting morbidity.

Common risks & complications (more than 5%):

• Headaches usually improves with time
• Minor pain, bruising at the site of surgery

Uncommon risks & complications (1-5%)

• The most serious complication is surgical site and implants may become infected and need to be removed. This may require repeated surgery in the future when the infection has been cured.
• Psychological (e.g. suicidal ideation), confusion and/or memory disturbance, weight gain can occur. This may be temporary (mostly) or permanent.
• Stimulation can cause slurred speech, tingling sensations, walking difficulty, or poor balance. By programming, we aim to reduce these side effects but to get maximum improvement in Parkinson’s symptoms sometimes it may be difficult to achieve complete control of these symptoms.
• The operation may not be as successful as expected, only partially successful or the effect of stimulation may wear off with time. This may require further treatment and/or programming.

Rare risks and complications (Less than 1%)

• The Most serious complication (around 0.5%) is a risk of stroke from the procedure. It involves bleeding into the brain. Which may result in weakness on one side of the body, speech difficulty, vision impairment. The severity is related to the location and size of the bleed. Very rarely it requires surgical intervention.
• The lead, wires, or battery may move, get displaced, or try to come through the skin. This may require further surgery.
• There is the possibility of device malposition, malfunction, and lead fracture (the wire breaking). This would mean redoing the procedure, but may also mean replacing additional parts of the DBS system.
• Seizures that may require medication. This condition may be temporary or permanent.
• Fluid leakage from around the brain may occur through the wound after the operation. This may require further surgery.
• Death as a result of this procedure is very rare (0.2%).

Wound care advice:

• Before surgery, all patients are swabbed for bugs that are sensitive to antibiotics, Methicillin sensitive Staphylococcus aureus (MSSA), and for bugs that are not sensitive to antibiotics, Methicillin-resistant staphylococcus aureus (MRSA). If the swab result is positive, or the patient is unable to obtain an MSSA swab, patients are advised to strictly follow a treatment regime for 5 days prior to surgery.

• After surgery, patients are advised to avoid touching the wound area.

• Regular hand washing is advised.

• Always keep the wound area clean and dry.

• The wound dressing will be checked daily and will be replaced every 3 days.

• Patients are advised not to wash their hair until the stitches are taken out.

• Stitches are taken out 10-14 days after the surgery.