DBS Surgery with a Neurosurgeon - Things you should know

Below is an overview of Deep Brain Stimulation surgery and some talking points to have with your neurosurgeon and neurologist.  Please keep in mind that this process and the specifics can very between physicians, surgeons, and medical practices.

1. Pre-Surgical Evaluation

• Comprehensive Assessment: Not everyone with Parkinson’s disease is a candidate for DBS. Patients typically undergo a thorough evaluation by a multidisciplinary team, including neurologists, neurosurgeons, neuropsychologists, and physical therapists.
  • Neurological Exam: This evaluates the severity of motor symptoms (e.g., tremor, bradykinesia, rigidity) and the effectiveness of current medications (like levodopa). DBS is usually considered when symptoms are no longer well-controlled by medication or when medications cause severe side effects (like dyskinesias).
  • Imaging Studies: MRI or CT scans identify the exact structure of the brain and assess for any abnormalities (e.g., atrophy, lesions) that might complicate the surgery.
  • Psychiatric and Cognitive Testing: DBS is not recommended for individuals with severe psychiatric issues (like untreated depression) or significant cognitive decline because it could exacerbate these conditions.
  • Medication “On-Off” Testing: Patients may be assessed in both medicated and unmedicated states to understand how DBS might help them.

2. Surgical Preparation

• Stereotactic Frame or Robotic Guidance: A stereotactic frame is secured to the patient’s head to serve as a reference point for precise navigation. In some centers, frameless systems or robotic assistance may be used to improve accuracy.
• Brain Mapping: Imaging techniques like MRI, CT, or both are performed with the stereotactic frame in place to create a highly detailed, three-dimensional map of the brain. This map is critical for identifying the surgical targets, which are small, deep brain structures:
  • Subthalamic Nucleus (STN): Commonly targeted for reducing motor symptoms and improving movement control.
  • Globus Pallidus Interna (GPi): Often used for treating dyskinesias and motor fluctuations.
  • Thalamus (Ventral Intermediate Nucleus, or VIM): Sometimes targeted to control tremor-dominant Parkinson’s disease.

3. Electrode Placement

• Patient Awareness (Optional): Many centers perform DBS while the patient is awake for parts of the surgery. This allows the surgical team to monitor the patient’s responses to stimulation and refine electrode placement. Local anesthesia is used to minimize discomfort.
  • Microelectrode Recording (MER): A fine wire records electrical signals from individual neurons in the target area. This helps confirm the correct location of the electrodes.
  • Test Stimulation: Small electrical currents are passed through the electrodes to observe their effect on symptoms. The team may also monitor for potential side effects (e.g., muscle contractions, speech changes) to ensure proper placement.
• Securing the Electrodes: Once the optimal location is identified, the permanent electrodes are anchored in place.

4. Implanting the Pulse Generator

• General Anesthesia: After the electrodes are implanted, the patient is typically placed under general anesthesia for the second stage of the procedure.
• Pulse Generator Placement: A small device, called an implantable pulse generator (IPG), is surgically implanted under the skin, usually near the collarbone or in the abdomen.
• Connecting Wires: Thin, insulated wires (leads) connect the implanted brain electrodes to the IPG. These wires are tunneled under the skin from the scalp to the generator.

5. Post-Surgical Programming and Monitoring

• Initial Healing Period: After surgery, the patient is allowed to heal for about 2–4 weeks before the IPG is activated and programmed.
• Device Programming: A neurologist adjusts the stimulation parameters (e.g., voltage, frequency, pulse width) using a wireless device. This programming is customized to each patient’s needs and can be fine-tuned over multiple sessions.
• Medications Adjustment: DBS typically reduces the need for Parkinson’s medications, but does not eliminate them. A neurologist works to optimize the balance of stimulation and medication to minimize side effects and improve function.

6. Long-Term Management

• Follow-Up Visits: Regular follow-ups are essential to monitor symptom control, address side effects, and adjust stimulation settings.
• Battery Maintenance: The IPG battery life depends on the stimulation settings and type of generator. Rechargeable IPGs can last 10–15 years, while non-rechargeable ones may need replacement every 3–5 years.
• Therapeutic Effects: DBS is most effective for motor symptoms such as tremor, rigidity, bradykinesia, and dyskinesias caused by medications. It generally has limited impact on non-motor symptoms (e.g., sleep disturbances, cognitive decline).

Potential Risks and Side Effects

• Surgical Risks: Include infection, bleeding, or stroke, though these are rare in experienced centers.
• Stimulation Side Effects: Depending on the location and settings, DBS can sometimes cause speech problems, balance issues, or mood changes.
• Psychosocial Impact: Patients and families may need support to adapt to changes in symptoms, medication regimens, and lifestyle.

Benefits of DBS

• Improved Motor Function: Reduces tremors, rigidity, and movement fluctuations.
• Lower Medication Dependency: Decreases reliance on Parkinson’s medications, reducing side effects like dyskinesias.
• Reversible and Adjustable: DBS settings can be modified or turned off if needed, unlike other surgical interventions (e.g., lesioning procedures).

Final Thoughts
DBS is a life-changing intervention for many Parkinson’s patients, offering substantial improvement in motor symptoms and quality of life. However, it requires careful candidate selection, skilled surgical teams, and long-term management to achieve the best outcomes.  Please have in-depth discussions with your neurologist and neurosurgeon about this process.