Types of Functional Neurosurgery

Functional neurosurgery is a specialized branch of neurosurgery focused on treating disorders related to how the brain, spinal cord, and nerves function—rather than structural problems like tumours or injuries. It primarily targets conditions such as epilepsy, Parkinson’s disease, chronic pain, dystonia, tremors, and psychiatric disorders through surgical interventions that restore or improve neurological functions.

Over the last two decades, advances in imaging, mapping technologies, and neurostimulator devices have made functional neurosurgery more precise and effective. With an increasing number of patients seeking alternatives when medications fail, these procedures have become crucial in managing chronic neurological conditions.

Why Functional Neurosurgery?

Medication-Resistant Conditions: Many neurological disorders, like epilepsy or movement disorders, don’t respond well to medication long term.

1. Targeted Intervention: Instead of treating symptoms, functional neurosurgery modifies dysfunctional neural circuits directly.
2. Improved Quality of Life: Procedures like Deep Brain Stimulation (DBS) can dramatically reduce tremors and improve motor control in Parkinson’s disease.
3. Minimally Invasive Options: Many surgeries are now performed using minimally invasive methods, reducing recovery time and risks.

Major Types of Functional Neurosurgery

Functional neurosurgery encompasses several highly specialized procedures. Below are the most commonly performed types, with their indications and benefits:
1. Deep Brain Stimulation (DBS)

What it is: DBS involves implanting electrodes into specific areas of the brain and connecting them to a pulse generator (like a pacemaker) injected under the skin. It sends electrical impulses to modulate abnormal brain activity.
Conditions Treated:

• Parkinson’s disease
• Essential tremor
• Dystonia
• Tourette syndrome
• OCD (Obsessive Compulsive Disorder)

Benefits:

• Reduces motor symptoms in Parkinson’s by up to 60–70%
• Adjustable and reversible
• Fewer side effects compared to long-term medication use

2. Epilepsy Surgery

What it is: When epilepsy is resistant to medication, surgery can remove or isolate the area of the brain where seizures originate.
Types of Procedures:

• Temporal Lobectomy: Removal of part of the temporal lobe, most effective for temporal lobe epilepsy.
• Lesionectomy: Removal of abnormal tissue (tumour, scar).
• Corpus Callosotomy: Severing connections between brain hemispheres to prevent the spread of seizures.
• Vagus Nerve Stimulation (VNS): A device implanted in the chest sends signals to calm electrical brain activity.

Benefits:

• Up to 70–80% seizure reduction
• Improved cognitive function and quality of life
• Reduced dependency on antiepileptic drugs

3. Pain Modulation Surgeries

What it is: Chronic pain that doesn’t respond to medications can be treated surgically by modifying pain pathways in the nervous system.
Common Techniques:

• Spinal Cord Stimulation (SCS): Implantation of electrodes along the spine to interfere with pain signals.
• Motor Cortex Stimulation (MCS): Used for central pain syndromes.
• Dorsal Root Entry Zone (DREZ) Lesioning: Used for brachial plexus avulsion pain.
• Microvascular Decompression: Effective in treating trigeminal neuralgia.

Benefits:

• Long-term pain relief without opioids
• Improves functional ability and mobility
• Enhances mental health by reducing pain-induced depression

4. Psychiatric Neurosurgery

• What it is: For treatment-resistant psychiatric disorders, surgical interventions can target brain circuits involved in mood, emotion, and behaviour.
  Types of Procedures:
• Anterior Cingulotomy: Disrupts the circuit involved in depression and anxiety.
• Subcaudate Tractotomy & Limbic Leucotomy
• DBS for OCD and Depression

Conditions Treated:

• Major Depressive Disorder
• Obsessive-Compulsive Disorder (OCD)
• Severe Anxiety Disorders

Benefits:

• Considered when all other treatments fail
• Can provide substantial improvement in mood and behaviour
• Highly targeted with fewer cognitive side effects than early psychosurgeries

5. Movement Disorders Surgery (Beyond DBS)

Though DBS is the gold standard, other lesioning procedures are still used in select cases:

• Pallidotomy: Destroys part of the globus pallidus to reduce involuntary movements.
• Thalamotomy: Destroys part of the thalamus to control tremors.
• Focused Ultrasound (FUS): A non-invasive option that uses sound waves to destroy targeted brain tissue.

Benefits:

• Useful when DBS is not an option
• Effective in unilateral symptom control
• Quick results without implanted hardware

Advanced Techniques in Functional Neurosurgery

1. Stereotactic Navigation: Ensures pinpoint accuracy during surgery.
2. Intraoperative MRI: Real-time imaging during surgery for precise targeting.
3. Robotics and AI Integration: Used to enhance precision and reduce human error.

These technologies have revolutionized patient outcomes, making surgeries safer and more effective.

Risks and Considerations

As with any surgery, functional neurosurgery carries certain risks:

• Infection
• Bleeding
• Neurological deficits
• Hardware complications (in DBS or VNS)

However, in experienced hands and with appropriate patient selection, the benefits significantly outweigh the risks.

Conclusion

Functional neurosurgery has emerged as a life-changing option for patients living with chronic neurological and psychiatric disorders. From controlling tremors and seizures to managing depression and chronic pain, these procedures provide hope where medications fall short. With continued advancements in imaging, robotics, and neurostimulation technologies, the future of functional neurosurgery looks increasingly promising.
Whether you’re a patient seeking options or a healthcare provider researching therapies, understanding the types and benefits of functional neurosurgery can help guide better treatment decisions.