Track 36: Stereotactic and Functional Neurosurgery

Stereotactic and Functional Neurosurgery is a specialized field of neurosurgery that focuses on precise, targeted interventions in the brain to treat various neurological disorders, often related to movement, pain, and psychiatric conditions. This field combines advanced imaging techniques (stereotactic) and the functional understanding of the brain (functional neurosurgery) to perform highly focused, minimally invasive surgeries with the goal of improving patients' quality of life.

Key Concepts in Stereotactic and Functional Neurosurgery

1. Stereotactic Neurosurgery

Stereotactic refers to a method that uses 3D coordinates in space to locate precise areas in the brain. This technique allows surgeons to target specific regions of the brain with high accuracy, minimizing damage to surrounding healthy tissue.

• Stereotactic Frame: A rigid frame attached to the patient’s head during surgery to guide the surgeon’s instruments precisely to the targeted area based on MRI or CT imaging.
• Image Guidance: Imaging technologies like MRI, CT scans, and functional MRI (fMRI) provide real-time data to guide the surgeon during the procedure.
• Computer-Assisted Navigation: Surgeons use computer systems to help plan and navigate the surgery, making it more precise and reducing human error.

2. Functional Neurosurgery

Functional neurosurgery focuses on modifying brain circuits to treat neurological disorders that affect movement, mood, or cognition. It typically involves the implantation of devices or targeted brain lesions to alter the brain's activity, improving symptoms of diseases.

• Functional Targets: These may include regions of the brain involved in motor control (such as the basal ganglia), pain regulation, mood, and cognition.

Common Disorders Treated with Stereotactic and Functional Neurosurgery

1. Movement Disorders

Movement disorders involve abnormalities in motor function, often caused by disruptions in brain circuits. Stereotactic and functional neurosurgery is particularly effective for treating conditions like:

• Parkinson's Disease: A progressive neurodegenerative disorder that affects movement, causing tremors, rigidity, bradykinesia (slowness of movement), and postural instability.

  • Deep Brain Stimulation (DBS): The most common procedure for Parkinson's disease, where electrodes are implanted in specific areas of the brain (usually the subthalamic nucleus or globus pallidus internus) to deliver electrical impulses that regulate abnormal brain activity.
  • Pallidotomy or Thalamotomy: These procedures involve making small lesions in specific brain areas to reduce symptoms of tremors and rigidity in Parkinson’s disease.

• Essential Tremor: A neurological condition that causes uncontrollable shaking, especially in the hands. DBS can be used to control tremors by targeting the thalamus, a brain structure involved in movement.

• Dystonia: A movement disorder that causes sustained muscle contractions and abnormal postures. DBS is commonly used for generalized dystonia, with targets such as the globus pallidus or thalamus.

• Tremor and Hyperkinetic Disorders: These include Huntington's disease and tourette syndrome, where DBS or lesioning can help control involuntary movements.

2. Chronic Pain

Stereotactic and functional neurosurgery can be used to treat certain types of chronic pain by targeting specific regions of the brain or spinal cord involved in pain processing.

• Pain Modulation via DBS: DBS can be applied to the ventral posterior nucleus of the thalamus or the periventricular grey matter to alleviate chronic pain, particularly in conditions like trigeminal neuralgia or post-stroke pain.

• Dorsal Column Stimulation: In some cases of intractable pain, particularly in the limbs or back, spinal cord stimulation (SCS) or dorsal root entry zone (DREZ) lesions can be performed to modify pain pathways.

3. Psychiatric Disorders

Functional neurosurgery is also used to treat psychiatric conditions when other treatments (such as medication or therapy) have not been effective.

• Obsessive-Compulsive Disorder (OCD): For severe cases of OCD, DBS or targeted lesions in brain regions like the cingulate gyrus or orbitofrontal cortex can provide significant relief from symptoms.

• Major Depression: In cases of treatment-resistant depression, DBS may be used to stimulate areas of the brain such as the subgenual cingulate or prefrontal cortex, which are involved in mood regulation.

4. Epilepsy

Certain forms of epilepsy that do not respond to medications can benefit from stereotactic and functional neurosurgery.

• DBS: It is used for refractory epilepsy to help control seizure activity by targeting areas in the brain that are responsible for initiating seizures, such as the thalamus or cortex.

• Stereotactic Radiosurgery (SRS): High-dose radiation is precisely delivered to specific brain regions to treat epileptic foci, minimizing damage to surrounding tissue. This is typically used when surgical resection is not feasible.