Functional neurosurgery is a specialized field within neurosurgery that focuses on treating neurological conditions by modulating or altering the function of specific areas of the brain, spinal cord, or peripheral nerves. Unlike traditional neurosurgery, which primarily focuses on removing tumors or repairing structural abnormalities, functional neurosurgery aims to address disorders of the nervous system through interventions that affect neural circuitry and brain function.

Functional neurosurgery encompasses a variety of techniques and procedures, including:

• Deep brain stimulation (DBS): This involves implanting electrodes into specific regions of the brain and connecting them to a pacemaker-like device called a neurostimulator. The neurostimulator delivers electrical impulses to the brain, modulating abnormal neural activity and alleviating symptoms associated with movement disorders such as Parkinson's disease, essential tremor, and dystonia.
• Neuromodulation: This technique involves using electrical or magnetic stimulation to modulate the activity of nerves or neural circuits, either directly or through implanted devices. Neuromodulation techniques may be used to treat chronic pain, epilepsy, depression, and other neurological disorders.
• Stereotactic radiosurgery: This non-invasive technique delivers precisely targeted radiation to specific areas of the brain, spinal cord, or peripheral nerves, typically using gamma knife or cyberknife technology. Stereotactic radiosurgery is often used to treat tumors, vascular malformations, and functional disorders such as trigeminal neuralgia.
• Intrathecal drug delivery: This involves implanting a pump into the abdomen that delivers medication directly into the spinal fluid, bypassing the blood-brain barrier. Intrathecal drug delivery is used to treat chronic pain, spasticity, and other neurological conditions that are not adequately controlled with oral medications.
• Neuroablative procedures: These involve selectively destroying or lesioning specific areas of the brain or peripheral nerves to alleviate symptoms of movement disorders, chronic pain, or psychiatric conditions. Neuroablative procedures may be performed using various techniques, including radiofrequency ablation, gamma knife surgery, and focused ultrasound.

Functional neurosurgery requires a multidisciplinary approach involving neurosurgeons, neurologists, psychiatrists, neuropsychologists, and other specialists. Patient selection, preoperative evaluation, and postoperative management are critical aspects of the treatment process to ensure optimal outcomes and patient satisfaction.