Functional and Epilepsy Neurosurgery (Movement Disorders, Pain, Epilepsy, Radiosurgery)
What the candidate must own
Know the basal ganglia circuitry and the targets for deep brain stimulation: subthalamic nucleus and globus pallidus internus for Parkinson disease and dystonia, and ventral intermediate thalamus for tremor. Understand patient selection - levodopa responsiveness, cognitive status, and age - and the complications of DBS (infection, hardware failure, stimulation-induced dysarthria, and mood changes). For epilepsy, know the presurgical evaluation: semiology, video-EEG, MRI with epilepsy protocol, and the role of invasive monitoring; and the resective procedures (temporal lobectomy, lesionectomy, hemispherotomy) and palliative options (vagus nerve stimulation, responsive neurostimulation). For pain, know the indications for spinal cord stimulation, dorsal root entry zone lesioning, and trigeminal rhizotomy. Understand stereotactic radiosurgery principles for functional targets.
Traps that appear in questions
- Offering DBS to a patient with significant cognitive impairment or atypical parkinsonism.
- Assuming all epilepsy surgery is temporal - extratemporal and lesional cases require tailored approaches.
- Forgetting that vagus nerve stimulation is palliative, not curative.
- Confusing radiosurgery (single high-dose, functional targets) with fractionated radiotherapy.
Rule of thumb
For functional surgery, selection beats technique: the best outcome comes from the right patient, not the most advanced target. Worked example: a 60-year-old with Parkinson disease, motor fluctuations, preserved cognition, and robust levodopa response is a candidate for bilateral subthalamic DBS; a patient with early cognitive decline or atypical features is not.