Functional and Stereotactic Neurosurgery
Core concepts
Know the targets and indications for deep brain stimulation (DBS) in Parkinson disease, essential tremor, and dystonia, and the principles of patient selection. Understand stereotactic frames and frameless navigation, the anatomy of the basal ganglia and thalamic nuclei, and the complications of DBS (hemorrhage, infection, lead migration). Cover epilepsy surgery: seizure semiology, presurgical evaluation, and resective versus palliative procedures. Also know the principles of pain surgery, including spinal cord stimulation and ablative procedures, and the role of stereotactic biopsy.
Traps
- Assuming DBS is appropriate for all Parkinson patients; selection depends on medication response, cognition, and expectations.
- Confusing the subthalamic nucleus (motor symptoms) with the ventral intermediate nucleus of the thalamus (tremor).
- Forgetting that stereotactic biopsy carries a hemorrhage risk and may be nondiagnostic.
- Missing that epilepsy surgery requires a clear seizure focus and presurgical evaluation.
Worked example / rule of thumb
A patient with Parkinson disease and motor fluctuations despite optimal medication, with intact cognition, is a candidate for DBS, commonly targeting the subthalamic nucleus. Rule of thumb: DBS treats symptoms, not the disease, and the best predictor of response is prior response to levodopa.