Functional and Stereotactic Neurosurgery
What you must own
Understand stereotactic principles: frame-based versus frameless navigation, stereotactic coordinates, and the role of imaging in targeting. Know the basal ganglia and thalamic anatomy relevant to functional targets (subthalamic nucleus, globus pallidus internus, ventral intermediate thalamus).
Movement disorders: deep brain stimulation for Parkinson disease (STN or GPi), essential tremor (VIM), and dystonia (GPi). Understand the difference between ablative procedures and neuromodulation. Know the complications of DBS (infection, lead migration, haemorrhage, stimulator-related effects).
Epilepsy surgery: the concept of the epileptogenic zone, presurgical evaluation (video-EEG, MRI, PET, SPECT, intracranial monitoring), and procedures (temporal lobectomy, lesionectomy, vagus nerve stimulation, corpus callosotomy for drop attacks).
Pain and spasticity: spinal cord stimulation, intrathecal baclofen, and dorsal rhizotomy. Psychiatric and emerging indications (e.g. obsessive-compulsive disorder) are recognised but not first-line.
Traps
Questions test the correct DBS target for a given condition (STN/GPi for Parkinson, VIM for tremor, GPi for dystonia). Another trap: confusing vagus nerve stimulation (palliative, not curative) with resective epilepsy surgery.
Rule of thumb
Match the target to the disorder: STN or GPi for Parkinson, VIM for essential tremor, GPi for dystonia.
Worked example
A patient with medically refractory essential tremor is considered for DBS. The correct target is the ventral intermediate nucleus of the thalamus, not the STN, which is used for Parkinson disease.