Cerebrovascular Neurosurgery
Expect a ruptured aneurysm scenario, a decision between clipping and coiling, a vasospasm question and an acute stroke thrombolysis decision.
Aneurysmal subarachnoid haemorrhage
- Grade with WFNS or Hunt and Hess; modified Fisher grade on CT predicts vasospasm.
- Rebleeding risk is highest in the first 24 hours, so secure the aneurysm early. ISAT and BRAT support endovascular coiling for many anterior circulation aneurysms, while clipping is favoured for middle cerebral bifurcation aneurysms, large haematomas and unfavourable neck anatomy.
- Nimodipine 60 mg every 4 hours for 21 days improves outcome. Do not stop it for a modest blood pressure fall; reduce the dose or manage pressure otherwise.
- Vasospasm peaks days 3 to 14. Transcranial Doppler mean MCA velocity above 120 cm/s suggests it. Maintain euvolaemia, not triple-H therapy; use endovascular angioplasty or intra-arterial vasodilator for symptomatic deficit.
- Hydrocephalus in poor-grade patients with dilated ventricles is treated with an external drain.
AVMs and cavernomas
- Spetzler-Martin score: size under 3 cm is 1 point, 3 to 6 cm is 2, over 6 cm is 3; eloquence 1; deep venous drainage 1.
- Annual AVM haemorrhage risk is roughly 1 to 3 percent, higher after a previous bleed, with deep location and with associated aneurysms.
- ARUBA favoured medical management for unruptured AVMs at short follow-up, but it has been criticised and does not govern ruptured AVMs in young patients.
- Cavernoma: popcorn lesion with a complete haemosiderin ring on GRE or SWI; resect when recurrently symptomatic and accessible.
Ischaemic stroke and intracerebral haemorrhage
- Intravenous thrombolysis within 4.5 hours if no contraindication, with blood pressure below 185/110.
- Thrombectomy for anterior circulation occlusion within 6 hours, and in selected patients with penumbra up to 24 hours.
- Malignant MCA infarction: decompressive hemicraniectomy within 48 hours, clearly beneficial under 60 and reasonable in selected older patients.
- Intracerebral haemorrhage: lower systolic pressure to about 140, reverse anticoagulation, and evacuate cerebellar haematoma over 3 cm or with brainstem compression.
Worked example
A 55-year-old with WFNS grade 2, a 7 mm anterior communicating aneurysm and dilated ventricles: secure the aneurysm within 72 hours, place an EVD for the hydrocephalus, start nimodipine and keep the patient euvolaemic.
Traps
- Withholding nimodipine because of hypotension.
- Using triple-H therapy instead of euvolaemia.
- Delaying aneurysm treatment to wait for vasospasm.