[ Neurosurgery ] SAH 5

Giant berry aneurysm – treatment

Direct surgical clipping (ideal if feasible), or clipping plus bypass.

Vascular malformations (McCormick) – examples

AVM, cavernous angioma, and venous angioma.

AVM – definition

Abnormal direct fistulous connections between arteries and veins without a capillary bed.

AVM – origin and presentation

Mostly congenital, most become symptomatic later in life, and 90% are cerebral.

AVM – epidemiology

Slight male predominance, most common in the 2nd to 4th decades.

AVM – parts

Feeding artery, nidus, and draining vein.

AVM – pathophysiology

High-flow, low-resistance shunt with steal phenomenon (hypoperfusion of the abnormal surrounding brain).

AVM – most common presentation

Intracranial hemorrhage (50%), mainly intracerebral, mostly from small lesions, peak age 15 to 20.

AVM – 2nd most common presentation

Seizures, more with larger AVMs.

AVM – other features

Headache and bruit.

AVM – initial test

CT or CTA, which may show calcification flecks in the nidus but gives poor angioarchitecture.

CT and CTA in AVM – uses

Non-contrast CT for hemorrhage, CTA identifies feeding arteries, nidus, and draining veins.

MRI in AVM – findings

Flow voids on T1 and T2, with size and site.

AVM – gold standard investigation

DSA, best for angioarchitecture.

Spetzler-Martin grading – purpose

Estimates the surgical risk of an AVM.

Spetzler-Martin – components

Size (0 to 3 cm is 1, 3.1 to 6 cm is 2, over 6 cm is 3), eloquent location (1), and deep venous drainage (1).

AVM – treatment of choice

Surgical resection, indicated for grades I to III.

AVM – embolization and radiosurgery

Mostly adjunct to surgery, or used alone in high grades.

AVM – preoperative drug

Beta-blocker (propranolol).

Spetzler-Martin – approach by grade

Low grades (I and II) surgery is gold standard, grade III is most difficult (multimodal, mostly surgery), high grades (IV and V) no surgery