Endovascular Treatment of Non-Ruptured Cerebral Aneurysm

Treatment Indication Framework

The American College of Neurosurgery recommends treatment for aneurysms ≥5mm in patients under 60 years of age, and symptomatic unruptured aneurysms should be treated with rare exceptions 1, 2
Aneurysms <5mm should be managed conservatively in virtually all cases, while aneurysms 5-10mm should be seriously considered for treatment in patients younger than 60 years of age 1, 2
The yearly rupture risk for aneurysms 7-10mm in diameter is approximately 1%, making prophylactic treatment beneficial for reducing long-term morbidity and mortality 1, 2

Digital subtraction angiography remains the gold standard for definitively characterizing aneurysm neck morphology, relationship to parent vessels, and precise anatomic location 2
Endovascular treatment demonstrates lower procedural morbidity (permanent neurological deficits in 2.6%, mortality 0.9%) compared to surgical clipping 6, 7
Treatment-related adverse events occur in 15.4% of cases, with thromboembolic complications being the primary concern 6, 7

Aneurysms with favorable neck anatomy (neck diameter <5mm and neck-to-dome ratio <0.5) are ideal for endovascular coil embolization 2
Posterior circulation aneurysms (basilar apex, vertebrobasilar confluence) show advantage with endovascular repair 3
Patients with significant cardiac disease, carotid stenosis, or other vascular comorbidities may favor endovascular approach over open surgery 2

Treatment must be performed at high-volume centers (>35 cases/year) with experienced cerebrovascular specialists, as operator experience significantly impacts complication rates 2, 3, 8

Angiographic follow-up at 6 months and 1-3 years is essential, particularly after endovascular coiling 2
Aneurysm recurrence occurs in 24.4% of coiled aneurysms over 0.4-3.2 years, with retreatment required in 9.1% 6, 7
The annual risk of bleeding in treated patients is 0.2%, though endovascular coiling rerupture rate is 0.9% annually across all locations 3