Prevalence of ruptured small and very small aneurysms: a retrospective single-centre study.

In this series, over 21% of patients suffered from SAH resulting from ruptured small aneurysms (≤ 5 mm), with 12% specifically attributed to ruptured very small aneurysms (≤ 3 mm), despite large aneurysms (> 7 mm) being the most prevalent source of bleeding in 40% of cases. A worse prognosis was primarily associated with the severity of SAH, reflected in poorer clinical status at admission and older age. Endovascular embolisation was found to be effective and associated with better outcomes compared to surgical treatment.