Association of anterior communicating artery location with rupture in small intracranial aneurysms less than 5 mm: a retrospective analysis.

Despite intracranial aneurysms smaller than 5 mm are generally considered to have a low risk of rupture, management of those located at the anterior communicating artery (ACoA) remains a significant clinical challenge. This study examined the association between ACoA location and rupture tendency in aneurysms smaller than 5 mm. We retrospectively reviewed patients diagnosed with intracranial aneurysms at our institution from January 2015 to September 2022. After excluding unruptured aneurysms, re-ruptures at previous surgical sites, and aneurysms with fusiform, dissecting, or blood blister morphology, 381 cases were analyzed. Clinical and radiological data were collected, with subgroup comparisons based on aneurysm size (< 5 mm vs. ≥5 mm). Logistic regression was used to identify factors associated with rupture in small aneurysms. The ACoA was the most frequent rupture site (31.2%). The diameter at the ACoA was also significantly smaller than that at other locations (5.6 ± 2.5 mm vs. 6.5 ± 3.5 mm; P = 0.008). Subgroup analysis confirmed that ACoA location was associated with a disproportionately elevated rupture rate among smaller aneurysms (P = 0.030). Logistic regression identified ACoA site as an independent predictor of rupture in aneurysms smaller than 5 mm (adjusted odds ratio [OR], 1.646; 95% CI, 1.030-2.629; P = 0.037). In this cohort of ruptured aneurysms, ACoA location was associated with a higher likelihood of rupture among small (< 5 mm) aneurysms, suggesting a potential site-related vulnerability.