BACKGROUND: We explored the impact of various craniotomy approaches on the outcomes and long-term cognitive function of microsurgical clipping for superiorly projecting anterior communicating artery (ACoA) aneurysms. METHODS: We retrospectively analyzed 127 superiorly projected ACoA aneurysms that underwent microsurgical clipping between January 2014 and January 2022. Patients were categorized into 2 types: type 1 (n = 70), characterized by the posterior positioning of the ipsilateral A2 segment (open A2 plane side)
and type 2 (n = 57), characterized by the anterior positioning of the ipsilateral A2 segment (closed A2 plane side). The analysis focused on clinical outcomes (modified Rankin Scale score) and long-term cognitive function (Montreal Cognitive Assessment). RESULTS: No significant differences in initial attributes were observed between the 2 groups. No differences were found in modified Rankin Scale score (P = 0.483), cognitive impairment (P = 0.190), or severe cognitive impairment (P = 0.332) between the 2 groups. Furthermore, no significant differences in delayed cerebral ischemia (P = 0.852), delayed bleeding (P = 0.912), or intraoperative rupture (P = 0.141) was found between the 2 groups. However, the occurrence of Montreal Cognitive Assessment subcategories of postponed memory items (P <
0.05) and conceptualization items (P <
0.05) demonstrated a significant decrease on the accessible A2 plane side during a shorter operative time (P = 0.03) and reduced gyrus rectus aspiration frequency (P <
0.001). CONCLUSIONS: The anterior position of the A2 segment can offer better visualization of the aneurysm dome, bilateral A2, and AcoA, leading to reduced operative time and gyrus rectus aspiration frequency, potentially enhancing long-term cognitive function.