ObjectiveThe study evaluated the effectiveness and safety of single-stage versus multistage endovascular treatment in subarachnoid hemorrhage patients with Mirror Aneurysms.Materials and MethodsOur research team performed a prospective study, focusing on the radiographic and clinical data of patients diagnosed with subarachnoid hemorrhage, specifically those who presented with Mirror Aneurysms upon admission to our institutions. According to the different endovascular treatment stages, these patients were grouped into the multistage cohort and the single-stage cohort.ResultA total of 216 aneurysms were identified among the 108 patients, with every patient having one ruptured aneurysm. The duration of follow-up was 2 years in both groups. In the single-stage cohort, all 114 aneurysms in 57 patients were managed during a single session. During the 2-year follow-up, it was observed that 49 patients achieved a modified Rankin Scale score <= 2. Five complications were encountered, including cerebral vasospasm in three patients, cerebral hemorrhage in one patient, and thromboembolism in one patient. In the multistage cohort, only the ruptured aneurysm (amounting to 51 in total) received treatment at the initial occurrence, while the remaining 51 aneurysms were addressed subsequently. Throughout the 2-year follow-up period, 46 subjects exhibited a modified Rankin scale score <= 2. Overall, four complications were documented, including cerebral vasospasm in two patients, a subarachnoid hemorrhage in one patient, and thromboembolism in one patient.ConclusionThe safety and effectiveness of both endovascular treatment groups have been verified for patients with Mirror Aneurysms suffering from subarachnoid hemorrhage. If feasible, single-stage embolization should be considered a viable treatment option for these patients.