Treatment outcomes of unruptured intracranial aneurysm; experience of 1231 consecutive aneurysms

Background: The aim of this study was to review our experience with surgical clipping and endovascular treatment (EVT) of unruptured intracranial aneurysms (UIAs), with a special focus on complications. Methods: We retrospectively analyzed clinical and radiological data from patients who underwent surgery or EVT. Surgery was performed by one neurosurgeon, and EVT was performed by two neurointerventionists according to one hybrid neurosurgeon’s decision. Adverse events included the following: (1) decline of the modified Rankin Scale (mRS) score from 1 to 2 and (2) any unexpected neurological deficit or imaging finding affecting the prognosis and/or requiring additional procedures, medication, or prolonged hospital stay. Results: Of the 1231 UIAs in 1124 patients, 625 (50.7 %) aneurysms were treated with surgery, and 606 (49.3 %) aneurysms were treated with EVT. The overall complication rate of UIA treatment was 3.2 %. The rate of adverse events was 2.4 %, and the rates of morbidity and mortality were 0.6 and 0.2 %, respectively. The rates of adverse events, morbidity, and mortality were not significantly different between surgery and EVT. The rate of hospital use for EVT was stationary over the years of the study. Posterior circulation in surgery, large aneurysms (>15 mm) in EVT, and stent- or balloon-assisted procedures in EVT were associated with the occurrence of complications. Poor clinical outcome (mRS of 3–6) was 0.8 % at hospital discharge. Conclusions: Both UIA treatment modalities decided by one hybrid neurosurgeon showed low complication rates and good clinical outcomes in this study. These results may serve as a point of reference for clinical decision-making for patients with UIA.