Background and Purpose-The natural history of unruptured intracranial aneurysms remains unclear, and management strategy is not well defined. Methods-From January 2003 to December 2012, we enrolled patients with aneurysm in our institution. In total, 2252 patients with 2897 aneurysms were eligible for analysis, and 1960 eligible aneurysms were conservatively managed. Precise 3-dimensional evaluation was conducted using computed tomography angiography, digital subtraction angiography, or magnetic resonance angiography. We then assessed the risk of aneurysm rupture, mortality, and morbidity associated with aneurysm characteristics, demographics, and known health/lifestyle risk factors. Results-The mean follow-up duration was 7388 aneurysm-years. During observation, 56 aneurysms ruptured, resulting in an overall rupture rate per year of 0.76% (95% confidence interval, 0.58-0.98). The mean initial visit to rupture interval was 547 days. Aneurysm size, location, daughter sac, and history of subarachnoid hemorrhage were significant independent predictors for aneurysm rupture. Aneurysms that were ≥5 mm were associated with a significantly increased risk of rupture when compared with 2-to 4-mm aneurysms (unadjusted hazard ratio, 12.24; 95% confidence interval, 7.15-20.93). Of 56 patients who experienced hemorrhage, 29 (52 %) died or were rendered severely disabled. Of the patients who had large or giant aneurysms, none recovered without deficits, and the mortality rate after rupture was 69%. For aneurysms sized <5 mm, the mortality rate was 18%. Conclusions-Larger

Backgrounds and Purpose-The authors evaluated the incidence of rupture of unruptured intracranial saccular aneurysm during observation. Methods-Between January 2003 and December 2006, a total of 419 patients with 529 unruptured intracranial saccular aneurysms were observed without treatment. The mean follow-up duration was 905.3 days. Aneurysm size was measured by 3-dimensional CT angiography. Clinical and 3-dimensional CT angiography follow-up were obtained every 6 months. Results-Nineteen aneurysms ruptured during observation resulting in a 1.4% rupture rate per year. A history of subarachnoid hemorrhage (hazard ratio, 7.3; 95% CI, 2.5 to 21.2), posterior circulation aneurysm (hazard ratio, 2.9; 95% CI, 1.1 to 8), and large size were significant independent predictors for aneurysm rupture. Conclusions Clinical Materials and MethodsFrom January 2003 through December 2006, a total of 419 patients with 529 UIAs were referred to our institution. Patient information and clinical presentation is summarized in Table 1.Size of the UIAs was measured by 3-dimensional CT angiography (Sensation16, Siemens, Germany). Based on the findings of 3-dimensional CT angiography, all UIAs were classified into the following categories: small (S; 0 to 4.9 mm in diameter), medium/ small (MS; 5 to 9.9 mm in diameter with small neck (0 to 3.9 mm), medium/wide (MW; 5 to 9.9 mm in diameter) with a wide neck (Ͼ4 mm), large (L; Ͼ10 mm), and giant (G; Ͼ25 mm). These aneurysms were followed by 3-dimensional CT angiography every 6 months.Data were analyzed using the biomedical data package statistical program (Version 7.0; BMDP Statistical Software, Inc, University of California, Los Angeles, Calif). Categorical variables were compared using the Fisher exact 2-tailed test, the Pearson 2 test, or the test for determining linear trend. Continuous variables were compared among groups by using the Mann-Whitney U test or the Student t test. For life-table analysis and Cox proportional hazards regression model, each patient was followed to the time of subarachnoid hemorrhage (SAH), death due to causes other than SAH, or to the last possible follow-up contact. The average annual incidence of SAH was calculated by determining the number of first-event SAH divided by the number of person-years of follow-up. Cumulative rates of SAH were estimated using the Kaplan-Meier product-limit method. ResultsNineteen aneurysms ruptured during the follow-up period. The annual incidence of SAH was 1.4% during observation. Incidence of rupture was strongly correlated with aneurysm size. The annual rupture rate by size classification was 0.8% (S), 1.2% (M), 7.1% (L), and 43.1% (G), respectively. Details of ruptured aneurysms under conservative observation are summarized in Table 2.In patients with a history of SAH, the hazard ratio (HR) was 7.3 (95% CI, 2.5 to 21.2, PϽ0.001). Particularly in S-sized UIAs, 2 of 8 (25%) were associated with a history of SAH. The risk of rupture in S-sized UIAs with a history of SAH was 5.5 (95% CI, 0.9 to 32.4) compared with patients ...

A combined endovascular and surgical approach conducted in a hybrid OR provides a new strategy for the treatment of complex neurovascular diseases.

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