Statistical analysis
The variables were investigated using visual (histograms, probability plots) and analytical methods (Kolmogorov–Smirnov/Shapiro–Wilk test) to determine the normality of their distribution. Normally distributed continuous variables were expresses as mean ± standard deviation (SD) or median values with range if not normally distributed. Categorical variables were expressed as number and percentages. Demographic parameters, operating variables and follow-up data were compared using the Mann-Whitney U test and chi-square test. Wilcoxon test was conducted to analyze pre-operative and follow-up diameter of aneurysm sac. Kaplan-Meier analysis was conducted to demonstrate freedom from all-cause mortality and freedom from secondary interventions. The hazard ratio (HR) and 95% confidence intervals (CI) were estimated with different Cox proportional hazard models to estimate the independent predictors of survival with adjustment of the predefined possible rick factors. A p value of < 0.05 was considered to be statistically significant, and all statistical analyses were performed using the SPSS for Windows version 15.0 statistical software program (SPSS Inc., Chicago, IL, USA).