2.5 Statistical analyses
After examining variance equivalence and normal distribution, a nonparametric Mann-Whitney U test was applied to assess the difference between pre-treatment and post-treatment serum concentration of MMP-9, while Chi-squared test was employed to evaluate the correlation between outcomes of patients and clinical characters. Parameters that were statistically significant in the Chi-squared test were further carried out in the binary multiple logistic regression analysis. All analysis was performed with SPSS version 22.0 and the figures were completed with GraphPad version 7.04. A P value <0.05 was considered to be significant.