Statistical analysis
Data entry, processing and statistical analysis were carried out using Review Manager 5.3 (RevMan 2014)10. A meta-analysis was performed to calculate direct estimates of each treatment technique. Interventions for patients, who achieved favourable outcomes, were pooled to evaluate efficacy that was measured by standardized mean difference (SMD) with 95% confidence interval (CI) for operative time and postoperative ABG improvement; and odds ratio (OR) with 95% CI for graft uptake rate. In addition, interventions for patients, who required additional maneuvers or reached serious adverse events, were pooled to evaluate safety that was measured by OR with 95% CI for additional maneuvers rate and complications rate.
According to the heterogeneity of treatment effect across trials using the Chi2 test results and I2-statistics; a fixed-effect model (P ≥ 0.1) or random-effects model (P < 0.1) was used. Also, we used a random-effects model for subgroup analysis.