Abstract: Objective To investigate the efficacy and safety of percutaneous nephroscopy in one-stage oblique supine lithotomy position combined with flexible ureteroscopy in the treatment of complex nephrolithiasis. 
 Methods Databases such as PubMed, Embase, Cochrane Library, Web of science, CNKI, VIP, CBM, Wanfang were retrieved, to collect randomized controlled trials of percutaneous nephrolithotomy in one-stage oblique supinelithotomy position combined with flexible ureteroscopy and percutaneous nephrolithotomy in prone position for complex nephrolithiasis. RevMan 5.4 and Stata 16.0 software were used for Meta-analysis. 
 Results A total of 11 articles and 1 029 patients (511 in the double mirror group and 518 in the control group) were included. Meta-analysis results showed that, compared with the control group, the double mirror group had a higher clearance rate of primary stone(RR=1.24,95%CI:1.16-1.32, P＜0.001), and a lower overall complication rate (RR=0.49, 95%CI: 0.41-0.58, P＜0.001), lower postoperative infection rate (RR=0.52, 95%CI: 0.31-0.87, P=0.010), lower bleeding rate (RR=0.43, 95%CI: 0.22-0.82, P=0.010), lower blood transfusion rate (RR=0.34, 95%CI: 0.13-0.91, P=0.030), shorter length of hospital stay (MD=-1.57, 95%CI: -2.60--0.55, P=0.003), and less intraoperative blood loss (MD=-52.09, 95%CI: -97.71--6.47, P=0.030). There was no significant difference in the final stone clearance rate, duration of operation, and postoperative fever rate.  
 Conclusion Percutaneous nephroscopy in one-stage oblique supine lithotomy position combined with double endoscopy has many advantages, such as high one-stage stone clearance rate, low overall complication rate, low postoperative infection rate, low bleeding rate and blood transfusion rate, less intraoperative blood loss, and shorter length of hospital stay. 

Key words: kidney calculi, nephrolithotomy, percutaneous, complex nephrolithiasis