Seven studies were involved in our study[1, 7, 11-15]. The literature searching process is summarized in Fig. 1. From the PubMed, EMBASE and the Cochrane Central Register, we acquired 2296 studies. After precise search, we included 245 studies. After further processing, we excluded 104 studies. Finally, 7 studies meet inclusion cretia were included in this meta-analysis.
Operating time
Our study showed no statistical differences between the RPN group and LPN group (n=940, 477 patients in the RPN group, 463 patients in LPN group, WMD: -22.45, 95%CI: -35.06 to-9.85, I2 =85%; p=0.18, random-effects model, Fig.2).
Estimated blood loss
Data of estimated blood loss were avaliable in four studies. No statistically significant difference in estimated blood loss between the RPN and LPN groups (n =824, 419 patients were in the RPN group, and 405 patients were in the LPN group, WMD: 34.49, 95% CI -75.16-144.14, p=0.54, random-effects model, Fig.3).
Warm ischemia time
The data of warm ischemia time were in four studies. There was a statistically significant difference in warm ischemia time between the RPN and LPN groups (n =824, 419 patients were in the RPN group, and 405 patients were in the LPN group, WMD: -6.96, 95% CI -7.30–-6.62, p <0.0001, I2=0, random-effects model, Fig.4).
Transfusion
Seven studies reported the transfusion in our meta-analysis. There no statistically significant difference in transfusion between the RPN and LPN groups (n =1307, 635 patients were in the RPN group, 672 patients were in the LPN group, OR: 0.72, 95% CI 0.48–1.08, p =0.11, I2 =0, fixed-effective model, Fig.5).
Conversion
The pooled data showed that a significant statistical differences between the RPN group and LPN group (n=1132, OR: 0.34, 95%CI: 0.17 to 0.66, I2=53%; p=0.002, fixed-effects model, Fig.6).
Hospital stay
We included four studies in this study. No statistically significant difference in the hospital stay between the RPN and LPN groups (n =824, 419 patients were in the RPN group, and 405 patients were in the LPN group, WMD: -0.59 95% CI -1.24–0.06, p=0.07, I2=86%, random-effects model, Fig.7).
Intraoperative complications
Five studies reported the intraoperative complications. There was a statistical significant difference in the intraoperative complications between the RPN and LPN groups (n =1040, 527 patients were in the RPN group, and 513 patients were in the LPN group, OR: 0.52, 95% CI 0.28–0.97, p=0.04, I2=0, fixed effects model, Fig.8).
Postoperative complications
Data on postoperative complications were existing in seven studies. There was no statistically significant difference in postoperative complications between the RPN and LPN groups (n =1256, 635 patients were in the RPN group, 621 patients were in the LPN group, OR: 0.85, 95% CI 0.65–1.11, p=0.23, I2=0, fixed-effective model, Fig.9).
Postoperative renal function
Three studies included in our meta-analysis to pool the postoperative renal function. There was a statistically significant difference in the postoperative function between the RPN and LPN groups (n =524, 235 patients were in the RPN group, and 289 patients were in the LPN group, WMD: 3.32, 95% CI 0.73–5.91, p=0.01, I2 =57, random-effects model, Fig.10).
Postive surgical margin
Six studies reported the postive surgical margin. There was no statistically significant difference in the postive surgical margin between the RPN and LPN groups (n =1132, 573 patients were in the RPN group, and 559 patients were in the LPN group, OR: 0.69, 95% CI 0.27–1.78, p=0.45, I2=0, fixed effects model, Fig.11).