Off-clamp partial nephrectomy has a positive impact on short- and long-term renal function: a systematic review and meta-analysis

BACKGROUND: Ongoing efforts are focused on shortening ischemia intervals as much as possible during partial nephrectomy to preserve renal function. Off-clamp partial nephrectomy (off-PN) has been a common strategy for to avoid ischemia in small renal tumors. Although studies comparing the advantages between off-PN with conventional on-clamp partial nephrectomy (on-PN) have been reported, the impact on short- and especially long-term renal function of the two surgical methods has not been discussed seriously and remained unclear. Our purpose is to evaluate the impact on short- (within postoperative 3 months) and long-term (postoperative 6 months or longer) renal function of off-PN compared with that of on-PN. METHODS: We comprehensively searched databases, including PubMed, EMBASE, and the Cochrane Library, without restrictions on language or region. A systematic review and cumulative meta-analysis of the included studies were performed to assess the impact of the two techniques on short- and long-term renal function. RESULTS: A total of 23 retrospective studies and 2 prospective cohort studies were included. The pooled postoperative short-term decrease of estimated glomerular filtration rate (eGFR) was significantly less in the off-PN group (weighted mean difference [WMD]: 4.81 ml/min/1.73 m(2); 95% confidence interval [CI]: 3.53 to 6.08; p < 0.00001). The short-term increase in creatinine (Cr) level in the on-PN group was also significant (WMD: − 0.05 mg/dl; 95%CI: − 0.09 to − 0.00; p = 0.04). Significant differences between groups was observed for the long-term change and percent (%) change of eGFR (p = 0.04 and p < 0.00001, respectively) but not for long-term Cr change (p = 0.40). The postoperative short-term eGFR and Cr levels, but not the postoperative long-term eGFR, differed significantly between the two groups. The pooled odds ratios for acute renal failure and postoperative progress to chronic kidney disease (stage≥3) in the off-PN group were found to be 0.25 (p = 0.003) and 0.73 (p = 0.34), respectively, compared with the on-PN group. CONCLUSIONS: Off-PN exerts a positive impact on the short- and long-term renal function compared with conventional on-PN. Given the inherent limitations of our included studies, large-volume and well-designed RCTS with extensive follow up are needed to confirm and update the conclusion of this analysis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12882-018-0993-3) contains supplementary material, which is available to authorized users.