Comparison of intrarenal pelvic pressure and postoperative fever between standard- and mini-tract percutaneous nephrolithotomy: a systematic review and meta-analysis of randomized controlled trials.

Background: High intrarenal pelvic pressure (IPP) induces systemic absorption of irrigation fluid containing bacteria or endotoxins, which is associated with postoperative fever (POF) and even urosepsis. The emphasis of this meta-analysis lies in comparison of IPP and POF between mini-tract percutaneous nephrolithotomy (MPCNL) and standard-tract percutaneous nephrolithotomy (SPCNL).

Methods: Eligible randomized controlled trials (RCTs) were identified from electronic databases from inception to November 2019. Studies selection, quality assessment, data extraction and analysis were accomplished by two independent reviewers using Cochrane Collaboration's tools.

Results: Patients in the MPCNL group experienced higher IPP compared to SPCNL group [mean difference (MD): 8.31, 95% confidence interval (CI): 3.67-12.96, P=0.0005] with highly between-study heterogeneity (P=0.001, I=85%). Notably, the IPP was higher in MPCNL group in different stages of the procedure including introduction, fragmentation and end. However, only two trials were available for pooled analysis. Additionally, the risk of POF in MPCNL was 2.43 times higher than that in SPCNL [odds ratio (OR): 2.43, 95% CI: 1.39-4.27, P=0.002] with no significant between-study heterogeneity (P=0.83, I=0%). The two procedures was comparable on stone-free rate (SFR) (OR: 1.06, 95% CI: 0.61-1.86, P=0.83) and operation time (MD: 5.69, 95% CI: -4.54 to 15.91, P=0.28).

Conclusions: Current evidence indicates that MPCNL is an effective alternative to SPCNL with comparable SFR. IPP and POF is significantly higher during MPCNL compared to SPCNL. Intraoperative detection of IPP is of great significance for ensuring safety and reducing postoperative complications, especially for patients with MPCNL and the duration of stone fragmentation. Further large well-designed trials are warranted to confirm our findings.