Repositioning lower pole stones prior to lithotripsy in retrograde intrarenal surgery as a strategy to enhance stone free rate: A systematic review, meta-analysis, and meta-regression

Abstract

Lower pole stones (LPS) are associated with the difficulty to achieve a total stone-free rate (SFR) of any location in the urinary tract. Several studies have suggested that the repositioning of LPS in Retrograde Intrarenal Surgery (RIRS) could improve the SFR. Thus, the aim of this systematic review was to assess the efficacy of the LPS repositioning prior to lithotripsy in retrograde intrarenal surgery. A systematic search was conducted across five databases (PubMed, Scopus, Embase, Web of Science, and Scilit) to identify studies available up to August 1, 2023. Studies were included if they reported the repositioning of LPS before lithotripsy versus in-situ lithotripsy. Quality assessment was carried out using ‘Cochrane Risk of Bias 2.0’ and ‘Newcastle Ottawa Scale’ depending on the study design. Meta-analyses and meta-regression analyses were performed using random-effects models to account for between-study heterogeneity. Pooled effect estimates were expressed as odds ratios (ORs) or standardized mean differences (SMDs), together with their corresponding 95% confidence intervals (95% CIs). Pooled analysis of seven studies (n=496 patients) suggested that the repositioning LPS significantly improved SFR (7 studies; OR: 3.40; 95%CI: 1.86–6.22; p<0.001). The SFR increased from 79% (95%CI: 72–86%) to 95% (95%CI: 92–98%) when the repositioning was performed. The incidence of complications did not differ significantly between the experimental and control groups (4 studies; OR: 1.87; 95%CI: 0.90–3.30; p=0.11). Nonetheless, patients in the experimental group received longer operative time (3 studies; SMD=1.36; 95%CI: 0.3–2.42; p<0.001). Meta-regression suggested that SFR was not dependent on age, gender, stone size, and follow-up duration (all p>0.05). In conclusion, repositioning the lower pole stone before lithotripsy during RIRS yields better results than in-situ lithotripsy, despite the extended duration of the operative procedure.