Fig. 1.

Forest plot demonstrating the meta-analysis of percutaneous nephrolithotomy (PCNL) versus extracorporeal shockwave lithotripsy (ESWL) for the outcome of stone-free rate at 3 months for lower pole stones ≤20mm. Albala and colleagues (2001) [13] and Yuruk and colleagues (2010) [26] reported outcomes for lower pole stones <20 mm. Albala and colleagues [13] also reported outcomes for stones ≤10 mm and 11–20 mm (see Table 1 in Donaldson and colleagues [28]). CI confidence interval, df degrees of freedom, M-H Mantel–Haenszel