Objective: To compare safety and efficacy of bilateral single-session mini-percutaneous nephrolithotomy (BSS-Mini-PNL) vs staged-Mini-PNL.

Patients and methods: Adult patients with bilateral renal stones indicated for PNL were managed with BSS-Mini-PNL (45 patients and 90 renal units) and prospectively compared vs staged-Mini-PNL (55 patients and 110 renal units) between July 2014 and December 2017. Mini-PNL was done through 18-Fr tract in prone position under regional anesthesia and fluoroscopy using pneumatic lithotripsy. A semirigid ureteroscope (8.5/11.5 Fr) was used. Mann-Whitney, Student t, chi-square, or Fisher's exact tests were used as appropriate.

Results: Both groups were comparable in characteristics of stones and patients. Stone burden was 3.36 ± 1.61 vs 3.38 ± 1.18 cm2 in BSS-Mini-PNL vs staged-Mini-PNL, respectively. Staghorn stones were present in 13.3% vs 8.2% in BSS-Mini-PNL vs staged-Mini-PNL, respectively. There was no significant difference in the number of required tracts (1.34 ± 0.6 vs 1.25 ± 0.51 tract/renal unit) as well as the rate of tubeless Mini-PNL (81.1% vs 85.5%) or stone-free rate (90% vs 92.7%) in BSS-Mini-PNL vs staged-Mini-PNL, respectively. BSS-Mini-PNL had significantly shorter operative time (126.22 ± 37.2 vs 169.63 ± 61.28 minutes), shorter hospital stay (2 [1-8] vs 4 [2-16] days) and higher hemoglobin loss (1.1 [0.1-2.8] vs 0.5 [0.1-2.17] gm/d) than staged-Mini-PNL. The complications profile (17.8% vs 13.6%) and rate of blood transfusion (4.4% vs 3.6%) were comparable in BSS-Mini-PNL vs staged-Mini-PNL, respectively, without significant difference.

Conclusion: BSS-Mini-PNL is comparable to staged-PNL as regard stone-free rate and complications according to the selection criteria of the present study. However, BSS-Mini-PNL is associated with significant reduction in the cumulative operative time and hospital stay, which are reflected on the overall cost.