Mini-Percutaneous Nephrolithotomy versus Standard Percutaneous Nephrolithotomy for Stones 2 cm and Above: A Meta-analysis

Abstract

The current standard in the management of large burden renal stones is conventional percutaneous nephrolithotomy. Mini-percutaneous nephrolithotomy (mini-PCNL) is a procedure developed to decrease complications of standard PCNL by decreasing the size of access. Recent studies have shown high stone free rates with minimal complications in utilizing mini-PCNL in larger stones.

Objective: This study aims to assess the safety and efficacy of mini-PCNL for stones with sizes 2 cm and above versus standard PCNL.

Methods: This is a meta-analysis comparing mini-PCNL and standard PCNL in the management of renal stones 2 cm and above. A PUBMED search was done to acquire randomized controlled trials (RCTs), prospective and retrospective studies of mini-PCNL and standard PCNL assessing large burden renal stones, defined as 2 cm and above. Two authors independently assessed the studies for selection. Comparison of mini-PCNL and standard PCNL was done according to following parameters: stone-free rate, operative time, postoperative decrease in hemoglobin levels, length of hospital stay, rate of transfusion, occurrence of fever, postoperative pain scores, and occurrence of urine leakage.

Results: Results of this meta-analysis showed that standard percutaneous nephrolithotomy has an advantage over mini percutaneous nephrolithotomy only in terms of having a shorter operative time for larger stones (MD: 8.44 min, 95% CI 6.36 – 10.52 min, p < 0.00001). No difference was found in the outcomes of postoperative pain scores (MD 0.19 VAS score, %CI 0.16 – 0.54, p = 0.29), occurrence of postoperative fever (OR 0.33, 95% CI 0.18 – 0.61, p = 0.06) and the stone-free rate (OR 0.97, 95% CI 0.67 – 1.41, p = 0.88). Mini-percutaneous nephrolithotomy has advantage over standard percutaneous nephrolithotomy for large-burden stones in terms of shorter length of postoperative hospital stay (MD 1.44 day, 95% CI 1.22-1.66, P <0.00001), lower hemoglobin drop (MD 0.48 mg/dl, 95% CI 0.39–0.66, p < 0.00001), lower rate of transfusion (OR 0.40, 95% CI 0.20 – 0.99, p = 0.01), urine leakage (OR 0.11, 95% CI 0.03 – 0.39, p = 0.0008) and an overall lower occurrence of complications (OR 0.42, 95% CI 0.28 – 0.62, p < 0.0001).

Conclusion: Mini-percutaneous nephrolithotomy is a safe and effective intervention in large-burden stones 2 cm in size and above.