Calcium phosphate content does not affect stone-free rate after percutaneous nephrolithotomy

Area of Science:

• Urology
• Nephrology
• Biochemistry

Background:

• Percutaneous nephrostolithotomy (PCNL) is a common procedure for kidney stone removal.
• Previous studies suggested lower stone-free rates in patients with calcium phosphate stones.
• This study aimed to investigate the association between calcium phosphate content and PCNL outcomes.

Purpose of the Study:

• To evaluate the impact of calcium phosphate stone composition on the stone-free rate after percutaneous nephrostolithotomy.
• To identify factors predicting procedural failure in PCNL.
• To clarify the relationship between stone burden, stone composition, and PCNL success.

Main Methods:

• Retrospective review of 188 patients undergoing unilateral PCNL.
• Stones stratified by size (≤2 cm, >2 cm, partial/complete staghorn) and calcium phosphate content (0%, 1-10%, 11-60%, >60%).
• Procedural failure defined as >2 mm residual fragments on postoperative CT scan; multivariate logistic regression used for analysis.

Main Results:

• Overall, 57% of stones had calcium phosphate components; 37.8% of procedures were classified as failures.
• Increasing stone size correlated with decreased stone-free rates (p=0.009).
• No significant association was found between calcium phosphate content and procedural failure (p=0.68) or residual stone fragments (p=0.67).

Conclusions:

• Calcium phosphate stone composition is not a predictor of poor stone-free rates after PCNL.
• Stone size remains a significant factor influencing PCNL outcomes.
• Findings do not support previous research suggesting a negative impact of calcium phosphate stones on PCNL success.