Determination of Factors Affecting Stone Free Rates of Primary Percutaneous Nephrolithotripsy (PCNL) in a Tertiary Government Hospital

Abstract

Introduction and Objectives: Percutaneous nephrolithotripsy (PCNL) is the first-line treatment for stone burden >2 cm. The aim of this study was to determine factors that would affect stone free rates after PCNL. Preoperative and intra-operative variables were correlated to the patient’s post-operative outcomes to find a link, or lack thereof, to stone-free outcomes.

Methods: A retrospective study of patients who underwent primary PCNL was done over a 1-year period. The association of the stone characteristics (based on Guy stone score), stone burden, operative time, lithotripsy time, number of access tracts, and location of access tracts to the stone-free status were analyzed.

Results: One hundred thirty patients who underwent PCNL were included in this study. Stone free rate was 77.69% (101/130) while 23 of the 29 patients with residual stones (22%) (29/130) required further treatment. The 30-day overall morbidity rate was 8.46% (11/130). Guy stone score (GSS) and stone burden were found to be significantly associated with stone-free status. Patients with GSS grade I had the highest stone-free rate of 95.45% while patients with GSS Grade IV had the lowest stone-free rate at 30.00%. After multivariate analysis, stone burden (OR 1.176; 95% CI 1.084- 1.275; p 0.00) and GSS 4 (OR 15.374; 95% CI 1.164- 202.980; p 0.04) were significant independent risk factors for stone-free status.

Conclusion: Stone clearance and complication rate after PCNL of the present study were 78% and 8.5%, respectively, comparable with published data. A higher Guy’s stone score and a higher stone burden were significantly associated with retained stones post-PCNL.