Stone Clearance by Computed Tomography after Percutaneous Nephrolithotomy: A Descriptive Cross-sectional Study

Area of Science:

• Urology
• Medical Imaging
• Nephrolithiasis Management

Background:

• Percutaneous nephrolithotomy (PCNL) offers high stone-free rates but has associated complications.
• Standardized post-operative imaging protocols after PCNL are lacking.
• This study evaluates computed tomography (CT) for assessing stone clearance post-PCNL.

Purpose of the Study:

• To assess residual stone fragments after PCNL using low-dose CT.
• To determine the size and location of residual fragments.
• To compare outcomes between stone-free and residual stone groups.

Main Methods:

• A descriptive, cross-sectional study involving 40 patients undergoing PCNL.
• Low-dose CT (kidney, ureter, bladder) performed 48 hours post-surgery.
• Comparison of patient demographics, stone characteristics, and complications between groups.

Main Results:

• Residual fragments were detected in 11 (27.5%) of 40 patients via low-dose CT.
• Of residual fragments, 63.63% were <4mm and 36.36% were >4mm.
• Mean stone size differed between residual fragment and stone-free groups (352.47 ± 97.47 mm² vs. 254.79 ± 172.68 mm²).

Conclusions:

• Low-dose CT 48 hours post-PCNL identifies residual stones in approximately one-fourth of patients.
• The majority of detected residual fragments are small (<4mm).
• Intra-operative fluoroscopic clearance may overestimate stone clearance, as significant residual fragments (>4mm) can persist.