Value of computed tomography in predicting the outcome of percutaneous nephrolithotomy for renal calculi

Abstract

Percutaneous nephrolithotomy (PCNL) is a well known and effective method that has been performed for a long time with higher success rates than other minimally invasive options in the management of large or complex renal stones. Fluoroscopic imaging is commonly used in PCNL surgeries for entering the renal collecting system, viewing renal anatomy, checking for the proper placement of surgical tools, and observing and locating residual stones. The present study aimed to evaluate the computed tomography in predicting outcome of treatment by PCNL of renal calculi. In the current study, the treatment success rate was 50.0 %. Regarding the predictors of treatment outcome in the present study, it was found that successful cases had smaller stone and smaller total stone size and higher HU density when compared with failed cases. Also, the present study found that at a cut-off of 540 HU, CT had a sensitivity of 80.0, a specificity of 100, a PPV of 100.0 % and a NPV of 83.0 % for predicting treatment outcome in PCNL. In conclusion:CT can predict the outcome of PCNL related to the following factors: 1. Configuration of calyces 2. Congenital malformation of the kidney 3. Multiplicity of the stone 4. Location of the stone(lower,middle,upper calyces) 5. Size of the stone 6. Degree of hydronephrosis(mild,moderate,severe) 7. The stone density 8. Associated complications