STONE NEPHROLITHOMETRY FOR EVALUATING STONE CLEARANCE AFTER PERCUTANEOUS NEPHROLITHOTOMY

Stone Nephrolithometry

Abstract

Objective: To calculate stone nephrolithometry score in patients undergoing percutaneous nephrolithotomy (PCNL) and its correlation with stone clearance.
Study Design: Descriptive cross-sectional study. 
Place and Duration of Study: Armed Forces Institute of Urology (AFIU) Rawalpindi, from Jan 2015 till Jul 2015
Material and Methods: A total of 90 patients were included in the study after calculating the sample size using WHO sample calculator. After ethical review committee approval, all patients who fulfilled the inclusion criteria were included in the study by non-probability purposive sampling technique. Five variables available from preoperative non-contrast computed tomography (CT) were measured by a single radiologist then each variable was scored according to predefined score proposed by Okhunov Z and finally stone Nephrolithometry score was calculated by the sum of individual variable scores. Post-operatively stone clearance was assessed by plain x-ray kidney ureter and bladder, done within 1 week after the procedure. The frequency of stone clearance after PCNL at different stone Nephrolithometry scores was determined.
Results: The patient’s mean age was 52.11 ± 16.33 years among which 74.44% patients were males and 25.56% patients were females. The stone nephrolithometry mean score of the patients was 9.36 ± 1.86 and stone clearance was seen in 90% patients. Statistically significant difference was found between the score and stone clearance.
Conclusion: Stone nephrolithometry score is associated with post-PCNL stone clearance rates.