Role of Preoperative Renal Stone Complexity Assessment by Guy's Stone Score as a Predictor of Percutaneous Nephrolithotomy Outcomes

Introduction: Various nephrolithometric scoring systems have recently emerged to predict the outcomes of percutaneous nephrolithotomy (PCNL). However, there is no consensus upon an ideal tool. The current study aimed to assess the correlation between Guy's stone score (GSS) and PCNL outcomes. Method: This was a hospital-based observational study of 2-year duration. All patients electively undergoing PCNL for renal stones during the study period were included. Based on the imaging findings, the stones were categorized as simple (GSS I & II) and complex (GSS III & IV). The association between GSS and duration of the procedure, the number of percutaneous tracts needed, stone-free rate (SFR), and the severity of complications based on modified Clavien classification and postoperative stay were assessed. Results: Total number of the patients studied were 100 (n = 100), and most of the patients were in the category of GSS II (51%). Post-extrapolation of χ₂ to Pearson's test, GSS demonstrated a significant association with duration of surgery, the number of percutaneous tracts needed, the severity of complications, and SFR. Conclusions: Preoperative assessment of stone complexity by using GSS effectively correlated with SFR as well as other PCNL outcomes. Hence, we recommend utilizing this predictive tool for standardized documentation, preoperative planning, and better patient counseling.