STONE score versus Guy's Stone Score - prospective comparative evaluation for success rate and complications in percutaneous nephrolithotomy.

Purpose: The aim of the current study was to compare Guy's score and STONE score in predicting the success and complication rate of percutaneous nephrolithotomy (PCNL).

Materials and Methods: A total of 445 patients were included in the study between July 2015 and December 2016. The patients were given STONE score and Guy's Stone Score (GSS) grades based on CT scan done preoperatively and intra- and post-operative complications were graded using the modified Clavien grading system. The PCNL were done by a standard technique in prone positions.

Results: The success rate in our study was 86.29% and both the GSS and STONE score were significantly associated with a success rate of the procedure. Both the scoring systems correlated with operative time and postoperative hospital stay. Of the total cases, 102 patients (22.92%) experienced complications. A correlation between STONE score stratified into low, moderate, and high nephrolithometry score risk groups (low scores 4-5, moderate scores 6-8, high scores 9-13), and complication was also found ( P = 0.04) but not between the GSS and complication rate ( P = 0.054).

Conclusion: Both GSS and STONE scores are equally effective in predicting success rate of the procedure.