Stone disease of the renal system is a challenging problem in urologic practice particularly in our area because of the large stone burden and recurrence. Scoring systems are beneficial to counsel the patients about the success and complication rates before surgery.
To compare two widely used scoring systems, namely Guy's and S.T.O.N.E. nephrolithometry scores in predicting the outcomes of ultrasound-guided PCNL.
MATERIALS AND METHODS:
In this prospective study, a total of 50 patients underwent PCNL in Al-Imamein Kadhimein Medical City from 1st of October 2018 to 1stof August 2019 and were enrolled. Guy's and S.T.O.N.E. scores were based on non-enhanced CT scan of abdomen and pelvis. Complications were graded using the Clavien-Dindo classification system. Ultrasound was used to guide PCNL in all cases.
In our study the median age, body mass index (BMI) and stone size were 34.5 years, 31.4 kg/m2 and 765 mm2, respectively. The overall stone-free status was 82%. All complications were grades I-II (60%). The average operative time was 150 minutes. The stone-free status and complications rate were significantly associated with Guy’s score (P < 0.001, P < 0.001) and S.T.O.N.E. score (P < 0.001, P < 0.001), respectively. Moreover, there was a significant positive correlation between Guy's and S.T.O.N.E scores with length of hospital stay (r = 0.277, p < 0.001; r = 0.544, p < 0.001), operative time(r = 0.449, p = 0.001; r = 0.573, p < 0.001) and need for blood transfusion (r = 0.573, p < 0.001; r = 0.568, p < 0.001) respectively. In addition, both Guy's and S.T.O.N.E systems were significantly predictive of stone-free status, need for blood transfusion, operative time and length of hospital stay. The receiver operating characteristic (ROC) showed no significant difference in area under the Guy's and STONE curve (AUC = 0.877 vs. 0.821; p = 0.51).
Both Guy’s and S.T.O.N.E. scoring systems showed a comparable efficacy in predicting the outcomes of PCNL such as stone-free status, necessity for blood transfusion, operative time and length of hospital stay.