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

A proposed mathematical model to help preoperative planning between RIRS and MiniPerc for renal stones between 10 and 20 mm using holmium:Yag laser (Cyber Ho): the stone management according to size-hardness (SMASH) score

To evaluate the performance of a mathematical model to drive preoperative planning between RIRS and MiniPerc (MP) for the treatment of renal stones between 10 and 20 mm. Patients with a renal stone between 10 and 20 mm were enrolled. A mathematical model named Stone Management According to Size-Hardness (SMASH) score was calculated: hounsfield units (HU) χ stone maximum size (cm)/100. Patients were divided into 4 groups: RIRS with score < 15 (Group A), RIRS with score ≥ 15 (Group B), MP with score < 15 (Group C), MP with score ≥ 15 (Group D). Cyber Ho device was always used. Stone free rate (SFR) was assessed after 3 months. Complication rate and need for auxiliary procedures were evaluated. Between January 2019 and December 2021, 350 patients were enrolled (87, 88, 82 and 93 in Groups A, B, C and D). Mean stone size was 13.1 vs 13.3 mm in Group A vs B (p = 0.18) and 16.2 vs 18.1 mm in Group C vs D (p = 0.12). SFR was 82%, 61%, 75% and 85% for Groups A, B, C and D. SFR was comparable between Groups C and D (p = 0.32) and Groups A and C (p = 0.22). SFR was significantly higher in Group A over B (p = 0.03) and in Group D over B (p = 0.02). Complication rate was 2.2%, 3.4%, 12.1%, 12.9% for Groups A, B, C, D. RIRS and MP are both safe and effective. The mathematical model with the proposed cut-off allowed a proper allocation of patients between endoscopic and percutaneous approaches.Registration number of the study ISRCTN55546280.

Clinical Utility of S.T.O.N.E, Guy's Scoring System, and Renal Stone Complexity Scoring in Predicting Outcome of Single-Tract Percutaneous Nephrolithotomy

BACKGROUND

Several imaging-based scores have been developed to predict postoperative stone-free state (SFS) and complications. This study aimed to assess the accuracy of the S.T.O.N.E., Guy Scoring System (GSS), and Seoul National University Renal Stone Complexity (S-ReSCS) scores in predicting the outcomes of single-tract percutaneous nephrolithotomy (ST-PCNL). This scoring system holds paramount importance for low-income and low-middle-income countries (LMICs), as it is inexpensive and cost-effective for the healthcare system.

METHODOLOGY

This retrospective study was carried out with 147 participants. Based on the preoperative computerized tomographic (CT) scan, each patient's S.T.O.N.E. score, GSS, and S-ReSCS were recorded. The modified Clavien grading system was used to document intra- and postoperative complications.

RESULTS

The mean age of the sample population was 45 years. SFS was achieved in 110 (74.8%) patients. The number of calyces involved (p = 0.008), S.T.O.N.E. scoring (p = 0.001), GSS (p = 0.008), and S-ReSCS (0.001) correlated well with the SFS. Forty-nine (33.33%) patients developed complications. The most common complications fell within Clavien grade II. No statistical significance was noted between the S.T.O.N.E. score, GSS, and S-ReSCS with the modified Clavien grading system.

CONCLUSION

The S.T.O.N.E. scoring, GSS, and S-ReSCS have a high predictive value for achieving SFS in ST-PCNL. In addition, findings from LMICs are comparable with those from the rest of the world.