Comparison of Guy’s Stone Score and S.T.O.N.E. Nephrolithometry in Predicting Stone-Free Status After Mini-Percutaneous Nephrolithotomy

Muhammad Talha Akhtar; Badar Murtaza; Ghufran Ahmed; Ammar Yasir; Muhammad Farooq Shahid; Asim Aslam

doi:10.51253/pafmj.v76iSUPPL-5.13900

Authors

Muhammad Talha Akhtar Department of General Surgery, Armed Forces Institute of Urology, Rawalpindi/National University of Medical Sciences (NUMS) Pakistan
Badar Murtaza Department of General Surgery, Armed Forces Institute of Urology, Rawalpindi/National University of Medical Sciences (NUMS) Pakistan
Ghufran Ahmed Department of General Surgery, Armed Forces Institute of Urology, Rawalpindi/National University of Medical Sciences (NUMS) Pakistan
Ammar Yasir Department of General Surgery, Armed Forces Institute of Urology, Rawalpindi/National University of Medical Sciences (NUMS) Pakistan
Muhammad Farooq Shahid Department of General Surgery, Armed Forces Institute of Urology, Rawalpindi/National University of Medical Sciences (NUMS) Pakistan
Asim Aslam Department of General Surgery, Armed Forces Institute of Urology, Rawalpindi/National University of Medical Sciences (NUMS) Pakistan

DOI:

https://doi.org/10.51253/pafmj.v76iSUPPL-5.13900

Keywords:

Guy’s Stone Score, Mini-PCNL, Nephrolithiasis, Percutaneous Nephrolithotomy, S.T.O.N.E Score

Abstract

Objective: To compare the performance of the Guy’s score and the S.T.O.N.E. score in predicting stone-free status (SFS) in Pakistani patients undergoing mini-percutaneous nephrolithotomy (mini-PCNL) including single and multiple tracts at a tertiary care hospital of Pakistan.

Study Design: Prospective comparative study.

Place and Duration of Study: Urology department of Armed Forces Institute of Urology, Rawalpindi, Pakistan, from Nov 2024 to May 2025.

Methodology: Adults (18–80 years) with renal calculi on non-contrast CT-KUB undergoing mini-PCNL were enrolled. Demographics and CT parameters were recorded, and Guy’s Stone Score (GSS) and S.T.O.N.E. score were calculated. Stone-free status (SFS) was residual fragments ≤4 mm on postoperative day-1 X-ray KUB.

Results: One hundred-and-ten patients, out of which 79(72.0%) were male, and the mean age was 42.6±11.3 years, underwent mini-PCNL. Lower-pole access was used in 89(81.0%) patients and double-J stents in all. Nephrostomy was placed in 20(18.2%) patients. SFS was achieved in 91(82.7%). Groups were similar in age, sex, creatinine, and laterality. Mean GSS and S.T.O.N.E. were lower in SFS (1.8±0.95 and 5.81±1.14 p<0.001) than non-SFS (3.2±1.03 and 7.11±1.79 p=0.002). GSS showed AUC 0.83 (95% CI 0.72–0.92) versus S.T.O.N.E. 0.72 (0.57–0.86), with a p value of 0.017.

Conclusion: Our results show that both GSS and S.T.O.N.E. meaningfully stratify the likelihood of stone free status (SFS) after mini-PCNL however GSS can better predict SFS as compared to S.T.O.N.E score.

Downloads

Download data is not yet available.

References

1. Hashmi SB, Sarwar H, Younus N, Khalid M, Majid H. Urolithiasis diagnosis: The critical role of stone composition analysis for improved patient outcomes. Pak J Pathol 2026; 37(1): 48-54. https://doi.org/10.55629/pakjpathol.v37i1.924

2. Imtiaz S, Alam A. Epidemiology and demography of chronic kidney disease in Pakistan—a review of Pakistani literature. Pak J Kidney Dis 2023; 7(1): 2–7.

https://doi.org/10.53778/pjkd71209

3. Lezrek M, Durutovic O. PCNL in developing countries. In: Denstedt JD, Liatsikos EN, editors. Percutaneous Renal Surgery. Springer; 2023: 401-413. Available from:

https://link.springer.com/chapter/10.1007/978-3-031-40542-6_27

4. Shoaib MW, Subhani MH, Khan SM, Alamgir AR. Prevalence of diabetes mellitus in patients with renal stones: a single center experience. Ann Punjab Med Coll 2023; 17(1): 11–13. https://doi.org/10.29054/apmc/2023.1450

5. Skolarikos A, Geraghty R, Somani B, Tailly T, Jung H, Neisius A, et al. European association of urology guidelines on the diagnosis and treatment of urolithiasis. Eur Urol 2025; 88(1): 64-75. https://doi.org/10.1016/j.eururo.2025.03.011

6. Bhatti KH, Bapir R, Gomha FS, Abdalla BA, Sohail N, Fattah FH, et al. Ethnic diversity and urolithiasis: a single-center experience. Int Urol Nephrol 2025; 57(7): 2107-2117.

https://doi.org/10.1007/s11255-025-04387-4

7. Bryniarski P, Paradysz A, Zyczkowski M. A randomized controlled study to analyze the safety and efficacy of percutaneous nephrolithotripsy and retrograde intrarenal surgery in the management of renal stones more than 2 cm in diameter. J Endourol 2012; 26(1): 52–57.

https://doi.org/10.1089/end.2011.0235

8. Poudyal S, Pradhan M, Chapagain S. Comparison of GSS and S.T.O.N.E. for predicting PCNL outcome. J Urol Res 2017; 4(2): 1082.

9. Okhunov Z, Friedlander JI, George AK, Duty BD, Moreira DM, Srinivasan AK, et al. S.T.O.N.E. nephrolithometry: novel surgical classification system for kidney calculi. Urology 2013; 81(6): 1154–1160. https://doi.org/10.1016/j.urology.2012.10.083

10. Lai S, Jiao B, Jiang Z, Zhao X, Chen J, Zhang H, et al. Comparing different kidney stone scoring systems for predicting PCNL outcomes: multicenter cohort. Int J Surg 2020; 81: 55–60.

https://doi.org/10.1016/j.ijsu.2020.07.025

11. Çetin T, Gülpınar MT, Keskin M. Guy’s, S.T.O.N.E., CROES nomograms in percutaneous nephrolithotomy can predict the stone-free rate similarly: a retrospective study of thousand patients. J Urol Surg 2024; 11(3): 179–186.

https://doi.org/10.4274/jus.galenos.2024.2024-3-11

12. Mazzon G, Castellan P, Viola M. Reliability of nephrolithometric nomograms in mini-PCNL: a systematic evaluation. Ther Adv Urol 2022; 14: 17562872231196676.

https://doi.org/10.1016/j.ajur.2022.02.010

13. Biswas K, Gupta SK, Tak GR, Ahmed K, Mahajan A, Singh P, et al. Comparison of S.T.O.N.E. score vs GSS vs CROES as predictors of PCNL outcome: prospective study (n=252). BJU Int 2020; 126(2): 246–253.

https://doi.org/10.1111/bju.15130

14. Shahab S, Galeti EH, Bharali MD. Comparative study between GSS, S.T.O.N.E., and CROES in predicting SFR after PCNL: a prospective analysis (n=50). J Dr NTR Univ Health Sci 2022; 11: 336–343. https://doi.org/10.4103/jdrntruhs.jdrntruhs_42_22

15. Thomas K, Smith NC, Hegarty N, Glass JM. The Guy’s stone score—grading the complexity of PCNL procedures. Urology 2011; 78(2): 277–281.

https://doi.org/10.1016/j.urology.2010.12.026

16. Li H, Xue X, Meng G, He C, Tong L, Lai Y et al. The roles of bacteria on urolithiasis progression and associated compounds. Biochem Pharmacol 2025; 237: 116958.

https://doi.org/10.1016/j.bcp.2025.116958

17. Sanjaya IDGR, Tirtayasa PMW, Natawijaya R. Guy’s stone score vs STONE score for predicting SFR after PCNL in Indonesia. Indones J Urol 2021; 28(1): 1–7.

https://doi.org/10.32421/juri.v28i1.703

18. Ahmed F, Al-Kohlany K, Al-Naggar K, Alnadhari I, Altam AY, Badheeb M, et al. Assessing the predictive accuracy of the STONE score for stone-free rates in semirigid pneumatic ureteral lithotripsy: implications for validation. Res Rep Urol 2025; 17: 139–152.

https://doi.org/0.2147/RRU.S515846