Comparison of S.T.O.N.E score with Guy’s stone score as a tool to predict stone clearance rates in patients undergoing percutaneous nephrolithotomy: a single center study

Anoop Handa, Sharat Chandra Dash, Nimit Solanki, Abhishek Shukla, Gagandeep Singh, Aditya Abhishek Jha, Sachin Khandelwal


Background: We aimed to compare the Guy’s stone score and S.T.O.N.E nephrolithometry score and assess their predictive accuracy for percutaneous nephrolithotomy (PCNL) outcomes.  

Methods: A total of 100 patients, who underwent PCNL between Jan 2018 and Dec 2018 were included in the study. All patients were evaluated with computerized tomography (CT) scan preoperatively and scores were calculated. Patient demographic characteristics, intraoperative and postoperative variables were evaluated. The relationship between the Guy’s and S.T.O.N.E scores, and their prediction for postoperative stone-free status, complications were compared.

Results: The mean Guy’s score was 2.04±1.01, and the mean S.T.O.N.E score was 8.0+1.7. The mean operative time was 101.9+41 minutes and the mean blood loss was 170+113ml. The complication rate in our study was found to be 32%, majority were grade 1-2. Both scoring systems showed positive correlation with stone burden, operating time and blood loss. The overall stone free rate was 72% and both the GSS and S.T.O.N.E score were significantly associated with success of the procedure.  

Conclusions: Both Guy’s and S.T.O.N.E scoring systems are equally effective in predicting stone-free status.  


S.T.O.N.E score, Guy’s score, PCNL, Renal stone, Scoring system

Full Text:



Ramello A, Vitale C, Marangella M. Epidemiology of nephrolithiasis. J Nephrol. 2000;13 Suppl 3:S45-50.

Preminger GM, Assimos DG, Lingeman JE, Nakada SY, Pearle MS, Wolf JS. Chapter 1: AUA guideline on management of staghorn calculi: diagnosis and treatment recommendations. J Urol. 2005;173(6):1991-2000.

Zhu W, Liu Y, Liu L, Lei M, Yuan J, Wan SP, et al. Minimally invasive versus standard percutaneous nephrolithotomy: a meta-analysis. Urolithiasis. 2015;43(6):563-70.

Jeong CW, Jung JW, Cha WH, Lee BK, Lee S, Jeong SJ, et al. Seoul National University Renal Stone Complexity Score for predicting stone-free rate after percutaneous nephrolithotomy. PLoS One. 2013;8(6):e65888.

Smith A, Averch TD, Shahrour K, Opondo D, Daels FP, Labate G, et al. A nephrolithometric nomogram to predict treatment success of percutaneous nephrolithotomy. J Urol. 2013;190(1):149-56.

Kumar U, Tomar V, Yadav S, Priyadarshi S, Vyas N, Agarwal N, et al. STONE score versus Guy’s Stone Score - prospective comparative evaluation for success rate and complications in percutaneous nephrolithotomy. Urol Ann. 2018;10(1):76-81.

Magrill D, Patel U, Anson K. Impact of imaging in urolithiasis treatment planning. Curr Opin Urol. 2013;23(2):158-63.

Bozkurt IH, Aydogdu O, Yonguc T, Yarimoglu S, Sen V, Gunlusoy B, et al. Comparison of guy and clinical research office of the endourological society nephrolithometry scoring systems for predicting stone-free status and complication rates after percutaneous nephrolithotomy: a single center study with 437 cases. J Endourol. 2015;29(9):1006-10.

Labadie K, Okhunov Z, Akhavein A. Evaluation and comparison of urolithiasis scoring systems used in percutaneous kidney stone surgery. J Urol. 2015;193(1):154-9.

Noureldin YA, Elkoushy MA, Andonian S. Which is better? Guy’s versus S.T.O.N.E. nephrolithometry scoring systems in predicting stone‐free status postpercutaneous nephrolithotomy. World J Urol. 2015;33:1821-5.

Tailly TO, Okhunov Z, Nadeau BR, Huynh MJ, Labadie K, Akhavein A, et al. Multicenter external validation and comparison of stone scoring systems in predicting outcomes after percutaneous nephrolithotomy. J Endourol. 2016;30(5):594-601.

Okhunov Z, Friedlander JI, George AK, Duty BD, Moreira DM, Srinivasan AK, et al. STONE nephrolithometry: novel surgical classification system for kidney calculi. Urology. 2013;81(6):1154-60.

Mandal S, Goel A, Kathpalia R, Sankhwar S, Singh V, Sinha RJ et al. Prospective evaluation of complications using the modified Clavien grading system, and of success rates of percutaneous nephrolithotomy using Guy’s stone score: a single-center experience. Indian J Urol. 2012;28(4):392-8.

Smith A, Averch TD, Shahrour K, Opondo D, Daels FP, Labate G, Turna B, de la Rosette JJ, Croes Pcnl Study Group. A nephrolithometric nomogram to predict treatment success of percutaneous nephrolithotomy. J Urol. 2013;190(1):149-56.

Vicentini FC, Marchini GS, Mazzucchi E, Claro JF, Srougi M. Utility of the Guy's stone score based on computed tomographic scan findings for predicting percutaneous nephrolithotomy outcomes. Urology. 2014;83(6):1248-53.

Unsal A, Resorlu B, Atmaca AF, Diri A, Goktug HNG, Can CE, et al. Prediction of morbidity and mortality after percutaneous nephrolithotomy by using the Charlson Comorbidity Index. Urology. 2012;79(1):55-60.

Rathee VS, Vivek HC, Khan SW, Singh AK, Shukla PK, Verma A, et al. Comparison of Guy’s vs S.T.O.N.E. nephrolithometry scoring systems in predicting the success rate of PCNL. J Clinic Urol. 2017;10(5):423-9.

Thomas K, Smith NC, Hegarty N, Glass JM. The Guy’s stone score–grading the complexity of percutaneous nephrolithotomy procedures. Urol 2011;78(2):277-81.

Akhavein A, Henriksen C, Syed J, Bird VG. Prediction of single procedure success rate using S.T.O.N.E. nephrolithometry surgical classification system with strict criteria for surgical outcome. Urology. 2015;85(1):69-73.