• Logo
  • SBMUJournals

Evaluation of Nephrolithometric Scoring Systems to Predict Outcomes of Retrograde Intrarenal Surgery

Nejdet Karsiyakali, Emre Karabay, Erkan Erkan, Mustafa Kadihasanoglu



Purpose: The aim of the study was to evaluate the predictive value of nephrolithometric scoring systems used to predict the complexity of renal stones for the outcomes of retrograde intrarenal surgery (RIRS).

Materials and Methods: A total of 81 patients who underwent RIRS for nephrolithiasis between January 2013 and October 2017 were reviewed in this retrospective study. Guy’s Stone Score (GSS), the S.T.O.N.E., Clinical Research Office of the Endourologic Society (CROES), and Seoul National University Renal Stone Complexity (S-ReSC) nephrolithometry scores were assessed by same researcher for each patient from preoperative non-contrast enhanced computed tomography scans. These nephrolithometric scores, stone characteristics and complications were compared in patients with/without residual stone.

Results: The median (IQR) age of patients (37 female/44 male) was 45 (20) years. The median (IQR) stone burden was 139.4 (125.4) mm2 and the mean Hounsfield unit (HU) value was 1034.46±239.56. The stone burden, S.T.O.N.E. and S-ReSC scores were statistically significantly higher and the CROES score was significantly lower in patients with a residual stone (p<0.001, for all). The incidence of residual stones was statistically significantly higher in patients with Grade 3 GSS (p=0.018). While S.T.O.N.E., S-ReSC and CROES were significantly correlated with stone-free rates, GSS failed to correlate with stone-free status.  According to the receiver operating characteristic (ROC) curve analysis, the predictive value of stone burden was higher for residual stones, compared to S-ReSC scoring (p<0.05).

Conclusion: Nephrolithometric scoring systems nomograms used to predict the PCNL success were not superior to stone burden in predicting the RIRS success.


Menon M, Resnick MI. Urinary Lithiasis: etiology, diagnosis, and medical management. Campbell’s Urology, Editor-in-chief: Patrick C. Walsh. Sounders, 2002, Edition 8, Section 96.

Türk C, Neisius A, Petrik A, Seitz C, Skolarikos A, Thomas K, Donaldson JF, Drake T, Grivas N, Ruhayel Y. European Association of Urology Guidelines on Urolithiasis. European Association of Urology Guidelines. 2018.

Akman T, Binbay M, Ozgor F, Ugurlu M, Tekinarslan E, Kezer C, et al. Comparison of percutaneous nephrolithotomy and retrograde flexible nephrolithotripsy for the management of 2-4 cm stones: a matched-pair analysis. BJU Int. 2012;109(9):1384-9.

Breda A, Angerri O. Retrograde intrarenal surgery for kidney stones larger than 2.5 cm. Curr Opin Urol. 2014;24(2):179-83.

Bozkurt OF, Resorlu B, Yildiz Y, Can CE, Unsal A. Retrograde intrarenal surgery versus percutaneous nephrolithotomy in the management of lower-pole renal stones with a diameter of 15 to 20 mm. J Endourol. 2011;25(7):1131-5.

Hyams ES, Monga M, Pearle MS, Antonelli JA, Semins MJ, Assimos DG, et al. A prospective, multi-institutional study of flexible ureteroscopy for proximal ureteral stones smaller than 2 cm. The Journal of urology. 2015;193(1):165-9.

Skolarikos A, Gross AJ, Krebs A, Unal D, Bercowsky E, Eltahawy E, et al. Outcomes of Flexible Ureterorenoscopy for Solitary Renal Stones in the CROES URS Global Study. J Urol. 2015;194(1):137-43.

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

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.

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.

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):1154-9.

Resorlu B, Unsal A, Gulec H, Oztuna D. A new scoring system for predicting stone-free rate after retrograde intrarenal surgery: the "resorlu-unsal stone score". Urology. 2012;80(3):512-8.

Jung JW, Lee BK, Park YH, Lee S, Jeong SJ, Lee SE, et al. Modified Seoul National University Renal Stone Complexity score for retrograde intrarenal surgery. Urolithiasis. 2014;42(4):335-40.

Xiao Y, Li D, Chen L, Xu Y, Zhang D, Shao Y, et al. The R.I.R.S. scoring system: An innovative scoring system for predicting stone-free rate following retrograde intrarenal surgery. BMC Urol. 2017;17(1):105.

Perks AE, Schuler TD, Lee J, Ghiculete D, Chung DG, RJ DAH, et al. Stone attenuation and skin-to-stone distance on computed tomography predicts for stone fragmentation by shock wave lithotripsy. Urology. 2008;72(4):765-9.

Ghani KR, Wolf JS, Jr. What is the stone-free rate following flexible ureteroscopy for kidney stones? Nat Rev Urol. 2015;12(5):281-8.

Michel MS, Trojan L, Rassweiler JJ. Complications in percutaneous nephrolithotomy. Eur Urol. 2007;51(4):899-906; discussion

de la Rosette J, Assimos D, Desai M, Gutierrez J, Lingeman J, Scarpa R, et al. The Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study: indications, complications, and outcomes in 5803 patients. J Endourol. 2011;25(1):11-7.

Breda A, Ogunyemi O, Leppert JT, Lam JS, Schulam PG. Flexible ureteroscopy and laser lithotripsy for single intrarenal stones 2 cm or greater--is this the new frontier? J Urol. 2008;179(3):981-4.

Imamura Y, Kawamura K, Sazuka T, Sakamoto S, Imamoto T, Nihei N, et al. Development of a nomogram for predicting the stone-free rate after transurethral ureterolithotripsy using semi-rigid ureteroscope. Int J Urol. 2013;20(6):616-21.

Kanao K, Nakashima J, Nakagawa K, Asakura H, Miyajima A, Oya M, et al. Preoperative nomograms for predicting stone-free rate after extracorporeal shock wave lithotripsy. J Urol. 2006;176(4 Pt 1):1453-6; discussion 6-7.

Wu WJ, Okeke Z. Current clinical scoring systems of percutaneous nephrolithotomy outcomes. Nat Rev Urol. 2017;14(8):459-69.

Choo MS, Jeong CW, Jung JH, Lee SB, Jeong H, Son H, et al. External validation and evaluation of reliability and validity of the S-ReSC scoring system to predict stone-free status after percutaneous nephrolithotomy. PLoS One. 2014;9(1):e83628.

Ito H, Sakamaki K, Kawahara T, Terao H, Yasuda K, Kuroda S, et al. Development and internal validation of a nomogram for predicting stone-free status after flexible ureteroscopy for renal stones. BJU Int. 2015;115(3):446-51.

DOI: http://dx.doi.org/10.22037/uj.v0i0.5256


  • There are currently no refbacks.