Stone-scoring systems for predicting complications in percutaneous nephrolithotomy: A systematic review of the literature

doi:10.1016/j.ajur.2023.01.005

Asian Journal of Urology, 2023, 10 (3): 226-238 doi: 10.1016/j.ajur.2023.01.005

Review

Stone-scoring systems for predicting complications in percutaneous nephrolithotomy: A systematic review of the literature

Giorgio Mazzon^a,*(

),Simon Choong^b,Antonio Celia^a

^a Department of Urology, AULSS7 Pedemontana, San Bassiano Hospital, Bassano Del Grappa, Italy
^b Institute of Urology, University College Hospitals of London, London, UK

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Abstract

Objective Percutaneous nephrolithotomy is a treatment of choice for larger stones of the upper urinary tract. Currently, several nephrolithometric nomograms for prediction of post-operative surgical outcomes have been proposed, although uncertainties still exist regarding their roles in the estimation of complications.
Methods We conducted a systematic review on PubMed and Web of Sciences databases including English studies with at least 100 cases and published between January 2010 and December 2021. We identified original articles evaluating correlations between the Guy's stone score, the stone size (S), tract length (T), obstruction (O), number of involved calices (N), and essence or stone density (E) (S.T.O.N.E.), Clinical Research Office of the Endourological Society (CROES), and Seoul National University Renal Stone Complexity (S-ReSC) scores and post-operative complications in adult patients. We also included newly designed nomograms for prediction of specific complications.
Results After an initial search of 549 abstracts, we finally included a total of 18 papers. Of them, 11 investigated traditional nephrolithometric nomograms, while seven newly designed nomograms were used to predict specific complications. Overall, 7316 patients have been involved. In total, 14 out of 18 papers are derived from retrospective single-center studies. Guy's stone score obtained correlation with complications in five, S.T.O.N.E. nephrolithometry score in four, while CROES score and S-ReSC score in three and two, respectively. None of the studies investigated minimally invasive percutaneous nephrolithotomy (PCNL) and all cases have been conducted in prone position. Considering newly designed nomograms, none of them is currently externally validated; five of them predict post-operative infections; the remaining two have been designed for thromboembolic events and urinary leakage.
Conclusion This review presents all nomograms currently available in the PCNL field and highlights a certain number of concerns. Published data have appeared contradictory; more recent tools for prediction of post-operative complications are frequently based on small retrospective cohorts and lack external validations. Heterogeneity among studies has also been noticed. More rigorous validations are advisable in the future, involving larger prospective patients’ series and with the comparison of different tools.

Key words： Percutaneous nephrolithotomy Complications Nomogram Stone-scoring system Clavien-Dindo

Received: 22 December 2022 Available online:

Corresponding Authors: Giorgio Mazzon E-mail: giorgiomazzon83@gmail.com

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Giorgio Mazzon,Simon Choong,Antonio Celia. Stone-scoring systems for predicting complications in percutaneous nephrolithotomy: A systematic review of the literature[J]. Asian Journal of Urology, 2023, 10(3): 226-238.

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http://www.ajurology.com/EN/10.1016/j.ajur.2023.01.005 OR http://www.ajurology.com/EN/Y2023/V10/I3/226

The systematic review's flowchart.

Study	Nomogram name if available and investigated endpoints^a	Included variable	Externally validated	Method for calculation
Thomas et al. [8]	Guy’s stone score; SFR	·? Grade I: a solitary stone in the mid-lower pole, or renal pelvis with simple anatomy ·? Grade II: a solitary stone in the upper pole with simple anatomy, multiple stones in a patient with simple anatomy, or any solitary stone in a patient with abnormal anatomy ·? Grade III: multiple stones in a patient with abnormal anatomy, stones in a calyceal diverticulum, or partial staghorn calculus ·? Grade IV: staghorn calculus or any stone in a patient with spina bifida or spinal injury	Yes	Computed tomography imaging
Okhunov et al. [9]	S.T.O.N.E. nephrolithometry score; SFR	·? S.T.O.N.E.	Yes	Graphic chart
Smith et al. [10]	CROES score; SFR	·? Stone burden, stone location, number of stones, and surgical volume	Yes	Graphic chart
Jeong et al. [11]	S-ReSC; SFR	·? Pelvi-caliceal system subdivided in nine separate locations, each location corresponding to 1 point ·? Total score: cumulative sum of involved locations	Yes	Computed tomography imaging
Xun et al. [24]	Urosepsis in general population	·? Albumin-globulin ratio, leukocytosis, positive urine culture, and female sex	No	Graphic chart
Jiang et al. [25]	Post-operative fever, SIRS, sepsis in general population	·? Post-operative fever: leukocyturia and urine nitrite ·? SIRS: positive urine culture, positive urine nitrite, and operation time ·? Sepsis: positive urine nitrites, urine pH, positive urine culture, serum calcium, and operation time	No	Computer software and graphic chart
Wang et al. [26]	Urosepsis in general population	·? Presence of staghorn stone, pre-operative urine culture, and pre-operative nephrostomy	No	Graphic chart
Gu et al. [28]	Urosepsis in general population	·? Presence of urine nitrite, positive urine culture, intra-operative hypotension, and staghorn stone	No	Graphic chart
Liu et al. [27]	Urosepsis in general population	·? White blood cell count, presence of urine nitrites, positive urine culture, staghorn stone, and complete stone clearance	No	Graphic chart
Zeng et al. [29]	Venous thromboembolism	·? Discontinued anticoagulant or antiplatelet therapies, increased D-dimer, hydronephrosis, higher Caprini RAM score, post-operative sepsis-shock	No	Graphic chart
Sahan et al. [30]	Urinary leakage	·? Hydronephrosis grade, parenchymal thickness, and nephroscopy time	No	Graphic chart

Currently available nomograms applicable in percutaneous nephrolithotomy.

Study	Country	Study design	Study period	Participant variable	Used technique	Analyzed complication	Key result
Ozgor et al. [12]	Turkey	Retrospective, single-center study	2008-2016	·? 248 obese patients with renal stones ·? Pre-operative imaging: CT ·? Patients with preliminary percutaneous nephrostomy excluded ·? Investigated nomograms: GSS, S.T.O.N.E. nephrolithometry score, and CROES score	30 Fr prone PCNL and 26 Fr nephroscope	Post-operative complications according to CD system [13]	·? Overall 57 patients had complications: 21 patients had CD 1; 17 had CD 2; 13 had CD 3a; three had CD 3b; and three had CD 4a
Tailly et al. [14]	Canada, Belgium, and the United States	Retrospective, multi-center study	2006-2013	·? 586 patients with renal stones ·? Pre-operative imaging: CT ·? Secondary procedures excluded ·? Investigated nomograms: GSS, S.T.O.N.E. nephrolithometry score, and CROES score	Unspecified	Post-operative complications according to CD system	·? Complication rate was 29.2%, and CD 3 or higher was 3.4%
Farhan et al. [15]	Pakistan	Prospective, single-center study	2014	·? 107 patients with radio-opaque renal stones ·? Pre-operative imaging: CT ·? Patients with indwelled nephrostomy or ureteric stent, previous ipsilateral surgery for stones and radiolucent stones excluded ·? Investigated nomogram: S.T.O.N.E. nephrolithometry score	Single-tract standard prone PCNL (tract size not mentioned), dilatation carried out with Alken dilators, and stone fragmentation obtained with ultrasonic-ballistic device	Post-operative complications according to CD system	·? 22 (20.8%) patients had complications: one patient had CD 1, 11 had CD 2, seven had CD 3a, and three had CD 3b
Yarimoglu et al. [16]	Turkey	Retrospective, single-center study	2012-2015	·? 262 patients with renal stones ·? Pre-operative imaging: CT ·? Investigated nomograms: S.T.O.N.E. nephrolithometry score and CROES score	Prone PCNL, unspecified the track diameter: 14 Fr nephrostomy tube placed at completion of case	Post-operative complications according to CD system and EBL	·? 89 patients had post-operative complications: 41 (15.6%) patients had CD 1; 35 (13.4%) had CD 2; 5 (1.9%) had CD 3a; and 8 (3.1%) had CD 3b.
Yarimoglu et al. [17]	Turkey	Retrospective, single-center study	2012-2015	·? 506 patients with renal stones ·? Pre-operative imaging: CT ·? Investigated nomograms: GSS, S.T.O.N.E. nephrolithometry score, CROES score, and S-ReSC score	Prone standard PCNL, unspecified the track diameter: 14 Fr nephrostomy tube placed at completion	Post-operative complications according to CD classification system and EBL	·? 159 patients had post-operative complications: 70 (13.8%) patients had CD 1; 57 (11.2%) had CD 2; 27 (5.3%) had CD 3a; and 5 (0.98%) had CD 3b
Biswas et al. [18]	India	Prospective, single-center study	2017-2019	·? 252 patients with renal stones ·? Pre-operative imaging: CT ·? Second stage PCNL excluded or with pre-operative percutaneous nephrostomy or double-J stent ·? Investigated nomograms: GSS, S.T.O.N.E. nephrolithometry score, and CROES score	Single stage more than 26 Fr prone PCNL, lithotripsy carried out with ultrasonic and ballistic device: routinely a 20 Fr percutaneous drainage placed at completion	Intra-operative complications, post-operative complications according to CD classification system and EBL	·? 120 (48%) patients had complications: CD 1 was 33% ·? Mean EBL was 1.4-2.0 g/dL in stone-free group while it was 2.0 g/dL in non-stone-free group
Labadie et al. [19]	The United States	Retrospective, multi-center study	2009-2012	·? 246 patients with unilateral renal stone ·? Pre-operative imaging: CT ·? Exclusion criteria: patients with history of prior surgery on same kidney and those with indwelled percutaneous nephrostomy or double-J stent ·? Investigated nomograms: GSS, S.T.O.N.E. nephrolithometry score, and CROES score	Standard PCNL	Intra-operative complications and post-operative complications within 30 days according to CD classification system and EBL	·? 42 (17%) patients had post-operative complications: CD 1 was 23; CD 2 was 8; CD 3a was 5; CD 3b was 3; and CD 4a was 3
Choi et al. [20]	The Republic of Korea	Retrospective, single-center study	2003-2014	·? 217 patients with staghorn stones and available CT imaging pre-operatively ·? Investigated nomograms: GSS, S.T.O.N.E. nephrolithometry score, and CROES score	24-30 Fr prone PCNL, lithotripsy with ultrasonic-ballistic device: 20 Fr nephrostomy tube and/or double-J stent at completion	Post-operative complications according to CD classification system	·? 71 patients had complications: 45 were minor (CD 1-2) and 26 were major (CD 3a-5)
Choi et al. [21]	The Republic of Korea	Retrospective, single-center study	2012-2015	·? 141 patients with unilateral renal stones ·? Pre-operative imaging: CT ·? Exclusion criteria: bilateral simultaneous PCNL, more than three tracks PCNL, and serious intra-operative bleeding or perforation of collecting system ·? Investigated nomograms: GSS, S.T.O.N.E. nephrolithometry score, and CROES score	24 Fr tubeless prone PCNL	Post-operative complications according to CD classification system	·? 36 (25.5%) complications registered in 24 (17.0%) patients: CD I was 9 (6.4%); CD 2 was 11 (7.8%); CD 3a was 8 (5.7%); CD 3b was 3 (2.1%); CD 4a was 1 (0.7%); CD 4b was 3 (2.1%); and CD 5 was 1 (0.7%)
Al Adl et al. [22]	Egypt	Prospective, single-center Study	2015-2018	·? 166 patients with renal stones ·? Pre-operative imaging: CT ·? Patients with preliminary percutaneous nephrostomy or double-J stent excluded ·? Investigated nomograms: GSS, S.T.O.N.E. nephrolithometry score, CROES score, and S-ReSC score	Single stage standard PCNL	Post-operative complications according to CD system	·? 14 (8.4%) patients had CD 1; 26 (15.7%) had CD 2; 5 (3.1%) had CD 3a; and 5 (3.0%) had CD 3b
Khan et al. [23]	Pakistan	Prospective, single-center study	2015-2017	·? 190 patients with unilateral radio-opaque renal stones ·? Exclusion criteria: radiolucent and bilateral stones, previous ipsilateral surgery for stones, blood clotting disorders, and urinary tract infections	Single tract 26 Fr prone PCNL: 24 Fr nephroscope, lithotripsy with ultrasonic-ballistic device	Post-operative complications according to CD system	·? 24 patients (12.6%) had post-operative complications: CD 1-2 were 16 ·? Six patients required blood-transfusion; ·? One patient had angioembolization

The list and main characteristics of studies evaluating correlations between complications and traditional nephrolithometric nomograms.

Study	Country	Study design	Study period	Participant variable	Used technique	Analyzed complication	Key result
Xun et al. [24]	China	Retrospective, single-center study	2012-2018	·? 745 patients treated for unilateral solitary ureteric stone larger than 10 mm in diameter ·? Patients with abnormal anatomy excluded ·? Pre-operative imaging: NCCT	·? Not clarified	·? Sepsis defined according to 2001 International Sepsis Definitions Conference	·? 35 (4.7%) patients had post-PCNL sepsis ·? Unclear whether internally validated
Jiang et al. [25]	China	Retrospective, single-center study	2016-2017	·? 969 patients treated for renal stones ·? Patients with pre-operative fever excluded ·? Not mentioned other inclusion or exclusion criteria ·? Pre-operative imaging: unclear whether all patients received CT imaging ·? Inflammatory markers not included as well as whether patients were pre-stented	·? 18-24 Fr PCNL, not specified the patients’ position ·? High-power Ho:YAG laser lithotripsy in all cases	·? Post-operative fever defined as temperature over 38°C ·? Post-operative SIRS defined according to Society of Critical Care Medicine in 2001 ·? Sepsis defined using qSOFA criteria	·? 216 (22.3%) patients had fever; 166 (17.1%) had SIRS; and 25 (2.6%) had urosepsis ·? Unclear whether internally validated
Wang et al. [26]	China	Retrospective, single-center study	2017-2019	·? 246 patients included with either renal or upper ureteric stones ·? Unclear how staghorn stones have been defined ·? Exclusion criteria: pre-existing neoplasms, urinary tract tuberculosis, incomplete medical records ·? Unclear pre-operative imaging ·? Pre-operative inflammatory markers not presented	·? 22-24 Fr prone PCNL, 17-22 Fr nephroscope, lithotripsy carried out with either high-power Ho-YAG laser or ultrasonic lithotripsy ·? All patients had percutaneous nephrostomy and a 5 Fr double-J stent at completion	·? Post-operative sepsis defined according to qSOFA criteria	·? 15 (6.1%) patients developed post-operative sepsis ·? Internally validated
Gu et al. [28]	China	Retrospective, single-center study	2010-2020	·? 366 diabetic patients (diagnosed with 2-h 75 g post-load plasma glucose level, oral glucose tolerance test, or fasting plasma glucose) with renal stones ·? Urosepsis defined using SIRS criteria (two or more criteria)	·? One-stage 24 Fr prone PCNL ·? All patients had both double-J stent and percutaneous nephrostomy inserted	·? Urosepsis within 24 h from surgery	·? 71 out of 366 (19.4%) patients had post-operative urosepsis ·? Unclear if internally validated
Liu et al. [27]	China	Retrospective, single-center study	2012-2019	·? 241 diabetic patients (diagnosed with 2-h 75 g postload plasma glucose level, oral glucose tolerance test, or fasting plasma glucose) with renal stones ·? Infectious events diagnosed using SIRS criteria	·? One-stage 24 Fr prone PCNL under spinal anesthesia	·? Urosepsis within 24 h from surgery	·? Urosepsis occurred in 41 (17.0%) patients, all within 24 h from surgery ·? Internally validated
Zeng et al. [29]	China	Retrospective, single-center study	2018-2020	·? 896 adult patients ·? Patients with tachycardia or chest pain were suspected for PE and undergone CT angiogram of the chest or ventilation-perfusion lung scan ·? Patients with increased D-dimer or Caprini RAM score received a lower limb Doppler scan	·? Not clarified	·? Cumulative risk of DVT and PE	·? Overall risk was 2.8% (25 patients) ·? 1 out of 25 patients experienced PE while the others had DVT only ·? Unclear if internally validated
Sahan et al. [30]	Turkey	Retrospective, single-center study	2011-2020	·? 932 patients included ·? Urine leakage if persisting for more than 24 h post-operatively ·? Patient stented post-operatively excluded	·? 26 Fr prone PCNL, 14 Fr percutaneous nephrostomy tube placed in all cases	·? Urinary leakage	·? Risk of urine leakage was 9.9% ·? Patients stratified in low-, moderate- and high-risk of complication ·? Internally validated

The list and main characteristics of studies evaluating newly designed nomograms for prediction of complications.

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[22]	Al Adl AM, Mohey A, Abdel Aal A, Abu-Elnasr HAF, El Karamany T, Noureldin YA. Percutaneous nephrolithotomy outcomes based on S.T.O.N.E., GUY, CROES, and S-ReSC scoring systems: the first prospective study. J Endourol 2020; 34:1223-8. doi: 10.1089/end.2019.0856
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[27]	Liu J, Yang Q, Lan J, Hong Y, Huang X, Yang B. Risk factors and prediction model of urosepsis in patients with diabetes after percutaneous nephrolithotomy. BMC Urol 2021; 21:74. https://doi.org/10.1186/s12894-021-00799-3. doi: 10.1186/s12894-021-00799-3 pmid: 33910537
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[29]	Zeng H, Gao M, Chen J, Cui Y, Huang F, Zeng F, et al. Incidence and risk factors of venous thromboembolism after percutaneous nephrolithotomy: a single-center experience. World J Urol 2021; 39:3571-7. doi: 10.1007/s00345-021-03658-w pmid: 33725149
[30]	Sahan M, Yarimoglu S, Polat S, Nart B, Koras O, Bozkurt IH, et al. A novel nomogram and a simple scoring system for urinary leakage after percutaneous nephrolithotomy. Int Braz J Urol 2022; 48:817-27. doi: 10.1590/S1677-5538.IBJU.2022.0091 pmid: 35839435
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[33]	Zeng G, Cai C, Duan X, Xu X, Mao H, Li X, et al. Mini percutaneous nephrolithotomy is a noninferior modality to standard percutaneous nephrolithotomy for the management of 20 mme40 mm renal calculi: a multicenter randomized controlled trial. Eur Urol 2021;79:114-21.
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[35]	Jiang K, Sun F, Zhu J, Luo G, Zhang P, Ban Y, et al. Evaluation of three stone-scoring systems for predicting SFR and complications after percutaneous nephrolithotomy: a systematic review and meta-analysis. BMC Urol 2019; 19:57. https://doi.org/10.1186/s12894-019-0488-y. doi: 10.1186/s12894-019-0488-y pmid: 31262284
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