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| ORIGINAL ARTICLE |
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| Year : 2022 | Volume
: 11
| Issue : 4 | Page : 336-343 |
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Comparative study between Guy's stone score, S.T.O.N.E nephrolithometry and Clinical Research Office of the Endourological Society (CROES) nephrolithometric nomogram in predicting stone-free rates in patients undergoing percutaneous nephrolithotomy: A prospective analysis
Saqib Shahab1, Ershad Hussain Galeti2, Mriganka Deuri Bharali3
1 Department of Surgery, RDJM Medical College, Muzaffarpur, Bihar, India
2 Department of Urology, Narayana Medical College, Nellore, Andhra Pradesh, India
3 Department of Urology, Dr. Pinnamaneni Siddhartha Institute of Medical Sciences, Andhra Pradesh, India
| Date of Submission | 12-Jan-2022 |
| Date of Decision | 14-Feb-2022 |
| Date of Acceptance | 21-Feb-2022 |
| Date of Web Publication | 17-Mar-2023 |
Correspondence Address:
Dr. Ershad Hussain Galeti
Department of Urology, Narayana Medical College, Nellore - 524 003, Andhra Pradesh
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jdrntruhs.jdrntruhs_42_22
Background: Several scoring systems have recently emerged to predict stone-free rates (SFRs) after percutaneous nephrolithotomy (PCNL). We aimed to compare the most commonly used scoring systems (Guy's stone score, STONE nephrolithometry and Clinical Research Office of the Endourological Society (CROES) nomogram) and assess their predictive accuracy for stone-free rates (SFRs). We also evaluated these scoring systems in their ability to predict perioperative complications, operative time (OT), length of hospital stay (LOH) and postoperative fall in haemoglobin.
Methods: We prospectively evaluated 50 consecutive patients with renal calculi who underwent PCNL at our institute for two years. Preoperative CT was done in all the patients. We applied GSS, STONE nephrolithometry and CROES nomogram in all patients. The association of these scoring systems with SFR, perioperative complications, OT, LOH and fall in haemoglobin was evaluated.
Results: The overall SFR in our study was 94%. The mean score of GSS, STONE and CROES was 1.66 ± 0.71, 7.08 ± 1.77 and 86.9 ± 4.35. GSS (AUC – 0.86) and S.T.O.N.E nephrolithometry (AUC – 0.837) score effectively predicted SFR, unlike CROES nomogram (AUC – 0.223). The overall complication rate was 54%. GSS (AUC – 0.643) and S.T.O.N.E nephrolithometry (AUC – 0.628) score effectively predicted post-operative complications, unlike CROES nomogram (AUC – 0.308). All three scoring systems (GSS, STONE and CROES) significantly correlated with OT (P < 0.01). None of the scoring systems correlated with LOH. GSS and CROES nomogram showed a weak correlation with fall in Hb.
Conclusion: GSS and STONE nephrolithometry effectively predicted SFR and perioperative complication, unlike the CROES nomogram. All scoring systems correlated with OT. Scoring systems did not correlate with LOH. GSS and CROES nomogram weakly correlated with fall in haemoglobin.
Keywords: Guy's score, percutaneous nephrolithotomy, renal stone, scoring system, STONE score
How to cite this article:
Shahab S, Galeti EH, Bharali MD. Comparative study between Guy's stone score, S.T.O.N.E nephrolithometry and Clinical Research Office of the Endourological Society (CROES) nephrolithometric nomogram in predicting stone-free rates in patients undergoing percutaneous nephrolithotomy: A prospective analysis. J NTR Univ Health Sci 2022;11:336-43 |
How to cite this URL:
Shahab S, Galeti EH, Bharali MD. Comparative study between Guy's stone score, S.T.O.N.E nephrolithometry and Clinical Research Office of the Endourological Society (CROES) nephrolithometric nomogram in predicting stone-free rates in patients undergoing percutaneous nephrolithotomy: A prospective analysis. J NTR Univ Health Sci [serial online] 2022 [cited 2023 Mar 21];11:336-43. Available from: https://www.jdrntruhs.org/text.asp?2022/11/4/336/371759 |
| Introduction | |  |
Nephrolithiasis is a very common condition, with elevated prevalence and recurrence, accounting for one of the most common diseases of the urinary tract. The stone disease almost affects about 5–15% of the world population, with a zenith incidence in younger adults between the third and fourth decade of life.[1],[2] Among the patients with renal stones, approximately 10–20% require surgical intervention.[3] In India, urinary stone disease constitutes a significant health burden throughout the country, especially in the Northwestern region, sometimes called 'The Stone Belt of India'.[4],[5] The goal of any renal stone surgical treatment is to achieve supreme stone clearance with minimum morbidity. Percutaneous nephrolithotomy (PCNL) remains the gold standard of many treatment options, especially for complex large renal stones.[6] The definition of success of PCNL is by 'stone-free rate' (SFR), which is to achieve the complete stone clearance. Several variables affect the post-operative outcome of PCNL, which include kidney anatomy, burden of stones, stone location, skeletal abnormalities and experience of the surgeon.[7] Despite the establishment of PCNL as one of the principal methods in treating renal stones, currently, there is no proper tool for predicting the success and complications associated with this treatment. This is very necessary because a scoring system could help to plan surgical strategies, predicting the success and complication rates, improvement in counselling of the patients and compare the outcomes between different institutions. Different scoring systems have been developed to predict the outcome of PCNL. Presently, three nomograms have been widely studied: Guy's Stone Score (GSS), STONE Nephrolithometry (STONE) and Clinical Research Office of the Endourological Society (CROES) nephrolithometric nomogram. CT scan is done preoperatively to determine the three scores. Post-operative stone-free status is assessed either by XRAY KUB or Non-contrast CT.[1] The GSS nomogram consists of parameters such as the number of stones, location of stone, any history of spina bifida or spine injury and association with any anatomical abnormality.
Based on these parameters, GSS is classified into four grades. The parameters used in the STONE score are – stone size (S), tract Length (T), obstruction (O), number of involved calyces (N) and essence or stone density (E). The CROES Nephrolithometric Nomogram uses variables such as stone burden, location of stone, prior treatment history, presence of staghorn stone, number of stones and case volume per year. The sum of the individual scores was used in predicting the stone-free status.[1] Our study is prospectively comparing the three widely used scoring systems GSS, STONE nephrolithometry and CROES nomogram in preoperatively predicting the SFR after PCNL. We are also evaluating the ability of these scoring systems in predicting perioperative complications, operative time (OT), fluoroscopy time (FT), length of hospital stay (LOH) and post-operative fall in haemoglobin.
Objective: To compare the GSS, STONE nephrolithometry and CROES nephrolithometric nomogram in predicting the SFRs after PCNL, and also to predict interrelation with post-operative complications, association with OT, haemoglobin fall, length of the hospital stay.
| Material and Methods | | |
This is a Prospective comparative study conducted in 50 patients with renal calculi more than 18 years of age who attended the urology OPD and underwent PCNL at our hospital over two years from April 2019 to March 2021. Exclusion criteria are age less than 18 years and more than 65 years, uncontrolled coagulopathy, patients with sepsis/uncontrolled DM/uncontrolled HTN and patients undergoing concomitant bilateral PCNL.
All the patients underwent preoperative routine blood and urine investigations. A non-contrast-enhanced computed tomography (NCCT) scan was performed preoperatively in all the patients. GSS, STONE nephrolithometry and CROES nomogram scores were calculated in all the patients. Post PCNL procedure, on post-op day 1, Complete blood counts, serum creatinine, serum electrolytes and XRAY KUB was done in all patients. Patients were discharged on the post-operative day 3 with DJ stent in situ.
All patients were followed up in the first week, second week and third week, and post-operative complications were noted on their visits to the hospital and treated accordingly. The complications were graded using a modified Clavien dindo score. Complications are classified as Clavien 3a, 3b, 4a, 4b and 5 were categorized as a major complication. A plain X-ray KUB and USG KUB were obtained at 4 weeks postop to evaluate any residual fragments and calculate SFR, and a DJ stent was removed at 4 weeks later.
Ethical clearance
Ethical approval of this study was provided by the Ethical Committee of Venkateshwara Kidney Centre, Karimnagar, Telangana, 505001, on 26-10-2018.
| Results | | |
The mean age of the patients in our study was 35.62 ± 10.57, with an age range between 18 and 58 years. Our study's number of male patients was 31, which accounts for 62% of the total patients in the study. The number of female patients in our study was 19, which accounts for 38% of the total patients in the study. A total of 15 (30%) patients had left-sided stones, whereas 35 (70%) patients had right-sided stones.
The mean GSS in the stone-free patients and non-stone free patients was 1.6 ± 0.681 and 2.67 ± 0.577, respectively. The mean STONE Score in stone-free patients and non-stone free patients was 6.96 ± 1.744 and 9 ± 1, respectively. The mean predictive success rate on CROES nephrolithometric nomogram in stone-free patients and non-stone free patients was 87.21 ± 4.232 and 83.33 ± 5.686. The difference between the two groups of patients was significant statistically for GSS, while the STONE score and CROES nomogram were not significant statistically [Table 1].
The mean age in stone-free patients and non-stone free patients was 35.82 ± 10.52 and 32 ± 13.11 years, respectively and not statistically significant.
SFR among males was 96.8% as compared to 89.5% in females and was not statistically significant.
SFR for left-sided stone was 100%, whereas the SFR for right-sided stone was 91.4%. The results were not statistically significant.
The mean stone burden in our study was 341.54 ± 200.82 mm2. Stone burden in stone-free patients was 327.26 ± 195.10 mm2, and in non-stone free patients was 565.33 ± 180.51 mm2. The stone burden was significantly associated with SFR.
The mean tract length was 86.56 ± 11.602. Tract length in stone-free patients and non-stone free patients was 87.32 ± 11.366 and 74.67 ± 10.066, respectively. It was not found to be statistically significant.
Moderate to severe obstruction was associated with an SFR of 90.90%, whereas patients with mild or no obstruction had an SFR of 100%. The result was not statistically significant.
Patients with single calyceal involvement had an SFR of 100%. SFR in patients with involvement of two or three calyces was 91.66% and 50%, respectively. Patients with Staghorn calculus had an SFR of 83.33%. This result was statistically significant, signifying that multiple calyceal involvement and staghorn calculus had poor SFR.
The mean essence of stones in our study was 921.32 ± 308.24. The essence in stone-free patients and non-stone free patients was 902.87 ± 80.87 and 1210.33 ± 80.87, respectively. The difference between the two groups was statistically not significant.
SFR for multiple stones and staghorn calculus was 86.66% and 83.33%, respectively. Stone located in a single calyx had 100% stone clearance rates. The result was not statistically significant.
Patients with abnormal renal anatomy had an SFR of 50% compared to 95.80% for patients with normal anatomy. The difference in end result between the two groups was not statistically significant.
Patients who previously underwent renal surgery to the ipsilateral renal unit did not show a statistically significant difference in SFR compared to those who had no such previous history.
About 27 (54%) patients had post-operative complications. Patients in our study experienced only minor complications (Clavien grades 1 and 2), and no significant complications were revealed. About 8 (16%) patients reported Clavien grade 1 complication, and 19 (38%) had Clavien grade 2 complication. The common complication reported was fever, which was seen in 14 (28%) patients. No grade 3, 4, 5 or intra-operative complications were noted in our study [Table 2].
A correlation coefficient was measured to assess the relationship between scoring systems (GSS, STONE score, CROES score) and perioperative complications. There was a positive and statistically significant correlation between GSS (r =0.37, P =0.04) and perioperative complications. There was a positive, weak and statistically significant correlation between S.T.O.N.E score (r =.36, P = <.01) and perioperative complications. There was no significant correlation between CROES score (r = −.22, P =.11) and perioperative complications. GSS and STONE scores significantly correlated with perioperative complications, whereas no significant correlation was seen between CROES score and perioperative complications [Table 3]. | Table 3: Correlation between Scoring Systems and Perioperative Complications
Click here to view |
The cutoff points calculated for perioperative complications for GSS, STONE and CROES score were 1.5, 6.5 and 89, respectively. The estimated AUC for GSS and STONE score was 0.643 and 0.628, respectively, demonstrating high predictive accuracy compared to 0.308 for CROES score. This suggests that both GSS and STONE score better predict perioperative complications and have higher predictive accuracy, whereas the CROES score is poor in predicting perioperative complications [Table 4]. | Table 4: Area Under Curve for Scoring Systems in Predicting Complications
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A correlation coefficient was measured to assess the relationship between scoring systems (GSS, STONE score, CROES score) and the OT. There was positive and statistically significant correlation between GSS (r =0.56, P = <.01) and OT. There was positive, strong and statistically significant correlation between S.T.O.N.E score (r =0.74, P = <.01) and OT. There was a negative, moderate and statistically significant correlation between CROES Score (r = −.60, P = <.01) and OT. All the scoring systems (GSS, STONE score, CROES score) were significantly correlated with the OT.
The mean OT in our study was 30.72 ± 12.45 minutes. OT in stone-free patients and non-stone free patients was 29.7 ± 12.03 minutes and 46.67 ± 8.08 minutes, respectively. The operative was significantly associated with SFR.
A correlation coefficient was computed to assess the relationship between scoring systems (GSS, STONE score, CROES score) and the LOH. There was no significant correlation between GSS (r =0.10, P =0.45) and LOH. There was no significant correlation between S.T.O.N.E score (r =.27, P =.055) and LOH. There no significant correlation between CROES score (r = −.14, P =.30) and LOH. The scoring systems (GSS, STONE score, CROES score) did not significantly correlate with the LOH. The mean LOH in our study was 3.06 ± 0.239 days. LOH in stone-free and non-stone free patients was 3.06 ± 0.247 and 3 ± 0, respectively. LOH was not significantly associated with SFR.
A correlation coefficient was computed to assess the relationship between scoring systems (GSS, STONE score, CROES score) and fall in Hb level. A positive and statistically significant correlation between GSS (r =0.33, P =0.01) and fall in Hb. There is no significant correlation between S.T.O.N.E score (r =.20, P =.15) and fall in Hb. A negative and statistically significant correlation between CROES score (r = −.32, P =.02) and fall in Hb. GSS and CROES score demonstrated a weak correlation with fall in Hb, whereas STONE score did not significantly correlate with fall in Hb. The mean fall in Hb in our study was 1.14 ± 0.46. The fall in Hb in stone-free patients and non-stone free patients was 1.10 ± 0.44 and 1.667 ± 0.45, respectively. The difference was not significant statistically.
| Discussion | | |
Various predictive tools have been developed to systematically and quantitatively assess the complexity of renal stones and predict outcomes after PCNL. The three most commonly used scoring systems GSS,[8] STONE nephrolithometry,[9] CROES nephrolithometric nomogram[10] have been evaluated in our study.
We prospectively studied 50 patients and calculated GSS, STONE score and CROES score in all patients. We evaluated these three scoring systems in their ability to predict SFR, post-operative complications, OT, length of the hospital stay (LOH) and post-op fall in haemoglobin.
The mean age of patients in our study was 35.62 ± 10.57 years, with an age range between 18 and 58 years. The mean age of patients in studies by Tailly[11] et al., Singla[12] et al., Sfoungaristos[13] et al. and Labadie[14] et al. was 55.8 ± 15.1, 41.9 ± 14.2, 55.6 ± 16.3 and 55.7 ± 14.9 years respectively. The mean age in our study was less than in other studies.
The sex distribution in our study consisted of 62% males and 38% females. The percentage of males/females reported by Singla[12] et al. and Sfoungaristos[13] et al. was 62.5%/37.5% and 64.4% and 35.6%, respectively, which was quite similar to our study.
In our study, 30% of patients had left-sided stones, whereas 60% had right-sided stones. Studies by Singla[12] et al. and Labadie[14] et al. also reported predominantly right-sided stone. However, Tailly[11] et al. and Sfoungaristos[13] et al. reported left-sided stones predominantly.
The overall SFR in our study was 94%. Out of the 50 patients in our study, 47 were stone free, whereas three patients had residual stones and required auxiliary procedure.
Tailly[11] et al. retrospectively reviewed 586 patients and reported an SFR of 67.4%. Singla[12] et al. studied 48 patients prospectively and reported an SFR of 62.2%, and Sfoungaristos[13] et al. reviewed 73 patients with staghorn calculi only and reported an SFR of 65.8%. The SFR in our study was higher than other comparative studies that were reviewed.
Mean scores in our study were as follows – GSS 1.6 ± 0.68, STONE score 6.96 ± 1.74 and CROES nomogram (predictive success rate in %) 87.21 ± 4.23. The mean scores of the three scoring systems in other studies are listed in [Table 5]. Our study's mean GSS and STONE score was lower than other studies, whereas the mean CROES score was higher. This could be a reason for the higher SFR in our study as compared to other studies. The mean scores in stone free patients and non stone free patients in various studies compared to our study are listed. The mean GSS and STONE score in our study was lower in stone free patients than non stone free patients. The CROES score was higher in stone free patients as compared to the non stone free patients. These findings were comparable to other studies.[11],[12],[13],[14] | Table 5 : The Mean Scores in Stone Free and Non Stone Free Patients in Various Studies as Compared to Our Study
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To identify the accuracy of the scoring systems, we generated an area under the curve (AUC) analysis. AUC of GSS, STONE score and CROES score were 0.86, 0.837 and 0.223, respectively in our study. GSS and STONE score were effective and reliable in predicting SFR and have higher predictive accuracy, whereas CROES had a poor predictive accuracy for SFR. One reason for the CROES score's poor predictive accuracy was the higher case volume per year at our institute. Therefore, our mean CROES score was higher than other studies. AUC for GSS, STONE and CROES score for various studies is listed in [Table 6]. Vicentini[1] et al., Singla[12] et al. and Labadie[14] et al. concluded that GSS, STONE and CROES scores equally and effectively predicted SFR. Sfoungaristos[13] et al. concluded that the STONE score had higher predictive accuracy than GSS and CROES. Noureldin[15] et al. compared GSS and STONE score and reported AUC of 0.74 and 0.63. They concluded that both GSS and STONE scoring systems have comparative accuracies in predicting post-PCNL stone-free status.
The mean stone burden in our study was 341.54 ± 200.82 mm2. Stone burden in stone-free patients was 327.26 ± 195.10 mm2, and in non-stone free patients was 565.33 ± 180.51 mm2. The stone burden was significantly associated with SFR in our study. Tailly[11] et al. reported a mean stone burden of 557 mm2 and 1045 mm2 in stone-free patients and non-stone-free patients, respectively and reported that stone burden was significantly associated with SFR. Singla[12] et al. reported a mean stone burden in stone-free patients as 283 mm2, which was significantly lower than non-stone-free patients.
The mean tract length in our study was 86.56 ± 11.602 mm. Tract length in stone-free patients and non-stone free patients was 87.32 ± 11.366 mm and 74.67 ± 10.066 mm, respectively and was not statistically significant. Tailly[11] et al. and Singla[12] et al. also reported that tract length was not significantly associated with SFR.
In our study, there was no significant difference between the degree of obstruction and stone-free status. However, studies by Tailly[11] et al. and Singla[12] et al. reported that moderate to severe HDN was significantly associated with a poorer SFR.
Multiple calyceal stones and staghorn calculus had poor SFR as compared to single calyceal involvement in our study. Tailly[11] et al. and Singla[12] et al. also reported poor SFR for multiple calyceal stones.
The mean essence of stones in our study was 921.32 ± 308.24 HU. The essence in stone-free and non-stone free patients was 902.87 ± 80.87 HU and 1210.33 ± 80.87 HU, respectively. The difference between the two groups was not significant statistically. Labadie[14] et al., Tailly[11] et al., Singla[12] et al. also reported that Stone essence was not associated significantly with stone-free status.
The complications were graded using a modified Clavien score. In our study, 27 (54%) patients developed complications. Patients experienced only minor complications (Clavien grade 1 and 2), and no significant complications were reported in our study. About 8 (16%) patients reported Clavien grade 1 complication, and 19 (38%) had Clavien grade 2 complication. The most common complication reported was fever, which was seen in 14 (28%) patients. No Clavien grade 3, 4 or 5 complications were seen. None of the patients in our study reported any intra-operative complications.
To recognize the predictive accuracy of the scoring systems, we generated an AUC analysis. In our study, the estimated AUC for GSS was 0.643, and the STONE score was 0.628 demonstrating high predictive accuracy compared to 0.308 for the CROES score. This suggests that GSS and STONE score effectively predict perioperative complications, whereas CROES score is poor in predicting perioperative complications. Correlation tables also revealed significant correlation of perioperative complications with GSS (r =0.37, P =0.04) and S.T.O.N.E score (r =.36, P = <.01). However no significant correlation was seen between CROES score (r = −.22, P =.11) and perioperative complications.
Tailly[11] et al. reported a complication rate of 29.3%, with only 3.5% complications of Clavien grade 3 or higher grade. They concluded that neither of the scoring systems was strong predictor of complications.
Sfoungaristos[13] et al. reported an overall complication rate of 21%. Grade 1, 2, 3 and 4 complications were seen in 21%, 15.1%, 2% and 2% patients, respectively. They reported that none of the scoring systems was significantly associated with post-operative complications (p > 0.05). Bibi[16] et al. reported that out of the three scoring systems, the only STONE score was a significant predictor of complications.
The mean OT in our study was 30.72 ± 12.45 minutes. OT in stone-free and non-stone free patients was 29.7 ± 12.03 minutes and 46.67 ± 8.08 minutes, respectively. OT was significantly associated with SFR. A correlation table was computed and it was found that all three scoring systems significantly correlated with OT. GSS (r =0.56, P = <.01) and S.T.O.N.E score (r =0.74, P = <.01) showed positive and significant correlation, whereas CROES score (r = −.60, P = <.01) showed negative but significant correlation, suggesting that higher CROES score is associated with shorter OTs.
Tailly[11] et al. reported that SFR was significantly associated with OT. They also reported that on multivariable linear regression analysis, the only STONE score was a significant predictor of long OT. Labadie[14] et al. and Singla[12] et al. also found a significant correlation between SFR and OT. However, they did not assess the relationship of the three scoring systems with OT. The mean LOH in our study was 3.06 ± 0.239 days. LOH was not associated significantly with SFR. Correlation table was computed and no significant correlation was seen between the three scoring systems and LOH [GSS (r =0.10, P =0.45), S.T.O.N.E score (r =.27, P =.055) and CROES score (r = −.14, P =.30)].
Tailly[11] et al. reported a mean LOH of 3.2 ± 2.4 in their study. There was no significant association between LOH and SFR. They reported that none of the scoring systems independently predicted SFR. Labadie[14] et al. reported that LOH was not significantly associated with SFR. Guy's score and STONE score were associated with LOH (p = 0.03, P = 0.009, respectively). However, the CROES nomogram was not predictive of LOH.
Fall in Hb in our study was used as a surrogate marker for blood loss. The mean fall in Hb in our study was 1.14 ± 0.46 g%. The fall in Hb in stone-free and non-stone free patients was 1.10 ± 0.44 and 1.667 ± 0.45, respectively. The difference was not statistically significant. Correlation tables were computed. GSS (r =0.33, P =0.01) and CROES score (r = −.32, P =.02) showed weak but significant correlation with postoperative fall in Hb. S.T.O.N.E score (r =.20, P =.15) did not correlate with postoperative fall in Hb. Labadie[14] et al. reported that GSS (p < 0.01) and S.T.O.N.E score (p = 0.03) were significantly associated with EBL. However, the CROES score was not predictive of EBL.
| Conclusion | | |
GSS and STONE nephrolithometry are effective in predicting SFR and perioperative complications. Hence, they can be used as a preoperative scoring system to predict the outcome of PCNL. This would improve surgical planning and patient counselling. However, further research with a larger sample size is required to extrapolate these findings to the general population.
Abbreviations
PCNL – percutaneous nephrolithotomy; GSS – Guy's Stone Score; SFR – Stone free rate; OT – operative time; LOH – length of hospital stay; NCCT – non-contrast computed tomography; EBL – estimated blood loss; AUC – area under the curve; HU – Hounsfield Unit
Consent to publish and participate
Taken from all the participants
Acknowledgements
We extend their sincere thanks to all the patients who participated in the study
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Vicentini FC, Serzedello FR, Thomas K, Marchini GS, Torricelli FC, Srougi M, et al. What is the quickest scoring system to predict percutaneous nephrolithotomy outcomes? A comparative study among S.T.O.N.E score, Guy's Stone Score and CROES nomogram. Int Braz J Urol 2017;43:1102–9.  |
| 2. | Moe OW. Kidney stones: Pathophysiology and medical management. Lancet 2006;367:333–44. |
| 3. | Olbert PJ, Hegele A, Schrader AJ, Scherag A, Hofmann R. Pre- and perioperative predictors of short-term clinical outcomes in patients undergoing percutaneous nephrolitholapaxy. Urol Res 2007;35:225–30. |
| 4. | Bhat A, Singh V, Bhat M, Kumar V, Bhat A. Spectrum of urinary stone composition in Northwestern Rajasthan using Fourier transform infrared spectroscopy. Indian J Urol 2018;34:144-8. [ PUBMED] [Full text] |
| 5. | Guha M, Banerjee H, Mitra P, Das M. The demographic diversity of food intake and prevalence of kidney stone diseases in the Indian continent. Foods 2019;81:37. |
| 6. | 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;173:1991–2000. |
| 7. | Michel MS, Trojan L, Rassweiler JJ. Complications in percutaneous nephrolithotomy. Eur Urol 2007;51:899–906. |
| 8. | Thomas K, Smith NC, Hegarty N, Glass JM. The Guy's stone score—Grading the complexity of percutaneous nephrolithotomy procedures. Urology 2011;78:277–81. |
| 9. | Sharma K, Goel A, Gupta S. Re: Okhunov et al.: S.T.O.N.E. Nephrolithometry: Novel surgical classification system for kidney calculi (Urology 2013;81:1154–1160). Urology 2013;82:979. |
| 10. | 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;190:149–56. |
| 11. | 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;30:594–601. |
| 12. | Singla A, Khattar N, Nayyar R, Mehra S, Goel H, Sood R. How practical is the application of percutaneous nephrolithotomy scoring systems? Prospective study comparing Guy's Stone Score, S.T.O.N.E. score and the Clinical Research Office of the Endourological Society (CROES) nomogram. Arab J Urol 2017;15:7–16. |
| 13. | Sfoungaristos S, Gofrit ON, Pode D, Landau EH, Duvdevani M. Percutaneous nephrolithotomy for staghorn stones: Which nomogram can better predict postoperative outcomes? World J Urol 2015;34:1163–8. |
| 14. | Labadie K, Okhunov Z, Akhavein A, Moreira DM, Moreno-Palacios J, del Junco M, et al. Evaluation and comparison of urolithiasis scoring systems used in percutaneous kidney stone surgery. J Urol 2015;193:154–9. |
| 15. | 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 post-percutaneous nephrolithotomy. World J Urol 2015;33:1821–5. |
| 16. | Bibi M, Sellami A, Ouanes Y, Chaker K, Ben Rhouma S, Nouira Y. Nephrolithometry scoring systems in percutaneous nephrolithotomy: The Guy's stone score, S.T.O.N.E. nephrolithometry, CROES nomogram and S-ReSC score. Eur Urol Suppl 2018;17:e1213. |
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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