All relevant data are within the paper and its Supporting Information files.

Introduction {#sec005}
============

The prevalence and incidence of renal and ureteral lithiasis are increasing worldwide \[[@pone.0237068.ref001], [@pone.0237068.ref002]\]. Surgical treatments are evolving and flexible ureterorenoscopy (f-URS) has been shown to outperform extracorporeal shockwave lithotripsy (ESWL) and percutaneous nephrolithotomy (PCNL) in a number of indications \[[@pone.0237068.ref003], [@pone.0237068.ref004]\]. This depends mainly on the size, number and location of the stones. ESWL is a minimally invasive technique but often requires several procedures. PCNL seems to be the most successful but is the most invasive procedure \[[@pone.0237068.ref005]\]. f-URS also gives excellent results and is associated with a low complication rate \[[@pone.0237068.ref006]\]. Furthermore, f-URS is a safe and efficient option in specific populations such as obese patients \[[@pone.0237068.ref007]\].

Many studies have evaluated the factors affecting the success rate of these procedures. Preoperative scores and nomograms have been developed and are available to predict the stone-free rate (SFR) with varying degrees of accuracy. Several factors affecting the outcome of ESWL and PCNL have been described and nomograms have been established \[[@pone.0237068.ref008]--[@pone.0237068.ref011]\].

For f-URS, four scores have been developed. Two of these have been compared and validated in different cohorts: the Resolu Unsal Stone Score (RUSS) and modified Seoul National University Renal Stone Complexity (S-ReSC) score \[[@pone.0237068.ref012], [@pone.0237068.ref013]\]. To our knowledge, the other two scores, the S.T.O.N.E score described by Molina et al. \[[@pone.0237068.ref014]\] and Ito's nomogram \[[@pone.0237068.ref015]\] have not been validated in any other cohorts.

Our aim was to evaluate these four scores in a large group of patients with renal and ureteral stones treated by f-URS and holmium fragmentation.

Materials and methods {#sec006}
=====================

Study population {#sec007}
----------------

This large retrospective study evaluated all f-URS procedures for upper urinary tract calculi performed in our institution between January 2009 and December 2016. A total of 1011 consecutive procedures were recorded: 211 were excluded from the study due to lack of preoperative imaging and insufficient post-operative follow-up. Thus 800 procedures were analysed. The S.T.O.N.E score analysis was performed on the entire cohort ('ureteral and renal' group (UR): 800 procedures). The other three scores were developed for the renal stone only. They were analysed in the subgroup of patients with renal stones only ('renal only' group (RO): 669 procedures).

Surgical procedures {#sec008}
-------------------

f-URS was performed by several experienced surgeons following a single standardized protocol. All details of the surgical procedure have been described previously \[[@pone.0237068.ref016]\]. Briefly, all procedures were performed under general anaesthesia. Patients were installed in the lithotomy position (with the leg on the treated side in semi-extension to straighten the ureter). The procedure began with rigid cystoscopy to insert a stiff guidewire up to the kidney. Ureteral dilation and an access sheath were used when necessary (mainly 12F/14F, Cook Medical^®^, Bloomington, IN, USA; or 11/13 F, Boston Scientific^®^, Natick, MA, USA) and were placed under radioscopic guidance. An irrigation pressurizing system was used routinely. Flexible ureteroscopes were Flex-X2TM, Storz^®^; Tuttlingen, Germany, or Olympus URF-V; Olympus^®^, Tokyo, Japan. Stones were fragmented with a holmium:YAG laser (272 or 365l m fibres). Once fragmentation was completed, the fragments were extracted with different nitinol stone baskets. After stone removal, a double pigtail indwelling ureteral stent (7F) was placed at the surgeon's discretion.

Preoperative and postoperative evaluation {#sec009}
-----------------------------------------

The following data were recorded: epidemiological characteristics (age, gender, body mass index (BMI), medical treatment, medical history), characteristics of the stones (localization, size, density, composition), surgical treatment (duration of the procedure, ureteral dilation, ureteral access sheath (UAS)), surgical and anaesthesia complications according to the Clavien-Dindo classification \[[@pone.0237068.ref017]\]. All patients included were evaluated by performing a preoperative computed tomography (CT) scan.

Score analysis {#sec010}
--------------

### S.T.O.N.E. score {#sec011}

The S.T.O.N.E score was calculated using five parameters: S: size of stone; T: topography or location; O: obstruction; N: number of stone(s); E: evaluation of Hounsfield Units (HU). Each variable is graded from 1 to 3 and the grades are added to give a final score (5 to 15 points). A high total score is predictive of a failure f-URS outcome.

### RUSS score {#sec012}

The RUSS score considers four parameters (1 point for each of the four criteria): stone size \>20 mm; lower pole location with infundibulopelvic angle (IPA) \<45°; stone number in different calyces \>1; abnormal renal anatomy; with a total score ranging from 0 to 4.

### Modified ReSC {#sec013}

This score depends on two variables: stone number and stone location. Nine locations are identified and one point is given for each location involved, except for the inferior pole which is allocated 2 points.

### Ito's nomogram {#sec014}

This score is calculated from five variables: stone volume (0/5/8/13 point(s)); presence of lower pole calculi (0/5 point(s)); operator with experience of \>50 f-URS (0/3 point(s)); stone number (0/2 point(s)); presence of hydronephrosis (0/2 point(s)). Total nomogram score (0 to 25 points) is derived from adding up the individual scores. In contrast to the other three scores, a high total score is predictive of a successful f-URS outcome.

SFR was defined by the total absence of residual stone after rigorous examination at the end of the procedure. After stone removal, all calyces were inspected on a visual display under radioscopic control. If fragments or dust remained, scans were repeated up to 6 months to search for new aggregates. The patient was systematically considered to be non-stone-free (SF) if imaging was positive for the presence of stones. If postsurgical inspection was totally clear, the absence of clinical complications or CT proof of stone recurrence during the 6-month follow-up confirmed that the patient was SF.

Ethical approval {#sec015}
----------------

This study was approved by the Institutional Ethics Committee of University Hospital of Besancon. All data were anonymized. The Ethics committee waived the requirement for informed consent.

Statistical analysis {#sec016}
--------------------

Analysis was performed using the Chi-square test for categorical variables and Mann Whitney U test for continuous variable. A p value of \<0.05 was considered statistically significant. Area under the curve of receiver operating characteristics curve (AUC-ROC) was used to evaluate the performance of the scores. All statistical analyses were performed using XLSTAT Premium software version 20.1 (Addinsoft^®^, Brooklyn, NY, USA).

Results {#sec017}
=======

Patient characteristics and surgical outcome {#sec018}
--------------------------------------------

A total of 800 procedures carried out between January 2009 and December 2016 were analysed. The characteristics of the patients and procedures are shown in [Table 1](#pone.0237068.t001){ref-type="table"}.

10.1371/journal.pone.0237068.t001

###### Patient demographics, stone characteristics, procedure characteristics and complications.

![](pone.0237068.t001){#pone.0237068.t001g}

                                         Stone group     
  -------------------------------------- --------------- ---------------
  **Patients**                                           
  Number of procedures                   800             669
  Number of patients                     577             484
  Mean age (years)                       52.3 ± 16.8     52.5 ±16.7
  Gender (n, %)                                          
   Female                                300 (37.5%)     264 (39.5%)
   Male                                  500 (62.5%)     405 (61.5%)
  Mean BMI (kg/m²)                       26.6 ± 5.9      26.6± 6.0
  **Stones**                                             
  Size (mm)                              10.9 ± 8.8      11.5 ± 9.0
  Procedures with stone \>20 mm (n, %)   84 (10.5%)      87 (13.0%)
  Average Hounsfield Unit                780.2 ± 334.1   783.0 ± 337.5
  Mean number of stones                  1.9 ± 1.3       2.0 ± 1.4
  **Procedure**                                          
  Previous treatment (n, %)                              
   RIRS                                  146 (18.3%)     138 (20.6%)
   ESWL                                  89 (11.1%)      79 (11.8%)
   PCNL                                  28 (3.5%)       28 (4.2%)
  Pre-stenting (n, %)                                    
   Double J stent                        515 (64.4%)     426 (63.7%)
   Percutaneous nephrostomy              6 (0.8%)        2 (0.3%)
  Duration (min)                         93.1 ± 41.7     97.1 ± 42.5
  Ureteral dilation (n, %)               40 (5.0%)       35 (5.2%)
  Access sheath (n, %)                   698 (87.3%)     606 (90.6%)
  Hospital stay (days)                   3.3 ± 2.0       3.3 ± 1.9
  Post-operative stenting (n, %)                         
   None                                  108 (13.5%)     78 (11.7%)
   Mono J Stent                          124 (15.5%)     104 (15.6%)
   Double J stent                        568 (71.0%)     489 (73.1%)
  SFR                                    593 (74.1%)     482 (72.1%)
  **Complications (n, %)**                               
  All grades                             85 (10.6%)      69 (10.3%)
  Clavien I                              40 (5.0%)       32 (4.8%)
  Clavien II                             41 (5.1%)       33 (4.9%)
  Clavien III                            3 (0.4%)        3 (0.5%)
  Clavien IV                             0               0
  Clavien V                              1 (0.1%)        1 (0.2%)

BMI: body mass index; RIRS: retrograde intra renal surgery; ESWL: extracorporeal shockwave lithotripsy; PCNL: percutaneous nephrolithotomy; SFR: stone-free rate.

Overall, there were 500 males (62.5%) and 300 females (37.5%), mean (SD) age was 52.3 ± 16.8 years and mean BMI was 26.6 ± 5.9 kg/m^2^. Mean diameter of the stones was 10.9 ± 8.8 mm, mean renal stone density was 780.2 ± 334.1 HU and mean number of stones per patient was 1.9 ± 1.3. Repartition of chemical composition: 66% were calcium oxalate, 14% were calcium phosphate, 9% were uric acid and 11% were other. There were 515 (64.4%) double J stents. Ureteral dilation was required in 40 cases (5%), an access sheath was used in 698 procedures (87.3%) and mean operation time was 93.1 ± 41.7 min. SFR was 74.1% (n = 593). The complication rate was 10.6% (n = 85) and most complications were mild: Clavien-Dindo grade III complications were observed in three patients only (0.4%). After exclusion of ureteral procedures (131 patients), the RO group had similar characteristics, with a SFR of 72.1%.

Analysis of patient and stone characteristics {#sec019}
---------------------------------------------

The characteristics of the patients and stones were compared between the SF and non-SF groups ([Table 2](#pone.0237068.t002){ref-type="table"}).

10.1371/journal.pone.0237068.t002

###### Univariate analysis of patient and stone characteristics.

![](pone.0237068.t002){#pone.0237068.t002g}

                                                                      Stone-free         p value            
  ------------------------------------------------------- ----------- ------------------ ------------------ ----------
  UR procedure (n, %)                                     UR          593 (74.1%)        207 (25.9%)        
  RO procedure (n, %)                                     RO          482 (72.1%)        187 (27.9%)        
  Age (years)                                             UR          52.0 ± 16.7        53.2 ± 17.1        0.405
  BMI (kg/m^2^)                                           UR          26.4 ± 5.7         27.1 ± 6.2         0.125
  Size (mm)                                               UR          9.2 ± 5.8          16.6 ± 11.8        \<0.0001
  Volume (mm^3^)                                          UR          1348.8 ± 10634.0   7924.0 ± 27335.0   \<0.0001
  No. of stones                                           UR          1.8 ± 1.3          2.1 ± 1.4          0.004
  RO                                                      2.0 ± 1.4   2.2 ± 1.4          0.046              
  Stone density (HU)                                      UR          788.6 ± 342.3      756.2 ± 308.9      0.323
  Pre-stenting (yes/total and % yes)                      UR          385/593            130/207            0.564
  (65.0%)                                                 (62.8%)                                           
  Lower pole location (yes/total and % yes)               RO          308/482            128/187            0.268
  (63.9%)                                                 (68.4%)                                           
  IPA in degrees                                          RO          51.5 ± 9.1         48.6 ± 9.1         0.003
  Lower pole location + IPA \<45° (yes/total and % yes)   RO          71/482             43/187             0.011
  (14.7%)                                                 (23.0%)                                           

HU: Hounsfield Unit; UR: ureteral and renal; RO: renal only; IPA: infundibulopelvic angle.

Univariate analysis showed that stone size (9.2 ± 5.8 vs. 16.6 ± 11.8 mm, p\<0.0001), stone volume (1348.8 ± 10634.0 vs. 7924.0 ± 27335.0 mm^3^, p\<0.0001), stone number (1.8 ± 1.3 vs. 2.1 ± 1.4. p = 0.004), lower pole IPA (51.5 ± 9.1° vs. 48.6 ± 9.1°, p = 0.003) and lower pole location + IPA \<45° (14.7% vs. 23.0%, p = 0.011) were significantly different between the two groups. No statistical difference was found for stone density (788.6 ± 342.3 vs. 756.2 ± 308.9 HU, p = 0,323), pre-stenting (65.0% vs. 62.8%, p = 0.564) and lower pole location (63.9% vs. 68.4%, p = 0.268).

Score analysis {#sec020}
--------------

By univariate analysis all scores differed between the SF and non-SF groups ([Table 3](#pone.0237068.t003){ref-type="table"}): 9.223 ± 1.778 vs. 10.005 ± 1.685 (p\<0.0001) for the S.T.O.N.E score; 0.064 ± 0.319 vs. 0.471 ± 0.778 (p\<0.0001) for the RUSS score; 2.643 ± 1.580 vs. 3.455 ± 1.717 (p\<0.0001) for the Modified ReSC score; and 14.05 ± 5.24 vs. 9.17 ± 5.82 (p\<0.0001) for Ito's nomogram.

10.1371/journal.pone.0237068.t003

###### Univariate analysis of scores and nomogram.

![](pone.0237068.t003){#pone.0237068.t003g}

                                                 Stone-free      p value          
  ---------------------------------------------- --------------- ---------------- ----------
  **S.T.O.N.E score (UR: 800 procedures)**       9.223 ± 1.778   10.005 ± 1.685   \<0.0001
  S (size) (1--3 pts)                            2.150 ± 0.598   2.623 ± 0.560    \<0.0001
  T (topography) (1--3 pts)                      2.364 ± 0.766   2.551 ± 0.636    0.002
  O (obstruction) (1--3 pts)                     1.374 ± 0.484   1.406 ± 0.492    0.424
  N (number of stones) (1--3 pts)                1.644 ± 0.805   1.831 ± 0.835    0.005
  E (evaluation of HU) (1--3 pts)                1.696 ± 0.805   1.623 ± 0.784    0.252
  **RUSS score (RO: 669 procedures)**            0.064 ± 0.319   0.471 ± 0.778    \<0.0001
  Stone size \>20 mm (1pt per 10 mm)             20/482          59/187           \<0.0001
  (yes/total and % yes)                          (4.1%)          (31.6%)          
  Lower pole location + IPA \<45° (1 pt)         71/482          43/187           0.011
  (yes/total and % yes)                          (14.7%)         (23.0%)          
  Stone number in different calyces \>1 (1 pt)   110/482         70/187           0.0001
  (yes/total and % yes)                          (22.8%)         (37.4%)          
  Abnormal renal anatomy (1 pt)                  2/482           2/187            0.324
  (yes/total and % yes)                          (0.4%)          (1.1%)           
  **Seoul modified (RO: 669 procedures)**        2.643 ± 1.580   3.455 ± 1.717    \<0.0001
  **Ito's score (RO: 669 procedures)**           14.05 ± 5.24    9.17 ± 5.82      \<0.0001
  Stone volume (n, %)                                                             \<0.0001
   ≤ 500 (13 pts)                                303 (62.9%)     45 (24.1%)       
   500 \<v≤ 1000 (8 pts)                         85 (17.6%)      39 (20.9%)       
   1000 \<v≤ 2000 (5 pts)                        50 (10.4%)      29 (15.5%)       
    \>2000 (0 pts)                               44 (9.1%)       74 (39.6%)       
  No lower pole calculi (yes/total)              174/482         59/187           0.268
  (%yes) (5 pts)                                 (36.1%)         (31.6%)          
  Operator experience ≥ 50 (yes/total)           244/482         97/187           0.772
  (%yes) (3 pts)                                 (50.6%)         (51.8%)          
  Absence of hydronephrosis (yes/total)          294/482         113/187          0.893
  (% absent) (2 pts)                             (61.0%)         (60.4%)          
  Number of stones (solitary/total)              223/482         73/187           0.09
  (% solitary) (2 pts)                           (46.3%)         (39.0%)          

UR: ureteral and renal; RO: renal only; RUSS: Resolu-Unsal Stone Score; HU: Hounsfield Unit; IPA: infundibulopelvic angle.

AUC ROC was calculated for the four scores ([Fig 1](#pone.0237068.g001){ref-type="fig"}).

![ROC curves for Ito's nomogram, S.T.O.N.E score, RUSS score and modified S- ReSC score.\
S.T.O.N.E score AUC ROC was 0.617 \[95%CI: 0.575--0.660\], RUSS AUC ROC was 0.644 \[95%CI: 0.609--0.680\], modified S-ReSC AUC ROC was 0.651 \[96%CI: 0.606--0.697\] and Ito's nomogram AUC ROC was 0.735 \[95%CI: 0.692--0.777\].](pone.0237068.g001){#pone.0237068.g001}

Discussion {#sec021}
==========

The indications for f-URS have increased considerably over the past few years due to improvements in materials and techniques. f-URS is now the preferred technique before ESWL and PCNL and is associated with few complications, which are mainly low grade \[[@pone.0237068.ref018]\]. However, prediction of the results of f-URS using scores is essential for patient management.

In our patient cohort, scores were significantly different between the SF and non-SF groups. The AUC ROC for the four scores were predictive of SFR at an intermediate level of prediction \[[@pone.0237068.ref019]\]. The AUC ROC for the scores were lower than in developmental studies: Jung et al. 0.766 for the ReSC score \[[@pone.0237068.ref013]\], Molina et al. 0.764 for the S.T.O.N.E score \[[@pone.0237068.ref014]\], Resorlu et al. \[[@pone.0237068.ref012]\] did not calculate the AUC ROC for the RUSS score, and Ito et al. reported a higher AUC ROC: 0.87 \[[@pone.0237068.ref015]\]. However, our lower AUC ROC concurs with two other validations: Erbin et al. reported an AUC ROC of 0.655 for the RUSS and 0.593 for the modified ReSC \[[@pone.0237068.ref020]\]. Park et al. reported an AUC ROC of 0.701 for the modified ResC \[[@pone.0237068.ref021]\]. Furthermore, external validation of the PCNL score also gave an inferior AUC ROC to developmental studies \[[@pone.0237068.ref022], [@pone.0237068.ref023]\].

Although the differences between the f-URS scores were not significant, the nomogram of Ito et al. \[[@pone.0237068.ref015]\] appears to be the most predictive, in accordance with previous studies. If we consider each variable individually, obstruction was not considered a significant factor in our study. This supports the results of Molina et al. who failed to demonstrate the significance of obstruction (0.5 \[95%CI: -1.1--0.1\], p = 0.077) \[[@pone.0237068.ref014]\]. The impact of obstruction is difficult to evaluate as the rate of pre-stenting was high among our patients. Furthermore, Rubenstein et al. demonstrated a difference in the presence of pre-stenting in contrast to a previous study in our centre \[[@pone.0237068.ref024], [@pone.0237068.ref025]\]. No significant difference has been reported for density, as reported by Molina et al. \[[@pone.0237068.ref014]\]. These two variables (obstruction and density) have a tendency to lower the predictive value of the S.T.O.N.E score. Lower pole location and IPA angle is a unique paring. Our study confirms the findings of Resorlu et al., although calculating the IPA angle appears to give slightly superior results. IPA was demonstrated to be significant by Inoue et al. and Jessen et al., even using a cut-off of 30° \[[@pone.0237068.ref026], [@pone.0237068.ref027]\]. Measurements were made as described by Elbahnasy et al., but Sampaio et al. suggested another method using stone position \[[@pone.0237068.ref028], [@pone.0237068.ref029]\]. It is also the only score that considers musculoskeletal deformities and renal malformations. To date, no study has assessed the effect of renal malformation on SFR after f-URS. Resorlu et al. found a SFR of 66.7% (10/15) vs. 87.5% (168/192) (p = 0.04), respectively in patients with or without renal malformations. Although renal malformation should intuitively lower the SFR, the effect seems to be moderate and needs to be confirmed. Our study did not identify enough cases of renal malformation to draw any conclusions. The four criteria of the score are also very restrictive, giving excellent specificity but poor sensitivity. The modified ReSC score focusses on two variables: stone number and location. It is the easiest and most practical score to use. However, visualisation of the calyceal is not always easy. The score described by Ito et al. \[[@pone.0237068.ref015]\] appears to be the most predictive. However, the use of a paper nomogram is required. Weighting of these variables, particularly 'stone volume', seems to enhance its results ('stone volume' graded from 0 to 13 points, on a total score ranging from 0 to 25 points). In contrast to the report of Ito et al., stone volume in our study was estimated using only maximal diameter. The performance of this variable did not seem to be affected by this quicker method. The other variables did not appear to be significant in our study. As in a previous study in our centre, stone location, in particular lower pole location, did not have any impact on the efficacy and morbidity of f-URS \[[@pone.0237068.ref030]\].

Our study has several advantages and limitations. In addition to our cohort being the largest described to date, the study also involved a number of surgeons (12 operators) with different levels of experience (residents, novices and experienced surgeons) reflecting real-life urological practice. Furthermore, only one person was involved in calculating the four scores. The limitations of our study include its retrospective nature, a source of important bias. A SFR of 74% is similar to the external validation studies of Erbin et al. and Parks et al. (respectively 70.1% and 73%). For statistical and practical reasons, the definition of SFR is a single stone for all scores. This is precise and is defined by a total absence of stone and not by an absence of stone sized \>4 or \>2 mm. This definition can contribute to decrease the AUC ROC. One of the limitations of our study is the absence of systematic post-operative imaging. However, endoscopic and fluoroscopic end of procedure inspection was always performed. This technique has shown good sensitivity and specificity at detecting residual stone fragments \[[@pone.0237068.ref031]\]. The simultaneous evaluation of these four scores on a single cohort requires non-restrictive inclusion criteria, whereas some score variables were exclusion criteria in other studies. Our choice better reflects daily practice.

A large, multicentre, prospective study, recording all variables, would allow the validity of these scores to be defined. An ideal score should be sensitive and available for all patients, but it will be difficult to combine performance and simplicity/efficiency. Based on our results it is difficult to rank the different scores according their accuracy. We found that four main factors: stone size, stone number, lower pole and IPA \<45° affected the scores. Moreover, we should also ask what the clinical impact of these scores is. Independent of the information given to patients and possibly to help in the choice of surgical technique, these kind of scores are not clinically useful and are not used routinely due to their difficulty and the time required to calculate them. The RUSS score needs IPA angle definition on a computed tomography scan and the Ito score requires the use of a nomogram and measurement of the stone volume. Conversely, the S.T.O.N.E. score can be calculated mentally in daily practice and the Seoul score would be easiest to use.

Future studies should also analyse inter- and intra-observer variability. Automatic analysis of pre-operative images by artificial intelligence programs could occur in the near future.

Conclusion {#sec022}
==========

A number of scores have been established to predict SFR after RIRS. The four scores evaluated in this study were all predictive of SFR after f-URS. The score of Ito et al. appeared to be the most sensitive. We also tested the ability of the score to predict complications. None of the four scores were predictive of the complication rate in RIRS. Other nomograms could be developed in this area.

Supporting information {#sec023}
======================

###### 

(XLSX)

###### 

Click here for additional data file.

10.1371/journal.pone.0237068.r001

Decision Letter 0

Riveiro Rodríguez

Antonio

Academic Editor

© 2020 Antonio Riveiro Rodríguez

2020

Antonio Riveiro Rodríguez

This is an open access article distributed under the terms of the

Creative Commons Attribution License

, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

15 Apr 2020

PONE-D-20-00720

Evaluation and comparison of different nomograms for predicting stone-free status after flexible ureteroscopy for renal and ureteral stones

PLOS ONE

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Reviewers\' comments:

Reviewer\'s Responses to Questions

**Comments to the Author**

1\. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer \#1: Yes

Reviewer \#2: Partly

\*\*\*\*\*\*\*\*\*\*

2\. Has the statistical analysis been performed appropriately and rigorously?

Reviewer \#1: Yes

Reviewer \#2: Yes

\*\*\*\*\*\*\*\*\*\*

3\. Have the authors made all data underlying the findings in their manuscript fully available?

The [PLOS Data policy](http://www.plosone.org/static/policies.action#sharing) requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data---e.g. participant privacy or use of data from a third party---those must be specified.

Reviewer \#1: Yes

Reviewer \#2: Yes

\*\*\*\*\*\*\*\*\*\*

4\. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer \#1: No

Reviewer \#2: Yes

\*\*\*\*\*\*\*\*\*\*

5\. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer \#1: The study aims to compare four previously developed predictive scores for stone-free rate (SFR) after flexible ureterorenoscopy (f-URS) with holmium-YAG laser fragmentation of renal and ureteral lithiasis. The study was single-center and used between 669-800 procedures to evaluate the four predictive scores. Two scores have been previously validated- the Resolu Unsal Stone Score (RUSS) and modified Seoul National University Renal Stone Complexity (S-ReSC) score. The other two scores, the S.T.O.N.E score described by Molina et al. and Ito's nomogram have not been validated in any other cohorts.

The study has a clear objective, the end point is concretely defined, and the analysis is straightforward. However, the generalizability of the findings is unclear especially since this is a single center study with fewer than 1000 cases and the use of a single rater. Overall, this manuscript sets the stage for future studies that can further validate the clinical utility of the predictive scores.

Major points:

1\) Inclusion of the absolute numbers of patients would be informative for Tables 1 and 2. For example, how many patients are in UR and RO groups for Table 1? How many patients are in the Yes and No groups for Table 2?

2\) It is very difficult for this reader to decipher information in Table 2. It is difficult to calculate the percentages by how the authors display the numbers. The authors describe the proportion of patients by no/yes and %yes. I believe it is easier to interpret the percentages if the authors present the fraction of patients who were yes/total patients. For example, the pre-stenting group is show as \"207/385\". It should be changed to 385/592 or 65% so that the reader can see more easily for how the percentages were calculated. This should be done for all of the fractions in Tables 2 and 3.

3\) Table 3: STONE score section is very difficult to interpret. What do the numbers represent? I believe that it is unrealistic to expect the reader to be familiar with the STONE score section without an explanation for what the scores mean. Some context in the manuscript would be helpful so that the reader can understand the basics of the STONE score system.

4\) Table 3 has error in reporting the data

Lower pole location- %yes = 85.7%, not 14.3% (yes group)

Lower pole location- %yes = 75.9%, not 24.1% (no group)

Stone number in different calyces \> 1 - %yes = 22.8%, not 37.4% (yes group)

Stone number in different calyces \> 1 - %yes = 37.4%, not 22.8% (no group)

Hydronephrosis- %absent = 61%, not 39% (yes group)

Hydronephrosis- %absent = 60.4%, not 39.6% (no group)

5\) For a non-urology audience it is unclear what role a predictive score for SFR would play in clinical decision making. It would be helpful to address the following in the discussion: if there was a perfect predictive score that was 100% sensitive and specific, would a particular score keep a physician from intervening with f-URS or rather is the score meant to be helpful for patient counseling and managing patient expectations. Explicitly stating the clinical impact of using a predictive score would be useful context.

Reviewer \#2: The authors evaluated four predictive scoring models for stone-free rate after flexible ureteroscopic urinary stone surgery. Major pitfall of the study is lack of systemic and consistent post-operative imaging to evaluate stone-free. I have some other concerns and questions.

1\. Title: I think all of them are not nomograms, but they are predictive model or scoring system. Thus, the title should be revised with appropriate term.

2\. Stone composition analysis is importance information when interpreting results of urinary stone surgery. Please, provide the results (at lease, proportion of uric acid stone)

3\. How many surgeons involved the study? Didn\'t they have different patient selection or surgical outcomes? How did you adjust for surgeon effect?

Please, additionally provide brief description of their experience.

4\. The major advantage of the study is concurrent comparison of 4 existing predictive models to predict stone-free after flexible ureteroscopic stone surgery. If you discuss it in practical aspect with balanced manner, not only focusing to the predictive ability, it can be very valuable discussion. For example, granularity of score or how many factors do they need can effect the predictive ability. By contrast, how difficult to calculate the score and how much time do they need can diminish the ability and clinical usefulness.

\*\*\*\*\*\*\*\*\*\*

6\. PLOS authors have the option to publish the peer review history of their article ([what does this mean?](https://journals.plos.org/plosone/s/editorial-and-peer-review-process#loc-peer-review-history)). If published, this will include your full peer review and any attached files.

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**Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our [Privacy Policy](https://www.plos.org/privacy-policy).

Reviewer \#1: No

Reviewer \#2: Yes: Chang Wook Jeong

\[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link \"View Attachments\". If this link does not appear, there are no attachment files to be viewed.\]

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10.1371/journal.pone.0237068.r002

Author response to Decision Letter 0

2 Jun 2020

Dear Dr. Joerg HEBER,

We thank the Editorial Board and the reviewers for their critical and empathic assessment of our work. Their comments allowed us to improve the quality of our work. In the following letter we address a point by point answer to their comments.

We hope that the Editorial Board as well as the expert reviewers will find our manuscript of interest for the readership of Plos One.

With my best regards,

Pr. François Kleinclauss, (MD, PhD)

Point by point answer : All responses to corrector are specified in the file : \"Responses to reviewers\"

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The file naming have been changed

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We Provide additional information in the online submission.

All data were anonymized

Ethics committee waived the requirement for informed consent.

The « Délégation a la Recherche Clinique et à l'innovation » approved the study. This institution is certified ISO9001v15.

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The authors received no specific funding for this work. The authors didn't receive a salary.

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The cover letter has been modified.

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This information should be included in your cover letter; we will change the online submission form on your behalf.

The cover letter has been modified.

"We have no conflicts of interest to disclose." change to "The authors have declared that no competing interests exist." in the cover letter.

Please know it is PLOS ONE policy for corresponding authors to declare, on behalf of all authors, all potential competing interests for the purposes of transparency. PLOS defines a competing interest as anything that interferes with, or could reasonably be perceived as interfering with, the full and objective presentation, peer review, editorial decision-making, or publication of research or non-research articles submitted to one of the journals. Competing interests can be financial or non-financial, professional, or personal. Competing interests can arise in relationship to an organization or another person. Please follow this link to our website for more details on competing interests:<http://journals.plos.org/plosone/s/competing-interests>

Reviewers\' comments:

Reviewer\'s Responses to Questions

Reviewer \#1: The study aims to compare four previously developed predictive scores for stone-free rate (SFR) after flexible ureterorenoscopy (f-URS) with holmium-YAG laser fragmentation of renal and ureteral lithiasis. The study was single-center and used between 669-800 procedures to evaluate the four predictive scores. Two scores have been previously validated- the Resolu Unsal Stone Score (RUSS) and modified Seoul National University Renal Stone Complexity (S-ReSC) score. The other two scores, the S.T.O.N.E score described by Molina et al. and Ito's nomogram have not been validated in any other cohorts.

The study has a clear objective, the end point is concretely defined, and the analysis is straightforward. However, the generalizability of the findings is unclear especially since this is a single center study with fewer than 1000 cases and the use of a single rater. Overall, this manuscript sets the stage for future studies that can further validate the clinical utility of the predictive scores.

Major points:

1\) Inclusion of the absolute numbers of patients would be informative for Tables 1 and 2. For example, how many patients are in UR and RO groups for Table 1? How many patients are in the Yes and No groups for Table 2?

We added the number of patients and the number of procedures in Table 1 : "Number of patients : 577 for UR group and 484 patients for RO group"

Nevertheless, each procedure was considered on an individual basis.

In Table 2, we added the number of procedures in each group.

2\) It is very difficult for this reader to decipher information in Table 2. It is difficult to calculate the percentages by how the authors display the numbers. The authors describe the proportion of patients by no/yes and %yes. I believe it is easier to interpret the percentages if the authors present the fraction of patients who were yes/total patients. For example, the pre-stenting group is show as \"207/385\". It should be changed to 385/592 or 65% so that the reader can see more easily for how the percentages were calculated. This should be done for all of the fractions in Tables 2 and 3.

The suggested modifications have been made for Tables 2 and 3.

3\) Table 3: STONE score section is very difficult to interpret. What do the numbers represent? I believe that it is unrealistic to expect the reader to be familiar with the STONE score section without an explanation for what the scores mean. Some context in the manuscript would be helpful so that the reader can understand the basics of the STONE score system.

The STONE score and the other scores are defined in the Material and Method section. The scoring system has been added in the table 3. We add line 103 "(5 to 15 points). A high total score is predictive of a failure f-URS outcome."

4\) Table 3 has error in reporting the data

Lower pole location- %yes = 85.7%, not 14.3% (yes group)

Lower pole location- %yes = 75.9%, not 24.1% (no group)

We checked all the data. After verification there was a little error in these data. However, these numbers correspond to Lower pole location associated with infendibulo-pelvic angle \< 45°.

71/482 (14,7%) of the procedures includes these parameters for 'Yes stone free groupe'

43/187 (23.0%) of the procedures includes these parameters for 'No stone free groupe'

Stone number in different calyces \> 1 - %yes = 22.8%, not 37.4% (yes group)

The suggested modifications have been made.

Stone number in different calyces \> 1 - %yes = 37.4%, not 22.8% (no group)

The suggested modifications have been made.

Hydronephrosis- %absent = 61%, not 39% (yes group)

Hydronephrosis- %absent = 60.4%, not 39.6% (no group)

The suggested modifications have been made. We reported the percentage of absent hydronephrosis because in this score, the absence of hydronephrosis is quoted.

Similarly, "lower pole calculi" change to "No lower pole calculi" in Ito's score item, for easier interpretation.

5\) For a non-urology audience it is unclear what role a predictive score for SFR would play in clinical decision making. It would be helpful to address the following in the discussion: if there was a perfect predictive score that was 100% sensitive and specific, would a particular score keep a physician from intervening with f-URS or rather is the score meant to be helpful for patient counseling and managing patient expectations. Explicitly stating the clinical impact of using a predictive score would be useful context.

We completely agree with this comment and add the following sentences in the discussion section line 254 :

"Based on our results it's difficult to rank this different scores, according there accuracy. We found that three factors i.e. stone size, stone number, lower pole and IPA \< 45° mainly impact the scores results. Moreover, the remaining question is the clinical impact of such scores. Independently of the information gave to patients and maybe to help the choice of surgical technique this kind of scores are not clinically very usefull and are not routinely used for many reasons (difficulty and time to calculate). The RUSS score needs IPA angle definition on CT scan, the Ito's score required the use of nomogram and the measurement of the stone volume, the STONE score can be calculated mentally in daily practice and the Seoul score would be the more easy to use."

Answer to Reviewer \#2 :

The authors evaluated four predictive scoring models for stone-free rate after flexible ureteroscopic urinary stone surgery. Major pitfall of the study is lack of systemic and consistent post-operative imaging to evaluate stone-free. I have some other concerns and questions.

We agree with this comment and the absence of systematic post-operative imaging is one of the major bias of our study. This bias is reported in the discussion section. About a half of the patients underwent post-operative imaging but all underwent endoscopic and fluoroscopic inspection after surgery.

1\. Title: I think all of them are not nomograms, but they are predictive model or scoring system. Thus, the title should be revised with appropriate term.

We completely agree with this comment.

The title was changed for " Evaluation and comparison of scoring systems for predicting stone-free status after flexible ureteroscopy for renal and ureteral stones"

2\. Stone composition analysis is importance information when interpreting results of urinary stone surgery. Please, provide the results (at lease, proportion of uric acid stone)

We add these data in the result section and reported the repartition of the stone composition. Line 146 :

"Repartition of chemical composition : 66 % were calcium oxalate, 14% were calcium phosphate, 9% were uriq acid and 11% were other."

3\. How many surgeons involved the study? Didn\'t they have different patient selection or surgical outcomes? How did you adjust for surgeon effect?

Please, additionally provide brief description of their experience.

We add the number of surgeons line 237 : (12 operators)

These procedures were performed by residents, novices and experienced surgeons. This reflects real-life urological practice. The impact of experience and learning curve were not the goal in this paper but are the topics of another paper currently in writing. Moreover, we previouly reported that surgeon with less than 20 f-URS had similar results than surgeon with more than 20 f-URS procedures (Kleinclauss F, EAU2013)

4\. The major advantage of the study is concurrent comparison of 4 existing predictive models to predict stone-free after flexible ureteroscopic stone surgery. If you discuss it in practical aspect with balanced manner, not only focusing to the predictive ability, it can be very valuable discussion. For example, granularity of score or how many factors do they need can effect the predictive ability. By contrast, how difficult to calculate the score and how much time do they need can diminish the ability and clinical usefulness.

We agree with this comment and add a paragraph in the Discussion section about the routine use of such score (line 254) :

"Based on our results it's difficult to rank this different scores, according there accuracy. We found that three factors i.e. stone size, stone number, lower pole and IPA \< 45° mainly impact the scores results. Moreover, the remaining question is the clinical impact of such scores. Independently of the information gave to patients and maybe to help the choice of surgical technique this kind of scores are not clinically very usefull and are not routinely used for many reasons (difficulty and time to calculate). The RUSS score needs IPA angle definition on CT scan, the Ito's score required the use of nomogram and the measurement of the stone volume, the STONE score can be calculated mentally in daily practice and the Seoul score would be the more easy to use."

###### 

Submitted filename: Responses to reviewers.docx

###### 

Click here for additional data file.

10.1371/journal.pone.0237068.r003

Decision Letter 1

Riveiro Rodríguez

Antonio

Academic Editor

© 2020 Antonio Riveiro Rodríguez

2020

Antonio Riveiro Rodríguez

This is an open access article distributed under the terms of the

Creative Commons Attribution License

, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

26 Jun 2020

PONE-D-20-00720R1

Evaluation and comparison of scoring systems for predicting stone-free status after flexible ureteroscopy for renal and ureteral stones

PLOS ONE

Dear Dr. Kleinclauss,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE's publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

From a scientific point of view, this work is acceptable, however, it is suggested the improvement of the quality of the text as pointed out by Reviewer 1.

Please submit your revised manuscript by Aug 10 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at <plosone@plos.org>. When you\'re ready to submit your revision, log on to <https://www.editorialmanager.com/pone/> and select the \'Submissions Needing Revision\' folder to locate your manuscript file.

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If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: <http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols>

We look forward to receiving your revised manuscript.

Kind regards,

Antonio Riveiro Rodríguez, PhD

Academic Editor

PLOS ONE

\[Note: HTML markup is below. Please do not edit.\]

Reviewers\' comments:

Reviewer\'s Responses to Questions

**Comments to the Author**

1\. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the "Comments to the Author" section, enter your conflict of interest statement in the "Confidential to Editor" section, and submit your \"Accept\" recommendation.

Reviewer \#1: All comments have been addressed

Reviewer \#2: All comments have been addressed

\*\*\*\*\*\*\*\*\*\*

2\. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer \#1: Yes

Reviewer \#2: Yes

\*\*\*\*\*\*\*\*\*\*

3\. Has the statistical analysis been performed appropriately and rigorously?

Reviewer \#1: Yes

Reviewer \#2: Yes

\*\*\*\*\*\*\*\*\*\*

4\. Have the authors made all data underlying the findings in their manuscript fully available?

The [PLOS Data policy](http://www.plosone.org/static/policies.action#sharing) requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data---e.g. participant privacy or use of data from a third party---those must be specified.

Reviewer \#1: No

Reviewer \#2: Yes

\*\*\*\*\*\*\*\*\*\*

5\. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer \#1: Yes

Reviewer \#2: Yes

\*\*\*\*\*\*\*\*\*\*

6\. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer \#1: The following comments were adequately addressed:

1\. The authors have added UR and RO patient numbers to Tables 1 and 2 and now provide helpful context.

2\. The authors have provided fractions in Table 2 and now the data presentation is more clear.

3\. The authors have provided a range for the S.C.OR.E system and they now provide an explanation for the meaning of a high score in line 103.

Minor Revisions:

1\. We request that the authors take the time to make sure that the writing is clear and that grammar is used correctly. For example, there is a passage in the Discussion section that reads (starting line 259):

\"Independently of the information gave to patients and maybe to help the choice of surgical technique this kind of scores are not clinically very usefull and are not routinely used for many reasons (difficulty and time to calculate).\"

It is not clear to me what the authors are trying to say here. Please also spell check the document.

Starting line 261: \"The RUSS score needs IPA angle definition on CT scan, the Ito's score required the use of nomogram and the measurement of the stone volume, the STONE score can be calculated mentally in daily practice and the Seoul score would be the more easy to use.\"

There are 5 sentences here that are connected together into 1 large sentence. Please make this sentence more clear to the reader, perhaps the authors should break up the sentence into smaller sentences.

2\. Please make uniform use of the decimal point or the comma. Please be consistent with the usage according to PLOS-ONE guidelines. For example:

Table 2, Lines 1 and 2 should read \"25.9\" and \"27.9\" as opposed to \"25,9\" and \"27,9.\"

Table 3, missing a paranthesis before \"14.7)\" and should read \"36.1\" as opposed to \"36,1\".

3\. In the Discussion section, there are three 1-sentence paragraphs and two 2-3 sentence paragraphs. In general, paragraphs should contain a collection of sentences that convey a related thought or message. The Discussion section could benefit from fewer paragraphs that are longer, rather than several 1-2 sentence paragraphs.

Reviewer \#2: Thanks for the appropriate revision.

One minor thing should be corrected before publication; \"uriq acid\" \--\> \"uric acid\".

\*\*\*\*\*\*\*\*\*\*

7\. PLOS authors have the option to publish the peer review history of their article ([what does this mean?](https://journals.plos.org/plosone/s/editorial-and-peer-review-process#loc-peer-review-history)). If published, this will include your full peer review and any attached files.

If you choose "no", your identity will remain anonymous but your review may still be made public.

**Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our [Privacy Policy](https://www.plos.org/privacy-policy).

Reviewer \#1: No

Reviewer \#2: No

\[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link \"View Attachments\". If this link does not appear, there are no attachment files.\]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, <https://pacev2.apexcovantage.com/>. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at <figures@plos.org>. Please note that Supporting Information files do not need this step.

10.1371/journal.pone.0237068.r004

Author response to Decision Letter 1

29 Jun 2020

Point by point answer :

Reviewers\' comments:

6\. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer \#1: The following comments were adequately addressed:

1\. The authors have added UR and RO patient numbers to Tables 1 and 2 and now provide helpful context.

2\. The authors have provided fractions in Table 2 and now the data presentation is more clear.

3\. The authors have provided a range for the S.C.OR.E system and they now provide an explanation for the meaning of a high score in line 103.

Minor Revisions:

1\. We request that the authors take the time to make sure that the writing is clear and that grammar is used correctly. For example, there is a passage in the Discussion section that reads (starting line 259):

\"Independently of the information gave to patients and maybe to help the choice of surgical technique this kind of scores are not clinically very usefull and are not routinely used for many reasons (difficulty and time to calculate).\"

It is not clear to me what the authors are trying to say here. Please also spell check the document.

The suggested modifications have been made. We change this passage to " Based on our results it is difficult to rank the different scores according their accuracy. We found that four main factors: stone size, stone number, lower pole and IPA \<45° affected the scores. Moreover, we should also ask what the clinical impact of these scores is. Independent of the information given to patients and possibly to help in the choice of surgical technique, these kind of scores are not clinically useful and are not used routinely due to their difficulty and the time required to calculate them."

We also spell check the document.

Starting line 261: \"The RUSS score needs IPA angle definition on CT scan, the Ito's score required the use of nomogram and the measurement of the stone volume, the STONE score can be calculated mentally in daily practice and the Seoul score would be the more easy to use.\"

There are 5 sentences here that are connected together into 1 large sentence. Please make this sentence more clear to the reader, perhaps the authors should break up the sentence into smaller sentences.

The suggested modifications have been made. We change this sentence to : "The RUSS score needs IPA angle definition on a computed tomography scan and the Ito score requires the use of a nomogram and measurement of the stone volume. Conversely, the S.T.O.N.E. score can be calculated mentally in daily practice and the Seoul score would be easiest to use."

2\. Please make uniform use of the decimal point or the comma. Please be consistent with the usage according to PLOS-ONE guidelines. For example:

Table 2, Lines 1 and 2 should read \"25.9\" and \"27.9\" as opposed to \"25,9\" and \"27,9.\"

The suggested modifications have been made.

Table 3, missing a paranthesis before \"14.7)\" and should read \"36.1\" as opposed to \"36,1\".

The suggested modifications have been made.

3\. In the Discussion section, there are three 1-sentence paragraphs and two 2-3 sentence paragraphs. In general, paragraphs should contain a collection of sentences that convey a related thought or message. The Discussion section could benefit from fewer paragraphs that are longer, rather than several 1-2 sentence paragraphs.

The suggested modifications have been made.

Some paragraphs have been grouped.

Reviewer \#2: Thanks for the appropriate revision.

One minor thing should be corrected before publication; \"uriq acid\" \--\> \"uric acid\".

This modification have been made.

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10.1371/journal.pone.0237068.r005

Decision Letter 2

Riveiro Rodríguez

Antonio

Academic Editor

© 2020 Antonio Riveiro Rodríguez

2020

Antonio Riveiro Rodríguez

This is an open access article distributed under the terms of the

Creative Commons Attribution License

, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

21 Jul 2020

Evaluation and comparison of scoring systems for predicting stone-free status after flexible ureteroscopy for renal and ureteral stones

PONE-D-20-00720R2

Dear Dr. Kleinclauss,

We're pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you'll receive an e-mail detailing the required amendments. When these have been addressed, you'll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Antonio Riveiro Rodríguez, PhD

Academic Editor

PLOS ONE

Reviewers\' comments:

Reviewer\'s Responses to Questions

**Comments to the Author**

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Reviewer \#1: All comments have been addressed

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Reviewer \#1: Yes

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Reviewer \#1: Yes

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Reviewer \#1: Yes

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Reviewer \#1: Yes

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Reviewer \#1: All comments addressed from the previous review.

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Reviewer \#1: No

10.1371/journal.pone.0237068.r006

Acceptance letter

Riveiro Rodríguez

Antonio

Academic Editor

© 2020 Antonio Riveiro Rodríguez

2020

Antonio Riveiro Rodríguez

This is an open access article distributed under the terms of the

Creative Commons Attribution License

, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

28 Jul 2020

PONE-D-20-00720R2

Evaluation and comparison of scoring systems for predicting stone-free status after flexible ureteroscopy for renal and ureteral stones

Dear Dr. Kleinclauss:

I\'m pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they\'ll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact <onepress@plos.org>.

If we can help with anything else, please email us at <plosone@plos.org>.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Antonio Riveiro Rodríguez

Academic Editor

PLOS ONE

[^1]: **Competing Interests:**The authors have declared that no competing interests exist.
