Prospective evaluation of complications using the modified Clavien grading system, and of success rates of percutaneous nephrolithotomy using Guy's Stone Score: A single-center experience

Does success in percutaneous nephrolithotomy depend only on stone size? Analysis of the predictive capacity for success and complications of the current nephrolithometry scoring systems and their relationship with the stone surface

OBJECTIVE

To analyze the predictive capacity of the nephrolithometry scoring systems (GSS, STONE, CROES and S-ReSC) and stone surface regarding success and complications following percutaneous nephrolithotomy (PCNL).

METHODS

We studied 392 patients who had undergone PCNL in our center. Only patients with a non-contrast CT (n = 240) were finally included for analysis. The predictive capacities for success and complications of the different scoring systems were evaluated using ROC curves and their area under the curve (AUC).

RESULTS

Regarding success, the S-ReSC system had the highest predictive capacity with an AUC of 0.681 (95% CI 0.610-0.751), followed by the CROES with 0.667 (95% CI 0.595-0.738), the STONE with 0.654 (95% CI 0.579-0.728) and finally the GSS with 0.626 (95% CI 0.555-0.698). The stone surface as a single variable had an AUC of 0.641 (95% CI 0.565-0.718). As for complications, the S-ReSC had the highest AUC with 0.664 (95% CI 0.57-0.758), followed by STONE with 0.663 (95% CI 0.572-0.755), GSS with 0.626 (95% CI 0.555).-0.698) and CROES with 0.614 (95% CI 0.518-0.7). The stone surface alone had an AUC of 0.616 (95% CI 0.522-0.715).

CONCLUSION

The nephrolithometry scales analyzed show a moderate predictive capacity for success and complications in patients undergoing PCNL in our center. Moreover, stone surface as an independent variable demonstrates moderate predictive capacity for both outcomes.

Acute liver injury and contralateral pleural effusion as two rare complications following percutaneous nephrolithotomy: a case report

INTRODUCTION

Percutaneous Nephrolithotomy (PCNL) is a widely used surgical intervention for removing large and complex renal calculi. While considered a safe and effective procedure, it can still lead to severe and rare complications, including bleeding, pulmonary complications, and liver dysfunction.

CASE PRESENTATION

This case report presents a case who underwent PCNL for a kidney stone and subsequently developed a series of rare and severe complications. Following the PCNL procedure, the patient experienced significant bleeding, a known but uncommon complication of PCNL, pulmonary complications, a common complication that may carry a risk of death, and acute liver failure, an exceedingly rare consequence of PCNL.

CONCLUSION

In summary, while PCNL is a valuable technique for treating kidney stones, it is not without risk. This case underscores the importance of recognizing and managing rare complications following PCNL surgery, highlighting the need for vigilance, multidisciplinary care, and timely interventions to ensure favorable patient outcomes.

Clinical Utility of S.T.O.N.E, Guy's Scoring System, and Renal Stone Complexity Scoring in Predicting Outcome of Single-Tract Percutaneous Nephrolithotomy

BACKGROUND

Several imaging-based scores have been developed to predict postoperative stone-free state (SFS) and complications. This study aimed to assess the accuracy of the S.T.O.N.E., Guy Scoring System (GSS), and Seoul National University Renal Stone Complexity (S-ReSCS) scores in predicting the outcomes of single-tract percutaneous nephrolithotomy (ST-PCNL). This scoring system holds paramount importance for low-income and low-middle-income countries (LMICs), as it is inexpensive and cost-effective for the healthcare system.

METHODOLOGY

This retrospective study was carried out with 147 participants. Based on the preoperative computerized tomographic (CT) scan, each patient's S.T.O.N.E. score, GSS, and S-ReSCS were recorded. The modified Clavien grading system was used to document intra- and postoperative complications.

RESULTS

The mean age of the sample population was 45 years. SFS was achieved in 110 (74.8%) patients. The number of calyces involved (p = 0.008), S.T.O.N.E. scoring (p = 0.001), GSS (p = 0.008), and S-ReSCS (0.001) correlated well with the SFS. Forty-nine (33.33%) patients developed complications. The most common complications fell within Clavien grade II. No statistical significance was noted between the S.T.O.N.E. score, GSS, and S-ReSCS with the modified Clavien grading system.

CONCLUSION

The S.T.O.N.E. scoring, GSS, and S-ReSCS have a high predictive value for achieving SFS in ST-PCNL. In addition, findings from LMICs are comparable with those from the rest of the world.

Design and internal validation of S.I.C.K.: a novel nomogram predicting infectious and hemorrhagic events after percutaneous nephrolithotomy

BACKGROUND

Hemorrhagic and infectious events represent severe complications after percutaneous nephrolithotomy (PCNLs). Existing nephrolithometric nomograms have been introduced but their reliability in predicting complications is debated. We present a newly designed nomogram with intention to predict hemorrhagic/infectious events after PCNLs.

METHODS

We conducted a multicentric prospective study on adult patients undergoing standard (24 Fr) or mini (18 Fr) PCNL. Dataset was derived from previous RCT, where patients have been assigned to mini-PCNL or standard-PCNL to treat renal stones up to 40 mm. Aim of the study was to identify preoperative risk factors for early postoperative infectious/hemorrhagic complications including fever, septic shock, transfusion or angioembolization.

RESULTS

A total of 1980 patients were finally included. 992 patients (50.1%) received mini-PCNL and 848 standard PCNL (49.9%). The overall SFR was 86.1% with a mean maximum stone diameter of 29 mm (SD 25.0-35.0). 178 patients (8.9%) had fever,14 (0.7%) urosepsis, 24 patients (1.2%) required transfusion and 18 (0.9%) angioembolization. The overall complication was (11.7%). After multivariable analysis, the included elements in the nomogram were age (P=0.041), BMI (P=0.018), maximum stone diameter (P<0.001), preoperative hemoglobin (P=0.005), type 1/2 diabetes (P=0.05), eGFR<30 (P=0.0032), hypertension (>135/85 mmHg, P=0.001), previous PCNL or pyelo/nephrolithotomy (P=0.0018), severe hydronephrosis (P=0.002). After internal validation, the AUC of the model was 0.73.

CONCLUSIONS

This is the first nomogram predicting infections and bleedings after PCNLs, it shows a good accuracy and can support clinicians in their patients' peri-operative workout and management.

Effect of alpha blockers on duration of urinary leakage post-percutaneous nephrolithotomy (PNL): a prospective randomized study

Background

Urinary leakage after removal of the nephrostomy tube post-percutaneous nephrolithotomy (PNL) is a common complication which could be secondary to ureteral stone fragments, blood clots, ureteral edema at the ureteropelvic or ureterovesical junction, or rupture calyx. Unfortunately, it could impact the patient’s hospital stay causing it to be lengthy, delaying time to return to work, and the negative psychological effect. The current study aimed at assessing the role and effectiveness of alpha blockers (tamsulosin) in minimizing the duration of urinary leakage post-percutaneous nephrolithotomy (PNL).

Methods

In this prospective randomized clinical study, 62 cases of PNL were included. Physical examination, laboratory investigations and radiological work up (KUB and plain computed tomography) were done. Cases were randomized into two equal groups: Group A (31 cases) received tamsulosin perioperatively; Group B (31 cases) did not receive tamsulosin. The two groups were followed postoperatively as regards duration of urinary leakage, urinary catheterization and hospital stay.

Results

Duration of urinary leakage was statistically significantly shorter in group A (10.61 ± 6.66 h) compared to group B (21.48 ± 12.41 h) (p-value ˂ 0.001). Similarly, duration of hospital stay was shorter in group A (2.52 ± 0.72 days) compared to group B (3.10 ± 0.98) (p-value 0.020).

Conclusions

In patients undergoing PNL for renal stones and receiving tamsulosin, the duration of urinary leakage, and eventually hospital stay was shorter compared to those not receiving tamsulosin.

Reliability of nephrolithometric nomograms in patients treated with minimally invasive percutaneous nephrolithotomy: A precision study

Objectives

The study aimed to evaluate quality of nephrolithometric nomograms to predict stone-free rates (SFRs) and complication rates (CRs) in case of minimally invasive percutaneous nephrolithotomy (PNL). In the last decade, nomograms have been introduced to estimate the SFRs and CRs of PNL. However, no data are available regarding their reliability in case of utilization of miniaturized devices. Herein we present a prospective multicentric study to evaluate reliability of Guy's stone score (GSS), the stone size, tract length, obstruction, number of involved calyces, and essence of stone (S.T.O.N.E.) nephrolithometry score and Clinical Research Office of the Endourological Society (CROES) score in patients treated with minimally invasive PNL.

Methods

We evaluated SFRs and CRs of 222 adult patients treated with miniaturized PNL. Patients were considered stone-free if no residual fragments of any size at post-operative unenhanced computed tomography scan. Patients demographics, SFRs, and CRs were reported and analyzed. Performances of nomograms were evaluated with the area under the curve (AUC).

Results

We included 222 patients, the AUCs of GSS, CROES score, and S.T.O.N.E. nephrolithometry score were 0.69 (95% confidence interval [CI] 0.61-0.78), 0.64 (95% CI 0.56-0.73), and 0.62 (95% CI 0.52-0.71), respectively. Regarding SFRs, at multivariate binomial logistic regression, only the GSS had significance with an odds ratio of 0.53 (95% CI 0.31-0.95, p=0.04). We did not find significant correlation with complications, with only a trend for GSS.

Conclusion

This is the first study evaluating nomograms in miniaturized PNL. They still show good reliability; however, our data showed lower performances compared to standard PNL. We emphasize the need of further studies to confirm this trend. A dedicated nomogram for minimally invasive PNL may be necessary.

Is Guy's stone score useful for predicting outcomes in percutaneous nephrolithotomy?

INTRODUCTION

Percutaneous Nephrolithotomy (PCNL) is currently the treatment of choice in large kidney stones. Guy's stone score was developed to predict treatment outcomes. The aim of this study was to evaluate the relationship between Guy's score and outcomes in our institution.

MATERIALS AND METHODS

The medical records of patients diagnosed with urolithiasis and treated by PCNL were retrospectively evaluated between January 2017 and December 2018. Analyzed data included: age, sex, Guy's score based on preoperative findings, transfusion, stone-free rate and requirement of auxiliary procedures. Chi-square test was used for the comparison of proportions. Odds ratios (OR) with confidence intervals (CIs) of 95% were calculated by logistic regression.

RESULTS

A total of 386 patients, 53.89% female, mean age of 45.59 ± 15 years were analyzed. Guy's score was as follows: 112 patients (29.04%) were classified as Guy I, 92 patients (23.82%) as Guy II, 94 patients (24.34%) as Guy III, and 88 patients (22.80%) as Guy IV. There were no differences between groups in terms of blood transfusions. Stone-free rate was 96.43% (n = 108) for patients Guy I; 84.78% (n = 72) for Guy II; 76.59% (n = 72) for Guy III and 50% (n = 44) for Guy IV categories (p < 0.0001). Taking as a reference Guy I group, the OR to require new treatment for residual stones were: Guy II 4.85 (CI = 0.95 to 24.60, P = 0.05) to Guy III 8.25 (CI = 1.73 to 39.44, P = 0.008) and Guy IV 27 (CI = 5.84 to 124.70; p < 0.0001).

CONCLUSION

There was a statistically significant association between Guy's Score and stone-free rates following PCNL. Guy's score was useful to predict results of PCNL in our group.

Intravenous Pyelogram (IVP)-Based Guy’s Stone Score (GSS) Utility for Prediction of Outcomes of Upper Pole Access Percutaneous Nephrolithotomy (PCNL)

Background: Renal stone disease is a very common disease, and its lifetime prevalence is 1 - 15%, with a gradual rise in incidence and disease prevalence. There are significant financial implications of its management. Nowadays, for big (typically > 2 cm) renal and upper ureteric stones, PCNL is widely regarded as the first-line treatment. Because most of the intrarenal collecting systems can be accessed by superior calyceal puncture in PCNL, good stone clearance can be achieved. The “Guy’s Stone Score” is a useful technique for categorizing the complexity of PCNL. Objectives: This study aimed to evaluate the role of Guys Stone Score based on KUB and intravenous urography to predict the success rate, grading, and complexity of PCNL, which are performed via the upper pole access. Methods: The present prospective, non-randomized observational study was undertaken in the Department of Urology and Renal transplantation, SCBMCH, Cuttack, from 1st November 2017 to 31st October 2019. A total of 104 patients were enrolled in the study in whom PCNL was performed through superior calyceal puncture, based on preoperative intravenous pyelogram. The Guy's Stone Score was calculated, and the complexity of the procedure was graded using radiological studies, then the outcome was determined accordingly. Results: In this study, 59.6% of the patients had immediate success among them 29.0% had grade 3, and 6.5% had grade 4 GSS. Moreover, 38.4% of the patients had clinically significant residual fragments among them, 75.0% had grade 4, and 20.0% had grade 3 GSS.23% of the patients underwent REDO-PCNL and 11.5% of the patients underwent necessary procedure of ESWL. Conclusions: The present study shows that an intravenous pyelogram-based Guy’s Stone Score (GSS) is an easy-to-use tool in predicting the early success rate and potential difficulties and complications in PCNL performed through superior calyceal puncture.

Evaluation of various nephrometric scoring system for nephrolithiasis to predict stone free status after percutaneous nephrolithotomy: A comparative study

BACKGROUND

The CROES Nephrolithometry nomogram, S.T.O.N.E. Nephrolithometry Score and Guy's stone score were introduced for stratification of kidney stones disease on the basis of quantitative stone burden and its distribution. Till date there has been very limited data on head to head comparison of the existing scoring systems. Comparison and analyses among the scoring system helps in further refinement of these systems along with development of new more effective and broadly acceptable nomogram.

OBJECTIVE

Predictability of the stone-free status (SFS) and post-operative complication after PCNL by various scoring systems (The CROES nomogram, S.T.O.N.E. nephrolithometry score and Guy's stone score).

MATERIALS AND METHODS

Total 100 adult patients underwent PCNL after considering inclusion and exclusion criteria. All patients underwent Preoperative NCCT scan, investigations of blood (Hb%, PCV, bleeding and coagulation profile, urea, and creatinine), and urine (RE/ME and C/S), Postoperative X ray KUB/NCCT.

RESULTS

ROC curves were developed for each scoring system to determine the accuracy to predict stone free status. We found CS had significantly higher AUC than other scoring systems [p-value for CS vs GSS = 0.0091 & CS vs SS = 0.000]. So CS has higher accuracy to predict stone free status. None of the scoring system had shown significantly higher AUC than other scoring system in predicting complication.

CONCLUSION

CROES Nephrolithometry nomogram is most accurate to predict preoperative stone-free rate. All scoring systems can equally predict perioperative complications and other variables.

Role of Preoperative Renal Stone Complexity Assessment by Guy's Stone Score as a Predictor of Percutaneous Nephrolithotomy Outcomes

INTRODUCTION

Various nephrolithometric scoring systems have recently emerged to predict the outcomes of percutaneous nephrolithotomy (PCNL). However, there is no consensus upon an ideal tool. The current study aimed to assess the correlation between Guy's stone score (GSS) and PCNL outcomes.

METHOD

This was a hospital-based observational study of 2-year duration. All patients electively undergoing PCNL for renal stones during the study period were included. Based on the imaging findings, the stones were categorized as simple (GSS I &amp; II) and complex (GSS III &amp; IV). The association between GSS and duration of the procedure, the number of percutaneous tracts needed, stone-free rate (SFR), and the severity of complications based on modified Clavien classification and postoperative stay were assessed.

RESULTS

Total number of the patients studied were 100 (n = 100), and most of the patients were in the category of GSS II (51%). Post-extrapolation of χ2 to Pearson's test, GSS demonstrated a significant association with duration of surgery, the number of percutaneous tracts needed, the severity of complications, and SFR.

CONCLUSIONS

Preoperative assessment of stone complexity by using GSS effectively correlated with SFR as well as other PCNL outcomes. Hence, we recommend utilizing this predictive tool for standardized documentation, preoperative planning, and better patient counseling.

Efficacy of Intercostal Nerve Block for Pain Control After Percutaneous Nephrolithotomy: A Systematic Review and Meta-Analysis

Background: We aimed to assess the efficacy of intercostal nerve block (ICNB) for pain relief after percutaneous nephrolithotomy (PCNL).

Methods: An electronic search of the databases of PubMed, Science Direct, BioMed Central, CENTRAL, Embase, and Google Scholar was conducted. All types of studies conducted on adult patients undergoing PCNL, comparing ICNB with control or any other anesthetic method, and reporting postoperative pain outcomes were included.

Results: Six studies were included. Studies compared ICNB with peritubal (PT) infiltration and with control. Pooled analysis of ICNB vs. PT infiltration indicated no difference between the two groups for pain scores at 6–8 h (MD −0.44; 95% CI −3.41, 2.53; I² = 99%; p = 0.77), 12 h (MD −0.98; 95% CI −4.90, 2.94; I² = 99%; p = 0.62) and 24 h (MD 0.16; 95% CI −0.90, 1.21; I² = 88%; p = 0.77). Time for first analgesic demand was also not significantly different between the two groups. Meta-analysis of ICNB vs. control indicated statistical significant difference in pain scores between the two groups at 8 h (MD −1.55; 95% CI −2.60, −0.50; I² = 47%; p = 0.04), 12 h (SMD −2.49; 95% CI −4.84, −0.13; I² = 96%; p = 0.04) and 24 h (SMD −1.22; 95% CI −2.12, −0.32; I² = 88%; p = 0.008). The total analgesic requirement in morphine equivalents was not significantly different between the two groups.

Conclusions: ICNB may be effective in reducing postoperative pain after PCNL. However, its efficacy may not be greater than PT infiltration. Current evidence is from a limited number of studies. Further, high-quality randomized controlled trials are needed to provide robust evidence.

Multitract percutaneous nephrolithotomy in the management of staghorn stones

Background

Staghorn stones are difficult to manage with a risk of significant renal impairment and urosepsis. Percutaneous nephrolithotomy is the first-line treatment for staghorn stones. Often, multiple access tracts are needed to render the patient stone-free. PCNL has been combined with SWL, flexible URS (ECIRS), and mini-PCNL to access residual fragments without the need of additional tracts. However, in a country with limited access to technology and a restraint on resources, multitract PCNL still is the preferred option. The aim of this study was to assess the safety and efficacy of multitract PCNL in such an environment.

Methods

We analyzed data on sixty-five patients with staghorn calculus who underwent multitract PCNL for a staghorn calculus. Data included demographics, stone parameters, intraoperative parameters, complications and clinical outcomes. Hb-drop and creatinine changes were assessed pre- and post-OP. Complications were graded according to the modified Clavien-Dindo classification.

Results

In a total of 65 patients [47 males (72%)], 154 percutaneous access tracts were used in 66 renal units. The number of tracts varied between 2 and 4 in a single renal unit. The stone-free rate was 85%. 20% of patients developed grade I, 14% grade II, and 3% grade III b complications. There were no grade IV and V complications.

Conclusion

Multitract PCNL is safe and efficient, with a good stone-free rate and an acceptable complication rate. When auxiliary combination treatments are not available, multitract standard PCNL remains an option.

Preoperative risk factors for complications of percutaneous nephrolithotomy

This study was conducted to evaluate preoperative risk factors for development of complications of percutaneous nephrolithotomy (PCNL). All consecutive patients aged ≥ 16 years who underwent PCNL during 2015 were retrospectively reviewed. Non-contrast CT (NCCT) was performed for all patients to evaluate stone complexity. The technique of PCNL was the same for all patients. Intra-operative and postoperative complications were recorded and classified based on modified Clavien system. The differences in preoperative data (patients, renal and stone characteristics including Guy's and STONE scores) between complicated and uncomplicated cases were compared using univariate and multivariate statistical analyses for detection of independent risk factors. The study included 1178 patients (61% were males). Mean age was 50 ± 12 years, and mean BMI was 30.7 ± 5.7 kg/m². Complicated group included 166 patients (14.1%). Independent risk factors on multivariate analysis were infected preoperative urine culture (RR: 2.098, P 0.001, 95%CI: 1.380-3.189), largest stones diameter 30 mm or more (RR: 2.481, P > 0.001, 95%CI: 1.697-3.627) and number of calyces affected by the stones (RR: 2.431, P 0.002, 95%CI: 1.400-4.222 for affection of two calyces and RR: 2.778, P 0.005, 95%CI: 1.357-5.684 for affection of three calyces). While two scoring systems (Guy's and STONE) were not predictive of complications after PCNL, preoperative risk factors were infected preoperative urine culture, distribution of the stones or stone branches in two or three calyceal groups and stone size 30 mm or more.

Guy's Stone Score as a Predictor for Stone-Free Rate and Complications in Percutaneous Nephrolithotomy: A Single-Center Report from a Stone Belt Country

OBJECTIVES

To evaluate Guy's Stone Score (GSS) as a grading system for the complexity of renal calculi before percutaneous nephrolithotomy (PCNL) and as a predictor for stone-free rate (SFR) and potential complications in the setting of a developing country with many cases of advanced complex stone disease.

PATIENTS AND METHODS

We performed a prospective study on 115 patients with renal stones who had PCNL between August 2017 and October 2018. Stone complexity was classified according to GSS using preoperative imaging. The rates of perioperative complications were assessed using the Clavien grading system, and the SFR was assessed in the 3rd postoperative week by abdominal X-ray and renal ultrasound. The χ2 and one-way ANOVA tests were used for statistical analysis. A p value ≤0.05 was considered significant.

RESULTS

The study included 115 patients (77 males) with a mean age of 50.2 (±13.3) years. Cases were classified according to GSS into 4 grades; there were 24 (20.9%) grade I, 48 (41.7%) grade II, 25 (21.7%) grade III, and 18 (15.7%) grade IV cases. There was a significant inverse correlation between GSS grade and SFR (p < 0.001). The rate of complications using the Clavien grading system were significantly higher in GSS grades III and IV (p = 0.002). So were the rates of blood transfusion, the need for >1 access tract, and the duration of hospitalization.

CONCLUSION

GSS is a simple and easily reproducible system to classify the complexity of renal stones. In our setting, it also proved an excellent tool to predict SFR, perioperative complications, and associated ancillary procedures. Ultimately, it can help surgeons and, above all, patients to make a more informed decision about their surgery.

Inter-observer variability amongst surgeons and radiologists in assessment of Guy's Stone Score and S.T.O.N.E. nephrolithometry score: A prospective evaluation

Objective

(a) To assess the inter-observer variability amongst surgeons performing percutaneous nephrolithotomy (PCNL) and radiologists for the Guy’s Stone Score (GSS) and S.T.O.N.E. (stone size [S], tract length [T], obstruction [O], number of involved calyces [N], and essence or stone density [E]) nephrolithometry score; (b) To determine which scoring system of the two is better for predicting the stone-free rate (SFR) after PCNL.

Patients, subjects and methods

Patients undergoing PCNL between February 2016 and September 2016 were prospectively enrolled. Preoperative computed tomography was done in all patients. The GSS and S.T.O.N.E. nephrolithometry score were independently calculated by eight surgeons and four radiologists. The patients were operated on by one of the surgeons (all were consultants). The Fleiss’ κ coefficient was used to assess agreement independently between the surgeons and radiologists. Receiver operating characteristic (ROC) curves were constructed for predicting the SFR using the average of the scores of the surgeons and radiologists separately.

Results

A total of 157 patients underwent PCNL. The SFR was 71.3% (112/157 patients). The Fleiss’ κ scores ranged from 0.51 to 0.88 (overall 0.79) for the S.T.O.N.E. score and 0.53–0.91 for the GSS, suggesting moderate to very good agreement. The ROC curve for the S.T.O.N.E. nephrolithometry scores of surgeons (area under the curve [AUC] = 0.806) as well as the radiologists (AUC = 0.810) had a higher predictive value for the SFR than the GSS of the surgeons (AUC = 0.738) and the radiologists (AUC = 0.747).

Conclusion

There is overall good agreement between surgeons and radiologists for both the GSS and S.T.O.N.E. nephrolithometry score. The S.T.O.N.E. score had a higher predictive value for the SFR than the GSS.

Abbreviations

AUC: area under the curve; GSS: Guy’s Stone Score; KUB: kidneys, ureters and bladder; NCCT: non-contrast CT; PCNL: Percutaneous nephrolithotomy; ROC: receiver operating characteristic; SFR: stone-free rate; S.T.O.N.E.: stone size [S], tract length [T], obstruction [O], number of involved calyces [N], and essence or stone density [E]

Predictive ability of Guy's stone score in pediatric patients undergoing percutaneous nephrolithotomy

BACKGROUND

Several authors have evaluated, in a number of external validation and predominantly adult studies, Guy's stone score (GSS) as a predictive tool for the assessment of stone clearance after percutaneous nephrolithotomy (PCNL). However, there are limited and conflicting data investigating whether GSS could be a potential independent factor associated with residual stone rates and complications of PCNL for children.

OBJECTIVE

The aim of the current study was to evaluate the ability of GSS, as an independent factor, to predict residual stone rates and complications in pediatric patients undergoing PCNL.

STUDY DESIGN

The records of the pediatric patients who had undergone PCNL for stone disease at the current department were retrospectively reviewed. Variables included patient, stone, and treatment parameters. The GSS was used for assessment of stone complexity. Univariate and multivariate analyses were performed to evaluate factors associated with residual stone rates and complications of pediatric PCNL.

RESULTS

The study group consisted of 114 children (63 boys and 51 girls) with a median (interquartile range) age of 6 (3-11) years and who had undergone 122 PCNLs (eight bilateral). Multivariate logistic regression analysis (Summary Table) demonstrated that the independent risk factors for increased residual stone rate following pediatric PCNL monotherapy were GSS (OR 3.14, 95% CI 1.31-7.49, P = 0.01) and number of calyces involved (OR 4.02, 95% CI 1.11-14.53, P = 0.033). Multivariate logistic regression analysis demonstrated that the independent risk factors for complications following pediatric PCNL were surgical experience (OR 2.72, 95% CI 1.09-6.82, P = 0.032), and operation time (OR 1.01, 95% CI 1.00-1.03, P = 0.040).

DISCUSSION

A prediction model is needed to pre-operatively counsel patients and evaluate outcomes for measuring treatment success of PCNL. The GSS provides a simple, reliable and reproducible tool for describing the complexity of PCNL while predicting postoperative stone-free status, despite its limitations. However, little research has been conducted on the applicability of GSS in pediatric patients undergoing PCNL. In addition, conflicting results have been reported about its association with complications of pediatric PCNL.

CONCLUSIONS

The current study found that although GSS had a significant predictive ability for residual stone rates after pediatric PCNL revealed by multivariate logistic regression, the results did not conclude that complexity of GSS was directly proportional to complications of pediatric PCNL. The factors, including calyceal involvement and surgeon experience, may need to be incorporated in GSS to further improve its ability to predict outcomes of pediatric PCNL.

IRB APPROVED PROTOCOL NUMBER

1422.

Do 3D-calculated volume distribution of a stone in pelvicalyceal system affect complications of percutaneous nephrolithotomy?

In our study, we examined the effect of the three-dimensional (3D) stone segmentation volume and its ratio to the renal collecting system on complication rates. Data from141 patients who underwent PCNL surgery were analyzed retrospectively. Volume segmentation of both the renal collecting system and stones was obtained from 3D segmentation software with the images on CT data. After creation of a 3D surface volume rendering of renal stones and the collecting system, segmentation of the renal collecting system volume (RCSV) and analyzed stone volume (ASV) was analyzed and the ASV-to-RCSV ratio was calculated. Univariate analysis and multivariate logistic regression model were used to determine factors that affected complication status. Diagnostic value for the prediction of complication rates was analyzed using receiver operating characteristic (ROC) incline. Overall, there were 141 (92 male and 49 female) eligible patients included in the current study. The overall complication rate for PCNL monotherapy was 31.9%. Multivariate regression analysis (forward stepwise) revealed that the ASV-to-RCSV ratio and number of tracts were independent risk factors for developing complications (OR 1.17, p < 0.001; OR 7.87, p = 0.002; respectively). The ROC analysis revealed a cut-off value of 16.23% (AUC 0.869, p < 0.001, sensitivity 93.3%, specificity 78.1%) for the ASV-to-RCSV ratio. The distribution of stone burden volume in the pelvicalyceal system, which is calculated as a numerical value using the 3D volume segmentation method, is an important predictor of the complication rate before PCNL. The ASV-to-RCSV ratio as a quantitative value may be an instrument for urologists before surgery to help preoperative planning.

A retrospective analysis of complications of laparoscopic left donor nephrectomy using the Kocak's modification of Clavien-Dindo system

Introduction:

Kocak described a modification of Clavien-Dindo classification system (CDCS) for reporting procedure-related complications in laparoscopic donor nephrectomy (LDN). We used the Kocak modification in grading and reporting the severity of complications in patients who underwent LDN and in evaluating various parameters that predict them.

Methods:

In all, 1430 patients who underwent left LDN from 2000 to 2016 were included in this study. All data was retrospectively collected and analyzed for complications occurring in the postoperative period. All complications were classified according to the four grades of Kocak-modified CDCS.

Results:

124 patients (8.6%) suffered a total of 235 postoperative complications. Most of the complications were Grade I and Grade II (Grade I: 79.5% [n = 187] and Grade II 16.2% [n = 38]), 2.5% of the complications were Grade III (n = 6) and Kocak Grade IVa complications occurred in three patients. There was one death (Grade IVb: 0.4%, overall mortality rate: 0.06%). The incidence of complications was significantly greater for male patients, those with body mass index ≥25 kg/m², and if the operating surgeon had ≤ 1 year of experience in performing LDN surgery.

Conclusion:

LDN is a safe procedure with low morbidity. The rate of complications is 8.6% and most of these complications are of low grade. The use of a standardized system for reporting the complications of LDN allows appropriate comparison between reported data.

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

Objective:

To compare the application time and the capacity of the nomograms to predict the success of Guy's Stone Score (GSS), S.T.O.N.E. Nephrolithometry (STONE) and Clinical Research Office of the Endourological Society nephrolithometric nomogram (CROES) of percutaneous nephrolithotomy (PCNL), evaluating the most efficient one for clinical use.

Materials and Methods:

We studied 48 patients who underwent PCNL by the same surgeon between 2010 and 2011. We calculated GSS, STONE and CROES based on pre-operative non-contrast computed tomography (CT) images and clinical data. A single observer, blinded to the outcomes, reviewed all images and assigned scores. We compared the application time of each nomogram. We used an analysis of variance for repeated measures and multiple comparisons by the Tukey test. We compared the area under the ROC curve (AUC) of the three nomograms two by two to determine the most predictive scoring system.

Results:

The immediate success rate was 66.7% and complications occurred in 16.7% of cases. The average operative time was 122 minutes. Mean application time was significantly lower for the GSS (27.5 seconds) when compared to 300.6 seconds for STONE and 213.4 seconds for CROES (p<0.001). There was no significant difference among the GSS (AUC=0.653), STONE (AUC=0.563) and CROES (AUC=0.641) in the ability to predict immediate success of PCNL.

Conclusions:

All three nomograms showed similar ability to predict success of PCNL, however the GSS was the quickest to be applied, what is an important issue for routine clinical use when counseling patients who are candidates to PCNL.

Rearrangement of the Guy's stone score improves prediction of stone-free rate after percutaneous nephrolithotomy

Objective

We propose a modification of the original Guy's Stone Score (GSS) to hold on 20 % of prognostic discrimination among groups which makes this score a more reliable resource for risk assessment in patients undergoing percutaneous nephrolithotomy (PCNL).

Material and methods

Historical cohort of 126 patients undergoing PCNL from December 2010 to November 2014 was included in the survey. Every patient was classified according to the original GSS. For the new classification of Guy Stone Score (GSS-M) all of the subgroups included in the scale were analyzed individually and then ranked from better to worst according to the postoperative stone- free rates (SFRs). This ranking led us to reclassify all the original subgroups, clustering them in three new categories according to their SFRs as subgroups of good, intermediate and poor prognosis, trying to achieve at least 20% of prognostic discrimination among the groups.

Results

Hundred and twenty-six PCNL procedures were evaluated, but only 124 were included for statistical analysis and classified based on SFR according to the GSS as follows: 76% for grade 1, 71% for grade 2, 55% for grade 3 and 20% for grade 4. The SFRs were also assessed for the GSS-M obtaining the following predictive values as 93%, 67% and 44% for the good, intermediate and poor prognostic groups, respectively. The prognostic difference among the GSS-M groups was always >20% (p<0.05).

Conclusion

The original GSS has limitations to predict SFR because of its poor discrimination power among prognostic groups. This rearrangement improves prediction of SFR and better discriminates risk groups in PCNL.

STONE score versus Guy's Stone Score - prospective comparative evaluation for success rate and complications in percutaneous nephrolithotomy

Purpose

The aim of the current study was to compare Guy's score and STONE score in predicting the success and complication rate of percutaneous nephrolithotomy (PCNL).

Materials and Methods

A total of 445 patients were included in the study between July 2015 and December 2016. The patients were given STONE score and Guy's Stone Score (GSS) grades based on CT scan done preoperatively and intra- and post-operative complications were graded using the modified Clavien grading system. The PCNL were done by a standard technique in prone positions.

Results

The success rate in our study was 86.29% and both the GSS and STONE score were significantly associated with a success rate of the procedure. Both the scoring systems correlated with operative time and postoperative hospital stay. Of the total cases, 102 patients (22.92%) experienced complications. A correlation between STONE score stratified into low, moderate, and high nephrolithometry score risk groups (low scores 4-5, moderate scores 6-8, high scores 9-13), and complication was also found (P = 0.04) but not between the GSS and complication rate (P = 0.054).

Conclusion

Both GSS and STONE scores are equally effective in predicting success rate of the procedure.

Predictability and Practicality of Image-Based Scoring Systems for Patient Assessment and Outcome Stratification During Percutaneous Nephrolithotomy: a Contemporary Update

Preoperative nomograms offer systematic and quantitative methods to assess patient- and stone-related characteristics and their impact on successful treatment and potential risk of complication. Discrepancies in the correlation of perioperative variables to patient outcomes have led to the individual development, validation, and application of four independent scoring systems for the percutaneous nephrolithotomy: Guy's stone score, S.T.O.N.E. nephrolithometry, Clinical Research Office of the Endourology Society nomogram, and Seoul National University Renal Stone Complexity. The optimal nomogram should have high predictive ability, be practically integrated into clinical use, and be widely applicable to urinary stone disease. Herein, we seek to provide a contemporary evaluation of the advantages, disadvantages, and commonalities of each scoring system. While the current data is insufficient to conclude which scoring system is destined to become the gold standard, it is crucial that a nephrolithometric scoring system be incorporated into common practice to improve surgical planning, patient counseling, and outcome assessment.

External Validation and Comparisons of the Scoring Systems for Predicting Percutaneous Nephrolithotomy Outcomes: A Single Center Experience with 506 Cases

BACKGROUND

To validate and compare the stone scoring systems (stone size [S], tract length [T], obstruction [O], number of involved calices [N], and essence or stone density [E] [S.T.O.N.E.], Guy's Stone Score [GSS], Clinical Research Office of the Endourological Society [CROES], and Seoul National University Renal Stone Complexity [S-ReSC]) used to predict postoperative stone-free status and complications after percutaneous nephrolithotomy (PCNL).

METHODS

A total of 567 patients who underwent PCNL for renal stones between January 2012 and August 2015 were included in the recent retrospective study. Sixty-one patients who had not done preoperative CT were excluded from the study. GSS, S.T.O.N.E., S-ReSC, and CROES nephrolithometry scores were calculated for each patient, and their potential association with stone-free status, operative and fluoroscopy time, and length of stay (LOS) was evaluated. Postoperative complications were graded according to the modified Clavien classification, and the correlation of scoring systems with postoperative complications was also investigated.

RESULTS

The mean CROES, S.T.O.N.E., GSS, and S-ReSC scores were 203.7 ± 59.8, 7.52 ± 1.8, 2.08 ± 0.9, and 3.35 ± 2.2, respectively. The overall stone-free rate was 77.9%. All scoring systems were significantly correlated with stone-free status and operation time. While GSS, S.T.O.N.E., and CROES systems were significantly correlated with complication rates (CR), S-ReSC score failed to predict CR. All scoring systems except S.T.O.N.E. were significantly correlated with LOS. CROES and S-ReSC scores were predictive of estimated blood loss (EBL), while GSS and S.T.O.N.E. failed to predict EBL.

CONCLUSIONS

Recent study demonstrated that S.T.O.N.E., GSS, CROES, and S-ReSC scoring systems could effectively predict postoperative stone-free status. Although S-ReSC scoring system failed to predict CR, the rest three scoring systems were significantly correlated with postoperative CR.

Comparison of STONE, CROES and Guy's nephrolithometry scoring systems for predicting stone-free status and complication rates after percutaneous nephrolithotomy in obese patients

In this study, we aim to evaluate the accuracy of STONE (stone size, tract length, obstruction, number of involved calyces, and essence/stone density), Clinical Research Office of the Endourological Society (CROES), and Guy's nephrolithometry scoring systems (NSS) in obese patients. The charts of patients who underwent percutaneous nephrolithotomy (PNL) between June 2008 and June 2016 were retrospectively analyzed. Calculations of the STONE, CROES, and Guy's NSS were performed by a resident who was well informed regarding each NSS. Patients were classified under nine scores according to STONE, four grades according to CROES, and four grades according to Guy's NSS. In total, 248 obese patients were enrolled in the study. Stone size was significantly higher in patients without stone-free status (p = 0.001). In patients who were stone-free and those with residual stones, the mean STONE score was 9.71 and 9.23 (p = 0.160), CROES was 172 and 129 (p = 0.001), and Guy's NSS was 1.67 and 2.75 (p = 0.001). Multivariate regression analysis identified the CROES and Guy's NSS were independent factors for PNL success in obese patients (p = 0.01 and p = 0.01, respectively). The CROES and Guy's NSS showed good accuracy with PNL success (AUC = 0.777 and AUC = 0.844, respectively). None of the three NSS systems were statically associated with a complication rate (p = 0.23 for STONE, p = 0.14 for CROES, and p = 0.51 for Guy's NSS). Our study demonstrated that CROES and Guy's NSS were independent predictors of stone-free rate following PNL in obese patients. Our study also revealed that three of the NSSs were not useful for predicting PNL complications in obese patients.

Comparison of CROES, S.T.O.N.E, and Guy's scoring systems for the prediction of stone-free status and complication rates following percutaneous nephrolithotomy in patients with chronic kidney disease

PURPOSE

To evaluate and compare the accuracy of S.T.O.N.E, Clinical Research Office of the Endourological Society (CROES), and Guy's stone score in patients with chronic kidney disease (CKD) following percutaneous nephrolithotomy (PNL).

METHODS

The charts of patients who had undergone a prone percutaneous nephrolithotomy from June 2006 to June 2016 were retrospectively analyzed. Patients accepted as stage 3 and higher according to chronic kidney disease epidemiology collaboration formula, were enrolled into the study. Calculation of the CROES, S.T.O.N.E, and Guy's scoring system (SS) was made as defined in original papers. Patients were categorized into four scores according to CROES, into nine scores according to S.T.O.N.E, and into four scores according to Guy's SS.

RESULTS

A total of 303 patients fulfilled the study inclusion criteria. The mean preoperative eGFR and creatinine levels were 47 mL/min and 1.55 mg/dL, respectively. In patients who were stone free and those with residual stones, the mean CROES SS was 179 and 137 (p < 0.001), the mean S.T.O.N.E score was 8.8 and 9.9 (p < 0.001), and the mean Guy's SS was 1.8 and 2.4 (p < 0.001), respectively. Multivariate regression analysis revealed CROES SS was the only scoring system, which had a predictive value for PNL outcome in patients with CKD (p = 0.011) and any of three SS were not useful for predicting PNL complications in patients with CKD.

CONCLUSION

Our study demonstrated the CROES SS was the only independent factor in the prediction of PNL outcome in CKD patients. Furthermore, three of the NSSs were not useful for predicting PNL complications in patients with CKD.

Current clinical scoring systems of percutaneous nephrolithotomy outcomes

Percutaneous nephrolithotomy has become the preferred treatment modality for patients with large renal calculi. The technique provides excellent stone clearance, but complication rates are higher than those of minimally invasive techniques, such as ureteroscopy and shockwave lithotripsy. Guy's stone score, S.T.O.N.E. nephrolithometry, the CROES nomogram, and S-ReSC are contemporary scoring systems introduced to provide standardized grading of stone complexity and outcomes of percutaneous stone surgery. Guy's stone score is easy to apply and has been validated in multiple studies. The S.T.O.N.E. score is based on factors determined through CT imaging, which is the currently preferred imaging modality for patients with nephrolithiasis. The CROES nomogram was developed from data in a large multicentre database and has high statistical power. Determination of the S-ReSC score relies on stone location only, providing a simple approach to grading disease complexity. Each system has advantages and disadvantages, but several studies suggest that their ability to predict stone-free rate is comparable. The optimal system should have a high predictive ability, should be simple to use and should be widely applicable. Additional studies are required to evaluate patient clinical factors that influence stone complexity and are predictive of outcomes. A future unified scoring system might incorporate the strengths of each currently available system and optimize care of patients with nephrolithiasis.

Comparison of Guy’s vs S.T.O.N.E. nephrolithometry scoring systems in predicting the success rate of PCNL

Introduction and objective:

The aim of the present study was to compare the accuracy of the Guy’s and S.T.O.N.E. scoring systems in predicting percutaneous nephrolithotomy (PCNL) outcomes.

Methods:

This prospective study was carried out in the Department of Urology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, between August 2013 and September 2015 in collaboration with the Department of Radiodiagnosis and Imaging. A total of 100 cases of renal calculi operated on with PCNL were considered in the study on the basis of CT morphodensitometry. The study was approved by the institute’s ethical committee. Guy’s and S.T.O.N.E. scoring systems were calculated. Regression analysis and ROC curves were performed.

Results:

A total of 100 PCNLs were operated on. The overall stone-free rate was 90% with a complication rate of 17%. When compared to patients with residual fragments, stone-free patients had significantly lower Guy’s grade (3.5 vs 2; p < 0.001) and S.T.O.N.E. score (9.1 vs 7.5; p = 0.023). Logistic regression analysis showed that both Guy’s and S.T.O.N.E. systems were significantly associated with stone-free status, OR 0.96 ( p < 0.001) and OR 0.94 ( p < 0.001), respectively. Furthermore, both scoring systems were significantly associated with estimated blood loss ( p = 0.02 and p = 0.004). There was good correlation between both scoring systems and operative time ( r = 0.2, p < 0.002 and r = 0.3, p < 0.002) and length of hospital stay ( r = 0.1, p = 0.002 and r = 0.2, p < 0.002). There were significant associations between both scoring systems and complications ( p < 0.001 and p = 0.004). There was no significant difference in the areas under the curves for the Guy’s and S.T.O.N.E. scoring systems (0.96 (95% CI 0.92–0.99) vs 0.94 (95% CI 0.89–1.001); p < 0.001).

Conclusion:

Both Guy’s and S.T.O.N.E scoring systems have comparable accuracies in predicting post-PCNL stone-free status. Other factors not included in either scoring system may need to be incorporated in the future to increase their accuracy.

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

Objective

To prospectively compare the Guy’s Stone Score (GSS), S.T.O.N.E. [stone size (S), tract length (T), obstruction (O), number of involved calices (N), and essence or stone density (E)] score and the Clinical Research Office of the Endourological Society (CROES) nephrolithometric nomogram to predict percutaneous nephrolithotomy (PCNL) success rate and assess the correlation with perioperative complications.

Patients and methods

We prospectively evaluated all consecutive PCNL patients at our institute between 1 November 2013 and 31 May 2015. The above scoring systems were applied to preoperative non-contrast computed tomography and the practical difficulties in such applications were noted. Perioperative complications and the stone-free rate (SFR) were also recorded. Receiver operating characteristic curves were drawn and the areas under curves were compared and appropriate statistical analysis done.

Results

In all, 48 renal units were included in the study. The overall SFR was 62.2%. The presence of staghorn stones (β = 27.285, 95% confidence interval 1.19–625.35; P = 0.039) was the only significant variable associated with the residual stones on multivariate analysis. Stone-free patients had significantly lower median GSS (2 vs 4) and S.T.O.N.E. scores (6 vs 10) and higher median CROES scores (83% vs 63%) (all P < 0.001) compared to residual-stone patients. All scoring systems were significantly associated with SFR (all P < 0.001). There was no significant difference in the areas under curves of the scoring systems (0.858, 0.923, and 0.931, respectively). Furthermore, all scoring systems had weak correlations with Clavien–Dindo classified complications (r = 0.29, P = 0.045; r = 0.40, P = 0.005 and r = −0.295, P = 0.04, respectively). We found no standardisation for the measurement of stone dimensions, tract length, Hounsfield units, and staghorn definition.

Conclusions

All scoring systems equally predicted SFR and had a weak correlation with Clavien–Dindo complications. Standardisation is needed for the variables in which they have been found deficient.

Guy's Stone Score (GSS) Based on Intravenous Pyelogram (IVP) Findings Predicting Upper Pole Access Percutaneous Nephrolithotomy (PCNL) Outcomes

Objective. To predict the success rate and complications following percutaneous nephrolithotomy via the upper pole using the Guy's Stone Score (GSS) based on the findings of a preoperative intravenous pyelogram (IVP). Patients and Methods. Two hundred and twenty-seven renal operations, which were carried out using PCNL via the upper pole, were classified according to the GSS assigned. Any complications were classified according to the Clavien classification. The success rates and incidence of any complications were compared between each GSS. Results. The immediate success rates were 87.50% of GSS1, 71.43% of GSS2, 53.62% of GSS3, and 38.46% of GSS4, P < 0.01. There were statistically significant differences between the groups in stone size, overall immediate success rate, operative time, number of access tracts, and frequency of tubeless PCNL. Major complications (a Clavien score of 3-5) were significantly higher in the cases with a higher GSS. Conclusion. A GSS based on an IVP is a simple and reliable tool in predicting the success rate and possible complications following upper pole access PCNL.

Grading of complications of transurethral resection of bladder tumor using Clavien-Dindo classification system

Introduction:

Clavien–Dindo classification system is used for grading complications of various oncological, renal, and endourological procedures. We applied this system for grading the severity of perioperative complications in patients undergoing transurethral resection of bladder tumor (TURBT) and identify parameters predicting these complications.

Materials and Methods:

Data of 984 patients who underwent TURBT from 2006 to 2014 were included in this study. All data was retrospectively collected and analyzed for complications occurring within the first postoperative month. All complications were classified according to the five grades of modified CCS (.Clavien classification system).

Results:

A total of 172 complications were observed in 138 patients. Majority were low grade complications (Grade 1 [77.3%] and Grade 2 [12.7%]). Higher grade complications were rare (Grade 3 [6.4%] and Grade 4 [3.0%]). There was one death (Grade 5 0.6%), with an overall mortality rate of 0.1%. The incidence of complications was significantly greater for age >60 years, baseline serum creatinine >1.4 mg/dl, size of tumor >4 cm, tumor located at dome, resection time >60 min, incomplete resection and if surgery performed by a resident urologist.

Conclusions:

Clavien–Dindo classification system can be easily applied to grade the complications of TURBT, and it is easily reproducible. We observed that TURBT was a safe procedure. Majority of complications were Grade 1–2 (90%) and Grade 3–5 were rare (10%). Postoperative bleeding is the most common complication. A greater rate of complications of TURBT was associated with patient age, size of tumor, location of tumor, surgeon experience, resection time, and completion of tumor resection.

Implications of different nephrolithometry scoring systems on clinical practice of endourologists: An international web-based survey

OBJECTIVES

To assess the implications of different nephrolithometry scoring systems (NLSS) on clinical practice of endourologists to predict stone-free status (SFS) after percutaneous nephrolithotomy (PCNL).

METHODS

A web-based survey was sent to members of the Endourological Society. Demographic and practice pattern data were collected. Multiple-choice and open-ended questions were used to assess awareness about the NLSS and their authentic use in clinical practice. Surgeon preferences and limitations of NLSS and how to overcome them were asked.

RESULTS

In all, there were 162 responses, including 17 (10.5%) respondents who were not aware of NLSS. Most respondents (82.1%) denied the efficacy of NLSS in predicting SFS after PCNL. Of 145 respondents who were aware of NLSS, 85.5% did not use them in clinical practice. Endourologists aged 40-60 years (P < 0.001), in practice for 10-20 years (P = 0.003), those performing 100-200 PCNLs/year (P = 0.02), and those from North America (P < 0.001) seemed to use NLSS more frequently. In all, 50% of respondents preferred not to use any NLSS, while 29% chose the S.T.O.N.E followed by the Guy's Stone Score (10.3%) and The Clinical Research Office of the Endourology Society (CROES) nomogram (8.3%). Inconsistency and variability among different NLSS were the main drawbacks reported by 82% of 89 respondents. The need for high-level evidence for NLSS through direct randomised prospective comparison was recommended by 24.8% of respondents who answered that question.

CONCLUSION

There is a lack of compliance and acceptance of different NLSS in clinical practice among endourologists. Inconsistency and inaccuracy in predicting SFS after PCNL limits their incorporation into clinical practice. However, the results of this study might not be generalisable due to the selection bias resulting from the geographical distribution of the respondents and the heterogeneity in surgical expertise. Therefore, randomised prospective direct comparisons and validation of these systems are recommended.

Risk factors for fever and sepsis after percutaneous nephrolithotomy

Objective

Percutaneous nephrolithotomy (PCNL) is commonly used in the management of large renal stones. Postoperative infections are one of the most common complications of this procedure. The present study is to determine and assess the factors that may increase the risk to develop fever and urinary sepsis after PCNL.

Methods

A total of 60 patients (38 males and 22 females) with a mean age of 40.25 years enrolled in this study in Sulaimania Teaching Hospital. Patients had renal stone disease need operation with different socioeconomic status, body mass index and different type and size of stones were included in this study. Patients with preoperative positive urine culture and sensitivity were excluded. Preoperative investigations done for all patients. All Patients received prophylactic antibiotic gentamicin intravenously at the induction of anaesthesia. Renal pelvis urine sample were taken from all patients after puncturing the pelvicalyceal system and send for culture and sensitivity. Patients were monitored closely in the postoperative period for the development of fever and sepsis.

Results

Mean duration of the operations was 77.08 min ranged 40–120 min. All patients had postoperative nephrostomy tube. Seventeen (28.33%) patients developed post PCNL fever and the statistically significant factors for post PCNL fever were diabetes mellitus (DM) (p = 0.001), stone burden (p = 0.001), number of the stones (p < 0.001), degree of hydronephrosis (p = 0.001), duration of the operation (p < 0.001), residual stones (p = 0.001) and number of tracts (p = 0.038). Three (5.00%) patients developed post PCNL sepsis, and the statistically significant risk factors for post PCNL sepsis were duration of the operation (p = 0.013) and intraoperative blood loss, postoperative drop in haemoglobin (HB) level (p = 0.046).

Conclusion

DM, staghorn stones, degree of hydronephrosis, duration of the operation and number of tracts are risk factors for post PCNL fever, while number of stones, intraoperative blood loss, duration of the operation and residual stones are risk factors for post PCNL sepsis.

Multicenter External Validation and Comparison of Stone Scoring Systems in Predicting Outcomes After Percutaneous Nephrolithotomy

BACKGROUND AND PURPOSE

Several scoring systems have recently emerged to predict stone-free rate (SFR) and complications after percutaneous nephrolithotomy (PCNL). We aimed to compare the most commonly used scoring systems (Guy's stone score, S.T.O.N.E. nephrolithometry, and CROES nomogram), assess their predictive accuracy for SFR and other postoperative variables, and develop a risk group stratification based on these scoring systems.

MATERIALS AND METHODS

We performed a retrospective review of patients who have had a PCNL at four academic institutions between 2006 and 2013. Primary outcome was SFR within 3 weeks of the surgery and secondary outcomes were operative time (OT), complications, and length of stay (LOS). We performed chi-squared, t-test, logistic, linear, and Poisson regressions, as well as receiver operating characteristics curve with area under the curve (AUC) calculation.

RESULTS

We identified 586 patients eligible for analysis. Of these, 67.4% were stone free. Guy's, S.T.O.N.E., and CROES score were predictive of SFR on multivariable logistic regression (odds ratio [OR]: 1.398, 95% confidence interval [CI]: 1.056, 1.852, p = 0.019; OR: 1.417, 85% CI: 1.231, 1.631, p < 0.001; OR: 0.993, 95% CI: 0.988, 0.998, p = 0.004) and have similar predictive accuracy with AUCs of 0.629, 0.671, and 0.646, respectively. On multivariable linear regression, only S.T.O.N.E. was an independent predictor of longer OT (β = 14.556, 95% CI: 12.453, 16.660, p < 0.001). None of the scores were independent predictors of postoperative complications or a longer LOS. Poisson regression allowed for risk group stratification and showed the S.T.O.N.E. score and CROES nomogram to have the most distinct risk groups.

CONCLUSIONS

The three evaluated scoring systems have similar predictive accuracy of SFR. S.T.O.N.E. has additional value in predicting OT. Risk group stratification can be used for patient counseling. Further research is needed to identify whether or not any is superior to the others with regard to clinical usefulness and predictive accuracy.

Nephrolithometric Scoring Systems to Predict Outcomes of Percutaneous Nephrolithotomy

Currently, there is no single agreement upon an ideal predictive model that characterizes the complexity of renal stones and predicts surgical outcomes following percutaneous nephrolithotomy (PCNL). New predictive tools have recently emerged to systematically and quantitatively assess kidney stone complexity to predict outcomes following PCNL: the Guy's Stone Score, the CROES nomogram, S.T.O.N.E. nephrolithometry, and S-ReSC score. An ideal scoring system should include variables that both influence surgical planning and are predictive of postoperative outcomes. This review discusses the strengths, weaknesses, and commonalities of each of the above scoring systems. Additionally, we propose future directions for the development and analysis of surgical treatment for stone disease, namely, the importance of assessing radiation exposure and patient quality of life when counseling patients on treatment options.

Value of preoperative stone scoring systems in predicting the results of percutaneous nephrolithotomy

INTRODUCTION

Guy's Stone Score and S.T.O.N.E. Nephrolithometry nomograms have been introduced for systematic and quantitative assessment of kidney stones. The aim of this study was to reveal the value of two scorings systems, Guy and S.T.O.N.E, most frequently used for predicting postoperative stone-free status prior to Percutaneous Nephrolithotomy (PCNL), in the prediction of postoperative results of PCNL.

MATERIAL AND METHODS

We retrospectively examined patients who underwent PCNL. Preoperative abdominopelvic computerized tomography images of these patients were reviewed and scored according to the Guy and S.T.O.N.E. systems. The relationship between the Guy and S.T.O.N.E. scores, and their postoperative stone-free status, complications based on Clavien system, operation time, fluoroscopy time and period of hospitalization was compared.

RESULTS

We identified a total of 102 patients who underwent PCNL between 2010 and 2014, having met the inclusion criteria. The relationships between the total S.T.O.N.E score and Clavien score (p <0.001); time of operation (p = 0.012) and stone-free status (p <0.001); Guy stone score and Clavien score (p <0.001); and period of hospitalization (p <0.001) and time of operation (p <0.001) were found to be statistically significant. There was no statistically significant relationship between Guy score and stone-free status and no statistically significant relationship was found between fluoroscopy time and both stone scoring systems.

CONCLUSIONS

Guy and S.T.O.N.E. scoring systems may be used as effective instruments particularly for predicting postoperative complications.

Evaluation of stone-free rate using Guy's Stone Score and assessment of complications using modified Clavien grading system for percutaneous nephro-lithotomy

To prospectively evaluate the ability of Guy's Stone Score (GSS) in predicting stone clearance rate and complication rate (by modified Clavien grade) for renal stones treated by percutaneous nephrolithotomy (PNL). From January 2013 to June 2014, a total of 142 patients undergoing PNL were evaluated prospectively. Patients with co-morbidities like hypertension, diabetes, renal failure were excluded from the study. All patients were classified according to GSS based on the findings of pre-operative intravenous urography (IVU) and per-operative retrograde pyelography (RGP). All PNL procedures were done by standard technique in prone position and success was defined as no residual stone visible on X-ray KUB done on the third postoperative day. Complications were classified according to modified Clavien grading system. The initial stone clearance rate was 71.1% and overall final stone clearance rate was 90.14%. The complication rate according to Clavien grading system was 40.1%. The final stone clearance rates were 93.9, 85.71, 90.47, and 77.77% in GSS I, II, III, and IV, respectively (p<0.001, <0.05, <0.05 and >0.05, respectively). The Clavien complication rates were 23, 61, 52, and 77.7% in GSS I, II, III, and IV, respectively (p<0.001). The GSS is a simple and easily reproducible system to preoperatively predict stone-free rate and perioperative complication rate. It helps in better patient counseling preoperatively.

Contemporary assessment of renal stone complexity using cross-sectional imaging

Recently, several scoring systems have been proposed to predict outcomes of percutaneous nephrolithotomy, objectively and quantitatively assessing kidney calculi complexity using cross-sectional imaging. These scoring systems are promising new tools that can guide surgical decision making, predict surgical outcomes, counsel patients undergoing stone surgery, and improve standardized academic reporting in percutaneous kidney stone surgery. In this article, we review features of each of these systems, their similarities and differences, and their applicability in clinical practice and relevance in academic reporting.

Evaluation and comparison of urolithiasis scoring systems used in percutaneous kidney stone surgery

PURPOSE

Contemporary predictive tools for percutaneous nephrolithotomy outcomes include the Guy stone score, S.T.O.N.E. nephrolithometry and the CROES nephrolithometric nomogram. We compared each scoring system in the same cohort to determine which was most predictive of surgical outcomes.

METHODS

We retrospectively reviewed the records of patients who underwent percutaneous nephrolithotomy between 2009 and 2012 at a total of 3 academic institutions. We calculated the Guy stone score, the S.T.O.N.E. nephrolithometry score and the CROES nephrolithometric nomogram score based on preoperative computerized tomography images. A single observer at each institution reviewed all images and assigned scores. Univariate and multivariate analysis was done to determine the most predictive scoring system.

RESULTS

We enrolled 246 patients in study. In stone-free patients vs those with residual stones the mean Guy score was 2.2 vs 2.7, the mean S.T.O.N.E. score was 8.3 vs 9.5 and the mean CROES nomogram score was 222 vs 187 (each p <0.001). Logistic regression revealed that the Guy, S.T.O.N.E. nephrolithometry and CROES nomogram scores were significantly associated with stone-free status (p = 0.02, 0.004 and <0.001, respectively). The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss (p <0.0001 and 0.03) and length of stay (p = 0.03 and 0.009, respectively). The CROES nomogram did not predict estimated blood loss or length of stay.

CONCLUSIONS

All scoring systems and the stone burden equally predicted stone-free status. The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss and length of stay. A single scoring system should be adopted to unify reporting.