Comparing different kidney stone scoring systems for predicting percutaneous nephrolithotomy outcomes: A multicenter retrospective cohort study

Predictive factors of stone-free rate and complications in patients with proximal impacted ureteral stones undergoing percutaneous nephrolithotomy: based on a new scoring standard

To evaluate the predictive factors affecting the stone-free rate (SFR) and complications of percutaneous nephrolithotomy (PCN) in the treatment of proximal impacted ureteral stones (PIUS) based on a new scoring standard. The data of 90 patients with PIUS were collected in this retrospective study between January 2015 and June 2023. Univariate and multivariate logistic regression analyses were used to determine factors affecting treatment outcome in terms of SFR and complications. The scoring standard for patients with PIUS was developed based on the univariate logistic regression analyses. In the univariate analysis, stone density (P = 0.015), and stone diameter (P = 0.032) significantly were associated with lower SFR. And degree of hydronephrosis (P = 0.014), Preoperative infection (P = 0.002), and history of lithotripsy (P = 0.045) were associated with occurrence of complications. Multivariate analysis indicated that stone density (P = 0.020), and stone diameter (P < 0.001) were associated with lower SFR; independent risk factors for development of complications were history of lithotripsy (P = 0.024), and preoperative infection (P < 0.001). Additionally, score ≥ 3 was the independent risk factor for both SFR (P < 0.001) and complication rate (P < 0.001). Subgroup analysis shown that there were statistically significant differences between the two groups in terms of stone-free rate (P = 0.032) and complications (P = 0.015). According to the findings of this study, the stone score ≥ 3 was determined as a critical predictive factor of SFR and complications in PIUS patients undergoing PCN based on a new scoring standard. Additionally, PCN has high initial SFR and low complications when dealing with score < 3 PIUS.

Comparison of percutaneous nephrolithotomy and flexible ureterorenoscopy in the treatment of single upper ureteral calculi measuring 1 to 2 centimeters: a retrospective study

PURPOSE

To compare the efficacy and safety of micropercutaneous nephrolithotomy (MPCNL) and flexible ureteroscopy (FURS) in the treatment of single upper ureteral calculi measuring 1 to 2 centimeters.

METHODS

This study is a retrospective analysis that combines a review of medical records with an outcomes management database. A total of 163 patients who underwent MPCNL and 137 patients who had FURS were identified between January 2017 and December 2021. Demographic data, operation time, hospitalization time, stone-free rate, and complication rate were collected and analyzed.

RESULTS

Preoperative general data of sex, age, BMI, serum creatinine, time of stone existence, stone hardness, stone diameter, preoperative hydronephrosis, and preoperative infection of the MPCNL group have no statistically significant difference with that of the FURS group. All MPCNL or FURS operations in both groups were successfully completed without any instances of reoperation or conversion to another surgical procedure. Patients who underwent MPCNL had a considerably reduced operation time (49.6 vs. 72.4 min; P<0.001), but a higher duration of hospitalization (9.1 vs. 3.9 days; P<0.001) compared to those who underwent FURS. The stone-free rate in the MPCNL group was superior to that of the FURS group, with a percentage of 90.8% compared to 71.5% (P<0.001). There was no statistically significant disparity in the rate of complications between the two groups (13.5% vs. 15.3%; P = 0.741).

CONCLUSION

Both MPCNL and FURS are viable and secure surgical choices for individuals with solitary upper ureteral calculi measuring 1 to 2 cm. The FURS procedure resulted in a shorter duration of hospitalization compared to MPCNL. However, it had a comparatively lower rate of successfully removing the stones and required a longer duration for the operation.There were no substantial disparities observed in the complication rate between the two groups.FURS is the preferable option for treating uncomplicated upper ureteral calculi, whereas MPCNL is the preferable option for treating complicated upper ureteral calculi.Prior to making treatment options, it is crucial to take into account the expertise of surgeons, the quality of the equipment, and the preferences of the patient.

TRIAL REGISTRATION

No.

Assessment of Hounsfield Units and Factors Associated with Fragmentation of Renal Stones by Extracorporeal Shock Wave Lithotripsy: A Computerized Tomography Study

The success rate of extracorporeal shock wave lithotripsy (ESWL) is influenced by various factors, including stone density, and is determined through computed tomography scans in terms of Hounsfield units (HU).

MATERIALS AND METHODS

This retrospective single-center study was conducted in the King Fahad Hospital. Sixty-seven adult patients with renal and ureteric stones were selected randomly and enrolled in the study. Their ages ranged from 20 to 69 years. The patients were examined with non-contrast enhancement (NCCT) to assess the HU of their stones and were consequently treated with ESWL.

RESULTS

Of the 67 patients, 37.3% had stones that were completely fragmented, while 62.7% had stones that were partially fragmented. The HU, location of the stone, multiplicity of the stone, and patient age were found to be significant factors contributing to stone fragility (p-values < 0.05). The HU data were found to have a positive significant linear correlation with serum calcium (r = 0.28, p-value = 0.036), while serum acid had a negative correlation (r = -0.55, p-value < 0.001). Thus, the probability of calcium-containing stone formation increases with increased HU. In contrast, uric acid stone formation likely develops with decreasing HU with serum uric acid. Renal stones in patients with diabetes mellitus and hypertension were not completely fragmented compared to those without clinical history.

CONCLUSIONS

Mean HU, location of the stone, laterality, stone status, and the number of ESWL sessions are the most significant factors affecting stone fragility. CT attenuation values can predict the composition of stones from serum calcium and uric acid examinations. Hypertension and diabetes mellitus are risk factors for renal stone fragmentation.

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.

Evaluation of the efficacy of ureteroscopic lithotripsy for proximal impacted ureter stones based on a new scoring standard: a bicentric matched-pair analysis

OBJECTIVE

To evaluate the clinical efficacy of ureteroscopic lithotripsy (URSL) in the treatment of proximal impacted ureter stones (PIUS) based on a new scoring standard in two medical centers.

METHODS

The data of 45 patients with Complicated PIUS (total stone score ≥ 3) and 350 with Simple PIUS (total stone score < 3) who underwent URSL were collected in this retrospective study between January 2015 and June 2022. The definition and scoring standards for preoperative high-risk factors associated with stones included whether the diameter of the stone was > 2 cm, stone density was > 1000 HU, there was a history of lithotripsy, the degree of hydronephrosis was greater than moderate, and there was an infection. Scores for stones were then assigned (yes = 1, no = 0), and the Complicated stone case was defined as a total stone score ≥ 3; the Simple stone case was defined as a total stone score < 3. During the same period, 45 patients were selected from the patients with Simple stone cases as the control group, matched at a 1:1 ratio to index Complicated stone cases with regard to age, sex, and BMI. Perioperative data were compared between the two groups.

RESULTS

All 90 operations were successfully completed. Compared to the Simple cases group, the surgical duration of the Complicated group was significantly longer (59.69 ± 28.06 min vs. 73.46 ± 27.12 min, p < 0.05), and stone-free rate (SFR) was significantly lower (88.89 vs. 68.9%, p < 0.05). There was a significant difference in complication rate between the two groups regarding Clavien grade I, II, or III complications (20.0% in Complicated cases group vs. 8.9% in Simple cases group, p = 0.037). As for the length of the hospital stay and the total treatment cost, the two groups have no difference.

CONCLUSION

For Simple stone cases, URSL had a better SFR and higher surgical efficacy, whereas complicated stone cases had a high complication rate and long operation time. Thus, we suggest that URSL is the preferred choice for Simple stone cases rather than complicated stone cases.

High stone-free rate immediately after suctioning flexible ureteroscopy with Intelligent pressure-control in treating upper urinary tract calculi

Background

The retrospective observational study aimed to evaluate the safety and efficacy of suctioning flexible ureteroscopy with Intelligent pressure-control (SFUI) on treating upper urinary tract calculi in a large cohort.

Methods

Between July 2020 and August 2021, 278 patients with upper urinary tract calculi who underwent SFUI in our hospital were enrolled. Outcomes were stone-free rate (SFR) in one session and one-month after SFUI treatment, and complications scored by the Clavien-Dindo classification.

Results

A total of 310 kidneys underwent SFUI were included. The median surgery time was 75 min (ranged 60–110 min). One session and one-month SFRs were 80.65% and 82.26%, respectively. The one-session SFR was ≧ 87% in patients with Guy’s stone score of Grade I among stone size < 40 mm. Risk factors for unsuccessful stone-free in one session were stone history (adjusted odds ratio (aOR): 2.39, 95% confidence interval (CI): 1.21–4.73), stone size of 40–49 mm (aOR: 4.37, 95% CI: 1.16–16.45), Guy’s stone score ≧ Grade II (Grade II, aOR: 3.54, 95% CI: 1.18–10.59; Grade III, aOR: 10.95, 95% CI: 2.65–45.25). The incidence of Clavien-Dindo grade II-III complication was 3.26%. Complication is associated with Guy’s stone score III (aOR: 22.36, 95% CI: 1.81–276.36).

Conclusion

SFUI shows good safety and efficiency on treating upper urinary tract calculi. Patients with stone size < 40 mm or Guy’s stone score of Grade I have a high chance to reach stone-free after SFUI treatment.

Current status of nomograms and scoring systems in paediatric endourology: A systematic review of literature

INTRODUCTION

The incidence of paediatric kidney stone disease is increasing worldwide, with the requirement for endourological interventions mirroring this. Multiple nomograms, grading tools and scoring systems now exist in the adult setting, which aim to enhance the pre-operative planning and decision-making associated with these surgeries. In recent years, there has been increasing interest in nomograms dedicated for use in the paediatric setting. This study provides an up-to-date review and assessment of available paediatric endourology nomograms and scoring systems.

METHODS

A comprehensive search of worldwide literature was conducted according PRISMA methodology. Studies describing paediatric-specific endourology nomograms, scoring systems or grading tools and studies externally validating these tools, or existing adult tools in a paediatric population, were evaluated and included in the narrative data synthesis.

RESULTS

A total of 7 endourology nomograms were identified. 4 were paediatric-specific, 2 for shockwave lithotripsy, 1 for percutaneous nephrolithotomy or ureteroscopy and 1 for percutaneous nephrolithotomy specifically. Only the 2 shockwave lithotripsy nomograms have been externally validated in 4 further studies and showed efficacy in predicting treatment success. 3 adult tools, all specific to PCNL have been investigated and validated in a paediatric setting in 11 studies. In general, they showed efficacy in the prediction of stone free rate but were poor at predicting likelihood of complications.

CONCLUSION

A limited number of paediatric-specific endourology predictive nomograms are available to aid in the management of kidney stone disease, with the strongest evidence supporting those designed for shockwave lithotripsy. Although 3 adult tools have been implemented, there are problems applying these to the paediatric setting and further development of paediatric-specific tools is necessary.

A deep learning system for automated kidney stone detection and volumetric segmentation on noncontrast CT scans

PURPOSE

Early detection and size quantification of renal calculi are important for optimizing treatment and preventing severe kidney stone disease. Prior work has shown that volumetric measurements of kidney stones are more informative and reproducible than linear measurements. Deep learning-based systems that use abdominal noncontrast computed tomography (CT) scans may assist in detection and reduce workload by removing the need for manual stone volume measurement. Prior to this work, no such system had been developed for use on noisy low-dose CT or tested on a large-scale external dataset.

METHODS

We used a dataset of 91 CT colonography (CTC) scans with manually marked kidney stones combined with 89 CTC scans without kidney stones. To compare with a prior work half the data was used for training and half for testing. A set of CTC scans from 6185 patients from a separate institution with patient-level labels were used as an external validation set. A 3D U-Net model was employed to segment the kidneys, followed by gradient-based anisotropic denoising, thresholding, and region growing. A 13 layer convolutional neural network classifier was then applied to distinguish kidney stones from false positive regions.

RESULTS

The system achieved a sensitivity of 0.86 at 0.5 false positives per scan on a challenging test set of low-dose CT with many small stones, an improvement over an earlier work that obtained a sensitivity of 0.52. The stone volume measurements correlated well with manual measurements (r 2 = 0.95 $r^2 = 0.95$ ). For patient-level classification, the system achieved an area under the receiver-operating characteristic of 0.95 on an external validation set (sensitivity = 0.88, specificity = 0.91 at the Youden point). A common cause of false positives were small atherosclerotic plaques in the renal sinus that simulated kidney stones.

CONCLUSIONS

Our deep-learning-based system showed improvements over a previously developed system that did not use deep learning, with even higher performance on an external validation set.

The clinical efficacy of novel vacuum suction ureteroscopic lithotripsy in the treatment of upper ureteral calculi

OBJECTIVE

To investigate the clinical efficacy of a novel vacuum suction ureteroscopic approach in the treatment of upper ureteral calculi and to compare it with traditional rigid and flexible ureteroscopic approaches.

SUBJECTS AND METHODS

A total of 160 patients with impacted upper ureteral calculi were included in this study. 50 patients underwent rigid ureteroscopic lithotripsy, 54 patients underwent flexible ureteroscopic lithotripsy, and 56 patients underwent vacuum suction ureteroscopic lithotripsy. The operative time, length of hospitalization, stone-free rate, the incidence of postoperative complications, and total treatment cost were compared among the three groups. Subgroup analysis was performed based on the stone diameter over and below 1.5 cm.

RESULTS

All operations were performed successfully, and there were no cases converted to open surgery. Compared with the other 2 groups, the vacuum suction ureteroscopy group had a higher stone-free rate at 3-5 days (90.0% vs. 61.9% vs. 55.6%, P < 0.05) and 1 month (96.4% vs. 77.7% vs. 74.0%, P < 0.05) postoperatively. In subgroup analysis, the stone-free rate of the vacuum suction ureteroscopy group was significantly higher when the stone diameter was > 1.5 cm at 1 month postoperatively (P < 0.05) compared with that in the other 2 groups; however, there were no differences in postoperative complications. (P > 0.05).

CONCLUSION

The novel vacuum suction ureteroscopic lithotripsy has significantly improved the stone-free rate especially in complicated cases, compared with that in rigid and flexible approaches; however, the complication and cost were not increased.