Extracorporeal shock wave lithotripsy versus flexible ureterorenoscopy in the treatment of untreated renal calculi

Stone decision engine accurately predicts stone removal and treatment complications for shock wave lithotripsy and laser ureterorenoscopy patients

Kidney stones form when mineral salts crystallize in the urinary tract. While most stones exit the body in the urine stream, some can block the ureteropelvic junction or ureters, leading to severe lower back pain, blood in the urine, vomiting, and painful urination. Imaging technologies, such as X-rays or ureterorenoscopy (URS), are typically used to detect kidney stones. Subsequently, these stones are fragmented into smaller pieces using shock wave lithotripsy (SWL) or laser URS. Both treatments yield subtly different patient outcomes. To predict successful stone removal and complication outcomes, Artificial Neural Network models were trained on 15,126 SWL and 2,116 URS patient records. These records include patient metrics like Body Mass Index and age, as well as treatment outcomes obtained using various medical instruments and healthcare professionals. Due to the low number of outcome failures in the data (e.g., treatment complications), Nearest Neighbor and Synthetic Minority Oversampling Technique (SMOTE) models were implemented to improve prediction accuracies. To reduce noise in the predictions, ensemble modeling was employed. The average prediction accuracies based on Confusion Matrices for SWL stone removal and treatment complications were 84.8% and 95.0%, respectively, while those for URS were 89.0% and 92.2%, respectively. The average prediction accuracies for SWL based on Area-Under-the-Curve were 74.7% and 62.9%, respectively, while those for URS were 77.2% and 78.9%, respectively. Taken together, the approach yielded moderate to high accurate predictions, regardless of treatment or outcome. These models were incorporated into a Stone Decision Engine web application (http://peteranoble.com/webapps.html) that suggests the best interventions to healthcare providers based on individual patient metrics.

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.

Time Course and Risk Factors for Repeat Procedures After Ureteroscopy or Shockwave Lithotripsy

OBJECTIVE

To determine risk factors and time course for repeat procedures after ureteroscopy (URS) or shockwave lithotripsy (SWL) procedure using a large employer-based claims database.

METHODS

We identified all patients who underwent treatment for ureteral or renal stone with URS or SWL from January 1, 2007 to December 31, 2014 using the IBM MarketScan Commercial Database. Repeat stone procedure was evaluated after a 90-day grace period from the index procedure. Patients were followed until December 31, 2017. We performed multivariate analyses using Cox proportional hazards to determine independent risk factors for repeat procedure after the initial stone removal.

RESULTS

A total of 189,739 patients underwent a SWL or URS and were included in the study. The incidence of repeat procedure per 100 person years was 6.8, and 4.4 after SWL and URS, respectively. The median time to reoperation was 12.5 months for SWL and 14.6 months for URS. On multivariable analysis, SWL was associated with an increased risk of repeat procedure compared to URS. (HR = 1.63). Paralysis, neurogenic bladder and inflammatory bowel disease were also associated with an increased risk of repeat procedure (HR = 1.66, 1.40, and 1.36 respectively) CONCLUSION: In a large national cohort, patients with paralysis and neurogenic bladder had a significantly higher risk of repeat stone procedure. SWL was associated with higher risk of repeat procedure than URS. Urologists can use these data to identify and counsel patients at high risk for need for recurrent procedure.

Prospective comparison of extracorporeal shock wave lithotripsy versus flexible ureterorenoscopy in patients with non-lower pole kidney stones under the COVID-19 pandemic

Both shock wave lithotripsy (SWL) and flexible ureterorenoscopy (F-URS) are recommended as the first choice for non-lower pole kidney stones. Therefore, we conducted a prospective study to evaluate the efficacy, safety, and cost of SWL versus F-URS in patients with solitary non-lower pole kidney stones ≤ 20 mm under the COVID-19 pandemic. This prospective study was conducted in a tertiary hospital from June 2020 to April 2022. Patients who underwent lithotripsy (SWL or F-URS) for non-lower pole kidney stones were enrolled in this study. The stone-free rate (SFR), retreatment rate, complications, and cost were recorded. Propensity score-matched (PSM) analysis was performed. A total of 699 patients were finally included, of which 81.3% (568) were treated with SWL and 18.7% (131) underwent F-URS. After PSM, SWL showed equivalent SFR (87.9% vs. 91.1%, P = 0.323), retreatment rate (8.6% vs. 4.8%, P = 0.169), and adjunctive procedure (2.6% vs. 4.9%, P = 0.385) compared with F-URS. Complications were scarce and also comparable between SWL and F-URS (6.0% vs 7.7%, P > 0.05), while the incidence of ureteral perforation was higher in the F-URS group compared with the SWL group (1.5% vs 0%, P = 0.008). The hospital stay was significantly shorter (1 day vs 2 days, P < 0.001), and the cost was considerably less (1200 vs 30,083, P < 0.001) in the SWL group compared with the F-URS group. This prospective cohort demonstrated that SWL had equivalent efficacy with more safety and cost benefits than F-URS in treating patients with solitary non-lower pole kidney stones ≤ 20 mm. During the COVID-19 pandemic, SWL may have benefits in preserving hospital resources and limiting opportunity for virus transmission, compared to URS. These findings may guide clinical practice.

Comparative analysis of ureteroscopic laser lithotripsy and extracorporeal shock wave lithotripsy in the treatment of childhood proximal ureteral stones

PURPOSE

This study aims to make a comparative analysis of the superiority of ESWL and URS in proximal ureteral stones in children.

METHODS

A total of 155 patients under the age of 15 were included in the study. The patients were divided into two groups as Group 1 (n = 80, ESWL) and Group 2 (n = 75, URS) according to the type of procedure performed. The patients in both groups were evaluated in terms of age, gender, lateralization, stone size, stone volüme, stone density, and preoperative hydronephrosis. In addition, both methods used were compared in terms of success rate, time, cost, hospitalization and complications.

RESULTS

The mean age were 7.4 ± 2.1 in Group-1 and 8.1 ± 1.8 in Group-2. Demographic, clinical and laboratory data of both groups were similar. The hospitalization time, procedure time, success rate and cost were significantly higher in Group-2. The complication rate was significantly higher in Group-2 (p < 0.001). There was a significant negative correlation between ESWL success and stone volume (ρ - 0.375, p = 0.001) and stone density (ρ - 0.283, p = 0.011).

CONCLUSION

ESWL can be performed as the first line treatment of proximal ureteral stones in children due to its daily use, low cost, short procedure time and low complication rate. Increasing stone volume and density reduces the success of ESWL.

Failure of ureteral access sheath insertion in primary flexible ureteroscopy for renal stones: is there any relation with inflammation?

PURPOSE

To investigate the relationship between failure to insert a ureteral access sheath (UAS) with inflammation and other clinical parameters in patients treated with flexible ureteroscopy for renal stones.

METHODS

This study included patients who underwent flexible ureteroscopy for the treatment of renal stones in our centre between 2015 and 2020. Patients who underwent any surgical procedure on the ipsilateral ureter and had a history of spontaneous stone passage were excluded. Patients were divided into two groups based on UAS insertion success (group 1) or failure (group 2). Both groups were compared with a view to clinical characteristics, preoperative neutrophil, lymphocyte, monocyte and platelet counts and ratios of these counts, all being considered inflammatory markers. A multivariate logistic regression analysis was performed to determine the independent variables affecting UAS insertion success.

RESULTS

There were 113 (59.1%) patients in group 1, while group 2 consisted of 78 (40.9%) patients. The rates of male gender, coronary artery disease and preoperative ipsilateral hydronephrosis were significantly higher in group 2, while platelet counts and platelet-lymphocyte ratios were significantly lower. Our analysis revealed four independent predictors for UAS insertion failure: female gender (odds ratio [OR]=2.1) increased the rate of UAS insertion success, while hydronephrosis (OR=1.6), low platelet counts and PLR increased the rate of UAS insertion failure (OR=0.99, OR=0.98, respectively).

CONCLUSION

Our results suggest that male gender and ipsilateral hydronephrosis are associated with increased UAS insertion failure. Although we found a relationship between relatively low platelet levels and UAS insertion failure, we think that further studies are needed to investigate this matter.

Factors influencing extracorporeal shock wave lithotripsy efficiency for optimal patient selection

Introduction

Current literature suggests various predictors related to the stone and patient, which could influence stone fragmentation and clearance rates.

Aim

To establish clinical characteristics of stone disease for patients undergoing extracorporeal shockwave lithotripsy (ESWL) which may predict the success of the procedure.

Material and methods

One hundred and nine patients with renal stone disease diagnosed by non-contrast computed tomography (NCCT) who underwent ESWL between January 2015 and December 2019 were included in the study. Endpoints: patient being stone free (SF) or when < 4 mm fragments were detected. Age, gender, location, skin-to-stone distance, maximum stone length, stone volume, stone surface area, mean stone Hounsfield units (HU) and highest HU score were explored in uni- and multivariate regression analysis.

Results

Stone size revealed the highest prognostic power for ESWL failure, where OR for stone volume and stone surface area were 1.06 (1.03–1.10) and 1.04 (1.02–1.06), respectively (all p < 0.01) while a tendency was observed for skin-to-stone distance 1.02 (1.00–1.03). The amount of energy applied during the procedure to one cubic millimeter of stone volume (SMLI/stone volume) was predictive for treatment success (OR = 0.60, 95% CI: 0.41–0.87, p < 0.01). Stone volume (OR = 1.06, 95% CI: 1.00–1.14, p = 0.01) and stone surface area (OR = 1.03, 95% CI: 1.01–1.06, p = 0.02) remained as statistically significant prognostic factors for treatment failure.

Conclusions

Both greater stone volume and stone surface area, as well as lower power delivered per stone volume unit during the ESWL procedure, were found to be significant factors and could be useful to predict treatment failure.

Effectiveness of Flexible Ureterorenoscopy Versus Extracorporeal Shock Wave Lithotripsy for Renal Calculi of 5-15 mm: Results of a Randomized Controlled Trial

Background

Primary flexible ureterorenoscopy (URS) and extracorporeal shock wave lithotripsy (SWL) are treatment options in patients with renal calculi of 5-15 mm.

Objective

To compare effectiveness, complication rates, and pain scores between primary URS and SWL.

Design setting and participants

Between 2011 and 2016, patients with renal calculi between 5 and 15 mm were randomized to undergo either primary URS or SWL.

Outcome measurements and statistical analysis

Stone-free rate and size of residual fragments assessed by computed tomography after 3 mo, complications, and pain scores were evaluated.

Results and limitations

The study was prematurely closed after randomizing 44 patients due to poor accrual. The 3-mo stone-free rate and mean residual stone size were, respectively, 61% and 1.8 mm after URS and 48% and 2.4 mm after SWL. Early post-treatment pain scores were significantly higher after URS than after SWL on day 1 (3.3 vs 1.6, p =  0.02) and day 7 (5.2 vs 3.4, p =  0.04), but were no longer detectable after 3 wk and 3 mo, respectively. One Clavien-Dindo grade II complication was observed after URS (5%) and SWL (4%), while one (4%) grade IIIb complication was observed after SWL.

Conclusions

URS appears to be associated with higher early post-treatment discomfort, which could be associated with routine postoperative stenting. Owing to premature closure of this trial, the power was insufficient to formally compare URS and SWL; however, the present data might be informative to counsel patients about treatment outcomes and allow future meta-analyses.

Patient summary

This study was ended prematurely, but it contributes data about efficacy and side effects of different treatment options in patients with renal calculi.

Demographic and Socioeconomic Factors Associated with Urinary Stone Disease Management in a Large Urban US Population

OBJECTIVE

To determine the influence of socioeconomic parameters on urinary stone surgeries.

METHODS

A retrospective cohort study analyzed patients undergoing urolithiasis surgery in our community network hospital in North Carolina from 2005-2018.

RESULTS

Of 7731 patients, 2160 (28%), 5,174 (67%), and 397 (5%) underwent SWL, URS, and PCNL, respectively. A higher proportion of Whites underwent URS (67%) and SWL (74%) than PCNL (56%); whereas a larger percentage of Blacks underwent PCNL (24%) than URS (20%) and SWL (15%) groups (P <.001). Private insurance payers were greater in the SWL (95%) group than URS (80%) and PCNL (81%) (P <.001). The distribution of median income was significantly different amongst the 3 surgeries with higher income classes overutilizing SWL and underutilizing PCNL compared to lower income classes (P <.001). In linear regression modeling, the proportion of SWL in a postal code was positively associated with median income (R²=0.55, P <.001); URS and PCNL were negatively associated with median income (R²=0.40, P <.001 and R²=0.41, P <.001, respectively). On multivariate logistic regression modeling, Blacks were significantly more likely to undergo PCNL than Whites (aOR 1.32, 95% CI 1.01-1.74 P <.050). Private insurance payers were more likely to undergo SWL (aOR 11.0, 95% CI 7.26-16.8, P <.0001) than public insurance payers. Patients in higher median income brackets are significantly less likely to undergo PCNL than those in the <$40,000 income bracket (P <.0001).

CONCLUSION

Our study suggests that socioeconomic status impacts urolithiasis surgical management, underscoring disparity recognition importance in endourologic care and ensuring appropriate surgical care regardless of socioeconomic status.

Is health-related quality of life of patients after single-use flexible ureteroscopy superior to extracorporeal shock wave lithotripsy? A randomised prospective study

The aims of the study were to compare the change in the Wisconsin Stone Quality of Life (WISQOL) score in patients who underwent retrograde intrarenal surgery (RIRS) single-use ureteroscope or extracorporeal shock wave lithotripsy (ESWL) with a calculation of quality-adjusted life-years (QALYs). 158 patients treated with urinary stone disease were randomly divided into 80 patients in the validation and 78 patients in the intervention arm. Patients in the intervention arm were randomly divided into the RIRS or the ESWL group. Linguistic validation of the WISQOL into the Slovak language was performed using a standardised multistep process. Discriminant validity was assessed by comparing stone-forming patients to an additional 34 healthy individuals. Patients were asked to fill in the WISQOL before and in the 24th week after the intervention. The QALYs were calculated by the formula QALY = weight factor (WF) x time period after intervention. The Cronbach's α of the WISQOL was 0.94, the Pearson's coefficient for test-retest reliability was 0.91, and the discriminant validity confirmed a higher score for healthy individuals (p < 0.001). The median WISQOL score changed from 45.5 to 95.5 vs. 33.9 to 87.1 in the RIRS and ESWL groups, respectively (p < 0.001). Patients from the RIRS group had a good possibility of reaching 19.727 QALYs gained during life expectancy compared to 15.780 for the ESWL group (p < 0.001). RIRS single-use ureteroscope is significantly superior to ESWL in reaching more QALYs gained during life expectancy. The WISQOL Slovak version is valid, reliable and strictly specific for stone-forming patients.

Ckj consolidation among Q1 Urology and Nephrology journals

The Clinical Kidney Journal (ckj) impact factor from Clarivate’s Web of Science for 2019 was 3.388. This consolidates ckj among journals in the top 25% (first quartile, Q1) in the Urology and Nephrology field according to the journal impact factor. The manuscripts contributing the most to the impact factor focused on chronic kidney disease (CKD) epidemiology and evaluation, CKD complications and their management, cost-efficiency of renal replacement therapy, pathogenesis of CKD, familial kidney disease and the environment–genetics interface, onconephrology, technology, SGLT2 inhibitors and outcome prediction. We provide here an overview of the hottest and most impactful topics for 2017–19.

Treatment of non-obstructive, non-struvite urolithiasis is effective in treatment of recurrent urinary tract infections

PURPOSE

To determine if treatment of non-obstructing urolithiasis is effective in management of recurrent UTI.

MATERIALS AND METHODS

A retrospective review was performed of patients undergoing elective management of non-struvite upper tract urinary calculi with recurrent UTI from 2009 to 2016. Recurrent UTI was defined at ≥ 3 UTI in 12 months, with symptoms and documented urine culture. Preoperative CT was performed in all patients to determine stone burden. All patients had postoperative imaging and ≥ 12 months of follow-up. Pre- and postoperative variables were between patients who had recurrent UTI after treatment versus those who did not.

RESULTS

46 patients met inclusion criteria. 42 (91.3%) were female. Median age was 63.7 years (IQR 49.1, 73.4) and median total stone burden was 20 mm (IQR 14-35). Within the cohort, 20 (43.5%) underwent ureteroscopy only, 26 (56.5%) underwent PCNL ± URS, and none underwent ESWL. Median postoperative follow-up was 2.9 years (IQR 2.0, 4.3). Only five patients (10.9%) had recurrent UTI after treatment. 80% were with the preoperative pathogen. The presence of residual stone was an independent risk factor for recurrent UTI after treatment (p < 0.046). Diabetes, hypertension, immunosuppression and chronic kidney disease were not.

CONCLUSIONS

Stone removal for patients with recurrent UTIs was associated with a high rate of success (89.1%) in elimination of further recurrent UTIs. Residual fragments are independently associated with persistent recurrent UTIs and thus, complete stone removal is of paramount importance in treatment of this patient population.

Characteristics of current digital single-use flexible ureteroscopes versus their reusable counterparts: an in-vitro comparative analysis

Background

Single-use flexible ureterorenoscopes (fURSs) have been recently introduced aiming to offer solutions to the sterilization, fragility and cost issues of the reusable fURSs. In order to be a viable alternative, the single-use scopes must prove similar capabilities when compared to their reusable counterparts. The goal of our in-vitro study was to compare the current reusable and single-use digital fURSs regarding their deflection, irrigation and vision characteristics.

Methods

We compared in-vitro 4 single-use fURSs-LithoVue™ (Boston Scientific, Marlborough, Massachusetts, USA), Uscope™ (Zhuhai Pusen Medical Technology Co. Ltd., Zhuhai, Guangdong Province, China), NeoFlex™ (NeoScope Inc, San Jose, California, USA) and ShaoGang™ (YouCare Technology Co. Ltd., Wuhan, China) versus 4 reusable fURSs-FLEX-X^c (Karl Storz SE & Co KG, Tuttlingen, Germany), URF-V2 (Olympus, Shinjuku, Tokyo, Japan), COBRA vision and BOA vision (Richard Wolf GmbH, Knittlingen, Germany). Deflection and irrigation abilities were evaluated with different instruments inserted through the working channel: laser fibres (200/273/365 µm), retrieval baskets (1.5/1.9/2.2 Fr), guide wires [polytetrafluoroethylene (PTFE) 0.038 inch, nitinol 0.035 inch] and a biopsy forceps. A scoring system was designed to compare the deflection impairment. Saline at different heights (40/80 cm) was used for irrigation. The flow was measured with the tip of the fURS initially straight and then fully deflected. The vision characteristics were evaluated (field of view, depth of field, image resolution, distortion and colour representation) using specific target models.

Results

Overall, the single-use fURSs had superior in-vitro deflection abilities than the reusable fURSs, in most settings. The highest score was achieved by NeoFlex™ and the lowest by ShaoGang™. PTFE guide wire had most impact on deflection for all fURSs. The 200 µm laser fibre had the lowest impact on deflection for the single-use fURSs. The 1.5 Fr basket caused the least deflection impairment on reusable fURSs. At the end of the tests, deflection loss was noted in most of the single-use fURSs, while none of the reusable fURSs presented deflection impairment. ShaoGang™ had the highest irrigation flow. Increasing the size of the instruments occupying the working channel led to decrease of irrigation flow in all fURSs. The impact of maximal deflection on irrigation flow was very low for all fURSs. When instruments were occupying the working channel, the single-use fURSs had slightly better in-vitro irrigation flow than the reusable fURSs. The field of view was comparable for all fURSs, with LithoVue™ showing a slight advantage. Depth of field and colour reproducibility were almost similar for all fURSs. ShaoGang™ and Uscope™ had the lowest resolution. FLEX X^c had the highest image distortion while LithoVue™ had the lowest. Partial field of view impairment was not for Uscope™ and ShaoGang™.

Conclusions

In-vitro, there are differences in technical characteristics of fURSs. It appears that single-use fURSs deflect better than their reusable counterparts. Irrespective of deflection, the irrigation flow of the single-use fURSs was slightly superior to the flow of the reusable fURSs. Overall, reusable fURSs had better vision characteristics than single-use fURSs. Further in-vivo studies might be necessary to confirm these findings.

Regional Variation in Shock Wave Lithotripsy Utilization Among Medicare Patients with Nephrolithiasis

OBJECTIVE

To characterize shock wave lithotripsy (SWL) utilization and assess for regional variation in the use of this procedure across the United States.

MATERIALS AND METHODS

We examined SWL and URS utilization among Medicare Beneficiaries with a diagnosis of nephrolithiasis for the years 2006, 2009, and 2014. Adjusted utilization rates were calculated per 1000 beneficiaries accounting for age, sex, and race. Utilization rates were examined nationally and by hospital referral region (HRR).

RESULTS

A total of 511,495, 604,493, and 806,652 Medicare beneficiaries had a diagnosis of nephrolithiasis in 2006, 2009, and 2014, respectively. The adjusted rate of SWL per 1000 beneficiaries with nephrolithiasis decreased from 59.4/1000 in 2006 to 52.2/1000 and 45.5/1000 in 2009 and 2014 (13.9% decrease, P < .001). Variation was observed in SWL utilization; up to a 12-fold difference between HRRs (9.2/1000 in Winchester, VA to 105.8/1000 in Lincoln, NE). The adjusted rate of URS per 1000 beneficiaries increased by 10.2% (P < .001) between 2006 and 2014. However, the percent decrease in SWL utilization did not correlate with the percent increase in URS utilization when examined by HRR (P = .66).

CONCLUSION

Variation exists in the utilization of SWL among Medicare beneficiaries (12-fold difference). This variation is likely secondary to a series of supply, urologist, and patient-specific factors. SWL utilization decreased between 2006 and 2014, while URS increased. Stone procedure type is likely highly dependent on where patients receive their urologic care.

Stone residual fragments: A thorny problem

Urolithiasis represents a widespread and common disorder among the world population, with a predicted increase in affected patients in the coming years. Treatment of renal and ureteral stones varies widely, and achieving true stone-free status in all patients is still difficult. Moreover, imaging used to assess residual fragments following procedure impacts the diagnosed stone-free rate percentage considerably. In particular, the use of computed tomography scans has led to a better evaluation of residual fragments as well as so-called clinically insignificant residual fragments, which in a considerable number of cases are, despite their definition, causes of adverse urological events, thus creating a thorny problem for both patients and urologists. Currently, there is no gold standard or validated protocol regarding the management, clearance and prevention of residual fragments. In this article, we review the current literature regarding residual fragments, clinically insignificant residual fragments and their natural history, reporting on diagnostic methods, incidence, complications and outcome with the use of less invasive procedures, taking into consideration viable treatment and management of patients affected.

Outcomes of retrograde intrarenal surgery compared with ultra-mini percutaneous nephrolithotomy in the management of renal calculi

INTRODUCTION

To evaluate the outcomes of retrograde intrarenal surgery (RIRS) and ultra-mini percutaneous nephrolithotomy (umPCNL) in the management of renal calculi.

MATERIAL AND METHODS

Between March 2015 and January 2018, a total of 44 patients were treated with umPCNL. The outcomes of these patients were compared with 75 patients who underwent RIRS for renal calculi during the same time period.

RESULTS

Median stone size was 9 mm in the umPCNL group and 7 mm in the RIRS group. Stone-free rates after a single procedure were achieved in 85% of patients for the RIRS group and 98% for the umPCNL group. 16% of RIRS patients were left with a ureteric stent, whilst 7% of patients (n = 5) needed a second RIRS. One patient in the umPCNL group was left with a percutaneous nephrostomy; all other patients were left totally tubeless. The mean operative time was 66 minutes in the RIRS group and 55 minutes in the umPCNL group (p = 0.04). The minor complication rates for the RIRS and umPCNL groups were 17% and 15%, respectively. One patient in the RIRS group required postoperative nephrostomy insertion; there were no major complications in the umPCNL group. The median length of stay was 0 days in the RIRS group and 1 day in the umPCNL group.

CONCLUSIONS

The overall study showed that umPCNL has low complication rates and good stone-free rates, with a lower requirement for ancilliary procedures. UmPCNL is an acceptable alternative in selected patients with small- to moderate-sized renal calculi.

The new Clinical Kidney Journal, 4 years later

The February 2015 issue of ckj started a new era with renewed efforts to be useful to the training and practicing nephrologists and a new focus on Clinical and Translational Nephrology. Four years later, it has become a truly global journal with contributors and readers from all over the world. The increase in quality of the published material has resulted in a nearly exponential growth of citations. Since 2016, ckj is listed in the new Emerging Sources Citation Index (ESCI) database from Clarivate Analytics and from January 2019 it will be listed in the full Science Citation Index. ckj will therefore receive its first official impact factor based upon 2018 citation to 2016 and 2017 articles. While no official impact factor was awarded for 2017, the estimated impact factors calculated from data available in Clarivate's Web of Science database rose to 2.987 in 2017, which would correspond to an estimated journal impact factor percentile of 72.4% in the Urology and Nephrology field.

Prevalence of hypertension and diabetes after exposure to extracorporeal shock-wave lithotripsy in patients with renal calculi: a retrospective non-randomized data analysis

PURPOSE

To evaluate the association of shock-wave lithotripsy (SWL) for kidney stones and hypertension or diabetes.

METHODS

Patients with urolithiasis treated by SWL were retrospectively identified. To assess whether shock-wave application to the kidney is associated with long-term adverse effects, patients after SWL for kidney stones were selected as the main group of interest. Patients treated with shock waves for distal ureter stones only were chosen as a comparison group. A questionnaire was sent to all patients to assess the prevalence of hypertension and diabetes. The Swiss Health Survey (SHS) dataset was used as an additional comparison group.

RESULTS

After a median follow-up of 13.7 years, the odds ratio (OR) to report hypertension [OR 1.30 (95% CI 1.10-1.95)] or diabetes [OR 1.54 (95% CI 1.21-1.97)] was significantly higher in patients treated with SWL compared to the SHS dataset. In comparison with the kidney group, participants in the SHS had a significantly lower OR to report hypertension at follow-up [OR 0.79 (95% CI 0.65-0.95)], while the OR to report hypertension [1.16 (95% CI 0.79-1.70)] was not significantly different in the distal ureter group. For diabetes, a significantly lower [OR 0.60 (95% CI 0.46-0.78)] in the SHS group and a non-significantly lower [OR 0.68 (95% CI 0.38-1.22)] in the ureter group was noted compared to the kidney group.

CONCLUSION

Compared to the SHS data set SWL was in general associated with hypertension and diabetes. However, no clear difference between patients after SWL to the kidney compared to SWL to the distal ureter was seen and thus the data do not support a causal relationship.