A Population Based Study of the Changing Demographics of Patients Undergoing Definitive Treatment for Kidney Stone Disease

Antiurolithiatic effects of Cassia fistula Lin. fruit extracts on ethylene glycol-induced nephrolithiasis in rats

Urinary stones are a growing disease that results from pathological biomineralization. Cassia fistula Lin. is traditionally used to treat urinary stones. However, no scientific evidence is available to prove its antilithiatic effect. This study evaluates the antilithiatic potential of aqueous and ethanolic extract of Cassia fistula Lin. fruit (Cff) against calcium oxalate kidney stones. Forty-two male Wistar rats were divided into seven groups (n = 6/group): Group I (control), Group II (rats treated with ethylene glycol and ammonium chloride developed nephrolithiasis after 28 days), Group III (lithiatic rats receiving distilled water for 30 days), Group IV and V (lithiatic rats receiving aqueous extract of Cff at doses of 1 and 100 mg/kg body weight for 30 days, respectively) and Group VI and VII (lithiatic rats receiving ethanolic extract of Cff at doses of 1 and 100 mg/kg body weight for 30 days, respectively). Some parameters of urine and serum, and also renal oxidative stress and histopathology were used to determine the antilithiatic effect of aqueous and ethanolic extract of Cff. Therefore, the types of extracts of Cff improved abnormal levels of urine, serum, and renal oxidative stress and histopathology parameters. This antilithiatic effect of aqueous and ethanolic extracts of Cff, can be attributed to the anti-crystallization and antioxidant properties of the extracts and the ability to improve urine and serum biochemistry. RESEARCH HIGHLIGHTS: Ethylene glycol and ammonium chloride-induced urolithiasis, aggregation of calcium oxalate deposits, increase of some urinary and serum parameters, relative kidney weight, kidney size and MDA activity, decrease of some urinary parameters, relative body weight and SOD activity. Aqueous and ethanolic extracts of Cassia fistula Lin. lead to the treatment of urolithic rats by decreasing levels of urinary oxalate, phosphate, urea, serum urea, uric acid, creatinine, calcium, phosphate, MDA, kidney weight and kidney size, increasing levels of urinary calcium, creatinine, magnesium, citrate, body weight and SOD activity in the kidney, eliminating CaOx deposition (esp. ethanolic extract).

Semirigid ureteroscopy and tamsulosin therapy as dilatation methods before flexible ureteroscopy: evaluation and benefits

OBJECTIVE

To evaluate the effect of semirigid ureteroscopy and tamsulosin therapy as dilatation methods before flexible ureteroscopy advancement to the renal collecting system.

PATIENTS AND METHODS

This prospective study included patients with renal stones less than 2 cm who underwent retrograde flexible ureteroscopy and laser lithotripsy. The patients were randomized into two groups: group A patients were given a placebo for 1 week before flexible ureteroscopy, and group B patients were administered 0.4 mg of tamsulosin once daily for 1 week before surgery and underwent active dilatation using semirigid ureteroscopy before flexible ureteroscopy. The ability of the flexible ureteroscope to reach the collecting system in both groups during the same operative session was assessed. Operative outcomes and complications were collected and analyzed in both groups.

RESULTS

A total of 170 patients were included in our study, with each group comprising 85 patients. In group B, the flexible ureteroscope successfully accessed the kidney in 61 patients, while in group A, the flexible ureteroscope was successful only in 28 cases (71.4% versus 32.9%). In group A, 33 (38.8%) patients had lower urinary tract symptoms compared to 17 (20.2%) patients in group B (P = 0.013).

CONCLUSION

Using tamsulosin therapy and semirigid ureteroscopy as dilatation methods before flexible ureteroscopy increased the success of primary flexible ureteroscopy advancement to renal collecting system.

Flexible Ureteroscopy: Global User Experience Using Disposable Devices

INTRODUCTION

Renal stone treatment through flexible ureteroscopy is widely established and successful. Ureteroscopes can broadly be classified into reusable and single-use disposable devices, each with their own advantages. Disposable scopes are cheaper to buy, maintain, and dispose of but may have a greater environmental impact and long-term cost. To establish the collective views of urologists, we conducted a multicentre, global study to demonstrate users' experience with single-use flexible ureteroscopes.  Methods: An online nine-question survey was distributed to urologists globally through email and social media platforms. Questions focused on user grade, experience, location, general opinion, advantages, disadvantages, and estimated cost of a single-use flexible ureteroscope. All responses were collated over a three-day period and analysed using descriptive statistics.

RESULTS

A total of 69 responses were received; the majority of responses were from the UK (75%), and most were consultants (64%). Two-thirds of those surveyed had used a single-use scope on a patient, and 95% of them stated they enjoyed using it, citing excellent vision and reduced need for maintenance. The majority (52%) stated that widespread adoption of disposable scopes was limited due to their prohibitive expense, with an average, sterling-converted responder-estimated cost of £991 (£100-£6000) per reusable scope.

CONCLUSION

Most urologists enjoyed using disposable scopes, finding them comparable or better than reusable devices. However, the initial cost can be prohibitive in certain centres. The potential environmental impact is a further concern as this remains largely unknown for now. In the meantime, it is likely that stone units will continue to use a combination of single-use and reusable scopes, considering their individual needs and budgets as well as local availability and price.

Real-world Practice Stone-free Rates After Ureteroscopy: Variation and Outcomes in a Surgical Collaborative

BACKGROUND

Studies assessing the stone-free rate (SFR) after ureteroscopy are limited to expert centers with varied definitions of stone free. Real-world data including community practices related to surgeon characteristics and outcomes are lacking.

OBJECTIVE

To evaluate the SFR for ureteroscopy and its predictors across diverse surgeons in Michigan.

DESIGN, SETTING, AND PARTICIPANTS

We assessed the Michigan Urological Surgery Improvement Collaborative (MUSIC) clinical registry for patients with renal or ureteral stones treated with ureteroscopy between 2016 and 2021 who had postoperative imaging.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Stone free was defined as no fragments on imaging reports within 60 d entered by independent data abstractors. Factors associated with being stone free were examined using logistic regression, including annual surgeon volume. We then assessed variation in surgeon-level SFRs adjusted for risk factors.

RESULTS AND LIMITATIONS

We identified 6487 ureteroscopies from 164 surgeons who treated 2091 (32.2%) renal and 4396 (67.8%) ureteral stones. The overall SFRs were 49.6% (renal) and 72.7% (ureteral). Increasing stone size, lower pole, proximal ureteral location, and multiplicity were associated with not being stone free. Female gender, positive urine culture, use of ureteral access sheath, and postoperative stenting were associated with residual fragments when treating ureteral stones. Adjusted surgeon-level SFRs varied for renal (26.1-72.4%; p < 0.001) and ureteral stones (52.2-90.2%; p < 0.001). Surgeon volume was not a predictor of being stone free for renal stones. Limitations include the lack of imaging in all patients and use of different imaging modalities.

CONCLUSIONS

The real-world complete SFR after ureteroscopy is suboptimal with substantial surgeon-level variation. Interventions focused on surgical technique refinement are needed to improve outcomes for patients undergoing ureteroscopy and stone intervention.

PATIENT SUMMARY

Results from a diverse group of community practicing and academic center urologists show that for a large number of patients, it is not possible to be completely stone free after ureteroscopy. There is substantial variation in surgeon outcomes. Quality improvement efforts are needed to address this.

Single-use flexible ureteroscopes: Comparative in vitro analysis of four scopes

Objective

Single-use flexible ureteroscopes (fURSs) have recently been introduced by different companies. Goal of this in-vitro study was to compare four fURSs.

Methods

We performed in vitro analysis of Uscope 7.5 Fr and Uscope 9.5 Fr (Pusen Ltd., Zhuhai, China), LithoVue 9.5 Fr (LithoVue™, Boston Scientific, MA, USA), and Indoscope 9.5 Fr (Bioradmedisys™, Pune, India). Optical characteristics (image resolution, color representation, and luminosity) were compared at various distances of 10 mm, 20 mm, and 50 mm. Deflection and irrigation were evaluated with and without accessories.

Results

Color perception was comparable for all scopes at 10 mm (p<0.05), while Lithovue 9.5 Fr was comparable with Indoscope 9.5 Fr at the distances of 20 mm and 50 mm. Both scopes were statistically better than both Uscopes at the distances of 20 mm and 50 mm. Image resolution powers were comparable amongst all fURSs at the distances of 10 mm and 20 mm (3.56 line pairs per millimeter [lp/mm]). However, Indoscope (3.56 lp/mm) was superior to LithoVue and Uscope scopes (3.17 lp/mm) at the distance of 50 mm. Luminosity at the distance of 10 mm was comparable for LithoVue and Uscope 9.5 Fr. However, at the distances of 20 mm and 50 mm, LithoVue had the highest luminosity while Uscope 7.5 Fr had the lowest one. Indoscope had lower luminosity than other 9.5 Fr scopes at all distances. With empty working channel and 200 μm laser fiber, Indoscope had the maximum deflection (285°). With basket, Uscope 7.5 Fr had the maximum loss of deflection (30°) while Indoscope had no deflection loss. With empty working channel, all scopes had comparable irrigation flow rates in both deflected and undeflected state. Similarly, with 200 μm laser or basket, irrigation flow rates were comparable in all scopes.

Conclusion

Color representation was equivalent for Indoscope and LithoVue, while being better than Uscope 7.5 Fr and Uscope 9.5 Fr. Image resolution was comparable in all scopes at the distances of 10 mm and 20 mm. Beyond the distance of 10 mm, luminosity of LithoVue was the highest and that of Uscope 7.5 Fr was the lowest. Deflection loss was the minimum with Indoscope and the maximum with 7.5 Fr Uscope. Under all scenarios, irrigation flow rates were comparable in all scopes.

Microdamage analysis of single-use flexible ureteroscope immediately after lithotripsy use

This prospective ex vivo study investigated microdamage to single-use flexible ureteroscopes (fURS) after ureteroscopy and endoscopic combined intrarenal surgery (ECIRS). The performance of 30 WiScope devices (OTU Medical, San Jose, CA, USA) was examined immediately after use, dividing them into three equal groups: ureteroscopy and ECIRS in the prone and supine positions. The overall scope of microdamage assessment included the scope deflection, bending radius, resolution, and water flow rate. Additionally, we analyzed the association between scope status and surgical parameters. The deflection, bending radius, and resolution remained similarly above the thresholds in all groups. However, the water flow rate was below the threshold in seven scopes (70%) in the ureteroscopy group and none in the ECIRS groups (P = 0.001). Univariate and multivariable logistic regression analyses demonstrated that basket wire catheter use was associated with an increased risk for overall scope microdamage (odds ratio [OR], 22.70; P = 0.006 and OR, 22.40; P = 0.019, respectively). Stone size, total laser energy, and surgical position were not associated with a risk for scope microdamage. In conclusion, ureteroscopy was more closely associated with scope damage than ECIRS, and basket wire catheter use seemed to inflict more damage to the fURS.

WiScope® single use digital flexible ureteroscope versus reusable flexible ureteroscope for management of renal stones: a prospective randomized study

OBJECTIVES

To compare the clinical performance and surgical outcomes of the new digital single use flexible ureteroscope (WiScope^®) with a reusable digital flexible ureteroscope.

PATIENT AND METHODS

Our prospective study includes patients with renal stones less than 2 cm who underwent retrograde flexible ureteroscopy and laser lithotripsy. Patients were randomized into two groups: group A included patients who underwent laser lithotripsy using WiScope^® Single use digital flexible ureteroscope and group B included patients who underwent laser lithotripsy using reusable flexible ureteroscope. Image quality, deflection, ease of insertion, maneuverability, and overall performance were assessed using either a visual analog or Likert scale. Operative outcomes and complications were collected and analyzed in both groups.

RESULTS

A total of 242 patients were included in our study. There were 121 patients in the WiScope^® group and 121 patients in reusable ureteroscope group. The WiScope^® had higher maneuverability (9.3 ± 0.7 vs. 7.2 ± 0.8, P < 0.001) and less limb fatigue but had lower image quality when compared to reusable digital flexible ureteroscope (7.6 ± 0.9 vs. 9.2 ± 0.6, P < 0.001). There were no differences in operative time, complication rates and rates of relook ureteroscopy.

CONCLUSIONS

The WiScope^® single use flexible ureteroscope has comparable outcomes to the reusable flexible ureteroscope with regard to maneuverability, limb fatigue, and deflection. However, it has a lower image quality.

Development of a novel predictive model for a successful stone removal after flexible ureteroscopic lithotripsy based on ipsilateral renal function: a single-centre, retrospective cohort study in China

OBJECTIVES

The aims of this study were to investigate the effect of preoperative ipsilateral renal function on the success of kidney stone removal with flexible ureteroscopic lithotripsy and to develop a predictive model based on the results.

DESIGN

Retrospective cohort study.

SETTING

Data from the 2001-2012 period were collected from the electronic records of West China Hospital, Sichuan University.

PARTICIPANTS

576 patients who underwent flexible ureteroscopic lithotripsy were included in the study.

PRIMARY OUTCOME

Stone-free rate (SFR) after the procedures.

RESULTS

In patients with suspected impaired kidney function, the overall SFR was 70.1%. Stone volume (OR 1.46; 95% CI 1.18 to 1.80), lower calyx stones (OR 1.80; 95% CI 1.22 to 2.65), age (OR 1.02; 95% CI 1.00 to 1.04), body mass index (OR 1.10; 95% CI 1.04 to 1.17) and estimated glomerular filtration rate of the affected kidney (OR 0.95; 95% CI 0.94 to 0.97) were identified as independent predictors of SFR. Lasso regression selected the same five predictors as those identified by univariate and multivariate logistic regression analyses, thus verifying our model. The mean area under the curve, based on 1000 iterations and 10-fold validation, was 0.715 (95% CI 0.714 to 0.716). The Hodges-Lehmann test and calibration curve analysis revealed no significant mismatch between the prediction model and the retrospective cohort.

CONCLUSION

Ipsilateral renal function may be a novel independent risk factor for kidney stone removal with flexible ureteroscopic lithotripsy. A novel nomogram for predicting SFR that uses stone volume, lower calyx stones, age, body mass index and estimated glomerular filtration rate was developed, but remains to be externally validated.

Characteristics and Types of Urolithiasis in the Eastern Region of Saudi Arabia: A Single-Center Retrospective Study

Introduction

Urolithiasis is one of the most common conditions encountered in clinical practice with the prevalence increasing globally in the last few decades. Urolithiasis has been found to be more common in areas with a hot climate, such as Saudi Arabia. The aim of this study was to determine the characteristics and the types of urolithiasis most frequently found in the Eastern Region of Saudi Arabia.

Methods

This was a single-center retrospective cohort study based on data extracted from an electronic hospital information system (BESTCare) of all patients diagnosed with urolithiasis at King Abdulaziz Hospital, a tertiary care center in Saudi Arabia's Eastern Region. From January 2013 to December 2016, all adult patients aged 18 and up who presented with urinary calculi (renal and ureter) were included in the study.

Results

A total of 235 patients were reviewed, with a mean age of 48.52 years. Renal calculi were more prevalent in males (74.5%). Calcium oxalate was the predominant type (76%), followed by uric acid calculi (18%) and cystine calculi (4.8%). A small proportion (1.2%) was calcium phosphate calculi. The most frequently associated comorbidity was hypertension (17.9%). The majority (78.5%) had a stone removal through a ureteroscopy and 8.2% by percutaneous nephrolithotomy (PCNL). The mean stone size was 12.2 ± 9.91 mm, with a mean stone Hounsfield unit (HU) of 789.9. The mean urinary PH at stone incident was 6.77, and the mean creatinine level was 92.4mmol.

Conclusion

This study showed that males were more affected by urolithiasis, compared to females in the Eastern Region. Furthermore, calcium oxalate was the predominant type. These findings are consistent with the literature and they highlighted the necessity for further studies in this area, to provide insight into the pathophysiology and incidence of renal calculi for improving patient care.

The Trends of Urolithiasis Therapeutic Interventions over the Last 20 Years: A Bibliographic Study

Introduction: The clinical and economic burden of kidney stones is a challenge for the healthcare system. There is a limited bibliometric project exploring the literature trends on 'urolithiasis' and its related management. Methods: A systematic review was conducted to discover the related abstracts regarding each specific issue, investigated year by year from May 2000 to May 2020 (20 years). To make an effective comparison, the statistics resulting from every single study were allocated to two 10-year periods: period 1 (2000 to 2010) and period 2 (2010 to 2020). In this study, we included all English language articles, all non-English articles with English abstracts, and studies in which interventions were used for stone removal, including laser technology. Also, we excluded the studies without a published abstract, an intervention or a laser, animal and in vitro studies, and case reports. Results: These articles are about ureteroscopy (URS) (n=10360, 33.45%), percutaneous nephrolithotomy (PCN) (n =10790, 34.84%) and extra-corporeal shockwave lithotripsy (ESWL) (n=9846, 31.76%). When evaluating the two time periods, there were 9912 studies available in period one, which increased by ×2.12 times (112.71% rise) to 21084 studies in period two (P = 0.001). The increase was 133%, 103.51%, and 70.4% for URS, PCN, and SWL respectively. A total of 855 studies on Laser application via URS were published on PubMed over a 20-year period. There was an increasing trend toward using laser application via URS over the study period. Also, there were 230 articles published in period one, which increased by nearly 2.71 times (rise of 171.73%) to 625 papers in period two (P < 0.001). There was an increasing trend toward using laser application via PCN; 126 papers were published in period one, which increased by nearly 3.05 times (rise of 205.5%) to 385 papers in period two (P = 0.002). Conclusion: The minimal invasive interventions for stone removal, including URS and PCN, increased dramatically in the last decade, and the use of lasers in stone treatment increased significantly in the last decade.

Initial experience with slimmest single-use flexible ureteroscope Uscope PU3033A (PUSEN™) in retrograde intrarenal surgery and its comparison with Uscope PU3022a: a single-center prospective study

PURPOSE

Single-use disposable digital flexible ureterorenoscope has become an attractive option to reusable scope with many advantages. Currently available single-use digital fURS have outer shaft diameter above 9 Fr which requires large access sheath insertion and sometimes double J stent placement. Recently, 7.5 Fr single-use digital fURS is introduced in market by Pusen. Objective of this study is to compare two Pusen single-use scopes in the clinical setting: 7.5 Fr Uscope PU3033A and 9.5 Fr Uscope PU3022A.

METHODS

30 patients, having renal stones < 2 cm, planned for RIRS were prospectively randomized to two groups: group 1 had 15 patients in which 7.5 Fr Uscope PU3033A and group 2 had 15 patients in which 9.5 Fr Uscope PU3022A was used. The various pre-operative, intra-operative, and post-operative parameters at 1 month along with complications were evaluated for both the scopes by a single surgical team.

RESULTS

Pre-operative parameters including stone characteristics were comparable in both the groups. Three patients in group 2 needed ureteric dilatation prior to 11/13 access sheath insertion, while 10/12 Fr access sheath was placed in all patients in group 1 without manipulation (p = 0.06). Intra-operative vision was comparable in both scopes with an empty working channel and with laser. Hazy vision while lasing in two and one patient in group 1 and group 2, respectively (p = 0.54). In group 1, one had fever and UTI, while in group 2, one had fever post-operatively.

CONCLUSION

7.5 Fr Uscope PU3033A could be introduced with smaller access sheath. The vision, deflection, maneuverability is comparable to 9.5 Fr Uscope PU3022a.

Benign Prostatic Hyperplasia and Kidney Stone Disease Thermobalancing Therapy with Dr Allen’s Device: Key to Successful Ageing Without Medications, Surgery, and Risky Exposure to Coronavirus Infection

Background: The choice of treatment for benign prostatic hyperplasia (BPH) and kidney stone disease (KSD) impacts the attainment of successful ageing and the level of patient care required in the long-term. Medications and surgeries typically used for these conditions have serious side effects and can interfere with healthy aging. Objectives: This study assesses the impact of Dr Allen’s Therapeutic devices (DATD) and thermobalancing therapy® (TT) on the ageing process of people with BPH and KSD. Methods: This study evaluated the outcomes of a clinical trial investigating the dynamics of symptoms and parameters in 124 male patients with BPH who used DATD as a monotherapy for six months at home and compared the results with a control group comprising 124 BPH patients who did not receive treatment with DATD. Furthermore, five case studies were randomly selected for assessment from 10-year empirical observations of patients with KSD treated with DATD. Results: DATD with TT reduced prostate volume (PV) from 45 mL to 31 mL (P < 0.001) and reduced urinary symptoms score from 14.2 to 4.9 (P < 0.001). It also improved quality of life (QoL) as measured by the reduction in the International Prostate Symptom score (I-PSS) from 3.9 to 1.3 (P < 0.001), while the control group showed no positive changes. DATD with TT dissolved kidney stones without renal colic in all patients. No side effects were observed. Conclusions: Using DATD and TT to treat BPH and KSD demonstrated high efficacy, safety, and easy disease management at home. In contrast, medications and surgeries for BPH and KSD often lead to sexual dysfunction, depression, hypertension, chronic kidney failure, and other morbidities, requiring an increased care level in the long-term. Thus, DATD and TT generate high treatment efficacy with lower exposure to coronavirus, reduce long-term care needs, and are vital to attaining successful ageing and longevity.

Risk Factors for a Complicated Postoperative Course in Flexible Ureteroscopy

INTRODUCTION

The goal was to determine risk factors for Clavien-Dindo (CD) grade ≥2 complications, with special focus on early postoperative systemic inflammatory response syndrome (SIRS), for flexible ureteroscopy (fURS).

MATERIALS AND METHODS

A retrospective monocentric statistical analysis relating to 32 factors was performed with the χ2 test, Mann-Whitney U tests, and multivariate logistic regression.

RESULTS

In total, 416 consecutive fURS performed between September 2013 and June 2017 were analyzed; 283 (68.03%) of these were for stone surgery and 133 (31.97%) for diagnostic purposes. In 43 cases (10.34%), CD ≥2 occurred; 31 cases (72.09%) of these were SIRS. On multivariate logistic regression, positive preoperative urine culture and steep pyelographic and CT-based infundibulopelvic angle (IPA) have been confirmed as independent risk factors for both CD ≥2 and SIRS. Greater maximal median stone diameter and female gender were significantly associated only with a higher CD ≥2 prevalence, but not with SIRS. The influence of ureteral access sheath (UAS) on CD ≥ 2 or SIRS occurrence could not be confirmed on multivariate analysis. Perioperative antibiotic prophylaxis for patients with negative urine culture showed no difference regarding SIRS prevalence.

CONCLUSION

Steep CT-based IPA can be considered as a new radiologic predictor of complicated postoperative course and SIRS. The role of UAS as well as indications for perioperative antibiotic prophylaxis should be determined in prospective studies.

Evaluation of a new disposable flexible ureterorenoscope and comparison to an established disposable flexible ureterorenoscope: a prospective, observational study

PURPOSE

To objectively and subjectively assess the performance and surgical outcomes of the new Innovex EU-scope™ single-use digital flexible ureteroscope (fURS).

METHODS

A prospective cohort study was carried out (August 2019 to May 2020). The new single-use fURS (Innovex Medical Devices Co. Shanghai, China) was analysed with regard to visibility, manoeuvrability, laser interference and overall performance using a validated Likert scale. Outcomes are compared to the LithoVue™ (Boston Scientific, Marlborough, MA).

RESULTS

One hundred patients were included in this study. 50 cases underwent retrograde fURS using the Innovex EU-scope™ and 50 with the LithoVue™. There were no differences in the patient demographics data, or operative data between the two groups. The Innovex EU-scope™ scored higher visibility scores compared to the LithoVue™, median 4, interquartile range (IQR) (4-4), vs. 3.5, IQR (3-5), p = 0.5086. Both scopes had similar manoeuvrability scores. The Innovex EU-scope™ scored significantly lower with regard to comfort compared to the LithoVue, median 4 IQR (3-4) vs. 4.5 IQR (4-5), p = 0.0445. Whereas, laser interference, affected the Innovex much less than the LithoVue™. Both scopes scored well for overall performance. The median overall performance score for the Innovex was 4 IQR (4-4) vs. 4 IQR (4-5).

CONCLUSIONS

This Innovex EU-scope™ has good objective and subjective visibility and manoeuvrability profiles. This single-use flexible ureteroscope may achieve similar clinical outcomes to an established single use instrument.

The first epidemiology study of urolithiasis in New Brunswick

INTRODUCTION

Understanding the composition of a kidney stone is crucial in leading to proper treatment and preventing reoccurring urolithiasis. This study aimed to investigate the prevalence of urolithiasis in the province of New Brunswick (NB), Canada.

METHODS

A total of 3828 kidney stone analysis reports from October 1, 2016 to September 30, 2019, were reviewed from laboratory information systems. Among them, 3311 were identified as new cases. Stone compositions were analyzed by the Fourier transform infrared spectrometry. Incident rates were compared using Chi-squared analysis of different age, sex, and regional health authority (RHA) zones.

RESULTS

The prevalence of urolithiasis in NB was 147.8 per 100 000 person-years. Males had a significantly higher (X²=254, p<0.001) incident rate of 189 (95% confidence interval [CI] 182-198) than females (107 [95% CI 102-114]) per 100 000 person-years. Zone 1 had significantly higher (245 per 100 000 person-years, p<0.001) prevalence compared to other RHA zones. Age group over 65 years had the highest incidence rate of 253 per 100 00 person-years of all groups. The predominant kidney stone types in NB were calcium oxalate monohydrate (60.68%) and calcium oxalate dihydrate (11.58%). Those patients aged 0-18 years had a high percentage of struvite (4.32%) vs. the provincial average (2.19%) (p<0.001).

CONCLUSIONS

The prevalence of NB's urolithiasis is slightly higher than that of Ontario. Since both zones 1.1 and 1.2 have significantly high prevalence and are situated in the Moncton area (combined zone 1), it may suggest that geographical factors play a role in the prevalence of urolithiasis in NB.

Complications in Patients With Autosomal Dominant Polycystic Kidney Disease Undergoing Ureteroscopy: A Cohort Study

BACKGROUND

Ureteroscopy is a minimally invasive treatment option for upper tract stones. The distorted kidney anatomy in patients with autosomal dominant polycystic kidney disease (ADPKD) may place them at higher risk for ureteroscopic complications.

OBJECTIVE

To compare the 30-day risk of ureteroscopic complications between patients with and without ADPKD.

DESIGN

Retrospective cohort study.

SETTING

Ontario, Canada.

PATIENTS

Seventy three patients with ADPKD and 81 445 patients without ADPKD who underwent ureteroscopy for upper urinary tract stones between April 1, 2002, and March 1, 2018.

MEASUREMENTS

A 30-day risk of (1) hospital presentation with ureteroscopic complications (which was a composite outcome of either emergency department visit or hospital admission with acute kidney injury, urinary tract infection, or sepsis); (2) all-cause hospital presentation; (3) all-cause hospital admission; and (4) all-cause emergency department visit.

METHODS

We regressed outcomes on demographic variables, health care use in the prior 1-year, various procedures and comorbidities related to the outcome in the prior 5 years, and prescribed medications filled in the past 120 days using modified Poisson regression to compare the risk ratio (RR) of each outcome between patients with and without ADPKD.

RESULTS

The median (interquartile, IQR) age was 44 (38-60 years) in the ADPKD group and 53 (42-64) in the control group. About 40% were women in both groups. The risk of ureteroscopic complications was not significantly different in patients with versus without ADPKD (8.2% vs 4.3%; adjusted RR = 1.5, 95% confidence interval [CI] = 0.7-3.2). Patients with versus without ADPKD were more likely to present to hospital after their procedure (35.6% vs. 20.0%; adjusted RR = 1.6, 95% CI = 1.2-2.2), which included a statistically significant increase in the risk of presenting to the emergency department (32.9% vs. 19.0%; adjusted RR = 1.6, 95% CI = 1.1-2.2) but not hospital admissions (10.9% vs. 5.0%; adjusted RR = 1.8, 95% CI = 0.9-3.4).

LIMITATIONS

The low numbers of events led to imprecision around the estimates.

CONCLUSION

Patients with ADPKD have a higher risk of return to the hospital within 30 days of ureteroscopy for stone disease.

TRIAL REGISTRATION

We did not register this study.

The Impact of Endourological Experience on Flexible Ureteroscopy Outcomes and Performance at Different Levels of Expertise: Retrospective Multifactorial Analysis

INTRODUCTION

The aim of this study was to analyze the influence of residents' participation in flexible ureteroscopy (fURS) on intra- and postoperative outcomes.

MATERIALS AND METHODS

Intra- and postoperative parameters were compared in a retrospective monocentric setting between 3 groups: "resident group" (47 cases) for surgeries performed by experienced residents alone, "consultant group" (245 cases) for surgeries performed by consultants alone, "resident plus consultant group" (124 cases) for training surgeries between September 2013 and June 2017.

RESULTS

Patients operated by residents alone had a significantly smaller median kidney stone diameter (5.0 vs. 7.0 mm for "consultant group" and 6.0 mm for "resident plus consultant group," p = 0.011), shorter operating time (median 47.0 vs. 63.0 and 77.0 min, p < 0.001) and fluoroscopy time (median 39.0 vs. 69.5 and 89.0 s, p < 0.001), as well as shorter postoperative hospital stay (p = 0.013). The laser application rate was the smallest in the "resident group" (10.64 vs. 31.43 and 29.84%, p = 0.009). Univariate analysis revealed no relevant differences regarding flexible ureteroscope defect rate, postoperative stone-free rate, or ≥2 Clavien-Dindo classification complications between the groups (p > 0.05).

CONCLUSION

A proper case selection of less complicated cases, especially without laser application, could balance the experience deficit of the residents. fURS can be incorporated as a part of residents' training without an impact on fURS device defect rate or clinical outcomes.

Predictive Factors of Ureterorenoscopy Outcomes in Proximal Ureteral Stones: A Multicenter Study of Aegean Study Group of the Society of Urological Surgery

INTRODUCTION

We aimed to evaluate the predictive factors in a holistic manner for ureterorenoscopy (URS) outcomes in proximal ureteral stones by a multicenter study.

MATERIALS AND METHODS

The data of patients who underwent URS for proximal ureteral stones between the years 2015 and 2018 in eight centers were recorded retrospectively. Patients were divided into two groups according to URS success: Group 1 consisted of patients with successful URS, and Group 2 consisted of patients with unsuccessful URS. The two groups were compared in terms of risk factors, stone, and clinical characteristics of patients.

RESULTS

A total of 638 patients were included in the study. Group 1 consisted of 527 (82.6%) patients, and Group 2 consisted of 111 (17.4%) patients. In multivariate logistic analysis, the key risk factors for URS success was found to be age (OR = 0.980, 95% [CI] = 0.963-0.996, p = 0.018), stone area (OR = 0.993, 95% [CI] = 0.989-0.997, p = 0.002), and operation time (OR = 0.981, 95% [CI] = 0.968-0.994, p = 0.005).

CONCLUSIONS

To make the treatment decision of proximal ureteral stones, it is necessary to examine several parameters including available equipment, stone, and patient characteristics. Physicians should keep these risk factors in mind in the decision of treatment options.

Association of sirtuin 1 gene polymorphisms with nephrolithiasis in Eastern chinese population

Sirtuin 1 (SIRT1), an NAD⁺-dependent deacylase, has been identified to be associated with renal tubular inflammatory conditions and metabolic disorders, which are risk factors of nephrolithiasis. To further confirm the role of the SIRT1 in kidney stone formation, the expression of SIRT1 was analyzed based on a mouse model and the genetic polymorphisms of SIRT1 gene was compared between patients with kidney stones and controls. The calcium oxalate (CaOx) crystal-induced renal injury model was established to analyzed the expression of SIRT1 in the kidney tissue of both wild-type and ApoE(−/−) mice. And a total of 430 Eastern Chinese subjects (215 patients with nephrolithiasis and 215 age- and gender-matched controls) were recruited for the present study to investigate the associations between 6 common single nucleotide polymorphisms (SNPs) (i.e., rs10509291, rs3740051, rs932658, rs33957861, rs3818292 and rs1467568) in the SIRT1 gene and the incidence of kidney stones. Pairwise linkage disequilibrium and the haplotypes of the 6 SNPs were also analyzed. The genotypes of SIRT1 gene polymorphisms were analyzed by a Snapshot assay. Reduced expression of SIRT1 was observed in the kidney of the mice in the crystal group, revealing the potential role of SIRT1 in the nephrolithiasis. However, we did not find a significant association between the 6 SNPs of the SIRT1 gene and kidney stone formation in the Eastern Chinese population.

Total Surface Area Influences Stone Free Outcomes in Shock Wave Lithotripsy for Distal Ureteral Calculi

Introduction: Current American Urological Association guidelines recommend ureteroscopy (URS) as primary management of distal ureteral stones and shock wave lithotripsy (SWL) as a secondary option. Utilization of SWL in the management of nephrolithiasis in North America has decreased. We hypothesized that SWL continues to be an effective option in the management of distal ureteral calculi and studied data from our center in patients who received SWL for distal ureteral stones. Methods: A retrospective review was performed of 104 patients treated initially with SWL for distal ureteral calculi between 2011 and 2018 at this institution. The success rate of SWL was assessed through radiologic imaging and if subsequent procedures were required to render patients stone free. Results: Operative note and chart review identified 104 patients who presented with distal ureteral stones and were treated with SWL as the initial form of management. Average patient age was 52.2 ± 15.3 years, average BMI was 27.4 ± 5.7, and average total axial stone surface area was 25.96 ± 14.32 mm². Of these patients, 78.8% (n = 82) were stone free following one SWL and required no subsequent procedures. Of these patients, 87.5% (n = 91) were stone free following a second SWL, and 87.5% (n = 91) were stone free following a secondary URS. After the initial SWL, residual stones were identified in 21.2% of patients (n = 22). Four patients, 3.8%, required a salvage URS following a failed second SWL to achieve stone-free status. Conclusion: One SWL procedure offers a stone-free rate (SFR) of 78.8% and after two SWLs an 87.5% SFR. Only 12.5% of patients undergoing SWL at our center required URS to achieve a stone-free status. SWL is an effective modality in the treatment of distal ureteral stones.

Baseline chronic kidney disease does not predict long-term renal functional decline after percutaneous nephrolithotomy

To compare renal functional outcomes in patients with and without chronic kidney disease (CKD) to identify predictors of change in renal function after percutaneous nephrolithotomy (PCNL). We reviewed patients who underwent PCNL by a single surgeon over 3.5 years. Patients' pre- and post-operative Glomerular Filtration Rate (GFR) was calculated. Baseline GFR < 60 ml/min/1.73 m² (stage ≥ 3 CKD) defined our CKD cohort. Patients' baseline renal function, comorbidities, stone parameters, and intra-operative variables were analyzed to determine the relationship with post-operative renal function after PCNL by multivariate analysis. 202 patients were analyzed. Mean follow-up time was 16 months. At baseline, 163 (80.7%) patients were free of CKD and 39 (19.3%) had CKD. Patients without CKD had an overall decrease in GFR from 105.6 to 103.3 ml/min/1.73 m² (p = 0.494). 14/163 (8.6%) non-CKD patients experienced a significant decline in renal function after PCNL; 7/163 (4.3%) developed de novo CKD and 7 had a ≥ 30% decline in GFR. Patients with CKD had an overall increase in mean GFR post-operatively, from 47.3 to 54.0 ml/min/m² (p = 0.067). Two in this cohort (5.1%) experienced a > 30% decline in renal function post-operatively. Age, gender, African American race, presence of comorbidities and pre-operative CKD were not significant predictors of renal function post-operatively on multivariate analysis. PCNL in this cohort appears GFR neutral in the setting of baseline CKD. CKD was not predictive of renal functional decline after PCNL. Given that stone disease carries a high recurrence rate and that CKD is associated with stone formers, further investigation into predictors of renal function change after PCNL is warranted.

Single-use disposable digital flexible ureteroscopes: an ex vivo assessment and cost analysis

OBJECTIVE

To assess and measure the capability of a single-use disposable digital flexible ureteroscope, the LithoVue™ (Boston Scientific, Marlborough, MA, USA), and to assess if there is a benefit to switching to single-use scopes.

PATIENTS AND METHODS

The LithoVue was compared to two commonly used reusable flexible ureteroscopes (Olympus URF-V [Olympus, Tokyo, Japan] and Karl Storz Flex-X^c [Karl Storz & Co. KG, Tuttlingen, Germany]) ex vivo. An analysis of reusable ureteroscope usage was performed to evaluate damage, durability, and maintenance costs. This was then compared to the projected costs of using single-use disposable scopes.

RESULTS

Flexion, deflection and irrigation flow of the LithoVue was equivalent, if not better than the reusable flexible ureteroscopes. An analysis of 234 procedures with seven new Olympus URF-V scopes, revealed 15 scope damages. Staghorn stones and lower pole/mid-zone stones were significant risk factors for damage (P = 0.014). Once damage occurred it was likely to occur again. Total repair costs were $162 628 (Australian dollars) (£92 411 in Great British pounds), the mean cost per case was $695 (£395). Factoring in the purchase cost, cleaning and repair costs, the cumulative cost of 28 reusable flexible ureteroscopy procedures was ~$50 000 (£28 412). If the LithoVue was priced at $1 200 (£682), switching to a single-use scope would cost ~$35 000 (£19 888).

CONCLUSION

The LithoVue is analogous to reusable flexible ureteroscopes in regard to standard technical metrics. Depending on its purchase cost it may also represent a cost saving for hospitals when compared to the cumulative costs of maintaining reusable scopes. Additionally, urologist may consider using the scope in cases in which reusable scope damage is anticipated.

A clinical evaluation of the new digital single-use flexible ureteroscope (UscopePU3022): an international prospective multicentered study

Introduction

We assessed the clinical performance of a new digital single-use flexible ureteroscope (UscopePU3022).

Material and methods

A prospective cohort study was carried out across 11 centers (July-Oct. 2017). The UscopePU3022 was assessed regarding ease of insertion; deflection, image quality, maneuverability and overall performance using either a visual analog* or Likert scale.

Results

A total of 56 procedures were performed in 11 centers (16 surgeons) with the indication being renal stones in 83%. The median score for ease of scope insertion was 10 (3-10). Intraoperative maneuverability was rated as 'good' in 38% and 'very good' in 52%. Visual quality was rated as 'poor or bad' in 18%, 'fair' in 37% and 'good or very good' in 43%. Two scopes failed intraoperatively (4%). Preoperative and postoperative median upward and downward deflection was 270 degrees. Compared to standard flexible ureteroscopy (f-URS) maneuverability was rated as 'equivalent' in 30% and 'better' in 60%; visual quality was 'worse' in 38% and 'equivalent or better' in 62%; limb fatigue scores were 'better' in 86%; and overall performance was 'worse' in 55% and 'equivalent or better' in 45%.

Conclusions

UscopeTM3022 performed well with regards to maneuverability, deflection and limb fatigue and appears to be at least non-inferior to standard f-URS with regards to these parameters. Poor image quality is a concern for UscopePU3022 with it receiving a low overall performance rating when compared to standard f-URS. Despite this it scored highly when investigators were asked if they would use it in their practice if it was cost-effective to do so.

A New Automatically Fixating Stone Basket (2.5 F) Prototype with a Nitinol Spring for Accurate Ureteroscopic Stone Size Measurement

Introduction

Intraoperative assessment of stone size is crucial for the successful and safe extraction of stones. The first automatically fixating measuring stone basket prototype showed a mismatch between the steel spring and the nitinol basket; therefore, to improve this prototype, the steel spring was replaced with a nitinol spring and a modified scale was implemented on the basket handle for accurate intraoperative stone size measurement.

Methods

The proposed tipped basket was composed of nitinol. A standard handle with a spring-supported self-closing mechanism (2.5 F, Urotech^®) was used, and a modified nonlinear millimeter scale was established on the handle. The grasping force was provided by the new nitinol spring mechanism in the handgrip. Various colors associated with the stone size were applied on the scale.

Results

The material difference between the basket and the spring was eliminated. The measuring scale ranged from 2 mm (green) through 5 mm (yellow) to 8 mm (red), and the scale was nonlinear because of the nonlinear relationship between the diameter of the stone and the distance marked on the scale.

Conclusion

The proposed automatically fixating stone basket with a nitinol spring has the potential to improve the safety and effectiveness of endourological stone retrieval. Further validation of this new scale and basket should follow.

Exploring the Therapeutic Mechanism of Desmodium styracifolium on Oxalate Crystal-Induced Kidney Injuries Using Comprehensive Approaches Based on Proteomics and Network Pharmacology

Purpose: As a Chinese medicinal herb, Desmodium styracifolium (Osb.) Merr (DS) has been applied clinically to alleviate crystal-induced kidney injuries, but its effective components and their specific mechanisms still need further exploration. This research first combined the methods of network pharmacology and proteomics to explore the therapeutic protein targets of DS on oxalate crystal-induced kidney injuries to provide a reference for relevant clinical use.

Methods: Oxalate-induced kidney injury mouse, rat, and HK-2 cell models were established. Proteins differentially expressed between the oxalate and control groups were respectively screened using iTRAQ combined with MALDI-TOF-MS. The common differential proteins of the three models were further analyzed by molecular docking with DS compounds to acquire differential targets. The inverse docking targets of DS were predicted through the platform of PharmMapper. The protein–protein interaction (PPI) relationship between the inverse docking targets and the differential proteins was established by STRING. Potential targets were further validated by western blot based on a mouse model with DS treatment. The effects of constituent compounds, including luteolin, apigenin, and genistein, were investigated based on an oxalate-stimulated HK-2 cell model.

Results: Thirty-six common differentially expressed proteins were identified by proteomic analysis. According to previous research, the 3D structures of 15 major constituents of DS were acquired. Nineteen differential targets, including cathepsin D (CTSD), were found using molecular docking, and the component-differential target network was established. Inverse-docking targets including p38 MAPK and CDK-2 were found, and the network of component-reverse docking target was established. Through PPI analysis, 17 inverse-docking targets were linked to differential proteins. The combined network of component-inverse docking target-differential proteins was then constructed. The expressions of CTSD, p-p38 MAPK, and p-CDK-2 were shown to be increased in the oxalate group and decreased in kidney tissue by the DS treatment. Luteolin, apigenin, and genistein could protect oxalate-stimulated tubular cells as active components of DS.

Conclusion: The potential targets including the CTSD, p38 MAPK, and CDK2 of DS in oxalate-induced kidney injuries and the active components (luteolin, apigenin, and genistein) of DS were successfully identified in this study by combining proteomics analysis, network pharmacology prediction, and experimental validation.

Steep Infundibulopelvic Angle as a New Risk Factor for Flexible Ureteroscope Damage and Complicated Postoperative Course

OBJECTIVE

The increasing number of flexible ureterorenoscopy (fURS) procedures, the fragility of devices, and their growing repair costs represent a substantial burden for urological departments worldwide. No risk factors of flexible ureteroscope damage have been identified so far. The objective of this study was to investigate the impact of infundibulopelvic angle (IPA) on device damage and on other intraoperative and postoperative factors such as length of hospital stay, surgical complications, stone-free rate (SFR), operation, and fluoroscopy time.

MATERIALS AND METHODS

In a retrospective monocentric study, IPA was measured based on intraoperative retrograde pyelography images taken during fURS. All procedures were conducted with modern reusable flexible ureteroscopes: Karl Storz Flex-X2 or Olympus URF-V. Statistical analysis was performed in RStudio (version 1.0.136) with the unpaired t-test and Mann-Whitney U test. Pearson correlation coefficient (Pearson's r) was measured whenever applicable.

RESULTS

In total, 381 fURS performed between September 2013 and March 2017 were analyzed: 260 (68.24%) for kidney stone operation and 121 (31.76%) for diagnostic purposes; of these, 38 (9.97%) devices were postoperatively deemed defective. IPA values were significantly steeper in cases with flexible ureteroscope damage compared to cases without damage (median 42.5 degrees vs 56.0, p < 0.001). Steeper IPA was significantly associated with the occurrence of Clavien-Dindo ≥2 complications (median 51.0 degrees vs 55.0, p = 0.005) as well as prolonged hospital stay (median 51.0 degrees vs 55.0, p = 0.014). No influence on SFR was observed (p > 0.05). IPA did not correlate with operation or fluoroscopy time.

CONCLUSIONS

Steep IPA can be considered the first risk factor predicting both flexible ureteroscope damage and an unfavorable postoperative course. A better understanding of damage mechanisms is the key for the proper indications to use costly single-use devices.

Single-use versus reusable ureterorenoscopes for retrograde intrarenal surgery (RIRS): systematic comparative analysis of physical and optical properties in three different devices

INTRODUCTION

Retrograde intrarenal surgery (RIRS) represents a standard option for kidney stone removal. However, RIRS is considered a cost-intensive procedure. Single-use flexible ureterorenoscopes have been introduced to improve budget predictability in RIRS. We assessed differences in physical and optical properties of single-use devices compared to standard reusable endoscopes.

METHODS

In two single-use (LithoVue™, Boston Scientific; Pusen Uscope UE3011™), and one reusable ureterorenoscope (Flex-Xc™, Karl Storz), we investigated flow rates, deflection, illuminance, and intrapelvic pressure in a porcine kidney model. Subjective image quality was assessed using a standardized questionnaire. Common insertable devices were applied to investigate additional influence on physical properties.

RESULTS

Significant variability in maximum flow rates was observed (Flex-Xc™: 25.8 ml/min, LithoVue™: 30.3 ml/min, Pusen™: 33.4 ml/min, p < 0.05). Insertion of a guide wire resulted in the highest reduction of flow rates in all endoscopes. Flection led to a reduction of absolute flow rates up to 9.4% (Flex-Xc™). Light intensity at 20/50 mm distance was 9090 lx/1857 lx (Flex-Xc™) and 5733 lx/1032 lx (LithoVue™) and 2160 lx/428 lx (Pusen™), respectively (p < 0.05). Subjective image quality score was highest using the Flex-Xc™ endoscope. During manipulation, maximum intrarenal pressure up to 66 mmHg (Pusen™) was measured.

CONCLUSIONS

Significant differences in physical and optical properties of single-use or reusable flexible ureterorenoscopes are present, with putative influence on surgical efficacy and complications. Further comparative evaluation of single-use and reusable endoscopes in a clinical scenario is useful. Moreover, utilization of ureteral access sheaths may be considered to avoid renal damage.

Retrospective Cost Analysis of a Single-Center Reusable Flexible Ureterorenoscopy Program: A Comparative Cost Simulation of Disposable fURS as an Alternative

OBJECTIVE

The increasing number of flexible ureterorenoscopy (fURS) procedures, the fragility of devices, and their growing maintenance and repair costs represent a substantial burden for urologic departments. Disposable single-use fURS devices offer many advantages over reusable fURS. Among them, the LithoVue™ model shows the best clinical utility. In our study, we assessed the economic aspects of reusable fURS application compared with the potential costs and benefits of single-use fURS (LithoVue™). Indications for single-use fURS were proposed based on potential risk factors of reusable fURS damage.

MATERIALS AND METHODS

This single-center retrospective analysis compared the actual cost of reusable fURS procedures with the potential costs of LithoVue™ based on the price offered by the manufacturer. Consecutive case analysis of damaged fURS was performed to determine potential risk factors associated with fURS damage.

RESULTS

The study group consisted of 423 reusable fURS procedures conducted between January 2013 and December 2016. During this period, 102 (24.11%) diagnostic fURS and 321 (75.89%) fURS for kidney stone therapy were performed. In 32 of 423 (7.57%) fURS cases, devices were postoperatively deemed defective, 9 of which were used for diagnostic procedures (9/102; 8.82%), 7 for stone removal (7/148; 4.73%), and 16 for stone removal and laser (Ho:YAG) application (16/173; 9.25%). The average cost per reusable fURS procedure was found to be €503.26.

CONCLUSIONS

Disposable fURS is a more expensive option for high-volume centers. Based on our case analysis, laser disintegration treatment of multiple, large stones in the lower kidney pole of recurrent stone formers, as well as a steep infundibulopelvic angle (IPA ≤50°), seems to be the main risk factor for fURS damage. For these cases, disposable fURS may be a cost-effective alternative; however, a prospective comparison of economic outcomes between disposable and reusable fURS, together with confirmation of the proposed damage risk factors, is needed.

Epidemiology of paediatric renal stone disease: a 22-year single centre experience in the UK

Background

Whilst still rare, the incidence of paediatric stone disease is increasing in developed countries and it is important to evaluate the aetiology. We set up a dedicated renal stone service for children combining medical and surgical expertise in 1993 and now have a large case series of children to investigate the epidemiology.

Methods

A retrospective hospital note review of children presenting with kidney stones during the last 22 years (1993–2015) was conducted. All patients had a comprehensive infective and metabolic screen and were classified as metabolic, infective or idiopathic stone disease.

Results

Five hundred eleven patients (322 male) were reviewed. The median age of presentation was 4.4y for males (1 m-16.6y) and 7.3y (1–18.5y) for females with a median height and weight on the 25th centile for male and on 10th and 25th for female, respectively. One hundred seventy five (34%) had an underlying metabolic abnormality, 112 (22%) had infective stones and 224 (44%) were classified as idiopathic.

Of the 175 patients with a metabolic abnormality: 91 (52%) had hypercalciuria (76 persistent and 15 transient), 37 (21%) hyperoxaluria, 38 (22%) cystinuria, 3 (2%) abnormalities in the purine metabolism and the remainder other metabolic abnormalities. Bilateral stones occurred in 27% of the metabolic group compared to 16% in the non-metabolic group (OR 0.2, p < 0.05). Urinary tract infection was a common complication (27%) in the metabolic group.

Conclusions

In this paper, we present the largest cohort of paediatric stone disease reported from a developed country giving details on both, clinical and laboratory data. We show that in the majority of the patients there is an identifiable underlying metabolic and/or infective aetiology emphasizing the importance of a full work up to provide adequate treatment and prevent recurrence. Moreover, we show that stone disease in children, in contrast to the adult population, does not seem to be associated with obesity, as children have a weight below average at presentation.

Comparison of New Single-Use Digital Flexible Ureteroscope Versus Nondisposable Fiber Optic and Digital Ureteroscope in a Cadaveric Model

Purpose: To evaluate LithoVue, the new single-use digital flexible ureteroscope, in a human cadaveric model and compare it with a nondisposable fiber optic and digital flexible ureteroscopes.

Materials and Methods: LithoVue, a conventional fiber optic, and digital flexible ureteroscopes were each tested in four renal units of recently deceased female cadavers by three surgeons. The following parameters were analyzed: accessibility to the kidney and navigation of the entire collecting system with and without ureteral access sheath (UAS), lower pole access measuring the deflection of the ureteroscope with the working channel empty, and with inside two different baskets and laser fibers. A subjective evaluation of maneuverability and visibility was assessed by each surgeon at the end of every procedure.

Results: Kidney access into the Renal unit 1 was not possible without UAS for all ureteroscopes because of noncompliant ureter at the level of sacroiliac joint. The reusable digital ureteroscope was unable to reach one calix of the lower pole and one calix of the upper pole (Renal units 2 and 3) without UAS placement. Lower pole access with baskets and laser fibers was possible for each ureteroscope after UAS placement. No statistically significant differences were detected in angle deflection between ureteroscopes. The digital ureteroscope was preferred for visibility in all procedures: LithoVue for maneuverability in six procedures, fiber optic in five procedures, and the digital ureteroscope in one procedure.

Conclusions: LithoVue seems to be comparable with conventional ureteroscopes in terms of visibility and manipulation into the collecting system in fresh human cadavers. Further studies in humans are needed to determine the clinical value of this new instrument.

Kidney stones

Kidney stones are mineral deposits in the renal calyces and pelvis that are found free or attached to the renal papillae. They contain crystalline and organic components and are formed when the urine becomes supersaturated with respect to a mineral. Calcium oxalate is the main constituent of most stones, many of which form on a foundation of calcium phosphate called Randall's plaques, which are present on the renal papillary surface. Stone formation is highly prevalent, with rates of up to 14.8% and increasing, and a recurrence rate of up to 50% within the first 5 years of the initial stone episode. Obesity, diabetes, hypertension and metabolic syndrome are considered risk factors for stone formation, which, in turn, can lead to hypertension, chronic kidney disease and end-stage renal disease. Management of symptomatic kidney stones has evolved from open surgical lithotomy to minimally invasive endourological treatments leading to a reduction in patient morbidity, improved stone-free rates and better quality of life. Prevention of recurrence requires behavioural and nutritional interventions, as well as pharmacological treatments that are specific for the type of stone. There is a great need for recurrence prevention that requires a better understanding of the mechanisms involved in stone formation to facilitate the development of more-effective drugs.

Comparison of minimally invasive percutaneous nephrolithotomy and flexible ureteroscopy for the treatment of intermediate proximal ureteral and renal stones in the elderly

The aim of this study is to compare the outcomes of flexible ureteroscopy (fURS) and minimally invasive percutaneous nephrolithotomy (mPNL) for the treatment of renal and/or proximal ureteral stones sized 1-2 cm in the elderly (≥60 years). Between January 2010 and March 2015, 184 consecutive mPNL and fURS were performed to treat intermediate renal and/or proximal ureteral stones in geriatric patients. The records were retrospectively reviewed and outcomes were compared. Although no significant difference was found in the complication rate between two groups, a statistical trend (p = 0.059) in favor of fURS was observed. In addition, multivariate analysis demonstrated that mPNL, preoperative positive urine culture and lower hemoglobin were independent risk factors for postoperative complication (p = 0.016, p = 0.021, p = 0.001, respectively). And fURS was significantly associated with less hemoglobin drop, red blood cell transfusion, analgesics requirement, postoperative hospital duration, and charges of laboratory tests, medical examinations and medications (p = 0.019, p = 0.037, p = 0.006, p = 0.000 and p = 0.007, p = 0.000, p = 0.000, p = 0.001, respectively), while higher costs of operations (p = 0.008). Receiver operating characteristic curve suggested a preoperative hemoglobin of 106.5 g/L as the threshold for predicting red blood cell transfusion after mPNL. The overall one-session stone-free rate of fURS at 1 month was lower (p = 0.006), while it was similar for solitary stone between two groups. Comorbidity and previous stone surgery did not affect postoperative complication and stone-free rate. This study shows that mPNL is more effective for multiple stones, but fURS is associated with potentially less complications and postoperative hospital stay. Furthermore, preoperative hemoglobin level and urine culture can be used to predict postoperative complication risk and they may be helpful in choosing treatment methods for the elderly.

Factors Influencing Readmission after Elective Ureteroscopy

PURPOSE

Ureteroscopy is increasingly used to manage nephrolithiasis, upper urinary tract urothelial carcinoma and other urological conditions. In this study we determine the rate of readmission and emergency department visits after ureteroscopy in an underserved population, as well as factors associated with these unplanned visits.

MATERIALS AND METHODS

A retrospective chart review from 2010 to 2014 of all elective ureteroscopies was conducted at a single tertiary hospital serving an underserved population in a major metropolis. Demographic, operative and discharge characteristics were collected and analyzed.

RESULTS

A total of 276 ureteroscopies were performed with 15.6% presenting to the emergency department within 30 days. Overall 5.8% were readmitted. Readmitted patients were more likely to have hypertension (OR 3.64, p=0.02), asthma or chronic obstructive pulmonary disease (OR 5.54, p=0.001), 2 or more comorbidities (OR 3.65, p=0.12), or a complication associated with ureteroscopy (OR 7.27, p=0.007). The patients who sought care in the emergency department after ureteroscopy were less likely to have had a ureteral stent in place before ureteroscopy (OR 0.35, p=0.017) or an endoscopic urological procedure within the last 30 days (OR 0.35, p=0.045). About two-thirds of patients who presented to the emergency department complained of pain alone, while the most common complaints for readmitted patients were fever and pain (43.8%).

CONCLUSIONS

The majority of emergency department visits after ureteroscopy were due to pain. These patients were less likely to have a preoperative ureteral stent placed or a history of recent urological procedures. Readmission rates were associated with overall comorbidities and complications.