Stone centers: a national survey on surgical techniques performed in Italy.

BACKGROUND: Recurrent and complex stone disease may be considered a challenging disease. In 2018, the Calculus group of the SIU (Italian Society of Urology) set itself the goal of establishing the minimum requirements for a center that could continuously manage urolithiasis pathology, named a Stone Center. In this study we present the results of a pilot survey carried out in 2019 with the aim of drawing a map of the situation of Italian urological centers dealing with urinary stones. METHODS: A total of 260 national urology departments dealing with urolithiasis surgery were contacted for this study. A survey was issued to each of the centers to determine the number of patients treated for urinary stones and the amount of procedures performed per year: 1) extracorporeal shock wave lithotripsy ESWL; 2) ureterorenoscopy URS; 3) retrograde intrarenal surgery RIRS; 4) percutaneous nephrolithotomy PCNL. RESULTS: Out of 260 centers contacted, 188 fulfilled the survey. Outcomes were quite variable, with approximately 37% of the centers lacking a lithotripter, and 46% of those that did have it performing fewer than 100 treatments per year. In terms of endoscopic procedures, more than 80% of the centers contacted performed URS or RIRS; however, when it came to percutaneous lithotripsy, these numbers dropped significantly; 33% of the centers contacted did not perform PCNL, and of those who did, 18% had less than 5 years of experience as a center. CONCLUSIONS: Our survey shows a very heterogeneous national picture about urolithiasis treatments. Our goal is to create national paradigms to be able to define stone centers where the patient suffering from complex urinary stones can find a network of professionals with an adequate armamentarium suitable for the management of their pathology.

Trends and patterns of initial percutaneous nephrolithotomy and subsequent procedures among commercially-insured US adults with urinary system stone disease: a 10-year population-based study.

PURPOSE: To describe trends and patterns of initial percutaneous nephrolithotomy (PCNL) and subsequent procedures from 2010 to 2019 among commercially-insured US adults with urinary system stone disease (USSD). METHODS: Retrospective study of administrative data from the IBM® MarketScan® Database. Eligible patients were aged 18-64 years and underwent PCNL between 1/1/2010 and 12/31/2019. Measures of interest for analysis of trends and patterns included the setting of initial PCNL (inpatient vs. outpatient), percutaneous access (1 vs. 2-step), and the incidence, time course, and type of subsequent procedures (extracorporeal shockwave lithotripsy [SWL], ureteroscopy [URS], and/or PCNL) performed up-to 3 years after initial PCNL. RESULTS: A total of 8,348 patients met the study eligibility criteria. During the study period, there was a substantial shift in the setting of initial PCNL, from 59.9% being inpatient in 2010 to 85.3% being outpatient by 2019 (P < 0.001). The proportion of 1 vs. 2-step initial PCNL fluctuated over time, with a low of 15.1% in 2016 and a high of 22.0% in 2019 but showed no consistent yearly trend (P = 0.137). The Kaplan-Meier estimated probability of subsequent procedures following initial PCNL was 20% at 30 days, 28% at 90 days, and 50% at 3 years, with slight fluctuations by initial PCNL year. From 2010 to 2019, the proportion of subsequent procedures accounted for by URS increased substantially (from 30.8 to 51.8%), whereas SWL decreased substantially (from 39.5 to 14.7%) (P < 0.001). CONCLUSIONS: From 2010 to 2019, PCNL procedures largely shifted to the outpatient setting. Subsequent procedures after initial PCNL were common, with most occurring within 90 days. URS has become the most commonly-used subsequent procedure type.

Fluoroless Ureteroscopy: Experience in More Than 100 Patients.

BACKGROUND: Ureteroscopy is becoming the primary treatment for ureteral stones. As a standard of care, ureteroscopy is performed under the supervision of fluoroscopy. Recent advances in endourological technology make the need for fluoroscopy questionable. OBJECTIVES: To summarize our experience with a no-fluoroscopy technique for selected cases of ureteral stones. METHODS: Patients were considered suitable for fluoroless ureteroscopy if they had one or two non-impacted stones, in any location in the ureter, 5-10 mm size, with a normal contralateral renal unit and no urinary tract infection. Procedures were performed using rigid scopes, nitinol baskets/forceps for stone retrieval, and Holmium:YAG laser for lithotripsy. Stents were placed per surgeon's decision. RESULTS: During an 18-month period, 103 patients underwent fluoroless ureteroscopy. In 94 patients stones were removed successfully. In six, the stones were pushed to the kidney and treated successfully on a separate session by shock wave lithotripsy. In three patients no stone was found in the ureter. In five patients, miniature perforations in the ureter were noted and an indwelling double J stent was placed. CONCLUSIONS: Fluoroless ureteroscopy resulted in a high rate of success. We believe that in selected cases it can be used with minimal adverse events.

Contemporary treatment trends for upper urinary tract stones in a total population analysis in Germany from 2006 to 2019: will shock wave lithotripsy become extinct?

PURPOSE: To describe the change in upper urinary tract stone management in Germany over a 14-year period. METHODS: Using remote data processing we analyzed the nationwide German billing data from 2006 to 2019. To analyze the clinics' case numbers and regional trends, we used the reimbursement.INFO tool based on standardized quality reports of all German hospitals. To also cover shock wave lithotripsy (SWL) as an outpatient procedure, we analyzed the research database of the Institute for Applied Health Research with a representative anonymous sample of 4 million insured persons. RESULTS: The number of inpatient interventional therapies for upper tract urolithiasis in Germany increased from 70,099 cases in 2006 to 94,815 cases in 2019 (trend p < 0.0001). In-hospital SWL declined from 41,687 cases in 2006 to 10,724 cases in 2019 (decline of 74%; trend p < 0.0001). The percentage of SWL as an outpatient procedure increased between 2013 and 2018 from 36 to 46% of all performed SWL, while total SWL case numbers declined. Contrarily, the number of ureteroscopies increased from 32,203 cases in 2006 to 78,125 cases in 2019 (increase of 143%; trend p < 0.0001). The number of percutaneous nephrolithotomy also increased from 1673 cases in 2006 to 8937 in 2019 (increase of 434%; trend p < 0.0001). CONCLUSION: We observed an increase in interventional therapy for upper tract urolithiasis in Germany with a dramatic shift from SWL to endoscopic/percutaneous treatment. These changes may be attributed to enormous technological advances of the endoscopic armamentarium and to reimbursement issues.

Natural History of Post-Treatment Kidney Stone Fragments: A Systematic Review and Meta-Analysis.

PURPOSE: We assessed the literature around post-treatment asymptomatic residual stone fragments and performed a meta-analysis. The main outcomes were intervention rate and disease progression. MATERIALS AND METHODS: We searched Ovid®, MEDLINE®, Embase™, the Cochrane Library and ClinicalTrials.gov using search terms: "asymptomatic", "nephrolithiasis", "ESWL", "PCNL", "URS" and "intervention." Inclusion criteria were all studies with residual renal fragments following treatment (shock wave lithotripsy, ureteroscopy or percutaneous nephrolithotomy). Analysis was performed using 'metafor' in R and bias determined using Newcastle-Ottawa scale. RESULTS: From 273 articles, 18 papers (2,096 patients) had details of intervention rate for residual fragments. Aggregate intervention rates for ≤4 mm fragments rose from 19% (20 months) to 22% (50 months), while >4 mm fragments rose from 22% to 47%. Aggregate disease progression rates for ≤4 mm rose from 25% to 47% and >4 mm rose from 26% to 88%. However, there was substantial difference in definition of "disease progression." Meta-analysis comparing >4 mm against ≤4 mm fragments: intervention rate for >4 mm (vs ≤4 mm): OR=1.50 (95% CI 0.70-2.30), p <0.001, I2=67.6%, tau2=0.48, Cochran's Q=11.4 (p=0.02) and Egger's regression: z=3.11, p=0.002. Disease progression rate for >4 mm: OR=0.06 (95% CI -0.98-1.10), p=0.91, I2=53.0%, tau2=0.57, Cochran's Q=7.11 (p=0.07) and Egger's regression: z=-0.75, p=0.45. Bias analysis demonstrated a moderate risk. CONCLUSIONS: Larger post-treatment residual fragments are significantly more likely to require further intervention especially in the long term. Smaller fragments, although less likely to require further intervention, still carry that risk. Notably, there is no significant difference in disease progression between fragment sizes. Patients with residual fragments should be appropriately counselled and informed decision-making regarding further management should be done.

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.

Impacts of the COVID-19 outbreak on visits and treatments for patients with ureteral stones in a general hospital emergency department.

BACKGROUND: The COVID-19 is a challenge for both patients and physicians in emergency department (ED). This study was aimed to report the impacts of the COVID-19 outbreak on visits and treatments for patients with ureteral stones in a general hospital ED. METHODS: The patients with ureteral stones were collected from 24 January to 24 March 2020 during the COVID-19 outbreak in Beijing. Two periods were divided for study: 24 January to 24 February (Period 1) and 25 February to 24 March (Period 2). Data on patients' characteristics, attendance, visual analog scale (VAS) scores, stone features, and final treatment choices were retrieved from the computer and compared with the data in the same periods in 2019. RESULTS: The study included 376 patients with ureteral stones during the COVID-19 outbreak periods in 2020 and 343 patients during the same periods in 2019. Compared with the same periods in 2019, the number of patients with ureteral stones was less in Period 1 (137 vs 163) but had a rebound phenomenon in Period 2 (239 vs 180). The visit frequency was significantly reduced (2.6 ± 0.4 vs 3.6 ± 0.8, p < 0.01) and the VAS scores and the onset time increased (7.7 ± 1.3 vs 5.5 ± 1.6, p < 0.01; 7.4 ± 1.8 vs 8.2 ± 1.5, p < 0.01, respectively) in Period 1. More patients chose oral analgesics medication to release from renal colic in the COVID-19 outbreak period instead of ESWL and intravenous analgesics medication (Period 1, 54.0% vs 20.2%, p < 0.01; Period 2, 20.9% vs 13.3%, p = 0.044; respectively). However, the percentage of patients underwent endoscopy surgery in outbreak period showed no significant difference compared with that in 2019. CONCLUSION: These results showed that the COVID-19 outbreak can directly affect the visits and final treatment choices for patients with ureteral stones.

Factors affecting success in the treatment of proximal ureteral stones larger than 1 cm with extracorporeal shockwave lithotripsy in adult patients.

The aim of the study was to analyze the factors predicting success for the treatment of proximal ureteral stones larger than 1 cm with extracorporeal shockwave lithotripsy (SWL) in adult patients. Between January 2014 and December 2018, 480 adult patients in total underwent SWL and data were retrospectively evaluated. Patients with multiple ureteral stones, solitary kidney, congenital abnormality, skeletal system abnormality, history of previous urinary system surgery and SWL, renal insufficiency, patients who could not tolerate SWL and pediatric patients were excluded from the study. The remaining 415 patients were divided into two groups as success (Group 1, n = 307) and failure (Group 2, n = 108). The overall success rate was 73.9%. The values of stone size, Hounsfield Unit (HU), skin to stone distance (SSD), ureteral wall thickness (UWT), proximal ureter diameter, renal pelvis diameter, hydronephrosis grade, and duration of renal colic were significantly higher in Group 2 compared to Group 1. In binary logistic regression analyses, HU, UWT, and proximal ureter diameter were found to be independent predictors. HU, UWT, and proximal ureter diameter had sensitivity and specificity of 92-92%, 88-23%, and 87-46%, with cutoff values of 740 HU, 2.5 mm and 8.5 mm, respectively. The area under the curve values were 0.96, 0.97, and 0.96 for HU, UWT, and proximal ureter diameter, respectively. The CT-based parameters, including HU, UWT, and proximal ureter diameter are independent predictive factors with excellent accuracy for the treatment of proximal ureteral stones larger than 1 cm with SWL in adult patients. Based on these factors, SWL can be considered for proximal ureteral stones larger than 1 cm.

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.

Decreased Recurrence of Urolithiasis After Simultaneous Ureteroscopic Surgery for Ureter and Ipsilateral Renal Calculi: Comparison to Shockwave Lithotripsy for Ureter Calculi Alone.

OBJECTIVE: To compare follow-up outcomes of ureteroscopy (URS) and shockwave lithotripsy (SWL) for ureter calculi in the setting of asymptomatic renal calculi <15 mm. METHODS: This study included 789 patients who underwent URS (n = 301) or SWL (n = 488) as primary treatment for ureter calculi and who had ipsilateral renal calculi <15 mm between January 2012 and December 2019. For the URS group, all renal calculi were simultaneously treated unless contraindicated. One-to-one matching was performed using the propensity score (PS). RESULTS: After PS matching, analysis included 262 matched pairs of URS and SWL patients. The stone-free rate for ureter calculi without auxiliary procedure was 97.3% in the URS group and 93.9% in the SWL group. Any complication rates were 11.0% and 9.2% in the URS and SWL group, respectively; 1.1% of the URS patients experienced complications classified as Clavien-Dindo ≥IIIb. The estimated 2-year intervention-free survival was 88.1% in the URS group and 84.2% in the SWL group (P = 0.045). The estimated 2-year stone-event-free survival was 80.1% in the URS group and 71.0% in the SWL group (P = 0.009). Cox multivariate analysis showed that the hazard ratios of URS were 0.62 (P = 0.025) for surgical interventions and 0.64 (P = 0.008) for stone-related events after adjusting for baseline variables. CONCLUSION: For patients with symptomatic ureter calculi and asymptomatic renal calculi <15 mm, URS with active treatment for renal calculi reduces future ipsilateral surgical intervention and stone-related events compared with SWL for ureter calculi.

Usability of shear wave elastography to predict the success of extracorporeal shock-wave lithotripsy: prospective pilot study.

The present study is intended to investigate the usability of shear wave elastography (SWE) in predicting the success of extracorporeal shock-wave lithotripsy (ESWL) used in kidney stone treatment. ESWL was performed on a total number of 52 patients diagnosed with kidney stones between May 2019 and July 2020. The presence of a residual stone greater than 4 mm was accepted as failure. The patients were divided into two groups as ESWL success and ESWL failure. SWE and Hounsfield unit (HU) measurements of stones were performed in all patients before ESWL. The two groups were compared in terms of age, gender, stone localisation, stone size, body mass index (BMI), skin-to-stone distance, HU, and SWE values of the stones. ESWL was successful in 30 of the 52 patients included in the study, while it failed in 22 of them. While the mean SWE value was 7.3 (7.9 ± 2.2) kPa in patients with success in ESWL, it was 14.6 (17.9 ± 10.2) kPa in those with failed ESWL. The mean HU was 883.5 (841.4 ± 191.1) in patients with success in ESWL and 1078 (1115.5 ± 183) in those with failed ESWL. Both SWE and HU values of the stones were found to be statistically significantly lower in the successful group (p < 0.05). It was seen that SWE and HU values were correlated to each other. The groups of successful and failed ESWL did not differ significantly in terms of age, gender distribution, stone size, BMI, and skin-to-stone distance (p > 0.05). With SWE, the hardness of the stone can be measured and its suitability for ESWL can be evaluated. It can be used as an alternative parameter to HU before ESWL treatment, since it has a lower cost compared to computed tomography (CT) and does not contain radiation.

The Risk Factors of Febrile Urinary Tract Infection After Ureterorenoscopic Lithotripsy.

We aimed to evaluate the risk factors for febrile urinary tract infection (fUTI) following ureterorenoscopic lithotripsy (URSL) for upper urinary tract stones. We retrospectively reviewed the data of 109 patients with upper urinary tract stones who underwent URSL at our hospital from October 2016 to March 2019. We divided the patients into two groups: those who developed fUTI after URSL (fUTI group) and those who did not (non-fUTI group). The retrospectively collected data, including age, sex, body mass index (BMI), mobility, diabetes mellitus, operative duration, preoperative ureteral stent placement, number of stones, stone diameter, CT value of stone, stone location, preoperative UTI, preoperative urine culture, preoperative pyelonephritis, and stone-free status were compared between the two groups. Postoperative fUTI occurred in three of the 109 patients (2.8%). Comparing the two groups, a significant risk factor for developing fUTI after URSL was a low BMI. However, in our study, only three cases developed fUTI after URSL; thus, a multivariate analysis could not be performed. One of the three cases in which fUTI occurred was accompanied by anorexia nervosa and an extremely low BMI of 11 kg/m². In summary, even though we had only 3 fUTI patients and did not perform multivariate analysis, our data suggested a significant risk factor for developing fUTI was a low BMI. Increasing the sample size, and further study seem desirable.

Treatment Setting Influences Treatment Modality for Urinary Stone Disease.

OBJECTIVE: To determine whether selection of treatment modality for urinary stone disease differs between primary and outreach healthcare centers, and if patient rurality predicts treatment modality. METHODS: We retrospectively evaluated Extracorporeal shock wave lithotripsy (ESWL) and ureteroscopy (URS) procedural data from the Iowa Office of Statewide Clinical Education Programs (OSCEP) and Iowa Hospital Association (IHA) databases from 2007 to 2014. Geographical data was used to analyze travel metrics and patient proximity to sites of stone treatment. Rural-urban commuting area (RUCA) codes were used to characterize patient rurality. Chi-square tests and t tests were used to compare ESWL and URS patients, and multilevel logistic regression model was used to assess influence of treatment setting on surgical modality. RESULTS: A total of 18,831 stone procedures were performed by urologists in Iowa on patients from Iowa (10,495 URS; 8336 ESWL). Around 2630 procedures occurred at outreach centers. Ureteroscopy comprised 59.7% of procedures at primary centers, but only 31.2% at outreach centers. On multilevel analysis, outreach location was associated with 2.236 OR toward ESWL (P <.001). Individual physician treatment patterns accounted for 32% of treatment variation. Patient rurality was not significantly associated with treatment modality as an independent factor (P = .879). CONCLUSIONS: Wide variation exists in urolithiasis treatment modality selection between outreach and primary centers. Outreach locations perform a significantly higher frequency of ESWL compared to URS, and much of the variation in treatment selection (32%) arises from individual physician practice patterns.

Shockwave Lithotripsy Use in the State of Michigan: American Urological Association Guideline Adherence and Clinical Implications.

OBJECTIVE: To understand how treatment of patients with urinary stones by shockwave lithotripsy (SWL) aligns with current published practice guidelines. METHODS: We used the Michigan Urologic Surgery Improvement Collaborative Reducing Operative Complications for Kidney Stones registry to understand SWL use in the state of Michigan. This prospectively maintained clinical registry includes data from community and academic urology practices and contains clinical and operative data for patients undergoing SWL and ureteroscopy (URS). We identified patients undergoing SWL from 2016 to 2019. In accordance with AUA guidelines, we evaluated practice patterns in relation to recommendations for treatment selection for SWL as well as clinical implications of guideline nonadherence. RESULTS: Four thousand, two hundred and nine SWL procedures performed across 34 practices were analyzed. Perioperative antibiotics were administered to 61.3% of patients undergoing SWL. A ureteral stent was placed at the time of SWL in 2.7% of patients. For lower pole renal stones >1 cm or large (>2 cm) renal stones in the registry, 32.2% and 58.9% of patients, respectively, underwent SWL, while the remainder were treated with URS. In these instances, SWL was associated with inferior stone-free rate (SFR) relative to URS. In patients with residual stones after SWL, 34.6% were treated with repeat SWL with lower SFR than those treated with subsequent URS. Postoperatively, 42.1% of patients were prescribed alpha-blockers with no benefit seen in terms of SFR. CONCLUSION: Substantial variation exists among urology practices with regard to SWL use. These data serve to inform quality improvement efforts regarding appropriateness criteria for SWL in Michigan.

Is There Any Improvement In Efficacy Of Xtracorporeal Shockwave Lithotripsy Therapy For Treating Renal Stones With Invent Of New Shockwave Machines?

BACKGROUND: Renal stone disease is a very common medical problem in general population. As with invent of newer therapeutic modalities, ESWL is already losing its popularity. But we believe it as an effective way of treating renal stones. This study was conducted to evaluate any improvement in success rate of ESWL therapy for treating renal stones with latest shockwave lithotripsy machines. METHODS: Study conducted from June 2016 until November 2017 in Alkhor hospital, Hamad Medical Corporation, Qatar. All patients undergoing ESWL for renal stones in mentioned period were included. Total 197 patients underwent ESWL using newer machines. Factors already studied to affect the success rate like stone size, location, consistency (measured by Hounsfield units on CT), presence of stent were taken in consideration. After a period of 3 months either complete stone clearance or stone fragments smaller than 4 mm were considered as a treatment success. These results were compared to the results from literature. RESULTS: Patients were followed until 3 months after treatment. 170 patients (86.29%) had complete stone clearance. Eleven patients (5.58%) had residual stone less than 4 mm, thus achieving an overall success of 181 patients (91.88%). 42 patients (21.32%) needed repeat session of ESWL with a maximum number of 3 sessions. 16 patient's (8.12%) required auxiliary procedures like flexible ureteroscopy. Post-ESWL complications were recorded in 12 patients (6.09%). Success rate was affected mainly by stone size with negligible effect of stone location. Presence of stent affected the number of sessions but has no impact on stone clearance.. CONCLUSIONS: Although the stone size and to a negligible extent, the stone location and presence of stent may affect the stone clearance, nevertheless a significant improvement in success rate has been observed by use of new shockwave lithotripsy machines.

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.

The impact of potassium citrate therapy in the natural course of Medullary Sponge Kidney with associated nephrolithiasis.

OBJECTIVES: The present study was carried out to evaluate the effectiveness of medical therapy with potassium citrate in preventing calculosis complicating Medullary Sponge Kidney (MSK) without renal acidification defects. MATERIALS AND METHODS: In a open, uncontrolled, retrospective analysis, 49 MSK patients with nephrolithiasis without renal tubular acidosis, underwent a complete metabolic evaluation and received potassium citrate therapy 4-6 g/day. The course of stone disease before and after citrate therapy was determined in each patient from a combination of clinical history, past records, radiographs and kidney ultrasound. The rate of new stone formation/pt/yr, of endourological and extracorporeal procedures, of urinary tract infection (UTI) and number of hospitalization before and after medical treatment were calculated. RESULTS: Metabolic anomalies (hypercalciuria, hypocitraturia, hyperuricuria and hyperoxaluria) were present in 83% of the patients. Follow-up before and after alkali citrate therapy was comparable (4.7+/-1.4 and 4.9+/-1.7 years respectively). Medical treatment significantly reduced rates of stone formation from 2.0+/-1.0 to 0.2+/-0.5 pt/yr, ureteroscopy (URS) from 0.9+/0.8 to 0.4+/-0.5 pt/yr, extratracoporeal lithotripsy (ESWL) from 1.1+/-0.8 to 0.4+/-0.6 pt/yr, urinary tract infections (UTIs) from 0.8+/-1.2 to 0.3+/-0.5 pt/yr and hospitalization from 1.1+/-0.6 to 0.2+/-0.3 pt/yr, p < 0.001. This effect was observed also in MSK patients without metabolic anomalies. In 35 patients the asymptomatic disappearance of calcium stones was also observed. CONCLUSIONS: Our study documents the effectiveness of potassium citrate therapy in preventing neprolithiasis in MSK patients also in the absence of distal tubular acidosis. It suggests that in MSK patients alkali citrate may promote calcium stone dissolution by oral administration.

Clinical and demographic predictors of repeat stone surgery.

OBJECTIVE: To identify the clinical and demographic predictors of repeat stone surgery. MATERIALS AND METHODS: We retrospectively analysed 1496 consecutive patients, aged > 18 years, who underwent stone surgery at our institution in the period from January 2009 to May 2017 and who had at least 12 months of postoperative follow-up. We defined surgical recurrence as repeat surgery on the same renal unit or on the opposite renal unit if the original imaging did not demonstrate significant stones on that side. Characteristics associated with the risk of surgical recurrence in univariate Cox regression analysis were entered into a multivariate model. RESULTS: Most patients underwent ureteroscopy and laser lithotripsy (83.0%). Approximately 60% of the patients had a personal history of stone disease and 50% were obese. Over a mean (median; interquartile range) follow-up of 4.1  (3.9; 2.4-5.9) years, 24.5% of patients had surgical recurrence, with 82% of repeat surgeries performed for symptomatic nephrolithiasis. The factors associated with increased risk of surgical recurrence in the multivariate model were: age <60 years, female gender, malabsorptive gastrointestinal disease, diabetes, recurrent urinary tract infections, personal history of nephrolithiasis, renal stones and bilateral nephrolithiasis. The hazard ratios for these variables ranged within an interval of <0.5 (from 1.30 to 1.71). CONCLUSION: We identified eight demographic and clinical factors associated with increased risk of repeat renal stone surgery. These factors could be combined as a numerical count that allows stratification of patients into low-, intermediate- and high-risk subgroups.

The Durability of Active Surveillance in Patients with Asymptomatic Kidney Stones: A Systematic Review.

Introduction: The natural progression of asymptomatic kidney stones remains unclear. Such knowledge may promote value-aligned care for patients and reduce potentially unnecessary procedures. We sought to evaluate the natural history of asymptomatic kidney stones in adults undergoing active surveillance. Materials and Methods: Using themes of "Kidney Stone" and "Active Surveillance," we performed a systematic review by searching for studies in MEDLINE, all Cochrane libraries, EMBASE, Cumulative Index to Nursing and Allied Health Literature, BIOSIS, Scopus, and Web of Science from inception through October 2017-in addition to ClinicalTrials.gov, American Urological Association Annual Meeting abstracts (2014-2017), Google Scholar, and references of included studies and prior reviews. Two blinded reviewers independently extracted data and assessed methodological quality. We qualitatively summarized rates of surgical intervention (primary outcome), spontaneous stone passage, symptom development, and stone growth. We assessed the relationship between surveillance duration and rate of surgical intervention with Pearson's correlation coefficient. Results: Of 7034 unique records, 13 studies met final eligibility criteria. There was substantial variation in reported rates of surgical intervention from 6/85 (7.1%) to 80/301 (26.6%), spontaneous stone passage from 1/32 (3.1%) to 101/347 (29.1%), symptom development from 7/96 (7.3%) to 231/300 (77.0%), and stone growth from 5/96 (5.2%) to 33/50 (66.0%). Mean surveillance duration spanned from 11.3 to 80 months (range 2-180 months). Longer mean duration of surveillance did not correlate with an increase in surgical intervention rate across studies (n = 13, r = 0.01, p = 0.98), and this finding persisted when restricting analysis to observational studies (n = 9, r = 0.12, p = 0.76). Conclusions: Active surveillance appears to be a durable strategy for a majority of patients with asymptomatic kidney stones, as there was no increase in failure of watchful waiting despite increasing duration of surveillance. Higher quality studies are needed to ascertain which patients may benefit most from active surveillance.