The impact of kidney stone disease on quality of life in high-risk stone formers.

OBJECTIVE: To assess the impact of kidney stone disease (KSD) and its treatment on the health-related quality of life (HRQOL) of high-risk stone formers with hyperparathyroidism, renal tubular acidosis, malabsorptive disease, and medullary sponge kidney. PATIENTS AND METHODS: The Wisconsin Stone Quality of Life questionnaire was used to evaluate HRQOL in 3301 patients with a history of KSD from 16 institutions in North America between 2014 and 2020. Baseline characteristics and medical history were collected from patients, while active KSD was confirmed through radiological imaging. The high-risk group was compared to the remaining patients (control group) using the Wilcoxon rank-sum test. RESULTS: Of 1499 patients with active KSD included in the study, the high-risk group included 120 patients. The high-risk group had significantly lower HRQOL scores compared to the control group (P < 0.01). In the multivariable analyses, medullary sponge kidney disease and renal tubular acidosis were independent predictors of poorer HRQOL, while alkali therapy was an independent predictor of better HRQOL (all P < 0.01). CONCLUSIONS: Among patients with active KSD, high-risk stone formers had impaired HRQOL with medullary sponge kidney disease and renal tubular acidosis being independent predictors of poorer HRQOL. Clinicians should seek to identify these patients earlier as they would benefit from prompt treatment and prevention.

Diagnosis and management of primary hyperoxalurias: best practices.

The primary hyperoxalurias (PH 1, 2, and 3) are rare autosomal recessive disorders of glyoxylate metabolism resulting in hepatic overproduction of oxalate. Clinical presentations that should prompt consideration of PH include kidney stones, nephrocalcinosis, and kidney failure of unknown etiology, especially with echogenic kidneys on ultrasound. PH1 is the most common and severe of the primary hyperoxalurias with a high incidence of kidney failure as early as infancy. Until the recent availability of a novel RNA interference (RNAi) agent, PH care was largely supportive of eventual need for kidney/liver transplantation in PH1 and PH2. Together with the Oxalosis and Hyperoxaluria Foundation, the authors developed a diagnostic algorithm for PH1 and in this report outline best clinical practices related to its early diagnosis, supportive treatment, and long-term management, including the use of the novel RNAi. PH1-focused approaches to dialysis and kidney/liver transplantation for PH patients with progression to chronic kidney disease/kidney failure and systemic oxalosis are suggested. Therapeutic advances for this devastating disease heighten the importance of early diagnosis and informed treatment.

MAGNESIUM SUPPLEMENTATION INCREASES URINE MAGNESIUM AND CITRATE IN STONE FORMERS WITH HYPOMAGNESURIA.

OBJECTIVES: To compare the effects of magnesium repletion by a foods-alone approach or by magnesium supplementation on urinary magnesium and citrate excretion in patients with urine magnesium <70 mg/day. METHODS: We reviewed medical records of patients in our stone prevention practice who were advised to start a magnesium supplement (Sup), 250-500 mg/d, or increase dietary magnesium consumption. We included adults with 24h UMg <70 mg, those who received magnesium recommendations (corroborated by the dietitian's clinical notes), and those with a follow-up 24h urine collection ≤18 months. Urine results were assessed by group. RESULTS: Groups [No Sup (n=74) and Sup (n=56)] were not different for age, gender, stone history, malabsorption, or other clinical indices. All patients raised UMg (53 to 69 and 47 to 87 mg/d for No Sup and Sup, respectively); however, the increase was significantly higher in the Sup group. Moreover, while 88% of Sup patients achieved UMg ≥70 mg/d, only 58% in the No Sup group did so. Within-group increases in urine citrate were significant only in the Sup group. CONCLUSION: Among patients with low UMg, both higher consumption from foods and magnesium supplementation significantly increased UMg. However, those who supplemented were significantly more likely to reach or exceed UMg 70 mg/d and achieved higher mean UMg. The change in urine citrate was significant only among those in the Sup group.

Pulse-modulated Holmium:YAG Laser vs the Thulium Fiber Laser for Renal and Ureteral Stones: A Single-center Prospective Randomized Clinical Trial.

PURPOSE: We sought to compare the clinical effectiveness of the pulse-modulated Ho:YAG (holmium:yttrium-aluminum-garnet) laser and the thulium laser fiber for ureteroscopic stone management in a randomized clinical trial. The primary outcome was the ureteroscope time required to adequately fragment stones to 1 mm or less. Secondary outcomes were stone-free rate, complications, subjective surgeon measurement of laser performance, patient related stone quality of life outcomes, and measurements of laser efficiency. MATERIALS AND METHODS: An Institutional Review Board-approved randomized clinical trial was conducted to randomize patients to outpatient treatment with either the Moses 2.0 or thulium laser fiber in a 1:1 manner after stratification into groups based on the maximal diameter of treated stone (3-9.9 mm or 10-20 mm). Patient, stone, and operative parameters were compared using the appropriate categorical/continuous and parametric/nonparametric statistical tests (SPSS 25). RESULTS: From July 16, 2021 to March 11, 2022, 108 patients were randomized and had primary endpoint data available for analysis; 52 patients were randomized to Ho:YAG and 56 patients to thulium laser fiber. Groups were well balanced with no significant differences observed for patient or stone characteristics. Ureteroscope time was not significantly different between modalities (Ho:YAG mean 21.4 minutes vs thulium laser fiber mean 19.9 minutes, P = .60), or within subgroup analysis by stone size, median Hounsfield units, or stone location. There were no significant differences observed in the stone-free rate and complications rate between the 2 lasers. CONCLUSIONS: This randomized clinical trial suggests no significant clinical advantage of one laser technology over the other. Surgeon and institutional preference are the best approach when selecting one or the other.

Primary Contributors to Dietary Acid Load in Patients With Urolithiasis.

OBJECTIVES: In susceptible individuals, high dietary acid load may contribute to the formation of certain types of kidney stones via lowering urine pH and citrate excretion. The objective of this study is to determine the contribution of dietary acid from food groups in people with urolithiasis. DESIGN AND METHODS: Patients with calcium urolithiasis (n = 83) who completed food records were used for this retrospective analysis. Descriptive statistics were calculated for nutrients, potential renal acid load (PRAL), and estimated net endogenous acid production (NEAPest). Pearson's correlations were calculated between PRAL and NEAPest with each nutrient. RESULTS: Data from a total of 83 patients were used. Average PRAL was positively correlated with energy (r = 0.260, P = .02), total protein (r = 0.463, P < .001), animal protein (r = 0.555, P < .001), total fat (P = .399, P < .001), sodium (r = 0.385, P < .001), and phosphorus (r = 0.345, P < .001) intake. PRAL was negatively correlated with fiber (r = -0.246, P = .03) intake. NEAPest was positively correlated with total protein (r = 0.269, P = .01), animal protein (r = 0.377, P < .001), fat (r = 0.222, P = .04), and sodium (r = 0.250, P = .02) intake. NEAPest was negatively correlated with fiber (r = -0.399, P < .001), potassium (r = -0.360, P < .001), and magnesium (r = -0.233, P = .03) intake. For PRAL, meat contributed the highest acid load (52.7%), followed by grains (19.6%) and combination foods (19.6%). Beverages contributed the greatest alkali load (35.1%), followed by vegetables (30.6%) and fruits (28.6%). For NEAPest, cheese contributed the highest acid load (21.8%), followed by grains (19.3%) and meat (18.1%). CONCLUSIONS: For individuals with urolithiasis promoted by acidic urine and/or low urine citrate, dietary patterns with a high dietary acid load may contribute to recurrence risk. Meat and grains were the major contributors to dietary acid load in this cohort of patients with a history of kidney stones, whereas beverages, fruits, and vegetables contributed net alkali.

Estimating the health-related quality of life of kidney stone patients: initial results from the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA).

OBJECTIVE: To build the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA) to predict urolithiasis patients' health-related quality of life (HRQoL) based on demographic, symptomatic and clinical data collected for the validation of the Wisconsin Stone Quality-of-Life (WISQOL) questionnaire, an HRQoL measurement tool designed specifically for patients with kidney stones. MATERIAL AND METHODS: We used data from 3206 stone patients from 16 centres. We used gradient-boosting and deep-learning models to predict HRQoL scores. We also stratified HRQoL scores by quintile. The dataset was split using a standard 70%/10%/20% training/validation/testing ratio. Regression performance was evaluated using Pearson's correlation. Classification was evaluated with an area under the receiver-operating characteristic curve (AUROC). RESULTS: Gradient boosting obtained a test correlation of 0.62. Deep learning obtained a correlation of 0.59. Multivariate regression achieved a correlation of 0.44. Quintile stratification of all patients in the WISQOL dataset obtained an average test AUROC of 0.70 for the five classes. The model performed best in identifying the lowest (0.79) and highest quintiles (0.83) of HRQoL. Feature importance analysis showed that the model weighs in clinically relevant factors to estimate HRQoL, such as symptomatic status, body mass index and age. CONCLUSIONS: Harnessing the power of the WISQOL questionnaire, our initial results indicate that the WISQOL-MLA can adequately predict a stone patient's HRQoL from readily available clinical information. The algorithm adequately relies on relevant clinical factors to make its HRQoL predictions. Future improvements to the model are needed for direct clinical applications.

Sulfamethoxazole-induced sulfamethoxazole urolithiasis: a case report.

BACKGROUND: Drug-induced urolithiasis falls into two categories: drug-induced and metabolically-induced. Certain antimicrobials are associated with each; sulfonamides are associated with drug- or metabolite-containing calculi when taken in large doses over a long period of time. Trimethoprim-sulfamethoxazole, a member of the sulfonamide family, is a rare cause of drug-induced calculi. Cases of sulfonamide urolithiasis occurring in patients with known stone disease have rarely been reported. CASE PRESENTATION: We report a case of a patient with a brief history of recurrent calcium oxalate nephrolithiasis requiring 2 ureteroscopic procedures whose existing 6 mm lower pole renal stone more than quadrupled in size to form a 4 cm renal staghorn after 4 months of high-dose treatment for Nocardia pneumonia with trimethoprim-sulfamethoxazole. After ureteroscopy with laser lithotripsy and basketing of fragments, the stone was found to be predominantly composed of N4-acetyl-sulfamethoxazole, a metabolite of sulfamethoxazole. CONCLUSION: Stones composed of sulfamethoxazole or its metabolites are rare but have known associated risk factors that should be considered when prescribing this antibiotic. This case report illustrates additional risk factors for consideration, including pre-existing urinary calculi that may serve as a nidus for sulfamethoxazole deposition, and reviews treatment and prevention methods.

Effect of stone composition on surgical stone recurrence: single center longitudinal analysis.

INTRODUCTION The objective of this study is to explore the association between urinary stone composition and surgical recurrence. MATERIALS AND METHODS: Patients who underwent kidney stone surgeries (between 2009-2017), were followed for > 1 year, and had ≥ 1 stone composition analyses were included in our analysis. Surgical stone recurrence (repeat surgery) was defined as the second surgery on the same kidney unit. Recurrence-free survival analysis was used. RESULTS: A total number of 1051 patients were included (52.7% men, average age 59.1 +/- 15.1 years). Over 4.7 +/- 2.5 years follow up, 26.7% of patients required repeat surgery. Patients' stone compositions were calcium oxalate (66.0%), uric acid (12.2%), struvite (10.0%), brushite (5.7%), apatite (5.1%) and cystine (1.0%). Results suggested that patients with cystine stones had the highest surgical recurrence risk; brushite had the second-highest surgical recurrence risk. Struvite, uric acid, and apatite stones were at higher risk compared with calcium oxalate stones (lowest risk in our cohort). When pre and postoperative stone size was controlled, patients with a history of uric acid, brushite, and cystine stones were at higher surgical risk. After controlling clinical and demographic factors, only brushite and cystine stones were associated with higher surgical recurrence. CONCLUSIONS: Patients with cystine stones had the highest surgical recurrence risk; brushite stones had the second highest surgical recurrence risk. Struvite, uric acid, and apatite stones were at higher risk compared with calcium oxalate stones. When pre and postoperative stone size, clinical and demographic factors were controlled, only those with brushite or cystine stones were at significantly higher risk of surgical recurrence.

Inhibition of urinary stone disease by a multi-species bacterial network ensures healthy oxalate homeostasis.

The incidence of urinary stone disease is rapidly increasing, with oxalate being a primary constituent of approximately 80% of all kidney stones. Despite the high dietary exposure to oxalate by many individuals and its potential nephrotoxicity, mammals do not produce enzymes to metabolize this compound, instead relying in part on bacteria within the gut to reduce oxalate absorption and urinary excretion. While considerable research has focused on isolated species of oxalate-degrading bacteria, particularly those with an absolute requirement for oxalate, recent studies have pointed to broader roles for microbiota both in oxalate metabolism and inhibition of urinary stone disease. Here we examined gut microbiota from patients with and live-in individuals without urinary stone disease to determine if healthy individuals harbored a more extensive microbial network associated with oxalate metabolism. We found a gender-specific association between the gut microbiota composition and urinary stone disease. Bacteria enriched in healthy individuals largely overlapped with those that exhibited a significant, positive correlation with Oxalobacter formigenes, a species presumed to be at the center of an oxalate-metabolizing microbial network. Furthermore, differential abundance analyses identified multiple taxa known to also be stimulated by oxalate in rodent models. Interestingly, the presence of these taxa distinguished patients from healthy individuals better than either the relative abundance or colonization of O. formigenes. Thus, our work shows that bacteria stimulated by the presence of oxalate in rodents may, in addition to obligate oxalate users, play a role in the inhibition of urinary stone disease in man.

Role of Residual Fragments on the Risk of Repeat Surgery after Flexible Ureteroscopy and Laser Lithotripsy: Single Center Study.

PURPOSE: We analyzed the impact of residual stone fragments seen on abdominal x-ray after ureteroscopy and laser lithotripsy on the risk of repeat surgical intervention. MATERIALS AND METHODS: Our study included 781 patients (802 renal units) who underwent ureteroscopy and laser lithotripsy with abdominal x-ray within 3 months postoperatively and who had at least 1 year of followup. Ureteroscopy and laser lithotripsy were performed using the dusting technique. We analyzed the association between surgical recurrence-free survival and the size of the largest residual fragment. RESULTS: During a median followup of 4.2 years repeat surgery was performed on 161 renal units (20%). Of the repeat interventions 75% were done for symptomatic nephrolithiasis. Postoperative imaging showed residual stone fragments in 42% of cases. In the entire group the risk of repeat surgery was increased in renal units with residual fragments greater than 2 mm. The effect of the size of residual fragments on the risk of surgical recurrence varied by patient body mass index. It was much larger in nonobese subjects, who were at increased risk for repeat surgery with residual fragments of any size. In the obese subgroup only fragments greater than 2 mm increased the risk of surgical recurrence. CONCLUSIONS: The association between the size of residual stone fragments detected by abdominal x-ray after ureteroscopy and laser lithotripsy, and the risk of repeat surgical intervention depends on patient body mass index. Nonobese patients with residual stone fragments of any size are at increased risk for repeat intervention compared to those with a negative abdominal x-ray. The predictive value of abdominal x-ray after ureteroscopy and laser lithotripsy is limited in obese patients.

Association of Patient Age and Gender with Kidney Stone Related Quality of Life.

PURPOSE: Kidney stone formers have lower health related quality of life than nonstone formers. The North American Stone Quality of Life Consortium is a multicenter, longitudinal, prospective study of health related quality of life in patients with kidney stones using the WISQOL (Wisconsin Stone Quality of Life Questionnaire) with data on 2,052 patients from a total of 11 centers. This study is a subanalysis of cross-sectional data looking at the association of age, gender and race on health related quality of life of stone formers. MATERIALS AND METHODS: We performed multivariable analyses of ordinal logistic regression analyses to determine the impact of age, gender and race on health related quality of life, adjusting for other baseline covariates. The proportional odds assumption of ordinal logistic regression was checked. Total score and scores on 4 subdomains (social functioning, emotional functioning, stone related impact and vitality) were included. RESULTS: Median total score for all patients was 80.4. On multivariable analysis older patients had a significantly higher total health related quality of life score than younger patients (per 10-year increase OR 1.25, p <0.0001). Male patients had higher scores than females (OR 1.56, p = 0.0003) and nonCaucasian patients had lower health related quality of life than nonLatino Caucasian patients (OR 0.63, p = 0.0045). CONCLUSIONS: Younger and female patients with kidney stones have lower health related quality of life than older and male patients, respectively. NonCaucasian patients with stones also have lower health related quality of life. The clinical impact of these findings might include future implications for patient counseling, including dietary and medical management of stone disease, and potential changes to the paradigm of the surgical management of stones.

Low Income and Nonwhite Race are Strongly Associated with Worse Quality of Life in Patients with Nephrolithiasis.

PURPOSE: Kidney stones are a source of significant morbidity which have been shown to negatively impact health related quality of life. We sought to understand the association between health related quality of life, socioeconomic status and race among patients with kidney stones. MATERIALS AND METHODS: Patients with stones at a total of 11 stone centers across the United States completed the WISQOL (Wisconsin Stone Quality of Life questionnaire). The patient ZIP Code™ was used to estimate household income. A mixed effects regression model was constructed for analysis with ZIP Code as the random intercept. RESULTS: A total of 2,057 stone formers completed the WISQOL. Lower income was independently associated with significantly lower health related quality of life (ß = 0.372, p = 0.014), as were nonwhite race (ß = -0.299, p = 0.001), unemployed work status (ß = -0.291, p = 0.008), female gender (ß = -0.204, p <0.001), body mass index greater than 40 kg/m2 (ß = -0.380, p <0.001), 5 or more medical comorbidities (ß = -0.354, p = 0.001), severe recurrent stone formation (ß = -0.146, p = 0.045), enrollment at an acute care visit, or a preoperative or postoperative appointment (ß = -0.548, p <0.001) and recent stone symptoms (ß = -0.892, p <0.001). CONCLUSIONS: Lower income, nonwhite race and unemployed work status were independently associated with lower health related quality of life among patients with kidney stones. While clinical characteristics such as body mass and stone disease severity were also associated with health related quality of life, this study shows that socioeconomic factors are similarly important. Further research to understand the specific mechanisms by which socioeconomic status and race impact health may lend insight into methods to optimize clinical treatment of stone formers and patients with other chronic diseases.

Oxalate Content of Enteral Nutrition Formulas.

OBJECTIVES: Patients requiring oral and/or enteral nutrition support, delivered via nasogastric, gastric, or intestinal routes, have a relatively high incidence of calcium oxalate (CaOx) kidney stones. Nutrition formulas are frequently made from corn and/or or soy, both of which contain ample oxalate. Excessive oxalate intake contributes to hyperoxaluria (>45 mg urine oxalate/day) and CaOx stones especially when unopposed by concomitant calcium intake, gastrointestinal malabsorption is present, and/or oxalate degrading gut bacteria are limiting or absent. Our objective was to assess the oxalate content of commonly used commercial enteral nutrition formulas. METHODS: Enteral nutrition formulas were selected from the formulary at our clinical inpatient institution. Multiple samples of each were assessed for oxalate concentration with ion chromatography. RESULTS: Results from 26 formulas revealed highly variable oxalate concentration ranging from 4 to 140 mg oxalate/L of formula. No definitive patterns for different types of formulas (eg, flavored vs unflavored, high protein vs not) were evident. Coefficients of variation for all formulas ranged from 0.68% to 43% (mean ± SD 19% ±â€Š12%; median 18%). CONCLUSIONS: Depending on the formula and amount delivered, patients requiring nutrition support could obtain anywhere from 12 to 150 mg oxalate/day or more and are thus at risk for hyperoxaluria and CaOx stones.

The Effect of Thiazide and Potassium Citrate Use on the Health Related Quality of Life of Patients with Urolithiasis.

PURPOSE: To our knowledge it is unknown whether the benefits of medical management of urolithiasis outweigh the potential side effects of the medications used, including potassium citrate and thiazide diuretics. Therefore, we evaluated the relationship between potassium citrate or thiazides and overall stone related health related quality of life. MATERIALS AND METHODS: Cross-sectional data were obtained on stone forming enrollees in the North American Stone Quality of Life Consortium. We used the WISQOL (Wisconsin Stone Quality of Life) questionnaire to compare health related quality of life between patients treated and not treated with potassium citrate or thiazide type diuretics. Additionally, the likelihood of gastrointestinal complaints was compared between those prescribed and not prescribed potassium citrate. The likelihood of fatigue and sexual complaints was also compared in those prescribed and not prescribed thiazides. RESULTS: Of the 1,511 subjects, including 787 males and 724 females, 279 were on potassium citrate and 238 were on thiazides at study enrollment. Patients prescribed potassium citrate had higher health related quality of life in each domain vs those not prescribed potassium citrate (p <0.001). Patients prescribed thiazides had higher health related quality of life in each domain compared to those not prescribed thiazide (all p <0.01). Those prescribed potassium citrate were less likely than those not prescribed potassium citrate to report nausea, stomach upset or cramps (OR 0.57, p <0.001). Patients prescribed thiazides were less likely than those not prescribed thiazides to report fatigue (OR 0.63, p = 0.004) or reduced sexual interest and/or activity (OR 0.64, p = 0.005). CONCLUSIONS: Among stone formers the use of potassium citrate and thiazides was associated with better health related quality of life across all WISQOL domains without an increased likelihood of gastrointestinal complaints and fatigue or sexual complaints, respectively. These findings may be useful when counseling patients regarding the initiation of potassium citrate or thiazides for medical management of nephrolithiasis.

Updates in the Metabolic Management of Calcium Stones.

PURPOSE OF REVIEW: Urinary risk factors, such as hypercalciuria, hypocitraturia, and hyperoxaluria, either in combination or alone, are associated with calcium stones. Dietary habits as well as underlying medical conditions can influence urinary risk factors. Evaluation of the conglomerate of patients' stone risks provides evidence for individualized medical management, an effective and patient-supported approach to prevention. RECENT FINDINGS: Many patients with stones desire prevention to avoid repeated surgical interventions. Yet, recent practice pattern assessments and health care utilization data show that many patients are rarely referred for metabolic evaluation or management. Innovations in metabolic management over the past decade have improved its effectiveness in reducing risk and preventing calcium stones. Although no new pharmacologic agents for calcium stone prevention have recently become available, there is relatively new thinking about some diet-based approaches. This review will synthesize current evidence to support individualized metabolic management of calcium stones.

Discharge materials provided to patients with kidney stones in the emergency department may be a source of misinformation.

INTRODUCTION: Renal colic is commonly seen in the emergency department (ED), where the focus is on diagnosis and symptom control. Educational materials are sometimes provided upon discharge, however, no standard content has been established. We characterized the educational materials given to patients reporting to EDs in different regions across the U.S. for symptomatic kidney stones, specifically evaluating disease-specific information, symptom management, prevention strategies including dietary recommendations (DRs), and patient follow up plans. MATERIALS AND METHODS: Generic discharge instructions for patients presenting to EDs with renal colic were obtained from community hospitals and academic medical centers between October 2016 and November 2017. Hospitals were called directly. If the same discharge instructions were used by more than one hospital, each was included in our analysis. We assessed the different types of information provided with a focus on stone prevention and DRs by characterizing them into specific nutritional categories. RESULTS: Of 266 hospitals contacted, 79 provided discharge instructions. Of these, 51 (65%) provided some information on diet. While most recommended higher fluid intake, almost 40% endorsed unnecessary fluid restrictions. Recommendations to reduce protein and oxalate intake were common, but erroneous information for both was given. Nearly 1 in 5 EDs recommended lower calcium intake. Less than 30% of EDs mentioned that stones can have different composition or causes. Less than 30% referenced consultation with a registered dietitian nutritionist (RDN) or that dietary approaches to stone prevention are optimally individualized. Only 9 summaries recommended urologic follow up. CONCLUSIONS: Many ED discharge materials contain DRs for stone prevention. These recommendations can be inaccurate and/or inappropriate. Advice on diet and stone prevention is more appropriately addressed in the outpatient setting when more data (stone composition, serum and urine parameters) and expert consultants are available.

Validation and Reliability of the Wisconsin Stone Quality of Life Questionnaire.

PURPOSE: WISQOL (Wisconsin Stone Quality of Life questionnaire) is a disease specific, health related quality of life measure designed for patients who form kidney stones. The purpose of this study was to demonstrate the external and convergent validity of WISQOL and assess its psychometric properties. MATERIALS AND METHODS: At the WISQOL creation site (development sample) and at 8 geographically diverse centers in the United States and Canada (consortium sample) patients with a history of kidney stones were recruited. Item response option variability, correlation patterns and internal consistency were compared between samples. Convergent validity was assessed by patients who completed both WISQOL and SF-36v2® (36-Item Short Form Health Survey, version 2). RESULTS: Results were analyzed in 1,609 patients, including 275 in the development sample and 1,334 in the consortium sample. Response option variability patterns of all items were acceptable. Internal WISQOL consistency was acceptable. Intersample score comparisons revealed few differences. For both samples the domain-total WISQOL score correlations exceeded 0.86. Item level analyses demonstrated suitable variation, allowing for discriminatory scoring. At the time that they completed WISQOL, patients with stones and stone related symptoms scored lowest for health related quality of life. Patients with stones but no symptoms and those with no stones scored higher. The convergent validity substudy confirmed the ability of WISQOL to identify stone specific decrements in health related quality of life that were not identified on SF-36v2. CONCLUSIONS: WISQOL is internally consistent and discriminates among patients with different stone statuses and symptoms. WISQOL is externally valid across the North American population. It may be used for multicenter health related quality of life studies in kidney stone disease.

Prospective evaluation of flexible ureteroscopes with a novel evaluation tool.

INTRODUCTION: Assess the function and handling in the clinical setting of three different types of reusable or disposable ureteroscopes using a novel, comprehensive flexible ureteroscope evaluation tool. MATERIALS AND METHODS: Urologists used a fiberoptic (Olympus URF-P5/P6), digital reusable (Storz Flex Xc), or a new digital disposable ureteroscope (Boston Scientific LithoVue) during ureteroscopic laser lithotripsy. An investigator-designed evaluation tool was used to prospectively assess the performance and handling of the ureteroscopes related to user comfort, maneuverability, efficiency, and various mechanical qualities. After each procedure, surgeons involved in each case who used the ureteroscope completed the written evaluation of the ureteroscope he/she used independently of one another. RESULTS: We reviewed 79 evaluations that were completed after 34 surgical cases; residents and post-graduate MDs were involved in each case. On the characteristics evaluated, significant differences between ureteroscopes were noted. The Storz reusable digital ureteroscope received the highest ratings overall while the new LithoVue disposable ureteroscope generally scored lowest. Our evaluation tool demonstrated good internal consistency, suggesting reliable results. Ureteroscope maneuverability correlated most to overall satisfaction. CONCLUSION: The clinical evaluation of flexible ureteroscopes for stone removal is critical in equipment purchase decision-making and in planning surgical approaches. We created a comprehensive evaluation tool to standardize and quantify the assessment of ureteroscopes used at our institution. Results revealed significant differences between ureteroscopes for several user and performance characteristics and good reliability of the evaluation tool itself.