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Purpose: High-quality evidence comparing supine to prone percutaneous nephrolithotomy (PCNL) for the treatment of complex stones is lacking. This study aimed to compare the outcomes of supine position (SUP) and prone position (PRO) PCNL. Materials and methods: A noninferior randomized controlled trial was performed according to the CONSORT (Consolidated Standards for Reporting Trials) criteria. The inclusion criteria were patients over 18 years of age with complex stones. SUP was performed in the Barts flank-free modified position. Except for positioning, all the surgical parameters were identical. The primary outcome was the difference in the success rate on the first postoperative day (POD1) between groups. The secondary outcome was the difference in the stone-free rate (SFR) on the 90th postoperative day (final SFR). A noninferiority margin of 15% was used. Demographic, operative, and safety variables were compared between the groups. Statistical significance was set at p <0.05. Results: Overall, 112 patients were randomized and their demographic characteristics were comparable. The success rates on POD1 were similar (SUP: 62.5% vs PRO: 57.1%, p=0.563). The difference observed (-5.4%) was lower than the predefined limit. The final SFRs were also similar (SUP: 55.4% vs PRO: 50.0%, p=0.571). SUP had a shorter operative time (mean±SD 117.9±39.1 minutes vs 147.6±38.8 minutes, p <0.001) and PRO had a higher rate of Clavien ≥3 complications (14.3% vs 3.6%, p=0.045). Conclusions: Positioning during PCNL for complex kidney stones did not impact the success rates; consequently, both positions may be suitable. However, SUP might be associated with a lower high-grade complication rate. [ABSTRACT FROM AUTHOR]

Purpose Single institution studies suggest a benefit of a week of preoperative antibiotics prior to percutaneous nephrolithotomy. These studies are limited by lower quality methodology, such as the inclusion of heterogeneous populations or nonstandard definitions of sepsis. The AUA (American Urological Association) Best Practice Statement recommends less than 24 hours of intravenous antibiotics but to our knowledge no other data exist on the duration or benefit of preoperative antibiotics. Using CONSORT (Consolidated Reporting of Trials) guidelines we sought to perform a rigorous multi-institutional trial to assess preoperative antibiotics in patients in whom percutaneous nephrolithotomy was planned and who were at low risk for infection. Materials and Methods This randomized controlled trial enrolled patients undergoing percutaneous nephrolithotomy who were at low risk, defined as negative preoperative urine cultures and no urinary drain. Of the subjects 43 were randomized to nitrofurantoin 100 mg twice daily for 7 days preoperatively while a control arm of 43 received no oral antibiotics. All subjects received perioperative doses of ampicillin and gentamicin. Prone percutaneous nephrolithotomy was performed by urologists blinded to randomization. The primary outcome was the development of sepsis. Results A total of 86 subjects were enrolled. Preoperative patient characteristics were similar in the treatment and control cohorts with a stone size of 19 and 17 mm, respectively (p = 0.47). Intraoperative characteristics also did not differ. The sepsis rate was not statistically different between the treatment and control groups (12% and 14%, respectively, 95% CI –0.163–0.122, p = 1.0). Other infectious parameters and complications were similar, including intensive care admission, fever, hypotension and leukocytosis. Conclusions Our study demonstrated no advantage to providing 1 week of preoperative oral antibiotics in patients at low risk for infectious complications who undergo percutaneous nephrolithotomy. Perioperative antibiotics according to the AUA Best Practice Statement appear sufficient. [ABSTRACT FROM AUTHOR]

Purpose There is scant evidence in the literature to support dusting vs active basket extraction during ureteroscopy for kidney stones. We prospectively evaluated and followed patients to determine which modality produced a higher stone-free rate with the fewest complications. Materials and Methods Members of the Endourologic Disease Group for Excellence research consortium prospectively enrolled patients with a renal stone burden ranging from 5 to 20 mm in this study. A holmium laser was used and all patients were stented postoperatively. Ureteral access sheaths were used in 100% of basketing cases while sheaths were optional when dusting. The primary study outcome was the stone-free rate at 6 weeks as determined by x-ray and ultrasound. Results A total of 84 and 75 patients were enrolled in the basketing and dusting arms, respectively. Stones in the dusting group were significantly larger (mean ± SD stone area 96.1 ± 65.3 vs 63.3 ± 46.0 mm 2 , p <0.001). The stone-free rate was significantly higher in the basketing group on univariate analysis (74.3% vs 58.2%, p = 0.04) but not on multivariate analysis (1.9 OR, 95% CI 0.9–4.3, p = 0.11). In patients who underwent a basketing procedure operative time was 37.7 minutes longer than in those treated with a dusting procedure (95% CI 23.8–51.7, p <0.001). There was no statistically significant difference in complication rates, hospital readmissions or additional procedures between the groups. Conclusions The stone-free rate was higher for active basket retrieval of fragments at short-term followup on univariate analysis but not on multivariate analysis. There was no difference in postoperative complications or procedures. The 2 techniques should be in the armamentarium of the urologist. [ABSTRACT FROM AUTHOR]

Purpose Preoperative determination of uric acid stones from computerized tomography imaging would be of tremendous clinical use. We sought to design a software algorithm that could apply data from noncontrast computerized tomography to predict the presence of uric acid stones. Materials and Methods Patients with pure uric acid and calcium oxalate stones were identified from our stone registry. Only stones greater than 4 mm which were clearly traceable from initial computerized tomography to final composition were included in analysis. A semiautomated computer algorithm was used to process image data. Average and maximum HU, eccentricity (deviation from a circle) and kurtosis (peakedness vs flatness) were automatically generated. These parameters were examined in several mathematical models to predict the presence of uric acid stones. Results A total of 100 patients, of whom 52 had calcium oxalate and 48 had uric acid stones, were included in the final analysis. Uric acid stones were significantly larger (12.2 vs 9.0 mm, p = 0.03) but calcium oxalate stones had higher mean attenuation (457 vs 315 HU, p = 0.001) and maximum attenuation (918 vs 553 HU, p <0.001). Kurtosis was significantly higher in each axis for calcium oxalate stones (each p <0.001). A composite algorithm using attenuation distribution pattern, average attenuation and stone size had overall 89% sensitivity, 91% specificity, 91% positive predictive value and 89% negative predictive value to predict uric acid stones. Conclusions A combination of stone size, attenuation intensity and attenuation pattern from conventional computerized tomography can distinguish uric acid stones from calcium oxalate stones with high sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Purpose Uric acid nephrolithiasis is associated with an elevated visceral fat area in kidney stone formers. Hepatic steatosis has also been linked to visceral obesity and nephrolithiasis. We evaluated the association of noncontrast computerized tomography based diagnosis of visceral obesity and hepatic steatosis with 24-hour urine parameters and stone composition in kidney stone formers. Materials and Methods A total of 98 kidney stone formers were included in study who had computerized tomography imaging and 24-hour urine studies available. For each patient a single computerized tomography axial area measurement was obtained of the visceral fat area. Hepatic steatosis was diagnosed by comparing the HU of regions from the liver and spleen. Univariate analysis was performed to compare patients with or without an elevated visceral fat area and hepatic steatosis. Multivariate linear and logistic regression was done to assess for variables associated with 24-hour urine parameters and stone composition. Results An elevated visceral fat area was associated with higher 24-hour urine sodium (175 vs 157 mg per day, p <0.036) and lower 24-hour urine pH (5.724 vs 6.478, <0.0001). Urine pH less than 6 (OR 2.52) was associated with hepatic steatosis. Low urine pH less than 6 (OR 11.1, p = 0.004) and stone volume greater than 65 mm 3 (OR 5.12, p = 0.023) were associated with an elevated visceral fat area. Low urine pH less than 6 (OR 5.87) and visceral fat area greater than 48% (OR 5.33) were associated with uric acid stones. Linear regression demonstrated that the percent of visceral fat area was associated with lower 24-hour urine pH (β-coefficient –0.438, p <0.0001). Conclusions Noncontrast computerized tomography based diagnosis of visceral obesity is associated with low urine pH, high urinary sodium and uric acid stone formation. Hepatic steatosis is associated with low urine pH. [ABSTRACT FROM AUTHOR]

Purpose Patients with ureteral stones frequently present to the emergency department for an initial evaluation with pain and/or nausea. However, a subset of these patients subsequently return to the emergency department for additional visits. We sought to identify clinical predictors of emergency department revisits. Materials and Methods We reviewed emergency department visits at our institution with an ICD-9 diagnosis of urolithiasis and an associated computerized tomography scan between 2010 and 2013. Computerized tomography studies were independently reviewed to confirm stone size and location, and degree of hydronephrosis. The primary outcome was a second emergency department visit within 30 days of the initial visit for reasons related to the stone. Patient characteristics and stone parameters at presentation were recorded. Univariable and multivariable analyses were done to identify factors associated with emergency department revisits. Results We reviewed the records of 1,510 patients 18 years old or older who presented to the emergency department with a diagnosis of ureteral stones confirmed by computerized tomography. Of the patients 164 (11%) revisited the emergency department within 30 days. On multivariable analysis the presence of a proximal ureteral stone, age less than 30 years and the need for intravenous narcotics in the emergency department remained independently associated with an emergency department revisit. Conclusions Younger patients, those with proximal stones and those requiring intravenous narcotics for pain control are more likely to return to the emergency department. Consideration should be given for early followup or intervention for these patients to prevent costly emergency department returns. [ABSTRACT FROM AUTHOR]

Purpose This Guideline is intended to provide a clinical framework for the surgical management of patients with kidney and/or ureteral stones. The summary presented herein represents Part II of the two-part series dedicated to Surgical Management of Stones: American Urological Association/Endourological Society Guideline. Please refer to Part I for introductory information and a discussion of pre-operative imaging and special cases. Materials and Methods A systematic review of the literature (search dates 1/1/1985 to 5/31/2015) was conducted to identify peer-reviewed studies relevant to the surgical management of stones. The review yielded an evidence base of 1,911 articles after application of inclusion/exclusion criteria. These publications were used to create the Guideline statements. Evidence-based statements of Strong, Moderate, or Conditional Recommendation were developed based on benefits and risks/burdens to patients. Additional directives are provided as Clinical Principles and Expert Opinions when insufficient evidence existed. Results The Panel identified 12 adult Index Patients to represent the most common cases seen in clinical practice. Three additional Index Patients were also created to describe the more commonly encountered special cases, including pediatric and pregnant patients. With these patients in mind, Guideline statements were developed to aid the clinician in identifying optimal management. Conclusions Proper treatment selection, which is directed by patient- and stone-specific factors, remains the greatest predictor of successful treatment outcomes. This Guideline is intended for use in conjunction with the individual patient’s treatment goals. In all cases, patient preferences and personal goals should be considered when choosing a management strategy. [ABSTRACT FROM AUTHOR]

Purpose This Guideline is intended to provide a clinical framework for the surgical management of patients with kidney and/or ureteral stones. The summary presented herein represents Part I of the two-part series dedicated to Surgical Management of Stones: American Urological Association/Endourological Society Guideline. Please refer to Part II for an in-depth discussion of patients presenting with ureteral or renal stones. Materials and Methods A systematic review of the literature (search dates 1/1/1985 to 5/31/2015) was conducted to identify peer-reviewed studies relevant to the surgical management of stones. The review yielded an evidence base of 1,911 articles after application of inclusion/exclusion criteria. These publications were used to create the Guideline statements. Evidence-based statements of Strong, Moderate, or Conditional Recommendation were developed based on benefits and risks/burdens to patients. Additional directives are provided as Clinical Principles and Expert Opinions when insufficient evidence existed. Results The Panel identified 12 adult Index Patients to represent the most common cases seen in clinical practice. Three additional Index Patients were also created to describe pediatric and pregnant patients with such stones. With these patients in mind, Guideline statements were developed to aid the clinician in identifying optimal management. Conclusions Proper treatment selection, which is directed by patient- and stone-specific factors, remains the greatest predictor of successful treatment outcomes. This Guideline is intended for use in conjunction with the individual patient’s treatment goals. In all cases, patient preferences and personal goals should be considered when choosing a management strategy. [ABSTRACT FROM AUTHOR]

Purpose We performed a prospective comparison of the use of twinkling color Doppler ultrasound and noncontrast computerized tomography in the diagnosis of renal colic in emergency room patients. Materials and Methods A total of 815 consecutive adult patients with suspected renal colic presented to the emergency room and were evaluated immediately with color Doppler ultrasound and noncontrast computerized tomography. The site, side and maximum transverse diameter of the stones were assessed. The patients were followed for 4 to 8 weeks. Results Of 815 patients 723 (88.72%) had ureteral stones, 60 (7.36%) had kidney stones and 32 (3.93%) had pain from extra-urinary causes. Mean patient age was 37.17±11 years. Of the 723 patients with ureteral stones 619 (85.6%) were male and 104 (14.4%) were female. The stones were located on the right side in 340 (47%) patients and on the left side in 383 (53%). Color Doppler ultrasound successfully identified the stones in 702 (97.1%) patients and failed in 21 (2.9%). Noncontrast computerized tomography confirmed stones in 720 (99.6%) patients and was negative in 3 (0.4%). The diagnosis was 166 (23%) upper ureter stones, 63 (8.7%) in the middle and 494 (68.3%) in the lower ureter. The color Doppler ultrasound results were significantly affected by the stone site and maximum transverse diameter (p = 0.03 and 0.007, respectively). Conclusions The initial use of color Doppler ultrasound in the emergency room has led to the diagnosis and characterization of ureteral stones in the majority of patients. Color Doppler ultrasound results were comparable to those of the concomitant use of noncontrast computerized tomography. Therefore, color Doppler ultrasound can replace noncontrast computerized tomography in the emergency room. [ABSTRACT FROM AUTHOR]

Purpose We evaluated the impact of intraoperative irrigation pressures on the risk of systemic inflammatory response after percutaneous nephrolithotomy. Materials and Methods Between January 2014 and March 2015, 90 patients with renal stones planned for percutaneous nephrolithotomy were randomized between low (80 mm Hg) and high (200 mm Hg) irrigation pressure. Patient demographics, perioperative outcomes and systemic inflammatory response incidence rates were compared using the chi-square and Wilcoxon signed rank tests. Results Mean patient age, gender, body mass index and other perioperative outcomes were similar in both arms. High pressure irrigation was associated with a higher risk of systemic inflammatory response syndrome (46%) compared to low pressure irrigation (11%, p=0.0002). On multivariate analysis only high irrigation pressure, paraplegia or neurogenic bladder and nonquinolone perioperative medication were predictive of postoperative systemic inflammatory response syndrome. Conclusions High pressure fluid irrigation fluid increases the risk of postoperative systemic inflammatory response syndrome after percutaneous nephrolithotomy. [ABSTRACT FROM AUTHOR]

Purpose Although the 2007 AUA (American Urological Association) guidelines established it as first line therapy for ureteral stones less than 10 mm, widespread adoption of medical expulsive therapy has been low. We determined the current penetrance of medical expulsive therapy guideline recommendations and the efficacy of medical expulsive therapy in reducing the requirement for urological procedures after emergency department visits for ureteral stones. Materials and Methods In a retrospective analysis of patients seen in the emergency department we included 2,105 emergency department visits associated with an ICD-9 diagnosis of urolithiasis in which computerized tomography abdomen/pelvis scan was performed. Outcomes were reviewed for spontaneous passage or required urological procedure. Results Ureteral stones were found in 48.8% of patients, including 50.0% in whom medical expulsive therapy was prescribed. There was no significant difference between patients who did and did not receive medical expulsive therapy. Within 12 weeks of the initial emergency department visit there was no difference in the rate of urological procedures performed in those who received medical expulsive therapy or in the rate of return to the emergency department. Patients treated with medical expulsive therapy experienced a shorter time to spontaneous expulsion (7.1 vs 12.8 days, p = 0.048). Conclusions Medical expulsive therapy for renal colic in the emergency setting remains underused. Half of the patients who met criteria for medical expulsive therapy in this study did not receive the standard of care. Patients treated with medical expulsive therapy achieved spontaneous passage more quickly but there was no difference in the requirement for a urological procedure. These results highlight the need for personnel at emergency departments to better standardize care for patients with ureteral stones. [ABSTRACT FROM AUTHOR]

Purpose We evaluated the internal and construct validity of an assessment tool for cystoscopic and ureteroscopic cognitive and psychomotor skills at a multi-institutional level. Materials and Methods Subjects included a total of 30 urology residents at Ohio State University, Columbus, Ohio; Penn Presbyterian Medical Center, Philadelphia, Pennsylvania; and Mayo Clinic, Rochester, Minnesota. A single external blinded reviewer evaluated cognitive and psychomotor skills associated with cystoscopic and ureteroscopic surgery using high fidelity bench models. Exercises included navigation, basketing and relocation; holmium laser lithotripsy; and cystoscope assembly. Each resident received a total cognitive score, checklist score and global psychomotor skills score. Construct validity was assessed by calculating correlations between training year and performance scores (both cognitive and psychomotor). Internal validity was confirmed by calculating correlations between test components. Results The median total cognitive score was 91 (IQR 86.25, 97). For psychomotor performance residents had a median total checklist score of 7 (IQR 5, 8) and a median global psychomotor skills score of 21 (IQR 18, 24.5). Construct validity was supported by the positive and statistically significant correlations between training year and total cognitive score (r = 0.66, 95% CI 0.39–0.82, p = 0.01), checklist scores (r = 0.66, 95% CI 0.35–0.84, p = 0.32) and global psychomotor skills score (r = 0.76, 95% CI 0.55–0.88, p = 0.002). The internal validity of OSATS was supported since total cognitive and checklist scores correlated with the global psychomotor skills score. Conclusions In this multi-institutional study we successfully demonstrated the construct and internal validity of an objective assessment of cystoscopic and ureteroscopic cognitive and technical skills, including laser lithotripsy. [ABSTRACT FROM AUTHOR]

Purpose We evaluated the impact of surgical extraction of nonobstructing asymptomatic stones on recurrent urinary tract infections and identified predictors of patients who may be rendered infection-free. Materials and Methods We retrospectively reviewed charts to identify patients with recurrent urinary tract infections who underwent surgical stone extraction and were rendered stone-free. Demographic variables as well as procedure, infectious etiology, stone composition and the systemic inflammatory response syndrome rate were also recorded. Patients were divided into 2 groups. Group 1 had no evidence of recurrent infection following surgery while recurrent infection developed in group 2. Univariate analysis was performed using the Wilcoxon signed rank and Fisher exact tests. Logistic regression was used for multivariate analysis. Results We identified 120 patients with recurrent urinary tract infections and a nonobstructive renal stone. Surgical management included shock wave lithotripsy in 32% of cases, ureteroscopy in 7% and percutaneous nephrolithotomy in 61%. Of the 120 patients 58 (48%) remained infection-free after surgery while 62 (52%) experienced recurrent infection. Factors associated with a higher risk of recurrent infections included type 2 diabetes mellitus (OR 1.73, p = 0.01), hypertension (OR 2.8, p = 0.007) and black ethnicity (OR 13.7, p = 0.009). Escherichia coli infections were more likely to resolve (OR 0.34, p = 0.01). In contrast, Enterococcus infections were more likely to persist (OR 2.5, p = 0.04). On multiple logistic regression analysis only race, hypertension and E. coli infections were significant predictors of infection clearance. Conclusions Of patients with recurrent urinary tract infections and asymptomatic renal calculi 50% may be rendered infection-free following stone extraction. Patients with risk factors for recurrent infections after surgery should be counseled that stone extraction might not eradicate the infection. [ABSTRACT FROM AUTHOR]

Purpose We evaluated which variables impact fragmentation and clearance of lower pole calculi after shock wave lithotripsy. Materials and Methods We prospectively evaluated patients undergoing shock wave lithotripsy for a solitary 5 to 20 mm lower pole kidney stone between June 2012 and August 2014. Patient body mass index and abdominal waist circumference were recorded. One radiologist blinded to shock wave lithotripsy outcomes measured stone size, area and density, stone-to-skin distance, infundibular length, width and height, and infundibulopelvic angle based on baseline noncontrast computerized tomography. Fragmentation, success (defined as residual fragments less than 4 mm in asymptomatic patients) and the stone-free rate were evaluated by noncontrast computerized tomography 12 weeks postoperatively. Univariate and multivariate analysis was performed. Results A total of 100 patients were enrolled in the study. Mean stone size was 9.1 mm. Overall fragmentation, success and stone-free rates were 76%, 54% and 37%, respectively. On logistic regression body mass index (OR 1.27, 95% CI 1.11–1.49, p = 0.004) and stone density (OR 1.0026, 95% CI 1.0008–1.0046, p = 0.005) significantly impacted fragmentation. Stone size (OR 1.24, 95% CI 1.07–1.48, p = 0.039) and stone density (OR 1.0021, 95% CI 1.0007–1.0037, p = 0.012) impacted the success rate while stone size (OR 1.24, 95% CI 1.04–1.50, p = 0.029), stone density (OR 1.0015, 95% CI 1.0001–1.0032, p = 0.046) and infundibular length (OR 1.1035, 95% CI 1.015–1.217, p = 0.015) impacted the stone-free rate. The best outcomes were found in patients with a body mass index of 30 kg/m 2 or less, stones 10 mm or less and 900 HU or less, and an infundibular length of 25 mm or less. The coexistence of significant unfavorable variables led to a stone-free rate of less than 20%. Conclusions Obese patients with higher than 10 mm density stones (greater than 900 HU) in the lower pole of the kidney with an infundibular length of greater than 25 mm should be discouraged from undergoing shock wave lithotripsy. [ABSTRACT FROM AUTHOR]

Purpose Flexible ureteroscopy is rapidly becoming a first line therapy for many patients with renal and ureteral stones. However, current understanding of treatment outcomes in patients with isolated proximal ureteral stones is limited. Therefore, we performed a prospective, multi-institutional study of ureteroscopic management of proximal ureteral stones smaller than 2 cm to better define clinical outcomes associated with this approach. Materials and Methods Adult patients with proximal ureteral calculi smaller than 2 cm were prospectively identified. Patients with concomitant ipsilateral renal calculi or prior ureteral stenting were excluded from study. Flexible ureteroscopy, holmium laser lithotripsy and ureteral stent placement was performed. Ureteral access sheath use, laser settings and other details of perioperative and postoperative management were based on individual surgeon preference. Stone clearance was determined by the results of renal ultrasound and plain x-ray of the kidneys, ureters and bladder 4 to 6 weeks postoperatively. Results Of 71 patients 44 (62%) were male and 27 (38%) were female. Mean age was 48.2 years. ASA ® score was 1 in 12 cases (16%), 2 in 41 (58%), 3 in 16 (23%) and 4 in 2 (3%). Mean body mass index was 31.8 kg/m 2 , mean stone size was 7.4 mm (range 5 to 15) and mean operative time was 60.3 minutes (range 15 to 148). Intraoperative complications occurred in 2 patients (2.8%), including mild ureteral trauma. Postoperative complications developed in 6 patients (8.7%), including urinary tract infection in 3, urinary retention in 2 and flash pulmonary edema in 1. The stone-free rate was 95% and for stones smaller than 1 cm it was 100%. Conclusions Flexible ureteroscopy is associated with excellent clinical outcomes and acceptable morbidity when applied to patients with proximal ureteral stones smaller than 2 cm. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this guideline is to provide a clinical framework for the diagnosis, prevention and follow-up of adult patients with kidney stones based on the best available published literature. Materials and Methods The primary source of evidence for this guideline was the systematic review conducted by the Agency for Healthcare Research and Quality on recurrent nephrolithiasis in adults. To augment and broaden the body of evidence in the AHRQ report, the AUA conducted supplementary searches for articles published from 2007 through 2012 that were systematically reviewed using a methodology developed a priori. In total, these sources yielded 46 studies that were used to form evidence-based guideline statements. In the absence of sufficient evidence, additional statements were developed as Clinical Principles and Expert Opinions. Results Guideline statements were created to inform clinicians regarding the use of a screening evaluation for first-time and recurrent stone formers, the appropriate initiation of a metabolic evaluation in select patients and recommendations for the initiation and follow-up of medication and/or dietary measures in specific patients. Conclusions A variety of medications and dietary measures have been evaluated with greater or less rigor for their efficacy in reducing recurrence rates in stone formers. The guideline statements offered in this document provide a simple, evidence-based approach to identify high-risk or interested stone-forming patients for whom medical and dietary therapy based on metabolic testing and close follow-up is likely to be effective in reducing stone recurrence. [ABSTRACT FROM AUTHOR]

Purpose: Based on studies showing the circadian rhythmicity of testosterone the optimal time of day to draw total testosterone in men has classically been reported as between 8 and 11 a.m. However, further studies demonstrated that the testosterone circadian rhythmicity becomes blunted with age. Materials and Methods: We retrospectively reviewed the charts of 2,569 men who presented with erectile dysfunction for total testosterone and draw times. We compared the men by age group, including less than 40 years and 5-year groupings after age 40 years. Total testosterone was analyzed for variability during the most common draw time hours (7 a.m. to 2 p.m.). Results: Mean total testosterone at 7 to 9 a.m. and 9 a.m. to 2 p.m. clinically and statistically differed only in men younger than 40 vs 40 to 44 years old (mean difference 207 ng/dl, 95% CI 98–315, p = 0.0004 vs 149 ng/dl, 95% CI 36–262, p = 0.01). No other group showed a clinically and statistically significant difference between those periods. Conclusions: Total testosterone in men with erectile dysfunction who are younger than 45 years should be drawn as close to 7 a.m. as possible because a statistically and clinically relevant decrease in testosterone will occur during the course of the day. Men older than 45 years with erectile dysfunction can have total testosterone drawn at any time before 2 p.m. without misleading results. [Copyright &y& Elsevier]

Purpose: We studied the impact of dyslipidemia on 24-hour urinalysis and stone composition. Materials and Methods: We retrospectively identified patients with nephrolithiasis who underwent 24-hour urinalysis and lipid profile evaluation within 3 months. Patients were divided into groups based on total cholesterol, high density lipoprotein, nonhigh density lipoprotein and triglycerides. The groups were compared based on demographic data, diabetes, hypertension and each component of 24-hour urinalysis and stone composition. Multivariate analysis and linear regression were performed to control for potential confounders, including age, gender, body mass index, diabetes and hypertension. Results: A total of 2,442 patients with a mean age of 51.1 years were included in study. On multivariate analysis patients with high total cholesterol had significantly higher urinary potassium and calcium, those with low high density lipoprotein or high triglycerides had significantly higher urinary sodium, oxalate and uric acid with lower pH, and those with high nonhigh density lipoprotein had higher urinary sodium and uric acid. Regarding stone composition, high total cholesterol and triglycerides were significantly associated with a higher uric acid stone rate (p = 0.006 and <0.001, respectively). Linear regression showed a significant association of nonhigh density lipoprotein with higher urinary sodium (p = 0.011) and uric acid (p <0.001) as well as triglycerides and higher uric acid (p = 0.017), and lower urinary pH (p = 0.005). Conclusions: There is a link between dyslipidemia and kidney stone risk that is independent of other components of metabolic syndrome such as diabetes and obesity. Specific alterations in the patient lipid profiles may portend unique aberrations in urine physicochemistry and stone risk. [Copyright &y& Elsevier]

Purpose: We established the most common stone composition, and serum and urinary biochemical features in patients with gout and urolithiasis. Materials and Methods: We retrospectively searched for the records of patients diagnosed with gout among all those in our stone registry. A matched case cohort of stone formers was generated from our registry who had the same age, gender and body mass index. Primary end points were baseline 24-hour urinary metabolic panels and stone composition. Medications were considered. Groups were compared using the Student t and chi-square/Fisher exact tests with significance considered at p <0.05. Results: For stone panel evaluation 181 patients met our inclusion criteria. There was no significant difference in 24-hour uric acid between the nongout and gout cohorts but hyperoxaluria was more common in patients with gout (74% vs 61%, p = 0.009). For stone composition analysis 393 patients were included. The gout cohort had lower calcium oxalate monohydrate (39.4% vs 54.7%), calcium oxalate dihydrate (6.0% vs 11.2%) and calcium phosphate (9.6% vs 14.1%) but higher uric acid (42.7% vs 18.2%, each p <0.001). Pure uric acid stones were more common in patients with gout (52.2% vs 22.3%, p <0.001), while calcium oxalate monohydrate (45.2% vs 68.6%, p <0.001), calcium oxalate dihydrate (0.6% vs 3.5%, p = 0.017) and calcium phosphate (1.6% vs 4.9%, p = 0.033) were more common in nongout cases. Patients with gout who were on allopurinol had fewer pure uric acid stones (30.4% vs 56.4%) and more calcium oxalate monohydrate stones (69.6% vs 40.7%, each p <0.001) than those without medication. Conclusions: Uric acid stones are the most common pure stone composition in patients with gout but 48% have nonuric acid stones. Allopurinol changes the stone composition distribution in patients with gout to a pattern similar to that in stone formers without gout. [ABSTRACT FROM AUTHOR]

Purpose: Idiopathic calcium oxalate kidney stones develop by calcium oxalate crystal deposition on Randall plaque. The mechanisms involved in Randall plaque formation are still unclear. We hypothesized that Randall plaque formation is similar to that of vascular calcification, involving components of extracellular matrix, including membrane bound vesicles and collagen fibers. To verify our hypothesis we critically examined renal papillary tissue from patients with stones. Materials and Methods: We performed 4 mm cold cup biopsy of renal papillae on 15 patients with idiopathic stones undergoing percutaneous nephrolithotomy. Tissue was immediately fixed and processed for analysis by various light and electron microscopic techniques. Results: Spherulitic calcium phosphate crystals, the hallmark of Randall plaque, were seen in all samples examined, including in interstitium and laminated basement membrane of tubular epithelium. Large crystalline deposits were composed of dark elongated strands mixed with spherulites. Strands showed banded patterns similar to collagen. Crystal deposits were surrounded by collagen fibers and membrane bound vesicles. Energy dispersive x-ray microanalysis and electron diffraction identified the crystals as hydroxyapatite. Few kidneys were examined and urinary data were not available on all patients. Conclusions: Results showed that crystals in Randall plaque are associated with collagen and membrane bound vesicles. Collagen fibers appeared calcified and vesicles contained crystals. Crystal deposition in renal papillae may have started with membrane vesicle induced nucleation and grown by the further addition of crystals at the periphery in a collagen framework. [Copyright &y& Elsevier]

Purpose: We evaluated the efficacy of α-blockers to improve ureteral stent related morbidity and quality of life. Materials and Methods: We performed a search of MEDLINE®, Embase™ and The Cochrane Library plus a hand search of conference proceedings from January 2000 to October 2010 to identify randomized, controlled trials comparing treatment for ureteral stent symptoms with α-blockers. Two reviewers independently screened studies and extracted data. Trial methodological quality was assessed by The Cochrane Collaboration quality assessment tool. Placebo randomized, controlled trials with the ureteral stent symptom questionnaire as the outcome were eligible for meta-analysis. Meta-analysis was done using the mean difference to determine the aggregate effect size. Results: A total of 12 randomized, controlled trials including 2 α-blockers in a total of 946 patients were eligible, including 4 (33%) presented only as an abstract at a urological meeting and 4 (33%) eligible for meta-analysis. Meta-analysis using a random effects model showed that α-blockers were associated with a significant decrease in urinary symptoms (MD −6.76, 95% CI −11.52 to −2.00, p = 0.005), a significant decrease in pain (MD −3.55, 95% CI −5.51 to −1.60, p = 0.0004) and significant improvement in general health (MD −1.90, 95% CI −3.05 to −0.75, p = 0.001). However, they were not associated with a benefit in work (MD 2.41, 95% CI −1.62 to 6.44, p = 0.24) or sexual matters (MD 0.20, 95% CI −1.06 to 1.45, p = 0.33). Eight studies were not included in the meta-analysis, of which 7 showed a significant clinical decrease in urinary symptoms and pain. Conclusions: Existing evidence from randomized, controlled trials shows that α-blockers are associated with improvement in ureteral stent symptoms and supports their use in routine clinical practice. [ABSTRACT FROM AUTHOR]

Purpose: We categorized trends in failure of the stone baskets as reported in the United States Food and Drug Administration Manufacturer and User Facility Device Experience database. Materials and Methods: We queried the online database using the code for stone baskets (FFL) from January 1996 to December 2009. Variables extracted were the type of basket, malfunction and treatment, and patient outcome. Results: We identified 556 adverse events related to stone baskets. The device configuration was tipped in 48% of cases, tipless in 36%, forceps in 8% and the Stone Cone™ in 8%. Malfunction type included detachment of a portion of the basket in 49% of cases, breakage without detachment in 39% and inability to withdraw the basket in 12%. Compared to the early period studied (1996 to 2004) there was a 3-fold increase in adverse events from 2005 to 2007 and a 6-fold increase from 2008 to 2009. Of adverse events 79% and 11% were managed by endoscopy and open surgery, respectively. Of the patients 42 experienced serious complications requiring major surgery, including ureteral reconstruction in 7, reimplantation in 4 and nephrectomy in 7. Conclusions: With the increased use of stone baskets in the upper collecting system the number of adverse events has increased. Urologists should remain vigilant to prevent, recognize and manage these events. [ABSTRACT FROM AUTHOR]

Purpose: Single use and reusable variants of holmium:YAG laser fibers are available to treat calculi during ureteroscopic procedures. In this prospective, multicenter study we evaluated a series of reusable holmium:YAG laser optical fibers. We hypothesized that reusable fibers provide a cost advantage over single use variants. Materials and Methods: We prospectively recorded fiber data, including type, size, number of uses, laser pulse energy and frequency, and total energy delivered. All fibers were new and purchased off the shelf by staff at each institution. We performed a cost analysis comparing reusable fibers to single use variants. Results: During 541 procedures a total of 37 holmium:YAG optical laser fibers were used, including 21 Laser Peripherals 270 (Laser Peripherals, Golden Valley, Minnesota), 7 Laser Peripherals 365, 4 Lumenis SlimLine™ 200 and 3 Lumenis SlimLine 365 fibers. After stratifying by core size 365 μm core fibers had significantly more uses than 270 μm core fibers (average 23.5 vs 11.3, p <0.02). By fiber type the mean ± SE number of uses was 12.8 ± 2.44, 3 ± 0.4, 21.3 ± 7.12 and 28.7 ± 6.69 for the Laser Peripheral 270, Lumenis SlimLine 200, Laser Peripherals 365 and Lumenis SlimLine 365, respectively. The total cost savings for reusable fibers vs single use variants was $64,125. Conclusions: Reusable holmium:YAG optical laser fibers are a more cost-effective option than single use variants. Fibers with a 365 μm core provide more uses than smaller 270 μm variants. [ABSTRACT FROM AUTHOR]

Purpose: We compared the results of shock wave lithotripsy with a newer electromagnetic lithotripter to those of an electrohydraulic lithotripter using identical treatment and followup criteria. Materials and Methods: We performed a case matched comparison of 8,565 patients treated from 2003 to 2007 using the Medstone STS™ and the Modulith® SLX machines, matching for stone size, location and patient body mass index. The outcome of interest was treatment success in producing stone-free status. We report treatment characteristics, such as stone site and size, gating and final stone-free rate. Significance was considered at p <0.05. Results: Overall Modulith SLX and Medstone STS stone-free rates were equivalent (61.1% and 64.5%, respectively, p = 0.0664). Matching and logistic regression results showed that differences in the stone-free rate were insignificant for all stones (p >0.7592), lower pole kidney stones (p = 0.9659) and ureteral stones (p = 0.6409). Medstone STS performed better than Modulith SLX only for distal ureteral stones (83.63% vs 66.67%, p = 0.0154). The rate of post-lithotripsy secondary procedures was equivalent (p = 0.2079). The difference was insignificant for harder stones (p = 0.2988). Conclusions: Shock wave lithotripsy is equally effective using Medstone STS and Modulith SLX for different stone sizes and most stone sites. Shock wave lithotripsy is more successful for lower ureteral stones using the Medstone STS. To our knowledge this is the first study comparing these 2 commonly used lithotripters. [Copyright &y& Elsevier]

Purpose: We determined whether stone attenuation can predict stone fragmentation after shock wave lithotripsy in the pediatric population. Previous studies show that preoperative attenuation in HU on noncontrast computerized tomography predicts shock wave lithotripsy success. To our knowledge study of this parameter in the pediatric population has been lacking to date. Materials and Methods: We performed a multi-institutional review of the records of 53 pediatric patients 1 to 18 years old who underwent shock wave lithotripsy for 3.8 to 36.0 mm renal calculi. Stone size, average skin-to-stone distance and attenuation value were determined by bone windows on preoperative noncontrast computerized tomography. Success was defined as radiographically stone-free status at 2 to 12-week followup after a single lithotripsy session without the need for further sessions or ancillary procedures. Results: After lithotripsy 33 patients (62%) were stone-free and 20 had incomplete fragmentation or required additional procedures. Mean ± SD stone attenuation in successfully treated patients vs those with incomplete fragmentation was 710 ± 294 vs 994 ± 379 HU (p = 0.007). Logistical regression analysis revealed that only attenuation in HU was a significant predictor of success. When patients were stratified into 2 groups (less than 1,000 and 1,000 HU or greater), the shock wave lithotripsy success rate was 77% and 33%, respectively (p <0.003). Conclusions: Stone attenuation less than 1,000 HU is a significant predictor of shock wave lithotripsy success in the pediatric population. This finding suggests that attenuation values have a similar predictive value in the pediatric population as that previously reported in the adult population. [Copyright &y& Elsevier]

Purpose: We determined whether age, gender, body mass index, number of stones, stone location or total stone diameter could independently predict stone-free rates after extracorporeal shock wave lithotripsy in children. Materials and Methods: We reviewed 149 patients 3 to 17 years old undergoing shock wave lithotripsy between 2001 and 2008. Cases were retrieved from a regional shock wave lithotripsy database. Variables analyzed included age, gender, body mass index, number of shocks delivered, stone location, number of stones and total stone diameter. Stone-free status on followup imaging at 2 weeks to 3 months was considered a successful outcome. Results: Of 149 patients 32 had multiple stones. After shock wave lithotripsy 106 patients (71%) were stone-free, 12 (8%) required a repeat procedure and 31 (21%) had residual fragments. Number of stones per patient ranged from 1 to 18 (mean ± SD 2.14 ± 2.60). Mean ± SD number of stones was 1.87 ± 2.42 in successfully treated patients and 2.81 ± 2.92 in those with treatment failure (p = 0.065). Total stone diameter ranged from 2 to 90 mm (mean ± SD 14.03 ± 16.68). Mean total stone diameter was 11.1 ± 13.4 mm in successfully treated patients and 21.3 ± 21.4 mm in those with treatment failure (p <0.005). Conclusions: To our knowledge we present the first multi-institutional cohort study in children demonstrating no significant relationship between successful outcome and patient age, gender, body mass index, stone location or number of stones. Only total stone diameter independently predicted shock wave lithotripsy success. [Copyright &y& Elsevier]

Purpose: Ureteral stents are commonly used to facilitate kidney drainage but they may produce significant stent symptoms and morbidity, and require a secondary procedure for removal. Previous biodegradable stents showed bio-incompatibility or inconsistent degradation, requiring extra procedures to remove undegraded stent fragments. We previously reported a first generation biodegradable stent composed of suture-like material that required placement through the lumen of a sheath and degraded by 10 weeks. We now report second and third generation biodegradable stents that degrade more rapidly and can be placed directly over a polytetrafluoroethylene guidewire. Materials and Methods: Two groups of 16 Yucatan pigs each were unilaterally stented endoscopically with a control nondegradable (biostable) stent or a second generation degradable Uriprene® stent. Blood studies, renal ultrasound and excretory urography were done throughout the study to determine renal function, hydronephrosis and stent degradation. Genitourinary organs were harvested at necropsy for pathological analysis. A third generation stent designed to improve degradation time was bilaterally implanted endoscopically into 4 Yorkshire Farm pigs (total of 8 stents), followed by excretory urography weekly to assess degradation and kidney function. Biomaterial parameters were tested. Results: Second generation stents began degrading at 2 weeks and were completely degraded by 10 weeks. All third generation stents were degraded by 4 weeks. Hydronephrosis was considerably less in the Uriprene group than in control biostable stented kidneys. Biostable stented ureters showed an average higher degree of inflammation, uropathy and nephropathy. Physical characteristics indicate that Uriprene stents are significantly more resistant to stent compression and have markedly higher tensile strength and coil strength comparable to that of other commercially available plastic stents. Conclusions: Our study confirms that Uriprene stents are biocompatible and provide good renal drainage. They hold promise for decreasing the need for a secondary procedure and stent related morbidity, such as infection and irritative symptoms. [Copyright &y& Elsevier]

Purpose: Ureteral stents commonly become infected or encrusted. Various coatings have been developed to decrease bacterial adherence. To our knowledge there has been no in vitro testing of coating with heparin to date. We determined the effects of heparin coating on bacterial adherence of common uropathogens and physical stent properties. Materials and Methods: Heparin coated Radiance ureteral stents (Cook) and noncoated Endo-Sof™ control stents were tested against triclosan eluting Triumph® stents and noneluting Polaris™ control stents for adherence of Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, Staphylococcus aureus and Pseudomonas aeruginosa for 7 days. Adherent bacteria were determined and biofilms were visualized using fluorescent dyes. Radial, tensile and coil strength of the Radiance and Polaris stents was compared to determine the effect of heparin coating on physical stent characteristics. Results: Heparin coating did not decrease bacterial adhesion compared to its control. E. coli adhesion was limited by all stents tested. The Polaris stent showed significantly greater resistance to bacterial adherence for Klebsiella, Pseudomonas and Enterococcus than the Endo-Sof and Radiance stents but was more susceptible to S. aureus adherence. The Triumph stent resisted all bacteria except Pseudomonas and Enterococcus. Mature biofilms were observed on all stents with lower viability on the Triumph stent. Radiance stents showed higher tensile and lower compression strength than its control. Conclusions: Heparin coating does not decrease bacterial adherence to ureteral stents. Drug eluting antimicrobials have an inhibitory effect on bacterial adherence and the Polaris stent showed the least bacterial adherence of the nondrug eluting ureteral stents tested. [Copyright &y& Elsevier]

Purpose: We determined the most accurate method of measuring urinary stones on computerized tomography. Materials and Methods: For the in vitro portion of the study 24 calculi, including 12 calcium oxalate monohydrate and 12 uric acid stones, that had been previously collected at our clinic were measured manually with hand calipers as the gold standard measurement. The calculi were then embedded into human kidney-sized potatoes and scanned using 64-slice multidetector computerized tomography. Computerized tomography measurements were performed at 4 window settings, including standard soft tissue windows (window width-320 and window length-50), standard bone windows (window width-1120 and window length-300), 5.13× magnified soft tissue windows and 5.13× magnified bone windows. Maximum stone dimensions were recorded. For the in vivo portion of the study 41 patients with distal ureteral stones who underwent noncontrast computerized tomography and subsequently spontaneously passed the stones were analyzed. All analyzed stones were 100% calcium oxalate monohydrate or mixed, calcium based stones. Stones were prospectively collected at the clinic and the largest diameter was measured with digital calipers as the gold standard. This was compared to computerized tomography measurements using 4.0× magnified soft tissue windows and 4.0× magnified bone windows. Statistical comparisons were performed using Pearson''s correlation and paired t test. Results: In the in vitro portion of the study the most accurate measurements were obtained using 5.13× magnified bone windows with a mean 0.13 mm difference from caliper measurement (p = 0.6). Measurements performed in the soft tissue window with and without magnification, and in the bone window without magnification were significantly different from hand caliper measurements (mean difference 1.2, 1.9 and 1.4 mm, p = 0.003, <0.001 and 0.0002, respectively). When comparing measurement errors between stones of different composition in vitro, the error for calcium oxalate calculi was significantly different from the gold standard for all methods except bone window settings with magnification. For uric acid calculi the measurement error was observed only in standard soft tissue window settings. In vivo 4.0× magnified bone windows was superior to 4.0× magnified soft tissue windows in measurement accuracy. Magnified bone window measurements were not statistically different from digital caliper measurements (mean underestimation vs digital caliper 0.3 mm, p = 0.4), while magnified soft tissue windows were statistically distinct (mean underestimation 1.4 mm, p = 0.001). Conclusions: In this study magnified bone windows were the most accurate method of stone measurements in vitro and in vivo. Therefore, we recommend the routine use of magnified bone windows for computerized tomography measurement of stones. In vitro the measurement error in calcium oxalate stones was greater than that in uric acid stones, suggesting that stone composition may be responsible for measurement inaccuracies. [Copyright &y& Elsevier]

Purpose: We examined the effects of probe rotation and pressure on stone fragmentation in an in vitro percutaneous nephrolithotomy model. Materials and Methods: The study was a fully randomized, factorial experiment with 20 repeat trials performed at each combination of variables, yielding a total of 300 trials per device for ultrasonic tests and 360 for ultrasonic/pneumatic combination tests. Varying masses were placed on the hand piece of each device to create a probe contact pressure of 400, 1,000 or 2,000 gm. The impact of rotation was tested only at 0 or 90 degrees and rotating only at a frequency of 2 Hz. Statistical analysis was performed using R, version 2.6.2. Results: For the Cyberwand® the Tukey HSD test showed that 400 and 1,000 gm probe pressure were significantly more effective than 2,000 gm pressure (p <0.05). The range and frequency of rotation were not statistically significant variables affecting Cyberwand efficiency. For the LithoClast® Ultra® using only the ultrasonic probe significant differences were found among the 3 pressure levels (400, 1,000 and 2,000 gm, respectively, p <0.05). For rotation 90 degrees were significantly more effective than 0 degrees (p <0.05) at a mean ± SD stone mass of 0.168 ± 0.078 and 0.107 ± 0.09 gm, respectively. For the LithoClast Ultra ultrasonic/pneumatic combination 1,000 gm pressure were significantly more effective than 400 or 2,000 gm (p <0.05). The 6 and 12 Hz pneumatic frequencies outperformed 3 Hz but were not significantly different from each other (p <0.05). Conclusions: Differences in probe manipulation impact stone fragmentation efficiency and procedural success. [Copyright &y& Elsevier]

Purpose: We assessed the impact of alfuzosin on ureteral stent discomfort. Materials and Methods: A total of 66 patients scheduled for unilateral retrograde ureteroscopy with stent placement provided consent for the study. Patients were randomized between placebo and the study medication, and investigators and patients were blinded to the randomization scheme. To evaluate pain and urinary symptoms patients were asked to complete the Ureteral Stent Symptom Questionnaire (Stone Management Unit, Southmead Hospital, Westbury-on-Trym, United Kingdom) before ureteroscopy and 3 days after the procedure to minimize the confounding impact of procedural discomfort due to surgery. Patients were also asked to maintain a use log of pain medication each day that the ureteral stent was in place. Procedure outcome and complications were recorded, as were patient study medication use and vital health information before the procedure and at the time of stent removal. Statistical analysis was performed using the Student t, chi-square and Wilcoxon rank sum tests, as appropriate, with p <0.05 considered significant. Results: Of 66 patients who provided consent 55 successfully completed the study. In 3 of the 11 failed cases surgery was not done due to spontaneous stone passage, surgery was performed in 3 but no ureteral stent was placed, 4 were excluded from study after obtaining consent due to exclusion criteria and 1 was voluntarily removed from study after obtaining consent but before surgery. Regarding stent type, procedure complications and baseline questionnaire results there were no significant differences between the placebo and alfuzosin arms. When comparing post-procedure questionnaire results, patients in the alfuzosin arm reported less overall pain in the kidney/back/loin area and less pain in the kidney area while passing urine (p = 0.017 and 0.007, respectively). Men in the alfuzosin arm also reported a lesser incidence of excessive urination (p = 0.040). When comparing changes from baseline questionnaire results, the alfuzosin arm experienced a decrease in kidney pain during sleep (p = 0.017), less frequent use of painkillers to control kidney pain (p = 0.020) and a decrease in how much kidney associated pain interfered with life (p = 0.045). There was no significant difference in the amount of narcotics used per day, as reported in patient medication logs. Conclusions: Alfuzosin improves the patient discomfort associated with ureteral stents by decreasing urinary symptoms and kidney pain but it does not affect the amount of narcotics that patients use while the stent is in place. [Copyright &y& Elsevier]

Purpose: We evaluated the efficacy of alfuzosin as medical expulsive therapy for distal ureteral stone passage. Materials and Methods: A total of 76 patients with a distal ureteral calculus provided consent for the study. Patients were randomized between placebo and study medication, and investigators and patients were blinded to the randomization scheme. Followup was done on a weekly basis and continued until the patient was rendered stone-free. The patient blood pressure, discomfort level, stone position on imaging, number of remaining pills and any adverse events were assessed. Statistical analysis was performed with the Student t test with p <0.05 considered significant. Results: The overall spontaneous stone passage rate was 75%, including 77.1% for placebo and 73.5% for alfuzosin (p = 0.83). Mean ± SD time needed to pass the stone was 8.54 ± 6.99 days for placebo vs 5.19 ± 4.82 days for alfuzosin. (p = 0.003). There was no difference in the size or volume of stones that passed spontaneously between the placebo and alfuzosin arms, as measured on baseline computerized tomography (4.08 ± 1.17 and 3.83 ± 0.95 mm, p = 0.46) and by a digital caliper after stone expulsion (3.86 ± 1.76 and 3.91 ± 1.06 mm, respectively, p = 0.57). When comparing the improvement from the baseline pain score, the alfuzosin arm experienced a greater decrease in pain score in the days after the initial emergency department visit to the date of stone passage (p = 0.0005). Conclusions: Alfuzosin improves the patient discomfort associated with stone passage and decreases the time to distal ureteral stone passage but it does not increase the rate of spontaneous stone passage. [Copyright &y& Elsevier]

Purpose: To our knowledge baseline lithogenic risk factors in the morbidly obese population are currently unknown. Prior studies evaluated known stone formers and correlated risk with increasing body mass index. We describe risk factors for urinary stone formation in a group of unselected morbidly obese patients. Materials and Methods: Patients scheduled for gastric bypass provided a 24-hour urine collection before surgery. Patient demographics, medications and supplement consumption were recorded. A dietary intake diary was converted into daily kcal, Ca, Na and protein consumption. Differences between groups based on gender, history of diabetes or nephrolithiasis, diuretic use and Ca supplementation were evaluated. Correlation of stone risk parameters with body mass index was evaluated. Results: A total of 45 patients provided samples for analysis. Mean ± SD body mass index was 49.5 ± 9.1 kg/m2 and mean age was 47.0 ± 10.5 years. Overall 97.8% of patients had at least 1 lithogenic risk factor identified. Low urinary volume was the most common abnormality, affecting 71.1% of patients. Male patients excreted significantly more Ox (p = 0.0014), Na (p = 0.020), PO4 (p = 0.0083) and SO4 (p = 0.0014) than females. Patients with a history of nephrolithiasis excreted significantly more oxalate (p = 0.018) and had higher relative Na urate supersaturation (p = 0.00093) than nonstone formers. Hydrochlorothiazide use was associated with significantly increased Na urate relative supersaturation (p = 0.0097). Increasing body mass index was inversely associated with Mg (r = −0.38, p = 0.01) and brushite (r = −0.30, p = 0.04). Conclusions: Of our cohort of morbidly obese patients 98% had at least 1 lithogenic risk factor identified on 24-hour urine collection. This study identified a high urinary stone risk in the morbidly obese and suggests possible avenues for dietary and/or pharmacological preventive measures. Future studies will determine how bariatric surgery alters these risk factors. [Copyright &y& Elsevier]

Purpose: To establish the repair patterns of flexible cystoscopes we performed a systematic review of repairs performed at an independent endoscope repair company. Materials and Methods: Repair and cost data for 2000 to 2004 were obtained from an independent endoscope repair company. All cystoscopes underwent a detailed inspection using a preset protocol and the frequency of individual repair descriptions was extracted from a computer database. Results: A total of 1,150 repairs were performed on the Olympus™ CYF (3%), CYF-2 (21%), CYF-3 (56%) and CYF-4 (20%) flexible cystoscopes. Repairs to the distal tip (28% of all repairs) most commonly involved the bending rubber or outer polymer sheath. Repairs to the hand control segment (14% of all repairs) most commonly involved the ocular. Repairs for image (14% of all repairs) and deflection (9%) were most commonly performed on the fiberoptic bundle and wires, respectively. Repairs to the deflection apparatus comprised a significantly greater proportion of total repairs in the early CYF models than in the CYF-4 model (10% to 12% vs 3%, p <0.01, chi-square 10.73). Less than 1% of all cystoscopes needed more than 2 repairs. Conclusions: Olympus cystoscopes require repair every 2 to 3 years and they appear to be durable. The distal deflection tip, specifically the outer bending rubber, is the most common site of flexible cystoscope damage. Although it appears that significant improvements have been made to the deflection apparatus, the number of repairs to other areas has not changed significantly with time. Improvements in form and function of the distal tip, the hand control segment and the fiberoptic bundles may enhance the durability of flexible cystoscopes. [Copyright &y& Elsevier]

Purpose: We performed a randomized, prospective, multi-institutional study evaluating the durability of commercially available flexible ureteroscopes. Materials and Methods: A total of 192 patients were randomized to the use of 7 less than 9Fr flexible ureteroscopes, including the Storz™ 11274AA and Flex-X™, the ACMI™ DUR™-8 and DUR™-8 Elite, Wolf™ models 7330.170 and 7325.172, and the Olympus™ URF-P3. Information about total and lower pole use time, the number and method of ureteroscope insertion, and they type and duration of accessory instrumentation was recorded. Surgeons were asked to rate the visibility and maneuverability of the instrument on a scale of 0—poor to 10—excellent. Results: The indication for ureteroscopy was upper tract calculi in 87% of cases. Of ureteroscope insertions 97% were performed through an access sheath. The average of number of cases before repair ranged from 3.25 for the Wolf™ 7325 to 14.4 for the ACMI™ DUR™-8 Elite. Average ureteroscope operative time was statistically longer for the DUR™-8 Elite (494 minutes) than for the Flex-X™ (p = 0.047), and the Wolf™ 7325 and 7330 (p = 0.001 and 0.001, respectively). Duration of use before repair for the URF-P3 (373 minutes) was statistically longer than for the Wolf™ 7325 and 7330 (p = 0.016 and 0.017, respectively). Minutes of use with an instrument in the working channel were significantly more with the DUR™-8 Elite and the URF-P3 than the Wolf™ 7330 (p = 0.017 and 0.008) and 7325 (p = 0.012 and 0.005, respectively). The ureteroscope that experienced the greatest average duration of lower pole use was the URF-P3, while the shortest was the Wolf™ 7325 (103 vs 20 minutes, p = 0.005). Average minutes of laser use before breakage was significantly longer for the DUR™-8 Elite than for the Wolf™ 7325 (110 vs 21 minutes, p = 0.021) and 7330 (24 minutes, p = 0.025). Conclusions: Currently available less than 9Fr flexible ureteroscopes remain fragile instruments. The DUR™-8 Elite and Olympus™ URF-P3 proved to be the most durable devices. [Copyright &y& Elsevier]

Purpose: Prolonged exposure to microgravity during spaceflight causes metabolic changes that increase the risk of renal stone formation. Studies during the Gemini, Apollo, Skylab and Shuttle missions demonstrated alterations in renal function, fluid homeostasis and bone resorption that result in increased urinary supersaturation of calcium oxalate, brushite, sodium urate and uric acid. Developing countermeasures to increased urinary supersaturation is an important priority as the duration of space missions increases. Materials and Methods: A total of 11 sets of identical twins remained on 6-degree head down, tilt bed rest for 30 days to simulate prolonged microgravity. One twin per pair was randomly selected to exercise while supine in a lower body negative pressure chamber 6 days weekly for 40 minutes, followed by 5 minutes of resting lower body negative pressure at 50 mm Hg. The other twin served as a nonexercise control. Pressure in the exercise lower body negative pressure chamber (52 to 63 mm Hg) was adjusted to produce footward forces equivalent to those for upright running on Earth at 1.0 to 1.2 × body weight. Pre-bed rest urinary stone risk profiles were done elsewhere after 5 days of a standardized diet, consisting of 170 mEq sodium, 1,000 mg calcium, 0.8 gm/kg animal protein and 2,500 kcal, and then throughout the bed rest and recovery phases of the protocol. Results: A significant increase in urinary calcium after just 1 week of bed rest was noted in the nonexercise control group (p = 0.001). However, no such increase was noted in the exercise group. Brushite supersaturation increased significantly from bed rest in each group, although the increase was significantly higher in the nonexercise control group than in the exercise group (p = 0.006). Calcium oxalate supersaturation increased during bed rest in the exercise group (p = 0.004). It trended toward a higher level in the nonexercise control group, although this did not achieve significance (p = 0.055) Mean urine volume ± SD was significantly higher in the nonexercise control group than in the exercise group at bed rest week 2 and at week 3 (2.01 ± 0.21 vs 1.63 0.18 l and 2.03 ± 0.22 vs 1.81 ± 0.20, respectively). Urinary pH was significantly higher in the nonexercise control group than in the exercise group at week 1 and week 3 (6.62 ± 0.7 vs 6.49 ± 0.5 and 6.58 ± 0.6 vs 6.49 ± 0.8, respectively, p = 0.01). Conclusions: Bed rest significantly alters the urinary environment to favor calculous formation. Lower body negative pressure chamber treadmill exercise offers some protection against increases in stone risk during simulated microgravity, particularly with regard to the risks of hypercalciuria and brushite stone formation. The use of lower body negative pressure to augment aerobic exercise in space may decrease the risk of stone formation in astronauts. Adjunct measures, including aggressive hydration and alkalinization therapy, should be considered. [Copyright &y& Elsevier]

Purpose: Quantitative measurements of urinary parameters are valuable clinical tools for predicting the risk of nephrolithiasis. To our knowledge no previous studies have evaluated the heritability of urinary stone risk in identical twins. Because these individuals share identical genetics, the R defined by their phenotypic data are theoretically equal to the entire population H2. Materials and Methods: A total of 12 sets of healthy homozygous twins, including 4 males and 8 females for a total of 24 individuals, with a mean age of 25.9 years (range 21 to 36) volunteered for this study. All subjects provided informed written consent before assessment. Urinary stone risk profiles were done elsewhere on 2 consecutive days after 5 days of a standardized diet (170 mEq Na and 2500 kcal). Linear regression was performed on the data to determine R. Because identical twins were used, R was theoretically an estimate of H2. Results: Certain urinary stone risk markers were highly heritable, including urinary calcium (94%), oxalate (94%), citrate (95%), uric acid (96%) and brushite supersaturation (90%), as determined by genotype (H2 90% or greater). Uric acid supersaturation (58%) and urinary sodium (64%) had low degrees of heritability. Conclusions: H2 is a measure of how much of the total variance in phenotype results from differences in genotype, as opposed to environmental differences. For example, an H2 of 95% for citrate suggests that genetic differences account for 95% of the variation in urinary citrate and environmental differences account for the remaining 5%. Therefore urinary calcium, oxalate and citrate are primarily determined by genotype, while environmental factors, particularly those that impact urine pH and urinary volume, may be increasingly important for determining uric acid supersaturation. [Copyright &y& Elsevier]

ABSTRACT: Purpose: Loss of active deflection with insertion of a holmium laser fiber can significantly decrease the efficacy of intrarenal flexible ureteroscopy. We evaluated the impact of inserting a novel, temperature activated, deflectable laser sheath on active deflection and flow rates. Methods and Materials: Active deflection of 5 flexible ureteroscopes was measured with an empty channel and following separate insertions of 2, 272 μm holmium fibers. Insertion of the same fibers was then repeated through a proprietary, temperature activated, coiling nitinol sheath. Active deflection of the sheath following insertion into the working channel was achieved by a rapid flush of 10 cc hot water (60C) through the irrigation side port. Release of active deflection was obtained by repeating this maneuver with cold water (15C). Degrees of deflection were measured in triplicate. Flow rates were measured at 100 cm H2O pressure. Results: Active deflection with an empty working channel decreased significantly with insertion of the 2 laser fibers (12 to 32 degrees). Insertion of the laser fiber through the nitinol sheath followed by temperature activation of the sheath maximized active deflection beyond baseline measures with the laser fibers by up to 60 degrees. Flow rates in all ureteroscopes decreased significantly with the use of the Powerflex sheath (Optical Integrity, Panama City, Florida) but it remained above 12 ml per minute in all ureteroscopes. Conclusions: A temperature activated, deflectable nitinol sheath facilitates active deflection with a 272 μm holmium laser fiber in the working channel of the flexible ureteroscope, suggesting strong potential for clinical evaluation. [Copyright &y& Elsevier]

Purpose: We compared the efficiency of clearance of a simulated clot from a bladder model using a 6-hole irrigation catheter, a traditional Malecot catheter and a modified Malecot catheter with additional side holes. Materials and Methods: Latex balloons 12 inches in diameter served as the bladder model. They were filled with 300 cc Jell-O® gelatin, which had been partially solidified for 8 hours at 36F. Five manual irrigation/aspiration cycles with a 60 cc catheter tip syringe were performed to remove simulated clot from the bladder models and the amount of clot removed was measured. Five bladder models were used to test the efficiency of clot removal for each 22Fr catheter design, including a standard 22Fr Model 361222 Malecot latex 4-wing catheter (Rusch, High Wycombe, United Kingdom) and a 22Fr Bardex® Model 606118-22 latex 6-hole catheter. Two modified versions of the Malecot catheter design involving 2 and 4 additional holes were also tested to determine the effect of a hybrid 6-hole/Malecot design. Results: The 6-hole catheter was more efficient for clot evacuation than the Malecot catheter (p = 0.014). The modified Malecot catheter with 4 additional holes was more efficient than the original Malecot catheter (p = 0.020). However, it was not significantly better than the 6-hole catheter. After 5 irrigation/aspiration cycles 77.0% of residual clot remained in the bladder with the Malecot catheter compared to 60.4% and 54.0% for the 6-hole and modified 4-hole Malecot catheters, respectively. Conclusions: The 6-hole catheter showed an advantage in clot removal over the Malecot catheter design. The enhanced ability of the 6-hole design to remove simulated clot may be attributable to the larger area covered by the holes at the catheter tip. Further investigation to determine the effect of spacing between the holes and the number of holes on the ability to break apart and remove clot is recommended for a more thorough understanding of differences among catheter models and methods of improvement. [ABSTRACT FROM AUTHOR]