Hybrid guidewires: Analysis and comparison of the mechanical properties and safety profiles.

INTRODUCTION: Hybrid guidewires are commonly used in urology due to the advantage of an atraumatic hydrophilic tip, which facilitates negotiating tight areas, coupled with an unkinkable nitinol core shaft that is easy to work over due to the Teflon coating. Our aim was to compare the physical and mechanical properties of five commercially available hybrid guidewires to assess their characteristics and functionality. METHODS: In vitro testing was performed on the following straight-tipped 0.035 inch guidewires: Sensor™ (Boston Scientific), Solo™ Plus (Bard), UltraTrack (Olympus), Rio Tracer™ (Rocamed), and Motion™ (Cook). We evaluated characteristics impacting function (tip flexibility, shaft stiffness, lubricity) and safety (perforation force). Measurements included tip flexibility, lubricity, shaft buckling, and force required to perforate a sheet of aluminum foil. RESULTS: The Motion had the highest tip-bending force (p<0.00001). The Rio Tracer had the stiffest shaft (p<0.00001), followed by the Solo Plus and the Motion, which were significantly stiffer than the Sensor and UltraTrack (p<0.00001). The Solo Plus and UltraTrack had the greatest perforation force (p=0.00023), and the Rio Tracer had the lowest perforation force (p=0.016) when compared to the Sensor. There was no significant difference in frictional force between the five guidewires (p=0.1516). CONCLUSIONS: The Solo Plus and UltraTrack required the greatest force to perforate, which conveys a higher safety margin. The RioTracer is the stiffest guidewire, which may be beneficial for instrument insertion with the tradeoff of having a lower perforation force. The clinical significance of higher tip-bending forces (unfavourable) and higher shaft-bending forces (favourable) deserve further investigation.

Urine kidney injury markers do not increase following gastric bypass: a multi-center cross-sectional study.

INTRODUCTION: To determine if markers of kidney injury correlate with urinary oxalate excretion. If so, such biomarkers might be early predictors of oxalate nephropathy. Gastric bypass surgery for obesity is known to be associated with postoperative hyperoxaluria, which can lead to urolithiasis and kidney damage. MATERIALS AND METHODS: Patients were recruited from four large academic centers > 6 months following completion of gastric bypass surgery. Patients provided a spot urine sample for analysis of three markers of kidney injury: 8-iso-Prostaglandin F2 α, N-acetyl- ß -D-Glucosaminidase, and Neutrophil gelatinase-associated lipocalin. Patients also provided 24 hour urine samples for stone risk analysis. RESULTS: A total of 46 study patients provided samples, the average age was 48.4 +/- 11.3. There were 40 women and 6 men. There was no difference in the level of any of the three inflammatory markers between the study group and the reference range generated from healthy non-hyperoxaluric subjects. Neither oxalate excretion nor supersaturation of calcium oxalate correlated with any of the injury markers. There was no difference noted between those with hyperoxaluria (n = 17) and those with normoxaluria (n = 29) with respect to any of the injury markers. CONCLUSIONS: Though hyperoxaluria was common after bypass surgery, markers of kidney injury were not elevated after surgery. No correlation was found between urine oxalate excretion and any of the injury markers.

Mini Versus Standard Percutaneous Nephrolithotomy: The Impact of Sheath Size on Intrarenal Pelvic Pressure and Infectious Complications in a Porcine Model.

OBJECTIVE: To determine how sheath and endoscope size affect intrarenal pelvic pressures and risk of postoperative infectious complications comparing "Mini" vs "Standard" percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: Uropathogenic Escherichia coli were grown and 109 of them were instilled into the porcine renal pelvis through retrograde access for 1 hour. Percutaneous access utilized a 14/16F 20 cm ureteral access sheath for the Mini arm and a 30F sheath for the Standard arm. Nephroscopy was simulated utilizing either an 8/9.8F semirigid ureteroscope or 26F nephroscope for 1 hour while intrarenal pelvic pressure was continuously monitored. Blood and tissue cultures of kidney, liver, and spleen biopsies were plated and incubated and positive cultures were confirmed with polymerase chain reaction. RESULTS: Intrapelvic pressures were higher in the Mini group, 18.76 ± 5.82 mm Hg vs 13.56 ± 5.82 mm Hg (p < 0.0001). Time spent above 30 mm Hg was greater in the Mini arm, 117.0 seconds vs 66.1 seconds (p = 0.0452). All pigs had positive kidney tissue cultures whereas spleen cultures were positive in 100% and 60% of pigs in the Mini and Standard arms, respectively (p = 0.0253); 90% and 30% had positive liver tissue culture in the Mini and Standard arms, respectively (p = 0.0062). Blood cultures were positive in 30% of pigs in the Mini arm compared with none in the Standard arm (p = 0.0603). CONCLUSION: Mini-PCNL was associated with higher intrarenal pressures and higher risk of end organ bacterial seeding in the setting of an infected collecting system. This suggests a higher potential for infectious complications in a clinical setting.

Inflammatory Cytokines in the Papillary Tips and Urine of Nephrolithiasis Patients.

INTRODUCTION: Intrarenal inflammation has been implicated in the pathogenesis of nephrolithiasis, with prior work showing increased urine levels of IL-6, IL-8, and CCL-2 in stone patients. However, no studies have assessed for inflammation in the renal papillae. We sought to characterize novel papillary tip and urinary biomarkers in stone patients. MATERIALS AND METHODS: Ninety-two patients with nephrolithiasis undergoing percutaneous nephrolithotomy were enrolled. Papillary tip biopsies, kidney urine, and bladder urine were collected, as well as voided urine from eight healthy volunteers. Quantitative polymerase chain reaction was performed to measure inflammatory gene expression. RESULTS: Initial 84-gene polymerase chain reaction array revealed significant elevation of several cytokines in stone patients vs controls (fold change 2.3-694). Twenty-four genes were selected for final analysis. In 41 pairs of urine samples, levels of CCL5, CD40, FasL, RIPK2, SELE, TLR3, and IL-15 were significantly elevated in kidney vs bladder urine (p0.0001-0.04). In 23 triplets of samples, expression of these cytokines plus CCL2, CCL7, CCR2, CSF1, CXCL9, and CXCL10, was significantly greater in papillary tips vs urine samples (p0.001-0.05). Cytokine elevation was independent of maximum postoperative heart rate, respiratory rate, temperature, leukocyte count, urinary tract infection in the past year, presence or absence of antibiotics at the time of surgery, and stone composition (all p > 0.05). CONCLUSION: Expression of CCL-2, CCL-5, CCL-7, CCR-2, CD40, CSF1, CXCL-9, CXCL-10, Fas-L, RIPK2, SELE, and TLR-3 is markedly elevated in the papillary tips, kidney urine, and bladder urine of nephrolithiasis patients. Cytokine elevation was independent of signs of systemic inflammation. These findings further support the role of inflammation in nephrolithiasis and imply that the inflammatory process likely begins at the renal papillae. These may represent novel biomarkers of stone disease, which may be useful in basic nephrolithiasis research, disease diagnosis, and prognosis.

American Urological Association Antibiotic Best Practice Statement and Ureteroscopy: Does Antibiotic Stewardship Help?

PURPOSE: To determine compliance with the American Urological Association (AUA) antimicrobial prophylaxis best practice statement and whether the use of postoperative antibiotics is associated with lower rates of postoperative urinary tract infection (UTI) in patients with nephroureterolithiasis and a negative preoperative urine culture undergoing ureteroscopy. MATERIALS AND METHODS: A retrospective review of all adult patients undergoing ureteroscopy from 2013 to 2014 for stone disease with a negative preoperative urine was conducted. Patients who did and did not receive postoperative oral antibiotics beyond 24 hours of surgery were identified. The rates of culture-proven postoperative UTI and unplanned postoperative encounters were determined for both groups. Between-group comparisons were made by using independent t-test and Chi-square analyses. RESULTS: A total of 1068 patients met inclusion criteria and 31.6% were managed in accordance with the AUA best practice statement by not receiving antibiotics beyond 24 hours of surgery. Overall, 33 patients developed a culture-proven UTI within 30 days after surgery, with no difference in UTI rate between patients who did and did not receive home-going antibiotics (2.9% vs 3.6%, respectively; p = 0.5). Rates of unplanned hospital encounters also did not differ between groups (23.7% vs 27.0%, respectively; p = 0.2). On multivariate regression, culture-proven UTI within 1 year before surgery was the only factor associated with postoperative UTI (odds ratio: 10.8, p < 0.0001). CONCLUSIONS: Patients who did and did not receive home-going antibiotics after ureteroscopy demonstrated similar rates of postoperative UTI and unplanned hospital encounters. These results suggest that there is no benefit to extended antibiotics after ureteroscopy. The minority of patients managed in accordance with the AUA best practice statement highlights room for quality improvement.

Can a Simplified 12-Hour Nighttime Urine Collection Predict Urinary Stone Risk?

OBJECTIVE: To determine if there is correlation between nighttime 12-hour and traditional 24-hour urine collection in regard to chemistry values and the supersaturations of calcium oxalate, calcium phosphate, and uric acid for the metabolic evaluation of nephrolithiasis. MATERIALS AND METHODS: Ninety-five patients were prospectively enrolled from 2013 to 2015. Patients >18 years of age who presented to a tertiary stone clinic and who would normally be counseled for 24-hour urine collection were eligible for the study. Participants completed 24-hour urine collections twice, with each divided into 2 separate 12-hour collections. Day-time collection began after the first morning void and continued for 12 hours. The night collection proceeded for the next 12 hours through the first morning void. RESULTS: Forty-nine 24-hour samples from 35 patients met inclusion criteria and were included in the analysis. Overall, there was strong correlation between the night 12-hour and the 24-hour urine collections with R2 ranging from 0.76 for pH to 0.96 for Citrate. In our analysis of variability, the nighttime 12-hour collection differed from the 24-hour collection by 30% in 1-9 patients (2.0%-18.4%) based on individual chemistry value. Diagnosis of underlying metabolic abnormalities was concordant in 92% of patients. CONCLUSION: A 12-hour nighttime collection has strong correlation with 24-hour urine collection. As such, simplifying the metabolic evaluation to a 12-hour overnight collection may be feasible-improving compliance and decreasing patient burden.

Current practice of antibiotic utilization for renal colic in the emergency room

ABSTRACT Introduction Urinalysis (UA) in the emergency setting for patients with nephrolithiasis produces potentially confusing results leading to treatment of presumed urinary tract infections (UTIs). Our objective was to evaluate the use of antibiotics in patients with nephrolithiasis in a large network of emergency departments (EDs). Methods A retrospective analysis of all ED visits associated with an ICD-9 diagnosis of nephrolithiasis and a CT scan between 2010 and 2013 was performed. Urinalysis data, the use of IV and PO antibiotics during the ED visit and at discharge were assessed. The presence of fever, elevated serum WBCs, >5 WBCs per hpf, and/or dip positive nitrites were used as appropriate criteria for antibiotic use. Results Urinalysis data were available for 3,518 (70%) of 5,035 patients with an ED diagnosis of nephrolithiasis and CT imaging. Of these visits, 237 patients had positive nitrites (6.7%) and 864 had >5 WBCs per hpf (24.6%) with 158 (4.5%) having both findings for a total of 943 patients. Intravenous antibiotics were given to 244 patients (25.9%) and oral antibiotics were given to 629 patients (66.7 %) with positive UA findings. Of the 2,440 patients with a negative UA and no leukocytosis or fever, 86 patients (3.5%) received IV antibiotics and 533 patients (21.8%) received PO antibiotics upon discharge. Conclusions Proper treatment of nephrolithiasis in the ED includes the screening and diagnosis of concomitant UTIs. However, correct interpretation of UA studies is vital to the correct implementation of antibiotic therapy. This study suggests that 1/3 of patients were undertreated and 21.8% were over-treated.

Tipless Nitinol Stone Baskets: Comparison of Penetration Force, Radial Dilation Force, Opening Dynamics, and Deflection.

OBJECTIVE: To evaluate 5 commercially available tipless nitinol baskets (2.2F) in 4 performance factors: penetration force, radial dilation force, opening dynamics, and deflection limitation. MATERIALS AND METHODS: The 2.2F Coloplast Dormia No-Tip, 1.5F Sacred Heart Medical Halo, 2.2F Cook NCircle Nitinol Tipless Stone Extractor, 1.9F Bard SkyLite Tipless Nitinol Basket, and 1.9F Boston Scientific Zero Tip Nitinol Stone Retrieval Basket were tested for penetration force (safety metric), radial dilation force (functional metric for ureteral calculi), and opening or closing dynamics. Limitation of deflection (functional metric) was tested by measuring the difference in maximal upward and downward angle of deflection of a ureteroscope with and without a basket in place. RESULTS: The Sacred Heart Medical Halo 1.5F basket had the highest mean force required to perforate the foil at 0.676N ± 0.117 (P < .0001). The Sacred Heart Medical Halo 1.5F basket also had the highest mean radial dilation force at 3.04 g ± 0.15 (P < .0001). The Cook NCircle Nitinol Tipless Stone Extractor 2.2F had the most linear pattern of opening, whereas the Coloplast Dormia No-Tip 2.2F and the Sacred Heart Medical Halo 1.5F exhibited exponential opening dynamics. The Cook NCircle Nitinol Tipless Stone Extractor 2.2F limited scope deflection the most with a decrease in 4° downward and 10° upward. The Sacred Heart Medical Halo 1.5F had the least influence on deflection with a decrease in 3° downward and 5° upward. CONCLUSION: The penetration force, radial dilation force, opening dynamics, and resistance to deflection varied between 5 commonly available tipless nitinol stone baskets. A small diameter 1.5F basket is capable of providing optimal performance while sacrificing linear opening.

Current practice of antibiotic utilization for renal colic in the emergency room.

INTRODUCTION: Urinalysis (UA) in the emergency setting for patients with nephrolithiasis produces potentially confusing results leading to treatment of presumed urinary tract infections (UTIs). Our objective was to evaluate the use of antibiotics in patients with nephrolithiasis in a large network of emergency departments (EDs). METHODS: A retrospective analysis of all ED visits associated with an ICD-9 diagnosis of nephrolithiasis and a CT scan between 2010 and 2013 was performed. Urinalysis data, the use of IV and PO antibiotics during the ED visit and at discharge were assessed. The presence of fever, elevated serum WBCs, >5 WBCs per hpf, and/or dip positive nitrites were used as appropriate criteria for antibiotic use. RESULTS: Urinalysis data were available for 3,518 (70%) of 5,035 patients with an ED diagnosis of nephrolithiasis and CT imaging. Of these visits, 237 patients had positive nitrites (6.7%) and 864 had >5 WBCs per hpf (24.6%) with 158 (4.5%) having both findings for a total of 943 patients. Intravenous antibiotics were given to 244 patients (25.9%) and oral antibiotics were given to 629 patients (66.7 %) with positive UA findings. Of the 2,440 patients with a negative UA and no leukocytosis or fever, 86 patients (3.5%) received IV antibiotics and 533 patients (21.8%) received PO antibiotics upon discharge. CONCLUSIONS: Proper treatment of nephrolithiasis in the ED includes the screening and diagnosis of concomitant UTIs. However, correct interpretation of UA studies is vital to the correct implementation of antibiotic therapy. This study suggests that 1/3 of patients were undertreated and 21.8% were over-treated.

Assessing Transplant Attitudes: Understanding Minority Men's Perspectives on the Multifarious Barriers to Organ Donation.

African Americans comprise 11 % of living organ donors, yet constitute 34 % of the kidney transplant waiting list. There are many barriers to organ donation among minorities that include decreased awareness of transplantation, cultural mistrust of the medical community, financial concerns, and fear of the transplant operation. This study investigates the societal misconceptions and demographic health factors that correlate with minority participation in organ and tissue donation. A 57 question Health and Wellness survey was designed to assess participants' demographic information, medical history, professional background, and opinions regarding organ transplantation. Participants were also asked to complete Quality Metric's Short Form-8 (SF-8) survey to assess physical health, mental health, and quality-of-life. Three hundred twenty-six surveys were administered to minority men. The majority of men were identified as African American, and 55 % were below the age of 40. Though 44 % of participants were willing to donate, only 27 % were registered as organ and tissue donors. Minorities who held misconceptions about organ donation-including the belief that they were too old or unhealthy to donate, for example-had lower general, physical, and mental health scores than those who did not (p = <0.0001). Minorities aware of the shortage for organs or who know a registered donor, an organ recipient, a dialysis patient, or someone on the waiting list were more willing to donate organs. Improving the general, physical, and mental health of minorities, coupled with an active educational outreach program, could result in a greater percentage of minorities registering and willing to be organ and tissue donors.

Clinical Predictors of 30-Day Emergency Department Revisits for Patients with Ureteral Stones.

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.

Preoperative Prediction and Postoperative Surgeon Assessment of Volume Preservation Associated With Partial Nephrectomy: Comparison With Measured Volume Preservation.

OBJECTIVE: To evaluate whether surgeons can predict the percent parenchymal mass that will be preserved by partial nephrectomy (PN) based on preoperative imaging, which could have potential utility for preoperative surgical planning and patient counseling. The proportion of preserved viable parenchyma following PN is the primary determinant of functional recovery. However, direct measurement of parenchymal volume preservation (VP) can be complex and time consuming. MATERIALS AND METHODS: For patients managed with PN at our institution (2007-2014), we randomly selected 45 with a third in each of low, intermediate, or high R.E.N.A.L. complexity groups. All patients had recorded postoperative surgeon assessment of volume preservation (SAVP) and measured VP based on preoperative or postoperative computed tomography. Nine clinical providers predicted VP based solely on review of preoperative imaging while blinded to SAVP and measured VP. Clinical experience of the providers ranged from medical students to experienced urologic surgeons. RESULTS: Median age was 66 years, median tumor size was 4.0 cm, and median R.E.N.A.L. was 8. Median measured VP was 81% (interquartile range of 74-89%). Preoperative prediction of VP correlated poorly with measured VP among the different surgeons (mean correlation coefficient, R = 0.34, range = 0.24-0.40). Surgeon experience provided minimal incremental improvement. Correlation between R.E.N.A.L. and measured VP was also marginal (R = 0.43). In contrast, correlation between postoperative SAVP and measured VP was much more robust (R = 0.75, P <.001). CONCLUSION: Preoperative prediction of VP and R.E.N.A.L. score correlated poorly with measured VP for patients managed with PN. In contrast, postoperative SAVP provided a relatively reliable estimate of VP, and should be considered an acceptable substitute in most clinical circumstances.

Medical Expulsive Therapy is Underused for the Management of Renal Colic in the Emergency Setting.

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.

Flexible ureteroscopy with a ureteral access sheath: when to stent?

OBJECTIVE: To compare intra- and postoperative data of patients who underwent ureterorenoscopy (URS) with an access sheath, with and without postoperative stenting. METHODS: We retrospectively identified patients who underwent flexible URS with a ureteral access sheath between January 2102 and January 2013. Two surgeons performed all cases; one who routinely stents after flexible ureteroscopy and a second who selectively stents. Fifty-one patients who were stented and 51 patients not stented after URS were enrolled in this study. Patients were matched by operative time as a surrogate measure of complexity of the procedure. Intra- and postoperative data were compared. We also analyzed if preoperative stenting or sheath diameter had any effect on postoperative pain score for each group. RESULTS: Patients in the stented group were older (P <.001), had larger ureteral access sheaths (P <.001), and greater stone burden (P <.001). Despite this, the stented group had lower pain scores (4.5 ± 3.2 vs 8.9 ± 3.2; P = .025) and were less likely to seek medical assistance for pain than the unstented patients (26.3% vs 3.9%; P = .007). Patients who were prestented before ureteroscopy had lower pain scores than those who were not prestented in the group that did not receive a postoperative stent (4.2 ± 3.4 vs 6.6 ± 2.8; P = .047). CONCLUSION: Postoperative stenting after flexible URS with a ureteral access sheath seems to decrease postoperative pain. Patients might be selected for no ureteral stent if they were prestented before the procedure, and the URS was uneventful.

Oxalobacter colonization in the morbidly obese and correlation with urinary stone risk.

OBJECTIVE: To establish the baseline preoperative prevalence of Oxalobacter formigenes (OF) colonization in a cohort of obese patients scheduled for Roux-en-Y gastric bypass (RYGB) and determine the effect of OF colonization on urinary oxalate excretion. It has been proposed that loss of OF colonization after RYGB may contribute to the development of hyperoxaluria. METHODS: Adult patients scheduled to undergo RYGB were requested to provide a stool specimen and 24-hour urine collection before surgery. OF colonization status was determined by the calcium precipitation test. The 24-hour urine specimens were analyzed by the Litholink Corporation (Chicago, IL). RESULTS: Of the 51 patients submitting initial stool specimens, only 8 (16%) tested positive for OF, whereas 43 (84%) were negative. Patients colonized with OF were older than uncolonized subjects (52.9±6.8 vs 46.0±10.4 years, P=.03). Urinary oxalate was not significantly different between these groups (P=.14). CONCLUSION: OF colonization is uncommon in morbidly obese patients (16%) before surgery. Because hyperoxaluria develops in more than 50% of patients after RYGB, it is unlikely that loss of OF colonization is the primary cause.

Durability of reusable holmium:YAG laser fibers: a multicenter study.

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.

Hyperoxaluria is a long-term consequence of Roux-en-Y Gastric bypass: a 2-year prospective longitudinal study.

BACKGROUND: Recent studies suggest that patients undergoing Roux-en-Y gastric bypass (RYGB) for morbid obesity are at risk for hyperoxaluria, nephrolithiasis, and oxalate nephropathy. Our objective was to conduct a long-term prospective longitudinal study to establish the incidence, clinical progression, and severity of hyperoxaluria after RYGB. STUDY DESIGN: Patients undergoing RYGB between December 2005 and April 2007 provided 24-hour urine collections for comprehensive stone risk analysis 1 week before and 3 months and 1 and 2 years after surgery. Primary outcomes were changes in 24-hour urinary oxalate excretion and relative supersaturation of calcium oxalate from baseline to 2 years post-RYGB. RESULTS: The cohort consisted of 21 patients, including 5 (24%) men and 16 (76%) women. Mean preoperative age and body mass index (calculated as kg/m(2)) were 48.2 +/- 10.5 years (range 25 to 64 years) and 50.5 +/- 9.1 (range 39.7 to 66.6), respectively. Urinary oxalate excretion increased significantly after RYGB (33 +/- 9 mg/day versus 63 +/- 29 mg/day; p

Durability of the next-generation flexible fiberoptic ureteroscopes: a randomized prospective multi-institutional clinical trial.

OBJECTIVES: To evaluate the durability of 4 next-generation flexible ureteroscopes in a randomized, multi-institutional, prospective study. METHODS: Patients at 3 institutions were randomized to 1 of 4 flexible ureteroscopes: the Wolf Viper, Olympus URF-P5, Gyrus-ACMI DUR-8 Elite (DUR-8E), and Stryker FlexVision U-500. Each center used 1 scope from each manufacturer until it needed major repair (primary endpoint). Intraoperative data included total time of use, number of scope insertions through an access sheath, working time in the lower pole, number of insertions and total time for accessory instrumentation in the working channel, number of laser insertions through the working channel, and total laser energy used. RESULTS: A total of 175 patients were randomized. The DUR-8E experienced early catastrophic failure (< or = 10 cases) at all 3 sites; however, this also occurred at 1 site each for the Stryker and Wolf scopes. The DUR-8E required major repair after the fewest average number of cases (5.3), the lowest average total time of usage (108 minutes), the fewest insertions through an access sheath (20.3), the shortest duration of laser firing (31.3 minutes), and the shortest instrument in the working channel time (224.7 minutes). As such, due to variation in durability within manufacturers, no differences could be demonstrated. Visibility ratings for the Wolf iper were significantly better than the DUR-8E (P = .034) and the Flexvision (P = .038). CONCLUSIONS: The Wolf Viper, Olympus URF-P5, and Stryker Flexvision U-500 flexible ureteroscopes seem comparable with regard to durability. However, larger prospective registry-based studies are needed to document significant differences between them.

Celecoxib in the management of acute renal colic: a randomized controlled clinical trial.

OBJECTIVES: To evaluate the efficacy of celecoxib as an analgesic and medical expulsive agent in acute renal colic. METHODS: A prospective randomized double-blind study was conducted on patients presenting with an obstructing ureteral calculus < 10 mm in largest diameter. Patients were randomized to 400 mg of celecoxib, followed by 200 mg every 12 hours for 10 days, or to placebo. Patients with a solitary kidney, renal insufficiency (CR > 1.8), urinary tract infection, or significant cardiovascular disease were excluded. RESULTS: A total of 57 patients provided consent of which 53 completed the study. Four patients were excluded from the analysis because of stone passage or withdrawal of consent before the first dose of study medication. No significant difference was noted in the spontaneous stone passage rate (celecoxib 55.2%, placebo 54.2%) and between celecoxib and placebo with regard to days to stone passage (7.0 vs 9.0, P = .6) or size of stone passed (3.9 vs 4.6 mm, P = .18). No significant difference was noted in pain analog scores (2.6 vs 3.5, P = .71) or narcotic doses (13.2 vs 13.6, P = .74). Furthermore, a 25% decrease in narcotic use (or 19 mg based on placebo mean) was outside the 80% one-sided confidence interval for the change in mean narcotic use between the 2 groups. Thus, it is unlikely (< 20%) that we missed a clinically significant beneficial effect of celecoxib on narcotic consumption because of sample size. CONCLUSIONS: Celecoxib does not facilitate stone passage or decrease narcotic requirements in patients with acute renal colic.

Alfuzosin to relieve ureteral stent discomfort: a prospective, randomized, placebo controlled study.

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.