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Nephroureterectomy is currently the criterion-standard treatment for high-grade upper tract urothelial carcinoma (UTUC). Current guidelines and expert opinions propose some exceptions to this approach based on patient characteristics, disease status, and function of the contralateral kidney. We present a rare case of a patient with horseshoe kidney, bilateral large nephrolithiasis, high-grade UTUC in one moiety, and relative parenchymal thinning of the contralateral side. The patient was treated with a percutaneous, minimally invasive, nephron sparing approach. The patient also had intracollecting system instillations of gemcitabine and docetaxel. Minimally invasive percutaneous resection of high-grade UTUC is a safe procedure in select cases. Current guidelines may not apply to all patients; unique scenarios with UTUC may require personalized decision-making and treatment at specialized centers., Competing Interests: No conflict of interest has been declared by the authors., (Copyright © 2022 The Authors. Published by Wolters Kluwer Health, Inc.)

Introduction and Objective: Postoperative infection and sepsis account for the most common complications following percutaneous nephrolithotomy (PCNL), as high as 14% in low-risk patients. Although the American Urological Association (AUA) recommends perioperative antibiotics for 24 hours or less for PCNL, practice patterns vary regarding duration of antibiotic therapy. We aimed to compare the efficacy of 24-hour antibiotic coverage vs short-course protocol of antibiotic prophylaxis for PCNL. Materials and Methods: Low-risk patients with a sterile preoperative urine culture undergoing PCNL were prospectively randomized to antibiotics for up to 24 hours after procedure (24Hr) or continued until external urinary catheters were removed (CR) study groups. Patients were given a first generation cephalosporin, or ciprofloxacin in patients with penicillin allergy. Exclusion criteria included age <18 years, receiving antibiotics immediately before the procedure, history of urosepsis, presence of indwelling catheter >1 week, multistage procedure, immunosuppression, pregnancy, multiple antibiotic allergies, and patients who are breastfeeding. Results: Ninety-eight patients were randomized to either 24Hr ( n  = 49) or CR ( n  = 49). Mean duration of antibiotic administration was 20.6 and 34.0 hours in the 24Hr and CR groups ( p  = 0.04), respectively. Age, comorbidities, stone size, operative time, number of punctures, dilations, and proportion of "tubeless" procedures were similar between groups. There were no differences in febrile episodes, rates of systemic inflammatory response syndrome, bacteremia, or culture-proven postoperative urinary tract infection between the 24Hr and CR groups. Overall complication rates were similar between groups. In a subgroup analysis which excluded "tubeless" patients (24 and 29 patients in 24Hr and CR groups, respectively), no differences were seen in postoperative outcomes. Conclusions: In a randomized, prospective study, we found that a 24-hour protocol for antibiotic prophylaxis is not associated with increased risk of infection-related events compared to giving antibiotics until external catheters are removed in patients with low infectious risk undergoing PCNL. Clinicaltrials.gov: NCT02579161.

Percutaneous nephrolithotomy (PCNL) is the gold-standard treatment for large and complex renal stones. Though associated with higher stone-free rates compared to other minimally invasive stone procedures, this comes at the expense of increased morbidity including postoperative pain and discomfort. We describe our enhanced recovery after surgery (ERAS) protocol for PCNL with emphasis on the use of erector spinae plane blocks to improve patient satisfaction and reduce postoperative opioid use and bother.

Kidney stone cultures can be beneficial in identifying bacteria not detected in urine, yet how stone cultures are performed among endourologists, under what conditions, and by what laboratory methods remain largely unknown. Stone cultures are not addressed by current clinical guidelines. A comprehensive REDCap electronic survey sought responses from directed (n = 20) and listserv elicited (n = 108) endourologists specializing in kidney stone disease. Questions included which clinical scenarios prompt a stone culture order, how results influence post-operative antibiotics, and what microbiology lab protocols exist at each institution with respect to processing and resulting stone cultures. Logistic regression statistical analysis determined what factors were associated with performing stone cultures. Of 128 unique responses, 11% identified as female and the mean years of practicing was 16 (range 1-46). A specific 'stone culture' order was available to only 50% (64/128) of those surveyed, while 32% (41/128) reported culturing stone by placing a urine culture order. The duration of antibiotics given for a positive stone culture varied, with 4-7 days (46%) and 8-14 days (21%) the most reported. More years in practice was associated with fewer stone cultures ordered, while higher annual volume of percutaneous nephrolithotomy was associated with ordering more stone cultures (p < 0.01). Endourologists have differing practice patterns with respect to ordering stone cultures and utilizing the results to guide post-operative antibiotics. With inconsistent microbiology lab stone culture protocols across multiple institutions, more uniform processing is needed for future studies to assess the clinical benefit of stone cultures and direct future guidelines., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction and Objective: As life expectancy continues to rise, the prevalence of frailty is also increasing. The idea of frailty and its effect on the operative patient has been previously studied, but not regularly incorporated into routine practice. We present a review on frailty metrics in the literature, validated assessment methods, and simplified screening tools to better predict and optimize patient outcomes. Methods: An online PubMed search was conducted by three authors (T.A., T.G.R.B., M.M.) for overall frailty, frailty assessment, and preoperative risk assessment. Only English publications were included in the analysis. Full-text analysis was then conducted by all three authors to validate the data. Results: An abundance of literature was found on frailty. Even though some methods are validated as extremely effective for assessing frailty, they may be time-consuming and require a specialist. Various quick screening methods are also presented, many already validated, and should be utilized by urologists more regularly. Conclusions: Multiple studies demonstrate the relationship between frailty and surgical patients' outcome. Many quick, office-based, validated tools to screen for frailty are described, and should be incorporated into our practice in appropriate patients. Future research is now focused on the concept of "prehabilitation" to improve patient frailty status in the preoperative setting, and consequently operative outcomes.

Introduction & Objective: Surgical complications are difficult to predict, despite existing tools. Frailty phenotype has shown promise estimating postoperative risk among the elderly. We evaluate the use of frailty as a predictive tool on patients undergoing percutaneous renal surgery., Methods: Frailty was prospectively analyzed using the Hopkins Frailty Index, consisting of 5 components yielding an additive score: patients categorized not frail, intermediate, or severely frail. Primary outcomes were complications during admission and 30-day complication rate. Secondary outcomes included overall hospital length of stay (LOS) and discharge location., Results: A total of 100 patients recruited, of whom five excluded as they did not need the procedure. A total of 95 patients analyzed; 69, 10, and 16 patients were not frail, intermediate, and severely frail, respectively. There were no differences in blood loss, number of dilations, presence of a staghorn calculus, laterality, or location of dilation. Severely frail patients were likely to be older and have a higher American Society of Anesthesiologists score and Charlson comorbidity index. Patients of intermediate or severe frailty were more likely to exhibit postoperative fevers, bacteremia, sepsis, and require ICU admissions (P < 0.05). Frail patients had a longer LOS (P < 0.001) and tended to require skilled assistance when discharge (p < 0.0001)., Conclusions: Frailty assessment appears useful stratifying those at risk of extended hospitalization, septic complications, and need for assistance following percutaneous renal surgery. Risks of sepsis, bacteremia, and post-operative hemorrhage may be higher in frail individuals. Preoperative assessment of frailty phenotype may give insight into treatment decisions and represent a modifiable marker allowing future trials exploring the concept of "prehabilitation"., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

While percutaneous nephrolithotomy (PCNL) remains the treatment modality of choice for kidney stones larger than 2 cm, infectious complications are most common, ranging from 5% to 32%. We present here a novel technique for potentially improving collecting system sterility during PCNL and initial postoperative outcomes. Retrospective chart analysis data of our irrigation protocol were collected from our first 56 patients between February and July 2019. Traditional prone PCNL was performed in a standard manner using fluoroscopic guidance. Using a ureteral catheter that was placed cystoscopically, a renal pelvis urine culture was taken and subsequently 10 mL of betadine solution was instilled into the collecting system. Gentamicin in normal saline (80 mg/3 L) was utilized as the irrigant fluid for the first 6 L of irrigation. From this cohort, 57% patients were women and mean age was 60 ± 14 years. About 23% of patients were diabetic and 55% were hypertensive. Seventy percent of patients had stone burden >2 cm and no patients had stone burden <1 cm. Fifteen patients had positive urine cultures treated preoperatively, while four patients had contaminated cultures. All patients were treated with our antibiotic irrigation and betadine protocol regardless of preoperative cultures or antibiotics. Mean baseline creatinine level was 0.95 ± 0.41, with a mean change of 0.18 at postoperative day 1. Of the 15 (26%) of 56 patients with a systemic inflammatory response syndrome response (two of following four criteria: white blood cells <4 or >12; heart rate >90; hypothermia <96.8°F or hyperthermia >100.4°F; and respiratory rate >20), only six patients (11%) were febrile and two patients had positive blood cultures (3%). There were no adverse reactions to the betadine or antibiotic irrigation. We present here our initial experience of a new technique for renal pelvis sterilization and its safety and feasibility using intrarenal instillation of betadine and antibiotic irrigation. No Clinical Trial Registration number applicable.

Malignant ureteral obstruction is an unfortunate finding that can be caused by a wide-ranging number of malignancies with a prognosis of limited survival. Given its presentation and progression, it can be refractory to treatment by traditional single polymeric ureteral stents. With a higher failure rate than causes of benign ureteral obstruction, a number of other options are available for initial management, as well as in cases of first-line therapy failure, including tandem stents, metallic stents, percutaneous nephrostomies and extra-anatomic stents. We reviewed the literature and carried out a PubMed search including the following keywords and phrases: "malignant ureteral obstruction," "tandem ureteral stents," "metallic ureteral stents," "resonance stent," "metal mesh ureteral stents" and "extra-anatomic stents." The vast majority of studies were small and retrospective, with a large number of studies related to metallic stents. Given the heterogenous patient population and diversity of practice, it is difficult to truly assess the efficacy of each method. As there are no guidelines or major head-to-head prospective trials involving these techniques, it makes practicing up to the specific provider. However, this article attempts to provide a framework with which the urologist who is presented with malignant ureteral obstruction can plan in order to provide the individualized care on a case-by-case basis. What is clear is that prospective, randomized clinical trials are necessary to help bring evidence-based medicine and guidelines for patients with malignant ureteral obstruction., (© 2020 The Japanese Urological Association.)

Objectives: To assess for usefulness and validity evidence for incorporating the C-Arm Trainer (CAT) simulator into the annual AUA hands on course for training percutaneous nephrolithotomy (PCNL)., Materials and Methods: The course started with a didactic session followed by four stations for training the "bull's eye" technique using the CAT simulator. Each station included a pre-test, 30-min practice on the simulator, and post-test. All participants were assessed using a 4-item checklist. All participants were asked to fill in a qualitative self-assessment questionnaire after the pre- and the post-test, and respond to a course evaluation questionnaire and post-course survey., Results: A total of 38 physicians, who attended the hands on course, voluntarily participated in the study. Only 21.1% had previous practice on PCNL simulators. Compared with the results of the checklist total score and the qualitative self-assessment questionnaire scores after the pre-test, there was significant improvement in the checklist total score (p < 0.001), temporal demands (p = 0.003), situational stress (p = 0.003, and performance (0.003) after the post-test. A total of 14 (36%) participants responded to the course evaluation questionnaire, 50% evaluated the course as excellent, 28.6% as very good, and 21.4% as good. Unfortunately, only five (13%) participants responded to the post-course survey, 4/5 implemented the new competencies and knowledge into their practice, and 3/5 have attempted to obtain fluoroscopic guided PCA without assistance., Conclusion: The CAT simulator was considered useful for training the percutaneous renal access procedure. There was significant improvement in the qualitative and quantitative assessment parameters after the post-test compared with the pre-test.

Introduction: Endoscopic management of upper tract urothelial carcinoma has become more popular over the last few decades as there has been an impetus for renal preservation in these patients. While radical nephroureterectomy has been the gold standard in treatment of this disease, ureteroscopic and percutaneous management has become a viable option for select patients., Methods and Materials: The literature on endoscopic management of upper urinary tract tumors was explored. Different management methods are discussed, both from published literature and experience of the authors of this chapter., Results: We review the indications, details of the procedure, and troubleshooting methods in the endoscopic management of upper tract urothelial carcinoma. Imperative indications as well as controversial indications are discussed. The role and efficacy of adjuvant intrarenal topical agents are examined as well as the protocol for administering these agents. Follow-up protocols are also reviewed., Discussion: In select patients, endoscopic management with ureteroscopy and/or percutaneous resection of upper tract urothelial tumors is appropriate and can preserve renal function while obtaining comparable oncologic control compared with radical surgery.

There are several special situations in which urinary lithiasis presents management challenges to the urologist. An in-depth knowledge of the pathophysiology, unique anatomy, and treatment options is crucial in order to maintain good health in these patients. In this review, we summarize the current literature on the management of the following scenarios: bladder stones, stones in bowel disease, during pregnancy, in association with renal anomalies, with skeletal deformities, in urinary diversions, and in children.

Percutaneous nephrolithotomy has become the preferred treatment modality for patients with large renal calculi. The technique provides excellent stone clearance, but complication rates are higher than those of minimally invasive techniques, such as ureteroscopy and shockwave lithotripsy. Guy's stone score, S.T.O.N.E. nephrolithometry, the CROES nomogram, and S-ReSC are contemporary scoring systems introduced to provide standardized grading of stone complexity and outcomes of percutaneous stone surgery. Guy's stone score is easy to apply and has been validated in multiple studies. The S.T.O.N.E. score is based on factors determined through CT imaging, which is the currently preferred imaging modality for patients with nephrolithiasis. The CROES nomogram was developed from data in a large multicentre database and has high statistical power. Determination of the S-ReSC score relies on stone location only, providing a simple approach to grading disease complexity. Each system has advantages and disadvantages, but several studies suggest that their ability to predict stone-free rate is comparable. The optimal system should have a high predictive ability, should be simple to use and should be widely applicable. Additional studies are required to evaluate patient clinical factors that influence stone complexity and are predictive of outcomes. A future unified scoring system might incorporate the strengths of each currently available system and optimize care of patients with nephrolithiasis.

Over 1%-15% of the population worldwide is affected by nephrolithiasis, which remains the most common and costly disease that urologists manage today. Identification of at-risk individuals remains a theoretical and technological challenge. The search for monogenic causes of stone disease has been largely unfruitful and a technological challenge; however, several candidate genes have been implicated in the development of nephrolithiasis. In this review, we will review current data on the genetic inheritance of stone disease, as well as investigate the evolving role of genetic analysis and counseling in the management of nephrolithiasis.

Objective: Selective angioembolization (SAE) effectively diagnoses and treats iatrogenic vascular complications following percutaneous nephrolithotomy (PCNL)., Methods: We retrospectively reviewed 1329 consecutive PCNLs and identified patients who underwent SAE following PCNL with at least 12-month follow-up. Estimated glomerular filtration rate (eGFR) was calculated for all patients preoperatively, postoperatively and at last follow-up. A 1:2 matched cohort analysis was performed., Results: Twenty-three patients underwent SAE and matched to 46 controls. There was no statistically significant difference in preoperative, postoperative, and follow-up eGFR when comparing patients who underwent SAE and those with an uneventful course., Conclusion: Long-term eGFR is comparable in patients who undergo uncomplicated PCNL and those requiring SAE.

Objective: We compared postoperative outcomes and quality of life (QoL) between patients who received a nephrostomy tube vs a ureteral stent following percutaneous nephrolithotomy (PCNL) in a prospective, double-blind, randomized manner., Materials and Methods: Between September 2015 and March 2016, we randomized 30 patients undergoing PCNL to receive nephrostomy drainage (Group 1: 8F or 10F) or Double-J ureteral stent (Group 2) at conclusion of surgery. Nephrostomy tubes were removed within 48 hours (before discharge) and ureteral stents were removed at least 2 weeks after surgery. Patients' QoL was assessed with the Wisconsin StoneQOL questionnaire preoperatively and then 7 to 10 days and 30 days following surgery. Inclusion criteria included an uncomplicated procedure, normal preoperative renal function, and clinically insignificant residual stone fragments on postoperative imaging. We calculated the preoperative and postoperative QoL score difference between the two groups. We also evaluated perioperative characteristics, inpatient analgesic requirements, length of stay (LOS), and postsurgical complications., Outcome: Patient characteristics between Groups 1 and 2 were comparable with similar age (58.3 vs 54.7, p = 0.534), gender ratio, and stone burden (276.6 mm 2 vs 259 mm 2 , p = 0.84) and composition. There was no significant difference between perioperative outcomes, including stone-free rate (93.3% vs 86.7%), operative times (125.7 minutes vs 115 minutes, p = 0.29), estimated blood loss (103.3 mL vs 100.7 mL, p = 0.9), LOS (3.2 days vs 1.9 days, p = 0.1), and complications (2 in each group). Inpatient analgesic requirements were also the same (both 21.1 mg, p = 1.0). Assessment of QoL using the Wisconsin StoneQOL questionnaire showed significant differences between preoperative and postoperative health-related QoL in 18 of the 28-question instrument at 7 to 10 days. Patients in Group 2 had significantly worse QoL change and a multitude of negative responses on the StoneQOL assessment, not only those commonly associated with stent irritation. Eighty percent of participants in Group 2 also attributed their complaints to having a stent placed. Both groups had similar QoL status at 30 days after surgery., Conclusion: Despite the literature advocating "tubeless" PCNL with ureteral stent placement at conclusion of surgery, our randomized prospective study shows that QoL is significantly worse with stent placement than with temporary nephrostomy drainage in the immediate aftermath following PCNL, using a validated QoL assessment instrument specific for nephrolithiasis.

The aim of this study is to determine the association of estimated glomerular filtration rate (eGFR) with 24-h urine analysis and stone composition. We performed a retrospective review of 1060 stone formers with 24-h urinalysis, of which 499 had stone composition analysis available. Comparisons of baseline patient characteristics and urinary abnormalities across eGFR groups (<60, 60-89.9, ≥90 mL/min/1.73 m(2)) were performed using Fisher's exact test for categorical data and analysis of variance for continuous variables. Analyses of 24-h urinalysis and stone composition across eGFR groups were performed using linear regression with eGFR groups as a continuous variable to evaluate trends. Of the 1060 patients in the study, 595 (56 %) were males. The mean age was 53.8 years. A total of 38 (4 %), 77 (7 %), and 945 (89 %) patients had eGFR <60, 60-89.9, and ≥90 mL/min/1.73 m(2), respectively. Lower eGFR was associated with older age, lower body-mass index, and female gender (all P < 0.05). Lower eGFR was also associated with lower urinary volume, calcium, citrate, uric acid, sodium, magnesium, phosphorus, sulfate, and creatinine on both univariable and multivariable analyses, adjusted for demographics, comorbidities and medication use (all P < 0.05). The prevalence of hypocitraturia and hypomagnesuria was associated with decreased eGFR, while hypercalciuria, hyperoxaluria, hyperuricosuria and hyperphosphaturia were associated with higher eGFR (all P < 0.05). Stone composition was similar across eGFR groups (all P > 0.05). In conclusion, lower eGFR was associated with lower excretion of urinary elements in a routine 24-h urinalysis, but similar stone composition.

Purpose: Activities of daily living provide information about the functional status of an individual and can predict postoperative complications after general and oncological surgery. However, they have rarely been applied to urology. We evaluated whether deficits in activities of daily living could predict complications after percutaneous nephrolithotomy and how this compares with the Charlson comorbidity index and the ASA(®) (American Society of Anesthesiologists(®)) classification., Materials and Methods: We retrospectively reviewed the records of all patients who underwent percutaneous nephrolithotomy between March 2013 and March 2014. Those with complete assessment of activities of daily living were included in analysis. Perioperative outcomes, complications and hospital length of stay were examined according to the degree of deficits in daily living activities., Results: Overall 176 patients underwent a total of 192 percutaneous nephrolithotomies. Deficits in activities of daily living were seen in 16% of patients, including minor in 9% and major in 7%. Complications developed more frequently in those with vs without deficits in daily living activities (53% vs 31%, p = 0.029) and length of stay was longer (2.0 vs 4.5 days, p = 0.005). On multivariate logistic regression activities of daily living were an independent predictor of complications (OR 1.11, p = 0.01) but ASA classification and Charlson comorbidity index were not., Conclusions: Activities of daily living are easily evaluated prior to surgery. They independently predict complications following percutaneous nephrolithotomy better than the Charlson comorbidity index or the ASA classification. Preoperative assessment of daily living activities can help risk stratify patients and may inform treatment decisions., (Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Upper tract urothelial carcinoma (UTUC) is rare and its management presents many challenges. Outside of distal ureterectomy for select cases, management has been primarily radical nephroureterectomy. Endoscopic nephron sparing management (NSM) is recognized to have some role in UTUC treatment; however, it is yet to gain firm footing in the treatment algorithm. In this review, we discuss the benefits of NSM with regards to oncologic outcomes, renal function preservation, and cost savings. Finally, we propose recognition of endoscopic NSM as a first-line treatment in selected patients with low risk disease.

Introduction: The gold standard treatment for upper tract urothelial carcinoma (UTUC) is radical nephroureterectomy (RNU). The role of endoscopic resection is limited to low-risk patients. In this study, we present our 30-year experience in the endoscopic management of UTUC., Methods: In this retrospective study, we identified 141 patients who underwent percutaneous UTUC resection. Demographic and clinical data were collected, including tumor characteristics, bacillus Calmette-Guérin (BCG) and mitomycin use, tumor recurrence, progression to RNU, and overall survival (OS), and compared in univariate and multivariate analyses., Results: Median follow-up was 66 months. Recurrence occurred in 37% of low-grade patients and 63% of high-grade (HG) patients, with a median time to recurrence of 71.4 vs 36.4 months, respectively. Grade was the only predictor of recurrence (HR 2.12, p = 0.018). The latest time to recurrence occurred after 116 months of surveillance. RNU was avoided by 87% of patients. Age, imperative indications for endoscopy, a history of bladder cancer, and tumor stage and grade were predictors of OS; however, in multivariate analysis, grade and stage lost significance. BCG and mitomycin did not protect against recurrence, progression to RNU, or death over resection alone., Conclusion: Percutaneous management of UTUC allows for renal preservation in the majority of patients with resectable disease. Patients with HG tumors are more likely to experience recurrence, but are not at an increased risk of death. Intraluminal BCG and mitomycin continue to have a limited adjuvant role to resection. Recurrence may occur many years following initial resection and therefore prolonged surveillance is advised.

Objective: To analyse our experience with and the outcomes and lessons learned from percutaneous nephrolithotomy (PCNL) in the super obese (body mass index [BMI] ≥50 kg/m(2) )., Patients and Methods: In this institutional review board approved study we retrospectively reviewed our PCNL database between July 2011 and September 2014 and identified all patients with a BMI ≥ 50 kg/m(2) . Patient demographics, peri-operative outcomes and complications were determined. Additionally, we identified a number of special PCNL considerations in the super obese that can maximize safe outcomes., Results: A total of 21 PCNL procedures performed on 17 super obese patients were identified. The mean patient age was 54.8 years, the mean BMI was 57.2 kg/m(2) and the mean stone area was 1 037 mm(2) . Full staghorn stones were observed in six patients and partial staghorns in four patients. The mean operating time was 106 min and the mean haemoglobin decrease was 1.2 g/dL. The overall stone-free rate was 87%. There were four total complications: two Clavien grade II, one Clavien IIIb and one Clavien IVb. We identified several special considerations for safely preforming PCNL in the suber obese, including using extra-long nephroscopes and graspers, using custom-cut extra long access sheaths with suture 'tails' secured to easily retrieve the sheath, choosing the shortest possible access tract, readily employing flexible nephroscopes, placing nephroureteral tubes rather than nephrostomy tubes postoperatively, and meticulous patient positioning and padding., Conclusion: With appropriate peri-operative considerations and planning, PCNL is feasible and safe in the super obese. Stone clearance was similar to that reported in previous PCNL series in the morbidly obese, and is achievable with few complications., (© 2015 The Authors BJU International © 2015 BJU International Published by John Wiley & Sons Ltd.)

Currently, there is no single agreement upon an ideal predictive model that characterizes the complexity of renal stones and predicts surgical outcomes following percutaneous nephrolithotomy (PCNL). New predictive tools have recently emerged to systematically and quantitatively assess kidney stone complexity to predict outcomes following PCNL: the Guy's Stone Score, the CROES nomogram, S.T.O.N.E. nephrolithometry, and S-ReSC score. An ideal scoring system should include variables that both influence surgical planning and are predictive of postoperative outcomes. This review discusses the strengths, weaknesses, and commonalities of each of the above scoring systems. Additionally, we propose future directions for the development and analysis of surgical treatment for stone disease, namely, the importance of assessing radiation exposure and patient quality of life when counseling patients on treatment options.

With the expanding use of chronic antithrombotic medical management for coronary artery disease, surgeons face the growing challenge of balancing the risks of postoperative bleeding against perioperative cardiovascular events. Percutaneous nephrolithotomy (PCNL) carries a risk of bleeding and the need for transfusion at baseline, which is further increased in patients on anticoagulation and antiplatelet therapy. Broad perioperative recommendations for risk stratification and antithrombotic management exist for surgical patients, however, they are less clear in those undergoing PCNL. In this review we appraise available literature, guidelines and opinions and present a consensus statement for antithrombotic management in patients undergoing PCNL.

Purpose: Percutaneous nephrolithotomy is commonly performed with the patient prone. There is concern that the prone position, especially in obese patients, negatively affects ventilation due to the restriction of chest compliance and respiratory mechanics. We analyzed the change in airway resistance between supine and prone positioning of patients undergoing percutaneous nephrolithotomy., Materials and Methods: We retrospectively reviewed the intraoperative respiratory parameters of 101 patients who underwent prone percutaneous nephrolithotomy. Peak inspiratory pressure was assessed with the patient supine, at several time points after being turned prone and at the end of the case. The change in peak inspiratory pressure with time was calculated. Results were stratified based on body mass index and data were compared using the paired t-test and Spearman ρ., Results: Of 101 patients 50 (50%) were obese (body mass index 30 kg/m(2) or greater). Median body mass index was 25.6 kg/m(2) in the nonobese cohort and 38.3 kg/m(2) in the obese cohort. Average peak inspiratory pressure while supine and prone was 18.0 and 18.5 cm H2O in the nonobese cohort, and 25.5 and 26.6 cm H2O, respectively, in the obese cohort. Obese patients had significantly higher peak inspiratory pressure in the supine and the prone positions relative to nonobese patients (p <0.0001). However, there was no change in peak inspiratory pressure from the supine to the prone position in either cohort., Conclusions: Obese patients have higher baseline peak inspiratory pressure regardless of position. However, prone positioning does not impact peak inspiratory pressure in either cohort. It remains a safe and viable option., (Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Objective: To specifically report perioperative characteristics and outcomes in patients 80 years and older undergoing percutaneous nephrolithotomy (PCNL). PCNL has been established as feasible in the elderly; however, to our knowledge no one has specifically reported feasibility in patients 80 years and older., Methods: We retrospectively reviewed perioperative data of octogenarians who underwent PCNL at a high stone volume single institution, and matched them to patients <65 years of age by stone burden and sex. Patient demographics, perioperative outcomes and postoperative complications were compared., Results: Thirty-three octogenarians (mean age 83.6 years) with 36 renal units were matched to 67 controls (mean age 48.6 years) with 72 renal units. Octogenarians had a higher mean American Society of Anesthesiologists (ASA) score, more comorbidities, and worse renal function. There were no differences in operative characteristics, length of hospital stay or stone free rates. Of the patients with preoperative urinary decompression (ureteral stent or nephrostomy tube) prior to PCNL, the elderly were more likely to have a history of urosepsis. Octogenarians did not experience more minor Clavien (I - II) or major Clavien (IIIa - IVb) complications., Conclusion: Octogenarians who undergo PCNL were more likely to have cardiovascular comorbidities and a prior history of sepsis. Despite these risk factors, in appropriately selected patients PCNL can be safely and successfully performed in octogenarians without increased perioperative complications relative to a younger cohort.

Extrinsic malignant compression of the ureter is not uncommon, often refractory to decompression with conventional polymeric ureteral stents, and frequently associated with limited survival. Alternative options for decompression include tandem ureteral stents, metallic stents and metal-mesh stents, though the preferred method remains controversial. We reviewed and updated our outcomes with tandem ureteral stents for malignant ureteral obstruction, and carried out a PubMed search using the terms "malignant ureteral obstruction," "tandem ureteral stents," "ipsilateral ureteral stents," "metal ureteral stent," "resonance stent," "silhouette stent" and "metal mesh stent." A comprehensive review of the literature and summary of outcomes is provided. The majority of studies encountered were retrospective with small sample sizes. The evidence is most robust for metal stents, whereas only limited data exists for tandem or metal-mesh stents. Metal and metal-mesh stents are considerably more expensive than tandem stenting, but the potential for less frequent stent exchanges makes them possibly cost-effective over time. Urinary tract infections have been associated with all stent types. A wide range of failure rates has been published for all types of stents, limiting direct comparison. Metal and metal-mesh stents show a high incidence of stent colic, migration and encrustation, whereas tandem stents appear to produce symptoms equivalent to single stents. Comparison is difficult given the limited evidence and heterogeneity of patients with malignant ureteral obstruction. It is clear that prospective, randomized studies are necessary to effectively scrutinize conventional, tandem, metallic ureteral and metal-mesh stents for their use in malignant ureteral obstruction., (© 2015 The Japanese Urological Association.)

Objectives: To examine the differences in 24-h urine composition between nephrolithiasis patients with and without diabetes mellitus (DM) in a large cohort of stone-formers and to examine differences in stone composition between patients with and without DM., Patients and Methods: A retrospective review of 1117 patients with nephrolithiasis and a 24-h urine analysis was completed. Univariable analysis of 24-h urine profiles and multivariable linear regression models were performed, comparing patients with and without DM. A subanalysis of patients with stone analysis data available was performed, comparing the stone composition of patients with and without DM., Results: Of the 1117 patients who comprised the study population, 181 (16%) had DM and 936 (84%) did not have DM at the time of urine analysis. Univariable analysis showed significantly higher total urine volume, citrate, uric acid (UA), sodium, potassium, sulphate, oxalate, chloride, and supersaturation (SS) of UA in individuals with DM (all P < 0.05). However, patients with DM had significantly lower SS of calcium phosphate and pH (all P < 0.05). Multivariable analysis showed that patients with DM had significantly lower urinary pH and SS of calcium phosphate, but significantly greater citrate, UA, sulphate, oxalate, chloride, SSUA, SS of calcium oxalate, and volume than patients without DM (all P < 0.05). Patients with DM had a significantly greater proportion of UA in their stones than patients without DM (50.2% vs 13.5%, P < 0.001)., Conclusions: DM was associated with multiple differences on 24-h urine analysis compared with those without DM, including significantly higher UA and oxalate, and lower pH. Control of urinary UA and pH, as well as limiting intake of dietary oxalate may reduce stone formation in patients with DM., (© 2014 The Authors. BJU International © 2014 BJU International.)

Recently, several scoring systems have been proposed to predict outcomes of percutaneous nephrolithotomy, objectively and quantitatively assessing kidney calculi complexity using cross-sectional imaging. These scoring systems are promising new tools that can guide surgical decision making, predict surgical outcomes, counsel patients undergoing stone surgery, and improve standardized academic reporting in percutaneous kidney stone surgery. In this article, we review features of each of these systems, their similarities and differences, and their applicability in clinical practice and relevance in academic reporting.

Objective: To examine the differences in 24-hour urine parameters and stone composition between patients with and without systemic hypertension (HTN) in a large cohort of stone formers., Materials and Methods: We performed a retrospective review over a 10-year period of patients with stone, who had completed a 24-hour urinalysis (Litholink) and for whom demographic information was available, including the presence of HTN. Univariate and multivariate analyses were performed, comparing the 24-hour urinalysis profiles of patients with HTN with that of normotensive patients., Results: Of the 1115 patients eligible for inclusion, 442 patients (40%) had HTN and 673 (60%) did not. Patients with HTN were significantly older, had a higher body mass index, and had a greater number of comorbid conditions than normotensive patients. Univariate analysis revealed significantly lower urine pH, calcium, supersaturation (SS) of calcium oxalate (CaOx) and SS calcium phosphate (all P <.05) in patients with HTN. Multivariate analysis showed significantly lower calcium, citrate, and SS CaOx in patients with HTN (all P <.05)., Conclusion: Our results demonstrate lower levels of calcium and SS CaOx on univariate and multivariate analysis, as well as lower levels of citrate on multivariate analysis in patients with HTN. These results suggest that lower levels of citrate may contribute to stone formation to a greater degree in patients with HTN than abnormalities in calcium metabolism., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background and Purpose: Urology practices frequently encounter individuals who experience various degrees of pain/discomfort after ureteral stent removal. These symptoms have been previously proved to greatly affect functionality, convalescence time, quality of life, and healthcare costs. The etiology is unclear, but the condition is often self-limiting. We counsel individuals on their risk of having post-ureteral stent removal pain based on anecdotal data. We sought to evaluate the incidence of post-ureteral stent removal pain and attempt to find the probable cause., Patients and Methods: All individuals who had a ureteral stent placed and subsequently removed for various etiologies (between January 2012 and May 2013) were evaluated by filling a survey conducted by a member of the healthcare team 1 to 3 weeks after ureteral stent removal. Univariate and multivariate analysis were used to assess correlation between demographics, operative procedures, convalescent time, and post-ureteral stent removal symptoms. All statistical analyses were performed using SAS(®) software, and a P value of less than 0.05 was considered to indicate statistical significance., Results: Of the 104 individuals in the final cohort, 64% had symptoms after stent removal (pain, hematuria, frequency, urgency, or fever), and among those with symptoms, 60% experienced pain/discomfort. On univariate analysis, stone basketing and indwelling stent discomfort correlated positively with pain after stent removal. On the other hand, the use of anticholinergics and a longer indwelling stent duration were associated with less pain after stent removal. On multivariate analysis, correlation with procedures involving basket extraction and indwelling stent discomfort maintained significance., Conclusion: Our series suggests that two of three individuals who undergo ureteral stent removal experience symptoms thereafter. Individuals undergoing stone basket extraction and those who experienced stent discomfort were more likely to have pain after stent removal. Anticholinergic use and stents indwelling for a longer time were associated with less pain after stent removal.

Introduction: To determine the association of the basic metabolic panel with stone type., Methods: The present study was a retrospective review of 492 stone formers with both stone composition analysis and basic metabolic panel available. Analysis of a basic metabolic panel across stone types was carried out using Fisher's exact test and analysis of variance. Multinomial logistic regression was used to predict stone type based on a basic metabolic panel., Results: A total of 272 (55%) patients had predominantly calcium oxalate stones, 100 (21%) had uric acid stones, 93 (19%) had calcium phosphate stones, 16 (3%) had mixed stones and 11 (2%) had other types of stones. Uric acid stone formers had the highest serum glucose, blood urea nitrogen and creatinine levels. Calcium oxalate stone formers had the highest serum sodium. No significant differences in mean serum calcium levels across different stone types were identified. The predicted risk of uric acid stone over the other stone types increased with an increase in serum glucose and decreased with an increase in carbon dioxide levels. The predicted risk of calcium oxalate stones increased with an increase in serum sodium and chloride levels. The predicted risk of calcium phosphate and oxalate stones over the other stone types increased with an increase in serum calcium levels. The overall accuracy of the basic metabolic panel alone to predict stone type was 59%., Conclusion: A basic metabolic panel alone or in combination with 24-h urinalysis and demographics does not accurately predict stone type. However, it can be used in combination with other variables to predict stone composition., (© 2014 The Japanese Urological Association.)

Treatment of large renal stones has changed considerably in recent years. The increasing prevalence of nephrolithiasis has mandated that urologists perform more surgeries for large renal calculi than before, and this has been met with improvements in percutaneous stone surgery. In this review paper, we examine recent developments in percutaneous stone surgery, including advances in diagnosis and preoperative planning, renal access, patient position, tract dilation, nephroscopes, lithotripsy, exit strategies, and post-operative antibiotic prophylaxis.

Purpose: Contemporary predictive tools for percutaneous nephrolithotomy outcomes include the Guy stone score, S.T.O.N.E. nephrolithometry and the CROES nephrolithometric nomogram. We compared each scoring system in the same cohort to determine which was most predictive of surgical outcomes., Methods: We retrospectively reviewed the records of patients who underwent percutaneous nephrolithotomy between 2009 and 2012 at a total of 3 academic institutions. We calculated the Guy stone score, the S.T.O.N.E. nephrolithometry score and the CROES nephrolithometric nomogram score based on preoperative computerized tomography images. A single observer at each institution reviewed all images and assigned scores. Univariate and multivariate analysis was done to determine the most predictive scoring system., Results: We enrolled 246 patients in study. In stone-free patients vs those with residual stones the mean Guy score was 2.2 vs 2.7, the mean S.T.O.N.E. score was 8.3 vs 9.5 and the mean CROES nomogram score was 222 vs 187 (each p <0.001). Logistic regression revealed that the Guy, S.T.O.N.E. nephrolithometry and CROES nomogram scores were significantly associated with stone-free status (p = 0.02, 0.004 and <0.001, respectively). The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss (p <0.0001 and 0.03) and length of stay (p = 0.03 and 0.009, respectively). The CROES nomogram did not predict estimated blood loss or length of stay., Conclusions: All scoring systems and the stone burden equally predicted stone-free status. The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss and length of stay. A single scoring system should be adopted to unify reporting., (Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Introduction: Aspirin, as an inhibitor of platelets, is traditionally discontinued prior to percutaneous nephrolithotomy (PCNL) given the concern for increased surgical hemorrhage. However, this practice is based on expert opinion only, and mounting evidence suggests holding aspirin perioperatively can be more harmful than once thought. We sought to compared PCNL outcomes and complications in patients continuing aspirin to those stopping aspirin perioperatively., Methods: A retrospective review was performed of 321 consecutive PCNLs done between July 2012 and March 2014. Patients were separated into two groups. The on-aspirin group consisted of patients continuing aspirin throughout the perioperative period. The off-aspirin group had aspirin held temporarily pre- and postoperatively. Surgical outcomes and complications were compared between groups., Results: Of the 321 PCNLs, 60 (18.7%) occurred in patients chronically taking aspirin. The on-aspirin group included 17 PCNLs (5.2%), while the off-aspirin group included 43 PCNLs (13.4%). There were no differences between groups in terms of operative time (77 minutes vs 74 minutes, p=0.212), hemoglobin change (p=0.522), stone size (21 mm vs 22 mm, p=1.0), stone-free rate (p=0.314), median length of hospitalization (p=0.642), transfusion rate (p=0.703), or total complications (p=1.0). No patient experienced a thromboembolic event., Conclusions: PCNL is safe in patients continuing aspirin perioperatively and does not result in more blood transfusions, angioembolization procedures, or complications. Patients with large stone burdens who are at high risk for thromboembolic events appear to be able to safely undergo PCNL without discontinuing aspirin.

Objective: To determine the feasibility and safety of performing percutaneous nephrolithotomy (PCNL) in high-cardiovascular risk patients remaining on aspirin therapy., Methods: We retrospectively reviewed all PCNLs performed by 3 fellowship-trained endourologists at a single institution between July 2012 and January 2014. All patients remaining on aspirin for imperative indications through the day of surgery were evaluated for surgical outcomes and thromboembolic events., Results: Of 281 PCNL procedures performed during the study period, 16 (5.7%) were performed in 14 patients taking aspirin, uninterrupted, through surgery. Mean surgery time was 66 minutes, mean estimated blood loss was 161 mL, and mean length of hospital stay was 2.8 days. All patients were stone free. There were no intraoperative complications. A total of 5 patients experienced a postoperative complication (n = 4, Clavien grade II; n = 1, Clavien grade IIIa). No patient experienced a perioperative thromboembolic or cardiac event. Three patients required a blood transfusion postoperatively, and none experienced delayed renal bleeding., Conclusion: PCNL can be performed safely and effectively in high-cardiovascular risk patients continuing aspirin perioperatively. Compared with the potential sequelae of a thromboembolic or cardiac event, PCNL is associated with an acceptably low transfusion rate, and should be considered a viable treatment option for large renal stones in this population., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Purpose: To evaluate the perception of urologists who have participated in live case demonstrations (LCDs) regarding safety, educational value/benefits, and ethics., Methods: A 19-question anonymous survey was sent to urologists who performed and/or moderated LCDs at the World Congress of Endourology meetings from 2008 to 2012. E-survey was distributed via e-mail, and automatic reminders were sent 2 weeks after original distribution if no response was obtained., Results: Eighty-one percent (92/113) of the urologists responded to the survey of whom 75% practice full time in an academic setting. Only 48.0% were fellowship trained, however. More than 60% had performed more than five LCDs at their home and/or away institutions. Performing LCD at an away institution was associated with a higher level of anxiety when compared with performing LCDs at a home institution (79.8% vs 34.6%; P<0.01). Respondents considered film equipment and crew; audience and moderator discussions; unfamiliar team, instruments and tools; language barrier; and having to narrate the procedure, as distractors. Seventy-nine percent considered LCD as an ethical practice, and 90.5% regarded LCDs as a "beneficial" and a "great way" to educate. Similarly, considering the various factors and conditions associated with LCDs, 95% would agree to participate in another LCD., Conclusion: LCDs are perceived to be an effective mode of education by performers and moderators of LCDs. Standard guidelines and policies are needed, however, for the selection of patient, surgeon and team, equipment, and facility. Studies are needed to evaluate the impact of this education process.

Objective: To compare the metabolic profile of patients who form mixed calcium oxalate (CaOx)/uric acid (UA) stones to those of pure CaOx and pure UA stone formers., Methods: We performed a retrospective review of 232 patients, with both stone composition analysis and 24-hour urine collection, seen between March 2002 and April 2012. Analysis of 24-hour urine constituents across the 3 stone groups (pure UA, pure CaOx, and mixed CaOx/UA) was performed using univariate analysis of variance and multivariate linear regression models adjusting for clinical and demographic factors and 24-hour urine collection elements., Results: A total of 27 patients (11.6%) had mixed CaOx/UA, 122 (52.6%) had pure CaOx, and 83 (35.8%) had pure UA calculi. Univariate analysis demonstrated significant differences between mixed CaOx/UA patients and pure CaOx patients for urine pH (mixed, 5.63 ± 0.49 vs pure, CaOx 5.93 ± 0.51; P = .009) and supersaturation (SS) UA (mixed, 1.84 ± 1.09 vs pure, CaOx 1.26 ± 0.93; P = .01), and a significant difference between mixed CaOx/UA patients and pure UA patients for SS CaOx (mixed, 7.18 ± 4.23 vs pure, UA 4.90 ± 2.96; P = .005). Multivariate analysis demonstrated that mixed CaOx/UA patients had no significant difference in SS CaOx as compared with pure CaOx patients (difference, -0.27; P = .66), whereas at the same time had no significant difference in SS UA as compared with pure UA patients (-0.07; P = .69)., Conclusion: The metabolic profile of patients who form mixed CaOx/UA stones demonstrates abnormalities that promote both CaOx and UA stone formation. Dietary and medical management for this group of patients should address treatment of both defects., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background and Purpose: Over the past 50 years, there has been an upward shift in the age of peak incidence of stone disease, yet less is known regarding how the urinary biochemical profile changes with aging. Therefore, we sought to examine the relationship between age and 24-hour urine composition., Methods: We retrospectively reviewed a database of our tertiary care stone clinic patients seen from March 2002 to February 2012. Analysis of pretreatment 24-hour urine collections across age groups was performed using univariate analysis of variance and multivariate linear regression models adjusting for clinical and demographic factors and 24-hour urine parameters., Results: A total of 1115 patients were broken down into age groups consisting of <45 years (221; 19.7%), 45-54.9 years (270; 23.8%), 55-64.9 years (270; 24.6%), and ≥65 years (356; 31.9%). Univariate analysis found significant ascending trends with aging for mean body mass index, while mean urine pH, 24-hour calcium, uric acid (UA), ammonium, creatinine, and supersaturation (SS) of calcium oxalate (CaOx) and calcium phosphate (CaP) decreased with age (all P for trend <0.05). Adjusted multivariate analysis demonstrated that increased age was significantly associated with increased 24-hour citrate and SS UA, whereas increased age was significantly associated with decreased pH, 24-hour UA, creatinine, SS CaOx, and SS CaP (all P for trend <0.05)., Conclusions: There are numerous age-related changes in the metabolic profile as seen on 24-hour urine collection. This highlights the importance of evaluating stone-forming patients of all ages with 24-hour urine collections because both the type and degree of metabolic abnormality may change with age.

Objective: To evaluate perspectives of urologists viewing live case demonstrations (LCD) and taped case demonstrations (TCD)., Method: A 15-question anonymous survey was distributed to attendees of the live surgery session at the American Urological Association 2012 national meeting (Atlanta) and the second International Challenges in Endourology meeting (Paris)., Results: Of 1000 surveys distributed, 253 were returned completed (response rate 25%). Nearly half of respondents were in the academic practice setting and nearly 75% were beyond training. Just over 30% had performed a LCD previously. The perceived benefit of an LCD was greater than unedited and edited videos (chi-squared P = 0.014 and P < 0.001, respectively). Nearly no one selected 'not helpful' and a few selected 'minimally helpful' for any of the three forms of demonstration. Most respondents identified that opportunity to ask questions (61%) and having access to the full unedited version (72%), two features inherent to LCD, improved upon the educational benefit of edited videos. Most (78%) identified LCD as ethical. However, those that did not perceived lower educational benefit from LCD (P = 0.019). A slim majority (58%) would allow themselves or a family member to be a patient of a LCD and the vast majority (86%) plan to transfer knowledge gained at the LCD session into their practice., Conclusions: Urologists who attended these LCD sessions identified LCDs as beneficial and applicable to their practice. LCDs are preferred over videos. The large majority considers LCD ethical, although not as many would volunteer themselves for LCD. Further studies are necessary to determine if there is actual benefit from LCD over TCD to patient care., (© 2013 The Authors. BJU International © 2013 BJU International.)

Calyceal diverticula are rare outpouchings of the upper collecting system that likely have a congenital origin. Stones can be found in up to 50% of calyceal diverticula, although, over the combined reported series, 96% of patients presented with stones. Diagnosis is best made by intravenous urography or computed tomography urogram. Shock wave lithotripsy (SWL) is an option for first-line therapy in patients with stone-bearing diverticula that have radiologically patent necks in mid- to upper-pole diverticula and small stone burdens. Stone-free rates are the lowest with SWL, although patients report being asymptomatic following therapy in up to 75% of cases with extended follow-up. Ureteroscopy (URS) is best suited for management of anteriorly located mid- to upperpole diverticular stones. Drawbacks to URS include difficulty in identifying the ostium and low rate of obliteration. Percutaneous management is best used in posteriorly located mid- to lower-pole stones, and offers the ability to directly ablate the diverticulum. Percutaneous nephrolithotomy remains effective in the management of upperpole diverticula, but carries the risk of pulmonary complications unless subcostal access strategies such as triangulation or renal displacement are used. Laparoscopic surgery provides definitive management, but should be reserved for cases with large stones in anteriorly located diverticula with thin overlying parenchyma, and cases that are refractory to other treatment. This article reviews the current theories on the pathogenesis of calyceal diverticula. The current classification is examined in addition to the current diagnostic methods. Here we summarize an extensive review of the literature on the outcomes of the different treatment approaches.

Purpose: We determined the accuracy of 24-hour urinalysis in predicting stone type and identify the associations between 24-hour urine elements with stone type., Materials and Methods: We performed a retrospective review of 503 stone formers with stone composition analysis and 24-hour urinalysis available. Analysis of 24-hour urine elements across stone types was performed using Fisher's exact test and ANOVA. Multinomial logistic regression was used to predict stone type based on 24-hour urinalysis., Results: A total of 280 (56%) patients had predominantly calcium oxalate, 103 (20%) had uric acid, 93 (19%) had calcium phosphate, 16 (3%) had mixed and 11 (2%) had other stone types. There were several significant patient characteristics and 24-hour urinalysis differences across stone type groups. The statistical model predicted 371 (74%) calcium oxalate, 78 (16%) uric acid, 52 (10%) calcium phosphate, zero mixed and 2 (less than 1%) other stone types. The model correctly predicted calcium oxalate stones in 85%, uric acid in 51%, calcium phosphate in 31%, mixed in 0% and other stone types in 18% of the cases. Of the predicted stone types, correct predictions were 61%, 69%, 56% and 71% for calcium oxalate, uric acid, calcium phosphate and other stones types, respectively. The overall accuracy was 64%. Plots were used to explore the associations between each 24-hour urine element with each predicted stone type adjusted for all the others urinary elements., Conclusions: A 24-hour urinalysis alone does not accurately predict stone type. However, it may be used in conjunction with other variables to predict stone composition., (Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the utility of two ipsilateral ureteral stents placed for benign and malignant ureteral obstruction., Methods: We performed a retrospective analysis of all cases of tandem ureteral stent (TUS) insertion at our institution from July 2007 through January 2013. Student t, Fisher exact, and log-rank test were used., Results: TUS insertion or exchange was performed in 187 cases. There were 66 patients (75 renal units) who underwent successful TUS insertion. Malignant ureteral obstruction (MUO) was the cause for obstruction in 39 renal units (34 patients) vs benign ureteral obstruction (BUO) in 36 renal units (32 patients). Four patients with BUO and 15 patients with MUO underwent stent exchanges at a mean 145 and 128 days, respectively. Serum creatinine levels were stable poststent placement (P=0.4). Degree of hydronephrosis improved (paired t test P<0.03) after stent placement for both benign and malignant cohorts. TUS placement was noted to fail (flank pain with worsening hydronephrosis or increasing creatinine level) in five renal units with MUO (12.8%) and none with BUO. Stent failure (either conventional or TUS) suggested worsening survival in those with MUO. Median survival for those with MUO and a history of stent failure (10 of 14 died, 71%) was 66 days compared with 432 days for those without a history of stent failure (8 of 20 died, 40%) (log-rank test P=0.007)., Conclusion: Our experience with the TUS, the largest to date, demonstrated that they are highly successful in both benign and malignant causes of obstruction, comparing favorably with metallic ureteral stents. Stent failure may be predictive for shorter survival.

Objective: To determine the differences in 24-hour urine composition between apatite and brushite stone formers., Methods: We conducted a retrospective review of 110 calcium phosphate (CaP) stone formers with both stone composition analysis and 24-hour urinalysis available. Analysis of 24-hour urine constituents between apatite and brushite stone formers was performed using univariable t test and multivariable linear regression models, adjusting for clinical and demographic factors., Results: A total of 97 patients (88%) had predominantly apatite stones and 13 patients (12%) had predominantly brushite stones. In univariable analysis, brushite stone formers had significantly higher mean 24-hour urinary calcium excretion (apatite = 204.8 ± 103.5 mg vs brushite = 329.7 ± 136.6 mg, P = .007), higher mean super saturation (SS) CaP (apatite = 1.423 ± 0.867 vs brushite = 2.576 ± 0.171, P = .004) and lower mean SS uric acid (apatite = 0.688 ± 0.796 vs brushite = 0.345 ± 0.190, P <.001). Similarly in multivariable analysis, brushite stone formers had significantly higher mean 24-hour urinary calcium excretion (mean difference = 135.1 mg, P <.001) and higher mean SS CaP (mean difference = 1.14, P <.001) but similar mean SS uric acid (mean difference = -0.37, P = .103). All other factors analyzed including body-mass index, urinary pH, volume, oxalate, citrate, sodium, potassium, magnesium, phosphate, chloride, ammonium, sulfate, uric acid, and SS calcium oxalate were similar between both stone groups., Conclusion: In a cohort of CaP stone formers, brushite stones were associated with higher urinary calcium excretion and higher urinary SS CaP when compared to apatite stones. Aggressive measures to reduce urinary calcium may be particularly helpful to prevent brushite stone formation., (Copyright © 2013 Elsevier Inc. All rights reserved.)