24-Hour Urine Calcium Oxalate Supersaturation Risk Correlates with Computerized Tomography Volumetric Calcium Oxalate Stone Growth.

PURPOSE: In vitro experiments demonstrate calcium oxalate (CaOx) supersaturation (SS) drives CaOx nucleation and growth. We investigated the link between 24-hour urine SS CaOx and in vivo stone growth through a natural history, imaging study. MATERIALS AND METHODS: Using an institutional review board-approved database, we sought >80% CaOx stone formers who prior to stone intervention obtained 2 separate computerized tomography (CT) scans with at least one 24-hour urine collection between scans. Two blinded reviewers calculated bilateral 3-dimensional stone volume using the Visage 7® region of interest pen tool. CT volume difference was divided by time between scans, and SS CaOx was grouped into low (<5), medium (5-10) and high risk (>10). Statistical significance between groups was assessed by Kruskal-Wallis test. RESULTS: We identified 80 individuals with stone growth measured by 3-dimensional CT (mean ∼7 months between studies). Inter-reviewer reliability of CT volume measurement was well correlated (0.98, Gwet's AC2), and an arbitrator was only needed in 13/160 (8%) cases. Median stone volume growth/year was 15%, 71% and 177% for low, medium and high risk groups, respectively (p <0.001). Despite inter-individual variation, best fit of mean SS CaOx vs stone volume growth was moderately correlated (Spearman's rho=0.53, p <0.001). CONCLUSIONS: In a population of pure CaOx stone formers, increased 24-hour SS CaOx risk was associated with increased in vivo stone growth. Further investigations using CT volumetric stone growth may allow for the noninvasive study of stone growth modulators, improved stone risk prediction and development of a kidney stone simulator.

Long-term Recurrence Rates in Uric Acid Stone Formers With or Without Medical Management.

OBJECTIVE: To determine if medical therapy affects long-term clinical outcomes in uric acid stone formers (UASF). METHODS: We identified 53 UASF who had complete stone clearance following stone procedure by computed tomography (CT) and had ≥1 postoperative 24-hour urine collection and a clinical follow-up ≥6 months with a surveillance CT scan. Patients were divided into "adherent to medical therapy" (compliance with potassium citrate ± allopurinol verified by computerized pharmacy data) or nonadherent groups. Primary outcomes were CT stone recurrence rate and need for surgical stone intervention. RESULTS: We found 28 of 53 (53%) adherent and 25 of 53 (47%) nonadherent individuals (14 declined medication, 11 intolerant). With median follow-up of 24 months, no significant differences were noted between groups in regards to stone recurrence (32%; P = .99) or in 24-hour urine pH compared to baseline or follow-up (range 5.46-5.62; P = 0.06). Adherent patients, however, had smaller CT stone recurrence sizes (6.3 ± 3.8 vs 11.8 ± 6.2 mm, P = .02), were 28% less likely to require stone surgery compared to those without therapy (P <.01), and trended toward longer time intervals without recurrence (23.1 ± 18.8 vs 10.5 ± 7.5 months, P = .10) compared to nonadherents. Study confounders included a variety of medication dosages and adherences, limited nonadherent follow-up, and small study number. CONCLUSION: UASF adherent to medical therapy had smaller recurrence sizes and fewer surgical interventions vs nonadherent, highlighting the protective role of potassium citrate in UA stone disease. The comparable urine pH and stone recurrence rates between groups, however, underscore areas for improvement in future UA stone prevention strategies.

The Effect of Continued Low Dose Aspirin Therapy in Patients Undergoing Percutaneous Nephrolithotomy.

PURPOSE: Aspirin is often stopped prior to percutaneous nephrolithotomy due to concern about the surgical bleeding risk. There is evidence that discontinuing aspirin perioperatively increases thromboembolic events and continuing it may be safe. We assessed the effect of continuing low dose aspirin through percutaneous nephrolithotomy and its effect on surgical and safety outcomes. MATERIALS AND METHODS: We retrospectively reviewed the records of 285 consecutive percutaneous nephrolithotomies performed between 2012 and 2015 at our institution. We compared outcomes and complications in patients who continued 81 mg aspirin daily to those in patients not receiving aspirin. RESULTS: A total of 67 patients (24.5%) were maintained on low dose aspirin and 207 (75.5%) were not on aspirin. The aspirin group was older (66 vs 52 years), included more tobacco users (58.2% vs 31.4%) and had a higher ASA® (American Society of Anesthesiologists®) score (2.9 vs 2.5, all p <0.001). There was no difference in mean S.T.O.N.E. (size, topography [stone location], obstruction, number of stones and evaluation of HU) score (7.6 vs 7.7, p = 0.71) or blood loss (44 vs 54 ml, p = 0.151). There was no difference in residual stone fragment size, including 0 to 2 mm in 65.3% vs 61.4% of aspirin vs no aspirin cases, 3 to 4 mm in 19.4% vs 16.2% and greater than 4 mm in 15.3% vs 22.4% (p = 0.407). Length of stay and the change in hemoglobin, hematocrit and creatinine were similar. There was no difference in the readmission rate (14.9% vs 12.6%, p = 0.618) or the total complication rate (34.4% vs 26.6%, p = 0.221). There was also no difference in the number of major complications (10.4% vs 5.8%, p = 0.193), bleeding complications (3.0% vs 2.9%, p = 0.971) and the transfusion rate (1.5% vs 1.0%, p = 0.57). CONCLUSIONS: Percutaneous nephrolithotomy appears effective and safe in patients who continue low dose aspirin perioperatively.

Age, Body Mass Index, and Gender Predict 24-Hour Urine Parameters in Recurrent Idiopathic Calcium Oxalate Stone Formers.

INTRODUCTION AND OBJECTIVE: Despite guidelines, routine 24-hour urine testing is completed in <10% of high-risk, recurrent stone formers. Using surrogates for metabolic testing, such as key patient characteristics, could obviate the cost and burden of this test while providing information needed for proper stone prevention counseling. METHODS: We performed a retrospective study of 392 consecutive patients from 2007 to 2014 with ≥2 lifetime stone episodes, >70% calcium oxalate by mineral analysis, and ≥1 24-hour urine collection. We compared mean 24-hour urine values by age in decades. We used logistic regression and receiver operating characteristic (ROC) curve analysis to assess the predictive ability of age, gender, body mass index (BMI), and comorbidities to detect abnormal 24-hour urine parameters. RESULTS: The mean age of the cohort was 51 ± 16 years. Older age was associated with greater urinary oxalate (p-trend <0.001), lower urinary uric acid (UA) (p-trend = 0.007), and lower urinary pH (p-trend <0.001). A nonlinear association was noted between age and urinary calcium or citrate (calcium peaked at 40-49 years, p = 0.03; citrate nadired at 18-29 years, p = 0.001). ROC analysis of age, gender, and BMI to predict 24-hour urine abnormalities performed the best for hyperuricosuria (area under the curve [AUC] 0.816), hyperoxaluria (AUC 0.737), and hypocitraturia (AUC 0.740). Including diabetes mellitus or hypertension did not improve AUC significantly. CONCLUSIONS: In our recurrent calcium oxalate cohort, age significantly impacted urinary calcium, oxalate, citrate, and pH. Along with gender and BMI, age can be used to predict key 24-hour urine stone risk results. These data lay the foundation for a risk prediction tool, which could be a surrogate for 24-hour urine results in recurrent stone formers, who are unwilling or unable to complete metabolic testing. Further validation of these findings is needed in other stone populations.

Prostate cancer risk estimation tool use by members of the American Urological Association: a survey based study.

PURPOSE: Prostate cancer risk estimation tools have been developed to help guide patients and physicians with clinical decision making across all disease states. We assessed use patterns of these tools using an online survey sent to AUA (American Urological Association) members. MATERIALS AND METHODS: We distributed a 21-question online survey to 5,674 AUA members to query prostate cancer risk estimation tool use. The survey was divided into 4 categories, including 1) demographics, 2) prebiopsy risk assessment, 3) pretreatment risk assessment and 4) risk estimation tool use. RESULTS: A total of 565 members (10%) responded to the online survey, of whom 31% reported using a risk estimation tool in the prebiopsy decision setting. Providers who spent more than 20 minutes counseling patients were more likely to use a risk estimation tool (OR 2.2, p <0.01). After the prostate cancer diagnosis 70% of providers used a risk estimation tools to guide treatment recommendations. The total time spent counseling a patient (greater than 30 minutes) and the number of years in practice (fewer than 10) predicted prostate cancer risk tool use (OR 2.4, p <0.01 and 3.4, p <0.01, respectively). CONCLUSIONS: AUA respondents use risk estimation tools more frequently in the pretreatment setting than in the prebiopsy setting. The time spent counseling patients and the time since graduation from residency predicted the likelihood of using risk estimation tools.

A retrospective review of office-based 532-nm GreenLight laser prostatectomy in men with symptomatic benign prostatic hyperplasia.

OBJECTIVE: To evaluate the feasibility, safety, and outcomes of men with symptomatic benign prostatic hyperplasia undergoing 532-nm GreenLight laser prostatectomy in the office-based setting. MATERIALS AND METHODS: From September 2007 to October 2011, 47 patients underwent office-based 532-nm GreenLight laser prostatectomy by a single surgeon. Patients were enrolled prospectively and preoperative, intraoperative, and postoperative parameters were then reviewed retrospectively. Statistical analysis was performed with Wilcoxon rank sum test with a P value ≤.05 being considered statistically significant. RESULTS: The mean patient age was 66 (range, 49-89); 91% of men were on an alpha-blocker preoperatively; mean (standard deviation; SD) prostate volume by transrectal ultrasound was 35.8 mL (14.5); mean (SD) American Society of Anesthesiologists score was 2.33 (0.77); mean (SD) operative time was 36.73 minutes (18); mean (SD) lasing time was 19.1 minutes (8.31); mean (SD) total laser kiloJoules used was 85,387 kJ (38,885); and mean (SD) follow-up time was 8.48 months (8.24). The 1-year decrease in mean (SD) American Urologic Association Symptom Score and quality of life were 17.7 (8.3)-7 (7.3) and 4.1 (1.4)-2.27 (2) respectively. The maximal urinary flow increased from 8.1 (3.8) to 10.7 (6). Patients' postvoid residual improved from 130 mL (147) to 27 mL (55) over a 1-year period. (P <.01 for all). There were no reoperations for refractory lower urinary tract symptoms or hospital admissions. CONCLUSION: For men with small but symptomatic benign prostatic enlargement, office-based GreenLight laser prostatectomy is safe and feasible.

Early oncological outcomes for bladder urothelial carcinoma patients treated with robotic-assisted radical cystectomy.

OBJECTIVE: • To determine oncological outcomes including early survival rates among unselected bladder urothelial carcinoma (BUC) patients treated with robotic-assisted radical cystectomy (RRC). PATIENTS AND METHODS: • Clinicopathologic and survival data were prospectively gathered for 85 consecutive BUC patients treated with RRC. • The decision to undergo a robotic rather than open approach was made without regard to tumor volume or surgical candidacy. • Kaplan-Meier survival rates were determined and stratified by tumor stage and LN positivity, and multivariate analysis was performed to identify independent predictors of survival. RESULTS: • Patients were relatively old (25% >80 years; median 73.5 years), with frequent comorbidities (46% with ASA class ≥ 3). Of these patients 28% had undergone previous pelvic radiation or pelvic surgery, and 20% had received neoadjuvant chemotherapy. • Extended pelvic lymphadenectomy was performed in 98% of patients, with on average 19.1 LN retrieved. • On final pathology, extravesical disease was common (36.5%). • Positive surgicalmargins were detected in five (6%) patients, all of whom had extravesical tumors with perineural and/or lymphovascular invasion, and most of whom were >80 years old. • At a mean postoperative interval of 18 months, 20 (24%) patients had developed recurrent disease, but only three (4%) patients had recurrence locally. Disease-free, cancer-specific and overall survival rates at 2 years were 74%, 85% and 79%, respectively. Patients with low-stage/LN(-) cancers had significantly better survival than extravesical/LN(-) or any-stage/LN(+) patients, with stage being the most important predictor on multivariate analysis. CONCLUSION: • RRC can achieve adequately high LN yields with a low positive margin rate among unselected BUC patients. • Early survival outcomes are similar to those reported in contemporary open series, with an encouragingly low incidence of local recurrence, however long-term follow-up and head-to-head comparison with the open approach are still needed.

The emerging role of robotics in adrenal surgery.

Robotic surgery is being performed more frequently for a variety of urologic procedures. Since the first robotic adrenalectomy less than a decade ago, this modality has gained increased acceptance in the urologic community and has been employed with increased frequency in minimally invasive centers. This review evaluates the current literature on robotic adrenalectomy, its indications, as well as its advantages and limitations compared with other forms of surgical management of adrenal pathology.

A comparison of postoperative complications in open versus robotic cystectomy.

BACKGROUND: Robotic cystectomy is an emerging alternative for treatment of invasive bladder cancer (BCa). However, reduction in postoperative morbidity relative to the open approach has not been demonstrated. OBJECTIVE: To compare complication rates in patients undergoing robotic versus open radical cystectomy (RC). DESIGN, SETTING, AND PARTICIPANTS: A prospective cohort study of 187 consecutive patients undergoing RC at our institution-104 open RC, 83 robotic RC. INTERVENTION: Open or robotic RC with urinary diversion. MEASUREMENTS: Demographic, perioperative, and complication data were recorded prospectively. Thirty-day and 90-d complication rates were assessed using the modified Clavien complication scale. Data were evaluated using chi(2) and multivariate logistic regression analyses. RESULTS AND LIMITATIONS: At 30 d, the open group demonstrated a higher overall complication rate (59% vs 41%; p=0.04) as well as more major complications (30% vs 10%; p=0.007). At 90 d, the overall complication rate was greater in the open group, but this was not statistically significant (62% vs 48%; p=0.07). However, there was a significantly higher major complication rate in the open cohort (31% vs 17%; p=0.03). When subjected to logistic regression analysis, robotic cystectomy was an independent predictor of fewer overall and major complications at 30 and 90 d. High American Society of Anesthesiologists (ASA) score (3-4) and longer surgical time were independent predictors of major complications. Though this is one of the largest published RC series, the sample size is relatively small. Moreover, despite the two patient cohorts being similarly matched, the study was not performed in a randomized fashion. CONCLUSIONS: Patients undergoing robotic cystectomy experienced fewer postoperative complications than those undergoing open cystectomy. Robotic cystectomy is an independent predictor of fewer overall and major complications. Until long-term oncologic results are available, robotic cystectomy should still be considered investigational.

Critical analysis of complications after robotic-assisted radical cystectomy with identification of preoperative and operative risk factors.

OBJECTIVE: To better characterize short- and long-term complications in patients after robotic-assisted radical cystectomy (RRC) using standardized complications-reporting systems, and to identify preoperative and operative risk factors predicting their occurrence. PATIENTS AND METHODS: Data were collected for 79 consecutive patients with bladder cancer undergoing RRC with extracorporeal urinary diversion by one surgeon at our institution. Complications occurring < or =90 days after RRC were graded according to two standardized reporting methods (Memorial Sloan Kettering Cancer Center and Modified Clavien), and additionally stratified by organ system. Nineteen preoperative and operative variables were tested by univariate analysis for association with the occurrence of one or more postoperative complications. Variables with a significant (P < 0.05) or near-significant (P < 0.20) association on univariate analysis were included in multivariate analysis to identify independent risk factors. RESULTS: Patients were of relatively poor health, with 58% having an American Society of Anesthesiology class or Charlson Index score of > or =3. Advanced bladder disease was frequent (41% had pT3/pT4). After RRC, one or more complications occurred within 90 days of surgery for 39/79 (49%) patients. The vast majority of complications were low grade (79%), and mostly infectious (41%) or gastrointestinal (27%). Sixteen high-grade complications occurred in 13/79 (16%) patients. Urinary obstruction, abscess, enteric fistula, gastrointestinal bleeding and thromboembolism constituted most of the high-grade complications, nearly half (seven of 16) of which occurred 31-90 days after RRC. On multivariate analysis, only preoperative renal insufficiency and intraoperative intravenous (i.v.) fluids of >5000 mL were significantly associated with postoperative complications of any grade, with respective odds ratios (ORs) of 4.2 and 4.1. For high-grade complications, significant independent risk factors included an age of > or = 65 years, operative blood loss of > or =500 mL and intraoperative i.v. fluids of >5000 mL, with respective ORs of 12.7, 9.7 and 42.1. CONCLUSION: Even among relatively sick patients with frequent advanced disease, the vast majority of complications after RRC are low grade. High-grade complications are infrequent and similar in nature to high-grade events after open RC, and a notable proportion may occur at >30 days after RRC underscoring the importance of longer reporting intervals. The surgeon's ability to limit blood loss and i.v. fluids during RRC may provide effective risk reduction, particularly for high-grade events.