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Purpose: An accurate urinary predictor of stone recurrence would be clinically advantageous for patients with cystinuria. A proprietary assay (Litholink, Chicago, Illinois) measures cystine capacity as a potentially more reliable estimate of stone forming propensity. The recommended capacity level to prevent stone formation, which is greater than 150 mg/l, has not been directly correlated with clinical stone activity. We investigated the relationship between urinary cystine parameters and clinical stone activity., Materials and Methods: We prospectively followed 48 patients with cystinuria using 24-hour urine collections and serial imaging, and recorded stone activity. We compared cystine urinary parameters at times of stone activity with those obtained during periods of stone quiescence. We then performed correlation and ROC analysis to evaluate the performance of cystine parameters to predict stone activity., Results: During a median followup of 70.6 months (range 2.2 to 274.6) 85 stone events occurred which could be linked to a recent urine collection. Cystine capacity was significantly greater for quiescent urine than for stone event urine (mean ± SD 48 ± 107 vs -38 ± 163 mg/l, p <0.001). Cystine capacity significantly correlated inversely with stone activity (r = -0.29, p <0.001). Capacity also correlated highly negatively with supersaturation (r = -0.88, p <0.001) and concentration (r = -0.87, p <0.001). Using the suggested cutoff of greater than 150 mg/l had only 8.0% sensitivity to predict stone quiescence. Decreasing the cutoff to 90 mg/l or greater improved sensitivity to 25.2% while maintaining specificity at 90.9%., Conclusions: Our results suggest that the target for capacity should be lower than previously advised., (Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Intraoperative frozen section analysis is not routinely performed to determine positive surgical margins at radical prostatectomy due to time requirements and unproven clinical usefulness. Light reflectance spectroscopy, which measures light intensity reflected or backscattered from tissues, can be applied to differentiate malignant from benign tissue. We used a novel light reflectance spectroscopy probe to evaluate positive surgical margins on ex vivo radical prostatectomy specimens and correlate its findings with pathological examination., Materials and Methods: Patients with intermediate to high risk disease undergoing radical prostatectomy were enrolled. Light reflectance spectroscopy was performed on suspected malignant and benign prostate capsule immediately following organ extraction. Each light reflectance spectroscopy at 530 to 830 nm was analyzed and correlated with pathological results. A regression model and forward sequential selection algorithm were developed for optimal feature selection. Eighty percent of light reflectance spectroscopy data were selected to train a logistic regression model, which was evaluated by the remaining 20% data. This was repeated 5 times to calculate averaged sensitivity, specificity and accuracy., Results: Light reflectance spectroscopy analysis was performed on 17 ex vivo prostate specimens, on which a total of 11 histologically positive and 22 negative surgical margins were measured. Two select features from 700 to 830 nm were identified as unique to malignant tissue. Cross-validation when performing the predictive model showed that the optical probe predicted positive surgical margins with 85% sensitivity, 86% specificity, 86% accuracy and an AUC of 0.95., Conclusions: Light reflectance spectroscopy can identify positive surgical margins accurately in fresh ex vivo radical prostatectomy specimens. Further study is required to determine whether such analysis may be used in real time to improve surgical decision making and decrease positive surgical margin rates., (Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Current radio frequency ablation series do not distinguish renal cell carcinoma subtypes when reporting oncologic efficacy. Papillary neoplasms may be more amenable to radio frequency ablation than clear cell carcinoma because they are less vascular, which may limit heat energy loss. We report the long-term outcomes of patients treated with radio frequency ablation for small renal masses by renal cell carcinoma subtype., Materials and Methods: The records of patients undergoing radio frequency ablation for small renal masses (cT1a) at 2 institutions from March 2007 to July 2012 were retrospectively reviewed. Patients were included in analysis if they had biopsy confirmed clear cell or papillary renal cell carcinoma histology. Patients had at least 1 contrast enhanced cross-sectional image following radio frequency ablation. Demographic data between tumor subtypes were compared using the paired t-test. Oncologic outcomes were determined by Kaplan-Meier survival analysis and survivor curves were compared with the log rank test., Results: A total of 229 patients met study inclusion criteria. There were 181 clear cell tumors and 48 papillary tumors. Median followup was 33.2 months. There was no difference between tumor groups based on patient age, tumor size or grade, or months of followup. Five-year disease-free survival was 89.7% for clear cell tumors and 100% for papillary tumors (p = 0.041). There was no significant difference in overall survival (88.4% vs 89.6%, p = 0.764)., Conclusions: Radio frequency ablation outcomes seem to be determined in part by renal cell carcinoma subtype with clear cell renal tumors having less favorable outcomes. We hypothesize that this is due to differences in tumor vascularity. Our experience suggests that future tumor ablation studies should consider reporting outcomes based on tumor cell types., (Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Equivocal ureteropelvic junction obstruction refers to clinical symptoms and/or other radiological suggestions of possible ureteropelvic junction obstruction but with inconclusive results of obstruction on diuretic renogram. We evaluated long-term outcomes in patients with equivocal ureteropelvic junction obstruction treated with minimally invasive pyeloplasty., Materials and Methods: We retrospectively analyzed the records of 125 consecutive patients who underwent minimally invasive pyeloplasty as performed by a single surgeon from May 2004 to July 2013. Of 98 patients with followup those with more than 6-month followup were included in analysis. Equivocal ureteropelvic junction obstruction, defined as half-life less than 20 minutes on diuretic renogram, was identified in 23 patients. All patients underwent transperitoneal minimally invasive pyeloplasty. We evaluated patient demographics, preoperative and postoperative symptoms and renal function., Results: The 16 female and 7 male patients with equivocal ureteropelvic junction obstruction had flank pain and associated hydronephrosis on imaging. At a median followup of 20.2 months (range 7 to 75) 95.7% of patients with equivocal obstruction achieved complete symptom resolution. Mean ± SD preoperative and postoperative half-life was 14.1 ± 3.7 and 7.4 ± 4.2 minutes, respectively, for an improvement of 6.7 minutes (p < 0.001). In 1 patient (4.3%) with equivocal obstruction of a complicated iatrogenic etiology treatment ultimately failed postoperatively and endopyelotomy was required. There was no statistically significant difference in clinical or radiological success between the equivocal obstruction group and the 75 patients treated with minimally invasive pyeloplasty for definitive ureteropelvic junction obstruction (p = 0.44 and 0.07, respectively)., Conclusions: In patients with radiographic equivocal ureteropelvic junction obstruction and flank pain minimally invasive pyeloplasty efficaciously provides symptomatic relief and functional preservation. Results are comparable to those in patients with high grade obstruction., (Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Urine leak or obstruction in the early postoperative period is a worrisome complication of pyeloplasty. Suboptimal management may risk long-term success. We evaluated percutaneous nephrostomy to manage complications of minimally invasive pyeloplasty., Materials and Methods: We retrospectively analyzed the records of 125 patients who underwent minimally invasive pyeloplasty performed by a single surgeon from May 2004 to May 2013. All complications were catalogued and patients with anastomotic urine leakage or postoperative obstruction were identified. Less than 7 days postoperatively percutaneous nephrostomy was done in each case. Surgical success was defined as resolution of flank pain and/or improved half-time (less than 20 minutes) on diuretic renogram., Results: Early percutaneous nephrostomy placement was required in 12 patients (9.6%) for symptomatic obstruction (6) or anastomotic urine leakage (6) a median of 4.5 days (range 2 to 7) postoperatively. Percutaneous nephrostomies remained in place a median of 9.5 days (range 5 to 42). Median followup was 15 months (range 2 to 80). Mean half-time was 36.4 minutes preoperatively and 11.1 minutes postoperatively. Continued postoperative obstruction (half-time greater than 20 minutes) was documented in 1 (8%) and 13 patients (11.5%) who did and did not require percutaneous nephrostomy placement, respectively. There was no statistical difference in radiological and clinical success rates between the percutaneous nephrostomy group and the 113 patients in whom minimally invasive pyeloplasty was uncomplicated (p = 0.74 and 0.28, respectively)., Conclusions: In patients treated with minimally invasive pyeloplasty aggressive management of acute urinary complications with percutaneous nephrostomy placement preserved radiographic and symptomatic outcomes that were comparable to those in patients without complications., (Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We tested the relationship between caseload and total hospital charges after stratifying by minimally invasive and open radical prostatectomy., Materials and Methods: We evaluated 1,188 vs 3,354 men treated with minimally invasive vs open radical prostatectomy in the Florida Hospital Inpatients data file in 2008. Caseload was defined as the count of procedures performed by each surgeon between the study start on January 1, 2008 and the date of each procedure. Patients were divided into tertiles based on their procedure specific caseload. Univariate and multivariate analysis was done to address the relation between caseload and total hospital charges for the minimally invasive and open procedures. Covariates were patient age, race, comorbidity, and length of stay., Results: Median total hospital charges for minimally invasive and open radical prostatectomy were $33,234 and $33,674, respectively (p=0.03). Median total hospital charges in the low, intermediate and high minimally invasive vs open procedure caseload tertiles were $41,765, $34,799 and $28,780 vs $35,642, $34,726 and $32,726, respectively. On multivariate analysis with the high minimally invasive caseload tertile as the reference category the increments of the probability of charges in excess of the 2008 median of $33,588 were 3.9 and 8.1-fold for the intermediate and low caseload minimally invasive procedures, and 2.5, 3.6 and 2.8-fold for the high, intermediate and low caseload open procedures, respectively (each p<0.001)., Conclusions: Overall median total hospital charges are virtually the same for minimally invasive and open radical prostatectomy. However, total hospital charges for the minimally invasive procedure have a more sensitive caseload effect, as evidenced by the wider distribution of the median of minimally invasive caseload specific total hospital charges vs that of open radical prostatectomy. The high caseload minimally invasive procedure resulted in the lowest total hospital charges relative to all other minimally invasive and open radical prostatectomy categories., (Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Penile cancer is rare. Thus, predicting cancer specific mortality may be difficult. We devised an accurate and yet easily applicable predictive rule that compares favorably with 2 previous models (73.8% and 74.7% accuracy, respectively)., Materials and Methods: We identified patients treated with primary tumor excision for all stages of penile squamous cell carcinoma between 1998 and 2006. Disease stage definitions using Surveillance, Epidemiology and End Results stage, American Joint Committee on Cancer stage and TNM classification, and tumor grade were used to predict cancer specific mortality. Predictive accuracy estimates were compared using the DeLong method for related AUCs., Results: Surveillance, Epidemiology and End Results stage alone (1 predictor variable) was least accurate (74.5%). American Joint Committee on Cancer stage with tumor grade (2 predictor variables) was the most simple and most accurate (80.9%, p <0.001). A benefit similar to that of American Joint Committee on Cancer stage with tumor grade was seen for TNM classification and TG (80.7%, p = 0.8). However, this rule (4 predictor variables) was more complex than American Joint Committee on Cancer stage and tumor grade., Conclusions: American Joint Committee on Cancer stage combined with tumor grade is the simplest, most accurate cancer specific mortality prediction rule after primary tumor excision for penile squamous cell carcinoma. This method is also more accurate than 2 previous cancer specific mortality prediction rules., (Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Radical prostatectomy is the standard of care for localized prostate cancer. Numerous previous reports show the relationship between surgical experience and various outcomes. We examined the effect of surgical experience on complications and transfusion rates, and determined individual surgeon annual caseload trends in a contemporary radical prostatectomy cohort., Materials and Methods: We analyzed annual caseload temporal trends in 34,803 patients who underwent surgery between 1999 and 2008 in Florida. Logistic regression models controlled for clustering among surgeons addressed the relationship of surgical experience, defined as the number of radical prostatectomies done since January 1, 1999 until each radical prostatectomy, with complications and transfusions., Results: During the study period the proportion of surgeons in the high annual caseload tertile (24 radical prostatectomies or greater yearly) and the proportion of patients treated by those surgeons increased from 5% to 10% and from 20% to 55%, respectively. Conversely complication and transfusion rates decreased from 14.3% to 9.2% and 12.6% to 6.9%, respectively. Radical prostatectomies done by surgeons in the high surgical experience tertile (86 or greater radical prostatectomies) decreased the risk of any complication by 33% and of any transfusion by 30% vs those in patients operated on by surgeons in the low surgical experience tertile (27 or fewer radical prostatectomies)., Conclusions: The proportion of surgeons in the high annual caseload tertile and the proportion of patients treated by these surgeons steadily increased during the last decade. Complication and transfusion rates decreased with time. The implications of these encouraging findings may result in improved outcomes in patients with surgically managed prostate cancer., (Copyright © 2010 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)