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Purpose: Patients with recurring kidney stone events can expect significant morbidity and functional impairment. Few studies have evaluated the effect of bilateral kidney stones on disease progression and quality of life. We wanted to determine the association of bilateral stone disease on age of onset, and the impact on number of stone events and individual kidney stone disease-specific health-related quality of life (HRQOL) by analyzing the validated and prospectively collected Wisconsin Stone Quality of Life (WISQOL) database. Materials and Methods: We studied 2906 stone patients from 16 centers in North America after having completed the WISQOL questionnaire from 2014 to 2019. Kidney stone formers were assessed if kidney stones were bilateral or unilateral on imaging. Analysis with a chi-square test compared categorical variables. Bilateral kidney stone disease and its impact on HRQOL were evaluated through a multivariable linear regression model. Results: Of 2906 kidney stone formers, 1340 had unilateral kidney stones and 1566 had bilateral kidney stones. We observed more frequently that patients with bilateral stones had an increased number of depression/anxiety symptoms, renal tubular acidosis, and rheumatoid arthritis (all p  < 0.05). Patients with bilateral stones had a younger mean (standard deviation [SD]) age of kidney stone disease onset (37.2 ± 15.8 vs 46.4 ± 15.9 years of age, p  < 0.001). Bilateral kidney stone formers had a higher mean (SD) number of stone events (11.3 ± 21.8) than unilateral kidney stone formers (3.0 ± 5.1) ( p  < 0.001). Within our multivariable analysis, we found that HRQOL was negatively affected by the presence of bilateral stones for kidney stone patients ( β  = -11.2 [confidence interval: -19.5 to -3.0] points, p  < 0.05). Conclusions: Bilateral kidney stone formers had a younger age of kidney stone disease onset and a higher number of stone events compared with unilateral kidney stone disease formers. The presence of bilateral kidney stone disease negatively impacted HRQOL.

Introduction: Simple prostatectomy (SP) and laser enucleation of the prostate (LEP) are treatments for symptomatic benign prostatic hyperplasia (BPH) in men with large glands (e.g., >80 g). The decision between the two operations is often dependent on surgeon preference/experience and equipment availability. As the use of minimally invasive techniques, such as robotic-assisted simple prostatectomy, has increased for the treatment of large gland BPH, studies comparing the outcomes and cost of these modalities in a contemporary cohort are lacking. Methods: All-payer data from Healthcare Cost and Utilization Project State Databases from Florida, New York, California, and Maryland from 2016 to 2018 were used to identify adults who underwent SP or LEP for BPH. Patient demographics, facility characteristics, revisit rates, and cost of the index hospitalization were examined. Multivariable logistic and gamma generalized linear regression models were utilized to compare predictors of the operation performed, 30-day revisits, and index hospitalization cost among the two operations. Results: Of the 2032 patients in the cohort, 1067 (46.4%) underwent LEP and 965 (41.9%) underwent SP. On multivariable logistic regression analysis, SP patients were younger, had higher comorbidity scores, and were more likely to be uninsured compared with LEP patients. Thirty-day revisit rates among the operations were equivalent (odds ratio 0.89, 95% confidence interval 0.63-1.27, p  = 0.05). The mean adjusted cost of the index hospital stay for LEP was significantly greater than that of SP ($7291 vs $6442, p  = 0.04). However, our sub-group analysis examining high-volume centers revealed no significant differences in cost ($6184 vs $5353, p  = 0.1). Conclusions: Across the four states examined, SP and LEP were performed with comparable volume and had similar rates of 30-day revisits. The SP was less expensive than LEP overall; however, among high-volume facilities, the cost of both operations was reduced, such that they were equivalent.

Introduction: With a 5-year stone recurrence rate of 30% to 50%, kidney stone formers are subject to significant morbidity that negatively impacts their health-related quality of life (HRQOL). We sought to determine the impact of age at kidney stone onset, duration of stone disease, and kidney stone event (surgery or stone passage) on HRQOL of individual patients by querying the validated and prospectively collected Wisconsin Stone Quality of Life (WISQOL) database. Patients and Methods: Cross-sectional data were obtained from a total of 2438 kidney stone formers from 14 institutions in North America who completed the WISQOL questionnaire during the period from 2014 to 2019. The 28-question survey has a 1- to 5-point scale for each item (total score range 0-140). Multivariable linear regression models assessed the impact of age at kidney stone onset, duration of stone disease, and time since most recent surgery or stone passage on HRQOL. Results: Of 2438 patients, older age at kidney stone onset and longer duration of disease were both independent predictors of better WISQOL scores ( β  = 0.33 points/year; confidence interval [CI] 0.17-0.49; p  < 0.001; and β  = 0.50 points/year; CI 0.32-0.68; p  < 0.001, respectively). Of 1376 patients who underwent surgery between 2010 and 2019, longer time since most recent surgery was an independent predictor of better WISQOL scores ( β  = 2.28 points/year; CI: 1.47-3.10; p  = <0.001). Of 1027 patients with spontaneous stone passage occurring between 2010 and 2019, longer time since most recent stone passage was an independent predictor of better WISQOL scores ( β  = 1.59 points/year; CI: 0.59-2.59; p  = <0.05). Conclusions: Our study demonstrates that older age at onset, longer duration of disease, and longer time since most recent surgery or stone passage were independent predictors of better HRQOL in kidney stone formers. Results of future studies that focus on optimizing stone-related modifiable risk factors to decrease the number of recurrent stone episodes and thus the need for recurrent surgeries will be essential.

Objective: To examine the effects of care fragmentation, or the engagement of different health care systems along the continuum of care, on patients with urinary stone disease., Methods: All-payer data from the 2016 Healthcare Cost and Utilization Project (HCUP) State Databases from Florida (FL) and New York (NY) were used to identify a cohort of adult patients with an emergency department visit for a diagnosis of urolithiasis, who subsequently re-presented to an index or non-index hospital for renal colic and/or urological intervention. Patient demographics, regional data, and procedural information were collected and 30-day episode-based costs were calculated. Multivariable logistic and gamma generalized linear regression were utilized to identify predictors of receiving subsequent care at an index hospital and associated costs, respectively., Results: Of the 33,863 patients who experienced a subsequent encounter related to nephrolithiasis, 9593 (28.3%) received care at a non-index hospital. Receiving subsequent care at the index hospital was associated with fewer acute care encounters prior to surgery (2.5 vs 2.7; P <.001) and less days to surgery (29 vs 42; P < .001). Total episode-based costs were higher in the non-index setting, with a mean difference of $783 (Non-index: $13,672, 95% CI $13,292-$14,053; Index: $12,889, 95% CI $12,677 - $13,102; P < .001)., Conclusion: Re-presentation to a unique healthcare facility following an initial diagnosis of urolithiasis is associated with a greater number of episode-related health encounters, longer time to definitive surgery, and increased costs., (Copyright © 2022 Elsevier Inc. All rights reserved.)

To evaluate the impact of chronic stone recurrence on an individual's quality of life using the validated Wisconsin Stone Quality of Life (WISQOL) questionnaire. We collected cross-sectional data on patients with kidney stones from 14 institutions in North America. A stone event was defined as renal colic, stone-related procedure or emergency department visit. The regression analyses using general linear models and pairwise comparison determined the impact of the number of stone events on quality of life. The median number of stone events among the 2205 patients who completed the questionnaire was 3 (IQR 1-6). The mean total score was 107.4 ± 28.7 (max 140 points). The number of lifetime stone events was an independent predictor of lower quality of life (p < 0.001), specifically, score declined significantly beyond five events. Compared with patients who experienced a single stone event, there was a 0.4, 2.5, and 6.9 point decline in the adjusted mean WISQOL score after 2-5, 6-10, or > 10 events, respectively. The cumulative number of lifetime stone events was associated with a lower quality of life when more than five stone events were occurred. These findings underscore the importance of efforts to determine the underlying metabolic etiology of urolithiasis in the recurrent stone former, and the institution of a regimen to place their stone disease in remission., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Objective: To build the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA) to predict urolithiasis patients' health-related quality of life (HRQoL) based on demographic, symptomatic and clinical data collected for the validation of the Wisconsin Stone Quality-of-Life (WISQOL) questionnaire, an HRQoL measurement tool designed specifically for patients with kidney stones., Material and Methods: We used data from 3206 stone patients from 16 centres. We used gradient-boosting and deep-learning models to predict HRQoL scores. We also stratified HRQoL scores by quintile. The dataset was split using a standard 70%/10%/20% training/validation/testing ratio. Regression performance was evaluated using Pearson's correlation. Classification was evaluated with an area under the receiver-operating characteristic curve (AUROC)., Results: Gradient boosting obtained a test correlation of 0.62. Deep learning obtained a correlation of 0.59. Multivariate regression achieved a correlation of 0.44. Quintile stratification of all patients in the WISQOL dataset obtained an average test AUROC of 0.70 for the five classes. The model performed best in identifying the lowest (0.79) and highest quintiles (0.83) of HRQoL. Feature importance analysis showed that the model weighs in clinically relevant factors to estimate HRQoL, such as symptomatic status, body mass index and age., Conclusions: Harnessing the power of the WISQOL questionnaire, our initial results indicate that the WISQOL-MLA can adequately predict a stone patient's HRQoL from readily available clinical information. The algorithm adequately relies on relevant clinical factors to make its HRQoL predictions. Future improvements to the model are needed for direct clinical applications., (© 2020 The Authors BJU International © 2020 BJU International.)

Introduction: Health-related quality of life (HRQOL) is decreased in patients with kidney stones at all stages of stone disease, even when asymptomatic. Stress is thought to contribute to HRQOL, although there has been minimal investigation into the effect of stress on stone-related quality of life (QOL). We used the Wisconsin Stone Quality of Life Questionnaire (WISQOL) to assess the relationship of stress to stone-related QOL in kidney stone patients., Methods: As part of the WISQOL Research Consortium, patients were approached in outpatient clinics and completed the WISQOL and the Perceived Stress Scale 10-item questionnaire (PSS-10). Patients with stones at enrollment were divided into those with symptoms and those without, while patients with no current stones formed another group. Questionnaire scores from each group were compared statistically and correlations between the groups were calculated., Results: Patients (n=704) were enrolled from six centers. The WISQOL successfully discriminated between patients with current stones and those without (p<0.0001), while the PSS-10 did not (p=0.0869). The PSS-10 revealed patients with symptomatic kidney stones experienced higher levels of general stress than asymptomatic subjects (p<0.0001). However, a Pearson correlation test comparing the responses from each instrument revealed no overall correlation between general stress and HRQOL (r=0.05)., Conclusions: Symptomatic kidney stones increase general stress, as these patients demonstrate higher PSS-10 scores. Despite this, no correlation exists between general stress and stone-related QOL in patients with stone disease regardless of their stone and symptom status. This implies the existence of other factors impacting QOL in these patients, which warrants further exploration.

Purpose: Metabolic syndrome (MetS) is a cluster of metabolic diseases that is linked to atherosclerotic cardiovascular disease. MetS has also been linked to increased nephrolithiasis. However, limited research has been conducted on MetS and its impact on stone-specific health-related quality of life (HRQOL). This study aims to examine the hypothesis that the presence of MetS is associated with decreased HRQOL. Materials and Methods: The Wisconsin Stone Quality of Life Questionnaire, a stone-specific HRQOL questionnaire, was used to survey 3051 patients with kidney stones. Medical history was collected from patients. These data were used to distinguish MetS patients from non-MetS patients. Among patients with current stones, a Wilcoxon rank sum test was used to compare HRQOL scores from MetS patients and non-MetS patients. HRQOL from patients with and without individual MetS components were also compared, and a multivariate analysis was conducted. Results: Statistical comparison between MetS patients (median score 102/140) and non-MetS patients (median score 106/140) demonstrated a lower stone-specific HRQOL in patients with MetS ( p  = 0.049). Among individual MetS components, patients with diabetes mellitus (DM) or body mass index (BMI) >30 had significantly lower HRQOL than patients without DM or BMI <30 ( p  = 0.028 and p  < 0.001, respectively). The multivariate analysis supported this trend as MetS remained a significant predictor of decreased HRQOL ( p  = 0.002) after controlling for other variables assessed. Conclusions: This study indicates an association between MetS and a lower stone-specific QOL. This has important implications for stone prevention strategies in patients with MetS. Clinical Trial Registration number: H14-01143.

Introduction: Urolithiasis causes a significant impact on health-related quality of life (HRQOL). Patients with kidney stones have high levels of stress and anxiety. Symptom resolution often requires treatment. Travel distance is a barrier to care but little is known about its effects on HRQOL. We hypothesize that increased distance to treatment site is associated with decreased HRQOL., Methods: Patients with a history of stones were enrolled at 11 tertiary centers as part of the QOL Stone Consortium of North America. HRQOL data were obtained using the Wisconsin Stone Quality of Life questionnaire (WISQOL). We calculated distance between patient and treatment site using national ZIP codes. We used linear models to evaluate the effect of distance on HRQOL, while also considering demographics data, stones/symptom status, and distance., Results: Of the 1676 enrolled patients, 52% were male, 86% non-Latino White, and the mean age was 53 years. Mean distance to treatment site was 63.3 km (range 0-3774), with 74% reporting current stones and 45% current symptoms. WISQOL score and distance were negatively correlated for patients reporting current stones and symptoms (p=0.0010). Linear modelling revealed decreased WISQOL scores for patients with symptoms as distance increased from treatment site (p=0.0001), with a 4.7-point decrease for every 100 km traveled., Conclusions: Stone disease imposes significant burden on patients' HRQOL due to a variety of factors. Patients with active stone symptoms report worse HRQOL with increased distance to their treatment site. Possible etiologies include travel burden, increased disease burden, decreased healthcare use, and delays in care.

Purpose: Kidney stone formers have lower health related quality of life than nonstone formers. The North American Stone Quality of Life Consortium is a multicenter, longitudinal, prospective study of health related quality of life in patients with kidney stones using the WISQOL (Wisconsin Stone Quality of Life Questionnaire) with data on 2,052 patients from a total of 11 centers. This study is a subanalysis of cross-sectional data looking at the association of age, gender and race on health related quality of life of stone formers., Materials and Methods: We performed multivariable analyses of ordinal logistic regression analyses to determine the impact of age, gender and race on health related quality of life, adjusting for other baseline covariates. The proportional odds assumption of ordinal logistic regression was checked. Total score and scores on 4 subdomains (social functioning, emotional functioning, stone related impact and vitality) were included., Results: Median total score for all patients was 80.4. On multivariable analysis older patients had a significantly higher total health related quality of life score than younger patients (per 10-year increase OR 1.25, p <0.0001). Male patients had higher scores than females (OR 1.56, p = 0.0003) and nonCaucasian patients had lower health related quality of life than nonLatino Caucasian patients (OR 0.63, p = 0.0045)., Conclusions: Younger and female patients with kidney stones have lower health related quality of life than older and male patients, respectively. NonCaucasian patients with stones also have lower health related quality of life. The clinical impact of these findings might include future implications for patient counseling, including dietary and medical management of stone disease, and potential changes to the paradigm of the surgical management of stones.

Purpose: Kidney stones are a source of significant morbidity which have been shown to negatively impact health related quality of life. We sought to understand the association between health related quality of life, socioeconomic status and race among patients with kidney stones., Materials and Methods: Patients with stones at a total of 11 stone centers across the United States completed the WISQOL (Wisconsin Stone Quality of Life questionnaire). The patient ZIP Code™ was used to estimate household income. A mixed effects regression model was constructed for analysis with ZIP Code as the random intercept., Results: A total of 2,057 stone formers completed the WISQOL. Lower income was independently associated with significantly lower health related quality of life (β = 0.372, p = 0.014), as were nonwhite race (β = -0.299, p = 0.001), unemployed work status (β = -0.291, p = 0.008), female gender (β = -0.204, p <0.001), body mass index greater than 40 kg/m 2 (β = -0.380, p <0.001), 5 or more medical comorbidities (β = -0.354, p = 0.001), severe recurrent stone formation (β = -0.146, p = 0.045), enrollment at an acute care visit, or a preoperative or postoperative appointment (β = -0.548, p <0.001) and recent stone symptoms (β = -0.892, p <0.001)., Conclusions: Lower income, nonwhite race and unemployed work status were independently associated with lower health related quality of life among patients with kidney stones. While clinical characteristics such as body mass and stone disease severity were also associated with health related quality of life, this study shows that socioeconomic factors are similarly important. Further research to understand the specific mechanisms by which socioeconomic status and race impact health may lend insight into methods to optimize clinical treatment of stone formers and patients with other chronic diseases.

Purpose: To our knowledge it is unknown whether the benefits of medical management of urolithiasis outweigh the potential side effects of the medications used, including potassium citrate and thiazide diuretics. Therefore, we evaluated the relationship between potassium citrate or thiazides and overall stone related health related quality of life., Materials and Methods: Cross-sectional data were obtained on stone forming enrollees in the North American Stone Quality of Life Consortium. We used the WISQOL (Wisconsin Stone Quality of Life) questionnaire to compare health related quality of life between patients treated and not treated with potassium citrate or thiazide type diuretics. Additionally, the likelihood of gastrointestinal complaints was compared between those prescribed and not prescribed potassium citrate. The likelihood of fatigue and sexual complaints was also compared in those prescribed and not prescribed thiazides., Results: Of the 1,511 subjects, including 787 males and 724 females, 279 were on potassium citrate and 238 were on thiazides at study enrollment. Patients prescribed potassium citrate had higher health related quality of life in each domain vs those not prescribed potassium citrate (p <0.001). Patients prescribed thiazides had higher health related quality of life in each domain compared to those not prescribed thiazide (all p <0.01). Those prescribed potassium citrate were less likely than those not prescribed potassium citrate to report nausea, stomach upset or cramps (OR 0.57, p <0.001). Patients prescribed thiazides were less likely than those not prescribed thiazides to report fatigue (OR 0.63, p = 0.004) or reduced sexual interest and/or activity (OR 0.64, p = 0.005)., Conclusions: Among stone formers the use of potassium citrate and thiazides was associated with better health related quality of life across all WISQOL domains without an increased likelihood of gastrointestinal complaints and fatigue or sexual complaints, respectively. These findings may be useful when counseling patients regarding the initiation of potassium citrate or thiazides for medical management of nephrolithiasis., (Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: WISQOL (Wisconsin Stone Quality of Life questionnaire) is a disease specific, health related quality of life measure designed for patients who form kidney stones. The purpose of this study was to demonstrate the external and convergent validity of WISQOL and assess its psychometric properties., Materials and Methods: At the WISQOL creation site (development sample) and at 8 geographically diverse centers in the United States and Canada (consortium sample) patients with a history of kidney stones were recruited. Item response option variability, correlation patterns and internal consistency were compared between samples. Convergent validity was assessed by patients who completed both WISQOL and SF-36v2® (36-Item Short Form Health Survey, version 2)., Results: Results were analyzed in 1,609 patients, including 275 in the development sample and 1,334 in the consortium sample. Response option variability patterns of all items were acceptable. Internal WISQOL consistency was acceptable. Intersample score comparisons revealed few differences. For both samples the domain-total WISQOL score correlations exceeded 0.86. Item level analyses demonstrated suitable variation, allowing for discriminatory scoring. At the time that they completed WISQOL, patients with stones and stone related symptoms scored lowest for health related quality of life. Patients with stones but no symptoms and those with no stones scored higher. The convergent validity substudy confirmed the ability of WISQOL to identify stone specific decrements in health related quality of life that were not identified on SF-36v2., Conclusions: WISQOL is internally consistent and discriminates among patients with different stone statuses and symptoms. WISQOL is externally valid across the North American population. It may be used for multicenter health related quality of life studies in kidney stone disease., (Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: Urinary diversion and augmentation cystoplasty are associated with long-term complications, including metabolic derangements, infectious complications, and urolithiasis. The aim of this series was to characterize upper and lower urinary tract (LUT) calculi in this population., Methods: A retrospective chart review was performed on all patients with a history of urinary diversion or augmentation cystoplasty who subsequently underwent treatment for urolithiasis between January 1998 and May 2015. Data collected included demographics, perioperative characteristics, type of reconstructive procedure, urine culture, stone analysis, and metabolic evaluation. A statistical analysis was performed., Results: Ninety-nine patients were identified with a history of urolithiasis and incontinent urinary diversion (28), neobladder (21), continent cutaneous diversion (12), and augmentation cystoplasty (38). LUT stones were more common than upper tract stones in all except for incontinent diversions, which only had one lower tract stone (p = 0.0001). Twenty-three percent of stones were metabolic. Several metabolic derangements were noted, including hypocitraturia (100%), elevated urine pH (100%), low urine volume (70%), and hyperoxaluria (35%). There was a 44% rate of recurrent urolithiasis., Conclusions: Given the high rate of stone recurrence among patients with a history of urinary diversion and augmentation cystoplasty, all measures should be taken to prevent recurrent stones. In addition to actions aimed to prevent infectious stones such as bladder and pouch irrigation, we recommend these patients undergo a full metabolic workup with targeted dietary changes and medical therapies.

Background and Purpose: Laparoscopic pyeloplasty has emerged as the gold standard for repair of ureteropelvic junction obstruction. Microlaparoscopic (MLP, <3 mm) instrumentation has improved markedly and can now be used for suturing and complex dissection needed during laparoscopic pyeloplasty. We present our experience with microlaparoscopy compared with conventional laparoscopy for transperitoneal pyeloplasty., Methods: We performed a retrospective analysis of hybrid MLP, using a 5-mm camera in a hidden umbilical incision, and 1.9 or 3 mm working instruments and compared with patients undergoing conventional laparoscopic pyeloplasty (CLP). The data for MLP and CLP were compared using the Student t test, Pearson chi-square test, and Fisher exact test, where appropriate., Results: Between January 2009 and May 2013, there were 19 MLP and 27 CLP procedures performed. The MLP group mean age was younger than the CLP group (34 vs 50 years; P=0.0003). Body mass index, previous treatment rates, operative time, length of stay, ureteral stent duration, and complication rates were not statistically different between the MLP and CLP groups. Strict success rates (indicated by follow-up renal scan T½<20 min) were similar between MLP and CLP groups (89.5% vs 88.9%; P=0.95). No MLP procedures were converted to CLP or open approaches., Conclusions: From technical, perioperative, and outcome perspectives, transperitoneal pyeloplasty with microlaparoscopy is both safe and feasible in our hands compared with conventional laparoscopy, and results in subjectively superior cosmesis. This is the largest MLP series to date and contains, to our knowledge, the only cases described using prototype 1.9 mm instruments.

Background and Purpose: Use of the robotic platform for urinary reconstructive surgery is growing in popularity since its initial application with pyeloplasty for ureteropelvic junction (UPJ) repair. Although clinical series of adult robotic ureteral reconstruction appear in the literature, these reports tend to be limited in size and scope. We present the largest series to date of patients undergoing surgery for any obstruction distal to the UPJ along with outcomes and short-term follow up., Patients and Methods: A retrospective chart review was performed for patients undergoing robotic ureteral reconstructive procedures for any indication at our institution. Patients undergoing pyeloplasty, planned open procedures, and pediatric patients were excluded from the current analysis. Patient demographic data, etiology, procedure performed, and perioperative outcomes were reviewed. Postoperative follow up, imaging, and any re-interventions were also captured. The procedures performed included ureteroneocystostomy, psoas hitch, Boari flap, ureteroureterostomy, ureterolysis, ureterolithotomy, and nephropexy., Results: A total of 55 patients underwent robotic ureteral reconstructive procedures distal to the UPJ. Of these patients, 45 underwent intervention for a benign etiology and 10 for upper tract malignancy. All cases were successfully completed robotically with no open conversions and no intraoperative complications. Concurrent endoscopy was performed in 31 patients. The median operating room time was 221 minutes overall. Median blood loss was 50 ml with no intraoperative transfusions. The average hospital stay was 1.6 days, with 39 patients (71%) discharged on postoperative day 1. All surgical margins were negative for malignancy. The median follow up with imaging was 181 days. There were two serious complications (3.6%) and three failures (5.3%)., Conclusions: Robotic reconstruction of the ureter distal to the UPJ is feasible, safe, effective, and able to replicate techniques of open surgery with equivalent outcomes to large robotic pyeloplasty and smaller distal ureteral reconstruction series.

Increased urinary volume decreases recurrence rates of nephrolithiasis. Current recommendations for goal volumes are not adjusted to reflect individual risk factors, such as obesity. Our intent was to develop and evaluate a goal urine volume for stone prevention based on predictive calcium modeling. Stone formers with a 24-h urine study (6/2001-9/2010) were identified. Patients with inadequate collections or non-calcium stones were excluded. Multivariate and univariate predictive models for daily calcium were evaluated and a univariate (weight) model was selected. A target calcium concentration constant (2.5 mM) was determined from current recommendations. Individualized weight-based goal urine volumes (WGUV) were calculated. Measured calcium concentration and expected calcium concentrations using a 2-L goal volume and WGUV were compared. 185 of 399 patients met inclusion criteria. Body weight was a strong predictor of calcium excretion in each model (p < 0.0001). While a 2-L goal urine volume would be expected to improve mean calcium concentrations for the cohort from 3.53 to 2.96 mM, the benefit is unequal between subsets with nearly twofold expected concentration for the highest weight quartile (3.98 vs. 2.10 mM) and higher expected concentration for males (3.35 vs. 2.59 mM). By contrast, a WGUV model improves expected concentrations for all subsets to <2.9 mM and the overall cohort to 2.50 mM. This study demonstrates a strong relationship between body weight and urinary calcium excretion in stone formers. We introduce the novel concept of individualized goal urine output using statistical modeling, which may be preferable to current recommendations.

Background and Purpose: Cumulative radiation exposure from imaging studies is hazardous. In chronic diseases such as urolithiasis, efforts are made to limit radiation exposure, particularly for routine surveillance. We sought to determine the correlation of ultrasonography (US) compared with noncontrast CT (NCCT) in detecting and determining size of stones., Patients and Methods: Findings were evaluated in patients who underwent both imaging modalities within a 90-day period between July 2008 and June 2010. Urinary calculi were noted on NCCT in 72 patients. The sensitivity of US to determine the number, size, and location of the stones as described on official radiology reports were compared in reference to NCCT., Results: There were 203 urinary calculi in 90 urinary tracts identified on NCCT imaging. The sensitivity, specificity, and accuracy of detecting specific stones on US were 40%, 84%, and 53%. Correlation between US and NCCT findings decreased with smaller stone size and ureteral location and increased with right-sided laterality. For identified stones, larger stone size discrepancies were noted in up to one-third of stones on US., Conclusions: Despite concern for excessive radiation exposure, urologists should recognize limitations of US in the evaluation of urolithiasis. As the ideal study to image stones, particularly for routine surveillance, remains unclear, tese data also supports the need for low-dose NCCT protocols and/or selective use of alternative modalities, such as magnetic resonance urography.

Purpose: The 2005 American Urological Association Guideline on the Management of Staghorn Calculi suggests that metabolic stones are uncommon in the composition of staghorn calculi. We determined the incidence and treatment outcomes of metabolic stones in patients with complete staghorn calculi compared to infection stones in those undergoing percutaneous nephrolithotomy., Materials and Methods: We retrospectively analyzed all patients who underwent percutaneous nephrolithotomy for complete staghorn calculi between April 2005 and April 2010. Stone analysis was reviewed to classify stone type as infectious or metabolic. Perioperative characteristics and patient outcomes were compared in relation to stone composition., Results: Of 52 kidneys (48 patients) with complete staghorn calculi 29 (56%) were metabolic and 23 (44%) were infection stones. Stone compositions in the metabolic group were calcium phosphate (55%), uric acid (21%), calcium oxalate (14%) and cystine (10%). Patients with metabolic stones were more likely male (55% vs 17%, p = 0.005) and more likely to have a negative preoperative urinary culture (62% vs 35%, p = 0.05). Patients with metabolic stones had a lower complication rate (p = 0.02), while those with infection stones tended to require additional access and secondary treatment, and to have higher recurrence rates. Multiple urinary metabolic abnormalities were noted in all 13 (48%) patients with metabolic stones who completed evaluation., Conclusions: In a contemporary cohort of patients, metabolic stones comprised a large proportion of complete staghorn calculi. In our series calcium phosphate was the most common stone composition noted. Metabolic stones should be considered during the evaluation of staghorn calculi, and our results underscore the importance of stone analysis and subsequent metabolic evaluation in these patients., (Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We describe our multi-institutional experience using a laparoscopic clamp to induce selective regional ischemia during robot-assisted laparoscopic partial nephrectomy (RALPN) without hilar occlusion., Patients and Methods: A retrospective review of Institutional Revew Board-approved databases of patients who underwent selective regional clamping during RALPN at four institutions was performed., Results: In 20 patients who were treated for elective indications, RALPN with parenchymal clamping was successful in 17 (85%). Mean age was 63 years (24-78 y). Median tumor diameter was 2.2 cm (1.1-7.2 cm). Mass location was polar in 13 (76%) and interpolar in 4 (24%). Median R.E.N.A.L. nephrometry score was 6 (4-10). Median overall operative time was 190 minutes (129-309 min), while selective clamp time was 26 minutes (19-52 min). Collecting system repair occurred in 8 (47%) patients. No patients needed a blood transfusion. There was no significant difference in preoperative (median 86 mL/min/1.73 m(2)) and immediate postoperative glomerular filtration rate (GFR) (median 78 mL/min/1.73 m(2), P=0.33) or with the most recent GFR (median 78 mL/min/1.73 m(2), P=0.54) at a mean follow-up of 6.1 months (1.2-11.9 mos). Final pathology determination revealed renal-cell carcinoma in 71% with no positive margins on frozen or final evaluation. In three additional patients who were undergoing RALPN, bleeding because of incomplete distal clamp compression necessitated subsequent central hilar clamping for the completion of the procedure., Conclusions: In our preliminary multi-institutional experience, regional ischemia using a laparoscopic parenchymal clamp is feasible during RALPN for hemostasis. Careful preoperative selection of patients is needed to determine ideal patient and tumor characteristics. Further comparison studies are necessary to determine the true utility of this technique.

Introduction: Central to any image-guided surgical procedure is the alignment of image and physical coordinate spaces, or registration. We explored the task of registration in the kidney through in vivo and ex vivo porcine animal models and a human study of minimally invasive kidney surgery., Methods: A set of (n = 6) ex vivo porcine kidney models was utilized to study the effect of perfusion and loss of turgor caused by incision. Computed tomography (CT) and laser range scanner localizations of the porcine kidneys were performed before and after renal vessel clamping and after capsular incision. The da Vinci robotic surgery system was used for kidney surface acquisition and registration during robot-assisted laparoscopic partial nephrectomy. The surgeon acquired the physical surface data points with a tracked robotic instrument. These data points were aligned to preoperative CT for surface-based registrations. In addition, two biomechanical elastic computer models (isotropic and anisotropic) were constructed to simulate deformations in one of the kidneys to assess predictive capabilities., Results: The mean displacement at the surface fiducials (glass beads) in six porcine kidneys was 4.4 ± 2.1 mm (range 3.4-6.7 mm), with a maximum displacement range of 6.1 to 11.2 mm. Surface-based registrations using the da Vinci robotic instrument in robot-assisted laparoscopic partial nephrectomy yielded mean and standard deviation closest point distances of 1.4 and 1.1 mm. With respect to computer model predictive capability, the target registration error was on average 6.7 mm without using the model and 3.2 mm with using the model. The maximum target error reduced from 11.4 to 6.2 mm. The anisotropic biomechanical model yielded better performance but was not statistically better., Conclusions: An initial point-based alignment followed by an iterative closest point registration is a feasible method of registering preoperative image (CT) space to intraoperative physical (robot) space. Although rigid registration provides utility for image-guidance, local deformations in regions of resection may be more significant. Computer models may be useful for prediction of such deformations, but more investigation is needed to establish the necessity of such compensation.

Purpose: We previously described the use of cold saline surface irrigation to achieve protective renal hypothermia in a laparoscopic partial nephrectomy porcine model. We now present our clinical application of this technique and characterization of the hypothermic effect during laparoscopic partial nephrectomy., Materials and Methods: Seven patients underwent elective laparoscopic partial nephrectomy augmented with our hypothermia technique. Parenchymal temperature sensors were placed to confirm cooling efficacy and efficiency. After transperitoneal exposure of the kidney we performed temporary hilar vascular occlusion. Surface cooling with almost freezing normal saline was delivered with a laparoscopic suction/irrigation device. Tumor laparoscopic resection and renal reconstruction were completed. Outcome measures included intraoperative changes with hypothermia and postoperative estimated glomerular filtration rate changes., Results: All patients successfully underwent laparoscopic partial nephrectomy without complications or evidence of residual disease. A protective renal parenchymal temperature of less than 20C was achieved at a mean application time of 8.3 minutes. The hypothermic window of 15C to 25C was maintained an average of 30.4 minutes. In 2 cases cooling was repeated and 4 minutes were required to lower the temperature below 20C. The overall mean core body temperature decrease was 1.28C. At a mean followup of 22.4 months the median preoperative, immediate postoperative and final estimated glomerular filtration rate was 75, 65 and 71 ml/minute/1.73 m(2), respectively. There was no evidence of disease recurrence on followup imaging., Conclusions: Our technique involving cold saline surface irrigation to achieve protective renal hypothermia is reproducible, and uses readily available laparoscopic instruments and equipment. This technique can be done simply and effectively, and may expand the use of laparoscopic partial nephrectomy., (Copyright © 2010 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Ureteral stent placement during adult laparoscopic pyeloplasty for ureteropelvic junction obstruction can be performed preoperatively or intraoperatively either in a retrograde or antegrade approach. Intraoperative retrograde stent placement is the most commonly used technique. Comparative studies, however, suggest that there is a significant component added to the overall operative times because of the need for patient repositioning from the lithotomy to the flank position before pyeloplasty. During our laparoscopic pyeloplasty surgery, we position the patient in the lateral decubitus position and incorporate a lower extremity support device for female patients. This allows initial open-ended catheter placement and subsequent access to the perineum and final stent placement throughout the procedure without need for patient repositioning. In addition, our technique allows for intraoperative fluoroscopy to delineate the complete ureteral anatomy. Since 2004, we have used this approach in 111 consecutive patients without complications. We describe our technique for intraoperative ureteral stent placement in the flank position during adult laparoscopic pyeloplasty without need for patient repositioning.

Objectives: To describe our early experience using a laparoscopic clamp to induce selective regional ischemia during robotic-assisted partial nephrectomy without hilar occlusion. The creation of a bloodless field during minimally invasive approaches to nephron-sparing surgery often requires complete warm ischemia with renal hilar clamping that can potentially result in subsequent renal damage., Methods: After transperitoneal renal mobilization and delineation of the renal tumor margin using laparoscopic ultrasound, the laparoscopic clamp is placed across the renal parenchyma 2-3 cm proximal to the resection line. After tumor excision, the renal defect is repaired robotically and hemostatic agents are used to aid in achieving compressive hemostasis., Results: Three patients with predominantly exophytic renal masses underwent this procedure for elective indications. Mean tumor diameter was 4.9 cm (range 1.2-7.0). Mean selective clamp time was 37 minutes (range 20-52). Estimated blood loss was minimal and no patients required renal hilar clamping. There were no perioperative complications. Mean change in preoperative and postoperative creatinine was 0.1 (±0.09). Final pathology revealed clear cell and papillary renal carcinomas with no positive margins on frozen or final evaluation., Conclusions: Regional renal parenchymal clamping during robotic partial nephrectomy can be safely and effectively used to create a bloodless operative field in select patients with optimally located renal tumors. Our early experience with this technique allows for frozen pathologic evaluation of the tumor and margin status without concern for warm ischemia and represents another tool for surgeons performing minimally invasive nephron-sparing surgery., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Objectives: Radiofrequency ablation (RFA)-assisted laparoscopic partial nephrectomy (LPN) may allow for improved hemostasis without need for renal hilar vessel clamping and elimination of warm ischemia to the kidney. We compare outcomes in patients undergoing radiofrequency ablation-assisted robotic clampless partial nephrectomy (RF-RCPN) and LPN., Methods: Thirty-six patients and 42 patients underwent LPN and RF-RCPN, respectively. In the RF-RCPN group, the Habib 4x RFA device was used to coagulate a margin of normal parenchyma around the renal mass to allow excision of the mass within a bloodless plane. Unlike in the LPN group, renal hilar vascular occlusion was not performed in the RF-RCPN group., Results: Tumors treated in the RF-RCPN group tended to be larger (2.8 vs. 2.0 cm) and more often endophytic (52.6% vs. 16.1%). Collecting system reconstruction occurred more often in the RF-RCPN group (78.6% vs. 30.6%). Operative duration was longer in the RF-RCPN group (373 vs. 250 minutes), but this included time for cystoscopy, ureteral stenting, and repositioning of the patient. Blood loss, transfusion rates, renal function, and complication rates did not differ between the two groups. No patients required renal hilar vessel clamping or nephrectomy to control bleeding in the RF-RCPN group., Conclusions: The use of RFA-assistance during robotic partial nephrectomy allows excision of renal tumors without hilar vascular clamping, thus eliminating renal warm ischemia. Larger and more centrally located tumors were excised with RF-RCPN. No differences in blood loss, complication rate, postoperative bleeding, renal function, or recurrence rate were noted compared with LPN.

Laparoscopic nephroureterectomy (LNU) is becoming an increasingly common alternative treatment for transitional cell carcinoma (TCC) of the renal pelvis and ureter due to decreased perioperative morbidity, shorter hospitalization, and comparable oncologic control with open nephroureterectomy (ONU). Mobilization of the kidney and proximal ureter may be performed through a transperitoneal, retroperitoneal, or hand-assisted approach. Each technique is associated with its own benefits and limitations, and the optimal approach is often dictated by surgeon preference. Our analysis of the literature reflects equivalent cancer control between LPN and OPN at intermediate follow-up with significantly improved perioperative morbidity following LPN. Several methods for bladder cuff excision have been advocated, however, no individual technique for management of the distal ureter proved superior. Overall, complete en-bloc resection with minimal disruption of the urinary tract should be optimized to maintain oncologic outcomes. Longer follow-up and prospective studies are needed to fully evaluate these techniques.

Background and Purpose: Minimally invasive approaches to manage bladder diverticula have become increasingly popular; however, intracorporeal identification of bladder diverticula may be challenging. We report a novel technique for diverticular illumination using flexible cystoscopy., Patients and Methods: After management of bladder neck obstruction, two patients with bladder diverticula and persistent lower urinary tract symptoms underwent robot-assisted bladder diverticulectomy. Cystoscopic illumination was used in both cases to aid diverticular identification and dissection., Results: Our technique was simple to perform and facilitated identification and dissection of bladder diverticula. Postoperative cystography revealed no evidence of residual diverticula., Conclusions: Cystoscope-assisted illumination provides a straightforward method of identifying bladder diverticula during robot-assisted laparoscopic diverticulectomy.

We present a unique case of primary urothelial carcinoma with both histological and immunohistochemical features similar to thyroid papillary carcinoma. Following surgical resection of the primary tumor and localized metastatic lymphadenectomy, the patient was treated with a course of adjuvant chemotherapy. No evidence of primary thyroid carcinoma was noted. The patient was without recurrence after a 6 month follow-up.

Background: Randomized trials have shown an improvement in progression-free survival rates with adjuvant radiation therapy (ART) after radical prostatectomy for patients with a high risk of cancer recurrence. Less is known about the relative advantages and disadvantages of initial observation with delayed salvage radiation therapy (SRT)., Objective: To examine the results of SRT in a large single-surgeon radical prostatectomy series., Design, Setting, and Participants: From a radical prostatectomy database, we identified 859 men with positive surgical margins (SM+), extracapsular tumor extension (ECE), or seminal vesicle invasion (SVI) who chose to defer ART. Following a period of initial observation, 192 ultimately received SRT for prostate-specific antigen (PSA) progression., Measurements: Survival analysis was performed to examine the outcomes of initial observation followed by SRT., Results and Limitations: In patients with SM+/ECE and SVI, the 7-yr PSA progression-free survival rates with observation were 62% and 32%, respectively. Among those who had PSA progression, 56% and 26%, respectively, maintained an undetectable PSA for 5 yr after SRT. The long-term rates of undetectable PSA associated with an SRT strategy were 83% and 50% for men with SM+/ECE and SVI, respectively. In the subset of 716 men who did not receive any hormonal therapy, the corresponding long-term rates of undetectable PSA were 91% and 75%, respectively., Conclusions: Following radical prostatectomy, initial observation followed by delayed SRT at the time of PSA recurrence is an effective strategy for selected patients with SM+/ECE. Some patients with SVI may also benefit from this strategy. However, additional prospective studies are necessary to further examine the survival outcomes following SRT.

We describe a modified technique of standard cystoscopic manipulation to facilitate bladder stone extraction. This technique decreases the overall time required for stone manipulation by allowing larger size stone fragments to be removed from the urethra under direct visualization.