Localized Urinary Bladder Amyloidosis as Urothelial Cancer Mimicker.

CONTEXT.­: Localized amyloidosis of the bladder is rare and often mimics bladder malignancy. It is typically associated with the extracellular deposition of monoclonal light chains, either κ or λ. The cause is unknown, but it is thought to be due to chronic inflammation/cystitis. OBJECTIVE.­: To highlight the importance of localized urinary bladder amyloidosis as a rare mimicker of urothelial malignancy and elucidate its clinical, histopathologic, and cytopathologic manifestations. DESIGN.­: Cases of urinary bladder amyloidosis diagnosed during 2000-2023 were retrieved retrospectively from pathology archives. Electronic medical records, including cystoscopy findings and pathology slides including Congo red stain, were reviewed. RESULTS.­: Here we present 6 patients with localized urinary bladder amyloidosis. Four of the 6 patients were women, with ages ranging from 46 to 69 years, and a mean age of 58 years. Five of 6 patients presented with hematuria, while in 1 patient, bladder amyloidosis was discovered incidentally. Cystoscopy findings invariably were concerning for malignancy, with raised erythema in 5 patients and fungating mass protruding into the bladder lumen in 1 patient. Bladder biopsies and urine cytology were negative for malignancy in all cases. Congo red-positive amyloid deposits involved lamina propria with sparing of the detrusor muscle. In 5 cases, the deposits were typed as derived from the λ light chain, whereas no information was available for 1 patient. Subsequent clinical workup ruled out systemic amyloidosis. CONCLUSIONS.­: These cases of urinary bladder amyloidosis highlight the importance of considering rare amyloidosis in the differential diagnosis of hematuria and cystoscopy with a lesion mimicking malignancy.

Comparison of Work Relative Value Units Assigned to Urological and Gynecological Surgical Procedures.

INTRODUCTION: We sought to determine if work relative value unit differences exist between analogous, sex-specific procedures. METHODS: Representatives from the AUA and the American College of Obstetricians and Gynecologists independently reviewed the entire procedural code set and identified sex-specific procedures that had an analogous procedure in the opposite sex. These pairs were then evaluated and compared using current American Medical Association Relative Value Scale Update Committee methodology. Comparable code pair values were then examined to determine any systemic bias in the work relative value units assigned between the procedures. Mean differences and 95% confidence intervals were used to determine any differences in procedure or physician time values. The methodology used considered global period, intraservice time, total time, hospital days, postoperative office visits, and the date of the committee review. RESULTS: Of the 10 directly analogous code pairs reviewed, 7 of the female procedures had higher work relative value unit differences (range 0.29-6.47), and 3 of the male procedures had higher work relative value unit differences (range 1.23-2.34). There was no statistical difference between the code pair work relative value units. The work relative value unit per minute of intraservice time and total time were not statistically different. CONCLUSIONS: In this study, we compared operative procedures performed in women with clinically comparable operative procedures performed in men that had similar surgical approaches, global periods, and valuation methodologies. Overall, no statistical differences in work relative value units were demonstrated.

Metabolic syndrome and the urinary microbiome of patients undergoing percutaneous nephrolithotomy.

Objective: To identify possible stone-promoting microbes, we compared the profiles of microbes grown from stones of patients with and without metabolic syndrome (MetS). The association between MetS and urinary stone disease is well established, but the exact pathophysiologic relationship remains unknown. Recent evidence suggests urinary tract dysbiosis may lead to increased nephrolithiasis risk. Methods: At the time of percutaneous nephrolithotomy, bladder urine and stone fragments were collected from patients with and without MetS. Both sample types were subjected to expanded quantitative urine culture (EQUC) and 16 S ribosomal RNA gene sequencing. Results: Fifty-seven patients included 12 controls (21.1%) and 45 MetS patients (78.9%). Both cohorts were similar with respect to demographics and non-MetS comorbidities. No controls had uric acid stone composition. By EQUC, bacteria were detected more frequently in MetS stones (42.2%) compared to controls (8.3%) (p=0.041). Bacteria also were more abundant in stones of MetS patients compared to controls. To validate our EQUC results, we performed 16 S ribosomal RNA gene sequencing. In 12/16 (75.0%) sequence-positive stones, EQUC reliably isolated at least one species of the sequenced genera. Bacteria were detected in both "infectious" and "non-infectious" stone compositions. Conclusion: Bacteria are more common and more abundant in MetS stones than control stones. Our findings support a role for bacteria in urinary stone disease for patients with MetS regardless of stone composition.

Variability in prostate cancer detection among radiologists and urologists using MRI fusion biopsy.

Objectives: The aim of this study is to evaluate the impact of radiologist and urologist variability on detection of prostate cancer (PCa) and clinically significant prostate cancer (csPCa) with magnetic resonance imaging (MRI)-transrectal ultrasound (TRUS) fusion prostate biopsies. Patients and methods: The Prospective Loyola University MRI (PLUM) Prostate Biopsy Cohort (January 2015 to December 2020) was used to identify men receiving their first MRI and MRI/TRUS fusion biopsy for suspected PCa. Clinical, MRI and biopsy data were stratified by radiologist and urologist to evaluate variation in Prostate Imaging-Reporting and Data System (PI-RADS) grading, lesion number and cancer detection. Multivariable logistic regression (MVR) models and area under the curve (AUC) comparisons assessed the relative impact of individual radiologists and urologists. Results: A total of 865 patients (469 biopsy-naïve) were included across 5 urologists and 10 radiologists. Radiologists varied with grading 15.4% to 44.8% of patients with MRI lesions as PI-RADS 3. PCa detection varied significantly by radiologist, from 34.5% to 66.7% (p = 0.003) for PCa and 17.2% to 50% (p = 0.001) for csPCa. Urologists' PCa diagnosis rates varied between 29.2% and 55.8% (p = 0.013) and between 24.6% and 39.8% (p = 0.36) for csPCa. After adjustment for case-mix on MVR, a fourfold to fivefold difference in PCa detection was observed between the highest-performing and lowest-performing radiologist (OR 0.22, 95%CI 0.10-0.47, p < 0.001). MVR demonstrated improved AUC for any PCa and csPCa detection when controlling for radiologist variation (p = 0.017 and p = 0.038), but controlling for urologist was not significant (p = 0.22 and p = 0.086). Any PCa detection (OR 1.64, 95%CI 1.06-2.55, p = 0.03) and csPCa detection (OR 1.57, 95%CI 1.00-2.48, p = 0.05) improved over time (2018-2020 vs. 2015-2017). Conclusions: Variability among radiologists in PI-RADS grading is a key area for quality improvement significantly impacting the detection of PCa and csPCa. Variability for performance of MRI-TRUS fusion prostate biopsies exists by urologist but with less impact on overall detection of csPCa.

Using Intraoperative Portable CT Scan to Minimize Reintervention Rates in Percutaneous Nephrolithotomy: A Prospective Trial.

Background and Purpose: More than 40% of patients undergoing percutaneous nephrolithotomy (PCNL) are left with residual stone fragments and often require secondary procedures. Portable CT (PCT) technology allows surgeons to obtain intraoperative cross-sectional imaging, identify and extract residual stones immediately, and thereby reduce the need for subsequent procedures. This prospective trial evaluates how incorporation of PCT during PCNL affects perioperative outcomes. Patients and Methods: We prospectively enrolled eligible patients undergoing initial PCNL for this trial (n = 60), which entailed a single intraoperative CT abdomen and ipsilateral antegrade ureteroscopy when the surgeon felt stone treatment was visually complete. If residual fragments were identified, the surgeon continued nephroscopy to find and remove them; if not, the procedure was concluded. These patients were compared with a retrospective cohort (n = 174) who underwent initial PCNL with postoperative imaging performed the following day. Results: The two cohorts had similar demographic properties and stone characteristics, and location of percutaneous access. In the prospective arm, 50% of intraoperative PCT scans identified residual fragments, prompting continuation of surgery to remove them. This cohort had significantly higher stone-free rate (82% vs 36%, p < 0.01), lower rate of planned reintervention (7% vs 32%, p < 0.01), lower rate of urgent presentation with ureteral obstruction (0% vs 7%, p = 0.04), lower total CT-based effective radiation dose (8.4 mSv vs 14.6 mSv, p < 0.01), and shorter length of stay (2.3 days vs 3.5 days, p < 0.01) when compared with the retrospective cohort that did not use intraoperative PCT. Conclusions: Obtaining an intraoperative PCT scan during PCNL can substantially improve perioperative outcomes. Further evaluation of this modality through a randomized controlled trial is warranted. Clinical Trial Registration Number: NCT04556396.

Axial Diameter is Superior to Volumetric Measurement in Predicting Ureteral Stone Passage.

INTRODUCTION: We sought to investigate the clinical utility of volumetric measurements in predicting passage of symptomatic ureteral calculi. METHODS: We performed a retrospective review of patients seen in the emergency department for computerized tomography-confirmed symptomatic ureteral calculi with a subsequent discharge for trial of passage. Patient demographics and results of the passage trial were recorded. Stone parameters including location, 2-dimensional linear measurements and 3-dimensional volume measurements were calculated. Univariate and multivariate analyses were performed to evaluate the association between the aforementioned stone parameters and stone passage. RESULTS: A total of 70 patients were analyzed, of whom 37 (53%) passed their stones. On univariate analysis, patients who passed their stones had shorter axial diameters (mean±SD 3.3±1.3 mm vs 5.1±1.7 mm, p <0.01) and smaller volumes (0.03±0.02 cm3 vs 0.10±0.08 cm3, p <0.01). Stones that passed had traversed 79% of the ureter on presentation, compared to 41% for the stones that did not pass (p <0.01). Multivariate analysis demonstrated that shorter axial diameter was independently associated with stone passage (OR 0.46 [CI 0.29-0.71], p <0.01). Inclusion of stone volume measurements into the logistic regression model, however, provided no additional benefit for predicting stone passage rates (p=0.28). CONCLUSIONS: Although a stone's volume is expectedly correlated with passage, it does not seem to provide additional benefit when the stone's axial diameter and location within the ureter are known. Based on our findings, additional investment of time and resources into 3-dimensional modalities may not be warranted in this setting.

Proton-pump inhibitors associated with decreased urinary citrate excretion.

INTRODUCTION: Proton-pump inhibitors (PPIs) may increase the risk of kidney stone formation, but the mechanism has not been elucidated. There is a paucity of literature evaluating the effects of PPIs on urinary metabolites and urine pH. METHODS: We performed a retrospective review of nephrolithiasis patients treated at our institution and compared patients who were taking PPIs to those who were not at the time of their 24-h urine collections. Hierarchical multivariate linear regression was used to evaluate the independent relationship between PPI use and urinary mineral composition. RESULTS: We identified 301 consecutive patients, 88 (29%) of whom were taking PPIs at the time of their 24-h urine collections. Patients taking PPIs were older and more likely to have medical comorbidities associated with metabolic syndrome such as hypertension, diabetes, and dyslipidemia (p < 0.01). Controlling for these factors, patients taking PPIs were found to have 12% lower 24-h urine citrate excretion (ß = - 0.12, ΔF = 4.24, p = 0.04). There were no other differences in urinary mineral composition between the groups. CONCLUSION: Our findings suggest that patients who take PPIs regularly may be at risk for decreased urinary citrate excretion. The consequent decrease in urinary citrate may become clinically significant for patients with other predisposing factors for hypocitraturia.

Association of Impaired Renal Function With Changes in Urinary Mineral Excretion and Stone Composition.

OBJECTIVE: To investigate the effect of kidney function on stone composition and urinary mineral excretion in patients undergoing surgical intervention for nephrolithiasis. METHODS: Using our institutional kidney stone database, we performed a retrospective review of stone patients who underwent surgical intervention between 2004 and 2015. Patients' demographic information, 24-hour urinary mineral excretion, and stone characteristics were reported. The patients' estimated glomerular filtration rates (eGFR) were compared with their stone compositions and 24-hour urine mineral excretions. RESULTS: A statistically significant difference was noted between the groups, with uric acid stones being associated with lower eGFR and calcium phosphate stones associated with higher eGFR. No relationship could be demonstrated between eGFR and calcium oxalate or struvite stones. Patients with lower eGFR also demonstrated a statistically significant association with lower urinary pH as well as lower urinary excretion of calcium and citrate. CONCLUSION: While various factors have been found to play significant roles in kidney stone formation and composition, our findings demonstrate a definite relationship between these and renal function. This paper highlights the fact that renal function evaluation should be considered an important component in the evaluation, counseling, and management of patients with nephrolithiasis.

Paravertebral block for percutaneous nephrolithotomy: a prospective, randomized, double-blind placebo-controlled study.

PURPOSE: Percutaneous nephrolithotomy (PCNL) is performed commonly in patients with large kidney stones, but the management of their postoperative pain presents a major challenge. While it is not routinely performed in PCNL patients, paravertebral block (PVB) has been described as an effective strategy for pain control after various non-urologic surgeries. This trial aims to assess the effect of paravertebral blockade on intraoperative and postoperative opioid use as well as postoperative pain control in patients undergoing PCNL. METHODS: This was a prospective, randomized, double-blind, placebo-controlled study. Patients who consented to participate were randomly assigned to undergo either PVB or a placebo intervention preoperatively. The patient, surgeon, and anesthesia team were all blinded to the randomization. The outcome parameters were intraoperative opioid requirement, postoperative visual analog scale (VAS) pain scores, postoperative opioid use, and postoperative antiemetic use. RESULTS: 23 patients were enrolled in each arm of the study, and the two groups had no significant differences in baseline demographic or clinical characteristics. Patients in the PVB group had significantly lower intraoperative opioid use, postoperative opioid use, frequency of opioid use, and antiemetic. Patients in the PVB group also had lower postoperative VAS pain scores. There were no patients who suffered from complications attributable to PVB. CONCLUSION: The results of this randomized, double-blind, placebo-controlled trial suggest that PVB should be considered an effective strategy to reduce opioid requirement and improve pain control for patients undergoing PCNL.

Socioeconomic Disparities in the Acute Management of Stone Disease in the United States.

INTRODUCTION: Patients admitted to the hospital with an acute, noninfected episode of urolithiasis are candidates for medical expulsive therapy, ureteral stent placement, or upfront ureteroscopy (URS). We sought to assess socioeconomic factors influencing treatment decisions in managing urolithiasis and to determine differences in outcomes based on treatment modality. MATERIALS AND METHODS: The Healthcare Cost and Utilization Project State Inpatient Database, State Ambulatory Surgery and Services Database, and State Emergency Department Database for California from 2007 to 2011 and for Florida from 2009 to 2014 were utilized. Patients who were admitted to the hospital with a primary diagnosis of kidney or ureteral stone were identified. The initial treatment modality utilized was assessed and factors that influenced that decision were analyzed. Multivariate logistic regression model was fit to determine factors independently associated with upfront URS. Lastly, outcomes of noninfected patients who underwent stent alone vs URS were compared. RESULTS: We identified 146,199 patients who had an inpatient admission with urolithiasis. Overall, 45% of patients had no intervention at the time of their evaluation. Of the 55% of patients who underwent surgical intervention, 42% underwent stent alone, 44% underwent upfront URS, 1% had a PCN tube placement, 8% underwent extracorporeal shockwave lithotripsy, while 5% underwent PCNL. On multivariate logistic regression model, minorities, younger patients, publicly uninsured patients, more comorbid patients, those admitted on the weekends, and those admitted to an academic institution had significantly lower odds of undergoing upfront URS. Secondary analysis demonstrated clinical and economic advantages of upfront URS vs stent alone in eligible patients. CONCLUSION: Upfront URS is an overlooked procedure that has clinical and cost-saving implications. Unfortunately, minorities, publicly insured patients, and those admitted on the weekend are less likely to undergo upfront URS, a disparity that should be addressed by urologist.

Antepartum nephrolithiasis and the risk of preterm delivery.

Antepartum nephrolithiasis presents a complex clinical scenario which often requires an intervention such as ureteral stent or percutaneous nephrostomy tube (PCNT) placement, especially in the setting of urinary tract infection (UTI). We assess the risk of UTI and preterm labor in the setting of antepartum nephrolithiasis. A retrospective review of an administrative dataset for California and Florida was performed, which included pregnant women admitted for a delivery between 2008 and 2011. Antepartum nephrolithiasis admissions were identified, as were urological intervention (ureteral stent/ureteroscopy) or PCNT placement. Descriptive statistics were performed, as was multivariable logistic regression to identify predictors of UTI and preterm delivery. Of the 2,750,776 deliveries included in this dataset, 3904 (0.14%) were complicated by antepartum nephrolithiasis. 71.4% of these patients were managed conservatively, while 20.6% (n = 803) underwent urological intervention and 8.0% (n = 312) underwent PCNT placement. Preterm delivery rates increased from a baseline of 7.0% for patients without a stone to 9.1% for patients with stones managed conservatively, 11.2% for those undergoing a urologic intervention, and 19.6% for patients who had PCNT placement. On multivariable analysis, conservative management (adjusted odds ratio, aOR 1.3), urologic intervention (aOR 1.5), and PCNT (aOR 2.3) placement each independently increased the risk of preterm delivery (all p < 0.001). Antepartum nephrolithiasis is a condition that affects 1 in 714 women and has been correlated with increased risk of UTI and preterm labor. Intervention with ureteral stent or PCNT placement independently increase these risks, however, receipt of a nephrostomy tube confers the greatest risk of UTI and preterm delivery to the antepartum nephrolithiasis patient.

Metabolic Syndrome Increases Risk of Postoperative Myocardial Infarction Following Percutaneous Nephrolithotomy.

INTRODUCTION: Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for upper tract stone burdens greater than 2 cm. Metabolic syndrome (MetS) is a constellation of conditions (diabetes mellitus, hypertension, dyslipidemia, and obesity) and is a risk factor for nephrolithiasis. Our objective was to investigate adverse cardiovascular outcomes of PCNL in patients with comorbid MetS diagnoses. MATERIALS AND METHODS: Data from the Healthcare Cost and Utilization Project State Inpatient Database for Florida and California were used to identify PCNL patients (ICD9: 55.03, 55.04) between 2007 and 2011. Patients were categorized having 0, 1-2, or 3-4 components of MetS. Postoperative myocardial infarction (MI) and inhospital mortality rate outcomes were identified. Multivariate logistic regression was used to control for patient characteristics (age, race, and primary insurance provider) and medical comorbidities. RESULTS: PCNL was performed on 39,868 patients, of whom 17,932 (45.0%) had no MetS conditions, 19,268 (48.3%) had 1-2 MetS conditions, and 2668 (6.7%) had 3-4 MetS conditions. With increasing MetS conditions, patients had increased incidence of postoperative MI (0: 0.6%; 1-2: 1.0%; 3-4: 1.8%, p < 0.001). On multivariate analysis, the presence of 3-4 MetS comorbidities increased the odds of a postoperative MI (1-2: odds ratio [OR] 1.2, 95% confidence interval [CI] 0.94-1.53, p = 0.147; 3-4: OR 2.2, 95% CI 1.54-3.15, p < 0.001). CONCLUSIONS: MetS patients have an increased risk of MI following PCNL given their pre-existing comorbidities. Routine preoperative cardiac testing may benefit this population before PCNL.

Complications of Recognized and Unrecognized Iatrogenic Ureteral Injury at Time of Hysterectomy: A Population Based Analysis.

PURPOSE: Ureteral injury represents an uncommon but potentially morbid surgical complication. We sought to characterize the complications of iatrogenic ureteral injury and assess the effect of recognized vs delayed recognition on patient outcomes. MATERIALS AND METHODS: Patients who underwent hysterectomy were identified in the Healthcare Cost and Utilization Project California State Inpatient Database for 2007 to 2011. Ureteral injuries were identified and categorized as recognized-diagnosed/repaired on the day of hysterectomy and unrecognized-diagnosed/repaired postoperatively. We assessed the outcomes of 90-day hospital readmission as well as 1-year outcomes of nephrostomy tube placement, urinary fistula, acute renal failure, sepsis and overall mortality. The independent effects of recognized and unrecognized ureteral injuries were determined on multivariate analysis. RESULTS: Ureteral injury occurred in 1,753 of 223,872 patients (0.78%) treated with hysterectomy and it was unrecognized in 1,094 (62.4%). The 90-day readmission rate increased from a baseline of 5.7% to 13.4% and 67.3% after recognized and unrecognized injury, respectively. Nephrostomy tubes were required in 2.3% of recognized and 23.4% of unrecognized ureteral injury cases. Recognized and unrecognized ureteral injuries independently increased the risk of sepsis (aOR 2.0, 95% CI 1.2-3.5 and 11.9, 95% CI 9.9-14.3) and urinary fistula (aOR 5.9, 95% CI 2.2-16 and 124, 95% CI 95.7-160, respectively). During followup unrecognized ureteral injury increased the odds of acute renal insufficiency (aOR 23.8, 95% CI 20.1-28.2) and death (1.4, 95% CI 1.03-1.9, p = 0032). CONCLUSIONS: Iatrogenic ureteral injury increases the risk of hospital readmission and significant, potentially life threatening complications. Unrecognized ureteral injury markedly increases these risks, warranting a high level of suspicion for ureteral injury and a low threshold for diagnostic investigation.

Postoperative Urinary Retention is an Independent Predictor of Short-Term and Long-Term Future Bladder Outlet Procedure in Men.

PURPOSE: Postoperative urinary retention is a common complication across surgical specialties. To our knowledge no literature to date has examined postoperative urinary retention as a predictor of long-term receipt of surgery for bladder outlet obstruction. MATERIALS AND METHODS: We retrospectively reviewed the records of inpatients who underwent nonurological surgery in California between 2008 and 2010. Postoperative urinary retention during the index admission was identified, as was receipt of a bladder outlet procedure (transurethral prostate resection, prostate photoselective vaporization or suprapubic prostatectomy) at a subsequent encounter. Patients were matched using propensity scoring of demographics, comorbidities and surgery type. Adjusted Kaplan-Meier analysis was performed to determine the cumulative incidence of subsequent bladder outlet procedures by patient group, including group 1-age 60 years or greater and postoperative urinary retention, group 2-age 60 years or greater and no postoperative urinary retention, group 3-age less than 60 years and postoperative urinary retention, and group 4-age less than 60 years and no postoperative urinary retention. RESULTS: Of 769,141 eligible male patients postoperative urinary retention developed in 8,051 (1.1%). Following hospital discharge 1,855 patients (0.24%) underwent a bladder outlet procedure. Those treated with a bladder outlet procedure were significantly more likely to have experienced postoperative urinary retention during the index admission (6.3% vs 1.0%, p <0.001). On matched analysis the bladder outlet procedure rate at 3 years was 7.1%, 2.2%, 0.8% and 0.0% in groups 1, 2, 3 and 4, respectively. CONCLUSIONS: In men 60 years old or older postoperative urinary retention identified those with an increased incidence of bladder outlet procedures within 3 years. Men younger than 60 years had a low rate of subsequent bladder outlet procedures regardless of a postoperative urinary retention diagnosis.

Outcomes of percutaneous nephrolithotomy in spinal cord injury patients as compared to a matched cohort.

Spinal cord injury patients are at increased risk of developing nephrolithiasis and may require percutaneous nephrolithotomy for treatment of large stone burdens. Our objective was to compare outcomes of PCNL in SCI patients as compared to a matched cohort of non-SCI patients. Data from the Healthcare Cost and Utilization Project State Inpatient Database for Florida and California were used to identify patients by ICD-9 codes who underwent PCNL between 2007 and 2011. SCI was identified by having a paralysis diagnosis on the chronic comorbidity indicator. One-to-one matching was performed based on age, race, gender, presence of preoperative UTI, and major comorbidities. Of the 39,868 unique patients identified, who underwent PCNL, 1918 (4.81%) were SCI patients. After matching, worse perioperative outcomes in SCI patients were demonstrated. SCI patients had significantly longer length of stay, higher rates of sepsis, and increased minor and moderate complications (p < 0.001). Multivariate analysis demonstrated an independently increased risk of mortality, minor and major complications, pneumonia, sepsis, and length of stay in SCI patients. PCNL in SCI patients is associated with a high complication rate and longer hospital stay even when controlling for presence of preoperative UTI and medical comorbidities. To our knowledge, this is the first study of outcomes of PCNL in a large population of SCI patients. These patients represent a high risk population and strategies to decrease complications need to be developed and implemented.

New modalities for evaluation and surveillance of complex renal cysts.

PURPOSE: The increased use of abdominal imaging has led to more frequent detection of incidental renal cysts. Since the inception of the Bosniak classification system, management of Bosniak I, III and IV cysts has been clearly defined, while evaluation and management of Bosniak II and IIF cysts have remained a clinical dilemma. Discussions of new imaging modalities are becoming increasingly prevalent in the radiological literature. In this context we performed a comprehensive review of the recent literature on complex renal cysts focusing on new imaging modalities, surveillance strategies and biopsy. MATERIALS AND METHODS: We performed a comprehensive literature review of articles published from January 1, 1998 through December 31, 2013 via MEDLINE(®), EMBASE and the Cochrane Collection using a predetermined search strategy. All studies included were performed in humans older than 18 years, were written in English and had an abstract available for review. We grouped studies into 1 of 5 categories, ie computerized tomography, magnetic resonance imaging, ultrasound, biopsy and surveillance. RESULTS: While computerized tomography and magnetic resonance imaging with and without contrast enhancement remain the gold standard to evaluate cystic lesions of the kidney, diffusion-weighted magnetic resonance imaging and contrast enhanced ultrasound have surfaced as new tools for assessment of complex cysts. Comparative effectiveness studies on these new imaging modalities are limited. Image guided biopsy has increasingly been shown to be useful for evaluation of intermediate (Bosniak II and IIF) complex cysts. We found few studies providing guidance on the duration and/or intensity of surveillance required for intermediate complex renal cysts. CONCLUSIONS: Although new and enhanced techniques are in development and may be useful in the future management of complex renal cysts, there is a paucity of data regarding the value of these new techniques. Future research should focus on surveillance of intermediate complex renal cysts, particularly on the ideal frequency and type of imaging required.

Medical management of kidney stones: AUA guideline.

PURPOSE: The purpose of this guideline is to provide a clinical framework for the diagnosis, prevention and follow-up of adult patients with kidney stones based on the best available published literature. MATERIALS AND METHODS: The primary source of evidence for this guideline was the systematic review conducted by the Agency for Healthcare Research and Quality on recurrent nephrolithiasis in adults. To augment and broaden the body of evidence in the AHRQ report, the AUA conducted supplementary searches for articles published from 2007 through 2012 that were systematically reviewed using a methodology developed a priori. In total, these sources yielded 46 studies that were used to form evidence-based guideline statements. In the absence of sufficient evidence, additional statements were developed as Clinical Principles and Expert Opinions. RESULTS: Guideline statements were created to inform clinicians regarding the use of a screening evaluation for first-time and recurrent stone formers, the appropriate initiation of a metabolic evaluation in select patients and recommendations for the initiation and follow-up of medication and/or dietary measures in specific patients. CONCLUSIONS: A variety of medications and dietary measures have been evaluated with greater or less rigor for their efficacy in reducing recurrence rates in stone formers. The guideline statements offered in this document provide a simple, evidence-based approach to identify high-risk or interested stone-forming patients for whom medical and dietary therapy based on metabolic testing and close follow-up is likely to be effective in reducing stone recurrence.