Pharmacological Management of Ureteral Stent-related Symptoms: A Systematic Review, Bayesian Network Meta-analysis, and Meta-regression.

PURPOSE: Ureteral stents are commonly used for the treatment of ureteral obstruction, most often urolithiasis. Their use may be associated with significant bothersome symptoms and discomfort. Prior studies have examined the effects of various medication regimens on ureteral stent symptoms. This study utilized Bayesian network meta-analysis to analyze all available evidence on the pharmacological management of ureteral stent-related symptoms. MATERIALS AND METHODS: In December 2022 a systematic review was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines on randomized prospective studies on pharmacological management of ureteral stent-related symptoms reporting outcomes using the Ureteral Stent Symptom Questionnaire score on urinary symptoms and pain. The data were analyzed in Review Manager 5.3 and R Studio where a Bayesian network meta-analysis was performed. Treatments were ranked using surface under the cumulative ranking curve and mean difference vs placebo with 95% credible intervals. RESULTS: A total of 26 studies were analyzed. These were used to build networks which were modeled to run 100,000 Markov Chain Montecarlo simulations each. Drug-class analysis revealed the most effective class for each domain: for urinary symptoms, sexual performance, general health, and work performance-combined α-blocker and anticholinergic and phosphodiesterase 5 inhibitors; for pain-combined anticholinergic and pregabalin. The following were the most effective drugs and dosages for specific symptoms: for urinary symptoms-combined silodosin 8 mg+solifenacin 10 mg; for pain-combined silodosin 8 mg+solifenacin 10 mg; for sexual performance-tadalafil 5 mg. Combined silodosin 8 mg+solifenacin 10 mg+tadalafil 5 mg has the best general health scores while solifenacin 10 mg had the best work experience scores. CONCLUSIONS: This network meta-analysis demonstrated that the most effective drug therapy is different for each symptom domain. It is important to consider a patient's chief complaint and domains in order to ascertain the optimal medication regimen for each patient. Further iterations of this analysis can be strengthened by trials that directly compare more of these drugs instead of relying on indirect evidence.

Evaluation of fluid absorption during flexible ureteroscopy in an in vivo porcine model.

OBJECTIVE: To evaluate the relationship between renal pelvis pressure and fluid absorption during ureteroscopy (URS) in a live porcine model. MATERIALS AND METHODS: Flexible URS (fURS) was performed in anaesthetised female Yorkshire pigs. Prior to performing fURS, a 0.3556-mm (0.014″) pressure-sensing guidewire (Comet™, Boston Scientific) was placed to monitor renal pelvis pressure. A simulated fURS procedure was then performed for 1 h. Infusion of irrigation fluid (5% ethanol in saline) at target renal pelvis pressures (37-150 mmHg) was maintained for 1 h using a pressure bag and real-time feedback from the pressure-sensing guidewire. Venous blood was sampled every 10 min. The volume of irrigation fluid absorbed was estimated with established equations. RESULTS: A URS procedure was performed in vivo in 18 porcine kidneys and the volume of irrigation fluid absorbed during the 1 h URS was calculated. The mean (SD) volume of irrigation fluid absorbed after 1 h of simulated URS was 7.6 (5.7), 10.8 (7.1), 26.0 (15.8), and 56.8 (22.3) mL at renal pelvis pressures of 37, 55, 75, and 150 mmHg, respectively. Compared with URS with renal pelvis pressure of 37 mmHg, the volume of fluid absorption was significantly greater at renal pelvis pressures of 75 and 150 mmHg (P = 0.026 and P = 0.047, respectively). In addition, compared with URS with renal pelvis pressure of 37 mmHg, the rate of absorption was significantly greater at renal pelvis pressures of 75 and 150 mmHg (both P < 0.001). CONCLUSION: In this study of an in vivo porcine model of URS, increasing renal pelvis pressures during URS were associated with increases in irrigation fluid absorption and increases in the rate of fluid absorption.

The Uniform grading tooL for flexIble ureterorenoscoPes (TULIP-tool): a Delphi consensus project on standardised evaluation of flexible ureterorenoscopes.

OBJECTIVE: To develop a standardised tool to evaluate flexible ureterorenoscopes (fURS). MATERIALS AND METHODS: A three-stage consensus building approach based on the modified Delphi technique was performed under guidance of a steering group. First, scope- and user-related parameters used to evaluate fURS were identified through a systematic scoping review. Then, the main categories and subcategories were defined, and the expert panel was selected. Finally, a two-step modified Delphi consensus project was conducted to firstly obtain consensus on the relevance and exact definition of each (sub)category necessary to evaluate fURS, and secondly on the evaluation method (setting, used tools and unit of outcome) of those (sub)categories. Consensus was reached at a predefined threshold of 80% high agreement. RESULTS: The panel consisted of 30 experts in the field of endourology. The first step of the modified Delphi consensus project consisted of two questionnaires with a response rate of 97% (n = 29) for both. Consensus was reached for the relevance and definition of six main categories and 12 subcategories. The second step consisted of three questionnaires (response rate of 90%, 97% and 100%, respectively). Consensus was reached on the method of measurement for all (sub)categories. CONCLUSION: This modified Delphi consensus project reached consensus on a standardised grading tool for the evaluation of fURS - The Uniform grading tooL for flexIble ureterorenoscoPes (TULIP) tool. This is a first step in creating uniformity in this field of research to facilitate future comparison of outcomes of the functionality and handling of fURS.

Incidence of Kidney Stones in the United States: The Continuous National Health and Nutrition Examination Survey.

PURPOSE: The incidence of kidney stones in the United States is currently unknown. Here, we assessed the incidence of kidney stones using recent, nationally representative data. MATERIALS AND METHODS: We used the National Health and Nutrition Examination Survey (NHANES) from 2015 to 2018. During this time participants were asked, "Have you ever had a kidney stone?" and "In the past 12 months, have you passed a kidney stone?" Demographics analyzed include age, race, gender, body mass index, history of smoking, diabetes, hypertension, hypercholesterolemia and gout. Multivariable models were used to assess the independent impact of subject characteristics on kidney stone prevalence and incidence. RESULTS: Data were available on 10,521 participants older than age 20. The prevalence of kidney stones was 11.0% (95% CI 10.1-12.0). The 12-month incidence of kidney stones was 2.1% (95% CI 1.5-2.7), or 2,054 stones per 100,000 adults. We identified significant relationships between stone incidence and subject age, body mass index, race and history of hypertension. CONCLUSIONS: Here we find a substantially higher 12-month incidence of kidney stones than previous reports. We also validate known risk factors for stone prevalence as associated with incidence. The remarkable incidence and prevalence of stones is concerning and has implications for disease prevention and allocation of medical resources.

Stent duration and increased pain in the hours after ureteral stent removal.

INTRODUCTION To assess the relationship between pain after ureteral stent removal and patient and procedural factors. MATERIALS AND METHODS: A validated survey designed to assess the relationship between quality of life and treatment decisions in kidney stone disease was randomly distributed to patients with a history of a ureteral stent in seven medical centers across North America participating in an endourology research collaborative between July 2016 and June 2018. The primary outcome was increased pain after ureteral stent removal. Statistical analyses were performed using Chi-square and multiple logistic regression. RESULTS: A total of 327 surveys were analyzed. Twenty seven percent of patients reported increased pain in the hours after ureteral stent removal. Patients with a stent ≤ 7 days were significantly more likely to experience pain after stent removal compared to those with a stent > 7 days (33.3% versus 22.8%, p = 0.04). Female gender (OR: 2.41, 95% CI: 1.42-4.10) was associated with increased pain after stent removal, while increasing age was inversely associated (OR: 0.52, 95% CI: 0.36-0.74). After adjustment, patients with a stent > 7 days were significantly less likely to report pain in the hours after removal (OR: 0.59, 95% CI: 0.35-0.99). CONCLUSIONS: Approximately one in four patients will experience increased pain after ureteral stent removal. Female patients, younger patients, and patients with a stent ≤ 7 days were more likely to experience an increase in pain immediately following stent removal. Understanding factors associated with post-stent removal pain may be helpful in counseling patients at high risk stent removal morbidity.

Kidney Stones and Risk of Narcotic Use.

PURPOSE: The rise in opioid related deaths and addiction has been linked to physician prescribing. Opioids are commonly prescribed to patients with renal colic due to nephrolithiasis. The aim of this study was to describe the relationship between nephrolithiasis and opioid use in the United States. MATERIALS AND METHODS: Using the NHANES (National Health and Nutrition Examination Survey) we analyzed the relationship between a self-reported history of kidney stones and current opioid use in a nationally representative sample. RESULTS: Current opioid use was significantly greater among those who did vs did not report a history of kidney stones (10.9%, 95% CI 9.1-12.9 vs 6.1%, 95% CI 5.4-6.8). The prevalence of opioid use increased with the number of kidney stones passed, reaching 13.7% (95% CI 11.1-16.9) in subjects who had passed 2 or more stones (p <0.001). On multivariable logistic regression analysis adjusting for age, gender, smoking status, number of health care visits in the last year and comorbid conditions nephrolithiasis was independently associated with opioid based medication use (OR 1.27, 95% CI 1.07-1.49, p = 0.006). CONCLUSIONS: The association between a history of kidney stones and current narcotic use suggests that nephrolithiasis may be a risk factor for long-term opioid use. While this study is limited by the cross-sectional design and the absence of detailed stone histories, it adds to the evidence that altering pain management strategies may be beneficial in this population.

Use of the Quick Sequential Organ Failure Assessment Score for Prediction of Intensive Care Unit Admission Due to Septic Shock after Percutaneous Nephrolithotomy: A Multicenter Study.

PURPOSE: Recent studies have demonstrated that quick sequential organ failure assessment criteria may be more accurate than systemic inflammatory response syndrome criteria to predict postoperative sepsis. In this study we evaluated the ability of these 2 criteria to predict septic shock after percutaneous nephrolithotomy. MATERIALS AND METHODS: We performed a retrospective multicenter study in 320 patients who underwent percutaneous nephrolithotomy at a total of 8 institutions. The criteria for quick sequential organ failure assessment and systemic inflammatory response syndrome were collected 24 hours postoperatively. The study primary outcome was postoperative septic shock. Secondary outcomes included 30 and 90-day emergency department visits, and the hospital readmission rate. RESULTS: Three of the 320 patients (0.9%) met the criteria for postoperative septic shock. These 3 patients had positive criteria for quick sequential organ failure assessment and systemic inflammatory response syndrome. Of the entire cohort 23 patients (7%) met quick sequential organ failure assessment criteria and 103 (32%) met systemic inflammatory response syndrome criteria. Specificity for postoperative sepsis was significantly higher for quick sequential organ failure assessment than for systemic inflammatory response syndrome (93.3% vs 68.4%, McNemar test p <0.001). The positive predictive value was 13% for quick sequential organ failure assessment criteria and 2.9% for systemic inflammatory response syndrome criteria. On multivariate logistic regression systemic inflammatory response syndrome criteria significantly predicted an increased probability of the patient receiving a transfusion (ß = 1.234, p <0.001). Positive quick sequential organ failure assessment criteria significantly predicted an increased probability of an emergency department visit within 30 days (ß = 1.495, p <0.05), operative complications (ß = 1.811, p <0.001) and transfusions (p <0.001). The main limitation of the study is that it was retrospective. CONCLUSIONS: Quick sequential organ failure assessment criteria were superior to systemic inflammatory response syndrome criteria to predict infectious complications after percutaneous nephrolithotomy.

Dual-Source Dual-Energy CT in Detection and Characterization of Urinary Stones in Patients With Large Body Habitus: Observations in a Large Cohort.

OBJECTIVE: The objective of our study was to investigate the impact of large body habitus on dual-energy CT (DECT) image quality and stone characterization. MATERIALS AND METHODS: We retrospectively included 105 consecutive patients with large body habitus (> 90 kg) who underwent stone protocol DECT between 2015 and 2017. The evaluation of DECT datasets was performed for image quality assessment based on European Guidelines on Quality Criteria for Computed Tomography and for determination of stone composition (i.e., uric acid vs non-uric acid). Correlation between DECT characterization and crystallography results was performed when available. The cohort was divided into two groups on the basis of body weight (≤ 104 kg and > 104 kg), and comparisons were made for image quality and stone characterization. RESULTS: One hundred ninety-seven urinary tract calculi (size: mean ± SD, 5.7 ± 5.3 mm; range, 1.4-56 mm) were detected in 73% (79/108) of examinations in 105 patients (weight: mean ± SD, 104.0 ± 12.7 kg; range, 91-163 kg). The overall mean image quality score of blended images and color maps was 3.7 and 3.9, respectively, and the effective dual-energy FOV limitation did not hamper stone characterization. The diagnostic acceptability scores of blended images and color maps were slightly lower in patients weighing > 104 kg than in patients ≤ 104 kg (mean scores [highest score, 4 points]: blended images, 3.62 vs 3.82 [p = 0.0314]; color maps, 3.75 vs 3.98 [p = 0.0034]), but the scores were within acceptable range. Stone characterization as uric acid versus non-uric acid was achieved in 80% (158/197) of calculi (size: mean ± SD, 6.4 ± 5.7 mm; range, 1.6-56 mm), and DECT stone characterization was (95.6%) accurate with reference to crystallography. Twenty percent (39/197) of calculi could not be characterized on DECT, and these calculi were significantly smaller in size (size: mean ± SD, 2.8 ± 1.4 mm; range, 1.4-8.2 mm; p < 0.001) than those that could be characterized. The mean size of uncharacterized calculi was slightly larger in patients weighing > 104 kg (3.3 ± 1.6 mm) than in those weighing ≤ 104 kg (2.2 ± 0.6 mm). CONCLUSION: In patients with large body habitus, dual-source DECT provides acceptable image quality and allows characterization of almost all clinically significant calculi.

Cessation of Ureteral Colic Does Not Necessarily Mean that a Ureteral Stone Has Been Expelled.

PURPOSE: We evaluated whether cessation of renal colic is consistent with an expelled ureteral stone or whether imaging may be indicated even in the absence of symptoms. MATERIALS AND METHODS: We performed a retrospective study of patients who presented to our institution with acute renal colic and ureteral stone, and were subsequently evaluated at a followup visit where they reported complete cessation of pain for at least 72 hours. RESULTS: Study inclusion criteria were met by 52 patients, who reported no pain for at least 72 hours at the time of the followup visit. A persistent ureteral stone was demonstrated in 14 of the 52 patients (26%) although they denied any associated symptoms. Multivariate logistic regression did not show an association between stone size or location and the likelihood of passage in this cohort. CONCLUSIONS: Cessation of pain was associated with ureteral stone passage in almost 75% of this study cohort but 26% of patients still had persistent ureteral stones. We recommend routine followup imaging in all patients with ureteral stones to document stone passage and avoid the risks of silent ureteral obstruction.

Dusting versus Basketing during Ureteroscopy-Which Technique is More Efficacious? A Prospective Multicenter Trial from the EDGE Research Consortium.

PURPOSE: There is scant evidence in the literature to support dusting vs active basket extraction during ureteroscopy for kidney stones. We prospectively evaluated and followed patients to determine which modality produced a higher stone-free rate with the fewest complications. MATERIALS AND METHODS: Members of the Endourologic Disease Group for Excellence research consortium prospectively enrolled patients with a renal stone burden ranging from 5 to 20 mm in this study. A holmium laser was used and all patients were stented postoperatively. Ureteral access sheaths were used in 100% of basketing cases while sheaths were optional when dusting. The primary study outcome was the stone-free rate at 6 weeks as determined by x-ray and ultrasound. RESULTS: A total of 84 and 75 patients were enrolled in the basketing and dusting arms, respectively. Stones in the dusting group were significantly larger (mean ± SD stone area 96.1 ± 65.3 vs 63.3 ± 46.0 mm2, p <0.001). The stone-free rate was significantly higher in the basketing group on univariate analysis (74.3% vs 58.2%, p = 0.04) but not on multivariate analysis (1.9 OR, 95% CI 0.9-4.3, p = 0.11). In patients who underwent a basketing procedure operative time was 37.7 minutes longer than in those treated with a dusting procedure (95% CI 23.8-51.7, p <0.001). There was no statistically significant difference in complication rates, hospital readmissions or additional procedures between the groups. CONCLUSIONS: The stone-free rate was higher for active basket retrieval of fragments at short-term followup on univariate analysis but not on multivariate analysis. There was no difference in postoperative complications or procedures. The 2 techniques should be in the armamentarium of the urologist.

Assessment of readability, quality and popularity of online information on ureteral stents.

OBJECTIVE: To evaluate the quality and readability of online information on ureteral stents. METHODS: Google.com was queried using the search terms "ureteric stent", "ureteral stent", "double J stent" and, "Kidney stent" derived from Google AdWords. Website popularity was determined using Google Rank and the Alexa tool. Website quality assessment was performed using the following criteria: Journal of the American Medical Association (JAMA) benchmarks, Health on the Net (HON) criteria, and a customized DISCERN questionnaire. The customized DISCERN questionnaire was developed by combining the short validated DISCERN questionnaire with additional stent-specific items including definition, placement, complications, limitations, removal and "when to seek help". Scores related to stent items were considered as the "stent score" (SS). Readability was evaluated using five readability tests. RESULTS: Thirty-two websites were included. The mean customized DISCERN score and "stent score" were 27.1 ± 7.1 (maximum possible score = 59) and 14.6 ± 3.8 (maximum possible score = 24), respectively. A minority of websites adequately addressed "stent removal" and "when to seek medical attention". Only two websites (6.3%) had HON certification (drugs.com, radiologyinfo.org) and only one website (3.3%) met all JAMA criteria (bradyurology.blogspot.com). Readability level was higher than the American Medical Association recommendation of sixth-grade level for more than 75% of the websites. There was no correlation between Google rank, Alexa rank, and the quality scores (P > 0.05). DISCUSSION: Among the 32 most popular websites on the topic of ureteral stents, online information was highly variable. The readability of many of the websites was far higher than standard recommendations and the online information was questionable in many cases. These findings suggest a need for improved online resources in order to better educate patients about ureteral stents and also should inform physicians that popular websites may have incomplete information.

Changing incidence of factitious renal stone disease
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PURPOSE: We sought to describe patterns of factitious urinary stone submission over time by investigating a contemporary stone analysis database and comparing two distinct time points. MATERIALS AND METHODS: We retrospectively reviewed a single stone analysis lab database at two time points, 1990 and 2010, and compared total incidence of factitious stone submission, as well as gender patterns and type of factitious stone submitted. RESULTS: A total of 27,014 stones were analyzed, 16,216 (60%) from 1990 and 10,798 (40%) from 2010 with a decrease in total incidence from 2.6% (428/16,216) in 1990 to 1.2% (131/10,798) in 2010 (p < 0.001). In 1990, women were significantly more likely to submit a factitious stone (RR 1.5, 95% CI 1.4 - 1.7, p < 0.001), while in 2010 there was no gender difference (RR 0.9, 95% CI 0.8 - 1.03, p < 0.05). Plant material and geologic material represented the most common factitious stone types respectively, in both 1990 and 2010. CONCLUSION: In the largest contemporary review of spurious urinary stones, we find a decreased incidence and increased gender equivalence of factitious urinary stones in 2010 compared to 1990.
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Predicting ureteral stones in emergency department patients with flank pain: an external validation of the STONE score.

PURPOSE: The ability to objectively predict which emergency department patients are likely to have a ureteral stone may aid in cost-effectiveness and patient-centered diagnostic imaging decisions. We performed an external validation of the STONE score, a clinical prediction rule for the presence of uncomplicated ureteral stones in emergency department patients developed at Yale University School of Medicine. METHODS: Five hundred thirty-six (536) consecutive patients evaluated in an urban tertiary care emergency department for the possible diagnosis of ureteral stone were retrospectively reviewed. The STONE score uses five factors (gender, duration of pain, race, nausea/vomiting, erythrocytes on urine dipstick) to categorize patients into low, medium, and high probability of having a ureteral stone. The total STONE score risk is 0-13 and divided into three groups: low risk = 0-5, moderate risk = 6-9, and high risk = 10-13. RESULTS: Of the 536 patients evaluated for suspected ureteral stone, 257 (47.8 %) had a ureteral stone. Mean patient age was 45.9 years (SD 16.3), and gender distribution was 43.9 % female and 56.1 % male. Distribution of STONE score risk was 24.1 % low, 48.1 % moderate, and 27.7 % high. Diagnosis of ureteral stone by STONE score risk was 14 % for low-risk group, 48.3 % for moderate-risk group, and 75.8 % for high-risk group. This distribution is consistent with internal validation at Yale University School of Medicine, where values were 8.3-9.2 % for low risk, 51.3-51.6 % for moderate risk, and 88.6-89.6 % for high risk. CONCLUSIONS: Our study validates the use of the STONE clinical score to categorize patients as low, moderate, and high risk for ureteral stone. This could help guide development of clinical decision rules for diagnostic studies and imaging in the future.

Can ureteral stones cause pain without causing hydronephrosis?

INTRODUCTION: While computerized tomography (CT) is the gold standard for diagnosis of ureterolithiasis, ultrasound is a less costly and radiation-free alternative which is commonly used to evaluate patients with ureteral colic. The purpose of this study was to evaluate the frequency with which patients with ureteral stones and renal colic demonstrate hydronephrosis in order to better understand the evaluation of these patients. METHODS: Two hundred and forty-eight consecutive patients presenting with ureteral colic and diagnosed with a single unilateral ureteral stone on CT scan in an urban tertiary care emergency department were retrospectively reviewed. Radiology reports were reviewed for stone size, diagnosis, and degree of hydronephrosis. RESULTS: Of the 248 patients evaluated for suspected ureteral stone, 221 (89.1 %) demonstrated any hydronephrosis, while 27 (10.9 %) did not. Hydronephrosis grade, available in 194 patients, was as follows: mild-70.6 %, moderate-27.8 %, and severe-1.5 %. Mean patient age was 47.0 years (SD 15.5), gender distribution was 35.9 % female and 64.1 % male, and mean stone axial diameter was 4.1 mm (SD 2.4). Stone location was as follows: ureteropelvic junction-4.1 %, proximal ureter-21 %, distal ureter-24.9 %, and ureterovesical junction-47.1 %. Axial stone diameter and coronal length (craniocaudal) were both significant predictors of degree of hydronephrosis (ANOVA, p < 0.001 for both). Age (ANOVA, p = NS), stone location (Chi square, p = NS), and gender (Chi square, p = NS) were not associated with degree of hydronephrosis. CONCLUSIONS: In patients with ureteral stones and colic, nearly 11 % do not demonstrate any hydronephrosis and a majority (nearly 71 %) will demonstrate only mild hydronephrosis. Stone diameter appears to be related to degree of hydronephrosis, whereas age, gender, and stone location are not. The lower incidence of hydronephrosis for small stones causing renal colic may explain the lower diagnostic accuracy of ultrasound when compared to CT for detecting ureteral stones.

Hounsfield density of renal papillae in stone formers: analysis based on stone composition.

PURPOSE: We examined renal papillary Hounsfield density in stone formers with all common stone subtypes to further understand the pathophysiology of stone formation. MATERIALS AND METHODS: Using computerized tomography we measured the Hounsfield density of a 0.2 cm(2) renal papillary area in patients with a single renal calyceal stone. Results were compared with those in patients without a nephrolithiasis history who served as controls. Stone composition was determined by stone passage or extraction during endoscopic procedures using infrared spectroscopy and polarized microscopy. We measured the Hounsfield density of the stone bearing calyx and of a single calyx from the upper, middle and lower poles of each kidney. RESULTS: Mean ± SD renal papillary Hounsfield density in controls was 36.2 ± 4.0 HU. In patients with stones Hounsfield density was significantly greater than in controls in stone bearing calyces, nonstone bearing calyces in the affected kidney and calyces in the contralateral nonstone bearing kidney for all stone composition subtypes (range 48.4 to 61.3 HU, each p <0.001). CONCLUSIONS: Patients with kidney stones regardless of composition showed the unique radiographic characteristic of increased renal papillary Hounsfield density. This was true for all calyces and for each kidney in all stone formers with a single renal calyceal stone. This radiographic evidence supports the role of renal papillary deposits or plaques in the pathophysiology of stone formation.

Compliance with American Urological Association Guidelines for Post-Percutaneous Nephrolithotomy Antibiotics Does Not Appear to Increase Rates of Infection.

PURPOSE: We compared infection rates after percutaneous nephrolithotomy in a group of patients without a history of infection or struvite calculi who received 24 hours or less of antibiotics postoperatively (ie compliance with AUA guidelines) vs a group that received 5 to 7 days of antibiotics postoperatively. MATERIALS AND METHODS: We retrospectively reviewed the records of consecutive percutaneous nephrolithotomy procedures in patients without a history of urinary tract infection. Group 1 received 24 hours or less of antibiotics postoperatively and group 2 received a mean of 6 days of antibiotics postoperatively. RESULTS: A total of 52 patients in group 1 (24 hours or less of antibiotics) and 30 in group 2 (mean 6 days of antibiotics) met study inclusion criteria. In 5 group 1 patients (9.6%) fever developed within 72 hours of percutaneous nephrolithotomy but none demonstrated bacteriuria or bacteremia on cultures. No patient in group 1 was treated for urinary tract infection on postoperative days 3 to 14. In 4 group 2 patients (13.3%) fever developed within 72 hours of percutaneous nephrolithotomy. A single patient showed bacteriuria (less than 10,000 cfu mixed gram-positive bacteria) on culture while no patient demonstrated bacteremia. No patient in group 2 was treated for urinary tract infection on postoperative days 3 to 14. There was no difference in stone-free rates or the need for additional procedures between the 2 groups. CONCLUSIONS: In this pilot series compliance with AUA guidelines for antibiotic prophylaxis did not result in higher rates of infection than in a comparable group of 30 patients who received approximately 6 days of antibiotics postoperatively.

A prospective, multi-institutional study of flexible ureteroscopy for proximal ureteral stones smaller than 2 cm.

PURPOSE: Flexible ureteroscopy is rapidly becoming a first line therapy for many patients with renal and ureteral stones. However, current understanding of treatment outcomes in patients with isolated proximal ureteral stones is limited. Therefore, we performed a prospective, multi-institutional study of ureteroscopic management of proximal ureteral stones smaller than 2 cm to better define clinical outcomes associated with this approach. MATERIALS AND METHODS: Adult patients with proximal ureteral calculi smaller than 2 cm were prospectively identified. Patients with concomitant ipsilateral renal calculi or prior ureteral stenting were excluded from study. Flexible ureteroscopy, holmium laser lithotripsy and ureteral stent placement was performed. Ureteral access sheath use, laser settings and other details of perioperative and postoperative management were based on individual surgeon preference. Stone clearance was determined by the results of renal ultrasound and plain x-ray of the kidneys, ureters and bladder 4 to 6 weeks postoperatively. RESULTS: Of 71 patients 44 (62%) were male and 27 (38%) were female. Mean age was 48.2 years. ASA(®) score was 1 in 12 cases (16%), 2 in 41 (58%), 3 in 16 (23%) and 4 in 2 (3%). Mean body mass index was 31.8 kg/m(2), mean stone size was 7.4 mm (range 5 to 15) and mean operative time was 60.3 minutes (range 15 to 148). Intraoperative complications occurred in 2 patients (2.8%), including mild ureteral trauma. Postoperative complications developed in 6 patients (8.7%), including urinary tract infection in 3, urinary retention in 2 and flash pulmonary edema in 1. The stone-free rate was 95% and for stones smaller than 1 cm it was 100%. CONCLUSIONS: Flexible ureteroscopy is associated with excellent clinical outcomes and acceptable morbidity when applied to patients with proximal ureteral stones smaller than 2 cm.

Relationship between C-reactive protein and kidney stone prevalence.

PURPOSE: We evaluated the relationship between serum C-reactive protein and the lifetime kidney stone prevalence. MATERIALS AND METHODS: We performed a cross-sectional study of participants from the Continuous National Health and Nutrition Examination Survey (NHANES) from 2007 to 2008 and 2008 to 2009. Data were available on 11,033 participants. RESULTS: On univariate analysis we noted a strong correlation between C-reactive protein quintile and kidney stone history. After adjusting for known confounders multivariate logistic regression revealed a significant relationship between C-reactive protein and the lifetime prevalence of kidney stones in younger individuals (age 20 to 39 years, p for trend = 0.002). In individuals 20 to 39 years old the lifetime prevalence of kidney stones increased with increasing C-reactive protein quintile (p = 0.002 for trend), specifically, those in the third quintile (OR 3.86, 95% CI 1.07-13.88, p = 0.04) and the fifth quintile (OR 3.85, 95% CI 1.46-10.17, p = 0.009). The fourth quintile of C-reactive protein approached statistical significance (OR 2.56, 95% CI 0.96-6.81, p = 0.059). The relationship between C-reactive protein and kidney stone history was not significant in the older age groups (40 to 59 and 60 years or greater). CONCLUSIONS: There exists a significant relationship between serum C-reactive protein and self-reported kidney stones in younger individuals. This may shed light on potential mechanisms of stone formation in this age group and help gain a better understanding of stone risk mediators. Further studies are needed to understand the mechanisms underlying these epidemiological findings.

Risk of chronic and end stage kidney disease in patients with nephrolithiasis.

PURPOSE: We examine kidney stone disease as a potential risk factor for chronic kidney disease, end stage kidney disease and treatment with dialysis. MATERIALS AND METHODS: The NHANES (National Health and Nutrition Examination Survey) 2007-2010 database was interrogated for patients with a history of kidney stones. Demographics and comorbid conditions including age, gender, body mass index, diabetes, hemoglobin A1c, hypertension, gout and smoking were also assessed. Multivariate analysis adjusting for patient demographics and comorbidities was performed to assess differences in the prevalence of chronic kidney disease and treatment with dialysis between the 2 groups. History of nephrolithiasis was assessed with the question, "Have you ever had kidney stones?" Chronic kidney disease was defined as an estimated glomerular filtration rate of less than 60 ml/minute/1.73 m(2) and/or a urinary albumin-to-creatinine ratio greater than 30 mg/gm. Statistical calculations were performed using Stata® software with determinations of p values and 95% CI where appropriate. RESULTS: The study included an analysis of 5,971 NHANES participants for whom data on chronic kidney disease and kidney stones were available, of whom 521 reported a history of kidney stones. On multivariate analysis a history of kidney stones was associated with chronic kidney disease and treatment with dialysis (OR 1.50, 1.10-2.04, p = 0.013 and OR 2.37, 1.13-4.96, p = 0.025, respectively). This difference appeared to be driven by women, where a history of kidney stones was associated with a higher prevalence of chronic kidney disease (OR 1.76, 1.13-2.763, p = 0.016) and treatment with dialysis (OR 3.26, 1.48-7.16, p = 0.004). There was not a significant association between kidney stone history and chronic kidney disease or treatment with dialysis in men. CONCLUSIONS: Kidney stone history is associated with an increased risk of chronic kidney disease and treatment with dialysis among women even after adjusting for comorbid conditions. Large scale prospective studies are needed to further characterize the relationship between nephrolithiasis and chronic kidney disease.