Search

Objectives: Urosepsis currently accounts for half of all post flexible ureterorenoscopy (F-URS) complications, with an incidence of up to 4.3%. It represents a quarter of all septic episodes in adults and 2% of hospital spendings. The primary objective of this study was to define the predictive clinical parameters that increase the risk of urosepsis after F-URS. Subjects/patients (or materials) and methods: This prospective multicentric study evaluated patients who underwent F-URS for calculus between June 2016 and June 2018 in eleven French centers. Clinical, bacteriological, morpho-constitutional stone data, intraoperative information and complications were compared. Risk factors for postoperative urosepsis were identified and analyzed. Results: We included 486 F-URS in 432 patients. The ureter was prepared using a double J stent in 51% of cases, a digital endoscope was used in 56% of patients with a median operative time of 120 min IQR (90–125) and using a sheath in 90% of cases. Postoperative urosepsis was observed in 18 patients (4%) with a median time to onset of 2 days IQR (1–5). The presence of coronary insufficiency: 3 (17%) vs 14 (3%) p = 0.005, a larger stone diameter: 11 cm [9–17] vs 10 cm [8–13] p = 0.02, a positive preoperative urine culture even when treated: 3 (17%) vs 56 (12%) p = 0.04, as well as the final composition of the type IV calculus (carbapatite or struvite) 5 (28%) vs 20 (4%) p < 0.001, were significantly associated with the occurrence of urosepsis. In multivariate analysis, only the presence of a type IV stone (OR = 14.0; p = 0.025) remained significant. Conclusion: Ureteroscopic treatment of a type IV stone (carbapatite or struvite) in a patient should raise concerns about the risk of post-operative urosepsis. When recognized intraoperatively, they should lead to a pyelic urinary sample and prolonged clinical surveillance. [ABSTRACT FROM AUTHOR]

An increased prevalence of vascular calcification (VC) has been reported in kidney stone formers (KSFs), along with an elevated cardiovascular risk. The aim of the current study is to assess whether VC in these patients develops at a younger age and is influenced by stone composition. This single-center, matched case-control study included KSFs with uric acid or calcium oxalate stones (diagnosed based on stone analysis) and age- and sex-matched controls without a history of nephrolithiasis. The prevalence and severity of abdominal aortic calcification (AAC) and bone mineral density (BMD) were compared between KSFs and non-KSFs. In total, 335 patients were investigated: 134 with calcium oxalate stones, 67 with uric acid stones, and 134 controls. Overall, the prevalence of AAC was significantly higher among calcium stone formers than among the controls (67.9% vs. 47%, p = 0.002). In patients under 60 years of age, those with calcium oxalate stones exhibited both a significantly elevated AAC prevalence (61.9% vs. 31.3%, p = 0.016) and severity (94.8 ± 15.4 vs. 30.3 ± 15.95, p = 0.001) compared to the controls. Within the age group of 40–49, osteoporosis was identified only in the KSFs. Multivariate analysis identified age, smoking, and the presence of calcium stones as independent predictors of AAC. This study highlights that VC and osteoporosis occur in KSFs at a younger age than in non-stone-formers, suggesting potential premature VC. Its pathogenesis is intriguing and needs to be elucidated. Early evaluation and intervention may be crucial for mitigating the cardiovascular risk in this population. [ABSTRACT FROM AUTHOR]

Copyright of Die Urologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Proper analysis of urinary stone composition is a cornerstone for diagnosis, targeted treatment and recurrence prevention of urolithiasis. The aim of this study was to determine the composition, frequency and distribution of mixed stones according to gender and age of patients. A total of 42,519 urinary stones from 30,311 men and 12,208 women submitted between January 2007 and December 2020 were studied. Most urinary calculi consisted of two components (50.9%), followed by stones of a single constituent (27.1%) and three-component stones (21.9%), while four-component stones were only rarely identified (0.1%). Among all stones, 49.8% consisted of whewellite (COM), weddellite (COD), and mixtures of COM and COD, 33.8% were pure carbonate apatite (CA) and mixtures of CA with COM and/or COD, while 7.6% were composed of uric acid anhydrous (UAA), uric acid dihydrate (UAD), and mixed UAA and UAD. The remaining 8.8% of calculi were rare single-component stones and rare mixtures of various constituents. The number of stone components was inversely associated with age (p < 0.001). The proportion of men decreased significantly with the number of stone constituents, from 3.01:1 for single-component stones to 1.0:1 for four-component urinary calculi (p < 0.001). The vast majority of urinary calculi consisted of two or more components in varying proportions. While age was inversely associated with the number of stone constituents, the proportion of women increased significantly from single-component to four-component urinary calculi. A significant proportion of mixed stones could present a challenge for diagnosis and targeted recurrence prevention. [ABSTRACT FROM AUTHOR]

Purpose: Bone loss has been found to occur frequently in patients with particular metabolic disorders that are likely associated with certain kidney stone composition. Thus, we compared the bone mineral density (BMD) of patients with different kidney stone compositions. Patients and methods: A total of 204 consecutive patients who exhibited stone formation with calcium oxalate (CaOx), calcium phosphate (CaP), uric acid (UA), and magnesium ammonium phosphate (MAP) underwent 24 h urine test and BMD measurement. BMD was measured by dual X-ray absorptiometry at the lumbar spine (LS) and femoral neck (FN). The Z-score was used to express BMD. A BMD Z-score ≤ − 2 was defined as a diagnostic threshold for bone loss. Results: Amongst the patients, 38 had an LS BMD Z-score of ≤ − 2, but only 2 had FN BMD Z-score of ≤ − 2. The group with an LS BMD Z-score of ≤ − 2 exhibited significantly larger male − female ratio, higher frequency of hypercalciuria and CaP, and lower frequency of MAP than the group with an LS BMD Z-score of > − 2. Reduced LS BMD was most remarkable in the CaP group, followed by the CaOx, UA, and MAP groups. The LS BMD Z-score of hypercalciuric patients was significantly lower than that of normocalciuric patients only in the CaP group. Conclusion: Patients with different kidney stone compositions presented different BMD status. Using this information may facilitate medical decision-making in patients with kidney stone who should undergone BMD earlier. [ABSTRACT FROM AUTHOR]

Urolithiasis is a major public health issue due to its increasing prevalence. The objective of this study was to describe the spectrophotometric profile of upper urinary tract stones (UTS) in Senegal. We conducted a multicenter retrospective study of all patients treated for upper UTS whose chemical composition was analyzed from January 2014 to January 2020 in eight regions of Senegal. Socio-demographic, clinical, paraclinical, and prognosis data were collected and analyzed. Three hundred and thirty-four patients were included in this study with a mean age of 46.3 ± 18.4 years and a sex ratio of 1.38. About one-third of patients (31.1%) had a body mass index > 25 kg/m2 and 74.2% presented with lumbar pain was the main clinical symptom. Calcium oxalate and calcium phosphate stones were the predominant types found, respectively, in 37.7% and 24.5% of patients. Uric acid was the main stone constituent in 18.6% of patients and struvites represented 14.7% of cases. Stones were located in the renal calyces and pelvis in 71.2% of cases. Surgical lithotomy was performed in 62.7% of patients for UTS extraction. Upper UTS are frequent condition in Senegalese with predominance of males and young adults. Calcium and uric acid stones are the main types. Preventive dietary and lifestyle measures are needed to reduce their burden. [ABSTRACT FROM AUTHOR]

Purpose: As part of the management of nephrolithiasis, determination of chemical composition of stones is important. Our objective in this study is to assess urologists' accuracy in making visual, intraoperative determinations of stone composition. Materials and methods: We conducted a REDCap survey asking urologists to predict stone composition based on intraoperative images of 10 different pure-composition kidney stones of 7 different types: calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD), calcium phosphate (CP) apatite, CP brushite, uric acid (UA), struvite (ST) and cystine (CY). To evaluate experience, we examined specific endourologic training, years of experience, and number of ureteroscopy (URS) cases/week. A self-assessment of ability to identify stone composition was also required. Results: With a response rate of 26% (366 completed surveys out of 1,370 deliveries), the overall accuracy of our cohort was 44%. COM, ST, and COD obtained the most successful identification rates (65.9%, 55.7%, and 52.0%, respectively). The most frequent misidentified stones were CP apatite (10.7%) and CY (14.2%). Predictors of increased overall accuracy included self-perceived ability to determine composition and number of ureteroscopies per week, while years of experience did not show a positive correlation. Conclusions: Although endoscopic stone recognition can be an important tool for surgeons, it is not reliable enough to be utilized as a single method for stone identification, suggesting that urologists need to refine their ability to successfully recognize specific stone compositions intraoperatively. [ABSTRACT FROM AUTHOR]

Based on mean Hounsfield Unit (HuMean), we aimed to evaluate the additional use of standard deviation of Hounsfield Unit (HuStd), minimum Hounsfield Unit (HuMin), and maximum Hounsfield Unit (HuMax) in noncontrast computed tomography (NCCT) to evaluate uric acid (UA) stones more accurately. The data of patients who underwent the NCCT examination and infrared spectroscopy in our hospital from August 2017 to December 2021 were analyzed retrospectively. Based on CT scans, the HuMean, HuStd, HuMin, and HuMax of all patients were measured. The patients were divided into groups according to the stone composition. The attenuation value of mixed stones was in the middle of their pure stones. Except for Str, statistically significant differences between UA stones and other pure stones were observed for HuMean, HuStd, HuMin, and HuMax. A moderate correlation was found between HuMean, HuStd, HuMin, and HuMax and UA stones (rs showed −0.585, −0.409, −0.492, and −0.577, respectively). Receiver operator characteristic (ROC) curve showed that the area under the curve (AUC) of HuMean and HuMax were higher than those of HuStd and HuMin (AUC = 0.896, AUC = 0.891 vs. AUC = 0.777, AUC = 0.833). Higher AUC (0.904), specificity (0.899) and positive predictive value (PPV) (0.712) can be obtained by combining HuMean and HuMax in the diagnosis of UA stones. In conclusion, HuMean and HuMax can better predict UA stones than HuStd and HuMin. The combined use of HuMean and HuMax can lead to higher accuracy. [ABSTRACT FROM AUTHOR]

Purpose: Stone composition can provide valuable information for the diagnosis, treatment and recurrence prevention of urolithiasis. The aim of this study was to evaluate the distribution of urinary stone components and the impact of different crystal forms according to gender and age of patients in Germany. Methods: A total of 45,783 urinary stones submitted from 32,512 men and 13,271 women between January 2007 and December 2020 were analyzed by infrared spectroscopy. Only the first calculus obtained per patient was included in the analysis. Results: The most common main stone component was calcium oxalate (CaOx) (71.4%), followed by carbonate apatite (CA) (10.2%) and uric acid (UA) (8.3%). Struvite (2.1%), brushite (1.3%), protein (0.5%) and cystine (0.4%) stones were only rarely diagnosed. CaOx (75%) and UA stones (81%) were more frequently obtained from men than women (p < 0.001). Weddellite (COD) and uric acid dihydrate (UAD) were more common in younger ages than whewellite (COM) and anhydrous uric acid (UAA), respectively, in both men and women. The ratios of COM-to-COD and UAA-to-UAD calculi were approximately 4:1 and 8:1, respectively. The peak of stone occurrence was between the ages of 40 and 59 years. Conclusion: Stone composition is strongly associated with gender and age. The peak incidence of calculi in both women and men was in the most active phase of their working life. The distinction between different crystal forms could provide clues to the activity and mechanisms of lithogenesis. Further research is needed in understanding the causative factors and the process of stone formation. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the epidemiological characteristics of stone components in patients with urolithiasis and analyze the associations between stone components with patients' clinical characteristics. A total of 7126 patients with urolithiasis between July 2005 and June 2020 were retrospectively analyzed. In this research, calcium oxalate stones (74.6%) accounted for the highest proportion, followed by infection stones (11.8%), uric acid (10.6%), brushite (2.0%), and others (1.1%). The change in trend in the composition of urinary stones revealed that the proportion of uric acid declined steadily, while the content of infection stones increased gradually over 15 years. The results also suggested that stone composition was significantly associated with PM2.5, gender, age, BMI, diabetes, hypertension, CCVD, alcohol consumption, albumin, creatinine, WBCHP, leukocyte, urine pH, nitrite and urine culture (P < 0.05). However, there was no significant correlation between stone composition with smoking, WBC and NEU% (P > 0.05). Our study concluded that calcium oxalate represented the highest proportion, followed by infection stones, uric acid, brushite, and others. The proportion of uric acid declined steadily, while the infection stones increased gradually. Furthermore, the factors influencing the formation of urinary calculi are PM2.5, gender, age, BMI, diabetes, hypertension, CCVD, alcohol consumption, albumin, creatinine, WBCHP, leukocyte, urine pH, nitrite and urine culture. Collectively, these results may provide clues to establish effective prevention and management strategies for urinary calculi. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the distribution and dynamic trends in constituents of urinary stones in China. Materials and methods: The composition of 23,182 stones were analyzed and then recorded between January 2011 and December 2019. The characteristics in terms of stone patient's gender, age and calendar year were analyzed. Results: Most stones (22,172, 95.64%) had several crystal components, among which 40.25% (8925/22,172) were mixtures with infection components. Calcium oxalate (CaOx) and uric acid (UA) stones were more commonly encountered in men, but calcium phosphate (CaP), magnesium ammonium phosphate (MAP) and carbonate apatite (CA) stones were more prevalent in women (p < 0.05). In males, the proportion of CaOx stones increased up to the age of 40, but subsequently decreased (p < 0.001). Interestingly, females showed an inverse trend regarding CaOx stones (p < 0.001). The proportion of UA stones increased with age (p < 0.001), and CA stones most frequently were recorded at age 20–49. Over the past 9 years, UA, CA, and MAP stones increased over time, whereas there was a tendency for CaOx stones to decrease (p < 0.05). Conclusions: The scarcity of pure stones and a certain proportion of mixtures with infection stone components (e.g., mixtures of CaOx and CA) suggest that treatment directed against a single stone component is insufficient for effective recurrence prevention. Age and gender were significant determinants of stone composition, and according to the observed chronological trends, it seems that in the future, more UA, CA and MAP stones and fewer CaOx stones may be encountered in the studied population. [ABSTRACT FROM AUTHOR]

Purpose: To propose a size-related definition of stone dust produced by lithotripsy of urinary stones. Methods: Stone dust was defined as particles small enough to adhere to the following criteria: (1) spontaneous floating under 40 cm H2O irrigation pressure; (2) mean sedimentation time of > 2 s through 10 cm saline solution; (3) fully suitable for aspiration through a 3.6 F working channel. Irrigation, sedimentation, and aspiration tests were set up to evaluate each criterion. Primary outcome was particle size limit agreeing with all three criteria. Stone particles with a given size limit (≤ 2 mm, ≤ 1 mm, ≤ 500 µm, ≤ 250 µm, ≤ 125 µm and ≤ 63 µm) were obtained from laser lithotripsy, including samples from prevailing stone types: calcium oxalate monohydrate, calcium oxalate dihydrate, uric acid, carbapatite, struvite, brushite, and cystine. Results: All particles ≤ 250 µm from all stone types were in agreement with all three criteria defining stone dust, except for struvite where size limit for a positive irrigation and sedimentation test was ≤ 125 µm. Conclusion: A size limit of ≤ 250 µm seems to generally adhere to our definition of stone dust, which is based on floating and sedimentation proprieties of stone particles, as well as on the ability to be fully aspirated through the working channel of a flexible ureteroscope. [ABSTRACT FROM AUTHOR]

Purpose of Review: Conventional CT imaging is an excellent tool for the diagnosis of nephrolithiasis however is limited in its ability to detect stone composition. Dual-energy CT (DECT) scans have demonstrated promise in overcoming this limitation. We review the current utility of DECT in nephrolithiasis. Recent Findings: DECT is superior to conventional CT in differentiating uric acid stones from non-uric acid stones, with numerous studies reporting sensitivities and specificities approaching > 95%. Dose reduction protocols incorporating low-dose CT scans are commonly used, providing significantly lower effective radiation doses compared to conventional CT. DECT remains an effective diagnostic tool in patients with large body habitus. Summary: DECT can accurately detect uric acid stones, which can help guide which stones may be suitable to medical dissolution. Further studies evaluating the effectiveness of DECT in guiding management of patients with nephrolithiasis can help to promote its widespread use. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the accuracy of rapid kV-switching single-source dual-energy computed tomography (rsDECT) for prediction of classes of non-uric-acid stones. Materials and methods: Non-uric-acid renal stones retrieved via percutaneous nephrolithotomy were prospectively collected between January 2017 and February 2018 in a single institution. Only stones ≥ 5 mm and with pure composition (i.e., ≥ 80% composed of one component) were included. Stone composition was determined using Fourier Transform Infrared Spectroscopy. The stones were scanned in 32-cm-wide anthropomorphic whole-body phantom using rsDECT. The effective atomic number (Zeff), the attenuation at 40 keV (HU40), 70 keV (HU70), and 140 keV (HU140) virtual monochromatic sets of images as well as the ratios between the attenuations were calculated. Values of stone classes were compared using ANOVA and Mann–Whitney U test. Receiver operating curves and area under curve (AUC) were calculated. A p value < 0.05 was considered statistically significant. Results: The final study sample included 31 stones from 31 patients consisting of 25 (81%) calcium-based, 4 (13%) cystine, and 2 (6%) struvite pure stones. The mean size of the stones was 9.9 ± 2.4 mm. The mean Zeff of the stones was 12.01 ± 0.54 for calcium-based, 11.10 ± 0.68 for struvite, and 10.23 ± 0.75 for cystine stones (p < 0.001). Zeff had the best efficacy to separate different classes of stones. The calculated AUC was 0.947 for Zeff; 0.833 for HU40; 0.880 for HU70; and 0.893 for HU140. Conclusion: Zeff derived from rsDECT has superior performance to HU and attenuation ratios for separation of different classes of non-uric-acid stones. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate whether the size of spontaneously passed stones (SPS) may be associated with clinical parameters. Methods: A search for SPS was conducted in our electronic stone database, comprising data on stones analyzed over the last 33 years at our institution. Adults with upper urinary tract stones were included. Cases with stenotic urinary tract disease or past history of anastomotic urinary tract surgery were excluded. Stone size expressed as maximal stone diameter (MSD) and stone volume (SV) was compared between groups by one-way ANOVA. Logistic regression analyses were performed to identify predictors of MSD ≥ 6 mm. Results: Overall mean MSD and SV for 18,029 SPS was 4.1 mm and 11.5 mm3, respectively, and significantly differed between stone composition groups (p < 0.001). The lowest mean MSD and SV were found for calcium oxalate monohydrate (3.6 mm and 9.0 mm3, respectively) and the highest mean MSD and SV were found for struvite (7.9 mm and 61.0 mm3, respectively). Stone composition and increasing age were found to be independent predictors of MSD ≥ 6 mm (both p < 0.001). Sex differentiation did not contribute as a predictor of MSD ≥ 6 mm. Conclusions: Stone composition and—to a lesser extent—age serve as independent predictors of size of spontaneously passed stones. Of particular importance, large spontaneously passed stones of ≥ 6 mm may be frequently found in cystine, brushite or struvite stone formers, whereas a minority of all calcium oxalate stones exceed that cutoff. Future studies shall evaluate these parameters as possible predictors of spontaneous stone passage. [ABSTRACT FROM AUTHOR]

The aim of the study was to report the characteristics of urolithiasis in Uyghur patients from Xinjiang, China. The composition of stones collected from 1863 patients in the Uyghur region of Xinjiang was analyzed. The median age of patients was 17 years [25th and 75th percentiles: 2, 36]. The stones were delivered by 1299 males (69.7%) and 564 females (30.3%). Calcium oxalate was the predominant stone component in 42.1% of the patients, followed by ammonium urate in 20.6%. Females had formed more stones of magnesium ammonium phosphate 8.9 vs. 5.6% (p = 0.010) and carbonate apatite 6.2 vs. 3.3% (p = 0.004). In contrast uric acid was more common in males than in females; 21.6 vs. 15.1% (p = 0.001). In this series, pediatric patients (age range 0–18) were more likely to present with a stone (51.5%, p < 0.001). Moreover, the largest number of pediatric stones was recorded in children 1–2 years old (37.9%, p < 0.001). The occurrence of ammonium urate stones was extremely high (52.4%) in children with an age below 1 year. There was a downward trend for ammonium urate with age in both children and adults (p for trend < 0.001, respectively). In contrast the frequency of uric acid declined with age in pediatric patients, but increased in adults (p for trend < 0.001, respectively). This study provides a basis for further considerations on the management of Xinjiang Uyghur patients and emphasize the severity of pediatric stone problems. [ABSTRACT FROM AUTHOR]

Purpose: To prospectively examine the diagnostic performance of fast kilovoltage switching dual-energy computed tomography (DECT) in characterization of in vivo renal stone composition compared with postoperative stone analysis.Methods: Consecutive consenting patients scheduled for endoscopic kidney stone surgery in a tertiary referral hospital from June 2015 to January 2016 were enrolled. Patients were preoperatively scanned with single-source, fast kilovoltage switching DECT. Stone compositions were determined regarding the effective atomic number measurements. Results of the stone compositions from DECT were compared to postoperative infrared spectroscopy stone analysis as the standard reference.Results: For the 39 patients enrolled in the study, DECT was able to detect uric acid stone with sensitivity of 88.9% and specificity of 100%. There was 100% positive predictive value, 96.8% negative predictive value, and 97.4% accuracy. For non-contrast CT scan, sensitivity was 88.9%, specificity was 96.7%, positive predictive value was 88.9%, negative predictive value was 96.7%, and accuracy was 94.8%. Of the 39 samples examined, 21 (54%) were single composition, whereas 18 (46%) were combined. Single composition stones were correctly characterized by DECT in 100% (8/8) for uric acid. Whereas the result of uric acid stone containing stone discrimination in mixed composition was not so good with Zeff alone, iodine imaging can compensated this fault.Conclusions: DECT provides excellent accuracy in characterizing uric acid stone compositions. With the addition of iodine image, all of uric acid-containing stones can be determined by the DECT. [ABSTRACT FROM AUTHOR]

The Objective of this study is to analyze the difference in renal stone composition between Uyghur and Han children with urolithiasis in China and possible reasons. From May 2011 to September 2013, we analyzed the stone compositions of 274 Chinese children with urolithiasis, including 151 Uyghur children from Xinjiang Province and 123 Han children from Guangdong Province. All the stone components were determined by Infrared spectroscopy and the main components were recorded. We also evaluated the data, including age, gender and geographic region of the patients. The mean age of Uyghur children was less than Han children (5.3 ± 4.2 vs 8.6 ± 5.7 years, p < 0.001). Calcium oxalate (CaOx) was the main stone composition in both Uyghur (35.1 %) and Han (64.2 %) children, but was more common in Han children ( p < 0.0001). Cystine stone was also more abundant in Han children (8.9 % vs 0.7 %, p = 0.001). While, both uric acid (20.5 % vs 3.3 %, p < 0.0001) and magnesium ammonium phosphate (16.6 % vs 2.5 %, p < 0.0001) stones were more common in Uyghur. Interestingly, the significant differences in stone composition between the two groups were only observed in males. When the pediatric patients were further divided into three age groups which were 0-5, 6-12 and >12, the prevalence of calcium oxalate stones increased with age in both groups and was higher in Han children at each age level. The compositions of urinary stones were significantly different between Uyghur and Han children with urolithiasis, factors such as diet habit, life style, genetic diversity, environmental and medical conditions may all contribute to the variances. [ABSTRACT FROM AUTHOR]

Keywords: Epidemiology; Stone composition; Urolithiasis EN Epidemiology Stone composition Urolithiasis 1083 1084 2 04/12/22 20220401 NES 220401 This comment refers to the article available online at https://doi.org/10.1007/s00345-021-03680-y. Metabolic syndrome and its components (diabetes, dyslipidemia, obesity, hypertension) are so closely related to urinary tract stone disease that urolithiasis has been suggested to be accepted as a metabolic disease [[2]-[4]]. [Extracted from the article]

We investigated the correlation between computed tomography (CT) density of ureteral stones and their mineral composition. A total of 346 patients who underwent ureteroscopic lithotripsy for calculi all fragments of which were acquired at a single institution from 2009 to 2011 were analyzed. The maximum and mean CT densities were measured preoperatively. A mineral analysis revealed calcium oxalate in 203 (58.7 %), mixed calcium oxalate and calcium phosphate in 78 (23.0 %), calcium phosphate in 18 (5.2 %), uric acid in 8 (2.3 %), struvite in 3 (0.9 %), and cysteine in 5 (1.4 %). The mean Hounsfield units (HUs) of the CT density were 1046 HUs in calcium oxalate, 1101 HUs in mixed calcium oxalate and calcium phosphate, 835 HUs in calcium phosphate, 549 HUs in uric acid, 729 HUs in struvite, and 698 HUs in cystine. The HUs in calcium oxalate were significantly higher than those in uric acid ( p < 0.01) and struvite ( p < 0.01). Those in monohydrate stones were significantly higher, compared with dehydrate stones ( p < 0.05). We analyzed the largest number of stones than each published study to correlate their mineral composition and CT density. Calcium component stones showed significantly higher CT densities than other types. [ABSTRACT FROM AUTHOR]

To examine the changes in stone composition from 1990 to 2010. A retrospective review was performed of all renal and ureteral stones submitted from the state of Massachusetts to a single laboratory (Laboratory for Stone Research, Newton, MA) for the years 1990 and 2010. Stone composition was determined by infrared spectroscopy and/or polarizing microscopy. A total of 11,099 stones were evaluated (56.7 % from 1990, 43.3 % from 2010). From 1990 to 2010, the percentage of stones from females (i.e., female/male ratio) increased significantly (29.8 % in 1990 to 39.1 % in 2010, p < 0.001). Among women, from 1990 to 2010, there was a significant increase in stones which were >50 % uric acid (7.6-10.2 %, p < 0.005) and a significant decrease in struvite stones (7.8-3.0 %, p < 0.001). Among women with calcium stones, the % apatite per stone decreased significantly (20.0 vs. 11.7 %, p < 0.001). Among men, there were no changes in stones which were majority uric acid (11.7-10.8 %, p = 0.2). Among men with calcium stones, the % apatite per stone increased significantly (9.8 vs. 12.5 %, p < 0.001). Males also demonstrated a significant increase in both cystine (0.1-0.6 %, p < 0.001) and struvite stones (2.8-3.7 %, p = 0.02). The epidemiology of stone disease continues to evolve and appears to vary according to gender. While some of these findings may be related to population changes in body mass index and obesity, the etiology of others remains unclear. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the utility of the Hounsfield Unit (HU) values as a predictive factor of extracorporeal shock wave lithotripsy outcome for ureteral and renal stones. We also assessed the possibility that HU values could be used to predict stone composition. A retrospective study was performed to measure stone HU values in 260 patients who underwent extracorporeal shock wave lithotripsy (ESWL) for solitary renal and ureteral stones from July 2007 to January 2012. Stone volume, location, skin-to-stone distance, stone HU values, and stone composition were assessed. Success of ESWL was defined as: (1) being stone-free or (2) residual stone fragments <4 mm after 3 months by radiography. Of the 260 assessed patients, 141 (54.2 %) were stone-free, 32 (12.3 %) had residual stone fragments <4 mm (clinically insignificant stone fragments), and 87 (33.5 %) had residual stone fragments ≥4 mm after one round of ESWL. Multivariate analysis revealed that stone location and mean HU were significant predictors of ESWL success. Receiver operating characteristic curves defined cutoff values for predicting treatment outcome. Treatment success rates were significantly higher for stones <815 HU than with stones >815 HU ( P < 0.0265). HU of calcium oxalate and calcium phosphate stones were higher than those of uric acid stones, but we could not differentiate between calcium oxalate monohydrate and calcium oxalate dihydrate stones. Evaluation of stone HU values prior to ESWL can predict treatment outcome and aid in the development of treatment strategies. [ABSTRACT FROM AUTHOR]

Objectives: To describe a cohort of bilateral stone formers with significantly different compositions between renal units. Methods: Patients treated for bilateral nephrolithiasis over a 4-year period (2007-2010) were identified. Stones were categorized by dominant (≥50 %) mineralogical component. Patients with significant compositional differences between renal units (discordant stone formers) were compared to patients with a similar stone type in each kidney. Results: Fifteen of the 59 bilateral stone formers (25.4 %) were discordant stone formers with significant differences in stone composition between renal units. Forty-four of the 59 patients (74.6 %) had the same stone composition on each side. Thirty percent of discordant stones had calcium phosphate as the dominant stone component. Discordant stone formers were younger, had better renal function, and tended to have a larger stone burden ( p < 0.05). Conclusions: A significant minority of bilateral stone formers form a different type of stone in each kidney. Local or micro-environmental etiologies may explain this phenomenon and may also account for failure of preventive therapy in some patients. [ABSTRACT FROM AUTHOR]

Copyright of Der Urologe A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This project sought to test the ability of commercial stone analysis laboratories to correctly analyze urinary stones. Human stone specimens were cleaved into pieces, and the pieces of each specimen were verified as being similar using micro-computed tomography (micro CT), a non-destructive method. Thus, similar specimens from 25 stones were sent to five laboratories, and a sixth piece was kept for analysis in our laboratory using Fourier-transform infrared spectroscopy (FT-IR). The results showed that laboratories were very good at analyzing pure specimens, but with mixed specimens the accuracy and consistency varied. In six stones containing apatite, a mineral easily identified using micro CT, apatite was missed 20% of the time. Struvite content in the specimens was inconsistently reported, with laboratories differing in their reports of the presence of struvite in six of the 25 stones (24%). A mixed stone containing atazanavir was not reported by any of the laboratories as containing that drug. Nomenclature differed among the laboratories, especially with regard to apatite, which was variously reported as hydroxyapatite, carbonate apatite, or as apatite with calcium carbonate. One laboratory reported protein in every stone, while for all others protein was reported in only one stone. We conclude that physicians need to be aware that reports on mixed stones, which represent >90% of all calculi, can be erroneous. It is likely that supplying a greater amount of stone material will assist a laboratory in making a correct analysis of mixed stones. Also, standardization of nomenclature could assist in analysis reproducibility, but this remains to be tested. [ABSTRACT FROM AUTHOR]

Micro-computed tomographic (micro CT) imaging has become an important tool for the study of urinary stones. The method involves the collection of a series of X-ray pictures of the stone as it is rotated, and the internal structure of the stone is computationally reconstructed from these pictures. The entire process takes from 30 min to an hour with present technology. Resulting images of the stone provide unprecedented detail of the mineral composition and its morphological arrangement within the stone. For smaller stones, reconstructions can easily have voxel sizes of <5 μm, making this a truly microscopic view of the stone. The micro CT reconstructions can be viewed with any of a number of existing methods for visualizing the structure of both the surface and internal features of the stone. Because the entire process is non-destructive, traditional analysis methods-such as dissection and spectroscopic examination of portions of the stones-can also be performed. Micro CT adds value to traditional methods by identifying regions of the stone to be analyzed, and also with its ability to scan a cluster of stones or stone fragments at once. Finally, micro CT has become a powerful tool to help investigate events in stone formation that distinguish different kinds of stone disease. [ABSTRACT FROM AUTHOR]

Urolithiasis is a common urologic disease whose prevalence is about 1–20% and increasing throughout the world. The recurrence rate after treatment is more than 50%. Urinary stone analysis is important in determining the possible etiology and the pathophysiology of stone formation. A better understanding of the stone composition may help prevent urinary stone formation. From March 2007 to December 2008, physical analysis of urolithiasis in patients who lived in eastern China for more than 5 years and underwent surgery or shock wave lithotripsy in our hospital or passed their stones spontaneously was carried out using the Fourier transform infrared spectroscopy (FT-IR). Clinical and demographic findings were evaluated and compared with the stone components. Stone analysis was performed in 625 patients. The FT-IR evaluation showed that 234 (37.4%) were pure, and the most frequent was calcium oxalate (33.9%), followed by calcium phosphate (2.7%), and uric acid (0.8%). 391 (62.6%) were mixed stone, calcium oxalate (43.2%) was the most commonly major component, followed by calcium phosphate (16.3%), cystine (1.3%), uric acid (1.1%), and struvite (0.6%). Uric acid ( p = 0.029) was the major component found more frequently in men, while struvite ( p = 0.037) was more frequent in women. Uric acid ( p = 0.031) was more common in lower urinary tract stones, and its formers with the mean age of 55 years were older than those with other components ( p = 0.039). In eastern China, the most commonly found pure stone was calcium oxalate, while the most frequent mixed stone was calcium oxalate and calcium phosphate mixture. Stone location, gender, and age may influence stone component. [ABSTRACT FROM AUTHOR]

Cystine stones are produced by an inherited disorder of the transport of amino acid cystine that results in excess of cystine in the urine (cystinuria). Cystine calculi in urinary tract present a significant problem in patients. We have recorded that cystine calculi are very uncommon in our region. Cystine crystals are unusually identified in the urinary deposits. The problem of recognizing cystine by FTIR as a component in mixture of stones is significant. The problem is compounded by the similarity of wavelengths of cystine with that of whewellite and uric acid. The objective of this paper is to elucidate the problems of identifying cystine in stone analysis and identifying a solution to get over this deficiency. Out of 1,300 urinary stones analysed by ordinary wet chemical methods and infrared spectroscopy, 30 stone samples, which were reported to have cystine peaks in significant numbers, were selected. These samples were powdered, mixed with potassium bromide, pelletized and taken up for FTIR analysis. The wavelength patterns were scrutinized by comparing with the peaks obtained by the reference standards of cystine. Spectra were also obtained from pure cystine. Comparison of spectra with those of whewellite and uric acid was performed. Then the samples were taken for Scanning electron microscopy with elemental distribution analysis X-ray (SEM–EDAX). The samples were made conductive by gold sputtering and were fed into JEOL JSM 35 C SEM machine. Morphology was recorded by taking photographs. Further elemental distribution analysis (EDAX) was carried out to identify the elemental composition. Of the 30 samples taken up for FTIR analysis, all showed spectra identifiable with the reference peaks for cystine. However, when these peaks were compared with those of whewellite and uric acid, all the stone samples showed duplication of peaks for whewellite and uric acid and whewellite. The pure cystine spectra showed identifiable peaks are in the range of 3026, 1618.28, 1485, 846.75 cm−1, etc. (from the standard spectrum of pure cystine). All the analysis findings were correlated with EDAX findings. On doing EDAX, we could separately find out the components present in a mixture. Three stones contained elemental pattern to fit with those of cystine. Even though it is difficult to find out the presence of cystine molecule in FTIR, it is possible to recognize it through EDAX and will be possible to confirm the presence of cystine in mixed urinary stones. [ABSTRACT FROM AUTHOR]

Objective: To analyse the impact of stone composition on stone fragility (fragmentation) and clearance of upper urinary tract stones after shock wave lithotripsy (SWL). Material and methods:Between 1st July 1998 and 31st July 2001, 300 renal and ureteric units of 290 patients (10 being bilateral) underwent SWL for upper urinary tract calculi. The degree of fragmentation was divided into four types: (I) Excellent, (II) Good, (III) Fair and (IV) No fragmentation. Stone composition was done by X-ray diffraction crystallography. A statistical comparison was made between degree of fragmentation, number of shock waves delivered, voltage setting, number of sessions required and requirements of adjuvant procedures according to the stone composition. Results:Stone analysis revealed that 90% of the patients had calcium oxalate stones. Of these 80% were calcium oxalate monohydrate (COM) and 20% calcium oxalate dehydrate (COD). Struvite, apatite and uric acid stones comprised of 6%, 3% and 1% respectively. Type-I fragmentation was achieved up to 63.96%, 50% and 100% in COD, struvite and uric stones respectively as compared to 44.9% and 44.44% for COM and apatite stones. Type-III fragmentation was seen up to 8.79% and 33.3% respectively in COM and apatite as compared to 5.55% or less in other types of the stones suggesting that COM and apatite stones produce larger fragments. The mean number of shock waves, voltage and number of treatments was significantly higher for COM and apatite stones ( p value < 0.005) with a stone free rate of only 65–66% and 65–68% respectively at three months ( p value < 0.001). Similarly the number of adjuvant procedures required in COM alone was more, i.e. 31 as compared to 17 procedures in rest of the other kinds of stones ( p value < 0.05). Conclusion:Stone composition in Indian subcontinent is different from the western world. Fragility of a stone varies with the composition of the stone and affects the therapeutic results. [ABSTRACT FROM AUTHOR]

This epidemiologic study reveals that the occurrence of urolithiasis in the nineteenth century population in Europe is quite similar to that of the twentieth century in Asia. The analogy is demonstrated for age distribution, stone localization, male/female ratio, and stone composition. The distribution of urolithiasis in a low socioeconomic level population is defined by: highest frequency in childhood, more than 40% bladder stones, less than 20% female patients, less than 40% calcium-oxalate stones, and more than 30% uric acid/urate stones. Typical for a population with a high level these characteristics of urolithiasis are: highest frequency among adults, less than 10% bladder stones, more than 25% female patients, more than 60% calcium oxalate stones, and less than 20% uric acid/urate stones. In partially developed countries those values fall in between. [ABSTRACT FROM AUTHOR]

The dietary intakes of 88 renal stone cases and 88 age and sex matched controls were assessed by dietary history using a standardised questionnaire. The stone cases were divided into six subgroups established on the basis of urine biochemistry (calcium, oxalate and uric acid) and stone composition. The average intake of each group was then compared with that of their controls using standard statistical procedures. Cases with idiopathic calcium oxalate stones had significantly lower intakes of dietary fibre, noncellulose polysaccharide, phytate, magnesium, phosphate and thiamine than controls. No significant difference in dietary intake was found between cases with high urinary calcium and uric acid and their respective controls. All cases with a high urinary oxalate had a significantly higher intake of vitamin C than controls. Our results support the belief that dietary intake is an important pre-urinary risk factor of idiopathic renal stone disease. [ABSTRACT FROM AUTHOR]