Stone Analysis Research Articles

PD21-01 OUTCOMES AND RATES OF DISSOLUTION THERAPY FOR URIC ACID STONES

You have accessJournal of UrologyStone Disease: Medical & Dietary Therapy (PD21)1 Sep 2021PD21-01 OUTCOMES AND RATES OF DISSOLUTION THERAPY FOR URIC ACID STONES Jonathan Moore, Amihay Nevo, Saif Salih, Haidar Abdul-Muhsin, Mira Keddis, Karen Stern, and Mitchell Humphreys Jonathan MooreJonathan Moore More articles by this author , Amihay NevoAmihay Nevo More articles by this author , Saif SalihSaif Salih More articles by this author , Haidar Abdul-MuhsinHaidar Abdul-Muhsin More articles by this author , Mira KeddisMira Keddis More articles by this author , Karen SternKaren Stern More articles by this author , and Mitchell HumphreysMitchell Humphreys More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002010.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: To describe the outcomes and quantify the rate of uric acid stone medical dissolution therapy using automated, software-generated stone volume measurements METHODS: A sample of patients treated with oral dissolution therapy was reviewed from a single institution between 2008 and 2019. Baseline patient demographics, metabolic urine testing and stone characteristics were collected. CT scan images were evaluated using the quantitative Stone Analysis Software (qSAS) to obtain total stone volume (TSV), maximum diameter (MD) and stone number. Rate of dissolution using TSV was calculated over the treatment period. RESULTS: A total of 27 patients were started on oral dissolution therapy, corrected for renal function. After mean treatment duration of 180 days (range 41-531), 16 patients failed treatment due to intolerance (2), lack of pH change (2), compliance with medication (6) and resistance of stone (6), resulting in surgical therapy. Twenty stones in 11 patients showed complete (CD) or partial dissolution (PD) and were analyzed with the qSAS software. Compared to those who failed treatment, CD and PD patients had lower 24 h urinary uric acid (0.6 vs. 1.7 g/day, p=0.025) and higher treatment urine pH (6.8 vs 5.9, p<0.001). Pre-treatment stone burden had a MD 16.6 mm (range 4.5-40.4), TSV 1014 mm3 (range 27-4939) and attenuation 354.8 HU (range 22-455). Thirteen (65%) stones showed CD on imaging. Time to CD was 167.6 days (SD 82.9, range 41-312). CD patients had a significantly lower HU than PD (291.8 vs. 392 HU, p=0.005). Rate of change for responders was 4.73 mm3 or 0.6% of TSV per day. Time to dissolution of 50% of stone volume based on TSV was 86 days (12.30 weeks). MD overestimated the time to 50% of stone volume by 72.1 days (10.3 weeks). CONCLUSIONS: Use of software-calculated TSV is an effective method of measuring uric acid stone response to oral alkalization therapy. Stone volume decreased by 50% after 12.3 weeks of treatment. Further studies with a larger sample are needed to confirm if this can be used to guide surveillance schedules for dissolution therapy. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e373-e373 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jonathan Moore More articles by this author Amihay Nevo More articles by this author Saif Salih More articles by this author Haidar Abdul-Muhsin More articles by this author Mira Keddis More articles by this author Karen Stern More articles by this author Mitchell Humphreys More articles by this author Expand All Advertisement Loading ...

MP54-14 A PREOPERATIVE PREDICTIVE SCORE FOR URIC ACID KIDNEY STONES

You have accessJournal of UrologyStone Disease: Epidemiology & Evaluation II (MP54)1 Sep 2021MP54-14 A PREOPERATIVE PREDICTIVE SCORE FOR URIC ACID KIDNEY STONES Mario Basulto-Martínez, Silvia Proietti, Maria Pia Pavia, Luis Rico, Yuyi Yeow, Juan Pablo Flores-Tapia, Antonio Esqueda-Mendoza, Franco Gaboardi, and Guido Giusti Mario Basulto-MartínezMario Basulto-Martínez More articles by this author , Silvia ProiettiSilvia Proietti More articles by this author , Maria Pia PaviaMaria Pia Pavia More articles by this author , Luis RicoLuis Rico More articles by this author , Yuyi YeowYuyi Yeow More articles by this author , Juan Pablo Flores-TapiaJuan Pablo Flores-Tapia More articles by this author , Antonio Esqueda-MendozaAntonio Esqueda-Mendoza More articles by this author , Franco GaboardiFranco Gaboardi More articles by this author , and Guido GiustiGuido Giusti More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002084.14AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The stone analysis composition is paramount for patients' follow-up and prevention but is only available after surgery. Uric acid calculi (UAC) account for up to 15%. Recent evidence points that UAC <2 cm can be first treated by alkalinizing therapy with good results. Furthermore, alkalinizing larger UAC, may decrease the stone burden and therefore improve the chance of achieving a stone-free rate in a further surgical procedure. We aimed to create a preoperative score for predicting UAC. METHODS: Patients who underwent kidney stones surgery from to March 2018 to March 2019 with available preoperative abdominal non-contrast computed tomography (CT) scan and stone analysis composition were included and clinical data was obtained. Mean Hounsfield Units (HU) and standard deviation from the stone density (SDSD) were calculated from CT scans, as computed by growing Regions of Interest using OsiriX DICOM viewer Software. The stone analysis composition was carried out by infrared spectroscopy. Stones >80% of uric acid weredichotomized as UAC or otherwise as non-uric acid calculi (NUAC). Categorical data were compared by X2 test, continuous data by the U-Mann-Whitney test, and logistic regression test was performed for categorical data and UAC. ROC curve analysis was conducted for the HU, SDSD, and UAC, and cutoff points were set. Using data associated with UAC, a score was constructed and tested. A p<0.05 was considered statistically significant. RESULTS: A total of 92 patients were included with a median age of 55 (46–65) years and 53.3% were female. The stone composition was 67% calcium-containing, 14% uric acid, 10 % infective, 7.7% cystine, and 1% other stones. HU was significantly lower in UAC group [400 (304 – 565) vs 689 (521 – 689), p<0.001] as well as SDSD [152.2 (125.9–319.4) vs 358.1 (267.6–446.5), p<0.001]. T2D and HTN were associated with UAC (p=0.007 and p=0.041, respectively)ROC curves for UAC and mean HU showed an area under the curve (AUC) of 0.851, [Coefficient Interval (CI) 95% 0.73–0.97], p<0.001. As for SDSD, AUC was 0.808 (CI95%, 0.67–0.94). Cutoff points were selected according to the best specificity and sensitivity. Thus, a score ranging from 0-4 was created based upon variables significantly related to UAC, which were HTN, T2D, mean HU <400, and SDSD <350. Score of 0, 1, 2, 3, and 4, resulted in UAC proportion of 0%, 6.7%, 25%, 66.7%, and 100%. The AUC for the score was 0.86 (CI 95% 0.77–0.96) p<0.001. Patients with a score of 3-4 had 71.4% of UAC (p<0.001). CONCLUSIONS: This preoperative score is useful in detecting patients who might have UAC and a better selection for an alkalinizing therapy can be performed. When facing a patient with a suspected UAC, the Score can be easily applied with simple data from CT scans and clinical records. A score of 3-4 is a powerful predictor of UAC and adds to clinical decision-making for alkalizing therapy, as other items for this purpose are lacking. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e954-e955 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mario Basulto-Martínez More articles by this author Silvia Proietti More articles by this author Maria Pia Pavia More articles by this author Luis Rico More articles by this author Yuyi Yeow More articles by this author Juan Pablo Flores-Tapia More articles by this author Antonio Esqueda-Mendoza More articles by this author Franco Gaboardi More articles by this author Guido Giusti More articles by this author Expand All Advertisement Loading ...

Abstract 47 - Changing stone analysis in high risk urinary stone patients. Facts and prospects

Abstract 47 - Changing stone analysis in high risk urinary stone patients. Facts and prospects

An empirical study on hospital-based prevention of recurrent urinary stone disease in Germany

PurposeUrinary stone disease is a common disease with a prevalence of 4.7% in Germany. The incidence increased over the last decades, and recurrence rates are up to 50% in the first 5 years after diagnosis. Adequate preventive measures can avoid up to 46% of stone recurrences. These numbers outline the importance of prevention. Especially among high-risk stone formers, specific diagnostics and measures are required. Published data indicate the divergence between the importance of prevention and its implementation in everyday clinical practice. This is the first survey among German urological departments highlighting medical care concerning the prevention of recurrent urinary stone disease, identifying challenges and providing recommendations for improvements.MethodsTwo hundred and seventy urological hospital departments in Germany were anonymously surveyed about measurements to prevent recurrent stone disease. The questionnaire comprised 23 items dealing with diagnostics, counselling, knowledge among doctors concerning preventive measures and difficulties in preventing recurrent urinary stone disease.ResultsSixty-three urological departments (23.8%) answered the survey. The majority perform stone analysis at first and repeat events. Most patients with urinary stone disease receive general advice on preventive measures during their hospitalization. General recommendations focus on fluid intake and lifestyle changes. However, specific diets are infrequently recommended by inpatient urologists. Diagnostics to identify high-risk stone formers are mostly insufficient, and guideline-compliant urine tests are uncommon.ConclusionThe quality of secondary prevention needs to improve considerably. The focus should be put on identifying high-risk stone formers and offering those patients specific counselling. Furthermore, general advice on dietary recommendations should be extended.

Authentication and Chemometric Discrimination of Six Greek PDO Table Olive Varieties through Morphological Characteristics of Their Stones.

Table olives, the number one consumed fermented food in Europe, are widely consumed as they contain many valuable ingredients for health. It is also a food which may be the subject of adulteration, as many different olive varieties with different geographical origin, exist all over the word. In the present study, the image analysis of stones of six main Greek protected designation of origin (PDO) table olive varieties was performed for the control of their authentication and discrimination, with cv. Prasines Chalkidikis, cv. Kalamata Olive, cv. Konservolia Stylidas, cv. Konservolia Amfissis, cv. Throuba Thassos and cv. Throuba Chios being the studied olive varieties. Orthogonal partial least square discriminant analysis (OPLS-DA) was used for discrimination and classification of the six Greek table olive varieties. With a 98.33% of varietal discrimination, the OPLS-DA model proved to be an efficient tool to authentify table olive varieties from their morphological characteristics.

Chemical composition analysis of 649 urinary stones

Chemical composition analysis of urinary stones is a fundamental part of the metabolic workup of urolithiasis. To report the chemical composition of urinary stones using infrared spectroscopy. The chemical composition of rinary stones recovered from 649 patients aged 1 to 97 years (68% males), were analyzed using a Perkin Elmer FTIR Spectrometer, Spectrum Two. Calcium oxalate monohydrate was the most common composition found in 45% of cases, followed by mixed composition, which included three ammonium phosphate stones in 29% of cases. Pure uric acid composition was found in 16% of stones. Three cystine stones were detected. These findings do not differ from those found in developed countries.

Characterization of Mixed Urinary Stone Compositions with Dual-Source Dual-Energy Computed Tomography in Vivo Compared to Infrared Spectroscopy

Background: Most previous studies have demonstrated the possibility of using dual-source dual-energy computed tomography (DSDECT) to distinguish pure stones with high accuracy. While stones are usually composed of a mixture of substances, very few studies have focused on these stone compositions. Objectives: To retrospectively evaluate the diagnostic accuracy of DSDECT in predicting the composition of mixed urinary calculi in vivo compared to the postoperative infrared spectroscopy (IRS) for stone analysis. Patients and Methods: We retrospectively included 111 patients with 117 mixed urinary stones, detected by IRS, who underwent DSDECT between June 2018 and March 2020. Patients diagnosed with urolithiasis were examined by DSDECT preoperatively. The final stone composition was detected by IRS in vitro postoperatively. Also, the stone composition predicted by DSDECT was compared to the IRS results, known as the reference standard. Results: According to the results of IRS, 117 mixed urinary calculi, composed of a main constituent and minor admixtures, were divided into four groups: calcium oxalate (CaOx)-hydroxyapatite (HA) (n = 70); HA-CaOx (n = 36); uric acid (UA)-CaOx (n = 8); and cystine (CYS)-HA (n = 3). The accuracy of DSDECT in predicting different components of mixed urinary stones was 68.4%, 64.1%, 97.4%, and 97.5% for the CaOx-HA, HA-CaOx, UA-CaOx, and CYS-HA stones, respectively. The imaging characteristics of different mixed urinary stones, as shown by DSDECT, revealed that the CaOx-HA ratio value was lower than that of HA-CaOx (1.59 ± 0.11 vs. 1.66 ± 0.22; P &lt; 0.05). Meanwhile, the computed tomography (CT) values of CaOx-HA under 150 kV were higher than those of HA-CaOx (915.41 ± 226.84 vs .799.56 ± 252.01; P &lt; 0.05). Conclusion: Although DSDECT has a relatively low accuracy for predicting the components of CaOx-HA and HA-CaOx in vivo, its combination with the measured ratio and CT values may help differentiate these stones.

Study on Uroliths Composition in Tertiary Care Hospital of Pakistan

Background: Identification of risk factors for urolith stones formed in the urinary tract could help in preventing the recurrence. Urolith stones analysis utilized modern technology which is unfortunately not done in Pakistan on a routine basis. Development of renal failure may occur due to complications and urinary tract affected by uroliths. Objective: The current study aims to determine the composition of urolith stones seen in patients admitted in single Centre in Pakistan. Materials and Methods: This cross-sectional study was carried out on urolithstones composition surgically removed through minimum access procedure at Urology department of Ayub Teaching Hospital, Abbottabad for period of six months from October 2020 to March 2021. Urinary stones composition was measured through qualitative tests such as infrared and crystallography spectroscopy. Statistical analysis was performed in SPSS version 20. Results: A total of 82 patients with mean age ± SD 45.3±11.7 years having urinary stones were investigated in this cross-sectional study. Male to female ratio was 1.9:1. Male patients (54) (65.85%) were dominant over females (28) (34.15%) in term of stones removal. A high occurrence for urinary stones was bladder or upper urinary tract (81.6%) irrespective of their gender. Calcium containing stones were predominant in ureter, urethra and renal followed by struvite stones (56.8%). Two-third stones in struvite stones were in lower tract while uric acid, calcium phosphates and calcium oxalate were found in upper tract. Calcium oxalate account for 92.60% with mixed composition stones. Conclusion: Our study concluded that the majority of uroliths constitute calcium oxalate or phosphates and struvite stones in our setting. Uroliths formation is caused by urinary tract infection as indicated in our study. Calcium oxalate was the most common among these stones. Struvite stones were the least common one. The prevalence of stones was dominant in male patients compared to female patients. The anatomical location for calcium oxalate and struvite stones was lower tract and bladder respectively. Keywords: Uroliths, Composition, Calcium oxalate, Struvite stone

Morpho-constitutional analysis of urinary stones from patients with urolithiasis in the Democratic Republic of Congo

BackgroundUrolithiasis is increasingly diagnosed worldwide. Stone analysis is an important part in the assessment of patients with urolithiasis. However, in sub-Saharan Africa, data on the composition of urinary stones are limited. This study aimed to describe the composition and sites of urinary stones and to investigate relationship between socio-demographic characteristics, clinical profile of patients, and the composition of urinary stones.MethodsA retrospective analysis of 132 patients with urolithiasis who visited one of the seven hospitals in the Democratic Republic of Congo during eight years of study period (January 2010 to January 2018) was conducted. Stones were analyzed by infrared spectrophotometry.ResultsMost of stones analyzed (n = 82, 62.1%) originated from the upper urinary tract with a difference across gender (58.5% males vs. 41.5% females, p = 0.001). Only three stones (two from whewellite and one from anhydrous uric acid) were considered pure (2.3%), excluding the protein frame (less than 5%). Whewellite, proteins, and carbapatite were identified in 97.7%, 96.2%, and 80.3% of the stones analyzed, respectively; and in 91.7%, 89.4%, and 67.7% of the nuclei of the stones analyzed, respectively. Taking into account the proportion of each constituent in the stones analyzed, whewellite (68.9%), anhydrous uric acid (10.6%), and carbapatite (8.3%) were the main constituents in respectively 68, 9%, 10.6%, and 8.3% of the stones analyzed.ConclusionWhewellite, anhydrous uric acid, and carbapatite represented the most frequent main components of stones identified, suggesting that dietary hyperoxaluria could be an important factor in lithogenesis in the Democratic Republic of Congo.

Composition of Uroliths seen in patients in Abuja, Nigeria: a single centre retrospective analysis of 155 stones

BackgroundUroliths are stones formed in the urinary tract. Analysis of stones helps to identify risk factors for their development and prevention of recurrence. Standard stone analysis using modern technology is not routinely done in Nigeria. This study sought to determine the chemical composition of urinary stones seen in Abuja, Nigeria.MethodsThis was a retrospective study on composition of uroliths. Urinary stones surgically removed from 155 patients through minimal access surgical procedures between January 2015 and August 2019 were analysed. Optical crystallography and infrared spectroscopy were used to determine the chemical composition of the urinary stones.ResultsA total of 155 urinary stones were assembled from the patients. More stones were removed from male patients and the male to female ratio was 1.9:1. Stones were rare in the extremes of age. The predominant location (89.7%) of stones was in the upper urinary tract. All stones were of mixed composition with calcium oxalate accounting for 93.55%. Calcium oxalate, calcium phosphate and uric acid stones were more common in the upper tract, while 2 of the 3 struvite stones were found in the lower tract.ConclusionStones found in this study were of mixed composition with the most common constituent being Calcium oxalate and the least common, struvite.

Obesity rates in renal stone formers from various countries

Objective: To collect evidence on the rate of obesity in renal stone formers (RSFs) living in different climatic areas and consuming different diets. Materials and methods: Data of adult renal stone formers were retrospectively collected by members of U-merge from 13 participant centers in Argentina, Brazil, Bulgaria (2), China, India, Iraq (2), Italy (2), Nigeria, Pakistan and Poland. The following data were collected: age, gender, weight, height, stone analysis and procedure of stone removal. Results: In total, 1689 renal stone formers (1032 males, 657 females) from 10 countries were considered. Average age was 48 (±14) years, male to female ratio was 1.57 (M/F 1032/657), the average body mass index (BMI) was 26.5 (±4.8) kg/m2. The obesity rates of RSFs in different countries were significantly different from each other. The highest rates were observed in Pakistan (50%), Iraq (32%), and Brazil (32%), while the lowest rates were observed in China (2%), Nigeria (3%) and Italy (10%). Intermediate rates were observed in Argentina (17%), Bulgaria (17%), India (15%) and Poland (22%). The age-adjusted obesity rate of RSFs was higher than the age-adjusted obesity rate in the general population in Brazil, India, and Pakistan, whereas it was lower in Argentina, Bulgaria, China, Italy, and Nigeria, and similar in Iraq and Poland. Conclusions: The age-adjusted obesity rate of RSFs was not higher than the age-adjusted obesity rate of the general population in most countries. The relationship between obesity and the risk of kidney stone formation should be reconsidered by further studies carried out in different populations.

Endoscopic Papillary Abnormalities and Stone Recognition (EPSR) during Flexible Ureteroscopy: A Comprehensive Review.

Introduction: The increasing efficiency of the different lasers and the improved performance of endoscopic devices have led to smaller stone fragments that impact the accuracy of microscopic evaluation (morphological and infrared). Before the stone destruction, the urologist has the opportunity to analyze the stone and the papillary abnormalities endoscopically (endoscopic papillary recognition (EPR) and endoscopic stone recognition (ESR)). Our objective was to evaluate the value for those endoscopic descriptions. Methods: The MEDLINE and EMBASE databases were searched in February 2021 for studies on endoscopic papillary recognition and endoscopic stone recognition. Results: If the ESR provided information concerning the main crystallization process, EPR provided information concerning the origin of the lithogenesis and its severity. Despite many actual limitations, those complementary descriptions could support the preventive care of the stone formers in improving the diagnosis of the lithogenesis mechanism and in identifying high-risk stone formers. Conclusion: Until the development of an Artificial Intelligence recognition, the endourologist has to learn EPSR to minimize the distortion effect of the new lasers on the stone analysis and to improve care efficiency of the stone formers patients.

Outcomes and rates of dissolution therapy for uric acid stones.

To describe the outcomes and quantify the rate of uric acid stone medical dissolution therapy using automated, software-generated stone volume measurements. A sample of patients treated with oral dissolution therapy was reviewed from a single institution between 2008 and 2019. Baseline patient demographics, metabolic urine testing and stone characteristics were collected. Computed tomography (CT) scan images were evaluated using the quantitative Stone Analysis Software (qSAS) to obtain total stone volume (TSV), maximum diameter (MD) and stone number. Rate of dissolution usingtotal stone volume was calculated over the treatment period. Twenty-seven patients were started on oral dissolution therapy, corrected for renal function. After mean duration of 180days (range 41-531), 16 patients failed treatment resulting in surgical therapy. Twenty stones in 11 patients showed complete or partial dissolution. Compared to those who failed treatment, patients with complete orpartial dissolutionhad lower 24h urinary uric acid and higher treatment urine pH. Thirteen (65%) stones showedcomplete dissolution after a mean 167.6days. Rate of change for responders was 4.73 mm3 or 0.6% of total stone volume per day. Time to dissolution of one half of stone volume based on total stone volume was 86days (12.30weeks). Software-calculated total stone volume may be an effective method of measuring uric acid stone response to oral alkalization therapy. Stone volume decreased by 50% after 12.3weeks of treatment and could be an important benchmark fororal dissolution therapyoral dissolution therapy. Further studies with a larger sample and validation of the software are needed to confirm if this can be used to guide surveillance schedules for dissolution therapy.

LITHOSCREEN: a comprehensive screening program and database for the assessment and treatment management of patients with kidney stones.

The aim of the LITHOSCREEN project was to construct a comprehensive screening program and database for recording and assessing the various risk factors for stone-formation in patients with urolithiasis. It is intended for use in Stone Clinics and is now being made available free of charge to researchers in the field who wish to maintain a comprehensive record of their patients' medical histories, demographic backgrounds, lifestyle activities, metabolic abnormalities, biochemical risk of forming stones of various types, diet histories, stone analysis and long-term treatment records. From the recorded data for each patient, the program automatically calculates numerous functions important in the understanding of the clinical and chemical risk factors for stone-formation, including the renal handling of the ions involved, various metabolic functions, the biochemical risk of forming kidney stones (PSF), the Tiselius Indices of the supersaturation of urine with respect to calcium oxalate and calcium phosphate, the projected effects of changing the composition of each patient's urinary composition on the risk of stone recurrence, and a program for analysing the diet of patients. It automatically produces one-page Summaries of each patient's biochemical and dietary records with abnormal values highlighted according to a "traffic-light" colour-coding system and generates charts designed to improve patient compliance with treatment in the form of colour-coded "Target Diagrams" showing (a) the patient's 24-h urine composition, (b) the patient's biochemical risk of forming stones of different types and (c) the composition of the patient's diet. The Summary pages and "Target Diagrams" are suitable for inclusion in the patient's Case Notes. LITHOSCREEN also produces charts projecting the effect of changing the composition of urine on the patient's biochemical risk of forming further stones. These graphs provide clues as to which urinary risk factors to target to reduce the patient's risk of stone recurrence.

Patients with encrusted ureteral stents can be treated by a single session combined endourological approach.

ABSTRACTPurpose:To describe our experience in the management of retained encrusted ureteral stents using a single session combined endourological approach.Materials and Methods:Patients with retained encrusted ureteral stents who had been submitted to a single session combined endourological approach from June 2010 to June 2018 were prospectively evaluated. Patients were divided according to the Forgotten-Encrusted-Calcified (FECal) classification. The stone burden, surgical intervention, number of interventions until stone free status, operation time, hospital stay, complications, stone analysis, and stone-free rate were compared between groups. ANOVA was used to compare numerical variables, and the Mann-Whitney or Chi-square test to compare categorical variables between groups.Results:We evaluated 50 patients with a mean follow-up of 2.9±1.4 years (mean±SD). The groups were comparable in terms of age, sex, laterality, BMI, comorbidities, ASA, reason for stent passage, and indwelling time. The stone burden was higher for grades IV and V (p=0.027). Percutaneous nephrolithotomy was the most common procedure (p=0.004) for grades IV and V. The number of procedures until the patients were stone-free was 1.92±1.40, and the hospital stay (4.2±2.5 days), complications (22%), and stone analysis (66% calcium oxalate) were similar between groups. The stone-free rate was lower in grades III to V (60%, 54.5%, and 50%).Conclusions:The endoscopic combined approach in the supine position is a safe and feasible technique that allows removal of retained and encrusted stents in a single procedure. The FECal classification seems to be useful for surgical planning.

P0253 - Predicting stone composition by dual energy computed tomography before extra corporeal shock wave lithotripsy and comparing it with stone analysis

P0253 - Predicting stone composition by dual energy computed tomography before extra corporeal shock wave lithotripsy and comparing it with stone analysis

And which stone type are you?

And which stone type are you? Abstract. Knowledge about the stone type is essential for therapy, prophylaxis and prognosis of kidney stone disease. Stone types can completely change in the course of a stone disease and therefore every kidney stone should be analyzed. This narrative review deals with some aspects of methods for analysis and types of kidney stones, with frequencies of different stone types as well as with general and specific mechanisms of kidney stone formation and seeks to stimulate a more in-depth study of this topic.

MO118ROLE OF DUAL ENERGY COMPUTED TOMOGRAPHY IN PREDICTING THE CHEMICAL COMPOSITION OF STONES

Abstract Background and Aims Dual-energy CT (DECT) has shown excellent outcomes in differentiating the chemical composition of the urinary stones with a great accuracy. A reliable determination of the chemical type of the stone help the clinician to better satisfy treatment options for the patient- medical versus surgery We used the DECT in our study to assess the accuracy of non-invasive differentiation of renal stones using the 3rd generation dual-source computed tomography (CT) scanner in determining the chemical composition of renal stones and to determine appropriate management based on DECT determined chemical composition of stones. Method This prospective study was conducted in the Department of surgery and radiodiagnosis and Imaging, Era Medical College and RML institute of Medical Sciences , Lucknow over the study period, i.e., November 2016 to May 2018 . The patients were those referred for non-contrast/contrast CT for the diagnosis/evaluation of urolithiasis from the department of Surgery admitted for PCNL/ESWL/therapeutic ureterorenoscopy. DECT ratios of the various stones were noted and compared with the post extraction analysis of stones for composition. A total of 100 patients were included in the study, and their DECT results were compared with the post-extraction analysis (by infrared spectroscopy as the standard comparative method). Results Mean age of patients was 41.15+/- 10.08 years with 64% being males. DECT was highly sensitive and specific in the diagnosis of various types of calculi based on their dual-energy ratio. It was found to be 100% sensitivity and 97.2% specificity for differentiating UA stones with level of agreement between chemical and DECT was almost perfect (k= .951) .However for hydroxyapatite stones was substantial (k=.889). Most of the stones belonged to non-UA category (72%), and only 28% were UA calculi. The sensitivity and specificity in differentiating a calcium oxalate from non-calcium oxalate calculus was 94.1% and 95.5%, respectively. Conclusion DECT highly sensitive and effective in characterizing chemical composition of the urinary stones and can help in determining the management plan and reduce the unnecessary burden of surgical interventions.

Does potassium citrate administration change the type and composition of encrusted material on Double-J stent compared to primary stone?

PurposeTo evaluate the effect of potassium citrate administration on the composition of encrusted material on the ureteral stent after Double-J insertion.MethodsWe designed a randomized clinical trial for our study; 65 patients that underwent transurethral lithotripsy and Double-J stent insertion were included in the study after informed consent and divided into two groups. In the first group (33 patients) potassium citrate was prescribed after surgery till stent removal and the second group (32 patients) followed without prescribing this medication. After stent removal, encrusted materials on removed stents were analyzed then the type and composition of encrusted material compared with the primary stone that was removed.ResultsOur results revealed that the type and composition of primary stone and encrusted stone were similar in patients that do not receive potassium citrate (p-value of 0.073, 0.251 and 0.944 for calcium oxalate, uric acid, and calcium phosphate respectively). In patients that taking potassium citrate rate of calcium oxalate (p-value < 0.001) and uric acid (p-value < 0.001) material on encrusted stent significantly decreased compared with the non-intervention group.ConclusionResults of this study revealed that taking of potassium citrate after ureteral stent insertion significantly decreases the formation of calcium oxalate and uric acid encrusted material on Double-J stent so it could be recommended for prevention of stent encrustation in patients that primary stone analysis are calcium oxalate and uric acid stone.

EDXRF, FTIR, and XRD characterization of low calcium oxalate urinary stones collected from arid area

Low calcium oxalate urinary stones from the kidney, bladder, and ureter have been collected from the arid area (Taif, Saudi Arabia). After careful washing and drying of the collected stones, the samples were converted into a contamination‐free homogenous fine powder with a particles' size smaller than 50 μm. The processed urinary stone powders were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR), laboratory setup and synchrotron radiation X‐ray diffraction (XRD), and energy‐dispersive X‐ray fluorescence (EDXRF). The activated function groups, quantitative phase analysis, and the semi‐quantitative elemental analysis of the present urinary stones were identified. Seventeen elements were measured in most of the urinary stone samples. The significant elements are Ca, P, S, Cl, Zn, K, Fe, and Cu, whereas other elements were found alternatively in a few number of urinary stone samples. It was recognized that Ca exists with low concentration, which indicates the presence of different calcium phases even with low percentages. In 33% of the urinary stones, the phosphorus (P) was not measured, but there were high concentrations of sulfur (S) and low concentrations of Ca up to 2.15 ± 0.05%. The ATR‐FTIR results indicate that the most compounds of the present urinary stones were urea and cystine combined with low ratios of calcium oxalate and calcium phosphate compounds. The quantitative phase analysis of the XRD of selected samples proves the presence of the cystine, urea, and calcium oxalate phases with different weight percent.