Stone Characteristics Research Articles

A new hybrid MCDM method for optimizing natural stone se-lection for building envelopes

Most kinds of natural stones are perfect coating materials. Through utilizing stones with less thermal conductivity coefficients, isolation of constructions improves with energy effective resolution. Modern building technologies prefer either decreasing stone to the weakest plausible extents or utilizing natural stones because natural stones have lower thermal conductivity with lighter weights. For this reason, first, the thermal and physical characteristics of natural stones used as coating material on the exterior walls of the buildings were investigated in this study. Then, in the light of these characteristics, natural stones with the best performance in terms of energy efficiency were determined using multi-criteria decision-making methods including FFSWARA and COBRA. The findings show that compressive strength is the most significant criteria and Isparta andesite stone is the most superior natural stone in terms of performance. This study contributes to the literature in three ways. First, the COBRA method used in this study has recently been introduced to the literature. Therefore, it has not been covered much in the literature. Second, this method has not been used in the selection of natural stone selection in the literature to our best knowledge. Third, this method has not been used together with the FFSWARA method before.

Increasing the Biostability of Concrete by the Introduction Of Additives

To increase the resistance to fungal corrosion and improve the performance of concrete cement stone, it is proposed to introduce calcium stearate and active metal nitrates in an amount of 0.5% by weight of cement into the cement mixture at the manufacturing stage. To determine the degree of corrosion damage of cement stone by fungal microorganisms Aspergillus niger, porosity, density, water absorption and strength were determined. It has been found that the introduction of a hydrophobic additive of calcium stearate into the cement mixture during the manufacture of concrete reduces water absorption, reduces porosity and increases strength. Additives of nitrates of active metals do not affect the characteristics of the cement stone of concrete. As a result of 6 months of fungal corrosion, the water absorption, porosity and density of cement stone containing calcium stearate did not change, and the strength decreased by 4%. Metal nitrates do not prevent damage to the cement stone by microorganisms, but slow down the flow of aggressive substances to the surface of the reinforcement in concrete. The combined introduction of calcium stearate and nitrates into the cement mixture will improve the characteristics of concrete, increase its corrosion resistance and ensure the safety of reinforcement in concrete.

ОГЛЯД ПЕРСПЕКТИВ ЗАСТОСУВАННЯ СМУГ ВИГОТОВЛЕНИХ ЗА ТЕХНОЛОГІЄЮ FIBERGLASS ДЛЯ АРМУВАННЯ АРХІТЕКРУРНО-ДЕКОРАТИВНИХ ВИРОБІВ З ПРИРОДНОГО КАМЕНЮ

Purpose. The purpose of this study is to assess the feasibility of using fiberglass strips manufactured with technology for reinforcing architectural decorative products made of natural stone by comparing their strength properties and behavior under bending strength. Methodology. The preparation of samples for strength testing has been carried out, and recommendations regarding the process have been described. Recommendations have been provided regarding the preparation, configuration, and implementation of the main tools and materials involved in the course of the research. Components of the experiment aimed at determining the strength characteristics of the samples have been developed and described. In accordance with the set tasks and the array of data obtained empirically, numerical values of the strength characteristics of natural stone products under external loads have been calculated. The calculations are performed in accordance with the general principles of theoretical and applied mechanics. Results. The influence of reinforcement on the strength of stone has been studied, expanding existing theoretical knowledge about the strength properties of stone and the possibilities for their improvement. New theoretical models and methods for assessing the strength characteristics of stone, taking into account the influence of reinforcing elements, have been developed, contributing to a deeper understanding of the processes occurring in the structure of stone during reinforcement. Scientific novelty. The existing methods of reinforcing natural stone products have been systematized and reviewed, and the ways to optimize them using modern composite material manufactured with fiberglass technology have been suggested. The feasibility of applying internal reinforcement technology to enhance the strength properties of natural stone products has been substantiated. For the first time, the methodology and effectiveness of applying internal reinforcement manufactured with fiberglass technology to improve the strength properties of products from the Pokostiv deposit granodiorite have been analyzed. Practical significance. The practical importance of the obtained results lies in the opportunity to transform theoretical knowledge into practical recommendations for improving the technology of manufacturing products from natural stone to enhance their reliability in operation and simplify the manufacturing process.

The Impact of Ureteral Wall Thickness on Spontaneous Passage and Development of Long-term Ureteral Stricture in Patients with Ureteral Stone

To evaluate the association of ureteral wall thickness (UWT) with spontaneous passage (SP) of ureteral stones and formation of ureteral stricture (US) in patients who underwent ureterorenoscopy for ureteral stones. Cohort study. Department of Urology, University of Health Sciences, Bursa Yuksek Ihtisas Training and Research Hospital, Turkey, between January 2019 and June 2021. One hundred and sixty-nine patients with ureteral stones were restrospetively reviewed for maximum stone diameter, stone density, degree of hydronephrosis, parenchymal thickness, and UWT measurement from CT images. The patients were divided into two groups; patients who had (group 1) and had not (group 2) undergone SP of ureteral stones. These two groups were compared for stone characteristics and UWT. Ureterorenoscopy was performed on 52 patients who did not experience SP. Data related to the passage of guide wire and radio-opaque material, drainage method, ureteral wall injury and patients who developed US were recorded. Ureterorenoscopy group were divided into two groups of patients who did and did not develop stricture. These two groups were compared for stone characteristics and perioperative findings. Of the 169 patients, 106 (62,7%) patients spontaneously passed stones. Ureterorenoscopy was performed on 52 patients. US developed in 9 (17%) patients. Maximum stone diameter, density, and antero-posterior (AP) diameter of the renal pelvis and UWT were statistically different between both groups. The degree of hydronephrosis, ureteral wall injury, density, AP diameter of the stones, parenchyma thickness, length of hospital stay, and UWT were found to be significantly increased in the stricture group. UWT is a simple measurement that can be used to predict SP of ureteral stones. It can also predict the development of US after ureterorenoscopy in long-term. Ureteral calculi, Ureterorenoscopy, Ureteral wall thickness, Ureteral stricture.

Kidney Stone Feature Extraction from the Selected Kidney Region Using Rapid Haralick Polygonal and Surface Algorithm

Kidney Stone Feature Extraction from the Selected Kidney Region Using Rapid Haralick Polygonal and Surface Algorithm

Extracorporeal Shock Wave Lithotripsy (ESWL): An Evaluation of Success in Low, Medium and High Stone Density

Objective: To find the frequency of patients of renal calculi with different stone densities and to evaluate the success rate of ESWL treatment in selected groups of patients i.e. low, medium and high stone density. Methodology: In this descriptive case series, at Department of Urology, Services Hospital, Lahore was conducted and enrolled a 100 cases with single, radiopaque renal stone of 1-2 cm (10 to 20 mm), between 15-80 years of either gender whereas those with calculus in nonfunctioning kidney (GFR less than 15 ml/min), calculus in Pyonephrotic kidney, presence of JJ stent and having previous surgery for stone on same side or radiolucent stones were excluded from this study. All sessions of ESWL were performed following departmental protocol. 3 weeks after the ESWL session, the outcome was evaluated by plain X-ray KUB and USG KUB. In this analysis, ESWL success was defined as either total stone clearance or the presence of clinically insignificant residual fragments (CIRFs) (4 mm, peripheral, not producing renal colic, with no infection or extensive hematuria). Results: Stone density was in the range of 335-1900 HU with a mean density of 851.1 (±418) HU. Patients with medium density group (500-1000HU) were significantly greater than other two groups. MDG had frequency of 51% followed by LDG (25%) and HDG (24%). Overall, ESWL success rate was 82% in all the 100 patients of renal calculi. Success rate was greatest in LDG i.e. 100%. MDG had a success rate of 90% and only 45.8% of the patients in HDG had succees after ESWL treatment. Success rate decreased as the stone density increased. Conclusion: the stone density has a significant impact on success of ESWL. NCCT stone characteristics like mean density in HU and demographic characteristics are potential predictors for evaluation of success of ESWL. Keywords: Kidney stones, ESWL, Stone density

Дизайн состава штукатурного раствора для реставрации каменных и кирпичных памятников архитектуры

Purpose: To investigate the possibility of using artificial pozzolana to create modified gypsum lime mortar, recommended for architecture monument restoration. Methods: At the research pursued, there were used Russia State Standard GOST 125-79 "Plaster Binders. Technical specifications", GOST 23789-79 "Plaster Binders. Test Methods", GOST 10180-90 "Concretes. Methods for Determining Strength by Control Samples", GOST 24544-81 "Concretes. Methods for Determining Shrinkage and Creep Deformations", GOST 8735-14 "Sand for Construction Works. Test Method" and GOST 8736-14 "Sand for Construction Works. Technical Conditions". It has been established experimentally that to create reliable matrix, compatible with traditional materials of historical masonry, the use of restoration composition, including metakaolin and dolomite flour, is effective. Results: The process of restoration material design to replace damaged plaster of walls and ceilings is presented, strength characteristics of stones of various compositions on the basis of air binders are discussed, conclusion is made on the necessity to develop restoration material two types: for to put on lime plaster family and for - gypsum-lime plaster family. Practical significance: The results obtained can be used at partial or complete replacement of plaster that would allow to preserve building architectural appearance.

Stone tools of the Neolithic settlement of Mergen 8

In this paper, stone tools of the Neolithic settlement of Mergen 8, located in the forest-steppe zone of Wes-tern Siberia in the Lower Ishim river basin, are analyzed. The mixed cultural layer of the settlement contained materials from two periods of its inhabitation, associated with the Boborykino Culture of the early Neolithic period and with the pottery ornamented with comb stamp of the late Neolithic period. The identification of the two chrono-logically different types of pottery raised the question of possibility of separating the stone implements. The aim of this work is to attempt differentiation from the mixed cultural layer of the groups of stone tools associated with a certain cultural and chronological section of the settlement. The peculiarity of the cultural layer of the Mergen 8 settle-ment was the presence of the dwelling 1 and some pits unimpaired by the upper horizons. In the methodological aspect of this work, stratigraphic and planigraphic analyzes with the aid of the feedstock characteristics of stone formed the basis, on which a relatively clean complex of quartz sandstone and flint was isolated, associated with the filling of the dwelling 1, in which pottery of the Boborykino Culture was found. The differentiation of the stone tools from the mixed layer was based upon the raw material that was found in the bottom part of the dwelling’s ditch, undisturbed by other layers. The complex of the stone tools made of jasper quartzite and schist, established during the field fixation, is associated with the comb-type pottery. Thus, in the course of our study, out of 417 finds of the stone tools 276 (66 % of the entire complex) were assigned to the Boborykino complex, 50 (12 %) to the comb complex, and 91 finds (22 %) were not possible to attribute to any type of pottery. Bearing in mind that separation by feedstock has a cer-tain degree of conventionality, it should be noted that the stone taken from the undisturbed near-bottom part of the Boborykino dwelling 1 reflects the most plausible nature of the stone industry of this period of inhabitation. In addi-tion, in our opinion, attempts to link stone implements and their features with a certain type of pottery facilitate the formation of a clear concept of the development of the stone industry in the region in the Neolithic.

The association between ureteral wall thickness and need for additional procedures after primary ureteroscopy in patients with ureteral stones above the iliac crest.

To examine the parameters affecting the need for additional procedures in the primary ureteroscopy treatment in patients with ureteral stones above the iliac crest level. Seventy-one patients were included in the study who were ≥ 18 years old and had undergone ureteroscopy (URS) for ureteral stones above the iliac crest level between 2018-2020 and had a non-contrast-enhanced abdominal computed tomography before the procedures were included in the study. Patients and stone characteristics were prospectively collected. The results were evaluated six weeks after URS. The absence of any residual fragment was thought to indicate stone-free status. The patients with failure were referred for the additional procedures. The median patient age was 51 years [interquartile range (IQR): 18-66]. The median transverse stone diameter was 9.5 mm (IQR: 7.1-11.4), and the median ureteral wall thickness (UWT) was 5.8 mm (IQR: 4.3-6.5). In the univariate analysis, UWT (p < 0.001), presence of multiple stones (p = 0.008), and stone length (p = 0.022) affected stone-free status. The multivariate analysis revealed UWT as the only independent factor affecting the need for additional procedures after URS (p = 0.028). In the receiver operating characteristic curve analysis, the best threshold value for UWT according to the outcomes was identified as 5.8 mm. Ureteral wall thickness was the only independent parameter determining the need for additional procedures and affecting the treatment outcomes after the URS procedure.

The characterization of in vivo urinary phospate stones by spectral CT.

To analyze characteristics of urinary phospate stones using spectral CT (rapid kV switching dual-energy CT) in vivo. This study included 55 single-composition and 36 mixed-composition infection stones, which were derived from 38 patients (15 males and 23 females), with median age of 49years old (range 10-71). The effective nuclear number (Zeff) peak, its high and low points, average Zeff value, water- and iodine-based values, and average CT values were detected. Post-surgical infrared spectroscopy results were compared with CT findings. In single-composition stones, 21 were of carbapatite, 20 of struvite, and 14 of brushite. These stones differed significantly in Zeff peak, its low and high points, average Zeff value, and iodine-based value. Three compositions had similar water-based and average CT values. The 36 mixed-composition stones all had two Zeff peaks, which included 23 of carbapatite, 25 of struvite, and 24 of brushite. When 95% confidence intervals of Zeff peaks in single-composition stones were as standard, this standard overlapped 82.6% of carbapatite, 88.0% of struvite, and 87.5% of brushite in mixed-composition stones. But many low and high points in three mixed-composition groups were outside the 95% confidence interval (overlap < 70%). The significance differences were not observed in water/iodine-based, average Zeff and average CT values. Zeff peaks in vivo spectral CT revealed some characteristics of various phospate stones.

A retrospective cohort study on the use of machine learning to predict stone-free status following percutaneous nephrolithotomy: An experience from Saudi Arabia.

Machine learning techniques have been used extensively in the field of clinical medicine, especially when used for the construction of prediction models. The aim of the study was to use machine learning to predict the stone-free status after percutaneous nephrolithotomy (PCNL). This is a retrospective cohort study of 137 patients. Data from adult patients who underwent PCNL at our institute were used for the purpose of this study. Three supervised machine learning algorithms were employed: Logistic Regression, XGBoost Regressor, and Random Forests. A set of variables comprising independent attributes including age, gender, body mass index (BMI), chronic kidney disease (CKD), hypertension (HTN), diabetes mellitus, gout, renal and stone factors (previous surgery, stone location, size, and staghorn status), and pre-operative surgical factors (infections, stent, hemoglobin, creatinine, and bacteriuria) were entered. 137 patients were identified. The majority were males (65.4%; n=89), aged 50 years and above (41.9%; n=57). The stone-free status (SFS) rate was 86% (n=118). An inverse relation was detected between SFS, and CKD and HTN. The accuracies were 71.4%, 74.5% and 75% using Logistic Regression, XGBoost, and Random Forest algorithms, respectively. Stone size, pre-operative hemoglobin, pre-operative creatinine, and stone type were the most important factors in predicting the SFS following PCNL. The Random Forest model showed the highest efficacy in predicting SFS. We developed an effective machine learning model to assist physicians and other healthcare professionals in selecting patients with renal stones who are most likely to have successful PCNL treatment based on their demographics and stone characteristics. Larger multicenter studies are needed to develop more powerful algorithms, such as deep learning and other AI subsets.

Renal stone density on native CT-scan as a predictor of treatment outcomes in shock wave lithotripsy.

Extracorporeal shock wave lithotripsy (ESWL) is considered a standard treatment for nephrolith or kidney stones measuring less than 20 mm. Anatomical, machine-related, and stone factors play pivotal roles in treatment outcomes, the latter being the leading role. This paper examined the relationship between stone density on native CT scans and ESWL treatment to remove renal stones concerning several treatments. One hundred and twenty patients (64 males and 56 females) were enrolled and completed the study from April 2019 to September 2020. Inclusion criteria were a single renal pelvis stone of 5-20 mm to be treated for the first time in adult patients with no urinary or musculoskeletal anatomical abnormalities. We assessed patients' renal function and obtained stone characteristics using a native CT scan. Patients were then scheduled for ESWL by the same machine and operator under fluoroscopy, with two-week intervals between treatment sessions when more than one treatment session was required. Before each new session, a new KUB-US was performed to reevaluate the stone. One hundred and twenty patient records were analyzed, 64 (53.3%) males and 56 (46.7%) females, with a mean age of 38.6 years and a mean stone size of 13.15 mm. Treatment with ESWL cleared stones in 76 (63.3%) patients, while 44 (36.7%) failed the treatment. The mean stone density in patients whose stones were cleared was significantly lower (661 vs. 1001) (P<0.001). Estimating renal calculus (or kidney stone) density on a native CT scan might help prognosticate ESWL treatment outcomes regarding stone clearance rates and the number of sessions required to clear a stone.

Role of Preoperative Ureteral Stent on Outcomes of Retrograde Intra-Renal Surgery (RIRS) in Children. Results From a Comparative, Large, Multicenter Series

To assess outcomes of pre-stenting versus non-pre-stenting in children undergoing retrograde intrarenal surgery (RIRS) for intrarenal stones. Children/adolescent with kidney stones undergoing RIRS in 9 centers between 2015 and 2020 were retrospectively reviewed. ureteral lithotripsy, bilateral procedures. Stone-free status was evaluated at 3-month and defined as a single residual fragment (RF) ≤2 mm/absence of multiple fragments. Patients were divided into two groups (Group 1 no-prestenting; Group 2 prestenting). Student's, Chi-square and Fisher's exact test was used to assess difference between groups. Univariable and multivariable logistic regression analysis were performed to predict RF. Statistical significance: P-value <0.05. Three hundred eighty-nine children/adolescents were included (192 patients in Group 1). Prestented patients were younger compared with non-prestented (mean age 8.30 ± 4.93 vs 10.43 ± 4.30 years, P < 0.001). There were no differences in stone characteristics (number, size, locations). Lasing and total surgical time were similar. Urinary tract infections were more prevalent in Group 2 (10.7%) compared to Group 1 (3.7%, P=0.016). Sepsis occurred in 2.1% of patients in Group 2 and no patient in Group 1 (P=0.146). 30.7% patients in Group 1 and 26.4% in Group 2 had RF (P=0.322). In univariate logistic regression analysis, stone size was associated with RF (OR 1.12 95%CI 1.06-1.18, P < 0.001), whereas Thulium fiber laser with a lower incidence (OR 0.24 95%CI 0.06-0.69, p=0.020). Multivariate logistic regression analysis showed that stone size was associated with RF (OR 1.20 95%CI 1.08-1.36, P=0.001). RIRS showed similar stone-free rate in pre and non-prestented children/adolescents, although prestented patients were younger. A higher risk of post-operative infections was reported in prestented patients.

Quantitative Analysis of Mucin Expression Using Combined Alcian Blue-Periodic Acid Schiff (AB-PAS) Stain and Combined High Iron Diamine-Alcian Blue (HID-AB) Stain and the Correlation With Histomorphological Score in Chronic Calculous Cholecystitis.

Introduction Chronic calculous cholecystitis is the most common and important contributing factor for cholecystectomy across the country, with a prevalence of 2-29%. Cholesterol supersaturated bile plays a major role in stone formation. It is very essential to identify the pathogenesis of stone formation in order to prevent its formation. This study is aimed to evaluate histomorphological features of chronic calculous cholecystitis and to quantitatively evaluate alteration in mucin expression using the combined Alcian blue-periodic acid Schiff (AB-PAS) stain and the combined high iron diamine Alcian blue (HID-AB) stain, to correlate with each other and also with biochemical features of gall stones. Methods A cross-sectional study of 64 chronic calculous cholecystitis were taken for histomorphological assessment and grading using Hematoxylin and Eosin (H&E) stainand Masson's trichrome stains.Expression of the type of mucins wasanalyzed using histochemical stains by a standardized scoring system. Results A significant positive correlation was observed between an increase in grades of inflammation and fibrosis with an increase in the quantity of sialomucin and neutral mucin in the deep layers of epithelium, and a significant negative correlation was observed between an increase in grades with a decrease in acidic mucin and sulfomucin of both superficial and deep epithelium except sulfomucin in fibrosis. No significant correlation was obtained with muscle thickness, adipose tissue deposition, and epithelial hyperplasia. A higher frequency of mixed-type stones was associated with severe inflammation. Conclusion Inflammation and fibrosis were strongly correlated with quantitative alteration and reversal of mucin composition in chronic cholecystitis; hence we conclude that these features play a significant role in the pathogenesis of stone formation. Using Combined AB(2.5pH)-PAS stain and Combined HID-AB(2.5 pH) stain to detect mucin hypersecretion and composition of altered mucin is relatively accurate and cost-effective rather than performing costly immunohistochemical (IHC) markers.

Possibilities of multislice computed tomography in assessing the structural and compositional features of calcium-containing urinary stones

The aim: to study the X-ray density index (HU) in calcium-containing urinary stones with different structural and compositional features. The structural and compositional features of 118 samples of calcium-containing urinary stones, which were obtained as a result of extracorporeal shock wave lithotripsy, percutaneous nephrolithotripsy and ureteroscopic lithotripsy in patients with kidney and ureteral stones were studied. The structural features of the stones were evaluated by conducting a crystal-optical analysis, during which the linear dimensions, shape, color and degree of transparency of crystalline elements were estimated, and the volume fractions of the amorphous and crystalline phases in the sample structure were calculated. The compositional features of kidney stones were studied on the basis of a qualitative and quantitative assessment of their mineral composition by infrared spectroscopy. X-ray density of calcium-containing kidney stones was assessed based on the data of computed tomography without contrast, which was performed in all patients in the preoperative period. Structural and compositional features of calcium-containing urinary stones are characterized by the presence in their composition of calcium oxalate compounds in the form of vewellite and weddelite, as well as calcium phosphate in the form of apatite, hydroxylapatite, fluorapatite, carbonate apatite, which, depending on the stage of crystallization, can be in amorphous, amorphous-crystalline or crystalline state. The X-ray density of this type of urinary stones, according to multislice computed tomography, corresponds to the range of 1090-1785 HU. There is a direct correlation between the level of X-ray density of the stone and the volume fraction of the crystalline phase in its structure.

Tubeless Ureterorenoscopy-Our Experience Using a 120 W Laser and Dusting Technique: Postoperative Pain, Complications, and Readmissions.

Introduction and Objective: Both double J-stent (DJS) and ureter catheter (UC) drainage represent routine practice following ureterorenoscopy. In select situations, a tubeless approach is possible and safe. In tubeless cases, we use a sheathless dusting technique with the Lumenis® MOSES Pulse™120 H Holmium: YAG laser. We evaluated these three drainage subgroups and compared postoperative pain, complications, and readmissions. Methods: A retrospective database of 269 consecutive patients who underwent primary ureterorenoscopy for the treatment of upper urinary tract stones between October 2018 and August 2019. The cohort was divided according to post-operative drainage as Tubeless, UC, and DJS. The decision on whether to perform post-operative drainage was by surgeon preference. Demographic and clinical parameters such as stone location, number, and burden, hydronephrosis grade, and postoperative complications (fever, acute renal failure, and the obstruction of the upper urinary tract by Stone Street) were assessed. Pain was assessed using a 0−10 Visual Analog Scale score (VAS) and the use of analgesics by dose/case in each group. Results: There were 70 (26%) tubeless, 136 (50%) UC, and 63 (24%) DJS cases. Patients drained with DJSs had a significantly higher stone burden, more severe obstruction, and prolonged operative time. Tubeless and UC-drained patients had the same stone characteristics with maximal diameters of 8.4 (6.1−12) mm and 8 (5.2−11.5) mm in comparison to the stented group, with 12 (8.6−16.6) mm, p < 0.01. The operation time was the longest in the stented group at 49 min (IQR 33−60) in comparison to the UC and tubeless groups at 32 min (23−45) and 28 min (20−40), respectively (p < 0.001). Auxiliary procedures were more prevalent in the stented group, but the overall stone-free rate was not significantly different, p = 0.285. Postoperative ER visits, readmissions, and complications were the highest in the UC-drained group, at 20% in the UC vs. 6% in the tubeless and 10% in the stented groups. Post-operative pain levels and analgesic use were significantly lower in the tubeless group with a significant reduction in opiate usage. Conclusions: A tubeless approach is safe in selected cases with fewer post-operative complications. While DJS should be considered in complex cases, UC may be omitted in straightforward cases since it does not appear to reduce immediate postoperative complications. Those fitted for tubeless procedures had improved postoperative outcomes, facilitating outpatient approach to upper urinary tract stone treatment and patient satisfaction.

CT-Based Predictor for the Success of 12/14-Fr Ureteral Access Sheath Placement.

Ureteral access sheaths (UAS) are widely used in retrograde intrarenal surgery (RIRS), and this study aimed to develop a model for predicting the success of UAS placement based on computed tomography. We analyzed the clinical data of 847 patients who received ureteroscopy. Data on patient and stone characteristics and several computed tomography (CT)-based measurements were collected. A nomogram predicting the success of UAS placement was developed and validated using R software. Two hundred and forty-seven patients were identified. Twenty-five patients (10.1%) failed to pass through the UAS. A model with three factors including the short diameter of ureteral calculi, the short diameter of hydronephrosis, and the diameter of the narrowest part of the renal parenchyma was to be strongly practical and had a high area under the curve on internal validation (80.3%). Using a threshold cutoff of 92%, the sensitivity and specificity for predicting UAS placement were 0.35 and 0.92, respectively. Our study provides a nomogram for predicting the success of UAS placement, and this model could help discriminate patients who are likely to suffer from failed UAS insertion; preoperative ureteral stenting is recommended according to the prediction.

The impact of Hounsfield unit-related variables on percutaneous nephrolithotomy outcomes

We aimed to identify the association between Hounsfield Unit(HU)-related variables and percutaneous nephrolithotomy (PCNL) outcomes. We enrolled patients with single renal stones (1–3 cm) who underwent single-tract PCNL between January 2014 and October 2019. Demographics and stone characteristics were retrospectively reviewed. Preoperative computerized tomography (CT) and follow-up CT within at least 3 months after PCNL were included in this analysis. Stone-free status was defined as residual stone measuring ≤ 2 mm within 3 months postoperatively. HU and cross-sectional area (CSA) were measured using the free-draw technique. We analyzed HU-related variables using logistic regression model for outcomes. Altogether, 188 out of 683 patients met the inclusion criteria. The stone-free rate (SFR) was 79.2%. There were no significant differences in age, sex, BMI, ASA class, laterality, pre-op shockwave lithotripsy, stone size, stone burden, skin-to-stone distance, and HU between the stone-free and remnant groups. CSA and HU/CSA in the stone-free and remnant groups were 94.5 ± 46.1 and 128.3 ± 98.5 (p = 0.043) and 10.1 ± 5.6 and 7.3 ± 3.4 (p = 0.001), respectively. Multivariate logistic regression analysis revealed that pelvis, ureteropelvic junction stones, and HU/CSA were independent predictors of SFR. HU did not affect PCNL outcomes. We believe that HU/CSA could be used for determining stone treatment plans and predicting outcomes.

The Laparoscopic Cholecystectomy and Common Bile Duct Exploration: A Single-Step Treatment of Pediatric Cholelithiasis and Choledocholithiasis.

Background: In recent years, complicated biliary tract diseases are increasingly diagnosed in children. Laparoscopic exploration of the common bile duct (LCBDE) followed by laparoscopic cholecystectomy has gained popularity in children. The aim of this study was to investigate the outcomes of LCBDE in children and compare them with the treatment outcomes of previously used endoscopic retrograde cholangiopancreatography (ERCP). Methods: From January 2000 to January 2022, a total of 84 children (78.5% female) underwent laparoscopic cholecystectomy with a median follow-up of 11.4 (IQR 8, 14) years. Of these, 6 children underwent laparoscopic cholecystectomy (LC) + ERCP and 14 children underwent LCBDE for choledochiothiasis. The primary end point of the study was the success of treatment in terms of the incidence of complications, recurrence rate, and rate of reoperation. Secondary endpoints were stone characteristics, presenting symptoms, duration of surgery, and length of hospital stay. Results: The majority of patients were female in both groups (83.5% vs. 85.7%), mostly overweight with a median BMI of 27.9 kg/m2 and 27.4 kg/m2, respectively. Obstructive jaundice, colicky pain, acute pancreatitis, and obstruction of the papilla were the most common symptoms in both groups. The majority of patients (68%) had one stone, whereas two or more stones were found in 32% of patients. The median diameter of the common bile duct was 9 mm in both groups. The procedure was successfully completed in all patients in the ERCP group. In the group of patients treated with LCBDE, endoscopic extraction of the stone with a Dormia basket was successfully performed in ten patients (71.4%), while in the remaining four patients (28.6%) the stones were fragmented with a laser because extraction with the Dormia basket was not possible. The median operative time was 79 min in the LCBDE group (IQR 68, 98), while it was slightly longer in the ERCP group, 85 min (IQR 74, 105) (p = 0.125). The length of hospital stay was significantly shorter in the LCBDE group (2 vs. 4 days, p = 0.011). No complications occurred in the LCBDE group, while two (40%) complications occurred in the ERCP group: pancreatitis and cholangitis (p = 0.078). During the follow-up period, no conversions, papillotomies, or recurrences were recorded in either group. Conclusions: Exploration of the common bile duct and removal of stones by LCBDE is safe and feasible in pediatric patients for the treatment of choledocholithiasis. Through this procedure, choledocholithiasis and cholelithiasis can be treated in a single procedure without papillotomy or fluoroscopy. Compared with LC + ERCP, LCBDE is associated with a shorter hospital stay. The incidence of complications was rather low but not statistically significant.

Determinants of ureteral obstruction after percutaneous nephrolithotomy

BackgroundUreteral obstruction after percutaneous nephrolithotomy (PCNL) may require prolonged drainage with a nephrostomy tube (NT) or ureteral stent, but it is not well understood how and why this occurs. The goal of this study was to identify risk factors associated with postoperative ureteral obstruction to help guide drainage tube selection.MethodsProspective data from adult patients enrolled in the Registry for Stones of the Kidney and Ureter (ReSKU) who underwent PCNL from 2016 to 2020 were used. Patients who had postoperative NTs with antegrade imaging-based flow assessment on postoperative day one (POD1) were included. Patients with transplanted kidneys or those without appropriate preoperative imaging were excluded. We assessed the association between patient demographics, stone characteristics, and intraoperative factors using POD1 antegrade flow, a proxy for ureteral patency, as the primary outcome. Stepwise selection was used to develop a multivariate logistic regression model controlling for BMI, stone location, stone burden, ipsilateral ureteroscopy (URS), access location, estimated blood loss, and operative time.ResultsWe analyzed 241 cases for this study; 204 (84.6%) had a visual clearance of stone. Antegrade flow on POD1 was absent in 76 cases (31.5%). A multivariate logistic regression model found that stones located anywhere other than in the renal pelvis (OR 2.63, 95% CI 1.29–5.53; p = 0.01), non-lower pole access (OR 2.81, 95% CI 1.42–5.74; p < 0.01), and concurrent ipsilateral URS (OR 2.17, 95% CI 1.02–4.65; p = 0.05) increased the likelihood of obstruction. BMI, pre-operative stone burden, EBL, and operative time did not affect antegrade flow outcomes.ConclusionConcurrent ipsilateral URS, absence of stones in the renal pelvis, and non-lower pole access are associated with increased likelihood of ureteral obstruction after PCNL. Access location appears to be the strongest predictor. Recognizing these risk factors can be helpful in guiding postoperative tube management.