Stone Size Research Articles

Predictive value of NCCT quantitative analysis for proximal and middle impacted ureteral stones.

The purpose of the study was to explore the predictive value of preoperative quantitative NCCT analysis for proximal and middle ureteral stone impaction. Data of 128 patients who diagnosed with proximal and middle ureteral stones were analyzed. Stone size, upper diameter of the ureter(D1), lower diameter of the ureter (D2), CT attenuation of the ureter above the stone (HA, 'HU above'), CT attenuation of the ureter below the stone (HB, 'HU below'), CT attenuation values of the stone's proximal segments (C1), CT attenuation values of the stone's distal segments (C2), and ureteral wall thickness(UWT)were recorded. Logistic regression was used to perform univariate and multivariate analyses of the data to determine the independent predictors of proximal and middle ureteral stone impaction. The receiver operating characteristic (ROC) curve was plotted to evaluate the predictive performance. Among the 128 patients, 52 (40.6%) had impacted stones, while 76 (59.4%) did not. Multivariate logistic regression analysis showed that stone size > 9.45mm (OR = 1.372, 95% CI = 1.071-1.756, P = 0.012), UWT > 3.22mm (OR = 4.217, 95% CI = 2.165 ~ 8.213, P < 0.001)、DDR > 2.10 (OR = 4.901, 95% CI = 1.797 ~ 13.365, P = 0.002)and HBA > 1.58 (OR = 5.237,95% CI = 1.502 ~ 18.259, P = 0.009)were independent risk factors for predicting ureteral stone impaction. In conclusion, stone size, UWT, DDR, and HBA show crucial predictive value for impaction of stones.

Changes in blood gas in supine and prone positions in percutaneous stone surgery: does position have any advantage for hemodynamics?

To evaluate whether different positions are advantageous for hemodynamics and respiratory balance in patients undergoing percutaneous nephrolithotomy (PCNL) procedures. Pre- and postoperative arterial blood gas data obtained during spontaneous breathing for 67 prone (Group 1) and 56 supine (Group 2) patients undergoing PCNL were analyzed. Additionally data on all patients' gender, age, body mass index, stone size, access and surgical duration, volume of irrigation fluid, length of hospital stay, requirement for blood transfusion, and residual stones were recorded: There were no differences between the groups in terms of age, stone size, operation time, access time, radiation exposure, transfusion requirements, stone-free rate, and length of hospitalization. A statistically significant pH decrease was observed in both groups in the postoperative period (p = 0.001 and p = 0.001, respectively). There was a statistically significant increase in pCO2 values in both groups in the postoperative period (p = 0.001 and p = 0.024, respectively), and that increase did not differ significantly between the groups (p = 0.624). A statistically significant decrease in pO2 and SpO2 values was observed in both groups in the postoperative period compared to the preoperative period. Again, no statistical difference was observed between the groups for these values. There was a statistically significant decrease in bicarbonate in both groups period (p < 0.001 and p = 0.001, respectively). Hemodynamics and the respiratory balance of the patient are impaired in both prone and supine positions. Neither position is superior to the other in this respect.

Follow-Up Survey for Conservatively Managed Ureteric Stones.

Introduction Currently, there are no agreed-upon investigations and follow-up guidelines for the conservative management of ureteric stones. This study used common themes identified in previous works to investigate whether there is a consensus amongst urology consultants in the United Kingdom. Methods This was a questionnaire-based survey study. An online questionnaire was disseminated nationally to urological consultants practicing in the United Kingdom to explore a range of common factors. The initial sample size was 81 UK-based urological consultants with an interest in endourology and stone surgery. Of the initial 81, 20 participants did not complete the survey and therefore the final sample size was 61. Descriptive analysis was used to analyze the data. Results Our survey found that the main factors influencing the follow-up of conservatively managed ureteric stones were stone size 98% (60), stone location 92% (56), and the degree of altered renal function 79% (48). Regardless of stone size, most participants chose to follow up at 2-4 weeks with asymptomatic patients requiring imaging with discrepancies about the modality. Regarding biochemical markers, most participants only repeated renal function tests if this was deranged on presentation. Calcium and uric acid levels were checked regularly. Diclofenac was the analgesia of choice 93% (55). Regarding the availability of acute ESWL services, over half (59%) were able to offer acute ESWL within the week. The majority offer services at least three or more lists per week. Conclusion Our results demonstrate that there is still no overarching consensus in the follow-up of conservatively managed ureteric stones.Several factors backed by high-level evidence are already consistent across the population of urology consultants and considered "best practice." However, before any all-encompassing national guidelines are formalized, further studies in the form of randomized control trials will be needed to yield high-level evidence.

First Worldwide Multicentric Series of Mini-Ecirs in Children: Outcomes from two Tertiary Endourology Centers.

Introduction: Endoscopic combined intrarenal surgery (ECIRS) is a combination of both retrograde and antegrade approaches for treatment of large or complex renal stones in one procedure, that are currently being treated with multiple tracts or sessions of percutaneous nephrolithotomy, increasing the complications. The aim of our study is to describe the clinical outcomes of Mini-ECIRS in a pediatric population. Material and Methods: A retrospective study was performed in pediatric patients with lithiasis disease treated with mini-ECIRS between 2006 and 2023 in 2 referral centers in Europe. Demographic data, clinical data, stone size and location, laser settings, intraoperative variables, stone-free rate (SFR) and complications were collected. Pearson's chi-squared test, Fisheŕs test and logistic regression, were performed. Results: A total of 32 mini-ECIRS were included. The mean age was 9,8 years, 56.3% girls. The mean size and volume of the stone were 21.5mm and 3298, 2mm3, 53.1% were multiple. Ureteral access sheath was used in 93.8% of the surgeries and only 37.5% had preoperative JJ stent. 53.1% of percutaneous access were with 14 Fr sheath. High power laser was the most frequent energy source for lithotripsy, including thulium fiber laser. The mean operative time was 166,6 minutes. There was one perforation of the collecting system that was managed with JJ stent and in the postoperative period 81.2% of the patients had no complications. Three presented fever, 1 developed urinary sepsis, and 1 required reintervention. The SFR was 75% and the size, volume, hardness, and complexity of the lithiasis, as well as the non-use of lithotripsy in the retrograde approach were statistically significant in decreasing the success of the surgery. Conclusions: ECIRS is a feasible, safe, and efficient procedure in children with complex renal lithiasis, decreasing the number of procedures needed for stone free. Multicenter studies are required to validate these results on a population scale.

Conventional ultrasonography enabled with augmented reality needle guidance for percutaneous kidney access: An innovative methodologies randomized controlled trial.

Successful needle puncture of the renal collecting system is a critical but difficult procedure in percutaneous nephrolithotomy (PCNL). Although fluoroscopy and ultrasound are the standard imaging techniques to guide puncture during PCNL, both have known limitations. To assess the feasibility and safety of a new navigation system for needle puncture in ultrasound-guided PCNL. This study employed a single-center randomized controlled trial (RCT) design to assess the feasibility and safety of a new navigation system for needle puncture in ultrasound-guided PCNL. Conducted between May 2021 and November 2021, the trial utilized computer-generated random numbers for participant allocation to control for selection bias. The trial was executed at the *********, which serves as an academic medical center. All patients who met the inclusion criteria were randomly divided into two groups, with 29 patients in each group. One group underwent PCNL procedures using the new navigation system, while the control group underwent standard ultrasound-guided PCNL procedures. Included patients had renal pelvis or caliceal calculi larger than 2.0cm in diameter or had multiple or staghorn stones. The puncture procedure was performed with the support of real-time ultrasound imaging and visual guidance displayed on the screen. The primary outcome was system feasibility and puncture success rate. Secondary outcomes included puncture time, total surgical time, number of attempts, post-procedure complications, and one-year and three-year stone recurrence rates. Stone clearance was defined by postoperative CT. Descriptive statistics summarized patient demographics, stone size, and location. Independent samples t-tests analyzed puncture time and total surgical time. Chi-square or Fisher's exact tests compared stone clearance, complications, socioeconomic status, renal hydronephrosis, stone location, race, and medical history. Linear regression examined the correlation between BMI and puncture time. Significance was set at P<0.05. For all 58 patients undergoing PCNL, needle punctures of the renal collecting system were completed with a success rate of 100%. The average time from planning the puncture protocol to successful puncture was significantly shorter in the AcuSee guidance system group (3.12min, range 0.2-6.88min) compared to the standard ultrasound-guided group (7.58min, range 5.41-10.68min), representing a reduction of approximately 59%. The total surgical time was also shorter in the AcuSee group for patients with no and mild hydronephrosis (P<0.05). Complication rates were lower in the AcuSee group, with no major complications observed. However, 3 patients in the standard ultrasound-guided group have adverse effects after the PCNL procedure. The one-year stone recurrence rate was significantly lower in the AcuSee group (3.4%) compared to the standard group (24.1%), and the three-year recurrence rate was also lower (6.9% vs. 41.4%). Patient-specific factors such as BMI, renal morphology, and prior surgical history did not significantly affect the performance of the AcuSee system. We report the first clinical application of a new navigation system for needle puncture in ultrasound-guided PCNL. It has been demonstrated that it is feasible and safe compared to the standard ultrasound-guided group in percutaneous renal puncture. This technology provides intuitive and easy-to-use visual guidance, which may facilitate safe, accurate and fast needle puncture of the kidney.

Treatment of Urolithiasis with Thulium Fiber Laser in Fragmentation Mode Using Optimized Pulse Sequences.

Objectives: The super-pulsed thulium fiber laser (SP TFL) is a new alternative to high-power holmium laser for intracorporeal lithotripsy. The SP TFL has shown advantages in dusting regimes, but benefits in fragmentation regimes are less understood. The second-generation SP TFL introduces an advanced fragmentation pulse (AFP) sequence to maximize SP TFL's efficiency in fragmentation. This study evaluates safety and efficacy of the SP TFL fragmentation mode in ureteroscopy (URS) and mini percutaneous nephrolithotomy (mini-PCNL). Materials and Methods: The study was conducted in two phases. Safety of a new AFP was compared ex vivo to standard SP TFL fragmentation settings by measuring the dimensions of wounds created in porcine kidney after laser exposure for 0.5, 1.0, and 2.0 s. The resulting wounds were evaluated histologically using nitro blue tetrazolium chloride (NBTC) stain. In the clinical phase, the second-generation SP TFL was used to fragment and extract ureteral and renal stones in 40 patients using ureteroscopic and percutaneous approaches. The stone size, volume, density, laser-on-time, and total energy were recorded for each patient. In addition, the chemical composition, ablation rate, and ablation efficiency were assessed for each stone treatment. Results: The ex vivo mucosa damage profiles caused by AFP were similar to those caused by regular pulses. In clinical phase, the median volume and density for ureteral stones were 0.4 cm3 and 1029 Hounsfield units (HU), for renal stones 1.3 cm3 and 1113 HU, respectively. Different stone types were crushed into fragments suitable for extraction. The mean AFP energy was 3 J and the average power for ureteral stones was 10.5 W, whereas for renal stones it was 28.5 J and 31 W, respectively. The overall complication rate was low in both groups. Conclusion: ST PFL with AFP capability facilitates effective fragmentation of ureteral and renal stones of any composition during URS and mini-PCNL with minimal complication rates.

Radiological signs of stone impaction add no value in predicting spontaneous stone passage

Stone size and location are key factors in predicting spontaneous stone passage (SSP), but little attention has been paid to the influence of radiological signs of stone impaction (RSSI). This research aims to determine whether RSSI, alongside stone size, can predict SSP and to evaluate the consistency of ureteral wall thickness (UWT) measurements among observers. In this retrospective study, 160 patients with a single upper or middle ureteral stone on acute non-enhanced computed tomography (NCCT) were analysed. Patient data were collected from medical records. Measurements of RSSI, including UWT, ureteral diameters, and average attenuation above and below the stone, were taken on NCCT by four independent readers blind to the outcomes. The cohort consisted of 70% males with an average age of 51 ± 15. SSP occurred in 61% of patients over 20 weeks. The median stone length was 5.7 mm (IQR: 4.5–7.3) and was significantly shorter in patients who passed their stones at short- (4.6 vs. 7.1, p < 0.001) and long-term (4.8 vs. 7.1, p < 0.001) follow-up. For stone length, the area under the receiver operating characteristic curve (AUC) for predicting SSP was 0.90 (CI 0.84–0.96) and only increased to 0.91 (CI 0.85–0.95) when adding ureteral diameters and UWT. Ureteral attenuation did not predict SSP (AUC < 0.5). Interobserver variability for UWT was moderate, with ± 2.0 mm multi-reader limits of agreement (LOA). The results suggest that RSSI do not enhance the predictive value of stone size for SSP. UWT measurements exhibit moderate reliability with significant interobserver variability.

Application of 11/13Fr suctioning ureteral access sheath and 8.55Fr single-use digital flexible ureteroscope in one-stage flexible ureteroscopic lithotripsy: an initial experience of 900 cases.

To report our initial experience of one-stage flexible ureteroscopic lithotripsy(FURL) with 11/13Fr suctioning ureteral access sheath(UAS) and 8.55Fr single-use digital flexible ureteroscope(SDFU) in upper ureteral or renal calculi. We retrospectively collected the clinical data of 900 adult patients with upper ureteral or renal calculi treated by FURL with 11/13Fr suctioning UAS and 8.55Fr SDFU from January 2022 to April 2024. Demographics, peri- and postoperative outcomes were assessed. In all, 40 of 940 cases(4.26%) failed to introduce UAS and required second-stage FURL because of ureterostenosis and were excluded. Mean stones size of the remaining 900 eligible cases was 1.68 ± 0.58cm in greatest diameter. There were 228 cases of upper ureteral stone, 456 cases of renal stone and 216 cases of concomitant ureteral and renal calculi. The mean operation time was 52.20 ± 20.21min and the postoperative hospital stay was 2.87 ± 1.37 days. The stone-free rate of 1 month postoperatively was 89.56% and only 2.44% of patients with residue underwent additional reoperation. The rate of postoperative fever, postoperative pain needing analgesic and slight ureteral mucosal injury were 5.11%, 8.22% and 7.78%, respectively. None of patient suffered from severe complications, such as sepsis or ureteral perforation. It's practical and suitable for the vast majority of adult patients to undergo FURL in single session with 11/13Fr suctioning UAS without preoperative stenting. FURL with 11/13Fr suctioning UAS and 8.55Fr SDFU is feasible, reliable, safe, and efficient in the management of renal stone and upper ureteral stone.

A Grading System for Assessing the Status of the Sphincter of Oddi During Intraoperative Choledochoscopy: A Surgeon's Perspective.

The aim of this study was to establish a simple and practical grading system for evaluating the status of the sphincter of Oddi (SO) during intraoperative choledochoscopy. This system helps identify relevant variables that influence the status of the SO and provides recommendations for preventing stone recurrence. Ninety-three patients were selected retrospectively from a total of 316 patients diagnosed with choledocholithiasis between July 2020 and June 2023. All patients underwent common bile duct (CBD) exploration surgery and intraoperative choledochoscopy. The status of the SO was assessed during choledochoscopy. According to the severity of the condition, the patients were categorized into 4 groups. Data from each group, grades 1, 2, 3, 4, was analyzed statistically. The number of patients in grade 1 was significantly lower than that of the other 3 groups. Except for grade 1, patients in grade 4 exhibited significant differences compared with the other 2 groups in terms of the diameter of the CBD, size of stones, presence of pneumobilia, and history of endoscopic retrograde cholangiopancreatography (ERCP) ( P <0.05). There were no significant differences between the groups in terms of sex, age, liver function, number of stones, history of gastrectomy, cholecystectomy, or CBD exploration. The grading system helps us classify different sphincter functions and better understand the formation of choledocholithiasis by subdividing the status of the SO. Endoscopic sphincterotomy (EST) treatment can easily result in the loss of SO function, which increases the risk of stone recurrence.

Radiological and Hematological Parameters Predicting Success of Medical Expulsive Therapy in Patients With Ureteral Calculus.

Background Urolithiasis, characterized by the formation of stones in the urinary tract, is a common condition with significant morbidity. Medical expulsive therapy (MET) has emerged as a non-invasive treatment modality for facilitating the spontaneous passage of ureteral stones. However, MET success varies widely among individuals, and identifying predictive factors for treatment outcomes is crucial for optimizing patient care. Objective This study aimed to evaluate the predictive role of radiological and hematological parameters in the success of MET for ureteral stones. Methods A prospective observational cohort study was conducted at the Department of Urology, tertiary care center, Patna, involving consecutive patients who underwent MET for ureteral stones. Radiological parameters (stone size, location, and hydronephrosis) and hematological markers (C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio (NLR)) were assessed as predictors of treatment success. Univariate and multivariate logistic regression analyses were performed to identify significant predictors of MET success. Results Among the 156 patients included in the study (mean age: 42 years; range: 18-50 years), radiological parameters, such as smaller stone size (<10 mm) and absence of hydronephrosis, were significantly associated with higher rates of MET success (p<0.05). Lower CRP levels (p<0.001) and NLR (p<0.05) were also predictive of treatment success. Logistic regression analysis confirmed the independent predictive value of these parameters after adjusting for potential confounders. Conclusion Radiological and hematological parameters are valuable predictors of the success of MET for ureteral stones. Incorporating these predictive factors into clinical decision-making can optimize treatment outcomes and minimize unnecessary interventions in patients with a higher likelihood of spontaneous stone passage.

CT-Based Predictors of Spontaneous Ureteral Stone Passage.

To assess CT-scan based parameters, particularly ureteral wall thickness (UWT), in predicting spontaneous ureteral stone passage. Cross-sectional, analytical study. Place and Duration of the Study: Section of Urology, Department of Surgery, The Aga Khan University Hospital, Karachi, Pakistan, from June to November 2023. Patients with symptomatic, single, radio-opaque, unilateral ureteral stones having size ≤10 mm with normal kidney functions, diagnosed by non-contrast CT-scan KUB, and treated by conservative option for four weeks were enrolled. Clinical and radiological predictors for stone passage (SP), including stone size, area, laterality, location, density, degree of hydronephrosis, maximal UWT at the stone site, and ureteral diameter and density above and below the stone, were evaluated. Binary logistic regression analysis was employed to identify predictors of stone passage. Receiver operating characteristic (ROC) curve was used to find the optimal cut-off for UWT. Among 34 eligible patients, 22 (64.7%) passed their stones spontaneously. Patients who passed had smaller stone size and area and lesser UWT. Stone location, laterality, degree of hydronephrosis, stone density, ureteral wall diameter, and density above and below stones were not associated with SP. Multivariate analysis revealed maximum UWT as the independent predictor of SP, with a cut-off of 1.95 mm and an accuracy of 0.94. UWT was the single most convincing factor for the spontaneous passage of ureteral stone in this study. By applying UWT's optimal cut-off value, it might be an extremely significant tool when taking decisions in daily practice. Ureteral wall thickness, Medical expulsive therapy, Non-contrast computed tomography.

Ureteroscopy vs laparoscopic ureterolithotomy for large proximal ureteric stone: a randomised trial.

To compare the outcomes of retrograde flexible ureteroscopy (fURS) with retroperitoneal laparoscopic ureterolithotomy (RLU) for large proximal ureteric stones. A prospective randomised trial was conducted from January 2018 through December 2022 including patients with impacted proximal ureteric stones of 15-25 mm. Patients underwent fURS or RLU. Primary outcome was the stone-free rate. Demographic data, stone features, and complications rates were also compared between groups. A total of 64 patients were enrolled, 32 in each group. The mean impacted stone time was similar between groups, as well as stone size (17 mm) and stone density (>1000 Hounsfield Units). The ureteric stone-free rates between the two groups (93.7% in fURS vs 96.8% in RLU; odds ratio [OR] 0.72, 95% confidence interval [CI] -1.72 to 3.17; P = 0.554), and overall success rates, which take into account residual fragments in the kidney (84.3% in fURS vs 93.7% in RLU; OR 1.02, 95% CI -0.69 to 2.74; P = 0.23), were similar. Operative time was also not statistically significantly different between groups (median 80 vs 82 min; P = 0.101). There was no difference in hospital length of stay. Retropulsion rate was higher with fURS (65.6% vs 3.1%; p < 0.001). Residual hydronephrosis (34.3% each group) and complication rates did no differ according to treatment. Flexible URS and RLU are both highly efficient and present low morbidity for large impacted proximal ureteric stone treatment. RLU is not superior to fURS.

The efficacy of early extracorporeal shockwave lithotripsy for the treatment of 5 to 10 mm upper ureteral stones: An observational study.

This study aimed to determine the effectiveness of extracorporeal shockwave lithotripsy (SWL) performed in the early period (within the first 24 hours). Data of patients who underwent SWL with a diagnosis of unilateral radiopaque 5 to 10 mm upper ureteral stones were retrospectively examined. Patients were divided into 2 groups. Group 1 (early SWL) consisted of patients with SWL performed within 24 hours after the onset of colic pain (<24 hours), while group 2 (deferred SWL) comprised patients with SWL performed 24 hours or more from the onset of pain (≥24 hours). The primary endpoint of the study was planned to determine 1-month SFR in both groups. The secondary endpoint was determined to be the factor affecting SWL success. The mean age of 216 patients (130 men, 86 women) included in this study was 46.5 ± 12.1 years. SFR within 1 month was detected in 175 patients (81%). In the early SWL group, the average number of SWL sessions was fewer (1.26 vs 1.83 P = .026) and the time to the stone-free state was shorter (11 vs 15.4 days P = .044). SFR within 1 month was higher in the early SWL group (85.5% vs 71.8% P = .036). In multivariate analysis, stone size, Hounsfield Units, and early SWL were predictive factors for SWL success. Performing SWL within the first 24 hours is highly effective in patients with symptomatic 5 to 10 mm upper ureteral stones.

Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study

Management of large pediatric kidney calculi (PKC) is challenging. This study aimed to evaluate the efficacy and safety of miniature endoscopic combined intrarenal surgery (mini-ECIRS) for PKC. We retrospectively analyzed mini-ECIRS in 16 pediatric patients undergoing kidney stone treatment between November 2014 and October 2023 to determine its safety, efficacy, and associated outcomes. The median age was 50.50 (interquartile range: 36.75, 84.75) months, and the mean stone size was 21.63 ± 11.65 mm. The stone-free rate was 81.25%. The median decrease in hemoglobin level on the day after surgery was 1.10 (0.80, 1.55), and no patient required a blood transfusion. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Postoperative complications included fever in two patients and difficulty in removing the ureteral stent in one patient. In this cohort, five patients underwent pre-stenting under general anesthesia before mini-ECIRS. Age was significantly lower in the pre-stenting group than in the non-pre-stenting (P < 0.01); however, there were no significant differences in operative time, stone-free rate, total number of general anesthesia procedures, hemoglobin loss, or postoperative hospital stay between the groups. Mini-ECIRS was found to be a safe and efficient treatment method with a high stone removal rate in pediatric patients.

Plant-based therapies for urolithiasis: a systematic review of clinical and preclinical studies.

Urolithiasis, the formation of kidney stones, is a common and severe condition. Despite advances in understanding its pathophysiology, affordable treatment options are needed worldwide. Hence, the interest is in herbal medicines as alternative or supplementary therapy for urinary stone disease. This review explores the use of plant extracts and phytochemicals in preventing and treating urolithiasis. Following PRISMA standards, we systematically reviewed the literature on PubMed/Medline, focusing on herbal items evaluated in in vivo models, in vitro studies, and clinical trials related to nephrolithiasis/urolithiasis. We searched English language publications from January 2021 to December 2023. Studies assessing plant extracts and phytochemicals' therapeutic potential in urolithiasis were included. Data extracted included study design, stone type, plant type, part of plant used, solvent type, main findings, and study references. A total of 64 studies were included. Most studies used ethylene glycol to induce hyperoxaluria and nephrolithiasis in rat models. Various extraction methods were used to extract bioactive compounds from different plant parts. Several plants and phytochemicals, including Alhagi maurorum, Aerva lanata, Dolichos biflorus, Cucumis melo, and quercetin, demonstrated potential effectiveness in reducing stone formation, size, and number. Natural substances offer an alternative or supplementary approach to current treatments, potentially reducing pain and improving the quality of life for urolithiasis patients. However, further research is needed to clarify their mechanisms of action and optimize their therapeutic use. The potential of plant-based therapies in treating urolithiasis is promising, and ongoing research is expected to lead to treatment advancements benefiting patients globally.

Enhanced elastic stability of a topologically disordered crystalline metal–organic framework

By virtue of their open network structures and low densities, metal–organic frameworks (MOFs) are soft materials that exhibit elastic instabilities at low applied stresses. The conventional strategy for improving elastic stability is to increase the connectivity of the underlying MOF network, which necessarily increases the material density and reduces the porosity. Here we demonstrate an alternative paradigm, whereby elastic stability is enhanced in a MOF with an aperiodic network topology. We use a combination of variable-pressure single-crystal X-ray diffraction measurements and coarse-grained lattice-dynamical calculations to interrogate the high-pressure behaviour of the topologically aperiodic system TRUMOF-1, which we compare against that of its ordered congener MOF-5. We show that the topology of the former quenches the elastic instability responsible for pressure-induced framework collapse in the latter, much as irregularity in the shapes and sizes of stones acts to prevent cooperative mechanical failure in drystone walls. Our results establish aperiodicity as a counter-intuitive design motif in engineering the mechanical properties of framework structures that is relevant to MOFs and larger-scale architectures alike.

Safety and efficacy of ultrasound-assisted bedside ureteric stent placement A prospective, single-institution study.

Previous studies have demonstrated the feasibility of bedside placement of ureteric stents; however, they have traditionally required two skilled operators and were associated with some stent malposition especially for proximal ureteric obstruction. We sought to investigate the efficacy and safety of a modified technique for ultrasound-assisted bedside ureteric stent insertion without the presence of a skilled assist. A single institution prospective study was performed from April-August 2023. Indications for stenting included infection, renal insufficiency, or intractable colic. Exclusion criteria included age <18 years, hemodynamic instability, and patients with history of chronic pain. Point-of-care ultrasound (POCUS) was used to confirm wire placement in the kidney and presence of a hydronephrotic drip from a 5 French ureteric catheter was used to confirm placement beyond the level of obstruction. Of 28 patients, all patients underwent successful bedside ureteric stent placement. Mean age was 64.9 years and mean body mass index (BMI) was 33.2. Proximal ureter obstruction was present in 52% of patients and mid/distal obstruction in 48%. In cases with obstructing stones, the mean stone size was 8.1 mm with a range of 4-15 mm. Infection was the indication for stent placement in most patients (71%), followed by pain (4%) and acute kidney injury (AKI) (4%). All patients who underwent successful stent placement had presence of hydronephrotic drip from the ureteric catheter. Ultrasound-assisted bedside ureteric stent insertion without a skilled assist is a safe and feasible option for management of acute ureteral obstruction. Presence of hydronephrotic drip can indicate successful access beyond the level of obstruction as an alternative to POCUS.

Comparison of automated kidney stone size measurement and volumetry in photon counting CT compared to 3rd generation dual energy CT and physically measurements - an ex vivo study.

This ex vivo study aimed to compare a newly developed dual-source photon-counting CT (PCCT) with a 3rd generation dual-source dual-energy CT (DECT) for the detection and measurement (stone lengths and volumetrics) of urinary stones. 143 urinary stones with a known geometry were physically measured and defined as reference values. Next, urinary stones were placed in an anthropomorphic abdomen-model and were scanned with DECT and PCCT. Images were read by two experienced examiners and automatically evaluated using a specific software. DECT and PCCT showed a high sensitivity for manual stone detection of 97.9% and 94.4%, and for automatic detection of 93.0% and 87.4%, respectively. Compared to that uric acid and xanthine stones were recognized slightly worse by DECT and PCCT with manual stone detection (93.3% and 82.2%), and with automatic detection (77.8% and 60.0%). All other stone entities were completely recognized. By comparing the maximum diameter of the reference value and DECT, Pearson-correlation was 0.96 (p < 0.001) for manual and 0.97 (p < 0.001) for automatic measurement, and for PCCT it was 0.94 (p < 0.001) for manual and 0.97 (p < 0.001) for automatic measurements. DECT and PCCT can also reliably determine volume manually and automatically with a Pearson-correlation of 0.99 (p < 0.001), respectively. Both CTs showed comparable results in stone detection, length measurement and volumetry compared to the reference values. Automatic measurement tends to underestimate the maximum diameter. DECT proved to be slightly superior in the recognition of xanthine and uric acid stones.

Risk Factors of Asymptomatic Kidney Stone Passage in Adults with Recurrent Kidney Stones.

Kidney stones are a common health problem and are characterized by a high risk of recurrence. A certain number of kidney stones passed asymptomatically. Data regarding the frequency of asymptomatic spontaneous stone passages are limited. To assess the frequency of asymptomatic spontaneous stone passage and its covariates, we conducted a post-hoc analysis of the prospective randomized NOSTONE trial. All asymptomatic spontaneous stone passages were identified by comparing the total number of kidney stones on low-dose non-contrast CT imaging at the beginning and end of the study, considering symptomatic stone passages and surgical stone removal. The statistical analysis focused on the association of independent variables and the number of asymptomatic spontaneous stone passages using linear regression analyses. Of the 416 randomized patients, 383 with both baseline and end-of-study CT were included in this analysis. The median follow-up period was 35 months, the median patient age was 49 years (IQR:40 - 55), and 20% of the patients were female. A total of 442 stone events occurred in 209 out of 383 (55%) patients: 217 out of 442 (49%) were symptomatic spontaneous stone passages, 67 out of 442 (15%) were surgically removed stones, and 158 out of 442 (36%) were asymptomatic spontaneous stone passages. The median size of asymptomatic stones (2.4 mm; IQR:1.95-3.4) and the size of symptomatic stones (2.15 mm; IQR:1.68-2.79) that passed spontaneously were not significantly different (p=0.37). The number of asymptomatic spontaneous stone passages was significantly associated with a higher number of stones on CT at randomization (P=0.001). Limitations include the lack of data on stone size at the time of passage and overrepresentation of White men. Asymptomatic stone passage was common in patients with recurrent calcium-containing kidney stones. The higher the number of stones at presentation, the more likely it was that a kidney stone would spontaneously pass over time without causing any symptoms.

Factors predicting stone-free rates after retrograde intrarenal surgery for lower pole kidney stones

Introduction: We aimed to investigate the factors impacting stone clearance following retrograde intrarenal surgery (RIRS) for lower pole kidney stones and to determine whether there is a significant relationship between the infundibular pelvic angle (IPA) of the kidney's lower pole and stone fragment clearance. Methods: We retrospectively reviewed patients who underwent flexible ureteroscopy (f-URS) for lower pole renal calculi between December 2020 and July 2023 at our institution. Patient demographics and stone parameters were recorded, including stone size, number, volume, density, and IPA. Intraoperative data, including total operative time, lasing time, type of laser used, and stone composition, were collected and analyzed. All patients underwent a computed tomography (CT) scan at three months followup. We recorded the presence of residual stones and the percentage of stone volume reduction. Patients with a stone size 3 mm were deemed stone-free. All patients were discharged home on the same operative day. Results: A total of 123 patients were included in the study: 71 in the stone-free group (group 1) and 52 in the residual stones group (group 2). On univariate analysis, there were significant differences between the two groups in terms of stone size, IPA, and the type of ureteroscopy used. At three months followup, 96% (24/25) of patients with an IPA &lt;30° had residual stones, compared to 28.6% (28/98) of patients with an IPA &gt;30° (p&lt;0.001). There was no significant difference in the intraoperative or postoperative complications between the two groups. On multivariate analysis, IPA and stone size were the only predictive factors for the presence of residual stones. Twelve patients (23.1%) from group 2 required retreatment. Conclusions: RIRS is an effective treatment option for the management of lower pole kidney stones. IPA, in conjunction with stone size, appears to dictate the stone clearance rates of RIRS for lower pole stones.