Stone Characteristics Research Articles

Predictors of follow-up of pediatric stone patients after surgical intervention

We investigated if socioeconomic and demographic factors predict post-surgical follow-up in pediatric stone patients. All patients having kidney stone surgery at a single academic pediatric hospital over a 5 year period (2016-2020) were identified through the use of CPT® codes specific to ureteroscopy, shock wave lithotripsy, and percutaneous nephrolithotomy. Electronic charts were reviewed for patient demographics, stone characteristics, and characteristics of intervention. Unique patients with a scheduled post-operative follow-up office visit following a first time stone surgery were included in the patient cohort (Figure 1). Primary outcome was attendance of a scheduled provider visit within 6 months after surgery. Secondary outcomes included completion of scheduled post-operative imaging and 24-h urine study. Univariable analysis was performed. 195 pediatric patients, a median age of 15.4 years (IQR: 11.34, 17.14) at surgery, were identified. The majority were non-Hispanic white (86.2%) and female (62.1%). Most had undergone ureteroscopy alone (85.6%). Of the 195 patients, 146 (74.9%) attended a post-operative office visit. Indicators of lower socioeconomic status, such as having public insurance and being from a single-parent home, were associated with not attending a scheduled follow-up visit (p<0.01 and p=0.02, respectively). Patients with a pre-operative urology clinic visit were more likely to follow-up with a clinic visit (p=0.02), while those with a larger total stone burden treated were more likely to undergo ordered imaging (p<0.01). We found that indicators of lower socioeconomic status, such as having public insurance status and being in a single-parent household, were associated with lower pediatric follow-up compliance after kidney stone surgery, while patients seen in the urology clinic preoperatively were more likely to attend follow-up. Identifying factors that may predict non-compliance could be used to help at-risk patient populations.

Efficacy Of Retrograde Intra-Renal Surgery For The Treatment Of Large Renal Stone Burdens: A SingleCenter Experience

Background: Retrograde intra-renal surgery (RIRS) has gained popularity as a result of technological advances. Although widely used, the literature on its feasibility for the treatment of large renal stone burdens is limited. This study aimed to assess the efficacy of RIRS for the treatment of large renal stone burdens.. Materials and Methods: Fifty-five patients with stone burdens ≥21 mm and treated with RIRS between November 2019 and October 2021 were evaluated for patient demographics, stone characteristics, and stonefree rates (SFR). Patients were divided into three groups according to stone burdens (21–30 mm, 31–40 mm, and &gt;40 mm). A standard protocol for surgery and chemoprophylaxis was followed. The SFR was determined if there were no residual stones or fragments on follow-up images. All these patients were followed up on for a minimum of 3 months. Results: The mean age of patients was 54.11 ± 11.75 years. The mean stone burden and mean stone density were 32.36 ± 10.20 mm and 966 ± 337 HU, respectively. The mean cumulative endoscopy time was 142.0 ± 74.7 minutes per case. Endoscopy time was longer for stone densities &gt;1000 HU. The overall SFR was 78.2%, with an average of 1.58 sessions of RIRS. SFRs for 21–30 mm, 31–40 mm, and &gt;40 mm groups were 92.9%, 68.8%, and 54.5%, respectively. Conclusion: RIRS is an effective therapeutic option for treating stone burdens of 21–30 mm with overall SFR of 92.9%. When the stone burden exceeds 30 mm, RIRS should only be offered to individuals who are not candidates for other therapeutic options. To better counsel the patient for a staged approach, stone hardness (HU-Hounsfield units) should be considered in surgery planning

Successful endourological treatment for a rare case of atazanavir-induced urinary stones.

Atazanavir, an anti-HIV drug, induces urinary stone formation. We herein report a case of atazanavir-induced bilateral ureteral stones treated with endourological procedures. A 47-year-old male patient on atazanavir was admitted with right flank pain. The patient's serum creatinine level was 3.60 mg/dL. Plain computed tomography showed bilateral hydronephrosis. The left upper ureter was obstructed by a 13 × 12 × 9-mm mass, which had very low CT attenuation values. The lower part of the right ureter was obstructed, but no mass was observed. Given his medical history, we suspected bilateral ureteral obstruction caused by drug-induced stones. A ureteral stent was successfully inserted on the right side, but not on the left side. Thereafter, a bilateral ureteroscopic lithotripsy was performed. Infrared spectrophotometry revealed that the stone component was atazanavir. Understanding the characteristics of these rare drug-induced stones will aid in the proper early diagnosis and treatment.

Experimental Investigation of Knapping Characteristics of Dolerite and Implications for the Interpretation of Middle Stone Age Technologies

ABSTRACT This study examines knapping techniques in the production of stone tools made on dolerite to understand the knapping characteristics of this igneous tool stone. Extensive experimental research exists on the knapping of silica-rich materials like flint, yet studies on materials low in silica remain scarce. Dolerite, an igneous rock composed mainly of plagioclase, feldspar, and pyroxene, has been used during the Palaeolithic globally and the Middle Stone Age (MSA) of Africa specifically. We address two questions: (i.) Does the application of different knapping techniques to dolerite produce artifacts with distinguishable attributes? (ii.) Are these attributes similar to or different from those of flint? Using three direct percussion techniques, we created an experimental reference assemblage on dolerite and conducted a quantitative attribute analysis. Our findings indicate that knapping techniques can be distinguished at the assemblage level, with attributes significantly different from flint, highlighting the need for further studies on diverse lithic materials.

Characteristics of Stones Ageing for Climate Resilience Due to Carbon Lifeform Environment

The aging of stones in response to climate change and the carbon lifeform environment is a fascinating topic that highlights the resilience and adaptability of geological structures to the ever-changing conditions of our planet. Stones, as foundational components of the Earth's crust, undergo a complex process of weathering, erosion, and transformation in the face of environmental challenges such as climate change and the presence of carbon-based lifeforms. In this essay, we will explore the key characteristics of how stones age in response to these factors and the implications for climate resilience.

True-triaxial strength characteristics of cement stone subjected to sulfuric acid corrosion: An experimental and theoretical study

True triaxial tests were conducted to investigate the effect of sulfuric acid corrosion on the true triaxial strength of cement stone under different acid immersion times, including the common loading path and novel loading path with constant Lode angle. The chemical composition and microstructure of cement stone under different acid immersion times (0, 7, 14, and 28 d) were examined via X-ray diffraction and scanning electron microscopy. As the duration of acid immersion increases, the concentrations of portlandite (Ca(OH)2) and calcium silicate hydrate (C-S-H) within the cement stone exhibit a gradual decline, while the presence of calcium sulfate (CaSO4) progressively rises. The microstructure of the cement stone was primarily affected by two factors: the damaging and strengthening effects of sulfuric acid and CaSO4, respectively. The damaging effects of the acid were dominant for days 0–14 of immersion, with continuous increase in microstructure damage. Subsequently, the strengthening effect of CaSO4 became apparent for days 14–28 of immersion, with continuous improvement in microstructure integrity. Consequently, the strength of cement stone exhibited a diminishing trend during the initial immersion period of 0–14 days, followed by an enhancement in strength from 14 to 28 days of immersion. Furthermore, a three-dimensional strength criterion was proposed by combining the Hoek–Brown and Matsuoka–Nakai criteria. The failure envelope first shrank and then expanded with increasing immersion time, accurately describing the variation in strength in the three-dimensional principal stress space.

Regional differences in morphological characteristics of gall stones in children and adolescent in India- an observational multicentre study

Regional differences in morphological characteristics of gall stones in children and adolescent in India- an observational multicentre study

Morphological characteristics of gall stones in children in India- an observational study

Morphological characteristics of gall stones in children in India- an observational study

Validation of stone-kidney size score to predict outcome and complications of pediatric percutaneous nephrolithotomy

The prevelance of urinary system stone disease in children is emphasizing the need for minimally invasive treatments to decrease morbidity and recurrence risk. Percutaneous nephrolithotomy (PCNL) has emerged as a preferred approach for pediatric patients with complex stones due to its minimally invasive nature, including miniaturized and vacuum-assisted access sheaths, advanced laser technology and tubeless and outpatient procedures. However, adult scoring systems have proven ineffective in predicting success and complications in pediatric PCNL. This highlights the need for specialized scoring systems, such as the Stone-Kidney Size (SKS) scoring system, tailored to pediatric patients and will be evaluated in our study for its association with the stone-free rate (SFR) and complications. The data of 144 patients aged <17 years who had undergone PCNL between January 2008 and December 2019 were evaluated retrospectively. Demographics, stone characteristics, perioperative/postoperative outcomes were recorded for each patient. The SKS scoring system comprises the stone kidney index (SKI) and the number of stones, assigns one or two points based on single or multiple stones and an SKI value of <0.3 or ≥0.3, respectively. The SKI is computed by dividing the stone's longest axis by the kidney's longest axis. Residual stones less than 4mm on non-contrast computed tomography are considered clinically insignificant residual fragments (CIRFs). Stone-free and CIRF patients were considered successful results. The relationship between the SKS scoring system and SFR, success, and complication rates after surgery was investigated. Statistical analyses were conducted using SPSS 22.0 software. The SFR was 67.36% and 74.31% when CIRF patients were included, respectively, with a complication rate of 27%. In multivariate analysis, stone treatment history, stone burden, and SKS score were statistically significantly associated with SFR (p<0.001, p=0.032, p<0.001, respectively). Furthermore, the SKS score was the only variable that showed a statistically significant relationship with success. No significant association was found between SKS score and complications (p=0.342). Our study demonstrates a relationship between the SKS scoring system and SFR in pediatric PCNL patients. However, shortcomings have been observed in its capacity to accurately predict post-PCNL complications. Despite being a retrospective analysis and having a single-center design, our study externally validates the relationship between the SKS scoring system and SFR after pediatric PCNL. The SKS scoring system is associated with SFR in pediatric patients undergoing PCNL; however, this relationship has not been established for complications.

Safety and Efficacy of Tubeless Percutaneous Nephrolithotomy: A Prospective Randomized Study

Background: Urinary lithiasis, or kidney stone disease, is a common and longstanding health issue characterized by significant morbidity and recurrence. Despite advancements in treatment modalities, managing large or complex renal stones continues to pose challenges. The evolution of surgical techniques, such as percutaneous nephrolithotomy (PCNL), has significantly impacted the management of kidney stones. This study aims to evaluate the safety and efficacy of tubeless PCNL compared to conventional PCNL in patients with renal and upper ureteric stones. Methods: A prospective randomized study was conducted at the Urology and Nephrology University Hospital, Assiut University, Egypt, from September 2016 to September 2019. The study included 60 patients who met the inclusion criteria and were randomly assigned into two groups: Group 1 (conventional PCNL) and Group 2 (tubeless PCNL). Postoperative outcomes, including pain scores, fever, blood loss, urinary leakage, length of hospitalization, need for re-hospitalization, and stone-free rates, were evaluated. Statistical analyses were performed using SPSS version 20.0, with a p-value of less than 0.05 considered statistically significant. Results: A total of 60 patients were included in the final analysis, equally divided into two groups. There were no statistically significant differences between the groups regarding demographic data, stone characteristics, hemoglobin levels, creatinine levels, or blood loss. However, the duration of surgery was significantly longer in the tubeless group (Group 2) compared to the conventional group (Group 1) (P-value = 0.034). Both groups achieved comparable stone-free rates with no significant differences in postoperative complications. Conclusion: Tubeless PCNL is a safe and effective alternative to conventional PCNL for managing renal and ureteral stones, with comparable outcomes in terms of blood loss, creatinine, and hemoglobin levels. The main advantage of tubeless PCNL is the potential for reduced postoperative discomfort and quicker recovery, although it requires a longer operative time. These findings support the use of tubeless PCNL as a viable option in appropriately selected patients, with implications for improving patient outcomes and reducing healthcare costs associated with kidney stone management.

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.

Extreme Percutaneous Nephrolithotomy: A Case Series of Procedures Requiring Five or More Access Tracts.

Introduction: Percutaneous nephrolithotomy (PCNL) remains the gold standard treatment for patients with complete staghorn stones, for which multiple access tracts may be required. In this study, we describe a series of patients undergoing PCNL with a minimum of five dilated access tracts. Materials and Methods: We performed a multi-institutional retrospective review of 10 patients with complete staghorn stones who underwent PCNL requiring five or more access tracts. We recorded patient demographics, stone characteristics postoperative complications, and stone-free rates (SFRs). The primary endpoint was any postoperative complication. Secondary endpoints included SFR, operative time, and length of stay. SFR was defined as absence of stones or residual fragments <4 mm. Results: A total of 10 patients from two institutions were included. Access tract number ranged from 5 to 11, and median stone volume was 233,042 mm3. Seven patients (70%) experienced postoperative complications, ranging from Clavien II to IVa. Three patients (30%) required blood transfusions. Median operative time was 312 minutes ranging from 180 to 560 minutes. Five patients (50%) were stone-free after the initial procedure. Of those with residual fragments, 4 (40%) required reoperation to be rendered stone-free. Median length of stay was 2.5 days, with a range of 1-6 days. Conclusion: To our knowledge, this is the largest series of patients undergoing PCNL with five or more access tracts reported to date. This study confirms that PCNL with five or more tracts is feasible and relatively safe, albeit with a high rate of complications in the immediate postoperative period.

Relationship between stone volume, average CT value and operation time and efficiency before ureteral soft lens laser lithotripsy.

Soft ureteroscopic holmium laser lithotripsy is becoming increasingly popular as the preferred method for treating mid-to-lower ureteral stones. Studies have indicated that the size, composition, hardness, and fragility of the stones can impact the treatment's effectiveness. To explore the relationship between stone volume, average CT value and operation time and efficiency before ureteral soft lens laser lithotripsy. Our study on 126 patients undergoing ureteroscopic holmium laser lithotripsy for ureteral calculi from May 2020 to January 2022 categorized them into groups based on stone volume and CT value. We compared surgical outcomes and analyzed correlations between stone characteristics, operation parameters, and stone clearance rate to identify independent risk factors influencing treatment efficacy. Group A demonstrated significantly shorter operation durations and lower blood loss compared to Group B, along with higher single stone clearance rates and fewer postoperative complications. Similarly, Group C exhibited shorter operation times, reduced blood loss, higher stone clearance rates, and lower complication rates than Group D. Preoperative stone volume and CT value correlated positively with operation time and stone clearance rate, with both factors identified as independent risk factors affecting ureteral stone clearance following holmium laser lithotripsy. The stone volume and average CT value before ureteral soft lens laser lithotripsy show a positive correlation with operation time and efficiency, indicating that larger stone volumes and higher CT values lead to slower lithotripsy speeds and reduced operation efficiency. Furthermore, preoperative stone volume and average CT value are identified as independent risk factors for residual stones.

Using ensemble learning and hierarchical strategy to predict the outcomes of ESWL for upper ureteral stone treatment

Urinary tract stones are a common and frequently recurring medical issue. Accurately predicting the success rate after surgery can help avoid ineffective medical procedures and reduce unnecessary healthcare costs. This study collected data from patients with upper ureter stones who underwent extracorporeal shock wave lithotripsy, including cases of successful as well as unsuccessful stone removal after the first and second lithotripsy procedures, and constructed prediction systems for the outcomes of the first and second lithotripsy procedures. Features were extracted from three categories of information: patient characteristics, stone characteristics, and extracorporeal shock wave lithotripsy machine data, and additional features were created using Feature Creation. Finally, the impact of features on the models was analyzed using six methods to calculate feature importance. Our prediction model for the first lithotripsy, selected from among 43 methods and seven ensemble learning techniques, achieves an AUC of 0.91. For the second lithotripsy, the AUC reaches 0.76. The results indicate that the detailed and binary information provided by patients regarding their history of stone experiences contributes differently to the predictive accuracy of the first and second lithotripsy procedures. The prediction tool is available at https://predictor.isu.edu.tw/ks.

Ureteric wall thickness as a novel predictor for failed retrograde ureteric stent placement.

We sought to identify predictors of failed retrograde ureteric stent (FRS) placement in the setting of obstructing ureteric calculi. In addition to patient- and stone-specific characteristics, we also considered computed tomography (CT) measures of ureteric wall thickness (UWT), as it has shown clinical potential in predicting outcomes of shockwave lithotripsy, ureteroscopy, and spontaneous stone passage. We performed a retrospective, case-control study comparing patients who had successful retrograde stent (SRS) insertions with those who failed stent placement and ultimately required nephrostomy tube (NT) insertion (2013-2019). Patients were identified using administrative data from a shared electronic medical record (capturing all urology patients in our geographic area) and a prospective database capturing all institutional interventional radiology procedures. Patient demographics, as well as clinical and stone characteristics, were then collected, and imaging manually reviewed. Statistical analysis was performed using univariate and multivariate logistic regression analysis in collaboration with a statistician. A total of 109 patients met inclusion for analysis (34 FRS, 75 SRS). The most common indication for stent insertion included sepsis (79%). On multivariate analysis, both acute kidney injury as primary indication for stent insertion (odds ratio [OR ] 9.16, 95% confidence interval [CI] 1.91-44.00, p=0.006) and UWT (OR 0.34, 95% CI 0.15-0.74, p=0.007) were found to be significantly associated with FRS placement. A receiver operator characteristic curve analysis demonstrates an optimal UWT cutoff of 3.2 mm (sensitivity 60.6%, specificity 83.3%). Elevated UWT and acute kidney injury as an indication for urgent urinary decompression in the setting of obstructing ureteric stones are predictive of FRS placement. These patients may benefit from upfront nephrostomy tube insertion.

CT-based radiomics for predicting success of shock wave lithotripsy in ureteral stones larger than 1cm.

This study aims to investigate the predictive value of CT-based radiomics in determining the success of extracorporeal shock wave lithotripsy (SWL) treatment for ureteral stones larger than 10mm in adult patients. A total of 301 eligible patients (165/136 successful/unsuccessful) who underwent SWL were retrospectively evaluated and divided into a training cohort (n = 241) and a test cohort (n = 60) following an 8:2 ratio. Univariate analysis was performed to assess clinical characteristics for constructing a nomogram. Radiomics and conventional radiological characteristics of stones were evaluated. Following feature selection, radiomics and radiological models were constructed using logistic regression (LR), support vector machine (SVM), random forest (RF), K nearest neighbor (KNN), and XGBoost. The models' performance was compared using metrics such as the area under the receiver operating characteristic curve (AUC), precision, recall, accuracy, and F1 score. Finally, a nomogram was created incorporating the best image model signature and clinical predictors. The SVM-based radiomics model showed superior predictive performance in both training and test cohorts (AUC: 0.956, 0.891, respectively). The nomogram, which combined SVM-based radiomics signature with proximal ureter diameter (PUD), demonstrated further improved predictive performance in the test cohort (AUC: 0.891 vs. 0.939, P = 0.166). Integration of CT-derived radiomics and PUD showed excellent ability to predict SWL treatment success in patients with ureteral stones larger than 10mm, providing a promising approach for clinical decision-making.

Endourological society fellowship program: a real contribution to improve surgical outcomes of stone patients treated with ureteroscopy.

We assessed the impact of the one-year endourological society fellowship program (ESFP) on the achievement of optimal surgical outcomes (OSO) in stone patients treated with ureteroscopy (URS). We identified 303 stone patients treated with URS from January 2018 to June 2022 by five experienced surgeons (ES). Of those, two attended ESFP. OSO was defined as the presence of residual fragments ≤ 4mm at 1-month post-operative imaging (Ultrasound + X - Ray or CT scan). Descriptive statistics explored patients' characteristics and the rate of OSO according to the attendance of ESFP. Uni- and multivariate logistic regression analyses (UVA and MVA) tested the impact of stone characteristics, surgical data, ESFP, and imaging technique on the rate of OSO. The LOWESS curve explored the graphical association between stone size and the multivariable-adjusted probability of OSO in the two groups of surgeons. Of 303 patients, 208 (69%) were treated by the two surgeons who attended ESFP. OSO was achieved in 66% and 52% of patients treated by ES with and without ESFP, respectively (p = 0.01). At UVA, ESFP (OR = 1.78; 95% CI = 1.09-2.90), stone diameter (OR = 0.92; 95% CI = 0.88-0.96), stone location (kidney vs. ureter; OR = 0.34; 95% CI = 0.21-0.58), imaging technique (CT scan vs. Ultrasound + X-Ray; OR = 0.28; 95% CI = 0.16-0.47) predicted OSO achievement (all p < 0.05). At MVA analyses, ESFP was associated with OSO (OR = 2.24; 95% CI = 1.29-3.88; p < 0.05), along with the other aforementioned variables. The LOWESS curve showed that the greater the stone size, the greater the difference in OSO in the two groups of surgeons. ESFP positively affects OSO achievement after URS, especially in patients with a high stone burden.

Comparison of conventional percutaneous nephrolithotomy versus endoscopic combined intrarenal surgery in complex renal calculus – Our institutional experience

Background: Complex renal calculi, characterized by their size, location, and composition, pose a significant challenge to urologists due to the potential for complications and the difficulty in achieving complete stone clearance. Conventional percutaneous nephrolithotomy (PCNL) and endoscopic combined intrarenal surgery (ECIRS) are two established techniques for managing these complex renal calculi. Aims and Objectives: The aims and objectives are to compare the effectiveness, safety, and outcomes of PCNL versus ECIRS in managing complex renal calculi in a cohort of 60 cases treated at GMKMCH-Salem. Materials and Methods: A retrospective analysis was conducted on 60 patients with complex renal calculi who underwent either conventional PCNL or ECIRS during a specified period at GMKMCH-Salem. Patient demographics, stone characteristics, procedural details, intraoperative and post-operative parameters, and complications were analyzed and compared between the two treatment groups. Results: The study found that both PCNL and ECIRS techniques were effective in treating complex renal calculi. However, significant differences were observed between the two groups in terms of outcomes. The ECIRS technique exhibited superior outcomes with higher stone clearance rates (P&lt;0.001), shorter operative times (P&lt;0.05), and reduced hospital stays (P&lt;0.05) compared to conventional PCNL. Conclusion: This study demonstrates that ECIRS is a promising alternative to conventional PCNL in the management of complex renal calculi. The ECIRS technique yielded higher stone clearance rates, shorter operative times, and reduced hospital stays, potentially improving patient outcomes and reducing health-care costs. Although our findings show favorable results for ECIRS, the decision between conventional PCNL and ECIRS should be based on individual patient characteristics, surgeon expertise, and resource availability.

Assessment of Factors Responsible for Stone-Free Status After Retrograde Intrarenal Surgery.

Aim The study aimed to evaluate the predictive factors that determined stone-free rate (SFR) after retrograde intrarenal surgery (RIRS). Materials and methods This prospective study was conducted on 183 patients undergoing RIRS for renal stones. Patients were categorized into two groups, depending on stone-free status one month following the procedure. SFRwas defined as the complete absence of stones or stones <4 mm. The parameters studied included patient demographics, presence of hydronephrosis, presence of preoperative double J-stent, abnormal renal anatomy, and stone characteristics (stone burden, stone number, stone density, stone location, lower pole infundibulopelvic angle, and lower pole renal infundibular length (RIL)). Univariate and multivariate analyses were performed to identify risk factors for residual stones. We assessed the predictive ability of the RIRS score and Resorlu-Unsal stone score (RUSS) for evaluating SFR utilizing receiver operating characteristic (ROC) analysis. Results 183 patients were included inthe study with a median age of 51 years. 131 (71.6%) patients were declared stone-free after the procedure. The mean stone size and density were 16.9 SD±7.5 mm and 1038 SD±342 Hounsfield units (HU) respectively. Stone-free patients had lower stone size (14.3 mm vs. 23.6 mm, p<0.01) and stone density (970 HU vs. 1211 HU, p<0.01) compared to non-stone-free patients. Patients with residual stones had steeper lower pole renal infundibulopelvic angle (RIPA) (31.3° vs. 40.7°, p<0.01) and longer RIL(26.6 mm vs. 21.1 mm, p<0.01). Stone multiplicity (p<0.01), lower pole stone location (p<0.01), and renal malformations (p<0.01)were significant influencing factors for residual renal stones after RIRS. Multivariate analysis revealed stone size, stone density (HU), and stone location as independent predictors for SFR after RIRS. Among the scoring systems, the RIRS score had the highest diagnostic accuracy for SFR (area under the curve (AUC): -0.882, 95% CI-0.828-0.936). Conclusion Stone size, stone density (HU), and stone number are important predictors of SFR after RIRS. Lower pole stone location and abnormal renal anatomy play a substantial role in determining SFR after RIRS. In lower pole stones, a long RIL and acute RIPA negatively influence SFR. Additionally, the RIRS score was found to be a better predictor for SFR than the RUSS score.

The Significance of Stone Culture in the Incidence of Sepsis: Results from a Prospective, Multicenter Study on Infections Post Flexible UreteroreNescopy (I-FUN) and Laser Lithotripsy for Renal Stones.

Objective: Sepsis is the most serious complication of flexible ureteroscopy (F-URS) and laser lithotripsy. We assessed the influence of positive stone culture (SC) on major infectious complications (sepsis, septic shock). Methods: This prospective study enrolled adult patients deemed suitable for F-URS and laser lithotripsy from nine centers (January 2022-August 2023). Inclusion criteria were as follows: kidney stone(s), preoperative midstream urine culture (MSUC), stone(s) assessed at computed tomography scan, and SC. Exclusion criteria were as follows: bilateral procedures, ureteral stones, and children. Group 1 included patients with sterile SC. Group 2 included patients with positive SC. Data are presented as median (interquartile range). A multivariable logistic regression analysis was performed to evaluate factors associated with having a positive SC. Results: In total, 293 patients were included. Median age was 51.0 (24) years. There were 167 (57.0%) males. Group 2 included 32 (2.5%) patients. Group 2 patients were significantly older [75.0 (14) vs 51.0 (23) years, p = 0.02]. Stone features were similar. Major infectious complications were higher in Group 2 (15.6% vs 0.4%). One patient died because of sepsis in Group 2. Two out of 6 (33.3%) patients with major infectious complications had the same pathogen in MSUC and SC. In the multivariable regression analysis, diabetes (OR 3.23), symptomatic urinary infections within 3 months before operation (OR 4.82) and preoperative stent/nephrostomy (OR 2.92) were factors significantly associated with higher odds of positive SC. Conclusions: Patients with positive SC have a higher incidence of major infectious complications after F-URS lithotripsy. SC should be performed whenever feasible because there is a poor correlation between MSUC and SC.