Search Results (201)

Background/Objectives: Achieving renal access is a key step in percutaneous nephrolithotomy (PNL), with transpapillary access considered the safest anatomical approach. This prospective pilot study aimed to compare the effectiveness of freehand ultrasound-guided (F-UG) versus fluoroscopy-guided (FG) punctures in achieving anatomically accurate transpapillary access during supine PNL, confirmed by endoscopic visualization. Perioperative and postoperative outcomes were also evaluated. Methods: Forty-three patients undergoing supine PNL for renal pelvic or lower calyceal stones were prospectively enrolled and assigned to either the FG group (n = 23) or F-UG group (n = 20). Following renal access, intraoperative flexible ureteroscopy confirmed the anatomical nature of the puncture (transpapillary vs. nonpapillary). The puncture time, fluoroscopy time, operative time, complications (Clavien–Dindo classification), transfusion requirement, hospital stay, and one-month stone-free rates were recorded. Results: Transpapillary access was achieved in 95.7% of FG cases and 55.0% of F-UG cases (p = 0.003). Radiation exposure was significantly lower in the F-UG group (p < 0.001). Complication (15.0% vs. 0.0%) and transfusion rates (10.0% vs. 0.0%) were higher in the F-UG group but not statistically significant (p = 0.092 and p = 0.210, respectively). Other outcomes, including the operative time, hospital stay, and stone-free rates, were similar between groups. Conclusions: FG puncture is more effective for achieving transpapillary access, while F-UG significantly reduces radiation exposure. The endoscopic confirmation method may provide a reference for future comparative studies on access techniques in PNL. Full article

Nephrolithiasis, predominantly driven by calcium oxalate (CaOx) crystal deposition, poses a significant global health burden due to its high prevalence and recurrence rates and limited preventive/therapeutic options. Recent research has underscored a pivotal role for macrophage polarization in nephrolithiasis pathogenesis. Pro-inflammatory phenotype macrophages exacerbate crystal-induced injury and foster stone formation by amplifying crystal adhesion via an NF-κB–IL-1β positive-feedback axis that sustains ROS generation and NLRP3 inflammasome activation, whereas anti-inflammatory phenotype macrophages facilitate crystal clearance and tissue repair. We have summarized the research on treating nephrolithiasis and related renal injury by targeting macrophage polarization in recent years, including therapeutic approaches through pharmacological methods, epigenetic regulation, and advanced biomaterials. At the same time, we have critically evaluated the novel therapeutic strategies for macrophage reprogramming and explored the future development directions of targeting macrophage reprogramming for nephrolithiasis treatment, such as using single-cell/spatial omics to reveal the heterogeneity of macrophages in the stone microenvironment, chimeric antigen receptor macrophages (CAR-Ms) as a potential therapy for specific crystal phagocytosis in certain areas, and multi-omics integration to address inter-patient immune differences. This review highlights that macrophage reprogramming is a transformative frontier in nephrolithiasis management and underscores the need for further research to translate these molecular insights into effective clinical applications. Full article

Aim: This study aimed to evaluate the potential impact of stone characteristics, patient factors, and upper tract anatomical parameters in the prediction of residual fragments (RFs) following the flexible ureteroscopic (fURS) management of renal stones. Patients and Methods: Between June 2023 and July 2024, a total of 104 cases underwent fURS for the minimally invasive management of medium-sized renal stones (10–25 mm), and 28 cases presenting with RFs 3 months after these procedures were included for further evaluation. In addition to the assessment of patient-related factors, non-contrast computed tomography (NCCT) was performed in all cases in an attempt to assess specific stone characteristics and upper tract anatomical parameters in detail during the 3-month follow-up period. Results: An evaluation of our findings indicated that, among the evaluated parameters, a higher degree of hydronephrosis (>Grade 2), a larger stone size (>15 mm), and the presence of multiple stones were found to affect the presence of RFs significantly (p = 0.020, p = 0.012, and p = 0.040, respectively). On the other hand, although the analysis of other parameters such as patient gender, stone side, stone hardness, and the use of an access sheath with univariate regression demonstrated potential correlations, none of these parameters demonstrated a significant impact when analyzed using backward logistic regression. Logistic regression revealed that Grade 2 hydronephrosis (OR = 18.3, p = 0.020), stone size > 15 mm (OR = 7.0, p = 0.012), and multiple stones (OR = 3.7, p = 0.040) significantly increased the risk of residual fragments following fURS. Conclusions: In light of our findings and published data, we can conclude that endourologists should consider the likelihood of RFs’ presence after successful stone disintegration with fURS. A detailed evaluation of the relevant factors revealed that patients with larger stones, higher degrees of hydronephrosis, and multiple calculi may carry the risk of residual fragments after these procedures. Thus, the utilization of such reliable predictive parameters may aid in selecting optimal stone removal strategies and planning subsequent interventions in the rational management of RFs. Full article

Background/Objectives: Predicting kidney stone recurrence after active stone treatment remains challenging due to its multifactorial nature. Artificial intelligence, particularly machine learning, provides new methods for identifying hidden patterns in high-dimensional clinical data. We conducted a study applying machine learning to identify key predictors of recurrence following endoscopic combined intrarenal surgery (ECIRS) in patients with calcium stones. Methods: This retrospective cohort analysis included 72 patients with calcium stones who underwent ECIRS between June 2019 and May 2022 and achieved a complete stone-free status on postoperative CT. Patients were followed for two years, with recurrence assessed through protocolized imaging. We collected 235 variables, including clinical data, 24 h urine collections, stone composition, imaging features, and perioperative findings. Several machine learning models were developed, and SHapley Additive exPlanations (SHAP) analysis identified features associated with recurrence. Results: Within two years, 29 of 72 patients (40.3%) experienced recurrence. The TabNet model demonstrated the highest predictive accuracy (AUC = 0.89), outperforming traditional machine learning algorithms. SHAP analysis identified urinary oxalate ≥ 25.4 mg/day and hemoglobin (Hb) drop ≥ 0.3 g/dL at 3 months postoperatively as independent predictors, even within normal limits. A simplified TabNet-based model using three key features (oxalate, urine volume, and 3-month ΔHb) maintained a strong performance (AUC = 0.75), supporting its clinical utility. Conclusions: Machine learning enabled the accurate prediction of kidney stone recurrence after ECIRS. The inclusion of 24 h urine data significantly improved the performance. Even patients with “normal” oxalate levels showed increased risk, suggesting current clinical thresholds may require re-evaluation. Full article

Background/Objectives: Urolithiasis is a common disease in Western societies, affecting approximately 10% of the population, and more often men than women. The formation of renal calculi is a complex process, including various compounds and proteins. The aim of this study is to compare differences between the trace element concentrations in male and female renal calculi as well as differences between the trace element concentrations in different stone types. Material and Methods: Renal calculi specimens were obtained during elective nephrolithotripsy procedures. Crystallography of renal calculi was performed using X-ray diffraction; an elemental analysis was performed using Inductively Coupled Plasma–Optical Emission Spectrometry. Statistical analysis was performed to assess the differences in the metal element concentration between men and women. The second part of the analysis measured the differences in the metal element concentration between stones containing calcium phosphate (CaP) and pure calcium oxalate (CaOx) stones. Results: The renal calculi (n = 20) obtained from the male patients had a lower potassium concentration than the calculi (n = 24) from the female patients: 393.4 vs. 792.3 mg/kg, p = 0.007. A comparison of the CaP calculi and CaOx calculi showed a higher zinc concentration (p < 0.001) and potassium concentration (p < 0.001) in the stones containing calcium phosphate. Conclusions: The renal calculi from females had a significantly higher potassium content than those from males. This difference was not correlated with hyperkalemia or the blood potassium levels, suggesting a sex-dependent role of uromodulin in stone formation. The stones containing calcium phosphate exhibited higher zinc and potassium concentrations compared to the pure calcium oxalate stones. The increased presence of zinc and potassium in urine may accelerate the formation of calcium phosphate calculi. Full article

Background and Objectives: This study aimed to evaluate the safety, efficacy and outcomes of ultramini percutaneous nephrolithotomy (UM-PNL) in preschool-aged children with kidney stones. Materials and Methods: A retrospective analysis was conducted on 711 renal units of 676 paediatric patients aged 0–6 years who underwent UM-PNL between April 2014 and July 2024. The children’s demographic data, stone characteristics, operative details and postoperative outcomes were analysed. The procedure was performed using a 9.5 Fr sheath and a 7.5 Fr nephroscope, with laser lithotripsy applied. Postoperative follow-up included imaging and a clinical assessment of complications. Results: The mean patient age was 34.2 months (range: 5–72 months). Haematuria (36.8%) and urinary tract infections (24.5%) were the most common presenting symptoms. The mean stone size was 16.2 mm, and the stone-free rate was 89.2% after the first session, increasing to 96.4% with additional interventions. The mean operative time was 38 min. No major complications were observed; 8.4% of cases had Clavien grade 3b complications, most of which were managed conservatively. Blood transfusion was required in 2.6% of the cases. Conclusions: UM-PNL is a safe and effective treatment method for kidney stones in preschool-aged children, characterized by high stone-free rates and a low risk of complications. With proper patient selection and experienced surgical teams, UM-PNL can be considered a first-line option in paediatric stone management. Full article

Extracorporeal shock wave lithotripsy (ESWL), although a highly effective method for the treatment of kidney stones, can cause significant kidney damage. Since urinary protein composition directly reflects kidney function, proteomic analysis of this fluid may be useful to identify changes in protein levels induced by patient exposure to ESWL as a sign of kidney damage. To this end, we collected urine samples from 80 patients with nephrolithiasis 2 h before and 24 h after exposure to ESWL, which were concentrated and subsequently processed with a commercially available enrichment method to extract low-abundance urinary proteins. These were then separated by 2D electrophoresis and subsequently analyzed by a proteomic approach. A large number of proteins were identified as being related to inflammatory, fibrotic, and antioxidant processes and changes in the levels of some of them were confirmed by Western blot analysis. Therefore, although further experimental confirmation is needed, our results demonstrate that ESWL significantly influences the low urinary protein profile of patients with nephrolithiasis. Notably, among the identified proteins, matrix metalloproteinase 7, alpha1-antitrypsin, and clusterin, as well as dimethyl arginine dimethyl amino hydrolase 2 and ab-hydrolase, may play an important role as putative biomarkers in the monitoring and management of ESWL-induced renal damage. Full article

Background and Objectives: To evaluate the effectiveness and outcomes of supine percutaneous nephrolithotomy (PCNL) using the Barts ‘flank-free’ position and ultrasound-guided puncture, assessing the feasibility of the tubeless technique for discharge within 24 h. Materials and Methods: We conducted a retrospective analysis of 208 patients across 220 renal units who underwent supine PCNL at a tertiary university hospital between May 2019 and December 2024. All procedures were performed by a single surgeon. Patient demographics, stone characteristics, and surgical outcomes were analyzed. The tubeless technique was applied in most cases, and outcomes were assessed in terms of operative time, complication rates, stone-free rates (SFRs), and length of hospital stay. Results: The mean operating time was 50.34 ± 30.80 min. Single-tract PCNL was performed in 94.55% of cases, with the tubeless technique used in 90% of patients. The overall complication rate was 9.55%, with no Clavien–Dindo grade IV–V complications observed. On the first postoperative day, 68.18% of patients were discharged, demonstrating 24 h discharge feasibility. SFR and complication rates aligned with existing literature. Conclusions: The Barts ‘flank-free’ position and ultrasound-guided puncture considerably improved surgical access and safety in supine PCNL. The tubeless technique facilitates faster recovery, making early discharge feasible, even with standard sheath sizes. Further research is warranted to validate these findings and optimize renal stone management outcomes. Full article

Background/Objectives: This study evaluates and compares the surgical outcomes of open pyelolithotomy, laparoscopic pyelolithotomy, and retrograde intrarenal surgery (RIRS) in the management of pelvic ectopic kidney stones. Methods: A retrospective analysis was conducted on 47 adult patients with pelvic ectopic kidney stones who underwent surgery between January 2009 and January 2024. Patients were categorized as open pyelolithotomy (n = 15), laparoscopic pyelolithotomy (n = 14), or RIRS (n = 18). Stone-free (SF) rates were assessed in the early postoperative period (1st or 2nd day), in the 1st month, and in the 3rd month. Demographic data, stone characteristics, operative data, and complications were recorded. Results: RIRS had significantly shorter operative and hospitalization times but a lower SF rate in the 3rd month (44.4%) compared to laparoscopy (92.9%) and open pyelolithotomy (86.7%). Additional procedures were required in 50% of RIRS cases to achieve SF status, while none were needed in the other groups. Complications included three Grade 2 cases (two bleeding; transient creatinine elevation) in open pyelolithotomy, two Grade 2 (urinary leakage; infection) and two Grade 3 cases (conversion to open surgery; trapped stent removal) in laparoscopic pyelolithotomy, and one Grade 2 case (febrile infection) in RIRS. Conclusions: Laparoscopic pyelolithotomy demonstrated the highest efficacy and comparable complication rates; making it the preferred approach for pelvic ectopic kidney stones. Open pyelolithotomy remains a valuable alternative where laparoscopic expertise or resources are limited. Although less invasive, RIRS showed lower efficacy due to the challenging anatomy of pelvic ectopic kidneys. Full article

Background/Objectives: Uric acid is a key metabolic byproduct of purine degradation and plays a dual role in human health. At physiological levels, it acts as an antioxidant, protecting against oxidative stress. However, excessive uric acid can lead to hyperuricemia, contributing to conditions like gout, kidney stones, and cardiovascular diseases. Emerging evidence also links elevated uric acid levels with metabolic disorders, including hypertension and insulin resistance. Understanding its regulation is crucial for preventing associated health complications. Methods: This study, part of the Tlalpan 2020 project, aimed to predict uric acid levels using advanced machine learning algorithms. The dataset included clinical, anthropometric, lifestyle, and nutritional characteristics from a cohort in Mexico City. We applied Boosted Decision Trees (Boosted DTR), eXtreme Gradient Boosting (XGBoost), Categorical Boosting (CatBoost), and Shapley Additive Explanations (SHAP) to identify the most relevant variables associated with hyperuricemia. Feature engineering techniques improved model performance, evaluated using Mean Squared Error (MSE), Root-Mean-Square Error (RMSE), and the coefficient of determination (R²). Results: Our study showed that XGBoost had the highest accuracy for anthropometric and clinical predictors, while CatBoost was the most effective at identifying nutritional risk factors. Distinct predictive profiles were observed between men and women. In men, uric acid levels were primarily influenced by renal function markers, lipid profiles, and hereditary predisposition to hyperuricemia, particularly paternal gout and diabetes. Diets rich in processed meats, high-fructose foods, and sugary drinks showed stronger associations with elevated uric acid levels. In women, metabolic and cardiovascular markers, family history of metabolic disorders, and lifestyle factors such as passive smoking and sleep quality were the main contributors. Additionally, while carbohydrate intake was more strongly associated with uric acid levels in women, fructose and sugary beverages had a greater impact in men. To enhance model robustness, a cross-feature selection approach was applied, integrating top features from multiple models, which further improved predictive accuracy, particularly in gender-specific analyses. Conclusions: These findings provide insights into the metabolic, nutritional characteristics, and lifestyle determinants of uric acid levels, supporting targeted public health strategies for hyperuricemia prevention. Full article

This research investigated the unstudied impact, in 416 cases of stone-induced hydronephrosis detected radiographically in 369 patients, of stone size on the stone’s location in the urinary tract and on the hydronephrosis grade. Most (62.5%) of the hydronephrosis cases were Grade 2; 17.1%, Grade 3; 10.6%, Grade 4; and 9.9%, Grade 1. The mean size of the stones reported in the renal pelvis, pelviureteric junction (PUJ), upper ureter (UU), midureter (MU), lower ureter (LU), and vesicoureteral junction (VUJ) that caused hydronephrosis were 23.03 ± 8.97 mm, 15.56 ± 6.59 mm, 12.91 ± 6.02 mm, 11.05 ± 4.27 mm, 10.41 ± 4.80 mm, and 6.73 ± 3.28 mm, respectively. The mean size of Grade 1-causing stones was 16.63 mm; Grade 2, 11.49 mm; Grade 3, 15.69 mm; and Grade 4, 21.23 mm. The mean stone size significantly decreased from the renal pelvis, through the PUJ, UU, MU, and LU, and down to the VUJ and increased as the hydronephrosis grade increased from Grade 2 to Grade 4. In conclusion, large-size stones were predominantly located in the renal pelvis and PUJ, with few located in the lower ureter, and no large stones reached the VUJ. Small-size stones were mostly located in the VUJ, with only one stone in the PUJ, and no small-size stones were present in the renal pelvis. Large-size stones caused severe hydronephrosis, and small-size stones caused grade 2 hydronephrosis. Increases in stone size decreased its passage rate in the ureter and increased the chance of causing high-grade hydronephrosis. These results alert urologists to adopt faster therapeutic procedures for larger stone sizes to reduce renal damage caused by obstructive uropathy. Full article

Purpose: Percutaneous nephrolithotomy (PCNL) is the gold-standard treatment for large renal calculi. Despite its efficacy, complications can occur. This narrative review aims to classify, manage, and prevent PCNL complications, emphasizing risk factors and strategies to optimize outcomes. Findings: PCNL is a safe and highly effective procedure for the management of renal stones. Risk factors include patient comorbidities, stone complexity, prolonged surgical time, and improper access. Proactive measures, such as accurate imaging, antibiotic prophylaxis, and careful surgical techniques, reduce complication rates. Although certain complications may affect surgical outcomes, most are effectively managed through conservative or minimally invasive approaches. Proficiency in the technique is essential for reducing the risk of complications. Conclusions: Understanding the classification, risk factors, and management of PCNL complications is essential for optimizing patient outcomes. Comprehensive preoperative planning, meticulous surgical technique, and tailored postoperative care are critical for minimizing risks and improving procedural safety. Full article

Kidney stones typically present as renal colic in emergency departments (EDs), where patients experience severe pain and often require parenteral therapy for symptom management. The economic burden associated with managing kidney stones exceeds USD 5 billion annually in the US and accounts for more than a million visits to EDs each year. There is clear evidence emphasizing the need for innovative and alternative pain control options for patients with renal colic. Recent randomized controlled trials suggest that intranasal (IN) and intravenous (IV) ketamine are as effective as parenteral NSAIDs and opioids in treating renal colic. However, the limited studies available show inconsistent results regarding the analgesic effects of ketamine. In this study, we reviewed the mechanism of action of ketamine for kidney stones, its efficacy in treating acute renal colic, and the potential adverse side effects of ketamine treatment. A population, intervention, comparison, and outcome (PICO)-related question was formulated to guide our research inquiry: “What are the effects of IV or IN ketamine, as a single agent or as an adjuvant (I), in adult patients diagnosed with acute renal colic (P) on pain scale scores and adverse side effects (O) compared to NSAIDs and/or opioids (C)?” Full article

Background: Urinary stones (urolithiasis) have been categorized as kidney stones (renal calculus), ureteric stones (ureteral calculus and ureterolith), bladder stones (bladder calculus), and urethral stones (urethral calculus); however, the mechanisms underlying their promotion and related injuries in glomerular and tubular cells remain unclear. Although lifestyle-related diseases (LSRDs) such as hyperglycemia, type 2 diabetic mellitus, non-alcoholic fatty liver disease/non-alcoholic steatohepatitis, and cardiovascular disease are risk factors for urolithiasis, the underlying mechanisms remain unclear. Recently, heat shock protein 90 (HSP90) on the membrane of HK-2 human proximal tubular epithelium cells has been associated with the adhesion of urinary stones and cytotoxicity. Further, HSP90 in human pancreatic and breast cells can be modified by various advanced glycation end-products (AGEs), thus affecting their function. Hypothesis 1: We hypothesized that HSP90s on/in human proximal tubular epithelium cells can be modified by various types of AGEs, and that they may affect their functions and it may be a key to reveal that LSRDs are associated with urolithiasis. Hypothesis 2: We considered the possibility that Japanese traditional medicines for urolithiasis may inhibit AGE generation. Of Choreito and Urocalun (the extract of Quercus salicina Blume/Quercus stenophylla Makino) used in the clinic, Choreito is a Kampo medicine, while Urocalun is a characteristic Japanese traditional medicine. As Urocalun contains quercetin, hesperidin, and p-hydroxy cinnamic acid, which can inhibit AGE generation, we hypothesized that Urocalun may inhibit the generation of AGE-modified HSP90s in human proximal tubular epithelium cells. Full article

Background: Recent findings have highlighted that abnormal energy metabolism is a key feature of autosomal-dominant polycystic kidney disease (ADPKD). Emerging evidence suggests that nutritional ketosis could offer therapeutic benefits, including potentially slowing or even reversing disease progression. This systematic review aims to synthesise the literature on ketogenic interventions to evaluate the impact in ADPKD. Methods: A systematic search was conducted in Medline, Embase, and Scopus using relevant Medical Subject Headings (MeSH) and keywords. Studies assessing ketogenic interventions in the management of ADPKD in both human and animal models were selected for data extraction and analysis. Results: Three animal reports and six human studies were identified. Ketogenic diets (KD) significantly slowed polycystic kidney disease (PKD) progression in rats with improved renal function and reduced cystic areas. There was reduced renal fibrosis and cell proliferation. The supplementation of beta-hydroxybutyrate (BHB) in rats also reduced PKD progression in a dose-dependent manner. Human studies (n = 129) on KD in ADPKD reported consistent body mass index (BMI) reduction across trials, with an average weight loss of ∼4 kg. Improvements in blood pressure were also noted. Ketosis was achieved in varying degrees. Effects on kidney function (eGFR) were beneficial. Results for kidney volume were mixed but most studies were underpowered for this outcome. Lipid profiles showed increases in total cholesterol (∼1 mmol/L) and LDL cholesterol (∼0.4 mmol/L) in most studies. Safety concerns such as “keto flu” symptoms, elevated uric acid levels, and occasional kidney stones were noted. Overall feasibility and adherence to the KD were rated positively by most participants. Conclusions: Human studies are promising; however, they have been limited by small sample sizes and short durations. Larger, long-term trials are needed to assess the efficacy, adherence, and safety of ketogenic diets in people with ADPKD. Full article