Stone Location Research Articles

Development of Prediction Models for Severe Pain and Urinary Symptoms after Ureteroscopy with Ureteral Stent Placement: Results from the STENTS Study and Initial Validation of Pain Interference.

We developed prediction models for severe pain and urinary symptoms after ureteroscopy with ureteral stent placement. The development cohort included 424 adults and adolescents enrolled in the multicenter STENTS prospective cohort study who underwent ureteroscopy with stent placement for urinary stones. The validation cohort was an independent prospective cohort of 115 adults. The outcomes were severe pain intensity and pain interference, measured by PROMIS, and severe urinary symptoms, measured by the Ureteral Stent Symptom Questionnaire. The top quartile of symptoms on postoperative days 1 and 3 were defined as severe. Generalized estimating equation models were used to predict severe symptoms on postoperative days 1, 3, 5, and 7-9 in the development cohort and severe pain interference on days 1 and 7 in the validation cohort. Female sex, younger age, higher body mass index, baseline pain interference and number of chronic pain conditions, renal stone location, and history of anxiety predicted severe pain. In the development cohort, the C-statistics were 0.83 (95% CI 0.80-0.85) for severe pain interference and 0.82 (95% CI 0.79-0.84) for severe pain intensity. A model in which baseline urinary symptoms replaced pain interference had excellent discrimination for severe urinary symptoms (C-statistic 0.83; 95% CI 0.81-0.85). In the validation cohort, the C-statistic was 0.7 for severe pain interference (95% CI 0.54-0.78). Preoperative characteristics accurately predicted severe pain and urinary symptoms after ureteroscopy with stent placement. Upon further validation, these models could guide clinical decisions to improve surgical outcomes.

A 68-Year-Old Male with Giant Urethral Diverticulum Stone

Introduction: Urolithiasis primarily affects the kidneys, ureters, or bladder, but urethral stones are rare, making up less than 1% of all urinary tract stones. Their prevalence is 0.3% to 2%, with a higher incidence in men due to the longer male urethra. Symptoms range from asymptomatic to severe pain, dysuria, and urinary retention, often complicated by fever or renal failure. Urethral diverticulum, a rare malformation, can cause recurrent infections and stone formation. Diagnosis involves imaging, urethrography, and cystourethroscopy, while treatment depends on stone size and location. Delayed diagnosis can lead to significant morbidity. Case Presentation: A 68-year-old male presented to the clinic with a painful lump in the left scrotum, which had progressively enlarged and hardened. He reported experiencing painful, incomplete urination along with right-sided back pain. The patient had a history of similar lumps that had been surgically removed. Upon examination, a tender, hard mass measuring 4x3 cm was found in the left scrotum. Urethrography revealed a solitary opaque stone in the posterior urethra, while post-contrast imaging confirmed diverticulolithiasis in the bulbo-cavernous urethra, leading to stenosis and partial obstruction, confirming urethral obstruction due to stones. Laboratory tests returned normal results. Conclusion: Urethral stones are rare, constituting less than 1% of urinary tract stones, mainly affecting men. Symptoms range from asymptomatic to severe pain, with potential complications like fever and kidney failure. Diagnosis involves imaging, and timely management is crucial to prevent morbidity.

UrologiQ: AI-based accurate detection, measurement and reporting of stones in CT-KUB scans.

Kidney stone disease is becoming increasingly common worldwide, with its prevalence increasing annually across all age groups, races, and geographic regions. This sharp increase may be due to significant changes in dietary habits. Early and accurate detection of kidney stones is crucial for timely intervention and prevention of complications. This article discusses the role of artificial intelligence (AI) in detecting kidney stones and managing surgical treatments. Recent advances in AI techniques have introduced new tools that improve the diagnosis and analysis of medical images. AI can use CT-KUB image data to accurately detect the location of kidney stones and measure their size more efficiently than manual methods. AI-based detection methods ensure greater precision and consistency in stone identification and measurement. These improvements can help doctors plan treatments more effectively, resulting in a higher success rate for patients. Integrating AI into kidney stone detection and analysis significantly improves treatment planning and patient management, leading to better patient outcomes and overall quality of healthcare.

A Feasibility Study on the Efficacy and Safety of a Novel Tip-Flexible Suction Ureteral Access Sheath Combined with Flexible Ureteroscopic Lithotripsy for Treating Kidney Stones ≥30 mm.

Objective: To evaluate the efficacy and safety of a novel tip-flexible suction ureteral access sheath (NTFS-UAS) combined with flexible ureteroscopic lithotripsy (FURS) for treating kidney stones ≥30 mm in a large cohort. Methods: The clinical data of 206 patients with renal calculi ≥30 mm treated by NTFS-UAS combined with FURS from June 2021 to September 2023 were analyzed retrospectively. The outcomes under investigation encompassed demographic information, stone-related characteristics, operative time, stone-free rates (SFRs), and postoperative complications. Results: The median operation duration was 110 minutes (interquartile 84.00-146.25 minutes). Immediate and 1-month SFRs were 83.98% and 85.44%, respectively. Multivariate analysis revealed five risk factors independently affecting stone clearance rate: stone size (≥50 mm, odds ratio [OR] = 3.826, p = 0.039), stone number (multiple: OR = 8.745, p = 0.015), stone location (multiple calyces: OR = 10.371, p = 0.045; lower calyx: OR = 9.615, p = 0.047), severe hydronephrosis (OR = 8.338, p = 0.002), and the Resorlu-Unsal scoring system (RUSS) score (6-7: OR = 10.829, p = 0.009; 4-5: OR = 4.223, p = 0.008). The incidence of Clavien-Dindo grade II-III complication was 5.82%. Positive preoperative urine culture (OR = 9.533, p = 0.012) and RUSS score (6-7: OR = 25.678, p = 0.026; 4-5: OR = 11.444, p = 0.038) were identified as the most important variables that may contribute to the development of high-grade postoperative complications. Conclusion: NFTS-UAS combined with FURS achieved satisfactory outcomes with good efficacy and safety for treating large renal stones ≥30 mm, and it can be utilized as an effective treatment option for patients having contraindications or preference against percutaneous nephrolithotomy. In addition, clinical factors, such as stone size, severe hydronephrosis, positive preoperative urine culture, and RUSS stone score that likely affected the outcomes of NFTS-UAS, should be fully taken into account when the surgeon performing FURS using NFTS-UAS.

Quadruple-D score in the success rate of extracorporeal shock wave lithotripsy of renal stones in pediatric population.

Evaluation of the validity of the Quadruple-D score in the prediction of success in pediatric stone disease. Of the 292 children treated with SWL between 2007 and 2023, a total of 158 children who had adequate follow-up data and evaluated with non-contrast computed tomography before SWL, were included in the study. Parameters were calculated for each of the stone volume (SV), skin-to-stone distance (SSD), stone density (SD) and stone location (SL) variables. Receiver operator characteristic analysis was used to set cut-off values. Quadruple-D scores were calculated, and success rates were determined for each score. Stone-free status was determined as complete clearance after three months of final SWL. The median age of the study group was 8 (range 1 to 16). One hundred and one of the 158 (64%) children had stone-free status. Mean SV, SSD and SD values were significantly higher in SWL failed group than stone-free group after detecting cutoff values of 150 mm3, 6.7 cm, and 540 HU, respectively. Stone-free rates were detected as 19.6%, 24.7%, 37.2%, 76.2%, and 90.2% with the Quadruple-D scores of 0, 1, 2, 3 and 4 points. Quadruple-D scoring system can further improve Triple-D scoring system by adding stone position parameter to clarify SFR with a simple and easy calculation. We believe that the Quadruple-D score will have better clinical significance than the Triple-D scoring system in predicting the success of SWL in children.

Prospective Evaluation of Outcomes and Complications in Ultra-Mini-Percutaneous Nephrolithotomy for Pediatric Nephrolithiasis: A Three-Year Study

Objective: This prospective study aimed to evaluate the outcomes and complications of Ultra-Mini Percutaneous Nephrolithotomy (UM-PCNL) in pediatric patients with renal calculi over a three-year period (2021-2023). We assessed Stone-Free Rates (SFR), operative success and perioperative complications to determine the efficacy and safety of UM-PCNL in children. Methods: Seventy-eight pediatric patients (aged 1-17 years) underwent UM-PCNL for renal calculi larger than 10 mm. Preoperative imaging, including ultrasonography and computed tomography, was utilized to assess stone size and location. Surgical outcomes, including SFR, operative time and the need for second-look procedures, were evaluated. Complications were graded using the Clavien-Dindo classification. Statistical analysis was conducted using SPSS, with a significance threshold of p < 0.05. Results: The mean stone size was 18.2 ± 5.4 mm and the overall SFR after a single UM-PCNL procedure was 78.2%. Clinical success (defined as either stone-free status or clinically insignificant residual fragments) was achieved in 89.7% of patients. The mean operative time was 67 ± 22 minutes. Second-look procedures were required in 11.5% of cases. The overall complication rate was 19.2%, with no major complications (Clavien grade III-V). Minor complications included transient fever (6.4%), hematuria (12.8%) and urinary leakage (5.1%). Conclusion: UM-PCNL is a safe and effective procedure for managing pediatric nephrolithiasis, offering high stone-free rates and low complication risks. The use of smaller instruments reduces renal trauma, bleeding and the need for blood transfusions. These findings support UM-PCNL as a first-line treatment option for larger renal stones in pediatric patients. Further studies with long-term follow-up are recommended to assess recurrence and long-term renal function outcomes.

Novel scoring system for predicting stone-free rate after flexible ureteroscopy lithotripsy.

This study aims to investigate the factors affecting the stone-free rate (SFR) of flexible ureteroscopy and laser lithotripsy (fURSL) for renal stones and establish predictive models by identifying their prognostic factors. We retrospectively examined 252 patients with renal stones who were treated with fURSL between July 2020 and April 2022. We analyzed the relationship between the patient's clinical data (sex, age, and body mass index), stone status (side, size, location, stone/transverse process pixel ratio [STPR], and the CT value of stone [SCTV]), and SFR to determine the relevant factors and analyze their influence. Additionally, a nomogram was constructed based on these prediction results. A total of 252 patients were enrolled based on the inclusion and exclusion criteria. They were reviewed 7, 30, and 90 days postoperatively, with 46, 23, and 10 patients failing to discharge stones, respectively. Univariate Cox proportional hazard regression results revealed that the SFR was correlated with stone location, diameter (D1, diameter of stone measured by computed tomography [CT]; D2, diameter of stone measured by kidney-ureter-bladder abdominal radiography), SCTV, STPR, and operation time. Multivariate Cox proportional hazard regression was used to develop 2 predictive models for the SFR. The influencing factors of model 1 included D1, location, and SCTV, whereas those of model 2 were D2, location, and STPR. The results are shown in the nomogram. Receiver operating characteristic curves showed no significant difference between models 1 and 2 (P = .498), indicating that the nomogram was highly predictive. After 1000 resamples and internal self-validation, the C-indices of models 1 and 2 were 0.924 and 0.895, respectively, showing that the stone clearance predicted by the nomogram matched the actual situation. Stone location, size, and density (SCTV and STPR) were significant predictors of SFR after fURSL. The scoring system based on these factors may be used to guide optimal treatment strategy selection.

Impacts of clinical backgrounds and intervention strategies on duration of intravenous antibiotics treatments in patients diagnosed with calculous pyelonephritis: A single-center retrospective study

ObjectivesThere are limited information that need to do appropriate treatment including duration of antibiotic treatments, timing of urinary drainage and pathogenesis of bacteria in calculous pyelonephritis. In the present study, we investigated real-world data on clinical features and succeeded treatment strategies in calculous pyelonephritis cases in our hospital, then, aimed to make predictive model estimating duration of intravenous antibiotics treatment. MethodsParticipants were 163 consecutive patients diagnosed with calculous pyelonephritis who underwent antibiotics treatments between 2017 and 2023 in our in-patients’ clinic. Candidates for explanatory variables that may affect duration of antibiotic treatments were age, gender, body mass index, stone location, stone size, septic status, blood culture, urine drainage, indwelling urethral catheter, diabetes mellitus and steroid intake. ResultsDuration of intravenous antibiotics treatment was 6 days in median (IQR: 4–8 days). Indwelling DJ stent or percutaneous nephrostomy were undergone in 74 (45.4 %) patients. Multiple regression analysis revealed that gender, age, indwelling urethral catheter, septic status and management of urine drainage independently affected essential duration of intravenous antibiotics treatment and regression coefficient estimates of those factors respectively were 0.998, 0.890, 2.487, 1.462, 1.293 with constant of 2.464. ConclusionsOur preliminary multiple regression models for predicting duration of intravenous antibiotics treatment may be useful to judge the timing of changing treatment strategies for patients who would not improve at around estimated intravenous antibiotics treatment periods. If vital signs were stable, it may be acceptable to judge urine drainage from above the urinary stone at around two days after intravenous antibiotic treatments.

Development of a novel difficulty scoring system for laparoscopic liver resection procedure in patients with intrahepatic duct stones.

For intrahepatic duct (IHD) stones, laparoscopic liver resection (LLR) is currently a reliable treatment. However, the current LLR difficulty scoring system (DSS) is only available for patients with hepatocellular carcinoma. To explore the development of a DSS for IHD stone patients with LLR and the validation of its reliability. We used clinical data from 80 patients who received LLR for IHD stones. Forty-six of these patients were used in multiple linear regression to construct a scoring system. Another 34 patients from different centers were used as external validation. The completeness of our DSS was then evaluated in patients with varying degrees of surgical difficulty based on documented surgical outcomes in the study group of patients. The following five predictors were ultimately included and scored by calculating the weighted contribution of each factor to the prediction of operative time in the training cohort: Location of stones, number of stones ≥ 3, stones located in the bile ducts of several grades, previous biliary surgery less than twice, distal bile duct atrophy. Subsequently, the data set was validated using a DSS developed from the variables. The following variables were identified as statistically significant in external validation: Operative time, blood loss, intraoperative transfusion, postoperative alanine aminotransferase, and Clavien-Dindo grading ≥ 3. These variables demonstrated statistically significant differences in patients with three or more grades. Patients with IHD stones have varying degrees of surgical difficulty, and the newly developed DSS can be validated with external data to effectively predict risks and complications after LLR surgery.

The efficacy and safety of three different single-use ureteroscopes in retrograde intrarenal surgery: a comparative analysis of a single surgeon's experience in a single center.

To evaluate and compare the clinical results of different single-use flexible ureteroscopes (su-fURS) used in retrograde intrarenal surgery (RIRS). RIRS cases performed identically by an experienced surgeon between 2022 and 2023 in a single center were retrospectively analyzed. These surgeries were performed with three su-fURS (Redpine RP-U-C12, Hugemed HU30, and Pusen Uscope 3022A). In the study, the age, gender, body mass index, and Charlson comorbidity index of the patients were compared, along with their clinical details, such as the stone size, volume, density, location, and history of hydronephrosis or a double J stent or SWL. Operation time, stone-free rates (SFR), perioperative and postoperative complications, and hospitalization times were also compared. The study included 208 patients. Pusen had 63 cases, Hugemed had 62, and Redpine had 83. The comparison of the patient's demographic and clinical properties with stone-related variables was similar between the groups. The SFR was similar between the groups (p = 0.056). Perioperative, postoperative, and total complication rates and the need for a second intervention showed no significant differences among the three groups (p = 0.324, 0.088, 0.061, and 0.052, respectively). In the first study comparing the clinical results of cases in which different su-fURS were used, no difference was observed in surgical outcomes and complications, even though the technical features of these devices were different. Urologists should select su-fURS based on clinical requirements, financial constraints, and personal experiences.

Clinical Significance of Perinephric Fluid Collection in Patients with Renal Colic and Urolithiasis: A Retrospective Analysis

Background: Perinephric fluid is commonly identified in patients with renal colic and urolithiasis, especially in cases associated with hydronephrosis. However, its clinical relevance, particularly its impact on treatment decisions and prognosis, is not well established. Methods: This retrospective, single-center study included adult patients who presented to the emergency department (ED) with suspected renal colic between January 2021 and October 2023. Patients underwent ultrasound evaluations, which were analyzed for perinephric fluid, hydronephrosis, stone size, and stone location. Data on patient demographics, laboratory results, and clinical outcomes, including the need for urological interventions, were also collected and analyzed. Multivariate logistic regression was used to assess factors associated with perinephric fluid presence. Results: Of the 509 patients included, 200 (39.3%) had perinephric fluid. Hydronephrosis was significantly associated with perinephric fluid (OR: 4.14, p = 0.007), as were stones located in the proximal (OR: 3.06, p = 0.003) and distal ureter (OR: 2.31, p = 0.018). However, sonographic perinephric fluid did not significantly affect the likelihood of urological intervention, in-hospital complications, sepsis, acute kidney injury (AKI), acute kidney disease (AKD), and prolonged hospital stay. Conclusions: Perinephric fluid is a common finding in patients with renal colic and urolithiasis, particularly in cases involving hydronephrosis and ureteral stones. However, despite its prevalence, sonographic perinephric fluid was not significantly associated with the need for urological intervention, longer hospital stays, or worse clinical outcomes. Further prospective studies are required to clarify its clinical implications fully.

Evaluation of Optical Tracking to Distinguish Surgeon Experience During Endoscopic Stone Surgery.

Introduction and Objectives: Optical tracking (OT) has shown potential in assessing surgical skill but has yet to be evaluated for endoscopic urologic surgery. We sought to evaluate the potential for OT to distinguish expert and trainee surgeons during flexible ureteroscopy (fURS) for kidney stone treatment in both simulated and live surgical settings. Methods: We performed OT analysis of six surgeons performing stone localization during fURS in two settings. In the first setting, surgeons were tasked with fiducial localization in three separate kidney phantoms during fURS. In the second setting, surgeons performed stone localization via fURS in five separate patients. Surgeons were categorized as "expert" (n = 3, endourologist, average case volume of >100 fURS per year) or trainee (n = 3, trainee, <100 fURS per year). OT metrics were recorded for both settings using the Microsoft HoloLens 2© as the surgeons viewed the surgical monitor during fURS. Standard OT metrics of experts and trainees were compared, and included: area of eye gaze movement, gaze distance traveled, number of gaze fixation points, percentage of gaze fixation dwell time, and number of saccades. Results: In the simulated setting, the average time for stone localization was greater for trainees compared to experts (318 seconds vs 52 seconds, p < 0.01). Additionally, the mean area of eye gaze movements with area of interest (AOI) was greater for trainees compared to experts (1430 cm2 vs 1060 cm2, p < 0.01). The total gaze distance traveled was also greater for trainees compared to experts (1480 cm vs 730 cm, p < 0.01). In the live surgical setting, average time for stone localization was similar for trainees and experts (74 seconds vs 51 seconds, p = 0.05). The total area of eye gaze movements in AOI was greater for trainees compared to experts (700 cm2 vs 30 cm2, p < 0.01). Additionally, the total gaze distance traveled was greater for trainees compared to experts (14,000 cm vs 680 cm, p < 0.01). This suggests more varied and less point specific concentration on the surgical screen by trainees. There was no difference in percentage of gaze fixation dwell time and number of saccades between experts and trainees in either setting. Conclusions: OT analysis can objectively distinguish surgical experience between experts and trainee surgeons performing fURS in both simulated and live surgical settings. These findings may play a role in future surgical training and skills assessment.

Robotic pyelolithotomy for the treatment of large renal stones: a single-center experience over seven years.

Urolithiasis prevalence varies globally between 1-20%, influenced by regional factors. Robotic pyelolithotomy (RPL) presents an interesting alternative to PCNL, considered the gold standard for symptomatic stones smaller than 20 mm, as it carries a risk of significant complications. However, studies on RPL are limited, especially in anatomically complex cases, where RPL proves to be particularly useful. The study aims to update and review outcomes of RPL in a high-volume robotic center. A retrospective analysis of 153 patients treated with RPL for staghorn kidney stones at a single center from February 2016 to December 2023 was conducted. Data including demographics, preoperative renal function, stone characteristics, operative and postoperative outcomes, and costs were collected. Stone-free rates (SFR) and complications were assessed at follow-up intervals up to 12 months post-surgery. The study showed an initial 3-month stone-free rate (SFR) of 93.5%, which decreased to 83.5% at 12-months. This trend may reflect new stone formation rather than procedure failure. Sub-analysis revealed a significant difference in SFR between patients with pelvic and pyelocalyceal stones at each follow-up. Multivariate regression analysis identified in the pyelocalyceal group that higher BMI and larger stones were associated with higher failure rates at both 6 and 12 months. RPL is a safe and effective treatment for large renal stones, offering a high SFR and low complication rate. It is particularly beneficial in cases with complex anatomy or requiring concurrent renal procedures. However, patient selection is crucial, considering factors like stone location and size. Further research is needed to compare RPL with other treatment methods.

Does tilt-retrograde intrarenal surgery enhance stone clearance and offer better surgical ergonomics in patients with renal calculi? A prospective randomized control study.

Retrograde intrarenal surgery (RIRS) is the standard treatment for renal calculi. Direct visualization and fragmentation are its major advantages. The variable stone clearance rates and the ergonomic challenges faced by urologists are a few limitations. Table tilt enhances stone clearance and improves surgical ergonomics by facilitating better access to stones and reducing procedural strain. In this prospective study, patients with intrarenal calculi were randomized into standard lithotomy RIRS (S-RIRS) and table-tilted RIRS (T-RIRS) groups. Specified table tilts were suggested for each of the stone locations. The outcomes with regard to stone clearance, operative and lasing time, and ergonomics were studied. About 100 patients were studied, with 50 in each group. The overall operating time and lasing time in the T-RIRS group were less than that in the S-RIRS group (P < 0.001). The complication rates were the same in both groups. Most surgeons felt that the surgical ergonomics was better in the T-RIRS group (P < 0.001). When stone-free status was analyzed, seven patients in the S-RIRS group and one in the T-RIRS group had residual stones. The mean Borg category-ratio 10 (CR-10) scores in the S-RIRS and T-RIRS groups were 4.18 and 2.20, respectively (P < 0.001). This is the first study to document the distinct advantages of T-RIRS and its benefits on surgical ergonomics. T-RIRS resulted in significantly shorter operative and lasing times, particularly for stones in lower calyces. Surgical ergonomics, assessed by the Borg CR-10 scale, were significantly better in the T-RIRS group. T-RIRS should become a standard of care for patients undergoing RIRS.

Patient-Reported Needs in Postoperative Communication After Kidney Stone Surgery.

Patient-centered communication after surgery can enhance patient satisfaction and reduce unplanned clinical contact. However, patient information needs following kidney stone surgery are not well understood, limiting quality improvement efforts. We aimed to characterize patient-reported needs in and preferences for postoperative communication following kidney stone surgery. Patients undergoing common stone procedures were surveyed about the content, volume, and satisfaction with the communication they received after surgery. Patients indicated which information resources they consulted and found most helpful to address their postoperative care questions. Among 52 patients, the majority (75%) identified varying degrees of deficiencies in the communication they received after surgery. Regarding content, respondents were most interested in understanding how their surgery went (90%), the plan for follow-up care (85%), and the specific location of their stone (85%). Regarding volume, respondents consistently indicated interest in intraoperative findings (stone appearance and location) and postoperative care (stent symptoms and location) but the majority did not recall receiving enough information. To address their questions after surgery, respondents most commonly consulted their urologist (71%), discharge paperwork (42%), electronic health record (27%), and the person with whom their urologist spoke after surgery (25%); among these, the majority (54%) reported that their urologist was the single most helpful source of information. Following kidney stone surgery, patients report unmet communication needs related to specific intraoperative findings and follow-up care. Patients indicate high levels of satisfaction with urologist-provided resources. These exploratory findings support quality improvement efforts to optimize delivery of effective, patient-centered communication after surgery.

Risk factors of hematoma after SWL for renal calculi: analysis from RCTs and a literature review.

To identify risk factors of perinephric hematoma following extracorporeal shockwave lithotripsy (SWL) for renal calculi through combined analysis of two randomized controlled trials. This post-hoc analysis included adult patients with solitary renal calculi ranging from 5 to 15mm, treated with SWL between 2016 and 2022. All patients received cross-sectional imaging (either non-contrast computer tomography scan or magnetic resonance imaging) two days post-SWL to assess the presence and severity of perinephric hematoma. Among 573 patients analyzed, 173 (30.9%) developed perinephric hematoma by Day 2 post-SWL. Multivariate logistic regression identified higher total energy delivered (odds ratio [OR] = 1.533, p = 0.003), higher mean stone density (OR = 2.603, p = 0.01), higher maximal stone density (OR = 3.578, p = 0.03), and lower pole stone location (OR = 1.545, p = 0.029) were risk factors for the development of hematoma. Conversely, the stepwise ramping protocol was a protective factor for hematoma formation. (OR = 0.572, p = 0.042). This study elucidates key factors influencing the risk of perinephric hematoma post-SWL, highlighting the importance of procedural adjustments such as the stepwise ramping protocol to reduce complications. These insights call for targeted patient and treatment strategy optimization to enhance SWL safety and efficacy.

Multicentre study comparing outcomes of RIRS using traditional suction ureteral access sheath (SUAS) and flexible and navigable suction UAS (FANS)

Objective: We aim to compare the stone-free rate (SFR), complications, and re-treatment rates in retrograde intrarenal surgery (RIRS) using a traditional suction ureteral access sheath (SUAS) with the more advanced flexible and navigable suction UAS (FANS). Materials and methods: Retrospective analysis was performed on patients who underwent RIRS using SUAS versus FANS across five institutions internationally as part of an audit. We analysed baseline and pre-operative characteristics such as stone location and density, intra-operative characteristics such as type of ureteroscope and laser, laser, and fluoroscopy time, as well as post-operative complications and residual fragments (RFs). Results: A total of 45 patients were included in each arm, with no significant difference in baseline characteristics. The commonest sheath size in the FANS group was 10–12 Fr (64.4%), while 11–13 Fr was preferred in SUAS (73.3%). Despite similar lasers (thulium fibre laser (TFL) and high-power holmium laser with MOSES), stone dusting (48.9%) and popcorning (95.6%) were carried out in FANS with minimal need for baskets (4.4%), while popcorning (64.4%) and basket extraction (40.0%) were required in SUAS. Although FANS had significantly longer operative times (65 minutes versus 55 minutes), it also had significantly higher rates of 100% SFR (80.0% versus 13.3%), and lower rates of clinically significant residual fragment (CSRF) (8.9% versus 53.3%), clinically insignificant residual fragment (CIRF) (11.1% versus 33.3%), and reintervention for CSRF (4.4% versus 37.8%). In addition, minor complications such as intra-operative oozing from mucosa not requiring intervention (8.9% versus 31.1%) and post-operative fever (11.1% versus 40.0%) were less common in FANS. On additional multivariate analysis, FANS was the only significant factor for higher SFR. Discussion and conclusion: The results of our study demonstrate that with its flexible and navigable tip, FANS proves advantageous over SUAS in terms of improving immediate SFR with negligible complications. By navigating the sheath into targeted individual calyces, fragments and dust are more successfully aspirated. FANS can therefore help to achieve the trifecta of high single-stage SFR, minimal minor and no major complications, and negligible reintervention rates. Level of evidence: Not applicable.

External validation of Ito’s nomogram and T.O.HO. scoring system in flexible ureterorenoscopy

PurposeThis study aims to assess stone-free rates after flexible ureterorenoscopy (fURS) using the T.O.HO. (Tallness, Occupied lesion, Hounsfield unit evaluation) scoring system and Ito’s nomogram.Materials and methodsIn the study conducted with 484 patients, the following parameters were analyzed: age, sex, comorbidities, hospitalization, affected side, extracorporeal shock wave lithotripsy (ESWL) history, stone length, stone density, number of stones, location, and presence of hydronephrosis.ResultsMultivariate logistic regression analysis revealed that stone length, stone number, and lower pole stone location were associated with the prediction of stone-free status. The cut-off value for Ito’s score was determined to be 13.5 points, with an AUC of 0.792 (sensitivity, 0.609; specificity, 0.821) and a 95% confidence interval of (0.752–0.832) (Fig. 1). The cutoff for the T.O.HO. score was 6.5 points, with an AUC of 0.744 (sensitivity 0.738, specificity 0.602) and a 95% confidence interval of (0.699–0.789).ConclusionIn conclusion, T.O.HO. scoring system and the Ito’s nomogram are promising tools to predict stone-free status (SFS) after fURS in preoperative evaluation. In addition, the success of scoring systems in predicting SFS preoperatively appears promising and offers a potentially valuable approach.

Retrospective study of ureteral stenosis after holmium laser lithotripsy.

To identify the factors influencing postoperative ureteral stenosis following holmium laser lithotripsy. A retrospective study was conducted of 106 patients who underwent ureteroscopic holmium laser lithotripsy. The effects of variables including stone location, stone size, the duration of surgery, water intake, disease duration, and stone-associated polyps were investigated. Logistic regression analysis revealed significant associations of ureteral stenosis with stone location, stone size, duration of surgery, water intake, disease duration, and stone-associated polyps. Patients with proximal stones, with large stones, who underwent long surgical procedures, who drank a large amount of water, who had long-term disease, and who had stone-related polyps were more likely to develop postoperative ureteral stenosis. Significant perioperative complications of holmium laser lithotripsy are associated with prolonged disease, large ureteral stones, long incarceration periods, and the presence of polyps. Surgeons should consider these risk factors during the preoperative evaluation of patients and surgical planning to minimize the risk of postoperative ureteral stenosis.

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.