Ureteral Access Sheath Research Articles

Multicenter outcome analysis of different sheath sizes for Flexible and Navigable Suction ureteral access sheath (FANS) ureteroscopy: an EAU Endourology collaboration with the global FANS study group.

Flexible and navigable suction ureteral access sheath (FANS) is a potential game changer in flexible ureteroscopy (FURS). The influence of sheath size on outcomes needs research. The primary aim was to analyze 30-day single stage stone free status (SFS), zero fragment rate (ZFR) and complications when using 10/12Fr sheaths vis a vis other sheath sizes. The global FANS research group published the 30-day outcomes in patients who underwent FANS and reasoned this can be a potential game changer. We included 295 patients from this anonymized dataset with division into two groups: Group 1 (Smaller sheath) - 10/12Fr FANS, and Group 2 (Larger sheath) - 11/13Fr or 12/14Fr sheaths. Stone volume was similar between both groups (median 1320 mm3, p = 0.88). Ureteroscopy and total operative time was longer in the smaller sheath group (35 vs. 32min, p = 0.02 and 50 vs. 45min, p = 0.001, respectively). While 30-day computed tomography SFS (100% stone free or single residual fragment ≤ 2mm) were not significantly different (96% vs. 95%, p > 0.99), ZFR (100% stone-free) was better with smaller sheaths (68% vs. 53%, p = 0.02). There was no difference in postoperative complication rates, and no sepsis in both groups. Urologists should consider individualizing appropriate sheath size in normal adult kidneys. Sheath size did not affect complication rates, risk of perioperative injury to the pelvicalyceal system or ureteric injury, but smaller FANS sheaths had similar high SFS. The ZFR with smaller sheaths was better, but this needs to be validated. These smaller sheath outcomes need to be balanced with longer ureteroscopy time, operative time, reach to the lower pole, ease of suction and visibility during lithotripsy. Large volume studies in different types of pelvicalyceal anatomy can determine if indeed smaller FANS is the best choice in FURS.

Analysis of the effectiveness and safety of 7.5 Fr ultra-thin flexible ureteroscope combined with a tip-flexible suctioning ureteral access sheath for the treatment of kidney stones.

To compare the efficacy and safety of using a 7.5 Fr flexible ureteroscope (f-URS) with tip-flexible suctioning ureteral access sheath (TFS-UAS) versus a 9.2 Fr f-URS with traditional ureteral access sheath (T-UAS) in the treatment of kidney stones. A retrospective analysis was conducted on 205 patients with kidney stones measuring 1.0-2.0cm treated with 7.5 Fr and 9.2 Fr f-URS in the Urology Department of The Affiliated Dazu Hospital of Chongqing Medical University from November 2022 to November 2023. The patients were randomly divided into two groups. Among them, 78 patients were selected to use the 7.5 Fr f-URS, which was designated as the GroupA. The remaining 127 patients were selected to use the 9.2 Fr f-URS, which served as the GroupB. The study compared the operation duration, lithotripsy duration, surgical success rate, immediate postoperative stone-free rate (SFR), 1-month postoperative SFR, and the incidence rate of postoperative complications between the two patient groups. In terms of demographic characteristics, the size of calculi, surgical success rate, and 1-month postoperative SFR, there was no statistically significant difference between GroupA and GroupB. However, GroupA demonstrated superior performance compared to GroupB in operation duration (48 (40.55) min vs 74 (56.94) min), lithotripsy duration (35 (27.43) min vs 59 (42.78) min), and immediate postoperative SFR (53.52% (38/71) vs 29.41% (35/119)), with statistically significant differences observed (P < 0.05). In terms of complication occurrence, GroupA reported 10 cases of minor (Grade 1) complications, whereas GroupB had 32 cases of minor (Grade 1) complications and 7 cases of severe complications (including 2 cases of Grade 3 and 5 cases of Grade 4). The difference between the two groups was statistically significant (P < 0.05). The GroupA reported significantly fewer cases of postoperative fever (4) and analgesic treatment (3) compared to GroupB, which had 18 fever cases and 19 analgesic cases (P < 0.05).The GroupA did not experience any cases of septicemia or steinstrasse. Conversely, the GroupB had 5 cases of septicemia and 3 cases of steinstrasse, including 2 patients who underwent reoperation. Both groups also reported cases of ureteral mucosal rupture (5 in GroupA, 10 in GroupB), but these differences were not statistically significant (P > 0.05). Compared with 9.2 Fr f-URS combined with T-UAS, the use of 7.5 Fr f-URS with TFS-UAS in the treatment of kidney stones has higher lithotripsy efficiency and lower complication rate. This combination is safe and effective in the treatment of kidney stones.

Comparison of the safety of flexible ureteroscopy with the different irrigation methods in a 3D print kidney model.

To compare intrarenal pressure (IRP) and irrigation flow by varying suspended water heights and hand-held pressure pumping during flexible ureteroscopy using an in vitro 3D printed kidney model. A 3D-printed silicone model was used to simulate the kidney. The ureteral access sheath(UAS) was connected to the kidney model and positioned at the ureteropelvic junction. Central venous pressure tubing was used to monitor the pressure in the renal pelvis under different conditions. Sheath sizes of 12Fr and 14Fr were tested with flexible ureteroscope (fURS) sizes of 7.5, 8.5, and 9.5Fr, respectively. The irrigation was gravity-based, with suspended water heights set at 60, 90, 120, 150, and 180cm. The manual pumping as another set of measurement is used to measure the maximum intrarenal pressure. Using a 12Fr sheath with a 9.5Fr fURS loading without additional accessories resulted in IRP ranging from 8.4 to 17.5 cmH2O, while manual pumping perfusion pressure exceeded 60 cmH2O. Loading a 200-um laser fiber reduced the pressure to 6.4-10.5 cmH2O, and using a stone basket decreased it to 4.0-5.0 cmH2O. Using a 14Fr sheath with a 9.5Fr fURS resulted in an IRP of 2.5-6.0 cmH2O, compared to 17 cmH2O with manual pumping. With a 12Fr sheath and a 7.5Fr fURS, the IRP ranged from 5.4 to 8.2 cmH2O, while manual pumping resulted in 25.5 cmH2O. With a 14Fr sheath and a 7.5Fr fURS, the IRP ranged from 1.5 to 4.3 cmH2O, and manual pumping resulted in 9.0 cmH2O. When using a UAS in a flexible ureteroscopy, the IRP can be maintained within a safe range with different fURS/UAS combos with a suspended water height of less than 180cm. However, with specific fURS/UAS(9.5Fr/12Fr) combos, the IRP exceeded the safe limit when using manual pumping. Gravity irrigation with a suspended water height of less than 180cm is safe in this simulated clinical environment.

Efficacy analysis of tip-flexible suction access sheath during flexible ureteroscopic lithotripsy for unilateral upper urinary tract calculi.

This study aims to evaluate the efficacy of tip-flexible suctioning ureteral access sheath (TFS-UAS) compared to traditional ureteral access sheath (T-UAS) in flexible ureteroscopic lithotripsy (FURL) for unilateral upper urinary tract calculi. The study retrospectively compared outcomes from 103 cases using TFS-UAS and 138 using T-UAS treated with FURL for unilateral upper urinary tract calculi from January to October 2023. Assessed parameters included patient demographics, stone characteristics, preoperative urine cultures, ureteral pre-stenting, comorbidities, procedure time, stone-free rate (SFR), utilization of stone retrieval baskets, and postoperative Systemic Inflammatory Response Syndrome (SIRS) rates. The maximum angle of deflection was also measured when the flexible ureteroscope was located in different parts of the TFS-UAS with different diameters in vitro. The TFS-UAS group achieved a higher Immediate SFR (76.70% vs. 63.77%, p = 0.031) and final SFR (89.32% vs. 73.91%, p = 0.003) than the T-UAS group, especially in the lower calyx stones (80.00% vs. 41.18%, p = 0.018) and upper urinary tract calculi with a cumulative diameter of 2cm or larger (68.97% vs. 42.11%, p = 0.029). Notably, TFS-UAS with a 10 French (F) inside diameter size achieved a higher SFR (88.57% vs. 70.59%, p = 0.041) and a greater deflection angle than the 12.5F inside diameter size. No significant variations were observed in the operative duration, hospitalization duration and the occurrence of SIRS between the compared cohorts. TFS-UAS significantly improves SFR in FURL treatment of unilateral upper urinary tract calculi, particularly for stones located in the lower calyx or with a cumulative diameter of 2cm or greater, compared to T-UAS.

The infection post flexible UreteroreNoscopy (I-FUN) predictive model based on machine learning: a new clinical tool to assess the risk of sepsis post retrograde intrarenal surgery for kidney stone disease.

To create a machine-learning model for estimating the likelihood of post-retrograde intrarenal surgery (RIRS) sepsis. All consecutive patients with kidney stone(s) only undergoing RIRS in 16 centers were prospectively included (January 2022-August 2023). adult, renal stone(s) only, CT scan (within three months), mid-stream urine culture (within 10 days). concomitant ureteral stone, bilateral procedures. In case of symptomatic infection/asymptomatic bacteriuria, patients were given six days of antibiotics according to susceptibility profiles. All patients had antibiotics prophylaxis. Variables selected for the model: age, gender, age-adjusted Charlson Comorbidity Index, stone volume, indwelling preoperative bladder catheter, urine culture, single/multiple stones, indwelling preoperative stent/nephrostomy, ureteric access sheath, surgical time. Analysis was conducted using Python programming language, with Pandas library and machine learning models implemented using the Scikit-learn library. Machine learning algorithms tested: Decision Tree, Random Forest, Gradient Boosting. Overall performance was accurately estimated by K-Fold cross-validation with three folds. 1552 patients were included. There were 20 (1.3%) sepsis cases, 16 (1.0%) septic shock cases, and three more cases (0.2%) of sepsis-related deaths. Random Forest model showed the best performance (precision = 1.00; recall = 0.86; F1 score = 0.92; accuracy = 0.92). A web-based interface of the predictive model was built and is available at https://emabal.pythonanywhere.com/ CONCLUSIONS: Our model can predict post-RIRS sepsis with high accuracy and might facilitate patient selection for day-surgery procedures and identify patients at higher risk of sepsis who deserve extreme attention for prompt identification and treatment.

RIRS with FV-UAS vs. ESWL for the management of 1-2 cm lower pole renal calculi in obese patients: a prospective study.

To evaluate the efficacy and safety of retrograde intrarenal surgery (RIRS) combined with flexible vacuum-assisted ureteral access sheath (FV-UAS) versus extracorporeal shock wave lithotripsy (ESWL) for the management of 1-2 cm lower pole renal calculi (LPC) in obese patients. This prospective, randomized study included 149 obese patients with 1-2 cm LPC. Patients were allocated into two groups: 76 patients underwent RIRS with FV-UAS, and 73 patients received ESWL. The parameters assessed included stone-free rate (SFR), retreatment rate, complications, operative time, and pain intensity measured by the visual analog scale (VAS). Stone-free status was defined as the absence of stones on computed tomography or residual fragments smaller than 4 mm at 4 weeks post-procedure. The baseline characteristics of the two groups were comparable. The SFR was significantly higher in the RIRS group, reaching 86.8%, compared to 63.0% in the ESWL group (p = 0.034). Furthermore, the retreatment rate was significantly lower in the RIRS group, at 5.2%, versus 24.7% in the ESWL group (p < 0.001). The average operative time for RIRS was notably longer, at 65.3 ± 6.4 min, compared to 25.3 ± 7.8 min for ESWL (p < 0.001). The complication rates were 9.2% for the RIRS group and 6.8% for the ESWL group, with no statistically significant difference (p = 0.326). All complications were classified as Grade I or II according to the modified Clavien classification system. No significant differences were observed between the two groups regarding pain VAS scores and the composition of the stones. RIRS with FV-UAS demonstrated superior efficacy, evidenced by a higher SFR and reduced retreatment rates compared to ESWL, despite a longer operative duration. Both treatment modalities showed comparable safety profiles. RIRS with FV-UAS emerges as a viable, effective, and reproducible intervention for managing 1-2 cm LPC in obese patients, providing significant clinical advantages.

Optimal deflection techniques for flexible and navigablesuction ureteral access sheaths (FANS): a comparative in vitro PEARLS analysis.

Flexible and navigable suctionureteral access sheaths (FANS) have been introduced without current evidence on how to optimize deflection. Aim was to evaluate in vitro deflection angles with 2 different FANS techniques-sheath advancement and ureteroscope deflection; and effects of sheath size-ureteroscope combinations. We evaluated in vitro deflection angles of 10/12Fr, 11/13Fr and 12/14Fr FANS (Hunan Reborn Medical Co. Ltd) with six single-use flexible ureteroscopes (Pusen Uscope 7.5Fr, OTU WiScope 7.5Fr, OTU WiScope 8.6Fr, Innovex EU-scope 8.7Fr, Red Pine RP-U-C12 8.7Fr and Boston Scientific Lithovue 9.5Fr). Two deflection techniques were tested: (1) sheath advancement-advancing the sheath forward over a maximally deflected ureteroscope, and (2) ureteroscope deflection-maximally deflecting the ureteroscope from various starting positions relative to tip of the sheath. Intra and inter-scope comparisons of maximum deflection angles were significantly different (all ANOVA p < 0.01). Largest maximumangles for all ureteroscopes were with the sheath advancement technique (range 218°-277°), and second largest for most scopes using the ureteroscope deflection technique at tip (range 111°-212°), mostly deviating from manufacturer specifications (range 270°-275°). 10/12Fr and 11/13Fr sheath sizes were more flexible than 12/14Fr. Largest angles were with 11/13Fr sheath-OTU8.6Fr/Innovex8.7Fr combinations. Optimal deflection with FANS is achieved using either a sheath advancement technique, or ureteroscope deflection technique at tip. Despite using these optimized techniques, deflection angles specified by manufacturers seem hardly achievable. The sheath advancement technique and 11/13Fr sheath-OTU8.6Fr/Innovex8.7Fr combinations may be better suited for lower pole situations. Urologists should be aware of these differences and apply the findings to their FANS technique.

Clinical determination of the natural distensibility of the human ureter: initial study.

To define the natural distensibility of the human ureter and evaluate the impact of other possibly favourable factors on ureteric distensibility. A total of 101 patients undergoing ureteroscopic stone removal or percutaneous nephrolithotomy underwent ureteric sizing using sequential passage of 37-cm urethral dilators in 2-F increments while attached to a unique force sensor. Insertion forces were limited to 6 N. After 6 N was attained, an appropriately sized ureteric access sheath was passed. At the conclusion of each procedure, Post-Ureteroscopic Lesion Scale score was determined. Urethral dilators were passed in 61% of patients at ≤14 F; 39% of patients accepted urethral dilators of ≥16 F. The mean dilator size was 14 F. Multivariate logistic regression analysis revealed that preprocedural ureteric stenting and antibiotic use favoured passage of 16-F dilators (odds ratio [OR] 5.16, 95% confidence interval [CI] 1.70-15.62 [P = 0.004] and OR 5.15, 95% CI 1.743-15.243 [P = 0.003], respectively). Neither tamsulosin nor prior urinary tract infection had an impact on ureteric size (OR 0.765, 95% CI 0.281-2.084 [P = 0.601], OR 1.049, 95% CI 0.269-4.089 [P = 0.945], respectively). Using continuous insertion force monitoring and a 6-N threshold, the majority of unstented adult human ureters within our patient population safely accommodated a 14-F dilator. Safe passage of a 16-F dilator at the 6-N threshold was more likely among patients with a preexisting indwelling ureteric stent or patients who were treated with antibiotics within a week of the procedure.

Effect of preoperative Silodosin on facilitating access sheath placement in retrograde intrarenal surgery. A randomized controlled studys

ABSTRACT Introduction to evaluate the effect of preoperative Silodosin on ureteric dilatation to facilitate ureteral access sheath (UAS) placement and reduction of ureteral wall injury in retrograde intrarenal surgery (RIRS). Methods one hundred and twenty patients with renal or ureteric stones were randomly allocated into 2 equal groups. Group A represents patients who received a 7-day preoperative single dose Silodosin before RIRS while Group B represents patients who received a placebo for the same regimen. Our primary outcome was to assess the success rate of (UAS) placement. Our secondary outcomes were to evaluate the perioperative complication rate, stone-free rate, hospital stay, and cost analysis. Results In our study, Silodosin showed a higher success rate for (UAS) insertion compared to placebo with a statistically significant difference (p-value = 0.04). Spontaneous UAS insertion in the Silodosin group was 58.3%, which was increased with active ureteric dilatation to 98.3%. Preoperative Silodosin led to less postoperative pain and analgesics requirements without impacting postoperative hospital stay or stone-free rate. There was less ureteric injury incidence in the Silodosin group compared to placebo with a statistically significant difference (p-value = 0.002). Conclusion Preoperative Silodosin facilitates UAS insertion with a protective role against ureteric injury compared to placebo.

Intelligent control of pressure based on ureteral access sheaths: renal pelvic pressure during flexible ureteroscope perfusion at different sites.

This study aimed to evaluate the accuracy and effectiveness of renal pelvic pressure (RPP) control during flexible ureteroscopic perfusion at various sites. Flexible ureteroscopy for the intelligent control of RPP was based on a ureteral access sheath (UAS) that integrated pressure measurement and suction functions (with automatic adjustment). Eleven consecutive patients with indurating nephrostomy tubes were enrolled. The nephrostomy tube was connected to a disposable invasive blood pressure sensor. The RPP was zeroed after the pressure stabilized. The flow rate and control value were set at 100ml/min and - 5 mmHg, respectively. An 8.5 Fr flexible ureteroscope was irrigated at the renal pelvis, as well as the upper, middle, and lower calyces of the kidney for 1min. All 11 patients with upper urinary tract calculi underwent successful UAS placement. Pressures measured by the sheath and fistula during perfusion were - 5.07 ± 1.41 and - 4.89 ± 1.07 mmHg at the renal pelvis, -5.16 ± 1.36 and - 5.12 ± 1.32 mmHg at the upper calyces, -4.98 ± 0.87 and - 5.39 ± 1.01 mmHg at the middle calyces, as well as -4.95 ± 1.56 and - 5.64 ± 1.24 mmHg at the lower calyces, respectively. There were no significant differences in pressure between the sheath and fistula groups or in sheath and fistula pressures among parts. The RPP fluctuated; however, all values were within the safe limit of 20 mmHg. The UAS-based pressure monitoring technology can accurately and reliably monitor and control RPP within a set range.

Development and validation of a predictive model for failure of ureteral access sheath placement in patients with ureteral calculi

ObjectiveThe Ureteral Access Sheath (UAS) has notable benefits but may fail to traverse the ureter in some cases. Our objective was to develop and validate a dynamic online nomogram for patients with ureteral stones who experienced UAS placement failure during retrograde intrarenal surgery (RIRS).MethodsThis study is a retrospective cohort analysis using medical records from the Second Hospital of Tianjin Medical University. We reviewed the records of patients with ureteral stones who underwent RIRS in 2022 to identify risk factors associated with UAS placement failure. Lasso combined logistic regression was utilized to identify independent risk factors associated with unsuccessful UAS placement in individuals with ureteral stones. Subsequently, a nomogram model was developed to predict the likelihood of failed UAS placement in this patient cohort. The model’s performance was assessed through Receiver Operating Characteristic Curve (ROC) analysis, calibration curve assessment, and Decision Curve Analysis (DCA).ResultsSignificant independent risk factors for unsuccessful UAS placement in patients with ureteral stones included age (OR = 0.95, P < 0.001), male gender (OR = 2.15, P = 0.017), body mass index (BMI) (OR = 1.12, P < 0.001), history of stone evacuation (OR = 0.35, P = 0.014), and ureteral stone diameter (OR = 0.23, P < 0.001). A nomogram was constructed based on these variables. Model validation demonstrated an area under the ROC curve of 0.789, indicating good discrimination. The calibration curve exhibited strong agreement, and the decision curve analysis revealed a favorable net clinical benefit for the model.ConclusionsYoung age, male sex, high BMI, no history of stone evacuation, and small diameter of ureteral stones were independent risk factors for failure of UAS placement in patients with ureteral stones, and the dynamic nomogram established with these 5 factors was clinically effective in predicting the outcome of UAS placement.

First clinical evaluation of a flexible digital ureteroscope with direct in scope suctioning system (Pusen DISS 7.5Ch): prospective multicentric feasibility study.

A new digital single-use flexible ureteroscope, Pusen direct in scope suction (DISS) 7.5Fr (PU3033AH), was evaluated with respect to manoeuvrability, suction quality, visibility and clinical efficiency. A prospective cohort study was conducted in six tertiary reference centers in Europe and Asia between February-April 2024. Adult patients who underwent flexible ureteroscopy and laser lithotripsy (fURSL) for urolithiasis were included. Demographic, intraoperative and follow-up characteristics were recorded. Quality parameters were rated by each surgeon using a Likert scale. a total of 57 fURSL were performed. Preoperative characteristics revealed a mean stone volume of 480.00mm3 (mean Hounsfield Unit- 998). 57.9%(n = 33) of the patients were pre-stented, and a ureteric access sheath was used in 64.9%(n = 37). Integrated-suction was deemed helpful in 94.7%(n = 54) fURSL as reported by the operators. An initial stone free rate (SFR) confirmed by postoperative imaging was achieved in 84.21%(n = 48). Quality parameters of the scope reached a mean Likert score of 4.5, with a "very good" mean evaluation for "scope placement", "visual quality", "irrigation", "deflection", "manoeuvrability", and "weight". "Suction quality" and "overall performance satisfaction" were rated "good". Comparing the Pusen DISS scope with other previously used scopes, overall satisfaction was rated 4.1. When asked if the surgeons would be willing to use the Pusen DISS 7.5Fr scope in the future, all the six surgeons answered positively. The DISS 7.5 Pusen ureteroscope displayed good visibility, manoeuvrability and suction quality, with excellent operative results. Further evaluation with larger comparative cohorts will help understand the potential of in-vivo use of integrated suctioning systems for fURSL.

Ureteral access sheaths in RIRS: a retrospective, comparative, single-center study.

To evaluate the use of ureteral access sheaths (UAS) in reducing operative time and complications, as well as improving stone-free rates (SFR), while assessing their overall safety and efficiency. Data regarding 234 patients who underwent retrograde intrarenal surgery (RIRS) for stones up to 3 cm between January 2017 and March 2020 were retrospectively analyzed. About 52.5 % of procedures were performed utilizing a UAS. Differences in operative time, fluoroscopy time, stone-free rate, and complications were analyzed between procedures with and without UAS and stratified, according to stone burden size, into three groups (Group A: 0.5-1 cm; Group B: 1-2 cm; Group C: 2-3 cm). Operative time, fluoroscopy time, and residual fragments size were lower in RIRS without UAS, respectively, 54.27±24.02 vs. 62.23±22.66 min (p=0.010), 2.72±0.89 vs. 4.44±1.67 min (p<0.0001), and 3.85±0.813 vs. 4.60±0.83 mm (p=0.011). Considering stone burden, operative time was lower in RIRS without UAS for Group A (36.40±8.555 vs. 46.05±6.332 min) (p<0.0001) while higher for Group B (60.39±18.785 vs. 50.14±5.812 min) (p=0.002). Similarly, fluoroscopy time was lower in RIRS without UAS in every group, respectively, 2.11±0.34 vs. 2.74±0.57 min (p<0.0001), 2.94±0.51 vs. 4.72±0.37 min (p<0.0001), and 3.78±1.26 vs. 6.79±1.17 min (p<0.0001). Only Group C had a statistically significant difference in residual fragment size without UAS(3.89±0.782 vs. 4.75±0.886 mm) (p=0.050). UAS should be carefully evaluated considering the increased fluoroscopy time and the differences in operative time related to different stone burdens.

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.

The efficacy of flexible ureteroscopy for large volume stones and hazards of ureteral access sheath usage: A prospective randomized study

ABSTRACT Objectives We aimed to assess the stone free rate of flexible ureteroscopy and laser lithotripsy (FURL) in upper urinary tract stones (UUTS) >20 mm and the risk of complications from ureteral access sheath (UAS) usage. Methods This is a prospective randomized clinical trial that included patients with UUTS larger than 20 mm who underwent FURL after randomization into two groups: group A (UAS) and group B (non-UAS). Data were collected for patients’ demographics, stone parameters, operative and postoperative complications, and the outcome of FURL regarding stone-free rate (SFR) and perioperative complications, with a 6-month follow-up. Stone clearance was defined as the absence of fragments or the presence of fragments smaller than 2 mm on follow-up CT scans of the urinary tract (CTUT). Results One hundred and fifty-nine patients were evaluated. The mean stone size was 27.08 ± 6.185 mm. Complete stone-free status was achieved in 84.9% of the patients. No significant difference was detected between both groups regarding operative time or SFR. The ureteric injury was identified in 13 (8.1%) patients (10 in group A and 3 in group B, p: 0.0481). Five of them, from group A, revealed hydronephrosis after stent removal. Postoperative pain and fever were documented in 50 and 22 patients, respectively, without significant differences between both groups. Postoperative sepsis occurred in 7 patients (2 in group A, 5 in group B, p: 0.380) who required supportive care. Conclusion FURL without UAS is a safe and efficient treatment for upper urinary tract stones larger than 20 mm in the form of lower risk of ureteric injury.

Operative outcomes 24 hours after retrograde intrarenal surgery for solitary renal calculi using a flexible and navigable suction ureteral access sheath. A prospective global multicenter study by the European Association of Urology Section on Urolithiasis.

Suction techniques showed potential to improve outcomes of retrograde intra-renal surgery (RIRS). We assessed the 24-hour stone-free rate (SFR) and complications after RIRS using flexible and navigable suction ureteral access sheaths (FANS-UAS). Sixteen centers prospectively contributed to data (August 2023-October 2023). Inclusion criteria: age ≥18 years, single renal stone, pre and 24-hour post-RIRS CT scan. Exclusion criteria were: ureteral stone, anomalous kidney, multiple stones. SFR was divided into: 1) grade A - no fragments; 2) grade B - fragments ≤2 mm; 3) grade C - fragments 2.1-4 mm; and 4) grade D - fragments >4 mm. A multivariable logistic regression analysis model was performed to assess factors associated with the odds of having grade A stone-free status. Data are expressed as median (interquartile range), absolute numbers and frequencies, odds ratio (OR), and 95% confidence interval (CI). One hundred forty-two patients with a median age of 52 years (40-61) were enrolled. 61.3% were males. Median stone volume was 1165 mm3 (656-1936). Median operative time was 48.5 (36.25-71.75) min. Transient fever (37°C-37.5°C) occurred in 10 (7%) patients. No sepsis case occurred. 96.5% of patients were stone-free (Grade A+B). Grade A SFR was 52.8%. All patients were discharged within 48 hours. Bone window (OR 3.156 95% CI 1.177-9.130, P=0.027) was the only factor significantly associated with higher odds of 100% SFR, while stone volume (OR 0.999, 95% CI 0.999-1.000, P=0.007) was significantly associated with lower odds. Imaging and clinical evidence demonstrate excellent perioperative outcomes just 24 hours post RIRS with FANS-UAS. The technique demonstrates a good safety profile, ability for immediate high SFR, and a low rate of infective complications.

Outcomes of Ureteroscopy and Laser Lithotripsy With and Without Ureteral Access Sheaths for the Treatment of Renal Calculi: A Systematic Review and Meta-analysis

Outcomes of Ureteroscopy and Laser Lithotripsy With and Without Ureteral Access Sheaths for the Treatment of Renal Calculi: A Systematic Review and Meta-analysis

The impact of preoperative ureteral stent duration on retrograde intrarenal surgery results: a RIRSearch group study.

A JJ stent placed before retrograde intrarenal surgery (RIRS) may ease the procedure. However, it is important to note that a prolonged duration of double J stent (DJS) placement before RIRS may increase the risk of postoperative urinary tract infection (UTI). Various publications have established this association, although the duration of the DJS before surgery is scarce. Our study investigates the relationship between the pre-stenting period and postoperative UTI and establishes a cut-off period to minimize this risk. We included a total of 500 cases with preoperative DJS prior to RIRS. The patients were divided into five groups according to their preoperative stenting duration (Group 1: 0-15 days; Group 2: 16-30 days; Group 3: 31-45 days; Group 4: 46-60 days; Group 5: >60 days). Demographic and clinical data of the patients, stone properties, operation data, perioperative and postoperative complications (including fever and UTI), hospitalization time, and stone-free rates (SFR) were compared. The groups contained 53, 124, 102, 63, and 158 patients. The demographics of the patients in each group were similar. There was no statistically significant difference between DJS duration, perioperative/postoperative complications, and SFR, except for the ureteral access sheath (UAS) insertion rate. (p = 0.001). The postoperative fever/UTI rate was the lowest in Group 1 (p = 0.046) compared to other durations. Stent duration does not impact SFR. Longer stents enhance UAS insertion success but increase postoperative infection risk. Our results suggest that RIRS should be performed within two weeks, ideally 20 days following stent insertion, to minimize postoperative infection risk.

The Evaluation of Intrarenal Pressure Using a Novel Single-Use Flexible Ureteroscope with Live Intrarenal Pressure Monitoring-An Experimental Study in Porcine Models.

(1) Background: This study aims to evaluate how different irrigation settings and the use of ureteral access sheaths (UASs) of varying sizes impact intrarenal pressure (IRP) during flexible ureteroscopy (fURS) procedures in pigs. (2) Methods: This study utilized three anesthetized female pigs. A novel flexible ureteroscope with the ability to continuously record live intrarenal pressure was used to perform ureteroscopy in different settings. Ureteroscopy was performed without UAS and with the use of 11/13 and 12/14 UAS at the ureteropelvic junction. Two different irrigation methods were employed for each parameter: one using gravity flow and the other using manual pumping with a commercial pump. IRP was also recorded with the presence of a laser fiber or lithotripsy basket. (3) Results: The recorded mean IRP during flexible URS without UAS was 28.25 (±11.2) under gravity irrigation; 35.46 (±10.08) under manual pumping; 22.5 (±3.05) and 30.75 (±5.79) with a laser fiber under gravity irrigation and manual pumping, respectively; and 16.45 (±1.27) and 17.27 (±3.69) with a lithotripsy basket under gravity irrigation and manual pumping, respectively. With an 11/13 UAS, the mean IRP was 15.41 (±8.57) and 19.33 (±4.26) under gravity and manual pumping irrigation, respectively; 14.56 (±2.50) and 18.64 (±5.13) with a laser in each irrigation setting, respectively; and 13.10 (±3.39) and 13.86 (±4.63) with a lithotripsy basket, respectively. With a 12/14 UAS, the mean IRP was 7.64 (±3.08) and 9.25 (±1.42) under gravity and manual pumping irrigation, respectively; 9.50 (±6.04) and 10.28 (3.46), respectively, in each setting when the laser fiber was used; and 5.32 (±1.57) and 6.26 (±1.79), respectively, when the lithotripsy basket was inserted. (4) Conclusion: Novel flexible ureteroscopes with integrated pressure sensors are both a feasible and reliable tool during fURS, giving the surgeon the ability to live-track the IRP. The results of the IRP measurements with and without UAS are in accordance with the current literature and exhibit a consistent pattern with previous studies.

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

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