Comparative Study of Ureteral Access Sheath versus Suction Access Sheath in Retrograde Intrarenal Surgery

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Huang, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6739619/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 19 Dec, 2025 Read the published version in BMC Urology → Version 1 posted 10 You are reading this latest preprint version Abstract Introduction: Retrograde intrarenal surgery (RIRS) is a minimally invasive technique for managing renal and upper ureteral stones. Ureteral access sheaths (UAS) facilitate instrument access and reduce intrarenal pressure, but their impact on stone-free rates (SFR) remains debated. Suction ureteral access sheaths (S-UAS) offer improved flexibility and can be connected to suction devices, enhancing stone fragment removal. This study aims to compare the outcomes of traditional UAS and S-UAS in RIRS. Methods A retrospective cohort study was conducted at Chimei Medical Center from January 2022 to December 2024, including 104 patients who underwent RIRS with either traditional UAS (n = 53) or S-UAS (n = 51). Baseline characteristics, operative time, stone-free rates (SFR), postoperative complications, and the need for auxiliary procedures were analyzed. Subgroup analyses assessed the impact of stone size, location, and number on outcomes. Results Immediate SFR was significantly higher in the S-UAS group (82.0%) compared to the traditional UAS group (60.4%) (p = 0.016). At one month, no significant difference was observed between the groups. The S-UAS group required fewer auxiliary procedures (5.9% vs. 22.6%, p = 0.015) and demonstrated a higher SFR for lower calyx stones (81.8% vs. 55.2%, p = 0.046). Operative time, hospital stay, and complication rates were similar between groups. The incidence of postoperative sepsis was higher in the S-UAS group, though other complications remained comparable. Discussion The S-UAS significantly improved immediate SFR in RIRS, particularly for larger stones, single stones, and lower calyx stones. While postoperative sepsis was more common in the S-UAS group, the overall complication rates were low. The suction capability of the S-UAS enhances stone clearance and reduces the need for additional interventions. Conclusion The S-UAS offers significant benefits over traditional UAS in improving immediate SFR, particularly in challenging stone cases. Despite a higher rate of postoperative sepsis, S-UAS appears to be a safe and effective option for RIRS, reducing the need for auxiliary procedures and enhancing procedural efficiency. Further studies are needed to evaluate long-term outcomes and refine patient selection for optimal results. Clinical trial number: not applicable. Retrograde Intrarenal Surgery (RIRS) Suction Ureteral Access Sheath (S-UAS) Traditional Ureteral Access Sheath (UAS) Stone-Free Rate (SFR) Introduction Retrograde intrarenal surgery (RIRS) has become a cornerstone in the management of renal and upper ureteral stones, offering a minimally invasive alternative to percutaneous nephrolithotomy (PCNL). According to the European Association of Urology (EAU) guidelines, RIRS is recommended for kidney stones 10 mm( 1 ). A critical component of successful RIRS is the use of ureteral access sheaths (UAS), which facilitate repeated instrument access, reduce intrarenal pressure, and enhance irrigation flow during surgery( 2 ). However, studies have shown that the use of a UAS does not significantly improve stone-free rates (SFR) or operative duration( 2 ). The limitations of traditional UAS, particularly in effectively clearing stone fragments, have driven the development of innovative solutions, such as the suction ureteral access sheath (S-UAS). The S-UAS is distinguished by its excellent flexibility and deformability at the tip, allowing it to passively bend in alignment with the flexible ureteroscope. Furthermore, the S-UAS can be connected to a vacuum suction device, enabling efficient removal of residual stone fragments while further reducing intrarenal pressure. This design has the potential to SFR and minimize complications associated with retrograde intrarenal surgery. Studies have demonstrated the superior performance of S-UAS compared to traditional UAS, with Zhu et al. reporting significantly higher SFRs (81.3% versus 49.4%)( 3 ), and Wang et al. showing similar improvements (88.73% versus 75.68%), along with a reduction in postoperative fever rates( 4 ). Despite its theoretical advantages, the benefits of the S-UAS in addressing variations in stone size, location, and complexity have been rarely explored. This study aims to share our experience in managing upper tract stones by retrospectively comparing the outcomes of traditional UAS and S-UAS in RIRS. Key outcomes assessed include immediate and delayed SFRs, operative time, postoperative complications, and the necessity for auxiliary procedures. By performing detailed subgroup analyses, this study seeks to provide a comprehensive evaluation of the clinical utility of S-UAS. Methods This retrospective cohort study was conducted at Chimei Medical Center between January 2022 and December 2024. It aimed to compare the efficacy and safety of traditional ureteral access sheath (UAS) and suction ureteral access sheath (S-UAS) in retrograde intrarenal surgery (RIRS). Patients were identified from electronic medical records and included if they met the following criteria: adults aged 18 years or older with renal or upper ureteral stones, confirmed by non-contrast computed tomography (CT) imaging, with stone diameters ≤30 mm. Patients with abnormal urinary tract anatomy (e.g., horseshoe kidney), active urinary tract infections, contraindications for RIRS, or those undergoing concurrent surgical procedures such as percutaneous nephrolithotomy (PCNL) were excluded. Additionally, cases with incomplete data or failure to complete the assigned procedure were excluded. A total of 121 patients were initially identified, but after exclusions for reasons such as anatomical challenges or procedural changes, 104 patients were included in the final analysis. These were divided into the traditional UAS group (n=53) and the S-UAS group (n=51). Baseline demographic and clinical data, including age, gender, body mass index (BMI), stone characteristics (location, size, and density), and preoperative laboratory values, were collected. All surgeries were performed by experienced urologists using standardized protocols under general anesthesia. Preoperative imaging consisted of 2-mm non-contrast CT scans to assess stone size and density. Stone size was defined by both the maximum diameter of the largest stone and the cumulative sum of all stone diameters. Stone density was measured in Hounsfield units (HU). Traditional UAS cases predominantly employed manual irrigation with a 50 cc syringe and nitinol stone baskets for fragment retrieval. In contrast, the S-UAS group used a suction-assisted sheath with adjustable suction pressures (50–100 mmHg) to facilitate stone aspiration during fragmentation. Flexible ureteroscopes of varying sizes (7.5–9.5 F) were utilized according to sheath dimensions. Holmium laser lithotripsy was employed with settings adjusted for dusting, fragmentation, or popcorn modes, depending on stone size and composition. Postoperative double-J stents were routinely placed and removed 1–2 weeks after surgery. Immediate stone-free status was assessed via endoscopy and imaging (kidney-ureter-bladder X-ray [KUB] and ultrasound) within 24 hours, while follow-up imaging at one month further evaluated residual stone fragments. The primary outcomes were immediate stone-free rates (SFRs) defined as the absence of stone fragments >4 mm and >2 mm. Secondary outcomes included SFRs at one month, operative time (defined from ureteroscope insertion to stent placement), hospital stay duration, auxiliary procedures, and complications. Statistical analyses were performed using SPSS version 25.0. Continuous variables were compared using independent t-tests or Mann-Whitney U-tests as appropriate, while categorical variables were analyzed using Chi-square or Fisher’s exact tests. Subgroup analyses explored outcomes based on stone size, location, and type. Results Baseline demographic and clinical characteristics, including age, gender distribution, BMI, comorbidities, American Society of Anesthesiologists (ASA) classification, stone laterality, stone type, stone location, and stone size, were comparable between the two groups, with no statistically significant differences observed. The mean stone diameter was 14.27 ± 6.96 mm in the traditional UAS group and 13.74 ± 6.53 mm in the S-UAS group (p = 0.689). The preoperative serum creatinine levels and initial positive urine culture rates were also similar between groups. (Table 1) 3.1 Primary Outcomes The immediate stone-free rate (SFR), defined as the absence of residual stones >4 mm on postoperative imaging, was significantly higher in the S-UAS group (82.0%) compared to the traditional UAS group (60.4%) (p = 0.016). When considering a stricter threshold of 2 mm for SFR assessment, the S-UAS group still demonstrated superior clearance (70.0% vs. 50.9%, p = 0.048). At one month postoperatively, SFR at the 4 mm threshold remained higher in the S-UAS group (85.7% vs. 75.5%), but this difference did not reach statistical significance (p = 0.193). Similarly, the one-month SFR at the 2 mm threshold was comparable between groups (73.5% vs. 67.9%, p = 0.539). (Table 2) 3.2 Secondary Outcomes Operative time did not differ significantly between the two groups, with a mean duration of 95.9 ± 49.8 minutes in the S-UAS group and 98.4 ± 40.85 minutes in the traditional UAS group (p = 0.781). Postoperative hospital stay was also comparable, with a mean duration of 3.0 ± 3.69 days in the S-UAS group and 2.79 ± 2.32 days in the traditional UAS group (p = 0.733). Notably, the need for auxiliary procedures, such as extracorporeal shockwave lithotripsy (ESWL) or secondary endoscopic procedures, was significantly lower in the S-UAS group (5.9%) compared to the traditional UAS group (22.6%, p = 0.015). Regarding safety outcomes, the overall complication rates were low in both groups, with no statistically significant differences. Urosepsis was observed in 2.0% of patients in the S-UAS group and 3.8% in the traditional UAS group. Mucosal tear occurred in 3.8% of patients in the traditional UAS group, whereas no cases were reported in the S-UAS group. Bleeding complications were minimal, with a single case (1.9%) reported in the traditional UAS group and none in the S-UAS group. One case of ureteral stricture was noted in the S-UAS group. Postoperative renal function was assessed through serum creatinine measurements on postoperative day 1 and at three months. No significant differences were observed between the groups, suggesting that the use of S-UAS did not negatively impact renal function recovery. (Table 2) 3.3 Subgroup Analysis A subgroup analysis was performed to evaluate the efficacy of S-UAS in different stone sizes, stone locations, and stone burden. 3.3.1 Stone Size (Cutoff at 15 mm) For patients with large stones (>15 mm), the immediate SFR was significantly higher in the S-UAS group (81.3%) compared to the traditional UAS group (40.0%) (p = 0.018). This trend was not observed in patients with stones ≤15 mm, where SFR differences between the two groups were not statistically significant. (Supplement Table S1) 3.3.2 Stone Size (Cutoff at 20 mm) Patients were stratified based on sum of stone size, with a cutoff value of 20 mm to assess whether S-UAS is particularly beneficial for larger stone burdens. In patients with stones >20 mm, the immediate SFR was significantly higher in the S-UAS group compared to the traditional UAS group. In contrast, for patients with stones ≤20 mm, SFR was not significantly different between the two groups. (Supplement Table S2) 3.3.3 Stone Number When analyzing the impact of stone number, the S-UAS group showed significantly better outcomes in patients with single stones, achieving a 100% immediate SFR compared to 66.7% in the traditional UAS group (p = 0.008). However, in cases of multiple stones, SFR was higher in the S-UAS group (71.9%) compared to the traditional UAS group (57.9%), but the difference was not statistically significant (p = 0.224). (Supplement Table S3) 3.3.4 Stone Location The S-UAS group demonstrated a significant advantage in clearing lower calyx stones, with an immediate SFR of 81.8% compared to 55.2% in the traditional UAS group (p = 0.046). For stones located in other areas, including the renal pelvis, upper/middle calyx, upper ureter, or staghorn/multiple locations, no significant differences in SFR were found between the groups. (Supplement Table S4) 3.3.5 Postoperative White Blood Cell (WBC) Counts To further explore the postoperative inflammatory response, we compared preoperative and postoperative WBC counts. While preoperative WBC levels were slightly lower in the S-UAS group, postoperative WBC changes were not significantly different between groups, suggesting that S-UAS did not result in a markedly different inflammatory or infectious response compared to traditional UAS. Discussion This study highlights the real-world clinical relevance of the S-UAS in enhancing immediate stone clearance during RIRS compared to traditional UAS. Our retrospective analysis of 104 patients demonstrated a significantly higher immediate stone-free rate in the S-UAS group while maintaining comparable complication rates. Additionally, the need for auxiliary procedures was significantly lower in the S-UAS group, indicating improved procedural efficiency. Notably, our subgroup analysis revealed that S-UAS was particularly effective in managing large stones, single stones, and lower calyx stones, providing valuable guidance for optimizing clinical decision-making and surgical approaches. The implementation of S-UAS in RIRS has demonstrated increased efficacy, primarily through mechanisms such as the removal of debris, which enhances intraoperative visibility by mitigating the "snow-globe effect" and facilitating the identification of concealed fragments. This improvement in visualization contributes to higher immediate SFRs( 4 ). Previous studies have reported increased SFRs both immediately and at three months postoperatively, typically defining SFR as residual fragments smaller than 4 mm on KUB imaging, with the overall SFR ranged higher from 87.5% upwards( 5 , 6 , 7 , 8 ). In our study, we adopted a more stringent criterion by defining SFR as the absence of residual fragments larger than 2 mm on KUB imaging. This approach revealed a significant improvement in immediate SFR with the use of S-UAS. However, this significance did not persist at the one-month follow-up. This observation may be attributed to the natural clearance of small residual fragments through urination in patients treated with traditional UAS, thereby diminishing the immediate advantage observed with S-UAS. The aspiration capability of S-UAS not only enhances immediate stone clearance but also reduces the incidence of steinstrasse and the necessity for auxiliary procedures such as ESWL or secondary ureteroscopy. This reduction in additional interventions potentially contributes to a smoother postoperative recovery and an improvement in patients' quality of life( 3 , 4 ). Moreover, the effective aspiration of debris by S-UAS minimizes the need for fragment extraction using stone baskets, thereby streamlining the procedure. While other studies have reported a decrease in operative time with the use of S-UAS( 8 , 9 ), our findings did not demonstrate a significant reduction in surgery duration. This discrepancy may result from the additional time required to maneuver the suctional tip into the lower calyx. With increased experience and proficiency at our center, it is anticipated that this aspect of the procedure may become more efficient, potentially leading to shorter operative times in future studies. Advancements in RIRS technology have led to an increasing preference for endoscopic management of larger renal calculi. A feasibility study evaluating a novel tip-flexible suction ureteral access sheath (NTFS-UAS) in combination with flexible ureteroscopic lithotripsy for kidney stones ≥ 30 mm demonstrated promising outcomes, reporting immediate and 1-month SFRs of 83.98% and 85.44%, respectively. Multivariate analysis identified stone size (≥ 50 mm), multiple stones, and severe hydronephrosis as independent risk factors negatively affecting stone clearance rates.( 10 ) Our subgroup analysis further supports these findings, indicating that patients with a single stone larger than 15 mm or a cumulative stone diameter exceeding 20 mm achieved significantly better SFRs with the use of S-UAS. Moreover, improved SFR was observed for single stones, consistent with previous research. This suggests that S-UAS may be particularly beneficial in patients with a substantial stone burden, thereby expanding the applicability of RIRS for managing larger renal stones. Furthermore, Chen et al. compared suctioning semirigid ureteroscopic lithotomy (Sotn-URSL) with minimally invasive percutaneous nephrolithotomy (mPCNL) and reported an SFR of 84.6% in the Sotn-URSL group versus 92.3% in the mPCNL group, with the difference not reaching statistical significance (P = 0.34). Additionally, the Sotn-URSL group experienced shorter hospital stays and fewer complications compared to the mPCNL group.( 11 ) Based on these findings, S-UAS could be considered a viable alternative to mPCNL for patients with single renal stones measuring 20–50 mm, offering a less invasive option with comparable stone clearance outcomes. RIRS presents significant challenges in the management of lower calyceal stones due to the acute infundibulopelvic angle, which limits access and increases the need for frequent stone basket manipulation. These factors can complicate stone retrieval and prolong operative time, potentially impacting surgical efficiency and outcomes.( 12 , 13 ) In our study, the use of S-UAS resulted in a significantly higher SFR for lower calyx stones compared to traditional UAS. The incorporation of a bendable tip in S-UAS facilitates precise navigation into the targeted calyx, overcoming anatomical challenges associated with the lower pole. Additionally, the continuous suction mechanism enhances fragment evacuation, reducing residual stone burden and improving immediate clearance. Notably, prior studies evaluating tip-bendable UAS without suction have reported lower SFRs and increased reliance on stone baskets in the lower calyx subgroup.( 14 ) This suggests that while tip flexibility enhances maneuverability, the suction mechanism provides an additional advantage in fragment clearance. The application of S-UAS during RIRS offers significant advantages in managing intrarenal pressure (IRP) and enhancing irrigation flow. Effective regulation of IRP is crucial, as elevated pressures can lead to pyelovenous backflow, increasing the risk of mucosal injury within the collecting system and facilitating the reabsorption of irrigation fluid containing bacteria and endotoxins, potentially resulting in postoperative infectious complications such as sepsis.( 15 , 16 ) In our study, the use of S-UAS was associated with comparable overall complication rates to traditional UAS, with a lower incidence of postoperative urosepsis observed in the S-UAS group. Specifically, one patient in the S-UAS group developed urinary retention and fever following Foley catheter removal, which was later diagnosed as underactive bladder. In contrast, two patients in the traditional UAS group developed postoperative urinary tract infections. Notably, our study found no significant elevation in postoperative WBC counts in the S-UAS group compared to the traditional UAS group, indicating that the rate of sepsis was controlled and aligned with previous studies. This aligns with findings from other studies, such as one that demonstrated the application of suctioning UAS during flexible ureteroscopy was associated with lower incidence of postoperative fever or systemic inflammatory response syndrome (SIRS). ( 17 ) These observations underscore the importance of patient selection and preoperative optimization to mitigate the risk of infectious complications. Further studies are warranted to monitor IRP during S-UAS use and to establish protocols that ensure patient safety and optimal outcomes. This study has several limitations due to its retrospective design. The small sample size limits generalizability, especially for complex subgroups, such as those with multiple stones or high stone burden. The lack of randomization introduces potential selection bias, as clinical decisions may have influenced the choice of UAS. Additionally, the absence of long-term follow-up restricts evaluation of delayed complications or the natural passage of small residual stones, which could impact the long-term effectiveness of S-UAS. The study also lacked intrarenal pressure monitoring, which could have provided insights into the role of S-UAS in managing intrarenal pressure and preventing complications like sepsis. Lastly, while postoperative complications were assessed, renal functional outcomes, such as glomerular filtration rate (GFR), were not evaluated, which would be crucial for assessing long-term renal implications. Future research should employ a prospective, randomized controlled design with a larger cohort to validate these findings and reduce biases. Additionally, studies focusing on intrarenal pressure monitoring during RIRS with S-UAS could provide valuable insights into its safety profile and ability to prevent adverse events such as pyelovenous backflow and sepsis. Conclusion In conclusion, this study demonstrates that the S-UAS significantly improves immediate SFR during RIRS compared to the traditional UAS. The use of S-UAS was particularly beneficial for larger stones, single stones, and lower calyx stones, contributing to enhanced procedural efficiency and reduced need for auxiliary procedures. Although the S-UAS group showed a higher incidence of postoperative sepsis, complication rates were otherwise similar between groups. While no significant difference in operative time or hospital stay was observed, the improved SFR and reduced need for additional procedures suggest that S-UAS can optimize outcomes in RIRS, especially for challenging stone burdens. Further prospective studies with larger cohorts are needed to confirm these findings and explore the long-term benefits and safety of S-UAS. Abbreviations RIRS Retrograde Intrarenal Surgery UAS Ureteral Access Sheath S-UAS Suction Ureteral Access Sheath SFR Stone-Free Rate PCNL Percutaneous Nephrolithotomy CT Computed Tomography HU Hounsfield Unit WBC White Blood Cell IRP Intrarenal Pressure ASA American Society of Anesthesiologists KUB Kidney, Ureter, and Bladder radiograph URSSM Ureterorenoscopic Stone Surgery Manipulation Declarations Conflict of Interest Statement The authors certify that they have NO affiliations with or involvement in any organization or entity with any financial interest, or non-financial interest in the subject matter or materials discussed in this manuscript. Ethics approval and consent to participate This study was approved by the Institutional Review Board of Chi Mei Medical Center (IRB No. T34763). The requirement for informed consent was waived due to the retrospective nature of the study. All procedures were conducted in accordance with the ethical standards of the institutional and national research committee and with the 2013 Declaration of Helsinki. Consent for publication Not applicable. Funding This research received no external funding. Author Contribution TYC designed the study, collected and analyzed the data, and drafted the manuscript. KHL supervised the methodology and critically revised the manuscript. CCH, ZHC, SKH, and AWC contributed to data interpretation, figure generation, and manuscript refinement. All authors read and approved the final manuscript. Acknowledgements The authors would like to thank the nursing and administrative staff of the Urology Department at Chi Mei Medical Center for their assistance in patient care and data collection. The authors also appreciate the statistical guidance provided by the hospital’s Biostatistics Core Facility. Availability of data and materials The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. References Türk C, Petřík A, Sarica K, Seitz C, Skolarikos A, Straub M, et al. EAU Guidelines on Interventional Treatment for Urolithiasis. Eur Urol. 2016;69(3):475–82. Zeng G, Traxer O, Zhong W, Osther P, Pearle MS, Preminger GM, et al. International Alliance of Urolithiasis guideline on retrograde intrarenal surgery. BJU Int. 2023;131(2):153–64. Zhu W, Liu S, Cao J, Wang H, Liang H, Jiang K, et al. Tip bendable suction ureteral access sheath versus traditional sheath in retrograde intrarenal stone surgery: an international multicentre, randomized, parallel group, superiority study. EClinicalMedicine. 2024;74:102724. Wang L, Zhou Z, Gao P, Yang Y, Ding Q, Wu Z. Comparison of traditional and suctioning ureteral access sheath during retrograde intrarenal surgery in the treatment of renal calculi. Langenbecks Arch Surg. 2024;409(1):81. Yuen SKK, Traxer O, Wroclawski ML, Gadzhiev N, Chai CA, Lim EJ et al. Scoping Review of Experimental and Clinical Evidence and Its Influence on Development of the Suction Ureteral Access Sheath. Diagnostics (Basel). 2024;14(10). Gauhar V, Traxer O, Castellani D, Sietz C, Chew BH, Fong KY, et al. Could Use of a Flexible and Navigable Suction Ureteral Access Sheath Be a Potential Game-changer in Retrograde Intrarenal Surgery? Outcomes at 30 Days from a Large, Prospective, Multicenter, Real-world Study by the European Association of Urology Urolithiasis Section. Eur Urol Focus. 2024;10(6):975–82. Huang J, Xie D, Xiong R, Deng X, Huang C, Fan D, et al. The Application of Suctioning Flexible Ureteroscopy With Intelligent Pressure Control in Treating Upper Urinary Tract Calculi on Patients With a Solitary Kidney. Urology. 2018;111:44–7. Du C, Song L, Wu X, Deng X, Yang Z, Zhu X, et al. A study on the clinical application of a patented perfusion and suctioning platform and ureteral access sheath in the treatment of large ureteral stones below L4 level. Int Urol Nephrol. 2019;51(2):207–13. Deng X, Xie D, Huang X, Huang J, Song L, Du C. Suctioning Flexible Ureteroscopy with Automatic Control of Renal Pelvic Pressure versus Mini PCNL for the Treatment of 2-3-cm Kidney Stones in Patients with a Solitary Kidney. Urol Int. 2022;106(12):1293–7. Chen W, Lu K, Liu C, Weng J, Gao R. 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. J Endourol. 2024;39(2):135–45. Chen H, Zhu Z, Cui Y, Li Y, Chen Z, Yang Z, et al. Suctioning semirigid ureteroscopic lithotomy versus minimally invasive percutaneous nephrolithotomy for large upper ureteral stones: a retrospective study. Translational Androl Urol. 2021;10(3):1056–63. Giulioni C, Castellani D, Somani BK, Chew BH, Tailly T, Keat WOL, et al. The efficacy of retrograde intra-renal surgery (RIRS) for lower pole stones: results from 2946 patients. World J Urol. 2023;41(5):1407–13. Uslu M, Yildirim Ü, Ezer M, Arslan ÖE, Yaşar H, Sarica K. Comparison of tip-bendable aspiration-assisted and standard access sheaths in the treatment of lower calyceal stones. Rev Assoc Med Bras (1992). 2024;70(12):e20241033. Liang H, Liang L, Lin Y, Yu Y, Xu X, Liang Z, et al. Application of tip-bendable ureteral access sheath in flexible ureteroscopic lithotripsy: an initial experience of 224 cases. BMC Urol. 2023;23(1):175. Yu Y, Chen Y, Zhou X, Li X, Liu W, Cheng X, et al. Comparison of novel flexible and traditional ureteral access sheath in retrograde intrarenal surgery. World J Urol. 2024;42(1):7. Negrete-Pulido O, Gutierrez-Aceves J. Management of infectious complications in percutaneous nephrolithotomy. J Endourol. 2009;23(10):1757–62. Qian X, Liu C, Hong S, Xu J, Qian C, Zhu J, et al. Application of Suctioning Ureteral Access Sheath during Flexible Ureteroscopy for Renal Stones Decreases the Risk of Postoperative Systemic Inflammatory Response Syndrome. Int J Clin Pract. 2022;2022:9354714. Tables Table 1 and 2 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Tables.docx Table 1. Baseline characteristics of participants This table includes age, sex distribution, body mass index (BMI), comorbidities, ASA classification, laterality, stone type and location, stone size and density, preoperative laboratory values (serum creatinine and WBC), hydronephrosis grade, and pre-stenting status. Statistical comparisons were made between the traditional UAS and S-UAS groups. Table 2. Primary and secondary outcomes Outcomes assessed include immediate and 1-month SFR with 4 mm and 2 mm thresholds, operative time, postoperative hospital stay, need for auxiliary procedures, complication types and rates, postoperative renal function and WBC count, and stone composition distribution. Statistical comparisons are reported between the two groups. Supplement.docx Cite Share Download PDF Status: Published Journal Publication published 19 Dec, 2025 Read the published version in BMC Urology → Version 1 posted Editorial decision: Revision requested 08 Jul, 2025 Reviews received at journal 07 Jul, 2025 Reviews received at journal 22 Jun, 2025 Reviewers agreed at journal 16 Jun, 2025 Reviewers agreed at journal 14 Jun, 2025 Reviewers invited by journal 12 Jun, 2025 Editor invited by journal 30 May, 2025 Editor assigned by journal 28 May, 2025 Submission checks completed at journal 28 May, 2025 First submitted to journal 24 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6739619","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":471307835,"identity":"45cc5e3c-473a-46e6-9e1f-e1a55c64280c","order_by":0,"name":"Ting-Yi Chiang","email":"","orcid":"","institution":"Chi Mei Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Ting-Yi","middleName":"","lastName":"Chiang","suffix":""},{"id":471307836,"identity":"ed0c5d06-695f-430d-af75-5e8c37f185fd","order_by":1,"name":"Kau-Han Lee","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAxUlEQVRIiWNgGAWjYBACCQYGNiBlkwDmJRQQryUtAUwlGBCv5TBECwMxWiTbz5g9+LnjfB6/fHfihwcGDPL8Ygfwa5HmyTE37D1zu1iyjXezBNBhhjNnJ+DXIseQYybB23Y7ccMx3g0gLQkGtwlp4X9jJvm37RxIy+YfRGmRlsgxk+ZtOwDSso04WyRnPCuTlm1LTpzZlrvNIsFAgrBfJM4nb5N822aX2M98dvPNHxU28vzSBLRgGEGa8lEwCkbBKBgF2AEAj/g/sYnsWX8AAAAASUVORK5CYII=","orcid":"","institution":"Chi Mei Medical Center","correspondingAuthor":true,"prefix":"","firstName":"Kau-Han","middleName":"","lastName":"Lee","suffix":""},{"id":471307837,"identity":"9c945bc0-add4-44a5-bfe1-7d11f1e46aa7","order_by":2,"name":"Chia-Chih Hsieh","email":"","orcid":"","institution":"Chi Mei Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Chia-Chih","middleName":"","lastName":"Hsieh","suffix":""},{"id":471307838,"identity":"4a38caf5-6e4e-480c-9589-82c4d36f3d7c","order_by":3,"name":"Zhi-Hao Chen","email":"","orcid":"","institution":"Chi Mei Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Zhi-Hao","middleName":"","lastName":"Chen","suffix":""},{"id":471307839,"identity":"538b309e-d742-4aa2-94b6-efdf20cff0de","order_by":4,"name":"Steven K. Huang","email":"","orcid":"","institution":"Chi Mei Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Steven","middleName":"K.","lastName":"Huang","suffix":""},{"id":471307840,"identity":"ed9c45fe-be4b-4423-a651-2fc46b4923a4","order_by":5,"name":"Allen W. Chiu","email":"","orcid":"","institution":"Shin Kong Wu Ho-Su Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Allen","middleName":"W.","lastName":"Chiu","suffix":""}],"badges":[],"createdAt":"2025-05-24 14:38:04","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6739619/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6739619/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12894-025-01976-4","type":"published","date":"2025-12-19T15:57:14+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":98813840,"identity":"68090ca7-a16c-40a3-a545-98a0f7bf8901","added_by":"auto","created_at":"2025-12-22 16:04:46","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":472081,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6739619/v1/c66af102-1f26-491b-867a-0e35b56f6609.pdf"},{"id":84670034,"identity":"9d05d97d-05c3-43aa-93a5-051d1c26b3a5","added_by":"auto","created_at":"2025-06-16 06:34:16","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":24648,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTable 1. Baseline characteristics of participants\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis table includes age, sex distribution, body mass index (BMI), comorbidities, ASA classification, laterality, stone type and location, stone size and density, preoperative laboratory values (serum creatinine and WBC), hydronephrosis grade, and pre-stenting status. Statistical comparisons were made between the traditional UAS and S-UAS groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2. Primary and secondary outcomes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOutcomes assessed include immediate and 1-month SFR with 4 mm and 2 mm thresholds, operative time, postoperative hospital stay, need for auxiliary procedures, complication types and rates, postoperative renal function and WBC count, and stone composition distribution. Statistical comparisons are reported between the two groups.\u003c/p\u003e","description":"","filename":"Tables.docx","url":"https://assets-eu.researchsquare.com/files/rs-6739619/v1/83be3f8b5cb2dba7cb4ac3a4.docx"},{"id":84670036,"identity":"a406e509-25b1-4860-88c7-9d8b118e5037","added_by":"auto","created_at":"2025-06-16 06:34:16","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":25202,"visible":true,"origin":"","legend":"","description":"","filename":"Supplement.docx","url":"https://assets-eu.researchsquare.com/files/rs-6739619/v1/a94d807df8a2b49a4ef188c0.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparative Study of Ureteral Access Sheath versus Suction Access Sheath in Retrograde Intrarenal Surgery","fulltext":[{"header":"Introduction","content":"\u003cp\u003eRetrograde intrarenal surgery (RIRS) has become a cornerstone in the management of renal and upper ureteral stones, offering a minimally invasive alternative to percutaneous nephrolithotomy (PCNL). According to the European Association of Urology (EAU) guidelines, RIRS is recommended for kidney stones \u0026lt; 20 mm in size and, in certain cases, for lower pole stones \u0026gt; 10 mm(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). A critical component of successful RIRS is the use of ureteral access sheaths (UAS), which facilitate repeated instrument access, reduce intrarenal pressure, and enhance irrigation flow during surgery(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). However, studies have shown that the use of a UAS does not significantly improve stone-free rates (SFR) or operative duration(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). The limitations of traditional UAS, particularly in effectively clearing stone fragments, have driven the development of innovative solutions, such as the suction ureteral access sheath (S-UAS).\u003c/p\u003e \u003cp\u003eThe S-UAS is distinguished by its excellent flexibility and deformability at the tip, allowing it to passively bend in alignment with the flexible ureteroscope. Furthermore, the S-UAS can be connected to a vacuum suction device, enabling efficient removal of residual stone fragments while further reducing intrarenal pressure. This design has the potential to SFR and minimize complications associated with retrograde intrarenal surgery. Studies have demonstrated the superior performance of S-UAS compared to traditional UAS, with Zhu et al. reporting significantly higher SFRs (81.3% versus 49.4%)(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e), and Wang et al. showing similar improvements (88.73% versus 75.68%), along with a reduction in postoperative fever rates(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eDespite its theoretical advantages, the benefits of the S-UAS in addressing variations in stone size, location, and complexity have been rarely explored. This study aims to share our experience in managing upper tract stones by retrospectively comparing the outcomes of traditional UAS and S-UAS in RIRS. Key outcomes assessed include immediate and delayed SFRs, operative time, postoperative complications, and the necessity for auxiliary procedures. By performing detailed subgroup analyses, this study seeks to provide a comprehensive evaluation of the clinical utility of S-UAS.\u003c/p\u003e "},{"header":"Methods","content":"\u003cp\u003eThis retrospective cohort study was conducted at Chimei Medical Center between January 2022 and December 2024. It aimed to compare the efficacy and safety of traditional ureteral access sheath (UAS) and suction ureteral access sheath (S-UAS) in retrograde intrarenal surgery (RIRS). Patients were identified from electronic medical records and included if they met the following criteria: adults aged 18 years or older with renal or upper ureteral stones, confirmed by non-contrast computed tomography (CT) imaging, with stone diameters \u0026le;30 mm. Patients with abnormal urinary tract anatomy (e.g., horseshoe kidney), active urinary tract infections, contraindications for RIRS, or those undergoing concurrent surgical procedures such as percutaneous nephrolithotomy (PCNL) were excluded. Additionally, cases with incomplete data or failure to complete the assigned procedure were excluded.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;A total of 121 patients were initially identified, but after exclusions for reasons such as anatomical challenges or procedural changes, 104 patients were included in the final analysis. These were divided into the traditional UAS group (n=53) and the S-UAS group (n=51). Baseline demographic and clinical data, including age, gender, body mass index (BMI), stone characteristics (location, size, and density), and preoperative laboratory values, were collected.\u003c/p\u003e\n\u003cp\u003eAll surgeries were performed by experienced urologists using standardized protocols under general anesthesia. Preoperative imaging consisted of 2-mm non-contrast CT scans to assess stone size and density. Stone size was defined by both the maximum diameter of the largest stone and the cumulative sum of all stone diameters. Stone density was measured in Hounsfield units (HU). Traditional UAS cases predominantly employed manual irrigation with a 50 cc syringe and nitinol stone baskets for fragment retrieval. In contrast, the S-UAS group used a suction-assisted sheath with adjustable suction pressures (50\u0026ndash;100 mmHg) to facilitate stone aspiration during fragmentation.\u003c/p\u003e\n\u003cp\u003eFlexible ureteroscopes of varying sizes (7.5\u0026ndash;9.5 F) were utilized according to sheath dimensions. Holmium laser lithotripsy was employed with settings adjusted for dusting, fragmentation, or popcorn modes, depending on stone size and composition. Postoperative double-J stents were routinely placed and removed 1\u0026ndash;2 weeks after surgery. Immediate stone-free status was assessed via endoscopy and imaging (kidney-ureter-bladder X-ray [KUB] and ultrasound) within 24 hours, while follow-up imaging at one month further evaluated residual stone fragments.\u003c/p\u003e\n\u003cp\u003eThe primary outcomes were immediate stone-free rates (SFRs) defined as the absence of stone fragments \u0026gt;4 mm and \u0026gt;2 mm. Secondary outcomes included SFRs at one month, operative time (defined from ureteroscope insertion to stent placement), hospital stay duration, auxiliary procedures, and complications. Statistical analyses were performed using SPSS version 25.0. Continuous variables were compared using independent t-tests or Mann-Whitney U-tests as appropriate, while categorical variables were analyzed using Chi-square or Fisher\u0026rsquo;s exact tests. Subgroup analyses explored outcomes based on stone size, location, and type.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eBaseline demographic and clinical characteristics, including age, gender distribution, BMI, comorbidities, American Society of Anesthesiologists (ASA) classification, stone laterality, stone type, stone location, and stone size, were comparable between the two groups, with no statistically significant differences observed. The mean stone diameter was 14.27 \u0026plusmn; 6.96 mm in the traditional UAS group and 13.74 \u0026plusmn; 6.53 mm in the S-UAS group (p = 0.689). The preoperative serum creatinine levels and initial positive urine culture rates were also similar between groups. (Table 1)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.1 Primary Outcomes\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe immediate stone-free rate (SFR), defined as the absence of residual stones \u0026gt;4 mm on postoperative imaging, was significantly higher in the S-UAS group (82.0%) compared to the traditional UAS group (60.4%) (p = 0.016). When considering a stricter threshold of 2 mm for SFR assessment, the S-UAS group still demonstrated superior clearance (70.0% vs. 50.9%, p = 0.048). At one month postoperatively, SFR at the 4 mm threshold remained higher in the S-UAS group (85.7% vs. 75.5%), but this difference did not reach statistical significance (p = 0.193). Similarly, the one-month SFR at the 2 mm threshold was comparable between groups (73.5% vs. 67.9%, p = 0.539). (Table 2)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.2 Secondary Outcomes\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eOperative time did not differ significantly between the two groups, with a mean duration of 95.9 \u0026plusmn; 49.8 minutes in the S-UAS group and 98.4 \u0026plusmn; 40.85 minutes in the traditional UAS group (p = 0.781). Postoperative hospital stay was also comparable, with a mean duration of 3.0 \u0026plusmn; 3.69 days in the S-UAS group and 2.79 \u0026plusmn; 2.32 days in the traditional UAS group (p = 0.733). Notably, the need for auxiliary procedures, such as extracorporeal shockwave lithotripsy (ESWL) or secondary endoscopic procedures, was significantly lower in the S-UAS group (5.9%) compared to the traditional UAS group (22.6%, p = 0.015).\u003c/p\u003e\n\u003cp\u003eRegarding safety outcomes, the overall complication rates were low in both groups, with no statistically significant differences. Urosepsis was observed in 2.0% of patients in the S-UAS group and 3.8% in the traditional UAS group. Mucosal tear occurred in 3.8% of patients in the traditional UAS group, whereas no cases were reported in the S-UAS group. Bleeding complications were minimal, with a single case (1.9%) reported in the traditional UAS group and none in the S-UAS group. One case of ureteral stricture was noted in the S-UAS group.\u003c/p\u003e\n\u003cp\u003ePostoperative renal function was assessed through serum creatinine measurements on postoperative day 1 and at three months. No significant differences were observed between the groups, suggesting that the use of S-UAS did not negatively impact renal function recovery. (Table 2)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.3 Subgroup Analysis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eA subgroup analysis was performed to evaluate the efficacy of S-UAS in different stone sizes, stone locations, and stone burden.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.3.1 Stone Size (Cutoff at 15 mm)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eFor patients with large stones (\u0026gt;15 mm), the immediate SFR was significantly higher in the S-UAS group (81.3%) compared to the traditional UAS group (40.0%) (p = 0.018). This trend was not observed in patients with stones \u0026le;15 mm, where SFR differences between the two groups were not statistically significant. (Supplement Table S1)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.3.2 Stone Size (Cutoff at 20 mm)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003ePatients were stratified based on sum of stone size, with a cutoff value of 20 mm to assess whether S-UAS is particularly beneficial for larger stone burdens. In patients with stones \u0026gt;20 mm, the immediate SFR was significantly higher in the S-UAS group compared to the traditional UAS group. In contrast, for patients with stones \u0026le;20 mm, SFR was not significantly different between the two groups. (Supplement Table S2)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.3.3 Stone Number\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eWhen analyzing the impact of stone number, the S-UAS group showed significantly better outcomes in patients with single stones, achieving a 100% immediate SFR compared to 66.7% in the traditional UAS group (p = 0.008). However, in cases of multiple stones, SFR was higher in the S-UAS group (71.9%) compared to the traditional UAS group (57.9%), but the difference was not statistically significant (p = 0.224). (Supplement Table S3)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.3.4 Stone Location\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe S-UAS group demonstrated a significant advantage in clearing lower calyx stones, with an immediate SFR of 81.8% compared to 55.2% in the traditional UAS group (p = 0.046). For stones located in other areas, including the renal pelvis, upper/middle calyx, upper ureter, or staghorn/multiple locations, no significant differences in SFR were found between the groups. (Supplement Table S4)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.3.5 Postoperative White Blood Cell (WBC) Counts\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eTo further explore the postoperative inflammatory response, we compared preoperative and postoperative WBC counts. While preoperative WBC levels were slightly lower in the S-UAS group, postoperative WBC changes were not significantly different between groups, suggesting that S-UAS did not result in a markedly different inflammatory or infectious response compared to traditional UAS.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study highlights the real-world clinical relevance of the S-UAS in enhancing immediate stone clearance during RIRS compared to traditional UAS. Our retrospective analysis of 104 patients demonstrated a significantly higher immediate stone-free rate in the S-UAS group while maintaining comparable complication rates. Additionally, the need for auxiliary procedures was significantly lower in the S-UAS group, indicating improved procedural efficiency. Notably, our subgroup analysis revealed that S-UAS was particularly effective in managing large stones, single stones, and lower calyx stones, providing valuable guidance for optimizing clinical decision-making and surgical approaches.\u003c/p\u003e \u003cp\u003eThe implementation of S-UAS in RIRS has demonstrated increased efficacy, primarily through mechanisms such as the removal of debris, which enhances intraoperative visibility by mitigating the \"snow-globe effect\" and facilitating the identification of concealed fragments. This improvement in visualization contributes to higher immediate SFRs(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). Previous studies have reported increased SFRs both immediately and at three months postoperatively, typically defining SFR as residual fragments smaller than 4 mm on KUB imaging, with the overall SFR ranged higher from 87.5% upwards(\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). In our study, we adopted a more stringent criterion by defining SFR as the absence of residual fragments larger than 2 mm on KUB imaging. This approach revealed a significant improvement in immediate SFR with the use of S-UAS. However, this significance did not persist at the one-month follow-up. This observation may be attributed to the natural clearance of small residual fragments through urination in patients treated with traditional UAS, thereby diminishing the immediate advantage observed with S-UAS.\u003c/p\u003e \u003cp\u003eThe aspiration capability of S-UAS not only enhances immediate stone clearance but also reduces the incidence of steinstrasse and the necessity for auxiliary procedures such as ESWL or secondary ureteroscopy. This reduction in additional interventions potentially contributes to a smoother postoperative recovery and an improvement in patients' quality of life(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). Moreover, the effective aspiration of debris by S-UAS minimizes the need for fragment extraction using stone baskets, thereby streamlining the procedure.\u003c/p\u003e \u003cp\u003eWhile other studies have reported a decrease in operative time with the use of S-UAS(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e), our findings did not demonstrate a significant reduction in surgery duration. This discrepancy may result from the additional time required to maneuver the suctional tip into the lower calyx. With increased experience and proficiency at our center, it is anticipated that this aspect of the procedure may become more efficient, potentially leading to shorter operative times in future studies.\u003c/p\u003e \u003cp\u003eAdvancements in RIRS technology have led to an increasing preference for endoscopic management of larger renal calculi. A feasibility study evaluating a novel tip-flexible suction ureteral access sheath (NTFS-UAS) in combination with flexible ureteroscopic lithotripsy for kidney stones\u0026thinsp;\u0026ge;\u0026thinsp;30 mm demonstrated promising outcomes, reporting immediate and 1-month SFRs of 83.98% and 85.44%, respectively. Multivariate analysis identified stone size (\u0026ge;\u0026thinsp;50 mm), multiple stones, and severe hydronephrosis as independent risk factors negatively affecting stone clearance rates.(\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eOur subgroup analysis further supports these findings, indicating that patients with a single stone larger than 15 mm or a cumulative stone diameter exceeding 20 mm achieved significantly better SFRs with the use of S-UAS. Moreover, improved SFR was observed for single stones, consistent with previous research. This suggests that S-UAS may be particularly beneficial in patients with a substantial stone burden, thereby expanding the applicability of RIRS for managing larger renal stones.\u003c/p\u003e \u003cp\u003eFurthermore, Chen et al. compared suctioning semirigid ureteroscopic lithotomy (Sotn-URSL) with minimally invasive percutaneous nephrolithotomy (mPCNL) and reported an SFR of 84.6% in the Sotn-URSL group versus 92.3% in the mPCNL group, with the difference not reaching statistical significance (P\u0026thinsp;=\u0026thinsp;0.34). Additionally, the Sotn-URSL group experienced shorter hospital stays and fewer complications compared to the mPCNL group.(\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e) Based on these findings, S-UAS could be considered a viable alternative to mPCNL for patients with single renal stones measuring 20\u0026ndash;50 mm, offering a less invasive option with comparable stone clearance outcomes.\u003c/p\u003e \u003cp\u003eRIRS presents significant challenges in the management of lower calyceal stones due to the acute infundibulopelvic angle, which limits access and increases the need for frequent stone basket manipulation. These factors can complicate stone retrieval and prolong operative time, potentially impacting surgical efficiency and outcomes.(\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e) In our study, the use of S-UAS resulted in a significantly higher SFR for lower calyx stones compared to traditional UAS. The incorporation of a bendable tip in S-UAS facilitates precise navigation into the targeted calyx, overcoming anatomical challenges associated with the lower pole. Additionally, the continuous suction mechanism enhances fragment evacuation, reducing residual stone burden and improving immediate clearance. Notably, prior studies evaluating tip-bendable UAS without suction have reported lower SFRs and increased reliance on stone baskets in the lower calyx subgroup.(\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e) This suggests that while tip flexibility enhances maneuverability, the suction mechanism provides an additional advantage in fragment clearance.\u003c/p\u003e \u003cp\u003eThe application of S-UAS during RIRS offers significant advantages in managing intrarenal pressure (IRP) and enhancing irrigation flow. Effective regulation of IRP is crucial, as elevated pressures can lead to pyelovenous backflow, increasing the risk of mucosal injury within the collecting system and facilitating the reabsorption of irrigation fluid containing bacteria and endotoxins, potentially resulting in postoperative infectious complications such as sepsis.(\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e) In our study, the use of S-UAS was associated with comparable overall complication rates to traditional UAS, with a lower incidence of postoperative urosepsis observed in the S-UAS group. Specifically, one patient in the S-UAS group developed urinary retention and fever following Foley catheter removal, which was later diagnosed as underactive bladder. In contrast, two patients in the traditional UAS group developed postoperative urinary tract infections.\u003c/p\u003e \u003cp\u003eNotably, our study found no significant elevation in postoperative WBC counts in the S-UAS group compared to the traditional UAS group, indicating that the rate of sepsis was controlled and aligned with previous studies. This aligns with findings from other studies, such as one that demonstrated the application of suctioning UAS during flexible ureteroscopy was associated with lower incidence of postoperative fever or systemic inflammatory response syndrome (SIRS). (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e) These observations underscore the importance of patient selection and preoperative optimization to mitigate the risk of infectious complications. Further studies are warranted to monitor IRP during S-UAS use and to establish protocols that ensure patient safety and optimal outcomes.\u003c/p\u003e \u003cp\u003eThis study has several limitations due to its retrospective design. The small sample size limits generalizability, especially for complex subgroups, such as those with multiple stones or high stone burden. The lack of randomization introduces potential selection bias, as clinical decisions may have influenced the choice of UAS. Additionally, the absence of long-term follow-up restricts evaluation of delayed complications or the natural passage of small residual stones, which could impact the long-term effectiveness of S-UAS. The study also lacked intrarenal pressure monitoring, which could have provided insights into the role of S-UAS in managing intrarenal pressure and preventing complications like sepsis. Lastly, while postoperative complications were assessed, renal functional outcomes, such as glomerular filtration rate (GFR), were not evaluated, which would be crucial for assessing long-term renal implications.\u003c/p\u003e \u003cp\u003eFuture research should employ a prospective, randomized controlled design with a larger cohort to validate these findings and reduce biases. Additionally, studies focusing on intrarenal pressure monitoring during RIRS with S-UAS could provide valuable insights into its safety profile and ability to prevent adverse events such as pyelovenous backflow and sepsis.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, this study demonstrates that the S-UAS significantly improves immediate SFR during RIRS compared to the traditional UAS. The use of S-UAS was particularly beneficial for larger stones, single stones, and lower calyx stones, contributing to enhanced procedural efficiency and reduced need for auxiliary procedures. Although the S-UAS group showed a higher incidence of postoperative sepsis, complication rates were otherwise similar between groups. While no significant difference in operative time or hospital stay was observed, the improved SFR and reduced need for additional procedures suggest that S-UAS can optimize outcomes in RIRS, especially for challenging stone burdens. Further prospective studies with larger cohorts are needed to confirm these findings and explore the long-term benefits and safety of S-UAS.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eRIRS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eRetrograde Intrarenal Surgery\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eUAS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eUreteral Access Sheath\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eS-UAS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSuction Ureteral Access Sheath\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSFR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eStone-Free Rate\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePCNL\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ePercutaneous Nephrolithotomy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eComputed Tomography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eHU\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eHounsfield Unit\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eWBC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eWhite Blood Cell\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eIRP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eIntrarenal Pressure\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eASA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAmerican Society of Anesthesiologists\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eKUB\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eKidney, Ureter, and Bladder radiograph\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eURSSM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eUreterorenoscopic Stone Surgery Manipulation\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003ch2\u003eConflict of Interest Statement\u003c/h2\u003e\n\u003cp\u003eThe authors certify that they have NO affiliations with or involvement in any organization or entity with any financial interest, or non-financial interest in the subject matter or materials discussed in this manuscript.\u003c/p\u003e\n\u003ch2\u003eEthics approval and consent to participate\u003c/h2\u003e\n\u003cp\u003eThis study was approved by the Institutional Review Board of Chi Mei Medical Center (IRB No. T34763). The requirement for informed consent was waived due to the retrospective nature of the study. All procedures were conducted in accordance with the ethical standards of the institutional and national research committee and with the 2013 Declaration of Helsinki.\u003c/p\u003e\n\u003ch2\u003eConsent for publication\u003c/h2\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThis research received no external funding.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eTYC designed the study, collected and analyzed the data, and drafted the manuscript. KHL supervised the methodology and critically revised the manuscript. CCH, ZHC, SKH, and AWC contributed to data interpretation, figure generation, and manuscript refinement. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgements\u003c/h2\u003e\n\u003cp\u003eThe authors would like to thank the nursing and administrative staff of the Urology Department at Chi Mei Medical Center for their assistance in patient care and data collection. The authors also appreciate the statistical guidance provided by the hospital\u0026rsquo;s Biostatistics Core Facility.\u003c/p\u003e\n\u003ch2\u003eAvailability of data and materials\u003c/h2\u003e\n\u003cp\u003eThe datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003ch2\u003eCompeting interests\u003c/h2\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eT\u0026uuml;rk C, Petř\u0026iacute;k A, Sarica K, Seitz C, Skolarikos A, Straub M, et al. EAU Guidelines on Interventional Treatment for Urolithiasis. Eur Urol. 2016;69(3):475\u0026ndash;82.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZeng G, Traxer O, Zhong W, Osther P, Pearle MS, Preminger GM, et al. International Alliance of Urolithiasis guideline on retrograde intrarenal surgery. BJU Int. 2023;131(2):153\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhu W, Liu S, Cao J, Wang H, Liang H, Jiang K, et al. Tip bendable suction ureteral access sheath versus traditional sheath in retrograde intrarenal stone surgery: an international multicentre, randomized, parallel group, superiority study. EClinicalMedicine. 2024;74:102724.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang L, Zhou Z, Gao P, Yang Y, Ding Q, Wu Z. Comparison of traditional and suctioning ureteral access sheath during retrograde intrarenal surgery in the treatment of renal calculi. Langenbecks Arch Surg. 2024;409(1):81.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYuen SKK, Traxer O, Wroclawski ML, Gadzhiev N, Chai CA, Lim EJ et al. Scoping Review of Experimental and Clinical Evidence and Its Influence on Development of the Suction Ureteral Access Sheath. Diagnostics (Basel). 2024;14(10).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGauhar V, Traxer O, Castellani D, Sietz C, Chew BH, Fong KY, et al. Could Use of a Flexible and Navigable Suction Ureteral Access Sheath Be a Potential Game-changer in Retrograde Intrarenal Surgery? Outcomes at 30 Days from a Large, Prospective, Multicenter, Real-world Study by the European Association of Urology Urolithiasis Section. Eur Urol Focus. 2024;10(6):975\u0026ndash;82.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang J, Xie D, Xiong R, Deng X, Huang C, Fan D, et al. The Application of Suctioning Flexible Ureteroscopy With Intelligent Pressure Control in Treating Upper Urinary Tract Calculi on Patients With a Solitary Kidney. Urology. 2018;111:44\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDu C, Song L, Wu X, Deng X, Yang Z, Zhu X, et al. A study on the clinical application of a patented perfusion and suctioning platform and ureteral access sheath in the treatment of large ureteral stones below L4 level. Int Urol Nephrol. 2019;51(2):207\u0026ndash;13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDeng X, Xie D, Huang X, Huang J, Song L, Du C. Suctioning Flexible Ureteroscopy with Automatic Control of Renal Pelvic Pressure versus Mini PCNL for the Treatment of 2-3-cm Kidney Stones in Patients with a Solitary Kidney. Urol Int. 2022;106(12):1293\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen W, Lu K, Liu C, Weng J, Gao R. 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\u0026thinsp;\u0026ge;\u0026thinsp;30 mm. J Endourol. 2024;39(2):135\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen H, Zhu Z, Cui Y, Li Y, Chen Z, Yang Z, et al. Suctioning semirigid ureteroscopic lithotomy versus minimally invasive percutaneous nephrolithotomy for large upper ureteral stones: a retrospective study. Translational Androl Urol. 2021;10(3):1056\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGiulioni C, Castellani D, Somani BK, Chew BH, Tailly T, Keat WOL, et al. The efficacy of retrograde intra-renal surgery (RIRS) for lower pole stones: results from 2946 patients. World J Urol. 2023;41(5):1407\u0026ndash;13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUslu M, Yildirim \u0026Uuml;, Ezer M, Arslan \u0026Ouml;E, Yaşar H, Sarica K. Comparison of tip-bendable aspiration-assisted and standard access sheaths in the treatment of lower calyceal stones. Rev Assoc Med Bras (1992). 2024;70(12):e20241033.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiang H, Liang L, Lin Y, Yu Y, Xu X, Liang Z, et al. Application of tip-bendable ureteral access sheath in flexible ureteroscopic lithotripsy: an initial experience of 224 cases. BMC Urol. 2023;23(1):175.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYu Y, Chen Y, Zhou X, Li X, Liu W, Cheng X, et al. Comparison of novel flexible and traditional ureteral access sheath in retrograde intrarenal surgery. World J Urol. 2024;42(1):7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNegrete-Pulido O, Gutierrez-Aceves J. Management of infectious complications in percutaneous nephrolithotomy. J Endourol. 2009;23(10):1757\u0026ndash;62.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQian X, Liu C, Hong S, Xu J, Qian C, Zhu J, et al. Application of Suctioning Ureteral Access Sheath during Flexible Ureteroscopy for Renal Stones Decreases the Risk of Postoperative Systemic Inflammatory Response Syndrome. Int J Clin Pract. 2022;2022:9354714.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 and 2 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-urology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"buro","sideBox":"Learn more about [BMC Urology](http://bmcurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/buro/default.aspx","title":"BMC Urology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Retrograde Intrarenal Surgery (RIRS), Suction Ureteral Access Sheath (S-UAS), Traditional Ureteral Access Sheath (UAS), Stone-Free Rate (SFR)","lastPublishedDoi":"10.21203/rs.3.rs-6739619/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6739619/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction:\u003c/h2\u003e \u003cp\u003eRetrograde intrarenal surgery (RIRS) is a minimally invasive technique for managing renal and upper ureteral stones. Ureteral access sheaths (UAS) facilitate instrument access and reduce intrarenal pressure, but their impact on stone-free rates (SFR) remains debated. Suction ureteral access sheaths (S-UAS) offer improved flexibility and can be connected to suction devices, enhancing stone fragment removal. This study aims to compare the outcomes of traditional UAS and S-UAS in RIRS.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective cohort study was conducted at Chimei Medical Center from January 2022 to December 2024, including 104 patients who underwent RIRS with either traditional UAS (n\u0026thinsp;=\u0026thinsp;53) or S-UAS (n\u0026thinsp;=\u0026thinsp;51). Baseline characteristics, operative time, stone-free rates (SFR), postoperative complications, and the need for auxiliary procedures were analyzed. Subgroup analyses assessed the impact of stone size, location, and number on outcomes.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eImmediate SFR was significantly higher in the S-UAS group (82.0%) compared to the traditional UAS group (60.4%) (p\u0026thinsp;=\u0026thinsp;0.016). At one month, no significant difference was observed between the groups. The S-UAS group required fewer auxiliary procedures (5.9% vs. 22.6%, p\u0026thinsp;=\u0026thinsp;0.015) and demonstrated a higher SFR for lower calyx stones (81.8% vs. 55.2%, p\u0026thinsp;=\u0026thinsp;0.046). Operative time, hospital stay, and complication rates were similar between groups. The incidence of postoperative sepsis was higher in the S-UAS group, though other complications remained comparable.\u003c/p\u003e\u003ch2\u003eDiscussion\u003c/h2\u003e \u003cp\u003eThe S-UAS significantly improved immediate SFR in RIRS, particularly for larger stones, single stones, and lower calyx stones. While postoperative sepsis was more common in the S-UAS group, the overall complication rates were low. The suction capability of the S-UAS enhances stone clearance and reduces the need for additional interventions.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe S-UAS offers significant benefits over traditional UAS in improving immediate SFR, particularly in challenging stone cases. Despite a higher rate of postoperative sepsis, S-UAS appears to be a safe and effective option for RIRS, reducing the need for auxiliary procedures and enhancing procedural efficiency. Further studies are needed to evaluate long-term outcomes and refine patient selection for optimal results.\u003c/p\u003e\u003ch2\u003eClinical trial number:\u003c/h2\u003e \u003cp\u003enot applicable.\u003c/p\u003e","manuscriptTitle":"Comparative Study of Ureteral Access Sheath versus Suction Access Sheath in Retrograde Intrarenal Surgery","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-16 06:34:11","doi":"10.21203/rs.3.rs-6739619/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-08T20:03:54+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-07T15:16:42+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-22T12:40:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"5768819752752146091065914479498505099","date":"2025-06-16T11:55:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"116484876885824480053975843751151125360","date":"2025-06-14T10:34:00+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-12T10:25:48+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-05-30T21:41:25+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-28T12:45:33+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-28T12:42:07+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Urology","date":"2025-05-24T14:23:22+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-urology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"buro","sideBox":"Learn more about [BMC Urology](http://bmcurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/buro/default.aspx","title":"BMC Urology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"565294c7-1da4-4a57-b401-6d0122f6e3f6","owner":[],"postedDate":"June 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-22T15:59:39+00:00","versionOfRecord":{"articleIdentity":"rs-6739619","link":"https://doi.org/10.1186/s12894-025-01976-4","journal":{"identity":"bmc-urology","isVorOnly":false,"title":"BMC Urology"},"publishedOn":"2025-12-19 15:57:14","publishedOnDateReadable":"December 19th, 2025"},"versionCreatedAt":"2025-06-16 06:34:11","video":"","vorDoi":"10.1186/s12894-025-01976-4","vorDoiUrl":"https://doi.org/10.1186/s12894-025-01976-4","workflowStages":[]},"version":"v1","identity":"rs-6739619","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6739619","identity":"rs-6739619","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}