Efficacy of 6.3Fr disposable digital flexible ureteroscope versus 7.5Fr disposable digital flexible ureteroscope in the treatment of upper urinary tract stones < 1.5cm: a randomized controlled trial

Efficacy of 6.3Fr disposable digital flexible ureteroscope versus 7.5Fr disposable digital flexible ureteroscope in the treatment of upper urinary tract stones < 1.5cm: a randomized controlled trial | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Efficacy of 6.3Fr disposable digital flexible ureteroscope versus 7.5Fr disposable digital flexible ureteroscope in the treatment of upper urinary tract stones < 1.5cm: a randomized controlled trial tianfu ding, Yangyang xu, Yang chen, Bo xiao, Jianxing li This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6246490/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 23 Jun, 2025 Read the published version in World Journal of Urology → Version 1 posted 8 You are reading this latest preprint version Abstract Objective To compare the curative effect of 6.3Fr disposable digital flexible ureteroscope and 7.5Fr disposable digital flexible ureteroscope in the treatment of upper urinary tract stones < 1.5cm. Materials and Methods From October 2024 to January 2025, 70 patients with < 1.5cm upper urinary tract calculi in our hospital were randomly divided into 2 groups, 35 patients in 6.3Fr non-sheathing group were treated with 6.3Fr HugeMed disposable electronic ureteroscopic laser lithotripsis. In the 7.5Fr flexible ureteroscope group, 35 cases were treated with 7.5Fr common disposable electronic ureteroscope laser lithotripsis. The stone free rate, the success rate of the first stage operation, the operation time and the postoperative hospital stay were compared between the two groups. Results The operation time of 6.3Fr non-sheath group was shorter than that of 7.5 flexible ureteroscope group, and the difference was statistically significant ( P = 0.011). The success rate of the first stage operation was 100% in the 6.3Fr non-sheath group and 91.43% in the 7.5Fr flexible ureteroscope group, with no statistical significance ( P > 0.05). There were no significant differences in stone free rate, laser working time, hemoglobin decline on the first day after surgery, creatinine increase, postoperative hospitalization days and postoperative complications between the two groups ( P > 0.05). Conclusion In conclusion, the sheathless technique using the 6.3Fr disposable digital flexible ureteroscope is safe and effective for upper urinary calculi < 1.5 cm. Further investigations are warranted to evaluate its role in managing larger stones and other urological conditions. Disposable digital flexible ureteroscope Ureteral access sheaths Intrapelvic pressure Retrograde intrarenal surgery Figures Figure 1 Introduction The ureteroscope has emerged as the preferred tool for treating upper urinary tract stones ≤ 2 cm in diameter, gaining widespread clinical favor due to its high stone-free rate, minimally invasive nature, and rapid postoperative recovery. However, during the initial development of fiber-optic flexible ureteroscopes, technical limitations—such as bulky design, insufficient image resolution, excessive outer diameter, and restricted distal deflection—significantly hindered the advancement of endourology. With continuous technological advancements, the advent of digital flexible ureteroscopes, particularly disposable digital flexible ureteroscopes, has markedly improved image transmission technology, achieving superior visualization[1].Compared to fiber-optic counterparts, disposable digital flexible ureteroscopes feature a smaller outer diameter, enhanced distal deflection capability, and reduced risk of bacterial residue from repeated sterilization[2].Currently, common disposable digital flexible ureteroscopes on the market have outer diameters of 8.5Fr and 7.5Fr, while an super-fine 6.3Fr disposable digital flexible ureteroscope (hereinafter referred to as the HugeMed disposable digital flexible ureteroscope) has been developed but lacks clinical reports. Therefore, we conducted a prospective randomized controlled study to compare the efficacy of the HugeMed ureteroscope and the conventional 7.5Fr disposable digital flexible ureteroscope in managing upper urinary tract stones < 1.5 cm in diameter at our institution from October 2024 to January 2025. The findings are reported as follows. Materials and Methods This study was approved by the Ethics Committee of Beijing Tsinghua Changgung Hospital (Approval No. 24699-4-01), and all patients provided written informed consent. A prospective randomized controlled trial, eligible patients were included based on:Inclusion criteria:①Aged 18–75 years, regardless of gender;②Imaging-confirmed upper urinary tract calculi (renal and/or proximal ureteral) with total diameter < 1.5 cm;③Ability to comply with study protocols;④Signed informed consent.Exclusion criteria:①Severe cardiopulmonary dysfunction or other surgical contraindications;②Uncontrolled urinary tract infection;③Pregnancy or lactation;④Mental illness or inability to cooperate;⑤Preoperative double-J stent placement;⑥Ipsilateral ureteroscopic procedure within 3 months.From October 2024 to January 2025, 70 patients with upper urinary calculi were enrolled and randomized into two groups:6.3Fr non-sheathing group: Treated with HugeMed disposable electronic flexible ureteroscope;7.5Fr flexible ureteroscope group: Treated with standard 7.5Fr disposable flexible ureteroscope.Each group included 35 patients (40 males, 30 females; mean age 52.31 ± 12.06 years). Stone size (CT-measured) was 1.25 ± 0.23 cm, with no severe hydronephrosis (assessed by ultrasound). Preoperative urine cultures revealed 5 positive cases in the 6.3Fr non-sheathing group (3 Escherichia coli, 1 Pseudomonas aeruginosa, 1 Proteus) and 6 positive cases in the 7.5Fr flexible ureteroscope group (4 E. coli, 2 P. aeruginosa). Antibiotics were administered for 1–3 days, and surgery was delayed until cultures turned negative with improved leukocyturia. Baseline characteristics were comparable between groups ( P > 0.05, Table 1 ). Devices HugeMed Disposable Electronic Flexible Ureteroscope (6.3Fr, Hunan Hongji Medical Technology Co., Ltd., China);Standard Disposable Electronic Flexible Ureteroscope (7.5Fr, Anhui Xingfu Gongchang Medical Equipment Co., Ltd., China);Ureteral Access Sheath (flexible-tip negative-pressure sheath, 10/12Fr, Anhui Xingfu Gongchang Medical Equipment Co., Ltd., China);Super-pulsed Fiber Thulium Laser (150µm, LAkH Medical Equipment (Beijing) Co., Ltd., China) Surgical Procedures: 6.3Fr non-sheathing Group:Under general anesthesia, the patient was placed in the lithotomy position. Gravity irrigation was used to advance the HugeMed disposable electronic flexible ureteroscope transurethrally into the renal pelvis or ureter. For male patients with difficulty accessing the ureter, a guidewire was first placed, and the scope was advanced over the wire. Upon stone visualization, the super-pulsed fiber thulium laser (energy: 0.6–0.8 J, frequency: 30–40 Hz) was used for dusting lithotripsy. Postoperatively, an F6 ureteral stent and urinary catheter were routinely placed. A CT scan was performed within 48 hours to assess residual fragments, followed by a 1-month follow-up with KUB/non-contrast CT for stent removal.7.5Fr flexible ureteroscope Group: Under general anesthesia in the lithotomy position, a safety guidewire was inserted via rigid ureteroscopy. A 10/12Fr flexible-tip negative-pressure sheath (connected to a suction device at -0.01 to -0.02 MPa) was advanced over the guidewire. The standard 7.5Fr disposable flexible ureteroscope was then introduced, with irrigation provided by a pump (flow rate: 50–150 mL/min). Laser lithotripsy parameters matched the non-sheathing group. Postoperative management (stent placement, imaging, and follow-up) was identical to the 6.3Fr non-sheathing group. Outcome Measures : Demographics: Age, BMI, stone diameter, primary success rate (defined as single-session stone clearance without conversion to open surgery);Operative parameters:6.3Fr non-sheathing group: Procedure time (from scope insertion to stent placement);7.5Fr flexible ureteroscope group: Procedure time (from sheath insertion to stent placement);Laser activation duration.Postoperative indices:Hemoglobin drop (Day 1 post-op);Serum creatinine elevation (Day 1 post-op);Hospital stay;Complications (Clavien-Dindo classification).Stone-free status: Initial SFR: CT-confirmed clearance within 48 hours;Final SFR: CT-confirmed clearance at 1-month follow-up (defined as no residual stones or asymptomatic fragments ≤ 2 mm[3]。Stone composition analysis: Infrared spectroscopy. Statistical Methods All analyses were performed using R 4.1.2. Continuous variables were expressed as mean ± SD or median (IQR) based on normality testing (Kolmogorov-Smirnov). Normally distributed data were compared using Student’s t-test, while non-normally distributed data were analyzed with Mann-Whitney U test. Categorical variables were evaluated using Fisher’s exact test or Chi-square test. A two-tailed P < 0.05 was considered statistically significant. Results The 6.3Fr non-sheathing group demonstrated significantly shorter procedure time compared to the 7.5Fr flexible ureteroscope group ( P < 0.05, Table 2 ). A 100% primary success rate was achieved in the 6.3Fr group, whereas 3 patients in the 7.5Fr group failed sheath insertion due to ureteral stricture and required delayed surgery after 2-week stent placement. Stone-free rates were:6.3Fr non-sheathing group: Initial SFR 85.71% (30/35), final SFR 97.14% (34/35);7.5Fr flexible ureteroscope group: Initial SFR 82.86% (29/35), final SFR 94.29% (33/35).No significant differences were observed in laser activation time, postoperative hemoglobin drop, creatinine elevation, or hospital stay between groups (all P > 0.05). Complications included:6.3Fr non-sheathing group: 2 cases of postoperative pain, 1 fever (> 38℃);7.5Fr flexible ureteroscope group: 2 cases of postoperative pain, 2 fevers (> 38℃).All complications resolved with conservative management, and no severe adverse events (e.g., ureteral perforation, major hemorrhage) occurred. After 3-month follow-up, no stone recurrence was detected in either group. Discussion Retrograde intrarenal surgery (RIRS) has emerged as the preferred treatment for upper urinary tract calculi < 2 cm, offering high stone-free rates (SFR), minimal invasiveness, and rapid recovery.Since Bagley[4] first described the modern flexible ureteroscope in 1987, its clinical adoption has grown exponentially. Early iterations faced limitations such as restricted deflection angles and suboptimal image resolution, which were progressively addressed through technical advancements. Post-2000, innovations in imaging technology significantly enhanced visual clarity, transforming RIRS outcomes.Initially, reusable electronic flexible ureteroscopes dominated clinical practice despite drawbacks including exorbitant costs, frequent malfunctions, and prohibitive repair expenses[5].These financial barriers limited their accessibility. The introduction of domestic disposable digital flexible ureteroscopesmarked a paradigm shift. Comparative studies between disposable and reusable systems revealed comparable safety and efficacy in upper urinary tract procedures, with no significant differences in device failure rates, defects, or adverse events[6].Today, disposable digital flexible ureteroscopes have evolved from 9.6Fr, 9.2Fr, 9.0Fr, and 8.5Fr to the current 7.5Fr diameter, driven by miniaturization and precision engineering. These technological breakthroughs have rendered disposable scopes increasingly popular among urologists, combining cost-effectiveness with reliable performance. The HugeMed disposable digital flexible ureteroscope features a super fine outer diameter of 6.3Fr (2.1mm), yet retains a 3.6Fr (1.2mm) working channel equivalent to 7.5Fr or 8.5Fr disposable digital flexible ureteroscopes (Fig. 1 ). This innovation is achieved through advanced miniaturization of the CMOS image sensor and LED light source, while maintaining uncompromised image quality and brightness.Active and passive deflection tests confirmed bidirectional 270° tip deflection, even when loaded with a laser fiber, ensuring optimal access to most lower pole calyces. Additionally, sheath advancement testing[7] demonstrated that the scope’s flexible tip could maintain maximal downward deflection while a negative-pressure sheath was advanced over the scope from the ureteropelvic junction to the stone site—a critical maneuver for real-world clinical scenarios. Compared to 7.5Fr disposable ureteroscopes, the HugeMed scope’s bidirectional deflection capabilities and sheath advancement performance were no inferior. Our experience with using the HugeMed disposable digital flexible ureteroscope is as follows: Thanks to the introduction of the negative pressure sheath technology, flexible ureteroscopic lithotripsy can now effectively treat kidney stones with a diameter exceeding 2 cm[8]. During the surgery in the 6.3Fr non - sheathing group, we did not use a ureteral access sheath. Considering the intraoperative drainage and aiming to shorten the operation time, the diameter of the upper urinary tract stones we treated was generally less than 1.5 cm. In the future, we will attempt to treat stones with larger diameters.In this study, we used a super pulsed fiber thulium laser. Compared with the traditional holmium laser, the fiber diameter of the thulium fiber laser is smaller[9], which significantly reduces the occupancy rate of the working channel and creates more space for perfusion and drainage. Meanwhile, the fine powdering mode can generate smaller stone fragments[10], completely eliminating the risk of damage from the stone basket. When withdrawing the scope, we carefully observed all patients and found no cases of ureteral injury.After the operation, to ensure the patency and recovery of the ureter, we indwelled a DJ tube for the patients and removed it one month later. After follow - up, the final stone - free rate in the 6.3Fr non - sheathing group reached 97.14% (34/35), and no cases of secondary hydronephrosis occurred (follow - up for 3 months). In flexible ureteroscopic lithotripsy, routine use of the ureteral access sheath improves operative stability and stone clearance efficiency, but its insertion success rate is constrained by ureteral anatomy. Our previous institutional data revealed a 20.3% primary sheath failure rate,potentially linked to factors like age and ipsilateral ureteral intervention history[11]. In this study, 3 patients in the 7.5Fr flexible ureteroscope group failed sheath insertion due to ureteral stricture or reduced wall elasticity, necessitating delayed surgery after 2-week stent placement. In contrast, the 6.3Fr non-sheathing group achieved 100% primary success rate using the HugeMed disposable digital flexible ureteroscope. Its ultra-thin design allowed direct passage through strictures without pre-dilation, even in challenging ureters. This resulted in a 97.14% stone-free rate at 30 days, while also reducing healthcare costs and multiple anesthesia risks. Our findings validate the HugeMed scope as a first-line option for patients with difficult ureters, offering both clinical efficacy and health economic advantages. The use of ureteral access sheaths remains controversial. While sheaths offer benefits like improved reflux, reduced intrapelvic pressure, and facilitated scope reinsertion[12],potential drawbacks include ureteral wall trauma during placement[13]、ischemic injury from prolonged compression[14], and increased risk of postoperative strictures[15]. A meta-analysis by Huang J et al.[16] demonstrated no significant differences in stone-free rates, intraoperative complications, procedure time, or hospital stay between sheathed and sheathless RIRS, but reported higher postoperative complication rates in the sheathed group. Similarly, a prospective trial by Panthier F[17] showed safe RIRS outcomes without sheaths, with comparable complication rates.In our study, the 6.3Fr non-sheathing group achieved shorter procedure time than the 7.5Fr flexible ureteroscope group ( P = 0.011), yet complication rates were comparable ( P = 0.691). Health economic analysis highlighted cost savings with sheathless RIRS, primarily due to reduced hospital costs. Notably, bladder drainage was critical for maintaining safe intrapelvic pressure in sheathless cases—we used 8–10Fr urinary catheters to optimize outflow. The magnitude of intrapelvic pressure is closely linked to the duration of surgery and the incidence of infectious complications. Elevated intrapelvic pressure has the potential to cause the backflow of irrigating fluid that contains bacteria and endotoxins into the bloodstream. This, in turn, heightens the risk of postoperative infections, such as fever and sepsis[18–20]. Moreover, an extended surgical time also increases the likelihood of infectious complications. Prolonged surgeries demand more irrigating fluid, which can further raise intrapelvic pressure[18, 21], Therefore, special attention must be paid to the occurrence of infectious complications after sheathless procedures. When using the HugeMed disposable digital flexible ureteroscope, we opt for gravity irrigation. This method allows for low flow perfusion, ensuring clear visibility and preventing thermal injury while maintaining low intrapelvic pressure. Animal experiments by Samaras A et al. [22] showed that when a 7.5Fr disposable digital flexible ureteroscope is used without an access sheath, the intrapelvic pressure measures 28.25 ± 11.2 mmHg, which is within a safe range. Although there are no animal experiments with the finer 6.3Fr disposable flexible ureteroscope, it can be inferred that the intrapelvic pressure will be even lower when using the HugeMed scope. Additionally, when using the laser fiber, which occupies part of the working channel, the reduced water inflow will result in lower intrapelvic pressure[22].In the 6.3Fr non - sheathing group, one patient developed a postoperative fever. The probable causes were identified as the presence of an infectious stone and a relatively long lithotripsy time. Therefore, when using the HugeMed disposable digital flexible ureteroscope, patients should be carefully selected. Antibiotics should be appropriately administered before surgery, and every effort should be made to shorten the operation time. The HugeMed disposable digital flexible ureteroscope minimizes patient trauma, reduces pain, and enhances comfort, facilitating faster postoperative recovery. Currently, we primarily treat smaller stones (< 1.5 cm), but vigilance against intraoperative/postoperative complications is essential. In cases of intrapelvic hypertension-related complications (e.g., fever, sepsis), management strategies include administering targeted antibiotics, monitoring vital signs, and providing intensive care unit (ICU) support when necessary[23]. Notably, male patients with prostatic hyperplasia often require guidewire assistance to access the ureteral orifice after bladder entry, due to anatomical challenges. In contrast, female patients typically allow direct scope insertion into the ureter without additional aids. This study has several limitations. First, only gravity irrigation was used, and there are currently no recommended parameters for perfusion pressure and flow rate. Future research will explore these through in vitro experiments or animal studies. Additionally, the lack of dedicated sheaths suitable for the 6.3Fr scope restricts its application in treating larger stones (> 1.5 cm). In conclusion, the sheathless technique using the 6.3Fr disposable digital flexible ureteroscope is safe and effective for upper urinary calculi < 1.5 cm. Further investigations are warranted to evaluate its role in managing larger stones and other urological conditions. Declarations Author contributions All of the listed authors contributed substantially to the production of this research and manuscript. Funding There was no source of funding for this project. References Doizi S, Kamphuis G, Giusti G, et al. First clinical evaluation of a new single-use flexible ureteroscope (LithoVue™): a European prospective multicentric feasibility study. World J Urol. 2017;35(5):809-18. Ofstead CL, Heymann OL, Quick MR, et al. The effectiveness of sterilization for flexible ureteroscopes: A real-world study. American journal of infection control. 2017;45(8):888-95. Davis RB, Farber NJ, Kaplan A, et al. Contemporary practice patterns in the treatment of pediatric stone disease. The Canadian journal of urology. 2018;25(4):9427-32. Bagley DH. Flexible ureteropyeloscopy with modular, "disposable" endoscope. Urology. 1987;29(3):296-300. Boylu U, Oommen M, Thomas R, et al. In vitro comparison of a disposable flexible ureteroscope and conventional flexible ureteroscopes. The Journal of urology. 2009;182(5):2347-51. Wenbiao L, Guohua Z, Jinchun X, et al. A prospective multicenter randomized controlled clinical trial study of a domestic single-use digital flexible ureteroscope versus a reusable digital flexible ureteroscope for the treatment of upper urinary tract stones. CJU. 2022(05);374-378. Lua A, Tan LRL, Panthier F, et al. Optimal deflection techniques for flexible and navigable suction ureteral access sheaths (FANS): a comparative in vitro PEARLS analysis. World J Urol. 2024;42(1):606. Chen H, Xiao J, Ge J, et al. Clinical efficacy analysis of tip‑flexible suctioning ureteral access sheath combined with disposable flexible ureteroscope to treat 2-4 cm renal stones. International urology and nephrology. 2024;56(10):3193-9. Patel N, Akhavein A, Hinck B, et al. Tipless Nitinol Stone Baskets: Comparison of Penetration Force, Radial Dilation Force, Opening Dynamics, and Deflection. Urology. 2017;103:256-60. Tang X, Wu S, Li Z, et al. Comparison of Thulium Fiber Laser versus Holmium laser in ureteroscopic lithotripsy: a Meta-analysis and systematic review. BMC urology. 2024;24(1):44. Mogilevkin Y, Sofer M, Margel D, et al. Predicting an effective ureteral access sheath insertion: a bicenter prospective study. J Endourol. 2014;28(12):1414-7. Vanlangendonck R, Landman J. Ureteral access strategies: pro-access sheath. The Urologic clinics of North America. 2004;31(1):71-81. Traxer O, Thomas A. Prospective evaluation and classification of ureteral wall injuries resulting from insertion of a ureteral access sheath during retrograde intrarenal surgery. The Journal of urology. 2013;189(2):580-4. Guzelburc V, Guven S, Boz MY, et al. Intraoperative Evaluation of Ureteral Access Sheath-Related Injuries Using Post-Ureteroscopic Lesion Scale. Journal of laparoendoscopic & advanced surgical techniques Part A. 2016;26(1):23-6. Monga M, Bodie J, Ercole B. Is there a role for small-diameter ureteral access sheaths? Impact on irrigant flow and intrapelvic pressures. Urology. 2004;64(3):439-41; discussion 41-2. Huang J, Zhao Z, AlSmadi JK, et al. Use of the ureteral access sheath during ureteroscopy: A systematic review and meta-analysis. PloS one. 2018;13(2):e0193600. Panthier F, Kwok JL, Tzou DT, et al. What is the definition of stone dust and how does it compare with clinically insignificant residual fragments? A comprehensive review. World J Urol. 2024;42(1):292. Traxer O, Wendt-Nordahl G, Sodha H, et al. Differences in renal stone treatment and outcomes for patients treated either with or without the support of a ureteral access sheath: The Clinical Research Office of the Endourological Society Ureteroscopy Global Study. World J Urol. 2015;33(12):2137-44. Michel MS, Honeck P, Alken P. Conventional high pressure versus newly developed continuous-flow ureterorenoscope: urodynamic pressure evaluation of the renal pelvis and flow capacity. J Endourol. 2008;22(5):1083-5. Noureldin YA, Kallidonis P, Ntasiotis P, et al. The Effect of Irrigation Power and Ureteral Access Sheath Diameter on the Maximal Intra-Pelvic Pressure During Ureteroscopy: In Vivo Experimental Study in a Live Anesthetized Pig. J Endourol. 2019;33(9):725-9. Santa Cruz JAC, Danilovic A, Vicentini FC, et al. Ureteral access sheath. Does it improve the results of flexible ureteroscopy? A narrative review. International braz j urol : official journal of the Brazilian Society of Urology. 2024;50(3):346-58. Samaras A, Tatanis V, Peteinaris A, et al. The Evaluation of Intrarenal Pressure Using a Novel Single-Use Flexible Ureteroscope with Live Intrarenal Pressure Monitoring-An Experimental Study in Porcine Models. Life (Basel, Switzerland). 2024;14(9). Haas CR, Li G, Hyams ES, et al. Delayed Decompression of Obstructing Stones with Urinary Tract Infection is Associated with Increased Odds of Death. The Journal of urology. 2020;204(6):1256-62. Tables Table 1. Demographic parameters and stone characteristics Factors Value t （ X 2 ） P 6.3 (n=35) 7.5 (n=35) Age (y) Mean ± SD 51.86 ± 12.89 52.77 ± 11.34 0.315 0.754 BMI (kg/m 2 ) Mean ± SD 22.75 ± 3.77 22.34 ± 3.02 0.503 0.612 Stone size (cm) Mean ± SD 1.21 ± 0.23 1.29 ± 0.19 1.452 0.151 N(%) Gender 0.23 0.629 Femal 16 (45.71) 14 (40) Male 19 (54.29) 21(60) Stone location 0.233 0.629 pelvis 21 (60) 19 (54.29) ureter 14 (40) 16 (45.71) Hydronephrosis 0.484 0.785 None 28 (80) 26 (74.26) Mild 6 (17.14) 7 (20) Moderate or severe 1 (2.86) 2 (5.71) urinary infection 0.107 0.742 Yes 5 (14.26) 6 (17.14) No 30 (85.71) 29 (82.86) 6.3: 6.3Fr non-sheathing group 7.5: 7.5Fr flexible ureteroscope group Table 2. Intraoperative and postoperative data Parameters Value t （ X 2 ） P 6.3 (n=35) 7.5 (n=35) Operative duration (min) Mean ± SD 50.45 ± 19.34 60.52 ± 12.47 2.589 0.011 Laser operating time (min) Mean ± SD 22.47 ± 6.33 23.53 ± 5.66 0.741 0.462 Postoperative hospitalization time (day) Mean ± SD 1.37 ± 0.49 1.57 ± 0.61 1.515 0.134 Postoperative Day 1 hemoglobin drop (g/L) Mean ± SD 5.15 ± 2.55 4.85 ± 2.37 0.515 0.609 Postoperative Day 1 Creatinine increase (μmoI/L ) Mean ± SD 10.16 ± 5.25 8.35 ± 4.64 1.530 0.131 First-stage success rate % (N) 100% (35) 91.43% (32) 1.393 0.238 Initial Stone free rate % (N) 85.71% (30) 82.86% (29) 0.108 0.743 Final stone free rate % (N) 97.14% (34) 94.29% (33) 0.348 0.555 N (%) Complications 0.158 0.691 None 32 (91.43) 31 (88.57) Clavien Ⅰ 3 (8.57) 4 (11.43) Clavien Ⅱ-Ⅲ 0 0 Stone Composition 1.296 0.255 Calcium oxalate 25 (71.43) 29 (82.86) Uric acid 2 (5.71) 0 (0) Infection stone 5 (14.29) 4 (11.43) Mixed 3 (8.57) 2 (5.71) 6.3: 6.3Fr non-sheathing group 7.5: 7.5Fr flexible ureteroscope group Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 23 Jun, 2025 Read the published version in World Journal of Urology → Version 1 posted Editorial decision: Revision requested 10 Apr, 2025 Reviews received at journal 28 Mar, 2025 Reviewers agreed at journal 28 Mar, 2025 Reviewers agreed at journal 27 Mar, 2025 Reviewers invited by journal 27 Mar, 2025 Editor assigned by journal 19 Mar, 2025 Submission checks completed at journal 19 Mar, 2025 First submitted to journal 17 Mar, 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. We do this by developing innovative software and high quality services for the global research community. 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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-6246490","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":441158373,"identity":"fca090f1-c41c-4a71-9ea4-4443c2018a48","order_by":0,"name":"tianfu ding","email":"","orcid":"","institution":"Beijing Tsinghua Chang Gung Hospital","correspondingAuthor":false,"prefix":"","firstName":"tianfu","middleName":"","lastName":"ding","suffix":""},{"id":441158374,"identity":"5f62b2ac-e320-4e04-9d07-6ba460ec246a","order_by":1,"name":"Yangyang xu","email":"","orcid":"","institution":"Beijing Tsinghua Chang Gung Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yangyang","middleName":"","lastName":"xu","suffix":""},{"id":441158375,"identity":"10746437-ae81-40a7-a410-140dc36038b6","order_by":2,"name":"Yang chen","email":"","orcid":"","institution":"Beijing Tsinghua Chang Gung Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yang","middleName":"","lastName":"chen","suffix":""},{"id":441158376,"identity":"7bef4934-06a4-42bf-b69d-a1405bf14397","order_by":3,"name":"Bo xiao","email":"","orcid":"","institution":"Beijing Tsinghua Chang Gung Hospital","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"","lastName":"xiao","suffix":""},{"id":441158377,"identity":"b1e6eb64-077e-4601-a1aa-b2005c874733","order_by":4,"name":"Jianxing li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA90lEQVRIie2Rv2rDMBCHZQTKcqlWGdJ3UCk0BEzyKhIBT32AjgKDtu7u1qcoGU8YOpl6DWSxHyBgbym0UNE/ZJM6FqpvOXHcx+8OEZJI/EEuKFHoKxBCEfVbAZybsMLOCtP9YMpFXmNEOT/h+mowTSGNiigzMuDrrlks+eON0LsOJMFsnG7Di7n7toRV3ZdCtwdYUkPzh6fILXNbgNzjs1DsACuDjM4jinu3wivOeuUFJKq40nymdBWV2uIvlUtb+hSW9ardQl67KngL5+12OtpmI7tudKe79Ybzyo1TQPHfob6qUD+dzITmPTP8zsPIYCKRSPxbPgB0HFVRzWcLzgAAAABJRU5ErkJggg==","orcid":"","institution":"Beijing Tsinghua Chang Gung Hospital","correspondingAuthor":true,"prefix":"","firstName":"Jianxing","middleName":"","lastName":"li","suffix":""}],"badges":[],"createdAt":"2025-03-17 16:38:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6246490/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6246490/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00345-025-05751-w","type":"published","date":"2025-06-23T15:57:09+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":80820433,"identity":"549025ea-c621-47ac-a2d4-e22e67f282e9","added_by":"auto","created_at":"2025-04-17 12:06:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":227153,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic Diagram of the HugeMed Disposable Digital Flexible Ureteroscope\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6246490/v1/bedb441a9e680ad623abdcd7.png"},{"id":85686185,"identity":"a074857a-e4f0-4179-b5c0-ad93fc7b5416","added_by":"auto","created_at":"2025-06-30 16:04:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1003387,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6246490/v1/74aae166-0878-45f1-8b49-7f75212ebc8c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Efficacy of 6.3Fr disposable digital flexible ureteroscope versus 7.5Fr disposable digital flexible ureteroscope in the treatment of upper urinary tract stones \u003c 1.5cm: a randomized controlled trial","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe ureteroscope has emerged as the preferred tool for treating upper urinary tract stones\u0026thinsp;\u0026le;\u0026thinsp;2 cm in diameter, gaining widespread clinical favor due to its high stone-free rate, minimally invasive nature, and rapid postoperative recovery. However, during the initial development of fiber-optic flexible ureteroscopes, technical limitations\u0026mdash;such as bulky design, insufficient image resolution, excessive outer diameter, and restricted distal deflection\u0026mdash;significantly hindered the advancement of endourology. With continuous technological advancements, the advent of digital flexible ureteroscopes, particularly disposable digital flexible ureteroscopes, has markedly improved image transmission technology, achieving superior visualization[1].Compared to fiber-optic counterparts, disposable digital flexible ureteroscopes feature a smaller outer diameter, enhanced distal deflection capability, and reduced risk of bacterial residue from repeated sterilization[2].Currently, common disposable digital flexible ureteroscopes on the market have outer diameters of 8.5Fr and 7.5Fr, while an super-fine 6.3Fr disposable digital flexible ureteroscope (hereinafter referred to as the HugeMed disposable digital flexible ureteroscope) has been developed but lacks clinical reports.\u003c/p\u003e \u003cp\u003eTherefore, we conducted a prospective randomized controlled study to compare the efficacy of the HugeMed ureteroscope and the conventional 7.5Fr disposable digital flexible ureteroscope in managing upper urinary tract stones\u0026thinsp;\u0026lt;\u0026thinsp;1.5 cm in diameter at our institution from October 2024 to January 2025. The findings are reported as follows.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e This study was approved by the Ethics Committee of Beijing Tsinghua Changgung Hospital (Approval No. 24699-4-01), and all patients provided written informed consent. A prospective randomized controlled trial, eligible patients were included based on:Inclusion criteria:①Aged 18\u0026ndash;75 years, regardless of gender;②Imaging-confirmed upper urinary tract calculi (renal and/or proximal ureteral) with total diameter\u0026thinsp;\u0026lt;\u0026thinsp;1.5 cm;③Ability to comply with study protocols;④Signed informed consent.Exclusion criteria:①Severe cardiopulmonary dysfunction or other surgical contraindications;②Uncontrolled urinary tract infection;③Pregnancy or lactation;④Mental illness or inability to cooperate;⑤Preoperative double-J stent placement;⑥Ipsilateral ureteroscopic procedure within 3 months.From October 2024 to January 2025, 70 patients with upper urinary calculi were enrolled and randomized into two groups:6.3Fr non-sheathing group: Treated with HugeMed disposable electronic flexible ureteroscope;7.5Fr flexible ureteroscope group: Treated with standard 7.5Fr disposable flexible ureteroscope.Each group included 35 patients (40 males, 30 females; mean age 52.31\u0026thinsp;\u0026plusmn;\u0026thinsp;12.06 years). Stone size (CT-measured) was 1.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23 cm, with no severe hydronephrosis (assessed by ultrasound). Preoperative urine cultures revealed 5 positive cases in the 6.3Fr non-sheathing group (3 Escherichia coli, 1 Pseudomonas aeruginosa, 1 Proteus) and 6 positive cases in the 7.5Fr flexible ureteroscope group (4 E. coli, 2 P. aeruginosa). Antibiotics were administered for 1\u0026ndash;3 days, and surgery was delayed until cultures turned negative with improved leukocyturia. Baseline characteristics were comparable between groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05, Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eDevices\u003c/strong\u003e \u003cp\u003eHugeMed Disposable Electronic Flexible Ureteroscope (6.3Fr, Hunan Hongji Medical Technology Co., Ltd., China);Standard Disposable Electronic Flexible Ureteroscope (7.5Fr, Anhui Xingfu Gongchang Medical Equipment Co., Ltd., China);Ureteral Access Sheath (flexible-tip negative-pressure sheath, 10/12Fr, Anhui Xingfu Gongchang Medical Equipment Co., Ltd., China);Super-pulsed Fiber Thulium Laser (150\u0026micro;m, LAkH Medical Equipment (Beijing) Co., Ltd., China)\u003c/p\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSurgical Procedures:\u003c/h2\u003e \u003cp\u003e6.3Fr non-sheathing Group:Under general anesthesia, the patient was placed in the lithotomy position. Gravity irrigation was used to advance the HugeMed disposable electronic flexible ureteroscope transurethrally into the renal pelvis or ureter. For male patients with difficulty accessing the ureter, a guidewire was first placed, and the scope was advanced over the wire. Upon stone visualization, the super-pulsed fiber thulium laser (energy: 0.6\u0026ndash;0.8 J, frequency: 30\u0026ndash;40 Hz) was used for dusting lithotripsy. Postoperatively, an F6 ureteral stent and urinary catheter were routinely placed. A CT scan was performed within 48 hours to assess residual fragments, followed by a 1-month follow-up with KUB/non-contrast CT for stent removal.7.5Fr flexible ureteroscope Group:\u003c/p\u003e \u003cp\u003eUnder general anesthesia in the lithotomy position, a safety guidewire was inserted via rigid ureteroscopy. A 10/12Fr flexible-tip negative-pressure sheath (connected to a suction device at -0.01 to -0.02 MPa) was advanced over the guidewire. The standard 7.5Fr disposable flexible ureteroscope was then introduced, with irrigation provided by a pump (flow rate: 50\u0026ndash;150 mL/min). Laser lithotripsy parameters matched the non-sheathing group. Postoperative management (stent placement, imaging, and follow-up) was identical to the 6.3Fr non-sheathing group.\u003c/p\u003e \u003cp\u003e \u003cb\u003eOutcome Measures\u003c/b\u003e: Demographics: Age, BMI, stone diameter, primary success rate (defined as single-session stone clearance without conversion to open surgery);Operative parameters:6.3Fr non-sheathing group: Procedure time (from scope insertion to stent placement);7.5Fr flexible ureteroscope group: Procedure time (from sheath insertion to stent placement);Laser activation duration.Postoperative indices:Hemoglobin drop (Day 1 post-op);Serum creatinine elevation (Day 1 post-op);Hospital stay;Complications (Clavien-Dindo classification).Stone-free status: Initial SFR: CT-confirmed clearance within 48 hours;Final SFR: CT-confirmed clearance at 1-month follow-up (defined as no residual stones or asymptomatic fragments\u0026thinsp;\u0026le;\u0026thinsp;2 mm[3]。Stone composition analysis: Infrared spectroscopy.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eStatistical Methods\u003c/strong\u003e \u003cp\u003eAll analyses were performed using R 4.1.2. Continuous variables were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD or median (IQR) based on normality testing (Kolmogorov-Smirnov). Normally distributed data were compared using Student\u0026rsquo;s t-test, while non-normally distributed data were analyzed with Mann-Whitney U test. Categorical variables were evaluated using Fisher\u0026rsquo;s exact test or Chi-square test. A two-tailed \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThe 6.3Fr non-sheathing group demonstrated significantly shorter procedure time compared to the 7.5Fr flexible ureteroscope group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05, Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e2\u003c/span\u003e). A 100% primary success rate was achieved in the 6.3Fr group, whereas 3 patients in the 7.5Fr group failed sheath insertion due to ureteral stricture and required delayed surgery after 2-week stent placement. Stone-free rates were:6.3Fr non-sheathing group: Initial SFR 85.71% (30/35), final SFR 97.14% (34/35);7.5Fr flexible ureteroscope group: Initial SFR 82.86% (29/35), final SFR 94.29% (33/35).No significant differences were observed in laser activation time, postoperative hemoglobin drop, creatinine elevation, or hospital stay between groups (all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Complications included:6.3Fr non-sheathing group: 2 cases of postoperative pain, 1 fever (\u0026gt;\u0026thinsp;38℃);7.5Fr flexible ureteroscope group: 2 cases of postoperative pain, 2 fevers (\u0026gt;\u0026thinsp;38℃).All complications resolved with conservative management, and no severe adverse events (e.g., ureteral perforation, major hemorrhage) occurred. After 3-month follow-up, no stone recurrence was detected in either group.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eRetrograde intrarenal surgery (RIRS) has emerged as the preferred treatment for upper urinary tract calculi\u0026thinsp;\u0026lt;\u0026thinsp;2 cm, offering high stone-free rates (SFR), minimal invasiveness, and rapid recovery.Since Bagley[4] first described the modern flexible ureteroscope in 1987, its clinical adoption has grown exponentially. Early iterations faced limitations such as restricted deflection angles and suboptimal image resolution, which were progressively addressed through technical advancements. Post-2000, innovations in imaging technology significantly enhanced visual clarity, transforming RIRS outcomes.Initially, reusable electronic flexible ureteroscopes dominated clinical practice despite drawbacks including exorbitant costs, frequent malfunctions, and prohibitive repair expenses[5].These financial barriers limited their accessibility. The introduction of domestic disposable digital flexible ureteroscopesmarked a paradigm shift. Comparative studies between disposable and reusable systems revealed comparable safety and efficacy in upper urinary tract procedures, with no significant differences in device failure rates, defects, or adverse events[6].Today, disposable digital flexible ureteroscopes have evolved from 9.6Fr, 9.2Fr, 9.0Fr, and 8.5Fr to the current 7.5Fr diameter, driven by miniaturization and precision engineering. These technological breakthroughs have rendered disposable scopes increasingly popular among urologists, combining cost-effectiveness with reliable performance.\u003c/p\u003e \u003cp\u003eThe HugeMed disposable digital flexible ureteroscope features a super fine outer diameter of 6.3Fr (2.1mm), yet retains a 3.6Fr (1.2mm) working channel equivalent to 7.5Fr or 8.5Fr disposable digital flexible ureteroscopes (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). This innovation is achieved through advanced miniaturization of the CMOS image sensor and LED light source, while maintaining uncompromised image quality and brightness.Active and passive deflection tests confirmed bidirectional 270\u0026deg; tip deflection, even when loaded with a laser fiber, ensuring optimal access to most lower pole calyces. Additionally, sheath advancement testing[7] demonstrated that the scope\u0026rsquo;s flexible tip could maintain maximal downward deflection while a negative-pressure sheath was advanced over the scope from the ureteropelvic junction to the stone site\u0026mdash;a critical maneuver for real-world clinical scenarios. Compared to 7.5Fr disposable ureteroscopes, the HugeMed scope\u0026rsquo;s bidirectional deflection capabilities and sheath advancement performance were no inferior.\u003c/p\u003e \u003cp\u003eOur experience with using the HugeMed disposable digital flexible ureteroscope is as follows: Thanks to the introduction of the negative pressure sheath technology, flexible ureteroscopic lithotripsy can now effectively treat kidney stones with a diameter exceeding 2 cm[8]. During the surgery in the 6.3Fr non - sheathing group, we did not use a ureteral access sheath. Considering the intraoperative drainage and aiming to shorten the operation time, the diameter of the upper urinary tract stones we treated was generally less than 1.5 cm. In the future, we will attempt to treat stones with larger diameters.In this study, we used a super pulsed fiber thulium laser. Compared with the traditional holmium laser, the fiber diameter of the thulium fiber laser is smaller[9], which significantly reduces the occupancy rate of the working channel and creates more space for perfusion and drainage. Meanwhile, the fine powdering mode can generate smaller stone fragments[10], completely eliminating the risk of damage from the stone basket. When withdrawing the scope, we carefully observed all patients and found no cases of ureteral injury.After the operation, to ensure the patency and recovery of the ureter, we indwelled a DJ tube for the patients and removed it one month later. After follow - up, the final stone - free rate in the 6.3Fr non - sheathing group reached 97.14% (34/35), and no cases of secondary hydronephrosis occurred (follow - up for 3 months).\u003c/p\u003e \u003cp\u003eIn flexible ureteroscopic lithotripsy, routine use of the ureteral access sheath improves operative stability and stone clearance efficiency, but its insertion success rate is constrained by ureteral anatomy. Our previous institutional data revealed a 20.3% primary sheath failure rate,potentially linked to factors like age and ipsilateral ureteral intervention history[11]. In this study, 3 patients in the 7.5Fr flexible ureteroscope group failed sheath insertion due to ureteral stricture or reduced wall elasticity, necessitating delayed surgery after 2-week stent placement. In contrast, the 6.3Fr non-sheathing group achieved 100% primary success rate using the HugeMed disposable digital flexible ureteroscope. Its ultra-thin design allowed direct passage through strictures without pre-dilation, even in challenging ureters. This resulted in a 97.14% stone-free rate at 30 days, while also reducing healthcare costs and multiple anesthesia risks. Our findings validate the HugeMed scope as a first-line option for patients with difficult ureters, offering both clinical efficacy and health economic advantages.\u003c/p\u003e \u003cp\u003eThe use of ureteral access sheaths remains controversial. While sheaths offer benefits like improved reflux, reduced intrapelvic pressure, and facilitated scope reinsertion[12],potential drawbacks include ureteral wall trauma during placement[13]、ischemic injury from prolonged compression[14], and increased risk of postoperative strictures[15]. A meta-analysis by Huang J et al.[16] demonstrated no significant differences in stone-free rates, intraoperative complications, procedure time, or hospital stay between sheathed and sheathless RIRS, but reported higher postoperative complication rates in the sheathed group. Similarly, a prospective trial by Panthier F[17] showed safe RIRS outcomes without sheaths, with comparable complication rates.In our study, the 6.3Fr non-sheathing group achieved shorter procedure time than the 7.5Fr flexible ureteroscope group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.011), yet complication rates were comparable (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.691). Health economic analysis highlighted cost savings with sheathless RIRS, primarily due to reduced hospital costs. Notably, bladder drainage was critical for maintaining safe intrapelvic pressure in sheathless cases\u0026mdash;we used 8\u0026ndash;10Fr urinary catheters to optimize outflow.\u003c/p\u003e \u003cp\u003eThe magnitude of intrapelvic pressure is closely linked to the duration of surgery and the incidence of infectious complications. Elevated intrapelvic pressure has the potential to cause the backflow of irrigating fluid that contains bacteria and endotoxins into the bloodstream. This, in turn, heightens the risk of postoperative infections, such as fever and sepsis[18\u0026ndash;20]. Moreover, an extended surgical time also increases the likelihood of infectious complications. Prolonged surgeries demand more irrigating fluid, which can further raise intrapelvic pressure[18, 21], Therefore, special attention must be paid to the occurrence of infectious complications after sheathless procedures.\u003c/p\u003e \u003cp\u003eWhen using the HugeMed disposable digital flexible ureteroscope, we opt for gravity irrigation. This method allows for low flow perfusion, ensuring clear visibility and preventing thermal injury while maintaining low intrapelvic pressure. Animal experiments by Samaras A et al. [22] showed that when a 7.5Fr disposable digital flexible ureteroscope is used without an access sheath, the intrapelvic pressure measures 28.25\u0026thinsp;\u0026plusmn;\u0026thinsp;11.2 mmHg, which is within a safe range. Although there are no animal experiments with the finer 6.3Fr disposable flexible ureteroscope, it can be inferred that the intrapelvic pressure will be even lower when using the HugeMed scope. Additionally, when using the laser fiber, which occupies part of the working channel, the reduced water inflow will result in lower intrapelvic pressure[22].In the 6.3Fr non - sheathing group, one patient developed a postoperative fever. The probable causes were identified as the presence of an infectious stone and a relatively long lithotripsy time. Therefore, when using the HugeMed disposable digital flexible ureteroscope, patients should be carefully selected. Antibiotics should be appropriately administered before surgery, and every effort should be made to shorten the operation time.\u003c/p\u003e \u003cp\u003eThe HugeMed disposable digital flexible ureteroscope minimizes patient trauma, reduces pain, and enhances comfort, facilitating faster postoperative recovery. Currently, we primarily treat smaller stones (\u0026lt;\u0026thinsp;1.5 cm), but vigilance against intraoperative/postoperative complications is essential. In cases of intrapelvic hypertension-related complications (e.g., fever, sepsis), management strategies include administering targeted antibiotics, monitoring vital signs, and providing intensive care unit (ICU) support when necessary[23]. Notably, male patients with prostatic hyperplasia often require guidewire assistance to access the ureteral orifice after bladder entry, due to anatomical challenges. In contrast, female patients typically allow direct scope insertion into the ureter without additional aids.\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, only gravity irrigation was used, and there are currently no recommended parameters for perfusion pressure and flow rate. Future research will explore these through in vitro experiments or animal studies. Additionally, the lack of dedicated sheaths suitable for the 6.3Fr scope restricts its application in treating larger stones (\u0026gt;\u0026thinsp;1.5 cm).\u003c/p\u003e \u003cp\u003eIn conclusion, the sheathless technique using the 6.3Fr disposable digital flexible ureteroscope is safe and effective for upper urinary calculi\u0026thinsp;\u0026lt;\u0026thinsp;1.5 cm. Further investigations are warranted to evaluate its role in managing larger stones and other urological conditions.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e \u003c/p\u003e\n\u003cp\u003eAll of the listed authors contributed substantially to the production of this research and manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere was no source of funding for this project.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDoizi S, Kamphuis G, Giusti G, et al. First clinical evaluation of a new single-use flexible ureteroscope (LithoVue\u0026trade;): a European prospective multicentric feasibility study. World J Urol. 2017;35(5):809-18.\u003c/li\u003e\n\u003cli\u003eOfstead CL, Heymann OL, Quick MR, et al. The effectiveness of sterilization for flexible ureteroscopes: A real-world study. American journal of infection control. 2017;45(8):888-95.\u003c/li\u003e\n\u003cli\u003eDavis RB, Farber NJ, Kaplan A, et al. Contemporary practice patterns in the treatment of pediatric stone disease. The Canadian journal of urology. 2018;25(4):9427-32.\u003c/li\u003e\n\u003cli\u003eBagley DH. Flexible ureteropyeloscopy with modular, \u0026quot;disposable\u0026quot; endoscope. Urology. 1987;29(3):296-300.\u003c/li\u003e\n\u003cli\u003eBoylu U, Oommen M, Thomas R, et al. In vitro comparison of a disposable flexible ureteroscope and conventional flexible ureteroscopes. The Journal of urology. 2009;182(5):2347-51.\u003c/li\u003e\n\u003cli\u003eWenbiao L, Guohua Z, Jinchun X, et al. A prospective multicenter randomized controlled clinical trial study of a domestic single-use digital flexible ureteroscope versus a reusable digital flexible ureteroscope for the treatment of upper urinary tract stones. CJU. 2022(05);374-378.\u003c/li\u003e\n\u003cli\u003eLua A, Tan LRL, Panthier F, et al. Optimal deflection techniques for flexible and navigable suction ureteral access sheaths (FANS): a comparative in vitro PEARLS analysis. World J Urol. 2024;42(1):606.\u003c/li\u003e\n\u003cli\u003eChen H, Xiao J, Ge J, et al. Clinical efficacy analysis of tip‑flexible suctioning ureteral access sheath combined with disposable flexible ureteroscope to treat 2-4 cm renal stones. International urology and nephrology. 2024;56(10):3193-9.\u003c/li\u003e\n\u003cli\u003ePatel N, Akhavein A, Hinck B, et al. Tipless Nitinol Stone Baskets: Comparison of Penetration Force, Radial Dilation Force, Opening Dynamics, and Deflection. Urology. 2017;103:256-60.\u003c/li\u003e\n\u003cli\u003eTang X, Wu S, Li Z, et al. Comparison of Thulium Fiber Laser versus Holmium laser in ureteroscopic lithotripsy: a Meta-analysis and systematic review. BMC urology. 2024;24(1):44.\u003c/li\u003e\n\u003cli\u003eMogilevkin Y, Sofer M, Margel D, et al. Predicting an effective ureteral access sheath insertion: a bicenter prospective study. J Endourol. 2014;28(12):1414-7.\u003c/li\u003e\n\u003cli\u003eVanlangendonck R, Landman J. Ureteral access strategies: pro-access sheath. The Urologic clinics of North America. 2004;31(1):71-81.\u003c/li\u003e\n\u003cli\u003eTraxer O, Thomas A. Prospective evaluation and classification of ureteral wall injuries resulting from insertion of a ureteral access sheath during retrograde intrarenal surgery. The Journal of urology. 2013;189(2):580-4.\u003c/li\u003e\n\u003cli\u003eGuzelburc V, Guven S, Boz MY, et al. Intraoperative Evaluation of Ureteral Access Sheath-Related Injuries Using Post-Ureteroscopic Lesion Scale. Journal of laparoendoscopic \u0026amp; advanced surgical techniques Part A. 2016;26(1):23-6.\u003c/li\u003e\n\u003cli\u003eMonga M, Bodie J, Ercole B. Is there a role for small-diameter ureteral access sheaths? Impact on irrigant flow and intrapelvic pressures. Urology. 2004;64(3):439-41; discussion 41-2.\u003c/li\u003e\n\u003cli\u003eHuang J, Zhao Z, AlSmadi JK, et al. Use of the ureteral access sheath during ureteroscopy: A systematic review and meta-analysis. PloS one. 2018;13(2):e0193600.\u003c/li\u003e\n\u003cli\u003ePanthier F, Kwok JL, Tzou DT, et al. What is the definition of stone dust and how does it compare with clinically insignificant residual fragments? A comprehensive review. World J Urol. 2024;42(1):292.\u003c/li\u003e\n\u003cli\u003eTraxer O, Wendt-Nordahl G, Sodha H, et al. Differences in renal stone treatment and outcomes for patients treated either with or without the support of a ureteral access sheath: The Clinical Research Office of the Endourological Society Ureteroscopy Global Study. World J Urol. 2015;33(12):2137-44.\u003c/li\u003e\n\u003cli\u003eMichel MS, Honeck P, Alken P. Conventional high pressure versus newly developed continuous-flow ureterorenoscope: urodynamic pressure evaluation of the renal pelvis and flow capacity. J Endourol. 2008;22(5):1083-5.\u003c/li\u003e\n\u003cli\u003eNoureldin YA, Kallidonis P, Ntasiotis P, et al. The Effect of Irrigation Power and Ureteral Access Sheath Diameter on the Maximal Intra-Pelvic Pressure During Ureteroscopy: In Vivo Experimental Study in a Live Anesthetized Pig. J Endourol. 2019;33(9):725-9.\u003c/li\u003e\n\u003cli\u003eSanta Cruz JAC, Danilovic A, Vicentini FC, et al. Ureteral access sheath. Does it improve the results of flexible ureteroscopy? A narrative review. International braz j urol : official journal of the Brazilian Society of Urology. 2024;50(3):346-58.\u003c/li\u003e\n\u003cli\u003eSamaras A, Tatanis V, Peteinaris A, et al. The Evaluation of Intrarenal Pressure Using a Novel Single-Use Flexible Ureteroscope with Live Intrarenal Pressure Monitoring-An Experimental Study in Porcine Models. Life (Basel, Switzerland). 2024;14(9).\u003c/li\u003e\n\u003cli\u003eHaas CR, Li G, Hyams ES, et al. Delayed Decompression of Obstructing Stones with Urinary Tract Infection is Associated with Increased Odds of Death. The Journal of urology. 2020;204(6):1256-62.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1. Demographic parameters and stone characteristics\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"666\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eFactors\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eValue\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u003cstrong\u003et\u003c/strong\u003e\u003cstrong\u003e（\u003c/strong\u003e\u003cstrong\u003eX\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e\u003cstrong\u003e）\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e6.3\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e(n=35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e7.5\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e(n=35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge (y) Mean \u0026plusmn; SD\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e51.86 \u0026plusmn; 12.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e52.77 \u0026plusmn; 11.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.315\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.754\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e) Mean \u0026plusmn; SD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e22.75 \u0026plusmn; 3.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e22.34 \u0026plusmn; 3.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.503\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.612\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStone size (cm) Mean \u0026plusmn; SD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e1.21 \u0026plusmn; 0.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e1.29 \u0026plusmn; 0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e1.452\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.151\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eN(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGender\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.629\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Femal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e16 (45.71)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e14 (40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Male\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e19 (54.29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e21(60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStone location\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.233\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.629\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;pelvis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e21 (60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e19 (54.29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;ureter \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e14 (40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e16 (45.71)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHydronephrosis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.484\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.785\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNone\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e28 (80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e26 (74.26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMild\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e\u0026nbsp; 6 (17.14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e7 (20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eModerate or severe\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e\u0026nbsp;1 (2.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e2 (5.71)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eurinary infection\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.107\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e0.742\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Yes\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e5 (14.26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e6 (17.14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 244px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;No\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 130px;\"\u003e\n \u003cp\u003e30 (85.71)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 127px;\"\u003e\n \u003cp\u003e29 (82.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 83px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e6.3: 6.3Fr non-sheathing group\u003c/p\u003e\n\u003cp\u003e7.5: 7.5Fr flexible ureteroscope group\u003c/p\u003e\n\u003cp\u003eTable 2. Intraoperative and postoperative data\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"574\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eParameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eValue\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u003cstrong\u003et\u003c/strong\u003e\u003cstrong\u003e（\u003c/strong\u003e\u003cstrong\u003eX\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e\u003cstrong\u003e）\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e6.3\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e(n=35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e7.5\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e(n=35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOperative duration (min)\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMean \u0026plusmn; SD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e50.45 \u0026plusmn; 19.34\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e60.52 \u0026plusmn; 12.47\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e2.589\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.011\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLaser operating time (min)\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMean \u0026plusmn; SD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e22.47 \u0026plusmn; 6.33\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e23.53 \u0026plusmn; 5.66\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e0.741\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.462\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePostoperative hospitalization time (day) Mean \u0026plusmn; SD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e1.37 \u0026plusmn; 0.49\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e1.57 \u0026plusmn; 0.61\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e1.515\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.134\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePostoperative Day 1 hemoglobin drop (g/L) \u0026nbsp;Mean \u0026plusmn; SD\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e5.15 \u0026plusmn; 2.55\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e4.85 \u0026plusmn; 2.37\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e0.515\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.609\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePostoperative Day 1\u0026nbsp;\u003c/strong\u003e \u003cstrong\u003eCreatinine increase \u0026nbsp; \u0026nbsp; (\u0026mu;moI/L ) \u0026nbsp;Mean \u0026plusmn; SD\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e10.16 \u0026plusmn; 5.25\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e8.35 \u0026plusmn; 4.64\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e1.530\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.131\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFirst-stage success rate % (N)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e100% (35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e91.43% (32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e1.393\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.238\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eInitial Stone free rate % (N)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e85.71% (30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e82.86% (29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e0.108\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.743\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFinal stone free rate % (N)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e97.14% (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e94.29% (33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e0.348\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.555\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eN (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eComplications\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e0.158\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.691\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNone\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e32 (91.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e31 (88.57)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Clavien Ⅰ\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e3 (8.57)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e4 (11.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Clavien Ⅱ-Ⅲ\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e0\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStone Composition\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e1.296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e0.255\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Calcium oxalate\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e25 (71.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e29 (82.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Uric acid\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e2 (5.71)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e0 (0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Infection stone\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e5 (14.29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e4 (11.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 193px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp;Mixed\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e3 (8.57)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e2 (5.71)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e6.3: 6.3Fr non-sheathing group\u003c/p\u003e\n\u003cp\u003e7.5: 7.5Fr flexible ureteroscope group\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"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":"world-journal-of-urology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wjur","sideBox":"Learn more about [World Journal of Urology](https://link.springer.com/journal/345)","snPcode":"345","submissionUrl":"https://submission.nature.com/new-submission/345/3","title":"World Journal of Urology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Disposable digital flexible ureteroscope, Ureteral access sheaths, Intrapelvic pressure, Retrograde intrarenal surgery","lastPublishedDoi":"10.21203/rs.3.rs-6246490/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6246490/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo compare the curative effect of 6.3Fr disposable digital flexible ureteroscope and 7.5Fr disposable digital flexible ureteroscope in the treatment of upper urinary tract stones\u0026thinsp;\u0026lt;\u0026thinsp;1.5cm.\u003c/p\u003e\u003ch2\u003eMaterials and Methods\u003c/h2\u003e \u003cp\u003eFrom October 2024 to January 2025, 70 patients with \u0026lt;\u0026thinsp;1.5cm upper urinary tract calculi in our hospital were randomly divided into 2 groups, 35 patients in 6.3Fr non-sheathing group were treated with 6.3Fr HugeMed disposable electronic ureteroscopic laser lithotripsis. In the 7.5Fr flexible ureteroscope group, 35 cases were treated with 7.5Fr common disposable electronic ureteroscope laser lithotripsis. The stone free rate, the success rate of the first stage operation, the operation time and the postoperative hospital stay were compared between the two groups.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe operation time of 6.3Fr non-sheath group was shorter than that of 7.5 flexible ureteroscope group, and the difference was statistically significant (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.011). The success rate of the first stage operation was 100% in the 6.3Fr non-sheath group and 91.43% in the 7.5Fr flexible ureteroscope group, with no statistical significance (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). There were no significant differences in stone free rate, laser working time, hemoglobin decline on the first day after surgery, creatinine increase, postoperative hospitalization days and postoperative complications between the two groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eIn conclusion, the sheathless technique using the 6.3Fr disposable digital flexible ureteroscope is safe and effective for upper urinary calculi\u0026thinsp;\u0026lt;\u0026thinsp;1.5 cm. Further investigations are warranted to evaluate its role in managing larger stones and other urological conditions.\u003c/p\u003e","manuscriptTitle":"Efficacy of 6.3Fr disposable digital flexible ureteroscope versus 7.5Fr disposable digital flexible ureteroscope in the treatment of upper urinary tract stones \u0026lt; 1.5cm: a randomized controlled trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-17 11:58:50","doi":"10.21203/rs.3.rs-6246490/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-10T12:06:50+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-28T08:06:31+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"4878708494686212759362920567987640970","date":"2025-03-28T05:52:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"191625802556695733381352407677287513178","date":"2025-03-28T03:00:09+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-03-27T22:55:13+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-03-19T17:30:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-19T16:47:41+00:00","index":"","fulltext":""},{"type":"submitted","content":"World Journal of Urology","date":"2025-03-17T16:30:39+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"world-journal-of-urology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wjur","sideBox":"Learn more about [World Journal of Urology](https://link.springer.com/journal/345)","snPcode":"345","submissionUrl":"https://submission.nature.com/new-submission/345/3","title":"World Journal of Urology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"84a54faa-6118-4a49-a6cf-045d17dc6d0f","owner":[],"postedDate":"April 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-06-30T16:01:38+00:00","versionOfRecord":{"articleIdentity":"rs-6246490","link":"https://doi.org/10.1007/s00345-025-05751-w","journal":{"identity":"world-journal-of-urology","isVorOnly":false,"title":"World Journal of Urology"},"publishedOn":"2025-06-23 15:57:09","publishedOnDateReadable":"June 23rd, 2025"},"versionCreatedAt":"2025-04-17 11:58:50","video":"","vorDoi":"10.1007/s00345-025-05751-w","vorDoiUrl":"https://doi.org/10.1007/s00345-025-05751-w","workflowStages":[]},"version":"v1","identity":"rs-6246490","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6246490","identity":"rs-6246490","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}