Is Ambulatory Flexible Ureteroscopic Lithotripsy Safe and Feasible? Evidence from a Propensity Score–Matched Cohort

Is Ambulatory Flexible Ureteroscopic Lithotripsy Safe and Feasible? Evidence from a Propensity Score–Matched Cohort | 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 Is Ambulatory Flexible Ureteroscopic Lithotripsy Safe and Feasible? Evidence from a Propensity Score–Matched Cohort Cong Tian, Jie Gu, Lianming Wang, Liulin Xiong, Bo Yang, Hao Hu, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8587174/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 06 Apr, 2026 Read the published version in BMC Urology → Version 1 posted 15 You are reading this latest preprint version Abstract Objective To evaluate the safety, efficacy, and health economic value of flexible ureteroscopic lithotripsy (fURS) for upper urinary tract stones in ambulatory surgery compared to traditional inpatient management. Methods A retrospective cohort study analyzed 174 fURS cases performed by a single surgeon between January and December 2024. Patients were divided into ambulatory and inpatient groups. Propensity score matching (PSM, 1:1 ratio) was applied to balance baseline differences. Demographic data, perioperative parameters, and outcomes including stone-free rate (SFR), complication rates (Clavien-Dindo classification), hospitalization duration, and costs were analyzed. Results A total of 174 patients with upper urinary tract stones were included. Pre-matching analysis revealed that the inpatient group had significantly older age (58.55 ± 12.52 vs. 50.14 ± 12.79 years, P < 0.001), larger cumulative stone diameter (1.67 ± 0.74 vs. 1.34 ± 0.57 cm, P = 0.001), and longer operative time (53.09 ± 26.64 vs. 41.30 ± 21.45 min, P = 0.002). No significant differences were observed in postoperative complications (2.33% vs. 1.14%, P = 0.491) or SFR (86.05% vs. 89.66%, P = 0.502). The ambulatory group demonstrated a 74.6% reduction in hospitalization duration (1.09 ± 0.29 vs. 4.29 ± 1.14 days, P < 0.001) and lower total costs (27,075.41 ± 4,112.93 vs. 29,240.94 ± 3,856.12 RMB, P < 0.001). Post-PSM analysis confirmed comparable baseline characteristics, with the ambulatory group maintaining shorter hospitalization (1.12 ± 0.31 vs. 4.05 ± 1.08 days, P < 0.001), while cost differences became non-significant (27,532 ± 3,982 vs. 28,916 ± 4,205 RMB, P = 0.106). Conclusion Ambulatory fURS represents a safe and effective treatment option for selected patients with upper urinary tract stones. When performed under standardized perioperative protocols and appropriate patient selection, this model can substantially reduce hospitalization duration without compromising surgical outcomes or patient safety, thereby supporting more efficient utilization of healthcare resources. Ambulatory surgery Flexible ureteroscopic lithotripsy Upper urinary tract stones Efficacy Safety Introduction Upper urinary tract stones (renal and ureteral stones) are highly prevalent worldwide, with an increasing incidence in recent years. 1 These stones not only cause severe pain, hematuria, and urinary tract obstruction but also lead to renal dysfunction, significantly compromising patients' quality of life. With advancements in minimally invasive techniques, flexible ureteroscopic lithotripsy (fURS) has emerged as a mainstream treatment for upper urinary tract stones due to its minimal invasiveness and rapid recovery. 2 , 3 However, the high medical resource utilization associated with traditional inpatient fURS limits its clinical efficiency. The ambulatory surgery model, characterized by "same-day admission, surgery, and discharge within 24 hours," was first introduced in 2001 and has been widely applied in procedures such as laparoscopic cholecystectomy, inguinal hernia repair, and varicose vein. This model significantly reduces hospitalization duration and optimizes healthcare resource allocation. Previous studies have reported the feasibility and safety of urological stone-related procedures in ambulatory setting. 4 Nevertheless, the widespread adoption of this model faces systemic challenges. For fURS, key concerns include preoperative control of urinary tract infections, intraoperative management of elevated renal pelvic pressure, early identification and management of postoperative complications (particularly infections), feasibility of post-discharge pain management, and the risk of short-term readmission. 3 , 5 To date, there is a lack of well-controlled comparative studies evaluating whether ambulatory fURS can achieve equivalent safety outcomes without increasing short-term readmissions or complications. This study retrospectively analyzed clinical data from patients undergoing fURS for upper urinary tract stones in ambulatory surgery setting, aiming to evaluate stone-free rates, postoperative complication rates, hospitalization costs, and other outcomes. Propensity score matching (PSM) analysis was employed to balance baseline characteristics between groups. The findings will provide evidence-based support for standardizing the ambulatory surgery model in urological practice while offering theoretical insights into optimizing healthcare resource allocation and improving patient treatment experiences. Methods 1. Study Design and Participants This retrospective study included patients who fURS for upper ureteral or renal stones performed by a single senior urologist (surgical experience > 10 years) between January 2024 and December 2024. The inclusion criteria were as follows: (1) Age 18–75 years; (2) Preoperative CT-confirmed renal or upper ureteral stones; (3) Complete follow-up data. The exclusion criteria included the following: (1)Severe urinary tract infection, coagulation disorders, or pregnancy; (2)Bilateral stones requiring simultaneous surgery; (3) Conversion to percutaneous nephrolithotomy (PCNL). The follow-up period began at admission and ended at 1 month postoperatively, with follow-up conducted via outpatient visits or telephone interviews. 2. Data Collection Perioperative data included: Demographics and baseline characteristics: Age, sex, Body Mass Index (BMI), American Society of Anesthesiologists Physical Status Classification System (ASA) classification, and medical history (hypertension, diabetes, coronary artery disease, etc.);Surgical details: Cumulative stone diameter (defined as the sum of the maximum diameters of all stones in coronal/axial/sagittal planes), stone type, stone location, preoperative nephrostomy/stent placement, and operative time; Outcome measures: Postoperative vital signs, fever, blood transfusion, special medication use, reoperation, ICU admission, complications, hospital stay duration, hospitalization costs, and stone-free rate (assessed via abdominal X-ray within 24 hours postoperatively; residual fragments > 2 mm were considered significant).Sepsis was diagnosed using the Sepsis-3.0 criteria. 6 Patients were stratified into two groups based on postoperative complications. Fever ≤ 38°C without other complications was classified as "no complication". 7 3. Perioperative Management 3.1 Preoperative Preparation All patients underwent urinalysis and urine culture during outpatient visits. Those with positive cultures received culture-directed antibiotics until two consecutive negative results were achieved. A single dose of prophylactic antibiotics (second-generation cephalosporin/levofloxacin/etimicin) was administered intravenously 30 minutes preoperatively. 3.2 Surgical Procedure Under laryngeal mask general anesthesia: Cystoscopy was performed, and a hydrophilic guidewire (Brad®) was placed into the affected ureteric orifice. For upper ureteral stones, pneumatic lithotripsy was used to retropulse stones into the renal pelvis; for renal stones, the guidewire was advanced directly into the renal pelvis. A ureteral access sheath (Flexor® 12/14F, Cook Medical) was placed over the guidewire. Stones were fragmented using a flexible ureteroscope with holmium laser (Power Suite 60W Plus, Lumenis; settings: 0.8–1.2 J, 10–20 Hz). Larger fragments were retrieved with a nitinol basket (NGage®, Cook Medical). A 6Fr double-J stent (Bard®) was routinely placed. Postoperative care: Inpatients: Urinary catheter retained postoperatively; removed after normal KUB findings on postoperative day 1. Ambulatory patients: Single catheterization postoperatively; discharged after confirming normal KUB and blood tests. The double-J stent was removed via outpatient cystoscopy at 14 days. 3.3 Discharge Criteria Ambulatory surgery group: Normal voiding function post-catheter removal (no dysuria or gross hematuria); Stable vital signs (afebrile, no chills); Normal mobility (independent ambulation); Normal neurological status (no headache/dizziness); Normal digestive function (no nausea/vomiting); Normal postoperative KUB. Inpatient group: Standard discharge criteria applied, with additional emphasis on: Daily fluid intake (2000–2500 mL); Self-monitoring (urinary output, temperature, pain score). 4. Statistical Analysis Data were analyzed using SPSS 26.0 and R 4.4.2. Continuous variables were expressed as mean ± SD or median [Interquartile Range]; categorical variables as frequencies (%). Intergroup comparisons used independent t-tests/Mann-Whitney U tests (continuous) or chi-square/Fisher’s exact tests (categorical). Propensity score matching (PSM, 1:1 ratio, caliper = 0.1) balanced baseline differences. P < 0.05 was considered statistically significant. Results 1. Baseline Characteristics A total of 174 patients with upper urinary tract stones were included, comprising 88 in the ambulatory surgery group and 86 in the inpatient group. Key demographic and clinical data are summarized in Table 1 . Inpatients were significantly older than ambulatory patients (58.55 ± 12.52 vs. 50.14 ± 12.79 years, P < 0.001), with no sex disparity (P = 0.923).ASA classification (P = 0.108) and BMI (26.16 ± 3.57 vs. 25.54 ± 3.73, P = 0.267) were comparable between groups. Inpatients had larger cumulative stone diameters (1.67 ± 0.74 vs. 1.34 ± 0.57 cm, P = 0.001) and longer operative times (53.09 ± 26.64 vs. 41.30 ± 21.45 min, P = 0.002). No differences were observed in preoperative nephrostomy (P = 0.254) or double-J stent placement rates (P = 0.632). Hospitalization costs were higher for inpatients (¥29,240.94 ± 3,856.12 vs. ¥27,075.41 ± 4,112.93, P < 0.001). Ambulatory patients had significantly shorter hospital stays (1.09 ± 0.29 vs. 4.29 ± 1.14 days, P < 0.001). Stone-free rates (82.95% vs. 80.23%, P = 0.789) and complication rates (2.33% vs. 1.14%, P = 0.491) were similar, with all complications being Clavien-Dindo grade I. No difference was found in 30-day readmission rates (P = 0.506). One ambulatory patient (an elderly male with benign prostatic hyperplasia) was readmitted for febrile urinary retention and discharged after antibiotic therapy. Table 1 Clinical characteristics of patients Inpatient surgery ambulatory surgery Overall P (N = 86) (N = 88) (N = 174) Age < 0.001 * Mean (SD) 58.55 (12.52) 50.14 (12.79) 54.29 (13.30) Sex 0.923 Female 25 (29.07%) 25 (28.41%) 50 (28.74%) Male 61 (70.93%) 63 (71.59%) 124 (71.26%) ASA 0.108 Grade I 6 (6.98%) 14 (15.91%) 20 (11.49%) Grade II 65 (75.58%) 65 (73.86%) 130 (74.71%) Grade III 13 (15.12%) 9 (10.3%) 22 (12.64%) Grade IV 2 (2.32%) 0 (0.00%) 2 (1.16%) BMI 0.267 Mean (SD) 26.16 (3.57) 25.54 (3.73) 25.85 (3.65) Stone type 0.03 * Single 48 (55.81%) 63 (71.59%) 111 (63.79%) Multiple 38 (44.19%) 25 (28.41%) 63 (36.21%) Cumulative stone diameter 0.001 * Mean (SD) 1.67 (0.74) 1.34 (0.57) 1.51 (0.68) Time of surgery 0.002 * Mean (SD) 53.09 (26.64) 41.30 (21.45) 47.13 (24.80) Preoperative nephrostomy 0.254 No 86 (100.00%) 86 (97.73%) 172 (98.85%) Yes 0 (0.00%) 2 (2.27%) 2 (1.15%) Preoperative stent 0.632 No 71 (82.56%) 75 (85.22%) 146 (83.91%) Yes 15 (17.44%) 13 (14.78%) 28 (16.09%) Hospitalization costs < 0.001 * Mean (SD) 29240.94 (3856.12) 27075.41 (4112.93) 28145.73 (4122.12) Length of stay (day) < 0.001 * Mean (SD) 4.29 (1.14) 1.09 (0.29) 2.67 (1.80) SFR 0.789 80.23% 82.95% 81.61% Readmission 0.506 No 86 (100.00%) 87 (98.86%) 173 (99.43%) Yes 0 (0.00%) 1 (1.14%) 1 (0.57%) Postoperative complication 0.491 None 84 (97.67%) 87 (98.86%) 171 (98.28%) Grade I 2 (2.33%) 1 (1.14%) 3 (1.72%) Grade II 0 (0.00%) 0 (0.00%) 0 (0.00%) Grade III Grade IV 0 (0.00%) 0 (0.00%) 0 (0.00%) 0 (0.00%) 0 (0.00%) 0 (0.00%) *P < 0.05 indicating statistical significance. Table 1 : Clinical characteristics of total patients 2. Subgroup Analysis of Ambulatory Patients Eight ambulatory patients required overnight observation (Table 2 ). These patients were older (64.1 ± 13.2 vs. 48.7 ± 11.5 years, P = 0.001), predominantly female (P < 0.001), and had more comorbidities (P < 0.001). Table 2 Clinical characteristics of Ambulatory patients Normal group Special group Overall P (N = 80) (N = 8) (N = 88) Age 0.001 * Mean (SD) 48.74 (11.5) 64.13 (13.24) 50.14 (12.79) Sex < 0.001 * Female 18 (22.50%) 7 (87.50%) 25 (28.41%) Male 62 (77.50%) 1 (12.50%) 63 (71.59%) ASA < 0.001 * Grade I 14 (17.50%) 0 (0.00%) 14 (15.91%) Grade II 61 (76.25%) 4 (50.00%) 65 (73.86%) Grade III 5 (6.25%) 4 (50.00%) 9 (10.23%) BMI 0.160 Mean (SD) 25.36 (3.62) 27.31 (4.58) 25.54 (3.73) Stone type 0.937 Single 57 (71.25%) 6 (75.00%) 63 (71.59%) Multiple 23 (28.75%) 2 (25.00%) 24 (28.41%) Cumulative stone diameter 0.622 Mean (SD) 1.33 (0.57) 1.44 (0.59) 1.34 (0.57) Time of surgery 0.564 Mean (SD) 40.88 (19.53) 45.50 (37.29) 41.30 (21.45) Preoperative nephrostomy 0.175 No 79 (98.75%) 7 (87.50%) 86 (97.73%) Yes 1 (1.25%) 1 (12.50%) 2 (2.27%) Preoperative stent 0.092 No 70 (87.50%) 5 (62.50%) 75 (85.23%) Yes 10 (12.50%) 3 (37.50%) 13 (14.77%) Hospitalization costs 0.552 Mean (SD) 26992.21 (4239.92) 27907.38 (2547.84) 27075.41 (4112.93) SFR 1.00 0 82.50% 87.50% 83.00% Readmission 0.909 0 79 (98.75%) 8 (100.00%) 87 (98.86%) 1 1 (1.25%) 0 (0.00%) 1 (1.14%) Postoperative complication 0.909 None 79 (98.75%) 8 (100.00%) 87 (98.86%) Grade I 1 (1.25%) 0 (0.00%) 1 (1.14%) *P < 0.05 indicating statistical significance. Table 2 : Clinical characteristics of Ambulatory patients 3. Propensity Score Matching (PSM) Analysis After 1:1 PSM (matched for age, sex, cumulative stone diameter, and ASA grade; caliper = 0.1), 57 matched pairs were analyzed (Table 3 ).Baseline characteristics were balanced post-matching (all P > 0.05). Ambulatory surgery was associated with shorter hospitalization (1.14 ± 0.35 vs. 4.16 ± 1.10 days, P < 0.001), while costs and stone-free rates showed no significant differences. Table 3 Clinical characteristics of patients after PSM Inpatient surgery ambulatory surgery Overall P (N = 57) (N = 57) (N = 114) Age 0.627 Mean (SD) 54.53 (11.46) 54.58 (12.30) 54.55 (11.85) Sex 0.677 Female 17 (29.82%) 15 (26.32%) 32 (28.07%) Male 40 (70.18%) 42 (73.68%) 82 (71.93%) ASA 0.640 Grade I 5 (8.77%) 2 (3.51%) 7 (6.14%) Grade II 46 (80.70%) 49 (85.96%) 95 (83.33%) Grade III 6 (10.53%) 6 (10.53%) 12 (10.53%) BMI 0.464 Mean (SD) 25.86 (3.81) 25.79 (3.78) 25.83 (3.78) Stone type 0.695 Single 36 (63.2%) 38 (66.7%) 74 (64.9%) Multiple 21 (36.8%) 19 (31.6%) 39 (34.2%) Cumulative stone diameter 0.226 Mean (SD) 1.56 (0.74) 1.50 (0.58) 1.53 (0.66) Time of surgery 0.014 Mean (SD) 51.68 (26.94) 43.07 (21.89) 47.38 (24.82) Preoperative nephrostomy 0.248 No 57 (100.00%) 55 (96.49%) 112 (98.25%) Yes 0 (0.00%) 2 (3.51%) 2 (1.75%) Preoperative stent 1.000 No 46 (80.70%) 46 (80.70%) 92 (80.70) Yes 11 (19.30%) 11 (19.30%) 22 (19.30%) cost 0.604 Mean (SD) 28682.23 (3843.68) 27379.11 (3600.24) 28030.67 (3764.75) Length of stay (day) < 0.001 Mean (SD) 4.16 (1.10) 1.14 (0.35) 2.65 (1.72) SFR 0.812 82.46% 78.95% 80.70% Readmission 0.500 0 57 (100.00%) 56 (98.25%) 113 (99.12%) 1 0 (0.00%) 1 (1.75%) 1 (0.88%) Postoperative complication 0.752 None 56 (98.25%) 56 (98.25%) 112 (98.25%) Grade I 1 (1.75%) 1 (1.75%) 2 (1.75%) *P < 0.05 indicating statistical significance. Table 3 : Clinical characteristics of patients after PSM Discussion This retrospective propensity score–matched study systematically compared the safety, effectiveness, and health system impact of ambulatory versus inpatient flexible ureteroscopic lithotripsy (fURS) for upper urinary tract stones. Our findings demonstrate that, in carefully selected patients, ambulatory fURS achieves comparable stone-free rates and postoperative safety outcomes to conventional inpatient management, while significantly reducing hospitalization duration. These results support the feasibility of expanding ambulatory fURS within modern urological practice. After adjustment for baseline differences using propensity score matching, no significant differences were observed between groups in terms of postoperative complications, stone-free rates, or 30-day readmission rates. Importantly, all recorded complications were minor (Clavien–Dindo grade I), and no severe infectious or surgical adverse events occurred. These findings are consistent with previous reports indicating that fURS, when performed under standardized protocols, is associated with low morbidity. However, compared with earlier studies reporting complication rates ranging from 0.3% to over 30% 8 , the notably low complication rate in our cohort highlights the importance of strict perioperative management and patient selection. Several factors may explain the favorable safety profile observed in the ambulatory group. First, rigorous preoperative infection control was implemented, including routine urine culture screening and culture-directed antibiotic therapy until confirmed negativity. Second, standardized intraoperative techniques—such as routine use of ureteral access sheaths, controlled laser settings, and efforts to minimize intrarenal pressure—likely reduced the risk of bacterial translocation and postoperative infection. Third, clearly defined discharge criteria and routine placement of double-J stents provided additional postoperative safety, enabling early discharge without increasing complication or readmission rates. Although the overall outcomes were comparable, subgroup analysis within the ambulatory cohort revealed that a small proportion of patients required overnight observation. These patients were generally older, predominantly female, and had higher ASA classifications, suggesting a greater burden of comorbidities. This finding underscores the critical role of patient selection in ambulatory fURS. While most patients can be safely discharged within 24 hours, elderly individuals and those with multiple comorbid conditions may benefit from extended postoperative monitoring, even when managed within an ambulatory framework. Such risk stratification may help optimize safety while maintaining efficiency. From a health-economic perspective, ambulatory fURS was associated with significantly shorter hospital stays both before and after matching. Although total hospitalization costs were lower in the ambulatory group before matching, this difference was no longer statistically significant after PSM adjustment. This finding suggests that the primary economic advantage of ambulatory fURS may not lie in direct cost reduction but rather in improved healthcare resource utilization. Shorter hospital stays can enhance bed turnover efficiency, reduce inpatient occupancy, and increase overall system capacity—an increasingly important consideration in high-volume tertiary centers. This study has several limitations. Its retrospective single-center design introduces the possibility of selection bias, despite the use of propensity score matching. Additionally, all procedures were performed by a single experienced surgeon, which may limit the generalizability of the results to lower-volume or less-experienced centers. Long-term outcomes, including stone recurrence and patient-reported measures such as postoperative discomfort and satisfaction, were not assessed. Furthermore, indirect costs and broader societal economic impacts were not included in the cost analysis. Future multicenter prospective studies or randomized controlled trials are warranted to validate these findings and refine patient selection criteria. In conclusion, ambulatory fURS represents a safe and effective treatment option for selected patients with upper urinary tract stones. When performed under standardized perioperative protocols and appropriate patient selection, this model can substantially reduce hospitalization duration without compromising surgical outcomes or patient safety, thereby supporting more efficient utilization of healthcare resources. Conclusion Ambulatory fURS represents a safe and effective treatment option for selected patients with upper urinary tract stones. When performed under standardized perioperative protocols and appropriate patient selection, this model can substantially reduce hospitalization duration without compromising surgical outcomes or patient safety, thereby supporting more efficient utilization of healthcare resources. Abbreviations ASA American Society of Anesthesiologists Physical Status Classification System BMI Body Mass Index fURS flexible ureteroscopic lithotripsy PCNL percutaneous nephrolithotomy PSM Propensity score matching SFR stone-free rate Declarations Ethics approval and consent to participate This study was conducted in accordance with the Declaration of Helsinki (revised in 2013). The study was approved by the ethics board of the Peking University People’s Hospital Review Board (2024PHB170-001). Informed consent forms were signed by all patients. Consent for publication Not Applicable Clinical trial number: Not applicable. Availability of data and materials The data that support the findings of this study are available from [Peking University People's Hospital] but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of [Peking University People's Hospital]. Competing Interests Cong Tian and Jie Gu declare conflict of interest that they contributed equally to this work. Remaining all authors (Lianming Wang, Liulin Xiong, Bo Yang, Hao Hu, Tao Xu, Junjun Xu, Jun Liu) declare no conflict of interest. Funding This project was supported by Peking University People’s Hospital research and development funds (RDL2024-21, RDE2025-09, and RDE2023-11). Authors' contributions Cong Tian: Project development, Data analysis, Manuscript writing Jie Gu: Project development, Data analysis, Manuscript writing Lianming Wang: Data analysis Liulin Xiong: Data collection Bo Yang: Data collection Hao Hu: Data collection Tao Xu: Data collection Junjun Xu: Data collection Jun Liu: Project development, Manuscript editing Acknowledgement None References Tan S, Yuan D, Su H, et al. Prevalence of urolithiasis in China: a systematic review and meta-analysis. BJU Int. 2024;133(1):34–43. Geraghty RM, Davis NF, Tzelves L, et al. Best Practice in Interventional Management of Urolithiasis: An Update from the European Association of Urology Guidelines Panel for Urolithiasis 2022. Eur Urol focus. 2023;9(1):199–208. He M, Dong Y, Cai W, et al. Recent advances in the treatment of renal stones using flexible ureteroscopys. Int J Surg (London England). 2024;110(7):4320–8. Shabana W, Oquendo F, Hodhod A, et al. Miniaturized Ambulatory Percutaneous Nephrolithotomy Versus Flexible Ureteroscopy in the Management of Lower Calyceal Renal Stones 10–20 mm: A Propensity Score Matching Analysis. Urology. 2021;156:65–70. John J, Wisniewski P, Fieggen G, et al. Intrarenal Pressure in Retrograde Intrarenal Surgery: A Narrative Review. Urology. 2025;195:201–9. Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801–10. Singh AK, Shukla PK, Khan SW, et al. Using the Modified Clavien Grading System to Classify Complications of Percutaneous Nephrolithotomy. Curr Urol. 2018;11(2):79–84. Grosso AA, Sessa F, Campi R, et al. Intraoperative and postoperative surgical complications after ureteroscopy, retrograde intrarenal surgery, and percutaneous nephrolithotomy: a systematic review. Minerva Urol Nephrol. 2021;73(3):309–32. Additional Declarations Competing interest reported. Cong Tian and Jie Gu declare conflict of interest that they contributed equally to this work. Remaining all authors (Lianming Wang, Liulin Xiong, Bo Yang, Hao Hu, Tao Xu, Junjun Xu, Jun Liu) declare no conflict of interest. Cite Share Download PDF Status: Published Journal Publication published 06 Apr, 2026 Read the published version in BMC Urology → Version 1 posted Editorial decision: Revision requested 17 Feb, 2026 Reviews received at journal 14 Feb, 2026 Reviews received at journal 14 Feb, 2026 Reviewers agreed at journal 13 Feb, 2026 Reviews received at journal 13 Feb, 2026 Reviews received at journal 12 Feb, 2026 Reviewers agreed at journal 11 Feb, 2026 Reviewers agreed at journal 08 Feb, 2026 Reviewers agreed at journal 08 Feb, 2026 Reviewers agreed at journal 08 Feb, 2026 Reviewers invited by journal 08 Feb, 2026 Editor invited by journal 22 Jan, 2026 Editor assigned by journal 19 Jan, 2026 Submission checks completed at journal 19 Jan, 2026 First submitted to journal 12 Jan, 2026 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8587174","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":589413095,"identity":"e210d948-1c25-4a1c-9809-84e2270aec9b","order_by":0,"name":"Cong Tian","email":"","orcid":"","institution":"Peking University People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Cong","middleName":"","lastName":"Tian","suffix":""},{"id":589413097,"identity":"c693ab30-3b3e-48f5-b01e-b974831e854d","order_by":1,"name":"Jie Gu","email":"","orcid":"","institution":"Peking University People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Jie","middleName":"","lastName":"Gu","suffix":""},{"id":589413098,"identity":"44b62d08-26a8-4ffd-ab95-4408f67a63ab","order_by":2,"name":"Lianming Wang","email":"","orcid":"","institution":"Qingzhou City People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Lianming","middleName":"","lastName":"Wang","suffix":""},{"id":589413099,"identity":"834916bd-1909-40fd-8db5-1ff643c96afd","order_by":3,"name":"Liulin Xiong","email":"","orcid":"","institution":"Peking University People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Liulin","middleName":"","lastName":"Xiong","suffix":""},{"id":589413100,"identity":"1423bc44-06e2-4d44-aecc-ccb01f97897d","order_by":4,"name":"Bo Yang","email":"","orcid":"","institution":"Peking University People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"","lastName":"Yang","suffix":""},{"id":589413101,"identity":"2b1481e4-52a8-4fad-bdb4-18cd3443033c","order_by":5,"name":"Hao Hu","email":"","orcid":"","institution":"Peking University People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Hu","suffix":""},{"id":589413102,"identity":"9ac8d269-07d7-4e4d-a051-de301b898df9","order_by":6,"name":"Tao Xu","email":"","orcid":"","institution":"Peking University People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tao","middleName":"","lastName":"Xu","suffix":""},{"id":589413103,"identity":"f8edf376-2aaf-490e-b039-e7a789ecb814","order_by":7,"name":"Junjun Xu","email":"","orcid":"","institution":"Peking University People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Junjun","middleName":"","lastName":"Xu","suffix":""},{"id":589413104,"identity":"f3840114-f97a-4f6c-adc8-ea09351fc224","order_by":8,"name":"Jun Liu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuElEQVRIiWNgGAWjYBACAwYGxgMJDGwMDOyNjQ8/EKmFAaKF53CzsQTRWsAsifQ2AR5itJiLnTE48LCNL3G75MM2BgkGOzndBgJaLGfnGBxIbGNL3Dk7se1BAUOysdkBQg67DdWy4XZiu4EEw4HEbcRruXmwTYKHNC03GInWklZwIOEcm/GGM4nAQDYgyi/JGx/+KDsmu+H48YcPP1TYyRHUAgXHYCYQpxwEaohXOgpGwSgYBSMPAACzRUm0ayb/hQAAAABJRU5ErkJggg==","orcid":"","institution":"Peking University People's Hospital","correspondingAuthor":true,"prefix":"","firstName":"Jun","middleName":"","lastName":"Liu","suffix":""}],"badges":[],"createdAt":"2026-01-13 04:38:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8587174/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8587174/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12894-026-02129-x","type":"published","date":"2026-04-06T15:58:37+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":106809955,"identity":"5ca39c4e-8401-43c9-832f-8d671df9cf2f","added_by":"auto","created_at":"2026-04-13 16:13:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1236829,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8587174/v1/245ceea8-c5a0-4106-9517-a7c6fc1cd887.pdf"}],"financialInterests":"Competing interest reported. Cong Tian and Jie Gu declare conflict of interest that they contributed equally to this work. Remaining all authors (Lianming Wang, Liulin Xiong, Bo Yang, Hao Hu, Tao Xu, Junjun Xu, Jun Liu) declare no conflict of interest.","formattedTitle":"Is Ambulatory Flexible Ureteroscopic Lithotripsy Safe and Feasible? Evidence from a Propensity Score–Matched Cohort","fulltext":[{"header":"Introduction","content":"\u003cp\u003eUpper urinary tract stones (renal and ureteral stones) are highly prevalent worldwide, with an increasing incidence in recent years. \u003csup\u003e1\u003c/sup\u003e These stones not only cause severe pain, hematuria, and urinary tract obstruction but also lead to renal dysfunction, significantly compromising patients' quality of life. With advancements in minimally invasive techniques, flexible ureteroscopic lithotripsy (fURS) has emerged as a mainstream treatment for upper urinary tract stones due to its minimal invasiveness and rapid recovery.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e However, the high medical resource utilization associated with traditional inpatient fURS limits its clinical efficiency.\u003c/p\u003e \u003cp\u003eThe ambulatory surgery model, characterized by \"same-day admission, surgery, and discharge within 24 hours,\" was first introduced in 2001 and has been widely applied in procedures such as laparoscopic cholecystectomy, inguinal hernia repair, and varicose vein. This model significantly reduces hospitalization duration and optimizes healthcare resource allocation. Previous studies have reported the feasibility and safety of urological stone-related procedures in ambulatory setting.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e Nevertheless, the widespread adoption of this model faces systemic challenges. For fURS, key concerns include preoperative control of urinary tract infections, intraoperative management of elevated renal pelvic pressure, early identification and management of postoperative complications (particularly infections), feasibility of post-discharge pain management, and the risk of short-term readmission.\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eTo date, there is a lack of well-controlled comparative studies evaluating whether ambulatory fURS can achieve equivalent safety outcomes without increasing short-term readmissions or complications. This study retrospectively analyzed clinical data from patients undergoing fURS for upper urinary tract stones in ambulatory surgery setting, aiming to evaluate stone-free rates, postoperative complication rates, hospitalization costs, and other outcomes. Propensity score matching (PSM) analysis was employed to balance baseline characteristics between groups. The findings will provide evidence-based support for standardizing the ambulatory surgery model in urological practice while offering theoretical insights into optimizing healthcare resource allocation and improving patient treatment experiences.\u003c/p\u003e \n\n \n\n\n\n \n\n"},{"header":"Methods","content":"\u003ch3\u003e1. Study Design and Participants\u003c/h3\u003e\u003cp\u003eThis retrospective study included patients who fURS for upper ureteral or renal stones performed by a single senior urologist (surgical experience \u0026gt; 10 years) between January 2024 and December 2024. The inclusion criteria were as follows: (1) Age 18–75 years;\u003c/p\u003e\u003cp\u003e(2) Preoperative CT-confirmed renal or upper ureteral stones; (3) Complete follow-up data. The exclusion criteria included the following: (1)Severe urinary tract infection, coagulation disorders, or pregnancy; (2)Bilateral stones requiring simultaneous surgery;\u003c/p\u003e\u003cp\u003e(3) Conversion to percutaneous nephrolithotomy (PCNL). The follow-up period began at admission and ended at 1 month postoperatively, with follow-up conducted via outpatient visits or telephone interviews.\u003c/p\u003e\u003ch3\u003e2. Data Collection\u003c/h3\u003e\u003cp\u003ePerioperative data included: Demographics and baseline characteristics: Age, sex, Body Mass Index (BMI), American Society of Anesthesiologists Physical Status Classification System (ASA) classification, and medical history (hypertension, diabetes, coronary artery disease, etc.);Surgical details: Cumulative stone diameter (defined as the sum of the maximum diameters of all stones in coronal/axial/sagittal planes), stone type, stone location, preoperative nephrostomy/stent placement, and operative time; Outcome measures: Postoperative vital signs, fever, blood transfusion, special medication use, reoperation, ICU admission, complications, hospital stay duration, hospitalization costs, and stone-free rate (assessed via abdominal X-ray within 24 hours postoperatively; residual fragments \u0026gt; 2 mm were considered significant).Sepsis was diagnosed using the Sepsis-3.0 criteria.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e Patients were stratified into two groups based on postoperative complications. Fever ≤ 38°C without other complications was classified as \"no complication\". \u003csup\u003e7\u003c/sup\u003e\u003c/p\u003e\u003ch3\u003e3. Perioperative Management\u003c/h3\u003e\u003ch2\u003e3.1 Preoperative Preparation\u003c/h2\u003e\u003cp\u003eAll patients underwent urinalysis and urine culture during outpatient visits. Those with positive cultures received culture-directed antibiotics until two consecutive negative results were achieved. A single dose of prophylactic antibiotics (second-generation cephalosporin/levofloxacin/etimicin) was administered intravenously 30 minutes preoperatively.\u003c/p\u003e\u003ch2\u003e3.2 Surgical Procedure\u003c/h2\u003e\u003cp\u003eUnder laryngeal mask general anesthesia: Cystoscopy was performed, and a hydrophilic guidewire (Brad®) was placed into the affected ureteric orifice. For upper ureteral stones, pneumatic lithotripsy was used to retropulse stones into the renal pelvis; for renal stones, the guidewire was advanced directly into the renal pelvis. A ureteral access sheath (Flexor® 12/14F, Cook Medical) was placed over the guidewire. Stones were fragmented using a flexible ureteroscope with holmium laser (Power Suite 60W Plus, Lumenis; settings: 0.8–1.2 J, 10–20 Hz). Larger fragments were retrieved with a nitinol basket (NGage®, Cook Medical). A 6Fr double-J stent (Bard®) was routinely placed. Postoperative care: Inpatients: Urinary catheter retained postoperatively; removed after normal KUB findings on postoperative day 1. Ambulatory patients: Single catheterization postoperatively; discharged after confirming normal KUB and blood tests. The double-J stent was removed via outpatient cystoscopy at 14 days.\u003c/p\u003e\u003ch2\u003e3.3 Discharge Criteria\u003c/h2\u003e\u003cp\u003eAmbulatory surgery group: Normal voiding function post-catheter removal (no dysuria or gross hematuria); Stable vital signs (afebrile, no chills); Normal mobility (independent ambulation); Normal neurological status (no headache/dizziness); Normal digestive function (no nausea/vomiting); Normal postoperative KUB.\u003c/p\u003e\u003cp\u003eInpatient group: Standard discharge criteria applied, with additional emphasis on:\u003c/p\u003e\u003cp\u003eDaily fluid intake (2000–2500 mL); Self-monitoring (urinary output, temperature, pain score).\u003c/p\u003e\u003ch3\u003e4. Statistical Analysis\u003c/h3\u003e\u003cp\u003eData were analyzed using SPSS 26.0 and R 4.4.2. Continuous variables were expressed as mean ± SD or median [Interquartile Range]; categorical variables as frequencies (%). Intergroup comparisons used independent t-tests/Mann-Whitney U tests (continuous) or chi-square/Fisher’s exact tests (categorical). Propensity score matching (PSM, 1:1 ratio, caliper = 0.1) balanced baseline differences. P \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\n\u003ch3\u003e1. Baseline Characteristics\u003c/h3\u003e\n\u003cp\u003eA total of 174 patients with upper urinary tract stones were included, comprising 88 in the ambulatory surgery group and 86 in the inpatient group. Key demographic and clinical data are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Inpatients were significantly older than ambulatory patients (58.55\u0026thinsp;\u0026plusmn;\u0026thinsp;12.52 vs. 50.14\u0026thinsp;\u0026plusmn;\u0026thinsp;12.79 years, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with no sex disparity (P\u0026thinsp;=\u0026thinsp;0.923).ASA classification (P\u0026thinsp;=\u0026thinsp;0.108) and BMI (26.16\u0026thinsp;\u0026plusmn;\u0026thinsp;3.57 vs. 25.54\u0026thinsp;\u0026plusmn;\u0026thinsp;3.73, P\u0026thinsp;=\u0026thinsp;0.267) were comparable between groups. Inpatients had larger cumulative stone diameters (1.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.74 vs. 1.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57 cm, P\u0026thinsp;=\u0026thinsp;0.001) and longer operative times (53.09\u0026thinsp;\u0026plusmn;\u0026thinsp;26.64 vs. 41.30\u0026thinsp;\u0026plusmn;\u0026thinsp;21.45 min, P\u0026thinsp;=\u0026thinsp;0.002). No differences were observed in preoperative nephrostomy (P\u0026thinsp;=\u0026thinsp;0.254) or double-J stent placement rates (P\u0026thinsp;=\u0026thinsp;0.632). Hospitalization costs were higher for inpatients (\u0026yen;29,240.94\u0026thinsp;\u0026plusmn;\u0026thinsp;3,856.12 vs. \u0026yen;27,075.41\u0026thinsp;\u0026plusmn;\u0026thinsp;4,112.93, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Ambulatory patients had significantly shorter hospital stays (1.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.29 vs. 4.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.14 days, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Stone-free rates (82.95% vs. 80.23%, P\u0026thinsp;=\u0026thinsp;0.789) and complication rates (2.33% vs. 1.14%, P\u0026thinsp;=\u0026thinsp;0.491) were similar, with all complications being Clavien-Dindo grade I. No difference was found in 30-day readmission rates (P\u0026thinsp;=\u0026thinsp;0.506). One ambulatory patient (an elderly male with benign prostatic hyperplasia) was readmitted for febrile urinary retention and discharged after antibiotic therapy.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eClinical characteristics of patients\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInpatient surgery\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eambulatory surgery\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOverall\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;86)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;88)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;174)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e58.55 (12.52)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50.14 (12.79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e54.29 (13.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSex\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.923\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25 (29.07%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25 (28.41%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e50 (28.74%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e61 (70.93%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e63 (71.59%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e124 (71.26%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eASA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.108\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6 (6.98%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14 (15.91%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e20 (11.49%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e65 (75.58%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e65 (73.86%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e130 (74.71%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13 (15.12%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9 (10.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22 (12.64%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade IV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2 (2.32%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2 (1.16%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBMI\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.267\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e26.16 (3.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25.54 (3.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e25.85 (3.65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStone type\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.03\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSingle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e48 (55.81%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e63 (71.59%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e111 (63.79%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMultiple\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e38 (44.19%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25 (28.41%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e63 (36.21%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCumulative stone diameter\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.67 (0.74)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.34 (0.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.51 (0.68)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTime of surgery\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.002\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e53.09 (26.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e41.30 (21.45)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e47.13 (24.80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreoperative nephrostomy\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.254\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e86 (100.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e86 (97.73%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e172 (98.85%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2 (2.27%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2 (1.15%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreoperative stent\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.632\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e71 (82.56%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e75 (85.22%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e146 (83.91%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15 (17.44%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e13 (14.78%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e28 (16.09%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHospitalization costs\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e29240.94 (3856.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e27075.41 (4112.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e28145.73 (4122.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLength of stay (day)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4.29 (1.14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.09 (0.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.67 (1.80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSFR\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.789\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e80.23%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e82.95%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e81.61%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eReadmission\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.506\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e86 (100.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e87 (98.86%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e173 (99.43%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1 (1.14%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1 (0.57%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePostoperative complication\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.491\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e84 (97.67%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e87 (98.86%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e171 (98.28%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2 (2.33%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1 (1.14%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3 (1.72%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade III\u003c/p\u003e \u003cp\u003eGrade IV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e*P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 indicating statistical significance.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e: \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eClinical characteristics of total patients\u003c/span\u003e\u003c/p\u003e\n\u003ch3\u003e2. Subgroup Analysis of Ambulatory Patients\u003c/h3\u003e\n\u003cp\u003eEight ambulatory patients required overnight observation (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). These patients were older (64.1\u0026thinsp;\u0026plusmn;\u0026thinsp;13.2 vs. 48.7\u0026thinsp;\u0026plusmn;\u0026thinsp;11.5 years, P\u0026thinsp;=\u0026thinsp;0.001), predominantly female (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and had more comorbidities (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eClinical characteristics of Ambulatory patients\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNormal group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSpecial group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOverall\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;80)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;88)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e48.74 (11.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e64.13 (13.24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e50.14 (12.79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSex\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18 (22.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7 (87.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e25 (28.41%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e62 (77.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1 (12.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e63 (71.59%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eASA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14 (17.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14 (15.91%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e61 (76.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4 (50.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e65 (73.86%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5 (6.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4 (50.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e9 (10.23%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBMI\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.160\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25.36 (3.62)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e27.31 (4.58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e25.54 (3.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStone type\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.937\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSingle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e57 (71.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6 (75.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e63 (71.59%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMultiple\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e23 (28.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2 (25.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e24 (28.41%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCumulative stone diameter\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.622\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.33 (0.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.44 (0.59)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.34 (0.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTime of surgery\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.564\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e40.88 (19.53)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e45.50 (37.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e41.30 (21.45)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreoperative nephrostomy\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.175\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e79 (98.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7 (87.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e86 (97.73%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1 (1.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1 (12.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2 (2.27%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreoperative stent\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.092\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e70 (87.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5 (62.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e75 (85.23%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10 (12.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3 (37.50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13 (14.77%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHospitalization costs\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.552\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e26992.21 (4239.92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e27907.38 (2547.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e27075.41 (4112.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSFR\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e82.50%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e87.50%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e83.00%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eReadmission\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.909\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e79 (98.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8 (100.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e87 (98.86%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1 (1.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1 (1.14%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePostoperative complication\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.909\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e79 (98.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8 (100.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e87 (98.86%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1 (1.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1 (1.14%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e*P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 indicating statistical significance.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e: \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eClinical characteristics of Ambulatory patients\u003c/span\u003e\u003c/p\u003e\n\u003ch3\u003e3. Propensity Score Matching (PSM) Analysis\u003c/h3\u003e\n\u003cp\u003eAfter 1:1 PSM (matched for age, sex, cumulative stone diameter, and ASA grade; caliper\u0026thinsp;=\u0026thinsp;0.1), 57 matched pairs were analyzed (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).Baseline characteristics were balanced post-matching (all P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Ambulatory surgery was associated with shorter hospitalization (1.14\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35 vs. 4.16\u0026thinsp;\u0026plusmn;\u0026thinsp;1.10 days, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), while costs and stone-free rates showed no significant differences.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eClinical characteristics of patients after PSM\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInpatient surgery\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eambulatory surgery\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOverall\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;57)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;57)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;114)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.627\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e54.53 (11.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e54.58 (12.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e54.55 (11.85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSex\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.677\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17 (29.82%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15 (26.32%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e32 (28.07%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e40 (70.18%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e42 (73.68%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e82 (71.93%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eASA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.640\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5 (8.77%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2 (3.51%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7 (6.14%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e46 (80.70%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e49 (85.96%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e95 (83.33%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6 (10.53%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6 (10.53%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12 (10.53%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBMI\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.464\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25.86 (3.81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25.79 (3.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e25.83 (3.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStone type\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.695\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSingle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e36 (63.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e38 (66.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e74 (64.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMultiple\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e21 (36.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e19 (31.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e39 (34.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCumulative stone diameter\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.226\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.56 (0.74)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.50 (0.58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.53 (0.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTime of surgery\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.014\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e51.68 (26.94)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e43.07 (21.89)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e47.38 (24.82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreoperative nephrostomy\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.248\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e57 (100.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e55 (96.49%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e112 (98.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2 (3.51%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2 (1.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreoperative stent\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e46 (80.70%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46 (80.70%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e92 (80.70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e11 (19.30%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11 (19.30%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22 (19.30%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ecost\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.604\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e28682.23 (3843.68)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e27379.11 (3600.24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e28030.67 (3764.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLength of stay (day)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4.16 (1.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.14 (0.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.65 (1.72)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSFR\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.812\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e82.46%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e78.95%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e80.70%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eReadmission\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.500\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e57 (100.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e56 (98.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e113 (99.12%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0 (0.00%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1 (1.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1 (0.88%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePostoperative complication\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.752\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e56 (98.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e56 (98.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e112 (98.25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1 (1.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1 (1.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2 (1.75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e*P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 indicating statistical significance.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e: \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eClinical characteristics of patients after PSM\u003c/span\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis retrospective propensity score\u0026ndash;matched study systematically compared the safety, effectiveness, and health system impact of ambulatory versus inpatient flexible ureteroscopic lithotripsy (fURS) for upper urinary tract stones. Our findings demonstrate that, in carefully selected patients, ambulatory fURS achieves comparable stone-free rates and postoperative safety outcomes to conventional inpatient management, while significantly reducing hospitalization duration. These results support the feasibility of expanding ambulatory fURS within modern urological practice.\u003c/p\u003e \u003cp\u003eAfter adjustment for baseline differences using propensity score matching, no significant differences were observed between groups in terms of postoperative complications, stone-free rates, or 30-day readmission rates. Importantly, all recorded complications were minor (Clavien\u0026ndash;Dindo grade I), and no severe infectious or surgical adverse events occurred. These findings are consistent with previous reports indicating that fURS, when performed under standardized protocols, is associated with low morbidity. However, compared with earlier studies reporting complication rates ranging from 0.3% to over 30%\u003csup\u003e8\u003c/sup\u003e, the notably low complication rate in our cohort highlights the importance of strict perioperative management and patient selection.\u003c/p\u003e \u003cp\u003eSeveral factors may explain the favorable safety profile observed in the ambulatory group. First, rigorous preoperative infection control was implemented, including routine urine culture screening and culture-directed antibiotic therapy until confirmed negativity. Second, standardized intraoperative techniques\u0026mdash;such as routine use of ureteral access sheaths, controlled laser settings, and efforts to minimize intrarenal pressure\u0026mdash;likely reduced the risk of bacterial translocation and postoperative infection. Third, clearly defined discharge criteria and routine placement of double-J stents provided additional postoperative safety, enabling early discharge without increasing complication or readmission rates.\u003c/p\u003e \u003cp\u003eAlthough the overall outcomes were comparable, subgroup analysis within the ambulatory cohort revealed that a small proportion of patients required overnight observation. These patients were generally older, predominantly female, and had higher ASA classifications, suggesting a greater burden of comorbidities. This finding underscores the critical role of patient selection in ambulatory fURS. While most patients can be safely discharged within 24 hours, elderly individuals and those with multiple comorbid conditions may benefit from extended postoperative monitoring, even when managed within an ambulatory framework. Such risk stratification may help optimize safety while maintaining efficiency.\u003c/p\u003e \u003cp\u003eFrom a health-economic perspective, ambulatory fURS was associated with significantly shorter hospital stays both before and after matching. Although total hospitalization costs were lower in the ambulatory group before matching, this difference was no longer statistically significant after PSM adjustment. This finding suggests that the primary economic advantage of ambulatory fURS may not lie in direct cost reduction but rather in improved healthcare resource utilization. Shorter hospital stays can enhance bed turnover efficiency, reduce inpatient occupancy, and increase overall system capacity\u0026mdash;an increasingly important consideration in high-volume tertiary centers.\u003c/p\u003e \u003cp\u003eThis study has several limitations. Its retrospective single-center design introduces the possibility of selection bias, despite the use of propensity score matching. Additionally, all procedures were performed by a single experienced surgeon, which may limit the generalizability of the results to lower-volume or less-experienced centers. Long-term outcomes, including stone recurrence and patient-reported measures such as postoperative discomfort and satisfaction, were not assessed. Furthermore, indirect costs and broader societal economic impacts were not included in the cost analysis. Future multicenter prospective studies or randomized controlled trials are warranted to validate these findings and refine patient selection criteria.\u003c/p\u003e \u003cp\u003eIn conclusion, ambulatory fURS represents a safe and effective treatment option for selected patients with upper urinary tract stones. When performed under standardized perioperative protocols and appropriate patient selection, this model can substantially reduce hospitalization duration without compromising surgical outcomes or patient safety, thereby supporting more efficient utilization of healthcare resources.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAmbulatory fURS represents a safe and effective treatment option for selected patients with upper urinary tract stones. When performed under standardized perioperative protocols and appropriate patient selection, this model can substantially reduce hospitalization duration without compromising surgical outcomes or patient safety, thereby supporting more efficient utilization of healthcare resources.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eASA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAmerican Society of Anesthesiologists Physical Status Classification System\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBMI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eBody Mass Index\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003efURS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eflexible ureteroscopic lithotripsy\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\"\u003ePSM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ePropensity score matching\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 \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted in accordance with the Declaration of Helsinki (revised in 2013). The study was approved by the ethics board of the Peking University People’s Hospital Review Board (2024PHB170-001). Informed consent forms were signed by all patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from [Peking University People's Hospital] but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of [Peking University People's Hospital].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCong Tian and Jie Gu declare conflict of interest that they contributed equally to this work. Remaining all authors (Lianming Wang, Liulin Xiong, Bo Yang, Hao Hu, Tao Xu, Junjun Xu, Jun Liu) declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis project was supported by\u0026nbsp;Peking University People’s Hospital research and development funds (RDL2024-21, RDE2025-09, and RDE2023-11).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCong Tian: Project development, Data analysis, Manuscript writing\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eJie Gu: Project development, Data analysis, Manuscript writing\u003c/p\u003e\n\u003cp\u003eLianming Wang: Data analysis\u003c/p\u003e\n\u003cp\u003eLiulin Xiong:\u0026nbsp;Data collection\u003c/p\u003e\n\u003cp\u003eBo Yang:\u0026nbsp;Data collection\u003c/p\u003e\n\u003cp\u003eHao Hu:\u0026nbsp;Data collection\u003c/p\u003e\n\u003cp\u003eTao Xu:\u0026nbsp;Data collection\u003c/p\u003e\n\u003cp\u003eJunjun Xu:\u0026nbsp;Data collection\u003c/p\u003e\n\u003cp\u003eJun Liu: Project development, Manuscript editing\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eTan S, Yuan D, Su H, et al. Prevalence of urolithiasis in China: a systematic review and meta-analysis. BJU Int. 2024;133(1):34\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGeraghty RM, Davis NF, Tzelves L, et al. Best Practice in Interventional Management of Urolithiasis: An Update from the European Association of Urology Guidelines Panel for Urolithiasis 2022. Eur Urol focus. 2023;9(1):199\u0026ndash;208.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHe M, Dong Y, Cai W, et al. Recent advances in the treatment of renal stones using flexible ureteroscopys. Int J Surg (London England). 2024;110(7):4320\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShabana W, Oquendo F, Hodhod A, et al. Miniaturized Ambulatory Percutaneous Nephrolithotomy Versus Flexible Ureteroscopy in the Management of Lower Calyceal Renal Stones 10\u0026ndash;20 mm: A Propensity Score Matching Analysis. Urology. 2021;156:65\u0026ndash;70.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJohn J, Wisniewski P, Fieggen G, et al. Intrarenal Pressure in Retrograde Intrarenal Surgery: A Narrative Review. Urology. 2025;195:201\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSinger M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSingh AK, Shukla PK, Khan SW, et al. Using the Modified Clavien Grading System to Classify Complications of Percutaneous Nephrolithotomy. Curr Urol. 2018;11(2):79\u0026ndash;84.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrosso AA, Sessa F, Campi R, et al. Intraoperative and postoperative surgical complications after ureteroscopy, retrograde intrarenal surgery, and percutaneous nephrolithotomy: a systematic review. Minerva Urol Nephrol. 2021;73(3):309\u0026ndash;32.\u003c/span\u003e\u003c/li\u003e\u003c/ol\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":"Ambulatory surgery, Flexible ureteroscopic lithotripsy, Upper urinary tract stones, Efficacy, Safety","lastPublishedDoi":"10.21203/rs.3.rs-8587174/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8587174/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo evaluate the safety, efficacy, and health economic value of flexible ureteroscopic lithotripsy (fURS) for upper urinary tract stones in ambulatory surgery compared to traditional inpatient management.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective cohort study analyzed 174 fURS cases performed by a single surgeon between January and December 2024. Patients were divided into ambulatory and inpatient groups. Propensity score matching (PSM, 1:1 ratio) was applied to balance baseline differences. Demographic data, perioperative parameters, and outcomes including stone-free rate (SFR), complication rates (Clavien-Dindo classification), hospitalization duration, and costs were analyzed.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eA total of 174 patients with upper urinary tract stones were included. Pre-matching analysis revealed that the inpatient group had significantly older age (58.55\u0026thinsp;\u0026plusmn;\u0026thinsp;12.52 vs. 50.14\u0026thinsp;\u0026plusmn;\u0026thinsp;12.79 years, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), larger cumulative stone diameter (1.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.74 vs. 1.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57 cm, P\u0026thinsp;=\u0026thinsp;0.001), and longer operative time (53.09\u0026thinsp;\u0026plusmn;\u0026thinsp;26.64 vs. 41.30\u0026thinsp;\u0026plusmn;\u0026thinsp;21.45 min, P\u0026thinsp;=\u0026thinsp;0.002). No significant differences were observed in postoperative complications (2.33% vs. 1.14%, P\u0026thinsp;=\u0026thinsp;0.491) or SFR (86.05% vs. 89.66%, P\u0026thinsp;=\u0026thinsp;0.502). The ambulatory group demonstrated a 74.6% reduction in hospitalization duration (1.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.29 vs. 4.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.14 days, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and lower total costs (27,075.41\u0026thinsp;\u0026plusmn;\u0026thinsp;4,112.93 vs. 29,240.94\u0026thinsp;\u0026plusmn;\u0026thinsp;3,856.12 RMB, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Post-PSM analysis confirmed comparable baseline characteristics, with the ambulatory group maintaining shorter hospitalization (1.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31 vs. 4.05\u0026thinsp;\u0026plusmn;\u0026thinsp;1.08 days, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), while cost differences became non-significant (27,532\u0026thinsp;\u0026plusmn;\u0026thinsp;3,982 vs. 28,916\u0026thinsp;\u0026plusmn;\u0026thinsp;4,205 RMB, P\u0026thinsp;=\u0026thinsp;0.106).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eAmbulatory fURS represents a safe and effective treatment option for selected patients with upper urinary tract stones. When performed under standardized perioperative protocols and appropriate patient selection, this model can substantially reduce hospitalization duration without compromising surgical outcomes or patient safety, thereby supporting more efficient utilization of healthcare resources.\u003c/p\u003e","manuscriptTitle":"Is Ambulatory Flexible Ureteroscopic Lithotripsy Safe and Feasible? Evidence from a Propensity Score–Matched Cohort","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-12 15:08:17","doi":"10.21203/rs.3.rs-8587174/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-17T07:45:19+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-14T15:28:01+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-14T05:05:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"303111883323421935015986643061039406622","date":"2026-02-14T04:59:16+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-13T12:11:03+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-13T02:09:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"61481442924899061604116183442212647742","date":"2026-02-11T07:03:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"95924740763008414472989476502866285239","date":"2026-02-09T03:15:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"186046368366645900846544573997417834739","date":"2026-02-08T23:03:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"288440422485783604815483148139684270149","date":"2026-02-08T22:11:29+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-08T21:24:16+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-01-22T06:35:48+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-19T15:35:36+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-19T15:34:19+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Urology","date":"2026-01-13T04:30:29+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":"d631579d-cc5e-4cb2-b932-2e9de3189c25","owner":[],"postedDate":"February 12th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-13T16:09:58+00:00","versionOfRecord":{"articleIdentity":"rs-8587174","link":"https://doi.org/10.1186/s12894-026-02129-x","journal":{"identity":"bmc-urology","isVorOnly":false,"title":"BMC Urology"},"publishedOn":"2026-04-06 15:58:37","publishedOnDateReadable":"April 6th, 2026"},"versionCreatedAt":"2026-02-12 15:08:17","video":"","vorDoi":"10.1186/s12894-026-02129-x","vorDoiUrl":"https://doi.org/10.1186/s12894-026-02129-x","workflowStages":[]},"version":"v1","identity":"rs-8587174","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8587174","identity":"rs-8587174","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}