Clinical predictors of blood loss during mini-endoscopic combined intrarenal surgery

Clinical predictors of blood loss during mini-endoscopic combined intrarenal surgery | 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 Clinical predictors of blood loss during mini-endoscopic combined intrarenal surgery Hiroki Ito, Tetsuo Fukuda, Fukashi Yamamichi, Takahiko Watanabe, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7958967/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Mini-endoscopic combined intrarenal surgery (ECIRS) effectively treats renal and ureteral stones over percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) alone. However, factors influencing bleeding remain poorly understood. To mitigate bleeding during mini-ECIRS, we aimed to identify the factors associated with severe bleeding. Methods Clinical data from consecutive patients who underwent mini-ECIRS for renal and/or ureteral stones between 2015 and 2021 at three high-volume centers in Japan were analyzed. The inclusion criterion was mini-ECIRS with the modified Valdivia position. The primary outcome was the percentage of serum hemoglobin drop on postoperative day 1. Severe bleeding was defined as a ≥ 20% drop in hemoglobin or need for blood transfusion. Logistic regression models were used to identify the predictors of severe bleeding. Results Among 1333 patients, the mean hemoglobin drop was 9.6 ± 7.4%, and the transfusion rate was 0.5%. Severe bleeding occurred in 13.1% of the cases. Patients with severe bleeding had significantly higher residual stone rates (P = 0.005) and longer operative time (P = 0.005) than those without severe bleeding. Septic shock and arteriovenous fistulas (AVF) were also more frequent in the severe bleeding group (P 25 (OR: 1.885, 95% CI: 1.192–2.982, P = 0.007), and older age (OR: 1.017, 95% CI: 1.000–1.033, P = 0.047) were independent preoperative predictors of severe bleeding. Preoperative nephrostomy placement showed a trend toward reduced bleeding risk. Conclusions Severe bleeding during mini-ECIRS was associated with poorer surgical outcomes, including higher residual stone rates and an increased risk of septic shock and AVF. Male sex, obesity, older age, and longer operative time were the independent predictors. Preoperative nephrostomy may help reduce bleeding risk, supporting its selective use in high-risk patients to improve safety and stone-free outcomes. mini-endoscopic combined intrarenal surgery retrograde intrarenal surgery lithotripsy bleeding blood transfusion Figures Figure 1 1. Introduction Endoscopic combined intrarenal surgery (ECIRS) is an established technique that combines percutaneous nephroscopy and retrograde intrarenal surgery (RIRS) to effectively treat renal and ureteral stones. Compared with percutaneous nephrolithotomy (PCNL) alone, ECIRS offers improved stone clearance rates and potentially lower morbidity by leveraging dual access. 1 , 2 Miniaturization of percutaneous access has led to the development of mini-ECIRS, using smaller tract sizes to reduce postoperative pain and potentially minimize bleeding risks compared with conventional ECIRS. 3 Despite these theoretical advantages, robust clinical data specific to mini-ECIRS remain limited. Bleeding is a major complication of kidney stone surgery, 4 especially percutaneous surgery, including PCNL and ECIRS, and is associated with blood loss, often necessitating transfusion or angioembolization in severe cases. 5 A significant drop in serum hemoglobin levels has been associated with poorer surgical outcomes across various surgical domains, 6–8 and many studies have investigated the factors affecting bleeding during PCNL. 5 , 9 – 11 However, factors predicting bleeding during mini-ECIRS have not been systematically evaluated. This multicenter retrospective cohort study aimed to identify clinical predictors of severe bleeding during mini-ECIRS for urolithiasis. An improved understanding of these risk factors may facilitate better patient counseling, informed consent, and tailored perioperative strategies to minimize morbidity. 2. Materials and Methods The clinical information of consecutive patients who underwent conventional or mini-ECIRS for urinary stone disease between 2015 and 2021 at three high-volume centers in Japan (Yokosuka Kyosai Hospital, Ohguchi East General Hospital, and Hara Genitourinary Hospital) was collected and pooled for analysis, as previously reported. 12 The inclusion criterion was mini-ECIRS for the treatment of urolithiasis with a single tract under the modified Valdivia position. Exclusion criteria were conventional ECIRS with a large tract (≥ 20 Fr), multiple tract procedures, insufficient clinical information, and patients with urinary tract abnormalities, including horseshoe kidney, ileal conduit, neobladder, severe ureteral stricture, and ureteropelvic junction obstruction, not allowing RIRS to be performed during mini-ECIRS. The final treatment outcome was evaluated by percentage of serum hemoglobin drop at postoperative day 1, and a severe bleeding was defined as ≥ 20% drop of serum hemoglobin or necessity of blood transfusion. Non-contrast computed tomography imaging was used to evaluate surgical outcomes 1 month postoperatively, following the same protocol at the three institutions. Surgical success was defined by computed tomography imaging 1 month postoperatively as complete stone-free or residual stone fragments < 4 mm. Residual stone fragments ≥ 4 mm were defined as non-stone-free. 2.1 Surgical technique of mini-ECIRS The details of the surgical technique have been described previously. 12 Briefly, all procedures were performed under general anesthesia, with the patient in the modified Valdivia position. Each procedure was supervised by at least one urologist who had performed > 50 PCNL or ECIRS procedures. After insertion of the ureteral access sheath, ultrasound-guided caliceal puncture was performed. The tract was then dilated to insert a 17.5 Fr sheath using a one-step dilator. The final decision regarding the approach was made by experts based on the location and shape of the stone and the risk of damage to other organs. Stone fragmentation was performed using a pneumatic lithotripter or a Holmium:Yttrium-Aluminum-Garnet laser, and passive fragment retrieval was performed using irrigation from the ureteral access sheath. The three indications for ureteral stenting or nephrostomy prior to surgery were as follows: pain relief from the stones, febrile pyelonephritis, and renal dysfunction due to hydronephrosis. Otherwise, drainage was not performed before ECIRS to minimize the deterioration of the patients’ quality of life. 2.2 Ethics declarations This study was conducted in accordance with the principles of the Declaration of Helsinki. Informed consent was obtained from participants using the opt-out method on each hospital website. The requirement for written informed consent was waived and the study protocol was approved by the institutional ethics committee of each hospital. (institutional review board number 20–90 at Yokosuka Kyosai Hospital, 202201 at Ohguchi East General Hospital, and 2021-05-06 at Hara Genitourinary Hospital). 2.3 Statistical analyses Statistical analyses were performed using Statistical Package for Social Sciences version 28.0 (SPSS, IBM Corp. Released 2021. IBM SPSS Statistics for Windows, Version 28.0. Armonk, NY: IBM Corp). Shapiro–Wilk test was performed to check the normality, and all data are expressed as mean ± standard error of the mean. Patient characteristics and preoperative factors were analyzed using the unpaired t-test and chi-square test, respectively. Multivariate logistic regression models with forced entry were used for the statistical analysis. Statistical significance was set at P < 0.05. 3. Results 3.1 Patient and stone characteristics The multi-center cohort database included 1432 cases, 1333 of 1432 cases met the inclusion criteria for this study (Fig. 1 ). In overall cohort, the average percentage of hemoglobin drop from baseline were − 9.6 ± 7.4%, and blood transfusion rate was 0.5% (6/1333 cases). Table 1 shows a comparison of patient characteristics based on the blood loss status. Significant differences were found between the two groups in terms of age (P = 0.011), body mass index (BMI) (P < 0.001), sex (P < 0.001), operative duration (P = 0.006), and postoperative hospital stay (P < 0.001). Table 1 Baseline patient and stone characteristics according to bleeding status. Values are presented as mean ± standard error of the mean or number (percentage). Non-severe bleeding Severe bleeding P value No. of patients (cases) 1222 111 Age (years) 57.5 ± 12.9 60.7 ± 12.4 0.011 Sex female (cases) 849 (69.5%) 57 (51.4%) < 0.001 male (cases) 373 (30.5%) 54 (48.6%) ECOG-PS 0 1143 (93.5%) 102 (91.9%) 0.871 1 43 (3.5%) 4 (3.6%) 2 10 (0.8%) 1 (0.9%) 3 9 (0.7%) 1 (0.9%) 4 17 (1.4%) 3 (2.7%) Side right (cases) 554 (45.3%) 59 (53.2%) 0.114 Body mass index (cm/kg2) 24.4 ± 4.7 22.8 ± 4.0 < 0.001 Number of stones 3.0 ± 2.4 2.9 ± 2.4 0.838 Stone diameter (mm) 36.4 ± 21.1 35.5 ± 19.4 0.659 No. of calyx involving stone 2.2 ± 1.8 2.4 ± 2.0 0.329 Presence of intrapelvis and/or intracalyces stone 1026 (84%) 99 (89.2%) 0.146 Presence of ureteral stone 321 (26.3%) 20 (18.0%) 0.056 Hydronephrosis (cases) 796 (65.1%) 66 (59.5%) 0.231 Preoperative stenting (cases) 359 (29.4%) 25 (22.5%) 0.127 Preoperative nephrostomy (cases) 108 (8.8%) 5 (4.5%) 0.117 3.2 Treatment outcome Table 2 shows a comparison of treatment outcomes according to the blood loss status. Patients with severe bleeding had significantly higher residual stone rates (P = 0.005) and longer operative time (P = 0.005) than those without severe bleeding. Septic shock and arteriovenous fistula (AVF) were more frequent in the severe bleeding group than in the non-severe bleeding group (P < 0.001). Table 2 Comparison of treatment outcomes between patients with severe bleeding and those without. Values are presented as mean ± standard error of the mean or number (percentage). Non-severe bleeding Severe bleeding P value No. of patients (cases) 1222 111 Operative time (min) 112.1 ± 33.3 121.1 ± 32.0 0.005 Punctured pole Upper 617 (51.2%) 59 (54.6%) 0.773 Middle 310 (25.7%) 25 (23.1%) Lower 278 (23.1%) 24 (22.2%) Postoperative stenting (cases) 782 (64%) 75 (67.6%) 0.452 Postoperative nephrostomy (cases) 827 (67.7%) 83 (74.8%) 0.124 Postoperative admission days 5.4 ± 3.0 6.6 ± 5.5 < 0.001 Serum hemoglobin Preoperative 14.1 ± 1.8 14.0 ± 1.6 0.295 1 day after surgery 13.0 ± 1.7 10.5 ± 1.5 < 0.001 Drop rate from preoperative value (%) -8.3 ± 6.0 -24.9 ± 5.0 < 0.001 Stone free status Residual fragments more than 4mm 408 (33.4%) 55 (49.5%) 0.005 Postoperative complications Septic shock 15 (1.2%) 10 (9.0%) < 0.001 AVF 2 (0.2% 3 (2.7%) < 0.001 Organ injury 7 (0.6%) 0 0.424 Bleeding necessiating blood transfusion 0 6 (5.4%) < 0.001 Stone composition Calcium oxalate 475 (39%) 44 (40%) 0.597 Calcium phosphate 89 (7.3%) 7 (6.4%) Uric acid 28 (2.3%) 3 (2.7%) MAP 32 (2.6%) 6 (5.5%) Mixed 547 (44.9%) 48 (43.6%) Other 37 (3%) 2 (1.8%) Unclear 14 (1.1%) 1 (0.1%) 3.3 Multivariate logistic regression analysis to detect preoperative clinical factors associated with severe bleeding during mini-ECIRS Male sex (odds ratio [OR]: 1.904, 95% confidence interval [CI]: 1.263–2.870, P = 0.002), BMI > 25 (OR: 1.885, 95% CI: 1.192–2.982, P = 0.007), and older age (OR: 1.017, 95% CI: 1.000–1.033, P = 0.047) were significant predictive factors for severe bleeding during mini-ECIRS (Table 3 ). Preoperative placement of nephrostomy was associated with less severe bleeding during mini-ECIRS (OR: 0.372, 95% CI: 1.131 − 1.054, P = 0.063). Table 3 Multivariate logistic regression analysis of preoperative clinical factors predicting severe bleeding during mini-endoscopic combined intrarenal surgery. 95% C.I. of O.R. P value Odds ratio (O.R.) Lower Upper Age 0.047 1.0 1.0 1.0 BMI 25 > vs 25≤ 0.007 1.9 1.2 3.0 Sex Male vs Female 0.002 1.9 1.3 2.9 Stone diameter 0.376 1.0 1.0 1.0 Number of involved calyces 0.669 1.0 0.9 1.2 Presence of hydronephrosis 0.440 0.8 0.6 1.3 Preoperative stenting 0.092 0.7 0.4 1.1 Preoperative nephrostomy 0.063 0.4 0.1 1.1 Presence of intrapelvis and/or intracalyces stones 0.369 1.4 0.7 2.7 3.4 Multivariate logistic regression analysis to detect pre- and intraoperative clinical factors associated with severe bleeding during mini-ECIRS Male sex (OR: 1.932, 95% CI: 1.269–2.939, P = 0.002), operative duration (OR: 1.918, 95% CI: 1.271–2.896, P = 0.002), and BMI > 25 (OR: 1.950, 95% CI: 1.222–3.114, P = 0.005) were significant predictive factors for severe bleeding during mini-ECIRS (Table 4 ). Preoperative placement of nephrostomy (OR: 0.407, 95% CI: 0.143 − 1.159, P = 0.092) and age (OR: 1.016, 95% CI: 0.999 − 1.033, P = 0.065) were associated with less severe bleeding during mini-ECIRS. Table 4 Multivariate logistic regression analysis including pre- and intraoperative factors predicting severe bleeding during mini-endoscopic combined intrarenal surgery. 95% C.I. of O.R. P value Odds ratio (O.R.) Lower Upper Age 0.065 1.016 0.999 1.033 BMI 25 > vs 25≤ 0.005 1.950 1.222 3.114 Sex Male vs Female 0.002 1.932 1.269 2.939 Stone diameter 0.298 0.994 0.982 1.006 Number of involved calyces 0.949 1.004 0.884 1.140 Presence of hydronephrosis 0.419 0.835 0.538 1.294 Preoperative stenting 0.152 0.701 0.431 1.140 Preoperative nephrostomy 0.092 0.407 0.143 1.159 Presence of intrapelvis and/or intracalyces stones 0.227 1.554 0.760 3.177 Punctured pole Middle vs Upper pole 0.598 0.872 0.524 1.451 Lower vs Upper pole 0.655 0.888 0.526 1.498 Operative duration 0.002 1.918 1.271 2.896 4. Discussion This multicenter study is the first to investigate the risk factors of severe bleeding during mini-ECIRS. We found that severe bleeding, defined as a postoperative hemoglobin drop exceeding 20%, or the need for transfusion, was independently associated with male sex, BMI > 25, older age, and longer operative duration. Preoperative nephrostomy placement could mitigate bleeding risk. Excessive bleeding is associated with poorer surgical outcomes in various surgeries, 6–8 and the cutoff point is usually set at a hemoglobin drop of ≥ 2 g/dL. 13 This study set the threshold at a 20% hemoglobin drop because the percentage value should not be more biased than the actual drop in hemoglobin levels, such as 2 g/dL. In fact, we found a significant difference in the preoperative hemoglobin levels of patients when divided by a ≥ 2 g/dL drop in hemoglobin. In this cohort, severe bleeding was associated with higher rates of septic shock and AVF formation, justifying the clinical importance of the 20% drop criterion. There is no doubt that the evidence for ECIRS is sparse, whereas many studies have found some predictors of perioperative bleeding in PCNL. Diabetes, multiple tract procedures, prolonged operative time, middle calix puncture, and the occurrence of intraoperative complications, but not surgical experience, are significantly associated with increased blood loss during PCNL. 9 , 10 , 14 Meanwhile, diabetes mellitus, staghorn stones, and multiple tracts were identified as significant factors associated with severe hemorrhage post PCNL. 5 Unfortunately, our database does not contain diabetes history and excludes multiple tract procedures because of the small sample size; thus, we could not directly compare our results with previous findings of PCNL. However, the findings from PCNL did not detect male sex, BMI, or age as predictors, suggesting that physicians should consider mini-ECIRS as a different surgery from PCNL for the management of blood loss complications. Male sex emerged as a risk factor in this study; however, the reasons remain speculative. Potential explanations include anatomical differences in the vascular supply, variations in baseline hemoglobin levels, or differences in body composition affecting tract creation. Multiple studies have identified the male sex as a significant risk factor for increased blood loss during and after surgery. This has been observed in various surgical procedures, including pancreatectomy, 15 thyroidectomy, 16 and total knee arthroplasty. 17 Although the exact reasons for this are still being investigated, factors such as increased muscle mass in males, which may lead to the reopening of coagulated vessels or dislodging sutures, have been suggested as potential contributors to this increased bleeding tendency. 16 , 17 Higher BMI was also an independent predictor of severe bleeding in this study. Notably, the success of ECIRS requires proper percutaneous puncturing, and obesity may complicate percutaneous access by increasing the tract length or requiring repeated puncture attempts, leading to greater vascular injury. Although the “high BMI and higher bleeding” phenomenon has been noted in other surgeries such as open partial nephrectomy, 18 some studies showed higher BMI decreased significant blood loss during coronary artery bypass graft surgeries. 19 Some authors described this heterogeneity in the influence of BMI on surgical outcome as the BMI paradox 20 and hypothesized that exceeding the average BMI, irrespective of low and high, may cause surgical complications. Older age is also a predictor of an increased risk of bleeding. Age-related vascular fragility, reduced coagulation reserves, and comorbidities may contribute to this risk. 21 Surgeons should be mindful of these risks during preoperative counseling and planning. Longer operative duration was another key predictor, likely reflecting increased technical complexity, stone burden, or intraoperative bleeding, prolonging the procedure in a feedback loop. Our results also demonstrate that the severe bleeding group had a significantly higher rate of residual stone formation. One possible explanation is that intraoperative bleeding may obscure the surgical field, thereby complicating complete stone clearance. Excessive bleeding can impair visibility during percutaneous access and fragmentation, leading to the incomplete retrieval of stone fragments. Moreover, the prolonged operative time associated with difficult hemostasis may increase the risk of leaving residual fragments. These findings highlight the importance of anticipating the preoperative bleeding risk and adopting strategies to minimize blood loss and improve stone-free outcomes. Preoperative nephrostomy placement showed a trend toward reduced bleeding risk. This finding is particularly noteworthy, as it may represent the only modifiable preoperative intervention available to surgeons. By providing a preformed tract, a nephrostomy can reduce vascular trauma by eliminating the need for immediate tract dilation during surgery and minimizing repeated puncture attempts. Additionally, for the RIRS component, a lower intrarenal pressure can be achieved from the beginning of mini-ECIRS, which may help reduce bleeding and infection risks. Although preoperative nephrostomy can negatively affect patient’s quality of life, its selective use in high-risk patients should be considered as a strategy to improve safety and outcomes. The limitations of our study include its retrospective design, multisurgeon variability, and reliance on hemoglobin drop levels rather than direct blood loss measurements. The stone burden was assessed by maximum diameter rather than volume, although volume may better predict procedural complexity. 5. Conclusion Severe bleeding during mini-ECIRS is a clinically significant complication associated with increased morbidity. Identifying risk factors, such as sex, BMI, age, and operative duration, can guide individualized treatment planning. The selective use of preoperative nephrostomy may help reduce the risk of bleeding in high-risk patients. Future prospective studies are warranted to validate these findings and refine the risk prediction models. Abbreviations ECIRS = endoscopic combined intrarenal surgery RIRS = retrograde intrarenal surgery PCNL = percutaneous nephrolithotomy BMI = body mass index AVF = arteriovenous fistula OD = odds ratio CI = confidence interval Declarations Data availability statement The datasets generated and analyzed in the current study are not publicly available but can be obtained from the corresponding author upon reasonable request. Acknowledgments We would like to thank Editage (http://www.editage.com) for editing and reviewing this manuscript for English language Authorship contribution statement Ito H: Protocol/project development; Data collection or management; Data analysis; Manuscript writing/editing. Fukuda T: Data collection or management. Yamamichi F: Data collection or management. Watanabe T: Data collection or management. Shibata Y: Data collection or management. Tabei T: Data analysis. Makiyama K: Protocol/project development. Inoue T: Protocol/project development. Matsuzaki J: Protocol/project development. Kobayashi K: Protocol/project development. All authors have read and approved the final manuscript. Conflict of interest The authors declare no competing interests. Funding No funding was received for this research. References Perrella R, Vicentini FC, Neto MMP, et al. Endoscopic Combined Intra Renal Surgery versus Percutanous Nephrolithotomy: utcomes of a matched case-control analyis. World journal of urology 2025;43(1):275, doi:10.1007/s00345-025-05455-1 Abdullatif VA, Sur RL, Abdullatif ZA, et al. The Safety and Efficacy of Endoscopic Combined Intrarenal Surgery (ECIRS) versus Percutaneous Nephrolithotomy (PCNL): A Systematic Review and Meta-Analysis. Advances in urology 2022;2022(1716554, doi:10.1155/2022/1716554 Hamamoto S, Yasui T, Okada A, et al. Endoscopic combined intrarenal surgery for large calculi: simultaneous use of flexible ureteroscopy and mini-percutaneous nephrolithotomy overcomes the disadvantageous of percutaneous nephrolithotomy monotherapy. Journal of endourology / Endourological Society 2014;28(1):28-33, doi:10.1089/end.2013.0361 Perri D, Besana U, Maltagliati M, et al. Risk of bleeding after retrograde intrarenal surgery vs miniaturised percutaneous nephrolithotomy for 10-20 mm renal stones: a not so different safety profile. BJU international 2025;135(3):497-501, doi:10.1111/bju.16585 Li Z, Wu A, Liu J, et al. Risk factors for hemorrhage requiring embolization after percutaneous nephrolithotomy: a meta-analysis. Transl Androl Urol 2020;9(2):210-217, doi:10.21037/tau.2020.01.10 Kalra SK, Thilagar B, Khambaty M, et al. Post-operative Anemia After Major Surgery: a Brief Review. Current Emergency and Hospital Medicine Reports 2021;9(3):89-95, doi:10.1007/s40138-021-00232-x Jung DH, Lee HJ, Han DS, et al. Impact of perioperative hemoglobin levels on postoperative outcomes in gastric cancer surgery. Gastric Cancer 2013;16(3):377-82, doi:10.1007/s10120-012-0196-8 Salciccia S, Rosati D, Viscuso P, et al. Influence of operative time and blood loss on surgical margins and functional outcomes for laparoscopic versus robotic-assisted radical prostatectomy: a prospective analysis. Cent European J Urol 2021;74(4):503-515, doi:10.5173/ceju.2021.0177 Akman T, Binbay M, Sari E, et al. Factors affecting bleeding during percutaneous nephrolithotomy: single surgeon experience. Journal of endourology / Endourological Society 2011;25(2):327-33, doi:10.1089/end.2010.0302 Kukreja R, Desai M, Patel S, et al. Factors affecting blood loss during percutaneous nephrolithotomy: prospective study. Journal of endourology / Endourological Society 2004;18(8):715-22, doi:10.1089/end.2004.18.715 Poudyal S. Current insights on haemorrhagic complications in percutaneous nephrolithotomy. Asian J Urol 2022;9(1):81-93, doi:10.1016/j.ajur.2021.05.007 Ito H, Sakamaki K, Fukuda T, et al. Models to predict the surgical outcome of mini-ECIRS (endoscopic combined intrarenal surgery) for renal and/or ureteral stones. Sci Rep 2023;13(1):22848, doi:10.1038/s41598-023-50022-6 Polverino F, Di Bello F, Morra S, et al. Predictive factors of hemoglobin drop after robot-assisted radical prostatectomy: a single center prospective study. J Robot Surg 2024;18(1):337, doi:10.1007/s11701-024-02093-4 Ramon de Fata F, Perez D, Resel-Folkersma L, et al. Analysis of the factors affecting blood loss in percutaneous nephrolithotomy: a registry of the Spanish Association of Urology in the supine position. Actas urologicas espanolas 2013;37(9):527-32, doi:10.1016/j.acuro.2013.05.001 Mazmudar A, Vitello D, Chapman M, et al. Gender as a risk factor for adverse intraoperative and postoperative outcomes of elective pancreatectomy. J Surg Oncol 2017;115(2):131-136, doi:10.1002/jso.24488 Lee D, Back K, Choe J-H, et al. Risk Factors for Post-Thyroidectomy Bleeding: an Analysis of 19,657 Cases from a Single Institution. Journal of Endocrine Surgery 2020;20(4), doi:10.16956/jes.2020.20.4.60 Wu EB, Hung KC, Juang SE, et al. Are Risk Factors for Postoperative Significant Hemorrhage following Total Knee Arthroplasty Potentially Modifiable? A Retrospective Cohort Study. J Pers Med 2022;12(3), doi:10.3390/jpm12030434 Kaneko G, Miyajima A, Kikuchi E, et al. The benefit of laparoscopic partial nephrectomy in high body mass index patients. Jpn J Clin Oncol 2012;42(7):619-24, doi:10.1093/jjco/hys061 Nolan HR, Davenport DL, Ramaiah C. BMI Is an Independent Preoperative Predictor of Intraoperative Transfusion and Postoperative Chest-Tube Output. Int J Angiol 2013;22(1):31-6, doi:10.1055/s-0033-1333865 Kott O, Golijanin B, Pereira JF, et al. The BMI Paradox and Robotic Assisted Partial Nephrectomy. Front Surg 2019;6(74, doi:10.3389/fsurg.2019.00074 Clegg A, Young J, Iliffe S, et al. Frailty in elderly people. Lancet 2013;381(9868):752-62, doi:10.1016/S0140-6736(12)62167-9 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7958967","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":539069977,"identity":"057cd8d8-6e22-47ff-b4ef-285678339bea","order_by":0,"name":"Hiroki 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08:48:53","extension":"xml","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":86668,"visible":true,"origin":"","legend":"","description":"","filename":"3b04d5c8a6e84892b3ad36aeea4e0d711structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7958967/v1/13ca612bd785a95308130ff6.xml"},{"id":95807974,"identity":"5b043543-bf06-46cd-bc4f-dc0cce406c93","added_by":"auto","created_at":"2025-11-13 08:49:16","extension":"html","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":94193,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7958967/v1/28114c230fbad3dd2d1592dd.html"},{"id":95808114,"identity":"a7ae00eb-501b-49e7-93ad-42ccf1af1911","added_by":"auto","created_at":"2025-11-13 08:49:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":659996,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of patient selection and inclusion in the analysis cohort. A total of 1432 cases were screened; 1333 met inclusion criteria for mini-endoscopic combined intrarenal surgery and were analyzed for bleeding outcomes.\u003c/p\u003e\n\u003cp\u003eECIRS, endoscopic combined intrarenal surgery\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7958967/v1/2fa808e97b42d5af13d82ddd.png"},{"id":98848010,"identity":"f6b89514-0ea9-4f7d-8b4d-acf2d86510d3","added_by":"auto","created_at":"2025-12-23 05:10:04","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1540624,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7958967/v1/77af4b42-7b96-4b80-b82e-5a816a2d90c7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Clinical predictors of blood loss during mini-endoscopic combined intrarenal surgery","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eEndoscopic combined intrarenal surgery (ECIRS) is an established technique that combines percutaneous nephroscopy and retrograde intrarenal surgery (RIRS) to effectively treat renal and ureteral stones. Compared with percutaneous nephrolithotomy (PCNL) alone, ECIRS offers improved stone clearance rates and potentially lower morbidity by leveraging dual access.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e Miniaturization of percutaneous access has led to the development of mini-ECIRS, using smaller tract sizes to reduce postoperative pain and potentially minimize bleeding risks compared with conventional ECIRS.\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e Despite these theoretical advantages, robust clinical data specific to mini-ECIRS remain limited.\u003c/p\u003e\u003cp\u003eBleeding is a major complication of kidney stone surgery,\u003csup\u003e4\u003c/sup\u003e especially percutaneous surgery, including PCNL and ECIRS, and is associated with blood loss, often necessitating transfusion or angioembolization in severe cases.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e A significant drop in serum hemoglobin levels has been associated with poorer surgical outcomes across various surgical domains,\u003csup\u003e6\u0026ndash;8\u003c/sup\u003e and many studies have investigated the factors affecting bleeding during PCNL.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e However, factors predicting bleeding during mini-ECIRS have not been systematically evaluated.\u003c/p\u003e\u003cp\u003eThis multicenter retrospective cohort study aimed to identify clinical predictors of severe bleeding during mini-ECIRS for urolithiasis. An improved understanding of these risk factors may facilitate better patient counseling, informed consent, and tailored perioperative strategies to minimize morbidity.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cp\u003eThe clinical information of consecutive patients who underwent conventional or mini-ECIRS for urinary stone disease between 2015 and 2021 at three high-volume centers in Japan (Yokosuka Kyosai Hospital, Ohguchi East General Hospital, and Hara Genitourinary Hospital) was collected and pooled for analysis, as previously reported.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e The inclusion criterion was mini-ECIRS for the treatment of urolithiasis with a single tract under the modified Valdivia position. Exclusion criteria were conventional ECIRS with a large tract (\u0026ge;\u0026thinsp;20 Fr), multiple tract procedures, insufficient clinical information, and patients with urinary tract abnormalities, including horseshoe kidney, ileal conduit, neobladder, severe ureteral stricture, and ureteropelvic junction obstruction, not allowing RIRS to be performed during mini-ECIRS.\u003c/p\u003e\u003cp\u003eThe final treatment outcome was evaluated by percentage of serum hemoglobin drop at postoperative day 1, and a severe bleeding was defined as \u0026ge;\u0026thinsp;20% drop of serum hemoglobin or necessity of blood transfusion. Non-contrast computed tomography imaging was used to evaluate surgical outcomes 1 month postoperatively, following the same protocol at the three institutions. Surgical success was defined by computed tomography imaging 1 month postoperatively as complete stone-free or residual stone fragments\u0026thinsp;\u0026lt;\u0026thinsp;4 mm. Residual stone fragments\u0026thinsp;\u0026ge;\u0026thinsp;4 mm were defined as non-stone-free.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Surgical technique of mini-ECIRS\u003c/h2\u003e\u003cp\u003eThe details of the surgical technique have been described previously.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e Briefly, all procedures were performed under general anesthesia, with the patient in the modified Valdivia position. Each procedure was supervised by at least one urologist who had performed\u0026thinsp;\u0026gt;\u0026thinsp;50 PCNL or ECIRS procedures. After insertion of the ureteral access sheath, ultrasound-guided caliceal puncture was performed. The tract was then dilated to insert a 17.5 Fr sheath using a one-step dilator. The final decision regarding the approach was made by experts based on the location and shape of the stone and the risk of damage to other organs. Stone fragmentation was performed using a pneumatic lithotripter or a Holmium:Yttrium-Aluminum-Garnet laser, and passive fragment retrieval was performed using irrigation from the ureteral access sheath. The three indications for ureteral stenting or nephrostomy prior to surgery were as follows: pain relief from the stones, febrile pyelonephritis, and renal dysfunction due to hydronephrosis. Otherwise, drainage was not performed before ECIRS to minimize the deterioration of the patients\u0026rsquo; quality of life.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Ethics declarations\u003c/h2\u003e\u003cp\u003e This study was conducted in accordance with the principles of the Declaration of Helsinki. Informed consent was obtained from participants using the opt-out method on each hospital website. The requirement for written informed consent was waived and the study protocol was approved by the institutional ethics committee of each hospital. (institutional review board number 20\u0026ndash;90 at Yokosuka Kyosai Hospital, 202201 at Ohguchi East General Hospital, and 2021-05-06 at Hara Genitourinary Hospital).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Statistical analyses\u003c/h2\u003e\u003cp\u003eStatistical analyses were performed using Statistical Package for Social Sciences version 28.0 (SPSS, IBM Corp. Released 2021. IBM SPSS Statistics for Windows, Version 28.0. Armonk, NY: IBM Corp). Shapiro\u0026ndash;Wilk test was performed to check the normality, and all data are expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard error of the mean. Patient characteristics and preoperative factors were analyzed using the unpaired t-test and chi-square test, respectively. Multivariate logistic regression models with forced entry were used for the statistical analysis. Statistical significance was set at P\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Patient and stone characteristics\u003c/h2\u003e\u003cp\u003eThe multi-center cohort database included 1432 cases, 1333 of 1432 cases met the inclusion criteria for this study (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). In overall cohort, the average percentage of hemoglobin drop from baseline were \u0026minus;\u0026thinsp;9.6\u0026thinsp;\u0026plusmn;\u0026thinsp;7.4%, and blood transfusion rate was 0.5% (6/1333 cases).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows a comparison of patient characteristics based on the blood loss status. Significant differences were found between the two groups in terms of age (P\u0026thinsp;=\u0026thinsp;0.011), body mass index (BMI) (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), sex (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), operative duration (P\u0026thinsp;=\u0026thinsp;0.006), and postoperative hospital stay (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\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\u003eBaseline patient and stone characteristics according to bleeding status. Values are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard error of the mean or number (percentage).\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNon-severe bleeding\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eSevere bleeding\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eP value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eNo. of patients (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1222\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e111\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eAge (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e57.5\u0026thinsp;\u0026plusmn;\u0026thinsp;12.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e60.7\u0026thinsp;\u0026plusmn;\u0026thinsp;12.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.011\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSex\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003efemale (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e849 (69.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e57 (51.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003emale (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e373 (30.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e54 (48.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eECOG-PS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1143 (93.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e102 (91.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.871\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e43 (3.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4 (3.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e10 (0.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (0.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e9 (0.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (0.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e17 (1.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3 (2.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSide\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eright (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e554 (45.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e59 (53.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.114\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eBody mass index (cm/kg2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e24.4\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e22.8\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eNumber of stones\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.838\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eStone diameter (mm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e36.4\u0026thinsp;\u0026plusmn;\u0026thinsp;21.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e35.5\u0026thinsp;\u0026plusmn;\u0026thinsp;19.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.659\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo. of calyx involving stone\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\u003cp\u003e2.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.329\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003ePresence of intrapelvis and/or intracalyces stone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1026 (84%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e99 (89.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.146\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePresence of ureteral stone\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\u003cp\u003e321 (26.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e20 (18.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.056\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eHydronephrosis (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e796 (65.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e66 (59.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.231\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003ePreoperative stenting (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e359 (29.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e25 (22.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.127\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003ePreoperative nephrostomy (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e108 (8.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5 (4.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.117\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Treatment outcome\u003c/h2\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows a comparison of treatment outcomes according to the blood loss status. Patients with severe bleeding had significantly higher residual stone rates (P\u0026thinsp;=\u0026thinsp;0.005) and longer operative time (P\u0026thinsp;=\u0026thinsp;0.005) than those without severe bleeding. Septic shock and arteriovenous fistula (AVF) were more frequent in the severe bleeding group than in the non-severe bleeding group (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\u003eComparison of treatment outcomes between patients with severe bleeding and those without. Values are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard error of the mean or number (percentage).\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNon-severe bleeding\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eSevere bleeding\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eP value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eNo. of patients (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1222\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e111\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOperative time (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e112.1\u0026thinsp;\u0026plusmn;\u0026thinsp;33.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e121.1\u0026thinsp;\u0026plusmn;\u0026thinsp;32.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.005\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePunctured pole\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eUpper\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e617 (51.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e59 (54.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.773\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eMiddle\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e310 (25.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e25 (23.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eLower\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e278 (23.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e24 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePostoperative stenting (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e782 (64%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e75 (67.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.452\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003ePostoperative nephrostomy (cases)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e827 (67.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e83 (74.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.124\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003ePostoperative admission days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6.6\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\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\u003eSerum hemoglobin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePreoperative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e14.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e14.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.295\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 day after surgery\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDrop rate from preoperative value (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-8.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-24.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\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\u003eStone free status\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eResidual fragments more than 4mm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e408 (33.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e55 (49.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.005\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePostoperative complications\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSeptic shock\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15 (1.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10 (9.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAVF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2 (0.2%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3 (2.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOrgan injury\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7 (0.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.424\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBleeding necessiating blood transfusion\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6 (5.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\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\u003eStone composition\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eCalcium oxalate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e475 (39%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e44 (40%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.597\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eCalcium phosphate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e89 (7.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e7 (6.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eUric acid\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e28 (2.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3 (2.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMAP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e32 (2.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6 (5.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eMixed\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e547 (44.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e48 (43.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOther\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e37 (3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2 (1.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eUnclear\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e14 (1.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (0.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Multivariate logistic regression analysis to detect preoperative clinical factors associated with severe bleeding during mini-ECIRS\u003c/h2\u003e\u003cp\u003eMale sex (odds ratio [OR]: 1.904, 95% confidence interval [CI]: 1.263\u0026ndash;2.870, P\u0026thinsp;=\u0026thinsp;0.002), BMI\u0026thinsp;\u0026gt;\u0026thinsp;25 (OR: 1.885, 95% CI: 1.192\u0026ndash;2.982, P\u0026thinsp;=\u0026thinsp;0.007), and older age (OR: 1.017, 95% CI: 1.000\u0026ndash;1.033, P\u0026thinsp;=\u0026thinsp;0.047) were significant predictive factors for severe bleeding during mini-ECIRS (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Preoperative placement of nephrostomy was associated with less severe bleeding during mini-ECIRS (OR: 0.372, 95% CI: 1.131\u0026thinsp;\u0026minus;\u0026thinsp;1.054, P\u0026thinsp;=\u0026thinsp;0.063).\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\u003eMultivariate logistic regression analysis of preoperative clinical factors predicting severe bleeding during mini-endoscopic combined intrarenal surgery.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e95% C.I. of O.R.\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eP value\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOdds ratio (O.R.)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eLower\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eUpper\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.047\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25\u0026thinsp;\u0026gt;\u0026thinsp;vs 25\u0026le;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.007\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSex\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMale vs Female\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.002\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStone diameter\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.376\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of involved calyces\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.669\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePresence of hydronephrosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.440\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePreoperative stenting\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.092\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePreoperative nephrostomy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.063\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePresence of intrapelvis and/or intracalyces stones\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.369\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e3.4 Multivariate logistic regression analysis to detect pre- and intraoperative clinical factors associated with severe bleeding during mini-ECIRS\u003c/p\u003e\u003cp\u003eMale sex (OR: 1.932, 95% CI: 1.269\u0026ndash;2.939, P\u0026thinsp;=\u0026thinsp;0.002), operative duration (OR: 1.918, 95% CI: 1.271\u0026ndash;2.896, P\u0026thinsp;=\u0026thinsp;0.002), and BMI\u0026thinsp;\u0026gt;\u0026thinsp;25 (OR: 1.950, 95% CI: 1.222\u0026ndash;3.114, P\u0026thinsp;=\u0026thinsp;0.005) were significant predictive factors for severe bleeding during mini-ECIRS (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Preoperative placement of nephrostomy (OR: 0.407, 95% CI: 0.143\u0026thinsp;\u0026minus;\u0026thinsp;1.159, P\u0026thinsp;=\u0026thinsp;0.092) and age (OR: 1.016, 95% CI: 0.999\u0026thinsp;\u0026minus;\u0026thinsp;1.033, P\u0026thinsp;=\u0026thinsp;0.065) were associated with less severe bleeding during mini-ECIRS.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eMultivariate logistic regression analysis including pre- and intraoperative factors predicting severe bleeding during mini-endoscopic combined intrarenal surgery.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e95% C.I. of O.R.\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eP value\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOdds ratio (O.R.)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eLower\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eUpper\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.065\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.016\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.999\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.033\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25\u0026thinsp;\u0026gt;\u0026thinsp;vs 25\u0026le;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.005\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.950\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.222\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.114\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSex\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMale vs Female\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.002\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.932\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.269\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.939\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStone diameter\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.298\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.994\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.982\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.006\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of involved calyces\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.949\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.004\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.884\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.140\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePresence of hydronephrosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.419\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.835\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.538\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.294\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePreoperative stenting\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.152\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.701\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.431\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.140\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePreoperative nephrostomy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.092\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.407\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.143\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.159\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003ePresence of intrapelvis and/or intracalyces stones\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.227\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.554\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.760\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.177\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePunctured pole\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMiddle vs Upper pole\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.598\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.872\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.524\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.451\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLower vs Upper pole\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.655\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.888\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.526\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.498\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOperative duration\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.002\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.918\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.271\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.896\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis multicenter study is the first to investigate the risk factors of severe bleeding during mini-ECIRS. We found that severe bleeding, defined as a postoperative hemoglobin drop exceeding 20%, or the need for transfusion, was independently associated with male sex, BMI\u0026thinsp;\u0026gt;\u0026thinsp;25, older age, and longer operative duration. Preoperative nephrostomy placement could mitigate bleeding risk.\u003c/p\u003e\u003cp\u003eExcessive bleeding is associated with poorer surgical outcomes in various surgeries,\u003csup\u003e6\u0026ndash;8\u003c/sup\u003e and the cutoff point is usually set at a hemoglobin drop of \u0026ge;\u0026thinsp;2 g/dL.\u003csup\u003e13\u003c/sup\u003e This study set the threshold at a 20% hemoglobin drop because the percentage value should not be more biased than the actual drop in hemoglobin levels, such as 2 g/dL. In fact, we found a significant difference in the preoperative hemoglobin levels of patients when divided by a\u0026thinsp;\u0026ge;\u0026thinsp;2 g/dL drop in hemoglobin. In this cohort, severe bleeding was associated with higher rates of septic shock and AVF formation, justifying the clinical importance of the 20% drop criterion.\u003c/p\u003e\u003cp\u003eThere is no doubt that the evidence for ECIRS is sparse, whereas many studies have found some predictors of perioperative bleeding in PCNL. Diabetes, multiple tract procedures, prolonged operative time, middle calix puncture, and the occurrence of intraoperative complications, but not surgical experience, are significantly associated with increased blood loss during PCNL.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e Meanwhile, diabetes mellitus, staghorn stones, and multiple tracts were identified as significant factors associated with severe hemorrhage post PCNL.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e Unfortunately, our database does not contain diabetes history and excludes multiple tract procedures because of the small sample size; thus, we could not directly compare our results with previous findings of PCNL. However, the findings from PCNL did not detect male sex, BMI, or age as predictors, suggesting that physicians should consider mini-ECIRS as a different surgery from PCNL for the management of blood loss complications.\u003c/p\u003e\u003cp\u003eMale sex emerged as a risk factor in this study; however, the reasons remain speculative. Potential explanations include anatomical differences in the vascular supply, variations in baseline hemoglobin levels, or differences in body composition affecting tract creation. Multiple studies have identified the male sex as a significant risk factor for increased blood loss during and after surgery. This has been observed in various surgical procedures, including pancreatectomy,\u003csup\u003e15\u003c/sup\u003e thyroidectomy,\u003csup\u003e16\u003c/sup\u003e and total knee arthroplasty.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e Although the exact reasons for this are still being investigated, factors such as increased muscle mass in males, which may lead to the reopening of coagulated vessels or dislodging sutures, have been suggested as potential contributors to this increased bleeding tendency.\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eHigher BMI was also an independent predictor of severe bleeding in this study. Notably, the success of ECIRS requires proper percutaneous puncturing, and obesity may complicate percutaneous access by increasing the tract length or requiring repeated puncture attempts, leading to greater vascular injury. Although the \u0026ldquo;high BMI and higher bleeding\u0026rdquo; phenomenon has been noted in other surgeries such as open partial nephrectomy,\u003csup\u003e18\u003c/sup\u003e some studies showed higher BMI decreased significant blood loss during coronary artery bypass graft surgeries.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e Some authors described this heterogeneity in the influence of BMI on surgical outcome as the BMI paradox\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e and hypothesized that exceeding the average BMI, irrespective of low and high, may cause surgical complications.\u003c/p\u003e\u003cp\u003eOlder age is also a predictor of an increased risk of bleeding. Age-related vascular fragility, reduced coagulation reserves, and comorbidities may contribute to this risk.\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e Surgeons should be mindful of these risks during preoperative counseling and planning. Longer operative duration was another key predictor, likely reflecting increased technical complexity, stone burden, or intraoperative bleeding, prolonging the procedure in a feedback loop.\u003c/p\u003e\u003cp\u003eOur results also demonstrate that the severe bleeding group had a significantly higher rate of residual stone formation. One possible explanation is that intraoperative bleeding may obscure the surgical field, thereby complicating complete stone clearance. Excessive bleeding can impair visibility during percutaneous access and fragmentation, leading to the incomplete retrieval of stone fragments. Moreover, the prolonged operative time associated with difficult hemostasis may increase the risk of leaving residual fragments. These findings highlight the importance of anticipating the preoperative bleeding risk and adopting strategies to minimize blood loss and improve stone-free outcomes.\u003c/p\u003e\u003cp\u003ePreoperative nephrostomy placement showed a trend toward reduced bleeding risk. This finding is particularly noteworthy, as it may represent the only modifiable preoperative intervention available to surgeons. By providing a preformed tract, a nephrostomy can reduce vascular trauma by eliminating the need for immediate tract dilation during surgery and minimizing repeated puncture attempts. Additionally, for the RIRS component, a lower intrarenal pressure can be achieved from the beginning of mini-ECIRS, which may help reduce bleeding and infection risks. Although preoperative nephrostomy can negatively affect patient\u0026rsquo;s quality of life, its selective use in high-risk patients should be considered as a strategy to improve safety and outcomes.\u003c/p\u003e\u003cp\u003eThe limitations of our study include its retrospective design, multisurgeon variability, and reliance on hemoglobin drop levels rather than direct blood loss measurements. The stone burden was assessed by maximum diameter rather than volume, although volume may better predict procedural complexity.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eSevere bleeding during mini-ECIRS is a clinically significant complication associated with increased morbidity. Identifying risk factors, such as sex, BMI, age, and operative duration, can guide individualized treatment planning. The selective use of preoperative nephrostomy may help reduce the risk of bleeding in high-risk patients. Future prospective studies are warranted to validate these findings and refine the risk prediction models.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eECIRS = endoscopic combined intrarenal surgery\u003c/p\u003e\n\u003cp\u003eRIRS = retrograde intrarenal surgery\u003c/p\u003e\n\u003cp\u003ePCNL = percutaneous nephrolithotomy\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBMI = body mass index\u003c/p\u003e\n\u003cp\u003eAVF = arteriovenous fistula\u003c/p\u003e\n\u003cp\u003eOD = odds ratio\u003c/p\u003e\n\u003cp\u003eCI = confidence interval\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and analyzed in the current study are not publicly available but can be obtained from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank Editage (http://www.editage.com) for editing and reviewing this manuscript for English language\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthorship contribution statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIto H: Protocol/project development; Data collection or management; Data analysis; Manuscript writing/editing. Fukuda T: Data collection or management. Yamamichi F: Data collection or management. Watanabe T: Data collection or management. Shibata Y: Data collection or management. Tabei T: Data analysis. Makiyama K: Protocol/project development. Inoue T: Protocol/project development. Matsuzaki J: Protocol/project development. Kobayashi K: Protocol/project development.\u003c/p\u003e\n\u003cp\u003eAll authors have read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was received for this research.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003ePerrella R, Vicentini FC, Neto MMP, et al. Endoscopic Combined Intra Renal Surgery versus Percutanous Nephrolithotomy: utcomes of a matched case-control analyis. World journal of urology 2025;43(1):275, doi:10.1007/s00345-025-05455-1\u003c/li\u003e\n\u003cli\u003eAbdullatif VA, Sur RL, Abdullatif ZA, et al. The Safety and Efficacy of Endoscopic Combined Intrarenal Surgery (ECIRS) versus Percutaneous Nephrolithotomy (PCNL): A Systematic Review and Meta-Analysis. Advances in urology 2022;2022(1716554, doi:10.1155/2022/1716554\u003c/li\u003e\n\u003cli\u003eHamamoto S, Yasui T, Okada A, et al. Endoscopic combined intrarenal surgery for large calculi: simultaneous use of flexible ureteroscopy and mini-percutaneous nephrolithotomy overcomes the disadvantageous of percutaneous nephrolithotomy monotherapy. Journal of endourology / Endourological Society 2014;28(1):28-33, doi:10.1089/end.2013.0361\u003c/li\u003e\n\u003cli\u003ePerri D, Besana U, Maltagliati M, et al. Risk of bleeding after retrograde intrarenal surgery vs miniaturised percutaneous nephrolithotomy for 10-20 mm renal stones: a not so different safety profile. BJU international 2025;135(3):497-501, doi:10.1111/bju.16585\u003c/li\u003e\n\u003cli\u003eLi Z, Wu A, Liu J, et al. Risk factors for hemorrhage requiring embolization after percutaneous nephrolithotomy: a meta-analysis. Transl Androl Urol 2020;9(2):210-217, doi:10.21037/tau.2020.01.10\u003c/li\u003e\n\u003cli\u003eKalra SK, Thilagar B, Khambaty M, et al. Post-operative Anemia After Major Surgery: a Brief Review. Current Emergency and Hospital Medicine Reports 2021;9(3):89-95, doi:10.1007/s40138-021-00232-x\u003c/li\u003e\n\u003cli\u003eJung DH, Lee HJ, Han DS, et al. Impact of perioperative hemoglobin levels on postoperative outcomes in gastric cancer surgery. Gastric Cancer 2013;16(3):377-82, doi:10.1007/s10120-012-0196-8\u003c/li\u003e\n\u003cli\u003eSalciccia S, Rosati D, Viscuso P, et al. Influence of operative time and blood loss on surgical margins and functional outcomes for laparoscopic versus robotic-assisted radical prostatectomy: a prospective analysis. Cent European J Urol 2021;74(4):503-515, doi:10.5173/ceju.2021.0177\u003c/li\u003e\n\u003cli\u003eAkman T, Binbay M, Sari E, et al. Factors affecting bleeding during percutaneous nephrolithotomy: single surgeon experience. Journal of endourology / Endourological Society 2011;25(2):327-33, doi:10.1089/end.2010.0302\u003c/li\u003e\n\u003cli\u003eKukreja R, Desai M, Patel S, et al. Factors affecting blood loss during percutaneous nephrolithotomy: prospective study. Journal of endourology / Endourological Society 2004;18(8):715-22, doi:10.1089/end.2004.18.715\u003c/li\u003e\n\u003cli\u003ePoudyal S. Current insights on haemorrhagic complications in percutaneous nephrolithotomy. Asian J Urol 2022;9(1):81-93, doi:10.1016/j.ajur.2021.05.007\u003c/li\u003e\n\u003cli\u003eIto H, Sakamaki K, Fukuda T, et al. Models to predict the surgical outcome of mini-ECIRS (endoscopic combined intrarenal surgery) for renal and/or ureteral stones. Sci Rep 2023;13(1):22848, doi:10.1038/s41598-023-50022-6\u003c/li\u003e\n\u003cli\u003ePolverino F, Di Bello F, Morra S, et al. Predictive factors of hemoglobin drop after robot-assisted radical prostatectomy: a single center prospective study. J Robot Surg 2024;18(1):337, doi:10.1007/s11701-024-02093-4\u003c/li\u003e\n\u003cli\u003eRamon de Fata F, Perez D, Resel-Folkersma L, et al. Analysis of the factors affecting blood loss in percutaneous nephrolithotomy: a registry of the Spanish Association of Urology in the supine position. Actas urologicas espanolas 2013;37(9):527-32, doi:10.1016/j.acuro.2013.05.001\u003c/li\u003e\n\u003cli\u003eMazmudar A, Vitello D, Chapman M, et al. Gender as a risk factor for adverse intraoperative and postoperative outcomes of elective pancreatectomy. J Surg Oncol 2017;115(2):131-136, doi:10.1002/jso.24488\u003c/li\u003e\n\u003cli\u003eLee D, Back K, Choe J-H, et al. Risk Factors for Post-Thyroidectomy Bleeding: an Analysis of 19,657 Cases from a Single Institution. Journal of Endocrine Surgery 2020;20(4), doi:10.16956/jes.2020.20.4.60\u003c/li\u003e\n\u003cli\u003eWu EB, Hung KC, Juang SE, et al. Are Risk Factors for Postoperative Significant Hemorrhage following Total Knee Arthroplasty Potentially Modifiable? A Retrospective Cohort Study. J Pers Med 2022;12(3), doi:10.3390/jpm12030434\u003c/li\u003e\n\u003cli\u003eKaneko G, Miyajima A, Kikuchi E, et al. The benefit of laparoscopic partial nephrectomy in high body mass index patients. Jpn J Clin Oncol 2012;42(7):619-24, doi:10.1093/jjco/hys061\u003c/li\u003e\n\u003cli\u003eNolan HR, Davenport DL, Ramaiah C. BMI Is an Independent Preoperative Predictor of Intraoperative Transfusion and Postoperative Chest-Tube Output. Int J Angiol 2013;22(1):31-6, doi:10.1055/s-0033-1333865\u003c/li\u003e\n\u003cli\u003eKott O, Golijanin B, Pereira JF, et al. The BMI Paradox and Robotic Assisted Partial Nephrectomy. Front Surg 2019;6(74, doi:10.3389/fsurg.2019.00074\u003c/li\u003e\n\u003cli\u003eClegg A, Young J, Iliffe S, et al. Frailty in elderly people. Lancet 2013;381(9868):752-62, doi:10.1016/S0140-6736(12)62167-9\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"mini-endoscopic combined intrarenal surgery, retrograde intrarenal surgery, lithotripsy, bleeding, blood transfusion","lastPublishedDoi":"10.21203/rs.3.rs-7958967/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7958967/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eMini-endoscopic combined intrarenal surgery (ECIRS) effectively treats renal and ureteral stones over percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) alone. However, factors influencing bleeding remain poorly understood. To mitigate bleeding during mini-ECIRS, we aimed to identify the factors associated with severe bleeding.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eClinical data from consecutive patients who underwent mini-ECIRS for renal and/or ureteral stones between 2015 and 2021 at three high-volume centers in Japan were analyzed. The inclusion criterion was mini-ECIRS with the modified Valdivia position. The primary outcome was the percentage of serum hemoglobin drop on postoperative day 1. Severe bleeding was defined as a\u0026thinsp;\u0026ge;\u0026thinsp;20% drop in hemoglobin or need for blood transfusion. Logistic regression models were used to identify the predictors of severe bleeding.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eAmong 1333 patients, the mean hemoglobin drop was 9.6\u0026thinsp;\u0026plusmn;\u0026thinsp;7.4%, and the transfusion rate was 0.5%. Severe bleeding occurred in 13.1% of the cases. Patients with severe bleeding had significantly higher residual stone rates (P\u0026thinsp;=\u0026thinsp;0.005) and longer operative time (P\u0026thinsp;=\u0026thinsp;0.005) than those without severe bleeding. Septic shock and arteriovenous fistulas (AVF) were also more frequent in the severe bleeding group (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Multivariate analysis identified that male sex (odds ratio [OR]: 1.904, 95% confidence interval [CI]: 1.263\u0026ndash;2.870, P\u0026thinsp;=\u0026thinsp;0.002), body mass index\u0026thinsp;\u0026gt;\u0026thinsp;25 (OR: 1.885, 95% CI: 1.192\u0026ndash;2.982, P\u0026thinsp;=\u0026thinsp;0.007), and older age (OR: 1.017, 95% CI: 1.000\u0026ndash;1.033, P\u0026thinsp;=\u0026thinsp;0.047) were independent preoperative predictors of severe bleeding. Preoperative nephrostomy placement showed a trend toward reduced bleeding risk.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eSevere bleeding during mini-ECIRS was associated with poorer surgical outcomes, including higher residual stone rates and an increased risk of septic shock and AVF. Male sex, obesity, older age, and longer operative time were the independent predictors. Preoperative nephrostomy may help reduce bleeding risk, supporting its selective use in high-risk patients to improve safety and stone-free outcomes.\u003c/p\u003e","manuscriptTitle":"Clinical predictors of blood loss during mini-endoscopic combined intrarenal surgery","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-13 08:16:14","doi":"10.21203/rs.3.rs-7958967/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4ab17ee7-ba0a-45d3-97ab-c704fedf51e1","owner":[],"postedDate":"November 13th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-23T05:09:46+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-13 08:16:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7958967","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7958967","identity":"rs-7958967","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}