Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study

Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study | 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 Article Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study Koei Torii, Shuzo Hamamoto, Kazumi Taguchi, Shinsuke Okada, Takaaki Inoue, and 7 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4161517/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 25 Jul, 2024 Read the published version in Scientific Reports → Version 1 posted 11 You are reading this latest preprint version Abstract Management of large pediatric kidney calculi (PKC) is challenging. This study aimed to evaluate the efficacy and safety of miniature endoscopic combined intrarenal surgery (mini-ECIRS) for PKC. We retrospectively analyzed mini-ECIRS in 16 pediatric patients undergoing kidney stone treatment between November 2014 and October 2023 to determine its safety, efficacy, and associated outcomes. The median age was 50.50 (interquartile range: 36.75, 84.75) months, and the mean stone size was 21.63 ± 11.65 mm. The stone-free rate was 81.25%. The median decrease in hemoglobin level on the day after surgery was 1.10 (0.80, 1.55), and no patient required a blood transfusion. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Postoperative complications included fever in two patients and difficulty in removing the ureteral stent in one patient. In this cohort, five patients underwent pre-stenting under general anesthesia before mini-ECIRS. Age was significantly lower in the pre-stenting group than in the non-pre-stenting (P < 0.01); however, there were no significant differences in operative time, stone-free rate, total number of general anesthesia procedures, hemoglobin loss, or postoperative hospital stay between the groups. Mini-ECIRS was found to be a safe and efficient treatment method with a high stone removal rate in pediatric patients. Health sciences/Urology Health sciences/Urology/Paediatric urology pediatrics kidney calculi kidney miniature endoscopic combined intrarenal surgery Figures Figure 1 Introduction Pediatric patients with urinary calculi represent 2–4.3% of all patients with urinary calculi [ 1 ]. Surgical management is needed for pediatric kidney calculi (PKC) that cannot pass spontaneously; however, its strategy is controversial owing to the diverse success rates and postoperative complications, such as the need for transfusion and decrease in renal function. In recent years, as treatment equipment has become more compact and less invasive, treatment has been increasingly used for adult stone cases, and guidelines have been developed accordingly [ 2 ]. In the treatment of children, it is necessary to adjust for physical and physiological differences with adults, and many innovations are required owing to the limitations of available instruments and catheters, the need for anesthesia, and other factors. In addition, repeated therapeutic interventions owing to poor crushing of the calculi not only waste time during the child's growth period, but may also have a negative impact on the psychological state of the child and their parents, making high crushing efficiency even more important [ 3 ]. According to the pediatric guidelines, the primary surgical treatment for PKC includes extracorporeal shock wave lithotripsy (ESWL), retrograde intrarenal surgery (RIRS), and percutaneous nephrolithotomy (PCNL) [ 4 ]. PCNL is recommended for PKC ≥ 20 mm in size within the renal pelvis; however, complications have been reported, which include bleeding, postoperative fever or infection, and persistent urinary leakage [ 5 ]. These complications have also been reported in adult cases. PCNL is associated with serious complications including extravasation and the need for transfusion [ 6 ]. Endoscopic surgery has been developed to overcome these limitations. Minimally invasive PCNL (mini-PCNL) was introduced to reduce complications associated with intraoperative bleeding using a thin PCNL tract of < 20 French. This technique could contribute to reducing procedure-related morbidity [ 7 ]; however, low therapeutic efficacy may be a serious problem for large PKC [ 8 ]. Endoscopic combined intrarenal surgery (ECIRS) with RIRS and PCNL was developed as a single-step management method for adult renal calculi in 2008 [ 9 ]. ECIRS has been indicated as an innovative and safe alternative to PCNL to achieve a high stone-free rate (SFR) [ 10 , 11 ]. However, there have been no coherent reports on ECIRS for large PKC; hence, this is the first study to report the efficacy and safety of minimally invasive ECIRS (mini-ECIRS) in the management of PKC. Methods Patient population With approval from the Institutional Review Board of Nagoya City University Graduate School of Medicine (60-19-0083), data from 16 patients who underwent ECIRS for kidney calculi at the Department of Nephro-urology of Nagoya City University Hospital between November 2014 and October 2023 were collected and retrospectively reviewed. Informed consent was obtained from parents or legal guardians of all participants and all methods were performed in accordance with the Declaration of Helsinki (2013 revision). In addition, informed consent was obtained from parents or legal guardians of all participants for publication of identifying information or images in an online open-access publication. The pediatric patients were aged 0–15 years with kidney calculi for whom surgical treatment was indicated. Data collection Medical histories, including congenital diseases, clinical examinations, and imaging data, were collected retrospectively. Blood counts and serum biochemical tests were performed in all patients. Radiological studies included urinary tract ultrasound, plain abdominal radiography (KUB), and non-contrast computed tomography (NCCT) studies when indicated. The primary endpoint was the SFR, which was defined as no residual stones or residual stones < 4 mm within three months after treatment evaluated using KUB or NCCT studies. All patients were evaluated for ureteral injury and intraoperative complications according to the postureteroscopic lesion scale [ 12 ] and for postoperative complications according to the Common Terminology Criteria for Adverse Events version 5.0 [ 13 ]. Secondary outcomes were operative time, hemoglobin (Hb) loss, postoperative hospital stay, and the total number of treatments requiring general anesthesia. Surgical technique Within one month before mini-ECIRS, pre-stenting was performed with patients under general anesthesia. The determination for the need of pre-stenting was based on the surgeon’s opinion. Antibiotics were changed on the basis of preoperative urine cultures. Mini-ECIRS was performed with patients under general anesthesia in the prone split-leg (PSL) or modified supine Valdivia (MSV) position, as previously reported [ 6 , 14 , 15 ]. Briefly, the PSL position was selected owing to the wide space of renal puncture; however, in cases of congenital malformations or when upper renal puncture was preferred, mini-ECIRS was performed in the MSV position (Fig. 1 ). A ureteral access sheath (UAS) was placed in the ureter after the retrograde ureterography, and a flexible ureteroscope (Flex-X2®, Karl Storz, Tuttlingen, Germany) was inserted through the UAS to create a hydronephrosis. Renal puncture was performed using a 21-gauge needle under combination with fluoroscopy and wideband Doppler ultrasonography. The needle entry site was monitored under direct vision as much as possible and renal puncture was repeated until accurate piercing into papilla was successfully achieved, and a mini-PCNL tract (ClearPetra®ฏ, Well Lead, MIP S®, MIP M®, Karl Storz) was placed as a working access. Following creation of the mini-PCNL tract, RIRS and mini-PCNL were performed. For stone fragmentation, a 200-µm holmium: YAG laser fiber was used retrogradely with a flexible ureteroscope, and a lithoclast lithotripsy (Boston Scientific Japan, Tokyo, Japan) or a holmium: YAG laser was used as mini-PCNL device. At the end of the procedure, a nephrostomy tube or ureteral stent was placed if necessary. The ureteral stent was threaded together with an indwelling urethral catheter and removed during hospitalization or considered for removal with patients under general anesthesia on readmission. If a nephrostomy tube was present, it was removed during hospitalization. Urinary catheters were usually removed the day after surgery. Statistical analysis All data were analyzed using the EZR software for R [ 16 ]. Quantitative variables were expressed as mean ± standard deviation or median (interquartile range) depending on the distribution pattern. Categorical data were expressed as numbers (percentages). The Mann–Whitney U test and Fisher's exact test were used to identify differences between groups. Statistical significance was set at P < 0.05. Results Patient characteristics and surgical outcomes The demographics, stone compositions, and preoperative, intraoperative, and postoperative findings are summarized in Table 1 and Table 2 . The median age of the patients was 50.50 (36.75, 84.75) months. Patient comorbidities included seven cases of cystinuria, one hyperoxaluria, two severe motor and intellectual disabilities, one type 1 renal tubular acidosis, one renal hypouricemia, one post-pyeloplasty, and one cerebral palsy. The mean stone length diameter was 21.63 ± 11.65 mm. Pre-stenting was performed in five cases (31%). The PSL position was used in 11 cases (69%) and the MSV position was used in five cases (31%). Thirteen patients (81%) did not undergo postoperative nephrostomy. Of the 15 patients who underwent postoperative ureteral stent placement, 11 underwent stent removal along with indwelling urethral catheter placement during hospitalization. The mean operative time for mini-ECIRS was 105.25 ± 36.29 min. Median Hb loss was 1.10 (0.80, 1.55) g/dL, and none of the patients required blood transfusions in the perioperative period. The median postoperative hospital stay was 4.50 (4.00, 6.25) days. Table 1 Patient demographics and stone characteristics *Quantitative variables are presented as mean (standard deviation) or median (25% interquartile range, 75% interquartile range). Categorical data are presented as numbers (%). Patient demographics and stone characteristics Number of procedures 16 Age (months) 50.50 (36.75, 84.75) Sex (%) Male 13 (81) Stone laterality (%) Left 11 (69) Maximum diameter of the stones (mm) 21.63 (11.65) Computed tomography value (Hounsfield units) 1139.50 (926.50, 1646.00) Staghorn (%) 9 (56) Comorbidities (%) Cystinuria 7 (43) Hyperoxaluria 1 (6) Severe motor and intellectual disabilities 2 (12) Type 1 renal tubular acidosis 1 (6) Renal hypouricemia 1 (6) Post-pyeloplasty 1 (6) Cerebral palsy 1 (6) Table 2 Perioperative findings *Quantitative variables are presented as mean (standard deviation) or median (25% interquartile range, 75% interquartile range). Categorical data are presented as numbers (%). CTCAE, Common Terminology Criteria for Adverse Events; Fr, French Perioperative findings Pre-stenting (%) 5 (31) Patient positioning (%) Prone split-leg 11 (69) Modified spine Valdivia 5 (31) Operative time (min) 105.25 (36.29) Tract size (%) 12-Fr 6 (37) 16-Fr 2 (12) 17.5-Fr 8 (49) Size of ureteral access sheath (%) Sheathless 2 (12) 11.5-Fr 13 (81) 14-Fr 1 (6) Ureteral stent placement (%) 15 (94) Tubeless after surgery (%) 13 (81) Stone composition (%) Calcium stone 5 (31) Cystine 7 (43) Struvite 3 (19) Sodium acid urate 1 (6) Stone-free rate (%) 13 (81) Hemoglobin loss (g/dL) 1.10 (0.80, 1.55) Postoperative hospital stay (days) 4.50 (4.00,6.25) Additional surgical intervention (%) 3 (19) General anesthesia (number of procedures) 2.00 (2.00, 2.00) Intraoperative complication (%) Ureteral injury (postureteroscopic lesion scale grade 1) 1 (6) Postoperative complication (CTCAE version 5.0 ≥ Grade2) (%) Fever 2 (12) Surgical and medical procedures (Difficulty in stent removal) 1 (6) The SFR was 81.25%. Of the patients with clinically significant stones, one underwent ECIRS again, and two underwent RIRS as ancillary treatment. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Regarding intraoperative complications, there was one case of ureteral injury (Grade 1). In one case (6%), the ureteral stent was removed with the patient under general anesthesia because of difficulties in removing the ureteral stent (≥ Grade 2). Two patients (12%) developed postoperative fever (≥ Grade 2) and were immediately administered antibiotics. Sub analysis of the efficacy of pre-stenting The efficacy of pre-stenting was evaluated by comparing surgical outcomes between the pre-stenting and non-pre-stenting groups (Table 3 ). The median ages were 33.00 (9.00, 38.00) months in the pre-stenting group and 65.00 (50.50, 106.50) months in the non-pre-stenting group, which was significantly younger (P < 0.01). Stone sizes and demographics for each group, as well as preoperative, intraoperative, and postoperative findings, and stone components for the patients were similar between the two groups. There were no significant differences in operative time, SFR, total number of general anesthesia procedures, Hb loss, or postoperative hospital stay between the two groups. The incidence of postoperative fever in the pre-stenting group was as high as 20% compared with 9% in the non-pre-stenting group; however, the difference was not statistically significant (P = 1.00). Table 3 Comparison of preoperative patient characteristics, intraoperative variables, and postoperative outcomes in the pre-stenting and non-pre-stenting groups*Quantitative variables are presented as mean (standard deviation) or median (25% interquartile range, 75% interquartile range). Categorical data are presented as numbers (%). Pre-stenting group, n = 5 Non-pre-stenting group, n = 11 P-value Age (months) 33.00 (9.00, 38.00) 65.00 (50.50, 106.50) < 0.01 Sex (%) 0.51 Male 5 (100) 8 (73) Female 0 (0) 3 (27) Stone laterality (%) 1.00 Right 2 (40) 3 (27) Left 3 (60) 8 (73) Maximum diameter of the stones (mm) 11.00 (10.00, 24.00) 24.00 (13.00, 29.50) 0.23 Computed tomography value (Hounsfield units) 1297.00 (932.00, 1731.00) 1020.00 (870.50, 1568.50) 0.51 Staghorn (%) 3 (60) 6 (55) 1.00 Patient positioning (%) 1.00 Prone split-leg 3 (50) 8 (73) Modified spine Valdivia 2 (50) 3 (27) Operative time (min) 98.00 (83.00, 140.00) 100 (82.00, 123.50) 0.91 General anesthesia (number of procedures) 2.00 (2.00, 2.00) 2.00 (1.25, 2.00) 0.09 Stone-free rate (%) 5 (100) 8 (73) 0.51 Hemoglobin loss (g/dL) 0.80 (0.30, 1.10) 1.35 (0.80, 1.60) 0.12 Postoperative hospital stay (days) 5.00 (5.00, 6.00) 4.00 (4.00, 6.00) 0.32 Fever (≥ Grade 2) (%) 1 (20) 1 (9) 1.00 Discussion To our knowledge, this is the first study to evaluate the efficacy and safety of mini-ECIRS for PKC. This retrospective study revealed that this procedure contributed to the achievement of a high SFR within three general anesthesia procedures. Furthermore, our results suggest that pre-stenting may not be necessary for pediatric mini-ECIRSs. The surgical treatment of large renal stones requires less invasiveness and high efficacy. As childhood is the most important stage of the human life cycle, health status during this period has an extremely substantial impact on later life. Therefore, in the management of PKC, it is important to avoid long-term effects on renal function and to minimize the number of treatment sessions, taking into consideration their psychological impacts on the patients and their families. ESWL and RIRS are minimally invasive therapies; however, they have the disadvantages of requiring multiple treatments for large PKC and an increased risk of recurrence with fine residual stone fragments [ 17 ]. Furthermore, ESWL for PKC may be associated with a high risk of developing hypertension in adolescence and later in life [ 18 ]. On the other hand, standard PCNL for PKC using an adult-sized device achieved a high postoperative SFR (47–90%) [ 19 ]; however, it contributed to a higher incidence of blood transfusion [ 20 ], which led to the potential risk of renal damage. Mini-PCNL, which uses a thinner device in adults, has emerged as a countermeasure to bleeding. This is thought to reduce damage to the renal parenchyma and decrease postoperative complications, while maintaining therapeutic efficacy. Mini-PCNL has also been performed in children, wherein Brodie et al. [ 21 ] reported a high SFR and reduced complications. However, even with the use of thin tracts, continued attention to renal parenchymal injury, hemorrhage, and multi-organ damage remains a challenge. Another challenge was approaching the stones in the renal calyces that could not be reached using PCNL. Therefore, mini-ECIRS, which combines RIRS and mini-PCNL, has become a focus of attention. ECIRS was first developed for adult renal calculi by Scoffone et al. in 2008 [ 9 ], and its indications have been expanding, especially in Europe and Asia. According to a meta-analysis, ECIRS could achieve a higher one-step SFR, lower possibility for ancillary treatments, and lower complication rate than standard PCNL [ 11 ]. The simultaneous use of antegrade and retrograde irrigation is a characteristic feature of the ECIRS. It allows good visibility and easy washout of fragments through the PCNL tract [ 22 ]. Furthermore, it contributes to the ureteroscopic-assisted puncture [ 23 ] and “Pass the ball” technique [ 24 ], resulting in good surgical outcomes. In this study, the initial SFR was 81.25%, and three patients required ancillary treatment. The SFR of mini-PCNL for PKC has been reported to be 84–96% [ 7 , 25 ]. Our data is slightly inferior to these previous data; however, 62% of stroke cases were included in this study. Our data revealed that no patients had perioperative bleeding-related complications, including transfusion, and the median Hb loss was 1.10 g/dL. Previous data demonstrated that the incidence of blood transfusion after mini-PCNL for PKC was 2.2–6.6% [ 7 , 25 ]. Our technique, including the use of wide Doppler ultrasound and ureteroscopic-assisted puncture, led to precise renal papilla puncture, resulting in results superior to those of previous reports. Additionally, although there were no cases of sepsis, the incidence of postoperative fever (≥ Grade 2) was 12%. According to adult data, the incidence of postoperative fever in mini-ECIRS was reported to be 10–23% [ 26 ], and this study found a comparable incidence in children. Bilateral irrigation may contribute to an excessive increase in intrarenal pelvic pressure, which is considered an important factor in postoperative sepsis. Since urinary tract infections caused by PCNL have been associated with decreased postoperative renal function [ 27 ], attention must be paid to controlling perioperative infections in ECIRS for PKC. One of the disadvantages of mini-ECIRS is that it requires a UAS for retrograde access. Since the pediatric ureteral lumen is narrower than that in adults, the UAS should be as thin as possible. To overcome this drawback, pre-stenting has been used in children to facilitate a passive ureter [ 28 ]. However, the issue of whether pre-stenting is performed in pediatric patients has been controversial. Hubert and Palmer [ 29 ] evaluated the role of pre-stenting in the pediatric population, reducing the need for active dilation during UAS insertion. In contrast, Mehmet et al. [ 30 ] found that pre-stenting in children requires general anesthesia, hospitalization, and a higher risk of radiation exposure, which are associated with additional costs. Prolonged ureteral stenting may be associated with increased risk of postoperative urinary infections or ureteral stent obstruction. In this study, we compared surgical outcomes between the pre-stenting and non-pre-stenting groups. Regarding the bias of differences in age, no significant differences were found in the surgical outcomes, including the number of general anesthesia procedures, SFR, and incidence of postoperative fever. Although the safety of anesthesia has improved dramatically since the past, it is still better to reduce the number of anesthesia procedures, and it is preferable to complete the treatment in as few procedures as possible. In the non-pre-stenting group, the total number of general anesthesia procedures was one in three cases, and in the other cases, the treatment was completed in two procedures. From this perspective, non-pre-stenting may be an option for pediatric patients with ECIRS. An important limitation of this study was its retrospective design. The lack of a prospectively assigned control group creates the disadvantage of a selection bias. Additionally, the small sample size may have reduced the study’s power. The observation period was also short; thus, long-term follow-up is necessary for pediatric patients in case of recurrence. Despite these limitations, our study provided unique information regarding pediatric ECIRS. In particular, we believe that we have provided information that allows for appropriate selection with respect to pre-stenting and patient positioning. Conclusions This is the first study to describe the efficacy and safety of mini-ECIRS in PKC. Mini-ECIRS could contribute to achieving a high SFR for PKC and a low incidence of bleeding-related complications. Since general anesthesia is required for pre-stenting in pediatric patients, preoperative stent placement should be carefully considered. Declarations Competing interests The authors declare no competing interests. Funding This study did not receive external funding. Author Contribution K. Torii: Data analysis, and manuscript writing and editingS. Hamamoto: Project conception and design, and manuscript reviewK. Taguchi: Project development, data collection, and manuscript editingS. Okada: Project conception and manuscript editingT. Inoue: Project conception and manuscript editingM. Isogai: Data collectionK. Kawase: Data collectionT. Sugino: Project development and data collectionR. Unno: Project development and data collectionT. Kato: Data collection and data managementA. Okada: Project development, data collection, and manuscript editingT. Yasui: Manuscript review and editing Acknowledgement The authors would like to thank Editage for the English language review. We also thank the doctors of the NCU Hospital who participated in this study. Data Availability The data presented in this study are available upon reasonable request from the corresponding author. References Erdenetsesteg, G., Manohar, T., Singh, H., Desai, M.R. Endourologic management of pediatric urolithiasis: proposed clinical guidelines. J Endourol. 20, 737–748 (2006). De Dominicis, M., Matarazzo, E., Capozza, N., Collura, G., Caione, P. Retrograde ureteroscopy for distal ureteric stone removal in children. BJU Int. 95, 1049–1052 (2005). Oral, İ. et al. Our experience with percutaneous nephrolithotomy in pediatric renal stone disease. Turk J Urol. 39, 35–38 (2013). Radmayr, C. et al. EAU guidelines on Pediatric Urology. European Society for Pediatric Urology. 77–85 (2023). Ozden, E., Mercimek, M.N., Yakupoǧlu, Y.K., Ozkaya, O., Sarikaya, S. 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Cite Share Download PDF Status: Published Journal Publication published 25 Jul, 2024 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 24 Jun, 2024 Reviews received at journal 12 Jun, 2024 Reviews received at journal 28 May, 2024 Reviewers agreed at journal 23 May, 2024 Reviewers agreed at journal 20 May, 2024 Reviewers agreed at journal 20 May, 2024 Reviewers invited by journal 20 May, 2024 Editor assigned by journal 20 May, 2024 Editor invited by journal 23 Apr, 2024 Submission checks completed at journal 23 Apr, 2024 First submitted to journal 25 Mar, 2024 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-4161517","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":295440932,"identity":"f9321ddb-219e-45f0-a06c-30bb9448f1d9","order_by":0,"name":"Koei Torii","email":"","orcid":"","institution":"Nagoya City University Graduate School of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Koei","middleName":"","lastName":"Torii","suffix":""},{"id":295440933,"identity":"5bff9a27-48b8-4a81-8829-3d61b8a7601b","order_by":1,"name":"Shuzo 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Center","correspondingAuthor":false,"prefix":"","firstName":"Kazumi","middleName":"","lastName":"Taguchi","suffix":""},{"id":295440935,"identity":"76596b6b-04b0-439a-8573-08939c4faad0","order_by":3,"name":"Shinsuke Okada","email":"","orcid":"","institution":"Gyotoku General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shinsuke","middleName":"","lastName":"Okada","suffix":""},{"id":295440936,"identity":"daa81f94-a6e7-4ecc-978b-f36f8e018d63","order_by":4,"name":"Takaaki Inoue","email":"","orcid":"","institution":"Hara Genitourinary Hospital","correspondingAuthor":false,"prefix":"","firstName":"Takaaki","middleName":"","lastName":"Inoue","suffix":""},{"id":295440937,"identity":"33f14752-026f-48dc-a595-5ebd4e5af38e","order_by":5,"name":"Masahiko Isogai","email":"","orcid":"","institution":"Nagoya City University Graduate School of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Masahiko","middleName":"","lastName":"Isogai","suffix":""},{"id":295440938,"identity":"152c0167-ac65-4788-9756-7248b1c824ac","order_by":6,"name":"Kengo Kawase","email":"","orcid":"","institution":"Nagoya City University Graduate School of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Kengo","middleName":"","lastName":"Kawase","suffix":""},{"id":295440939,"identity":"281c2d33-a61b-429e-bf9f-64d7d1ada842","order_by":7,"name":"Teruaki Sugino","email":"","orcid":"","institution":"Nagoya City University East Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Teruaki","middleName":"","lastName":"Sugino","suffix":""},{"id":295440940,"identity":"2454b312-b139-4928-99ca-0582cd125d11","order_by":8,"name":"Rei Unno","email":"","orcid":"","institution":"Nagoya City University Graduate School of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Rei","middleName":"","lastName":"Unno","suffix":""},{"id":295440941,"identity":"6cb7e47c-a367-41e6-bafa-0d9ddbbe42d3","order_by":9,"name":"Taiki Kato","email":"","orcid":"","institution":"Nagoya City University East Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Taiki","middleName":"","lastName":"Kato","suffix":""},{"id":295440942,"identity":"9f6944f1-273a-4470-b54e-8e71c3d7bba0","order_by":10,"name":"Atsushi Okada","email":"","orcid":"","institution":"Nagoya City University Graduate School of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Atsushi","middleName":"","lastName":"Okada","suffix":""},{"id":295440943,"identity":"d48c73ed-e490-4caa-8c9b-924f0067da76","order_by":11,"name":"Takahiro Yasui","email":"","orcid":"","institution":"Nagoya City University Graduate School of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Takahiro","middleName":"","lastName":"Yasui","suffix":""}],"badges":[],"createdAt":"2024-03-25 07:48:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4161517/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4161517/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-024-68258-1","type":"published","date":"2024-07-25T16:16:54+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":55539078,"identity":"cc6ad1d9-926d-4e2d-88c3-9efbce0b2f4f","added_by":"auto","created_at":"2024-04-29 16:54:27","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":518076,"visible":true,"origin":"","legend":"\u003cp\u003eSurgical position during mini-endoscopic combined intrarenal surgery.\u003c/p\u003e","description":"","filename":"F1.png","url":"https://assets-eu.researchsquare.com/files/rs-4161517/v1/9193358e23818c4f4fc0fb35.png"},{"id":61596531,"identity":"7bb9cfac-a53a-4bde-a39d-ec4e20e8468d","added_by":"auto","created_at":"2024-08-01 17:28:20","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1060659,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4161517/v1/ddcefd74-e7c6-4435-9917-2c2dc74526dd.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePediatric patients with urinary calculi represent 2\u0026ndash;4.3% of all patients with urinary calculi [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Surgical management is needed for pediatric kidney calculi (PKC) that cannot pass spontaneously; however, its strategy is controversial owing to the diverse success rates and postoperative complications, such as the need for transfusion and decrease in renal function. In recent years, as treatment equipment has become more compact and less invasive, treatment has been increasingly used for adult stone cases, and guidelines have been developed accordingly [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn the treatment of children, it is necessary to adjust for physical and physiological differences with adults, and many innovations are required owing to the limitations of available instruments and catheters, the need for anesthesia, and other factors. In addition, repeated therapeutic interventions owing to poor crushing of the calculi not only waste time during the child's growth period, but may also have a negative impact on the psychological state of the child and their parents, making high crushing efficiency even more important [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAccording to the pediatric guidelines, the primary surgical treatment for PKC includes extracorporeal shock wave lithotripsy (ESWL), retrograde intrarenal surgery (RIRS), and percutaneous nephrolithotomy (PCNL) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. PCNL is recommended for PKC\u0026thinsp;\u0026ge;\u0026thinsp;20 mm in size within the renal pelvis; however, complications have been reported, which include bleeding, postoperative fever or infection, and persistent urinary leakage [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. These complications have also been reported in adult cases. PCNL is associated with serious complications including extravasation and the need for transfusion [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Endoscopic surgery has been developed to overcome these limitations.\u003c/p\u003e \u003cp\u003eMinimally invasive PCNL (mini-PCNL) was introduced to reduce complications associated with intraoperative bleeding using a thin PCNL tract of \u0026lt;\u0026thinsp;20 French. This technique could contribute to reducing procedure-related morbidity [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]; however, low therapeutic efficacy may be a serious problem for large PKC [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Endoscopic combined intrarenal surgery (ECIRS) with RIRS and PCNL was developed as a single-step management method for adult renal calculi in 2008 [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. ECIRS has been indicated as an innovative and safe alternative to PCNL to achieve a high stone-free rate (SFR) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. However, there have been no coherent reports on ECIRS for large PKC; hence, this is the first study to report the efficacy and safety of minimally invasive ECIRS (mini-ECIRS) in the management of PKC.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatient population\u003c/h2\u003e \u003cp\u003e With approval from the Institutional Review Board of Nagoya City University Graduate School of Medicine (60-19-0083), data from 16 patients who underwent ECIRS for kidney calculi at the Department of Nephro-urology of Nagoya City University Hospital between November 2014 and October 2023 were collected and retrospectively reviewed. Informed consent was obtained from parents or legal guardians of all participants and all methods were performed in accordance with the Declaration of Helsinki (2013 revision). In addition, informed consent was obtained from parents or legal guardians of all participants for publication of identifying information or images in an online open-access publication. The pediatric patients were aged 0\u0026ndash;15 years with kidney calculi for whom surgical treatment was indicated.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eData collection\u003c/h2\u003e \u003cp\u003eMedical histories, including congenital diseases, clinical examinations, and imaging data, were collected retrospectively. Blood counts and serum biochemical tests were performed in all patients. Radiological studies included urinary tract ultrasound, plain abdominal radiography (KUB), and non-contrast computed tomography (NCCT) studies when indicated. The primary endpoint was the SFR, which was defined as no residual stones or residual stones\u0026thinsp;\u0026lt;\u0026thinsp;4 mm within three months after treatment evaluated using KUB or NCCT studies. All patients were evaluated for ureteral injury and intraoperative complications according to the postureteroscopic lesion scale [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] and for postoperative complications according to the Common Terminology Criteria for Adverse Events version 5.0 [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Secondary outcomes were operative time, hemoglobin (Hb) loss, postoperative hospital stay, and the total number of treatments requiring general anesthesia.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eSurgical technique\u003c/h2\u003e \u003cp\u003eWithin one month before mini-ECIRS, pre-stenting was performed with patients under general anesthesia. The determination for the need of pre-stenting was based on the surgeon\u0026rsquo;s opinion. Antibiotics were changed on the basis of preoperative urine cultures. Mini-ECIRS was performed with patients under general anesthesia in the prone split-leg (PSL) or modified supine Valdivia (MSV) position, as previously reported [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Briefly, the PSL position was selected owing to the wide space of renal puncture; however, in cases of congenital malformations or when upper renal puncture was preferred, mini-ECIRS was performed in the MSV position (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). A ureteral access sheath (UAS) was placed in the ureter after the retrograde ureterography, and a flexible ureteroscope (Flex-X2\u0026reg;, Karl Storz, Tuttlingen, Germany) was inserted through the UAS to create a hydronephrosis. Renal puncture was performed using a 21-gauge needle under combination with fluoroscopy and wideband Doppler ultrasonography. The needle entry site was monitored under direct vision as much as possible and renal puncture was repeated until accurate piercing into papilla was successfully achieved, and a mini-PCNL tract (ClearPetra\u0026reg;ฏ, Well Lead, MIP S\u0026reg;, MIP M\u0026reg;, Karl Storz) was placed as a working access. Following creation of the mini-PCNL tract, RIRS and mini-PCNL were performed. For stone fragmentation, a 200-\u0026micro;m holmium: YAG laser fiber was used retrogradely with a flexible ureteroscope, and a lithoclast lithotripsy (Boston Scientific Japan, Tokyo, Japan) or a holmium: YAG laser was used as mini-PCNL device. At the end of the procedure, a nephrostomy tube or ureteral stent was placed if necessary. The ureteral stent was threaded together with an indwelling urethral catheter and removed during hospitalization or considered for removal with patients under general anesthesia on readmission. If a nephrostomy tube was present, it was removed during hospitalization. Urinary catheters were usually removed the day after surgery.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eAll data were analyzed using the EZR software for R [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Quantitative variables were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation or median (interquartile range) depending on the distribution pattern. Categorical data were expressed as numbers (percentages). The Mann\u0026ndash;Whitney U test and Fisher's exact test were used to identify differences between groups. Statistical significance was set at P\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003ePatient characteristics and surgical outcomes\u003c/h2\u003e \u003cp\u003eThe demographics, stone compositions, and preoperative, intraoperative, and postoperative findings are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The median age of the patients was 50.50 (36.75, 84.75) months. Patient comorbidities included seven cases of cystinuria, one hyperoxaluria, two severe motor and intellectual disabilities, one type 1 renal tubular acidosis, one renal hypouricemia, one post-pyeloplasty, and one cerebral palsy. The mean stone length diameter was 21.63\u0026thinsp;\u0026plusmn;\u0026thinsp;11.65 mm. Pre-stenting was performed in five cases (31%). The PSL position was used in 11 cases (69%) and the MSV position was used in five cases (31%). Thirteen patients (81%) did not undergo postoperative nephrostomy. Of the 15 patients who underwent postoperative ureteral stent placement, 11 underwent stent removal along with indwelling urethral catheter placement during hospitalization. The mean operative time for mini-ECIRS was 105.25\u0026thinsp;\u0026plusmn;\u0026thinsp;36.29 min. Median Hb loss was 1.10 (0.80, 1.55) g/dL, and none of the patients required blood transfusions in the perioperative period. The median postoperative hospital stay was 4.50 (4.00, 6.25) days.\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\u003ePatient demographics and stone characteristics *Quantitative variables are presented as mean (standard deviation) or median (25% interquartile range, 75% interquartile range). Categorical data are presented as numbers (%).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePatient demographics and stone characteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of procedures\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (months)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(36.75, 84.75)\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(81)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStone laterality (%)\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeft\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(69)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaximum diameter of the stones (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(11.65)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComputed tomography value (Hounsfield units)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1139.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(926.50, 1646.00)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStaghorn (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(56)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComorbidities (%)\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystinuria\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(43)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHyperoxaluria\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSevere motor and intellectual disabilities\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eType 1\u0026nbsp;renal tubular acidosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRenal hypouricemia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePost-pyeloplasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCerebral palsy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\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\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\u003ePerioperative findings *Quantitative variables are presented as mean (standard deviation) or median (25% interquartile range, 75% interquartile range). Categorical data are presented as numbers (%). CTCAE, Common Terminology Criteria for Adverse Events; Fr, French\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePerioperative findings\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-stenting (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(31)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePatient positioning (%)\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProne split-leg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(69)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModified spine Valdivia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(31)\u003c/p\u003e \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\" colname=\"c2\"\u003e \u003cp\u003e105.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(36.29)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTract size (%)\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12-Fr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(37)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16-Fr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17.5-Fr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(49)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSize of ureteral access sheath (%)\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSheathless\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11.5-Fr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(81)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14-Fr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUreteral stent placement (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(94)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTubeless after surgery (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(81)\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\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCalcium stone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(31)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(43)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStruvite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(19)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSodium acid urate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStone-free rate (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(81)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin loss (g/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(0.80, 1.55)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative hospital stay (days)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(4.00,6.25)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdditional surgical intervention (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(19)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGeneral anesthesia (number of procedures)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(2.00, 2.00)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntraoperative complication (%)\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUreteral injury (postureteroscopic lesion scale grade 1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative complication (CTCAE version 5.0\u0026thinsp;\u0026ge;\u0026thinsp;Grade2) (%)\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFever\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurgical and medical procedures (Difficulty in stent removal)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\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\u003eThe SFR was 81.25%. Of the patients with clinically significant stones, one underwent ECIRS again, and two underwent RIRS as ancillary treatment. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Regarding intraoperative complications, there was one case of ureteral injury (Grade 1). In one case (6%), the ureteral stent was removed with the patient under general anesthesia because of difficulties in removing the ureteral stent (\u0026ge;\u0026thinsp;Grade 2). Two patients (12%) developed postoperative fever (\u0026ge;\u0026thinsp;Grade 2) and were immediately administered antibiotics.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eSub analysis of the efficacy of pre-stenting\u003c/h2\u003e \u003cp\u003eThe efficacy of pre-stenting was evaluated by comparing surgical outcomes between the pre-stenting and non-pre-stenting groups (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The median ages were 33.00 (9.00, 38.00) months in the pre-stenting group and 65.00 (50.50, 106.50) months in the non-pre-stenting group, which was significantly younger (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Stone sizes and demographics for each group, as well as preoperative, intraoperative, and postoperative findings, and stone components for the patients were similar between the two groups. There were no significant differences in operative time, SFR, total number of general anesthesia procedures, Hb loss, or postoperative hospital stay between the two groups. The incidence of postoperative fever in the pre-stenting group was as high as 20% compared with 9% in the non-pre-stenting group; however, the difference was not statistically significant (P\u0026thinsp;=\u0026thinsp;1.00).\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\u003eComparison of preoperative patient characteristics, intraoperative variables, and postoperative outcomes in the pre-stenting and non-pre-stenting groups*Quantitative variables are presented as mean (standard deviation) or median (25% interquartile range, 75% interquartile range). Categorical data are presented as numbers (%).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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=\"char\" char=\".\" 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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\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\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003ePre-stenting group, n\u0026thinsp;=\u0026thinsp;5\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eNon-pre-stenting group, n\u0026thinsp;=\u0026thinsp;11\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (months)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(9.00, 38.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e65.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(50.50, 106.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.01\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStone laterality (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeft\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(60)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMaximum diameter of the stones (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(10.00, 24.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e24.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(13.00, 29.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eComputed tomography value (Hounsfield units)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1297.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(932.00, 1731.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1020.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(870.50, 1568.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStaghorn (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(60)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePatient positioning (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProne split-leg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModified spine Valdivia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\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\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e98.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(83.00, 140.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(82.00, 123.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eGeneral anesthesia (number of procedures)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(2.00, 2.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(1.25, 2.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStone-free rate (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin loss (g/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(0.30, 1.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(0.80, 1.60)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative hospital stay (days)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(5.00, 6.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(4.00, 6.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFever (\u0026ge;\u0026thinsp;Grade 2) (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.00\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":"Discussion","content":"\u003cp\u003eTo our knowledge, this is the first study to evaluate the efficacy and safety of mini-ECIRS for PKC. This retrospective study revealed that this procedure contributed to the achievement of a high SFR within three general anesthesia procedures. Furthermore, our results suggest that pre-stenting may not be necessary for pediatric mini-ECIRSs.\u003c/p\u003e \u003cp\u003eThe surgical treatment of large renal stones requires less invasiveness and high efficacy. As childhood is the most important stage of the human life cycle, health status during this period has an extremely substantial impact on later life. Therefore, in the management of PKC, it is important to avoid long-term effects on renal function and to minimize the number of treatment sessions, taking into consideration their psychological impacts on the patients and their families. ESWL and RIRS are minimally invasive therapies; however, they have the disadvantages of requiring multiple treatments for large PKC and an increased risk of recurrence with fine residual stone fragments [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Furthermore, ESWL for PKC may be associated with a high risk of developing hypertension in adolescence and later in life [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. On the other hand, standard PCNL for PKC using an adult-sized device achieved a high postoperative SFR (47\u0026ndash;90%) [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]; however, it contributed to a higher incidence of blood transfusion [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], which led to the potential risk of renal damage. Mini-PCNL, which uses a thinner device in adults, has emerged as a countermeasure to bleeding. This is thought to reduce damage to the renal parenchyma and decrease postoperative complications, while maintaining therapeutic efficacy. Mini-PCNL has also been performed in children, wherein Brodie et al. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] reported a high SFR and reduced complications. However, even with the use of thin tracts, continued attention to renal parenchymal injury, hemorrhage, and multi-organ damage remains a challenge. Another challenge was approaching the stones in the renal calyces that could not be reached using PCNL. Therefore, mini-ECIRS, which combines RIRS and mini-PCNL, has become a focus of attention.\u003c/p\u003e \u003cp\u003eECIRS was first developed for adult renal calculi by Scoffone et al. in 2008 [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], and its indications have been expanding, especially in Europe and Asia. According to a meta-analysis, ECIRS could achieve a higher one-step SFR, lower possibility for ancillary treatments, and lower complication rate than standard PCNL [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The simultaneous use of antegrade and retrograde irrigation is a characteristic feature of the ECIRS. It allows good visibility and easy washout of fragments through the PCNL tract [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Furthermore, it contributes to the ureteroscopic-assisted puncture [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] and \u0026ldquo;Pass the ball\u0026rdquo; technique [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], resulting in good surgical outcomes. In this study, the initial SFR was 81.25%, and three patients required ancillary treatment. The SFR of mini-PCNL for PKC has been reported to be 84\u0026ndash;96% [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Our data is slightly inferior to these previous data; however, 62% of stroke cases were included in this study.\u003c/p\u003e \u003cp\u003eOur data revealed that no patients had perioperative bleeding-related complications, including transfusion, and the median Hb loss was 1.10 g/dL. Previous data demonstrated that the incidence of blood transfusion after mini-PCNL for PKC was 2.2\u0026ndash;6.6% [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Our technique, including the use of wide Doppler ultrasound and ureteroscopic-assisted puncture, led to precise renal papilla puncture, resulting in results superior to those of previous reports. Additionally, although there were no cases of sepsis, the incidence of postoperative fever (\u0026ge;\u0026thinsp;Grade 2) was 12%. According to adult data, the incidence of postoperative fever in mini-ECIRS was reported to be 10\u0026ndash;23% [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e], and this study found a comparable incidence in children. Bilateral irrigation may contribute to an excessive increase in intrarenal pelvic pressure, which is considered an important factor in postoperative sepsis. Since urinary tract infections caused by PCNL have been associated with decreased postoperative renal function [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], attention must be paid to controlling perioperative infections in ECIRS for PKC.\u003c/p\u003e \u003cp\u003eOne of the disadvantages of mini-ECIRS is that it requires a UAS for retrograde access. Since the pediatric ureteral lumen is narrower than that in adults, the UAS should be as thin as possible. To overcome this drawback, pre-stenting has been used in children to facilitate a passive ureter [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. However, the issue of whether pre-stenting is performed in pediatric patients has been controversial. Hubert and Palmer [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] evaluated the role of pre-stenting in the pediatric population, reducing the need for active dilation during UAS insertion. In contrast, Mehmet et al. [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] found that pre-stenting in children requires general anesthesia, hospitalization, and a higher risk of radiation exposure, which are associated with additional costs. Prolonged ureteral stenting may be associated with increased risk of postoperative urinary infections or ureteral stent obstruction. In this study, we compared surgical outcomes between the pre-stenting and non-pre-stenting groups. Regarding the bias of differences in age, no significant differences were found in the surgical outcomes, including the number of general anesthesia procedures, SFR, and incidence of postoperative fever. Although the safety of anesthesia has improved dramatically since the past, it is still better to reduce the number of anesthesia procedures, and it is preferable to complete the treatment in as few procedures as possible. In the non-pre-stenting group, the total number of general anesthesia procedures was one in three cases, and in the other cases, the treatment was completed in two procedures. From this perspective, non-pre-stenting may be an option for pediatric patients with ECIRS.\u003c/p\u003e \u003cp\u003eAn important limitation of this study was its retrospective design. The lack of a prospectively assigned control group creates the disadvantage of a selection bias. Additionally, the small sample size may have reduced the study\u0026rsquo;s power. The observation period was also short; thus, long-term follow-up is necessary for pediatric patients in case of recurrence. Despite these limitations, our study provided unique information regarding pediatric ECIRS. In particular, we believe that we have provided information that allows for appropriate selection with respect to pre-stenting and patient positioning.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThis is the first study to describe the efficacy and safety of mini-ECIRS in PKC. Mini-ECIRS could contribute to achieving a high SFR for PKC and a low incidence of bleeding-related complications. Since general anesthesia is required for pre-stenting in pediatric patients, preoperative stent placement should be carefully considered.\u003c/p\u003e "},{"header":"Declarations","content":" \u003cp\u003e \u003cstrong\u003eCompeting interests\u003c/strong\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis study did not receive external funding.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eK. Torii: Data analysis, and manuscript writing and editingS. Hamamoto: Project conception and design, and manuscript reviewK. Taguchi: Project development, data collection, and manuscript editingS. Okada: Project conception and manuscript editingT. Inoue: Project conception and manuscript editingM. Isogai: Data collectionK. Kawase: Data collectionT. Sugino: Project development and data collectionR. Unno: Project development and data collectionT. Kato: Data collection and data managementA. Okada: Project development, data collection, and manuscript editingT. Yasui: Manuscript review and editing\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors would like to thank Editage for the English language review. We also thank the doctors of the NCU Hospital who participated in this study.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data presented in this study are available upon reasonable request from the corresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eErdenetsesteg, G., Manohar, T., Singh, H., Desai, M.R. Endourologic management of pediatric urolithiasis: proposed clinical guidelines. J Endourol. 20, 737\u0026ndash;748 (2006).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDe Dominicis, M., Matarazzo, E., Capozza, N., Collura, G., Caione, P. Retrograde ureteroscopy for distal ureteric stone removal in children. BJU Int. 95, 1049\u0026ndash;1052 (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOral, İ. \u003cem\u003eet al.\u003c/em\u003e Our experience with percutaneous nephrolithotomy in pediatric renal stone disease. Turk J Urol. 39, 35\u0026ndash;38 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRadmayr, C. \u003cem\u003eet al.\u003c/em\u003e EAU guidelines on Pediatric Urology. European Society for Pediatric Urology. 77\u0026ndash;85 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOzden, E., Mercimek, M.N., Yakupoǧlu, Y.K., Ozkaya, O., Sarikaya, S. Modified Clavien classification in percutaneous nephrolithotomy: assessment of complications in children. J Urol. 185, 264\u0026ndash;268 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKyriazis, I., Panagopoulos, V., Kallidonis, P., \u0026Ouml;zsoy, M., Vasilas, M., Liatsikos, E. Complications in percutaneous nephrolithotomy. World J Urol. 33, 1069\u0026ndash;1077 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eResorlu, B. \u003cem\u003eet al.\u003c/em\u003e Comparison of retrograde intrarenal surgery and mini-percutaneous nephrolithotomy in children with moderate-size kidney stones: results of multi-institutional analysis. Urology. 80, 519\u0026ndash;523 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGiusti, G. \u003cem\u003eet al.\u003c/em\u003e Miniperc? No, thank you. \u003cem\u003eEur Urol.\u003c/em\u003e 51, 810-4; discussion 815 (2007).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScoffone, C.M., Cracco, C.M., Cossu, M., Grande, S., Poggio, M., Scarpa, R.M. Endoscopic combined intrarenal surgery in Galdakao-modified supine Valdivia position: a new standard for percutaneous nephrolithotomy. Eur Urol. 54, 1393\u0026ndash;1403 (2008).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHamamoto, S. \u003cem\u003eet al.\u003c/em\u003e Endoscopic combined intrarenal surgery for large calculi: simultaneous use of flexible ureteroscopy and mini-percutaneous nephrolithotomy overcomes the disadvantageous of percutaneous nephrolithotomy monotherapy. J Endourol. 28, 28\u0026ndash;33 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWidyokirono, D.R., Kloping, Y.P., Hidayatullah, F., Rahman, Z.A., Ng, A.C., Hakim, L. Endoscopic Combined Intrarenal Surgery vs Percutaneous Nephrolithotomy for Large and Complex Renal Stone: A Systematic Review and Meta-Analysis. J Endourol. 36, 865\u0026ndash;876 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTraxer, O., Thomas, A. Prospective evaluation and classification of ureteral wall injuries resulting from insertion of a ureteral access sheath during retrograde intrarenal surgery. J Urol. 189, 580\u0026ndash;584 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNational Cancer Institute, Common Terminology Criteria for Adverse Events (CTCAE) Common Terminology Criteria for Adverse Events (CTCAE) 5.0. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.meddra.org/\u003c/span\u003e\u003cspan address=\"https://www.meddra.org/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2017)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHamamoto, S. \u003cem\u003eet al.\u003c/em\u003e Efficacy of endoscopic combined intrarenal surgery in the prone split-leg position for staghorn calculi. J Endourol. 29, 19\u0026ndash;24 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTaguchi, K. \u003cem\u003eet al.\u003c/em\u003e First case report of staghorn calculi successfully removed by mini-endoscopic combined intrarenal surgery in a 2-year-old boy. Int J Urol. 22, 978\u0026ndash;980 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKanda, Y. Investigation of the freely available easy-to-use software 'EZR' for medical statistics. Bone Marrow Transplant. 48, 452\u0026ndash;458 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao, F.Z. \u003cem\u003eet al.\u003c/em\u003e Comparison of efficacy and safety of minimally invasive procedures for 10\u0026ndash;20 mm pediatric renal Stones-A bayesian network meta-analysis. J Pediatr Urol. 16, 771\u0026ndash;781 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDenburg, M.R. \u003cem\u003eet al.\u003c/em\u003e Assessing the risk of incident hypertension and chronic kidney disease after exposure to shock wave lithotripsy and ureteroscopy. Kidney Int. 89, 185\u0026ndash;192 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSamad, L., Aquil, S., Zaidi, Z. Paediatric percutaneous nephrolithotomy: setting new frontiers. BJU Int. 97, 359\u0026ndash;363 (2006).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBilen, C.Y., Ko\u0026ccedil;ak, B., Kitirci, G., Ozkaya, O., Sarikaya, S. Percutaneous nephrolithotomy in children: lessons learned in 5 years at a single institution. J Urol. 177, 1867\u0026ndash;1871 (2007).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrodie, K.E. \u003cem\u003eet al.\u003c/em\u003e Outcomes following 'mini' percutaneous nephrolithotomy for renal calculi in children. A single-centre study. J Pediatr Urol. 11, 120.e1-5 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJung, H.D. \u003cem\u003eet al.\u003c/em\u003e Real-time simultaneous endoscopic combined intrarenal surgery with intermediate-supine position: Washout mechanism and transport technique. Investig Clin Urol. 59, 348\u0026ndash;354 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTaguchi, K. \u003cem\u003eet al.\u003c/em\u003e Ureteroscopy-assisted puncture for ultrasonography-guided renal access significantly improves overall treatment outcomes in endoscopic combined intrarenal surgery. Int J Urol. 28, 913\u0026ndash;919 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAron, M. \u003cem\u003eet al.\u003c/em\u003e Multi-tract percutaneous nephrolithotomy for large complete staghorn calculi. Urol Int. 75, 327\u0026ndash;332 (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMahmoud, M.A., Shawki, A.S., Abdallah, H.M., Mostafa, D., Elawady, H., Samir, M. Use of retrograde intrarenal surgery (RIRS) compared with mini-percutaneous nephrolithotomy (mini-PCNL) in pediatric kidney stones. World J Urol. 40, 3083\u0026ndash;3089 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHamamoto, S. \u003cem\u003eet al.\u003c/em\u003e Comparison of the safety and efficacy between the prone split-leg and Galdakao-modified supine Valdivia positions during endoscopic combined intrarenal surgery: A multi-institutional analysis. Int J Urol. 28, 1129\u0026ndash;1135 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFayad, A.S. \u003cem\u003eet al.\u003c/em\u003e Effect of multiple access tracts during percutaneous nephrolithotomy on renal function: evaluation of risk factors for renal function deterioration. J Endourol. 28, 775\u0026ndash;779 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMinevich, E. \u003cem\u003eet al.\u003c/em\u003e Ureteroscopy is safe and effective in prepubertal children. \u003cem\u003eJ Urol.\u003c/em\u003e 174, 276-9; discussion 279 (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHubert, K.C., Palmer, J.S. Passive dilation by ureteral stenting before ureteroscopy: eliminating the need for active dilation. \u003cem\u003eJ Urol.\u003c/em\u003e 174, 1079-80; discussion 1080 (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGokce, M.I. \u003cem\u003eet al.\u003c/em\u003e Effect of Prestenting on Success and Complication Rates of Ureterorenoscopy in Pediatric Population. J Endourol. 30, 850\u0026ndash;855 (2016).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"pediatrics, kidney calculi, kidney, miniature endoscopic combined intrarenal surgery","lastPublishedDoi":"10.21203/rs.3.rs-4161517/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4161517/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eManagement of large pediatric kidney calculi (PKC) is challenging. This study aimed to evaluate the efficacy and safety of miniature endoscopic combined intrarenal surgery (mini-ECIRS) for PKC. We retrospectively analyzed mini-ECIRS in 16 pediatric patients undergoing kidney stone treatment between November 2014 and October 2023 to determine its safety, efficacy, and associated outcomes. The median age was 50.50 (interquartile range: 36.75, 84.75) months, and the mean stone size was 21.63\u0026thinsp;\u0026plusmn;\u0026thinsp;11.65 mm. The stone-free rate was 81.25%. The median decrease in hemoglobin level on the day after surgery was 1.10 (0.80, 1.55), and no patient required a blood transfusion. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Postoperative complications included fever in two patients and difficulty in removing the ureteral stent in one patient. In this cohort, five patients underwent pre-stenting under general anesthesia before mini-ECIRS. Age was significantly lower in the pre-stenting group than in the non-pre-stenting (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01); however, there were no significant differences in operative time, stone-free rate, total number of general anesthesia procedures, hemoglobin loss, or postoperative hospital stay between the groups. Mini-ECIRS was found to be a safe and efficient treatment method with a high stone removal rate in pediatric patients.\u003c/p\u003e","manuscriptTitle":"Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-29 16:54:22","doi":"10.21203/rs.3.rs-4161517/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-06-24T08:30:51+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-12T23:06:08+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-05-28T06:21:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"235404271922668049790065652073120191721","date":"2024-05-23T21:23:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"150729750908584562044525954653136411337","date":"2024-05-20T08:17:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"195841758890639798963315933557078288308","date":"2024-05-20T06:17:22+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-20T05:54:20+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-20T05:44:04+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-04-23T07:40:02+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-04-23T07:36:08+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-03-25T07:46:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a0b6e386-1e16-4f0e-94a8-deac0ca45c7d","owner":[],"postedDate":"April 29th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":31155646,"name":"Health sciences/Urology"},{"id":31155647,"name":"Health sciences/Urology/Paediatric urology"}],"tags":[],"updatedAt":"2024-08-01T17:12:55+00:00","versionOfRecord":{"articleIdentity":"rs-4161517","link":"https://doi.org/10.1038/s41598-024-68258-1","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2024-07-25 16:16:54","publishedOnDateReadable":"July 25th, 2024"},"versionCreatedAt":"2024-04-29 16:54:22","video":"","vorDoi":"10.1038/s41598-024-68258-1","vorDoiUrl":"https://doi.org/10.1038/s41598-024-68258-1","workflowStages":[]},"version":"v1","identity":"rs-4161517","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4161517","identity":"rs-4161517","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}