Verification of surgical factors affecting the efficiency of stone extraction using a f-URSL simulation model

Verification of surgical factors affecting the efficiency of stone extraction using a f-URSL simulation model | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Verification of surgical factors affecting the efficiency of stone extraction using a f-URSL simulation model Ryusuke Deguchi, Shimpei Yamashita, Yuya Iwahashi, Hiroki Kawabata, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3873413/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract When performing flexible ureteroscopic lithotripsy for upper urinary stones, an important treatment option is stone extraction. In this study, we aim to investigate the surgical factors affecting the efficiency of stone extraction and surgeon stress using a flexible ureteroscopic lithotripsy simulator model. This simulator-based study involved 16 participants: eight urologists and eight residents. Participants each performed two tasks eight times, with two types of ureteral access sheath (Flexor or Navigator), with or without M-arm, and with left or right kidney models. Task1 was to touch each renal calix with the ureteroscope, and Task2 was to extract stones. The recorded outcomes of this study were the number of times that the ureteroscope got stuck during insertion, the number of times a stone was dropped during removal, the number of times the basket forceps were opened and closed, and the time required to accomplish each task. The number of times that the ureteroscope got stuck was significantly higher when Navigator was used compared with Flexor overall, and for urologists and residents (all P < 0.01). The number of times a stone was dropped was significantly higher in the ipsilateral group than in the contralateral group overall ( P = 0.01), and the number of times the basket forceps were opened and closed was significantly higher in the ipsilateral group than in the contralateral group both overall and for residents (all P < 0.01). Differences in ureteral access sheath and the kidney side were surgical factors affecting the efficiency of stone extraction during flexible ureteroscopic lithotripsy with the one-surgeon basketing technique. Flexible ureteroscopic lithotripsy Stone extraction Ureteral access sheath Simulator-based study Figures Figure 1 Figure 2 Introduction Flexible ureteroscopic lithotripsy (f-URSL) has become a gold standard treatment option for upper urinary stone surgery along with shock wave lithotripsy (SWL). SWL is still the main treatment for the patients with upper urinary tract stones because it is minimally invasive and highly effective. However, there are some cases in which SWL is unsuitable, such as those with large stones, hard stones, lower pole renal stones, and impacted ureteral stones. f-URSL is recommended for these cases [ 1 – 4 ]. A major advantage of f-URSL is the ability to extract stones. ‘Basketing’ and ‘dusting’ have emerged as two main strategies for f-URSL [ 5 ], but it is unclear which strategy is superior. A recent meta-analysis concluded that the basketing group had significantly higher stone free rate and lower retreatment rate ( P = 0.01, 0.001, respectively), while the dusting group had significantly shorter operative time ( P = 0.004) [ 6 ]. There are three advantages of performing stone extractions compared with dusting. First, all stone fragments can be completely extracted. Second, it is possible to perform stone component analysis. Third, the total laser energy and thermal damage to the urothelium are lower than those by dusting [ 7 ]. Due to these advantages, we believe that stone extraction is an indispensable option during performance of f-URSL. The efficacy of the one-surgeon basketing technique has been demonstrated [ 8 , 9 ]. In this method, the surgeon handles the flexible ureteroscope with one hand and simultaneously manipulates the basket forceps with the other hand, as opposed to the conventional two- surgeon basketing technique in which two surgeons separately handle the flexible ureteroscope and basket forceps. In a simulator comparative study, Okada et al. reported that in the case of trained surgeons, the one-surgeon basketing technique took less time to extract stones than the two-surgeon basketing technique ( P = 0.049), and the basket forceps were opened and closed fewer times in surgeons overall ( P = 0.018) [ 8 ]. Although the one-surgeon basketing technique has the disadvantage of requiring technical training and being somewhat challenging for beginners, it is expected to become more widespread in the future due to the ability to extract stones more efficiently. However, there have been no reports on surgical factors affecting the efficiency of stone extraction and surgeon stress during performance of f-URSL with the one-surgeon basketing technique. In the current study, we therefore aim to investigate these surgical factors using f-URSL simulator models. Materials and Methods Experimental setting This simulator-based study aims to evaluate surgical factors affecting the efficiency of stone extraction during f-URSL with the one-surgeon basketing technique. The simulation models for f-URSL were manufactured by Cook Medical (Bloomington, IN, USA) and were a close reproduction of the anatomy of the renal collecting system ( Fig. 1 A ) . We prepared two of these simulation models each with a different type of ureteral access sheath (UAS) indwelled: Flexor™, Cook Medical, size; 10.7/12.7Fr, and Navigator™ HD, Boston Scientific, Marlborough, MA, USA, size; 11/13Fr). Artificial stones (5×5×5 mm) were placed in the upper, middle and lower renal calix and renal pelvis. The equipment used in this study was flexible ureteroscopy (URF-P7, OLYMPUS, Tokyo, Japan) under gravity irrigation and N-circle ® (Cook Medical) with and without M-arm (MC MEDICAL, Sapporo, Japan) assistance for stone extraction. Study subject and design Participating in this study were eight urologists with Japanese certification as specialist in urology and eight residents in training, who had not yet obtained this certification. Recorded participant information were the participants’ age, gender, years of experience in urology, number of operations experienced, the usual basketing technique (one-surgeon or two-surgeon), dominant hand, and which hand operated the ureteroscope. Participants performed the following tasks eight times per person, with two types of UAS, with or without M-arm, and with left or right kidney model. Task 1 was to touch the upper, middle and lower renal calyces with the ureteroscope three times each ( Fig. 1 B ) , and Task 2 was to extract one stone from each of the upper, middle and lower renal calyces and the renal pelvis with N-circle ® (Cook Medical) ( Fig. 1 C ) . Participants were instructed to remove and reinsert the ureteroscope each time the renal calix was touched or stones were extracted. The outcomes of this study were surgical technique performance and surgeon stress. Representing surgical technique performance, we recorded the number of times that the ureteroscope got stuck during insertion (No. stuck), the number of times a stone was dropped during removal (No. drop), the number of times the basket forceps were opened and closed (No. switch), and the time required to accomplish each task (Time task 1 & 2). These outcomes were measured by two observers, and if results differed, they were discussed and finalized. Participants were not informed of the purpose or outcomes of this study. At the end of each task, surgeon stress was assessed using the NASA-Task Load Index (NASA-TLX), a previously validated performance scale. [ 10 ] Statistical analyses Participant demographics were compared between the urologists and residents with Chi square tests or Mann-Whitney U tests. The outcomes of this study were compared between Navigator and Flexor, with and without M-arm, ipsilateral and contralateral kidneys to the hand operating the ureteroscope. This was done by Mann-Whitney U tests and overall results were collected, as well as those for urologists, and residents. Statistical analyses were all performed using JMP Pro 13 (SAS Institute, Cary, NC, USA) and P < 0.05 was considered statistically significant. Results Participant demographics Participant demographics was summarized in Table 1 . As expected, the urologists were significantly older and had more experience in urology and had thus experienced a higher number of URS procedures than the residents (all P < 0.01). There was no significant difference between urologists and residents in the basketing technique (one-surgeon or two-surgeon) usually performed ( P = 0.61). All participants were right handed, and the percentage of participants who handled the ureteroscope with their left hand was not significantly different between urologists and residents ( P = 0.51). Outcomes Outcomes of this study were compared for each of three surgical factors that may affect the efficiency of stone extraction. The first surgical factor was the difference in ureteral access sheaths. Comparison of outcomes between Navigator and Flexor was shown in Table 2 . No. stuck was significantly higher when Navigator was used than when Flexor was used overall, and for urologists, and residents (all P < 0.01). There were no significant differences between Navigator and Flexor in No. drop, No. switch, or Time task 1 & 2. In the comparison of NASA-TLX, only mental demand was significantly higher when Navigator was used than when Flexor was used for residents ( P = 0.04). The second surgical factor was the use or non-use of the M-arm. Outcomes were compared with and without the use of M-arm, but no significant differences were found in any of the outcomes (Table 3) . The third surgical factor was whether the kidney was ipsilateral or contralateral to the hand manipulating the ureteroscope. Comparison of outcomes between the ipsilateral and contralateral sides was shown in Table 4 . No. drop was significantly higher in the ipsilateral group than in the contralateral group overall ( P = 0.01), and No. switch was significantly higher in the ipsilateral group than in the contralateral group overall and for residents (all P < 0.01). No significant differences were shown between the ipsilateral and contralateral sides in No. stuck, Time task 1 & 2, or NASA-TLX. Discussion We used f-URSL simulator models to investigate whether three surgical factors (UAS, M-arm and kidney side) could affect the efficiency of stone extraction and surgeon stress in the one-surgeon basketing technique. The differences in UAS and the kidney side were thought to have the potential to influence the efficacy of stone extractions and surgeon stress. To our knowledge, there are few reports on surgical factors affecting the efficiency of stone extraction and surgeon stress, and the present study is the first to focus specifically on differences in UAS and the left or right sides of a kidney. UAS is commonly used to perform f-URSL for upper urinary tract stones. Advantages include safe and reproducible access to the upper urinary tract, reduction of the intrarenal pressure, and protection of the ureteroscope [ 11 , 12 ]. On the other hand, UAS insertion may increase the risk of acute ureteral injuries and long-term ureteral stricture [ 11 , 13 ]. Weighing the advantages and disadvantages, routine use of UAS is not currently recommended, but UAS is a useful instrument when used in select cases. There are many different types of UAS available on the market with different characteristics, lengths, and sizes [ 14 ], and one of these characteristics is the introducer-hub structure. The present study revealed that the number of times that the ureteroscope got stuck during insertion was significantly higher when Navigator was used compared with Flexor ( P < 0.01). In consideration of these causes, we evaluated the cross section of each UAS and found that the internal tapering structure was observed more often in Flexor than in Navigator ( Fig. 2 A and B) . In addition, Time task 2 (time required for stone extractions) tended to be shorter for urologists when Flexor was used than when Navigator was used ( P = 0.05). Also, mental demand, a sub-score of NASA-TLX, was significantly lower for residents when Flexor was used than when Navigator was used ( P = 0.04) (Table 2) . These results suggest that the differences in endoscopic insertability associated with the difference in the introducer-hub structure of UAS may affect the efficiency of stone extractions and surgeon stress. Furthermore, we suggest that this effect may be stronger because the number of times the endoscope is inserted and removed would be greater during actual surgery than during this study. A single-use basket holder, which connects the basket forceps to the ureteroscope, is useful to maintain stability of the manipulation during f-URSL with the one-surgeon basketing technique [ 8 ]. M-arm is one of the single-use basket holders available in Japan. The effect of M-arm on the efficiency of stone extraction has not been previously reported. Okada et al. reported that the use of M-arm was beneficial in smoothly facilitating device exchange, and they showed the efficacy of the one-surgeon basketing technique [ 8 ]. Unfortunately, the present study could not demonstrate the effectiveness of M-arm with respect to extraction efficiency or surgeon stress. However, there were several urologist participants in this study who were accustomed to performing f-URSL by the one-surgeon basketing technique and without using the M-arm. We speculated that they had good outcomes without the use of M-arm, which would be a factor in our inability to demonstrate the efficacy of M-arm. Another single-use basket holder is LithoVue Empower™ (Boston Scientific), which is available worldwide. Empower is connected to the handle part of the ureteroscope, allowing the surgeon to simultaneously manipulate the ureteroscope and Empower with one hand. This differs from M-arm, in which the surgeon simultaneously manipulates the ureteroscope with one hand and the basket forceps with the other hand [ 8 ]. Coordination of two-handed manipulation is needed, so M-arm-assisted stone extraction is considered to require more proficiency than by Empower. Use of Empower has been reported to significantly reduce the time required for stone extraction and the number of times the basket forceps were opened and closed compared with M-arm [ 15 ]. This report was a simulator study with participants who were nurses without f-URSL experience, and it showed the usefulness of Empower for beginners. However, there have been no reports on which basket holder (M-arm vs. Empower) is superior when used by skilled surgeons, and we look forward to further validation. The ureteroscope moves only vertically (up or down), but by adding rotational manipulation and back and forth movement, the desired movement of the ureteroscope can be achieved. Rotation of ureteroscope is performed by flexion and extension of the wrist. The wrist joint range of motion (ROM) is 68–83◦ for flexion and 57–69◦ for extension, with ROM for extension being narrower [ 16 – 18 ]. Considering the pyelocaliceal anatomy, when approaching the kidney on the ipsilateral side to the hand manipulation of the ureteroscope (e.g., the left kidney when manipulating the ureteroscope with the left hand), the manipulation is primarily an extension of the wrist. For this reason, it was thought that when approaching the ipsilateral kidney, extension movement of the wrist is the main movement, which may make manipulation more difficult due to the ROM of the wrist compared with the approach to the contralateral kidney. In the present study, No. drop and No. switch were significantly higher in the ipsilateral group than in the contralateral group overall (respectively, P = 0.01 and < 0.01) (Table 4) . Interestingly, these trends were not observed among urologists who were skilled in ureteroscopic manipulation, but were more pronounced in residents. Recently, an interesting simulator-based study using motion capture showed that ureteroscopic efficiency in f-URS was correlated with head and torso movement [ 19 ]. If sufficient ureteroscopic manipulation cannot be achieved by wrist rotation alone, elbows, shoulders, and the torso should be moved to represent them. We believe that this report is an important finding related to the results of our study. This study has several limitations. First, the simulation models used in this study might differ slightly from actual renal pelvis morphology. Second, our participants varied in the number of cases experienced and in the basketing technique they usually use. Finally, the number of stone extractions was less than actual typical f-URSL. Despite these limitations, this is thought to be the first report to identify the differences in UAS and the renal side as the surgical factors affecting the efficiency of stone extraction during f-URSL with the one-surgeon basketing technique. We hope that these new findings will be used effectively in developing a surgical strategy for f-URSL. Conclusions The differences in UAS and the kidney side were surgical factors affecting the efficiency of stone extraction during f-URSL with the one-surgeon basketing technique. Basketing is an indispensable treatment option for achieving stone-free status, and the one-surgeon basketing technique seems to be efficient. We hope that the results of this study will be used effectively in developing treatment strategies for f-URSL. Abbreviations f-URSL flexible ureteroscopic lithotripsy NASA-TLX NASA-Task Load Index No. drop the number of times the stone was dropped during removal No. stuck the number of times that the ureteroscope got stuck during insertion No. switch the number of times the basket forceps were opened and closed ROM range of motion SWL shock wave lithotripsy Declarations Conflict of interests The authors declare that there are no conflicts of interest regarding the publication of this article. Ethical approval This was a simulator-based study with no patients, so ethical approval was deemed unnecessary. Informed consent For the same reasons as for ethical approval, informed consent for patients was not obtained. Consent for publication of the study was obtained for all participants. Funding The authors did not receive support from any organization for the submitted work. Author Contribution RD: protocol/project development, data collection and management, data analysis, manuscript writing/editing and illustrations; SH: protocol/project development, data collection, data management and supervision; YI: protocol/project development; HK: protocol/project development; SM: protocol/project development; TW: protocol/project development; YK: protocol/project development and supervision; IH: supervision.All authors reviewed the manuscript. Acknowledgements This document was proofread and edited by Benjamin Phillis at the Clinical Study Support Center at Wakayama Medical University. References Lv G, Qi W, Gao H et al (2022) Safety and efficacy of extracorporeal shock wave lithotripsy vs. flexible ureteroscopy in the treatment of urinary calculi: A systematic review and meta-analysis. 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North-Holland, pp 139–183 https://doi.org/10.1016/S0166-4115(08)62386-9 Breda A, Territo A, Lopez-Martinez JM (2016) Benefits and risks of ureteral access sheaths for retrograde renal access. Curr Opin Urol 26:70–75. 10.1097/MOU.0000000000000233 Wong VK, Aminoltejari K, Almutairi K et al (2020) Controversies associated with ureteral access sheath placement during ureteroscopy. Investig Clin Urol 61:455–463. 10.4111/icu.20200278 Loftus CJ, Ganesan V, Traxer O et al (2020) Ureteral Wall Injury with Ureteral Access Sheaths: A Randomized Prospective Trial. J Endourol 34:932–936. 10.1089/end.2018.0603 Al-Qahtani SM, Letendre J, Thomas A et al (2014) Which ureteral access sheath is compatible with your flexible ureteroscope? J Endourol 28:286–290. 10.1089/end.2013.0375 Taguchi M, Kinoshita H (2023) Comparison of Empower and M-arm for One-surgeon Basketing in Ureteroscopic Lithotripsy: A Simulator Study by Non-doctors. Urology 172:44–48. 10.1016/j.urology.2022.10.025 Ryu JY, Cooney WP 3rd, Askew LJ et al (1991) Functional ranges of motion of the wrist joint. J Hand Surg Am 16:409–419. 10.1016/0363-5023(91)90006-w Aizawa J, Masuda T, Hyodo K et al (2013) Ranges of active joint motion for the shoulder, elbow, and wrist in healthy adults. Disabil Rehabil 35:1342–1349. 10.3109/09638288.2012.731133 Costa V, Ramirez O, Otero A et al (2020) Validity and reliability of inertial sensors for elbow and wrist range of motion assessment. PeerJ 8:e9687 10.7717/peerj.9687 . PMID: 32864213 Valovska MT, Gomez G, Fineman R et al (2022) Analysis of Flexible Ureteroscopic Motion and Kinematic Efficiency: A Simulation-Based Pilot Study. J Endourol 36:855–861. 10.1089/end.2021.0726 Tables Tables 1 to 4 are available in the Supplementary Files section. Additional Declarations No competing interests reported. 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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-3873413","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":267774893,"identity":"0f5d0b4b-42de-4253-a921-7fd06f4d0eb0","order_by":0,"name":"Ryusuke Deguchi","email":"","orcid":"","institution":"Wakayama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ryusuke","middleName":"","lastName":"Deguchi","suffix":""},{"id":267774894,"identity":"c3d19be0-37b4-4d0a-bb2a-d8b713646b5a","order_by":1,"name":"Shimpei Yamashita","email":"data:image/png;base64,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","orcid":"","institution":"Wakayama Medical University","correspondingAuthor":true,"prefix":"","firstName":"Shimpei","middleName":"","lastName":"Yamashita","suffix":""},{"id":267774895,"identity":"7ef0a22d-90f5-47d1-93c3-11b87f56104d","order_by":2,"name":"Yuya Iwahashi","email":"","orcid":"","institution":"Wakayama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yuya","middleName":"","lastName":"Iwahashi","suffix":""},{"id":267774896,"identity":"1fec885a-9f16-410b-a851-fc414236bbed","order_by":3,"name":"Hiroki Kawabata","email":"","orcid":"","institution":"Wakayama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Hiroki","middleName":"","lastName":"Kawabata","suffix":""},{"id":267774897,"identity":"4b7816bb-42fd-4df8-bc00-2b950c2e011f","order_by":4,"name":"Satoshi Muraoka","email":"","orcid":"","institution":"Wakayama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Satoshi","middleName":"","lastName":"Muraoka","suffix":""},{"id":267774898,"identity":"48474589-a0d8-4e21-ae84-7cd872b29a91","order_by":5,"name":"Takahito Wakamiya","email":"","orcid":"","institution":"Wakayama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Takahito","middleName":"","lastName":"Wakamiya","suffix":""},{"id":267774899,"identity":"68be551a-351b-4e1b-b7d6-3ca5c05fb047","order_by":6,"name":"Yasuo Kohjimoto","email":"","orcid":"","institution":"Wakayama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yasuo","middleName":"","lastName":"Kohjimoto","suffix":""},{"id":267774900,"identity":"65621918-9446-4f4a-8cf1-6d3863c941c5","order_by":7,"name":"Isao Hara","email":"","orcid":"","institution":"Wakayama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Isao","middleName":"","lastName":"Hara","suffix":""}],"badges":[],"createdAt":"2024-01-17 17:00:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3873413/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3873413/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":49890999,"identity":"3168f44d-663a-4aa2-b763-8d7189c7004a","added_by":"auto","created_at":"2024-01-19 20:23:56","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":399389,"visible":true,"origin":"","legend":"\u003cp\u003eStudy methods. (A) The simulator used in this study. (B) Task1: To touch the upper, middle and lower renal calyces with the endoscope three times each. (C) Task2: To extract one stone from each of the upper, middle and lower renal calyxes and the renal pelvis with a basket catheter.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-3873413/v1/cffbd03d378aedfc5fbc555b.png"},{"id":49891000,"identity":"64765050-1cb2-4c4f-bf98-abbe6cd03f5c","added_by":"auto","created_at":"2024-01-19 20:23:56","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":299817,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram and picture of access sheath cross section. (A) Navigator (B) Flexor\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-3873413/v1/feefa78c6f74d95b2ec418fb.png"},{"id":51185171,"identity":"d01968a6-c0a4-439d-9310-3b0b4ec1da25","added_by":"auto","created_at":"2024-02-15 15:50:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":913067,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3873413/v1/c6e22141-700c-4187-b118-ca6add295901.pdf"},{"id":49891618,"identity":"894743f7-2654-4d6b-9b41-b3799908356c","added_by":"auto","created_at":"2024-01-19 20:31:56","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":10930,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-3873413/v1/16352f847e6a3e87495b26c9.xlsx"},{"id":49891619,"identity":"30384c43-11ac-4e92-9edf-d9ed97bb7615","added_by":"auto","created_at":"2024-01-19 20:31:56","extension":"xlsx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":16568,"visible":true,"origin":"","legend":"","description":"","filename":"Table2.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-3873413/v1/d721d9422d49036cf631f7ca.xlsx"},{"id":49891002,"identity":"0351c200-bc25-4670-8402-8f41aaa424e7","added_by":"auto","created_at":"2024-01-19 20:23:56","extension":"xlsx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":16092,"visible":true,"origin":"","legend":"","description":"","filename":"Table3.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-3873413/v1/89fac5b85da68808169436dd.xlsx"},{"id":49891004,"identity":"95d507bf-8d17-43ec-a88e-acb668181110","added_by":"auto","created_at":"2024-01-19 20:23:56","extension":"xlsx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":16452,"visible":true,"origin":"","legend":"","description":"","filename":"Table4.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-3873413/v1/561dfec5e51edf6bd070273d.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Verification of surgical factors affecting the efficiency of stone extraction using a f-URSL simulation model","fulltext":[{"header":"Introduction","content":"\u003cp\u003eFlexible ureteroscopic lithotripsy (f-URSL) has become a gold standard treatment option for upper urinary stone surgery along with shock wave lithotripsy (SWL). SWL is still the main treatment for the patients with upper urinary tract stones because it is minimally invasive and highly effective. However, there are some cases in which SWL is unsuitable, such as those with large stones, hard stones, lower pole renal stones, and impacted ureteral stones. f-URSL is recommended for these cases [\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eA major advantage of f-URSL is the ability to extract stones. \u0026lsquo;Basketing\u0026rsquo; and \u0026lsquo;dusting\u0026rsquo; have emerged as two main strategies for f-URSL [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], but it is unclear which strategy is superior. A recent meta-analysis concluded that the basketing group had significantly higher stone free rate and lower retreatment rate (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.01, 0.001, respectively), while the dusting group had significantly shorter operative time (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.004) [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. There are three advantages of performing stone extractions compared with dusting. First, all stone fragments can be completely extracted. Second, it is possible to perform stone component analysis. Third, the total laser energy and thermal damage to the urothelium are lower than those by dusting [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Due to these advantages, we believe that stone extraction is an indispensable option during performance of f-URSL.\u003c/p\u003e \u003cp\u003eThe efficacy of the one-surgeon basketing technique has been demonstrated [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In this method, the surgeon handles the flexible ureteroscope with one hand and simultaneously manipulates the basket forceps with the other hand, as opposed to the conventional two- surgeon basketing technique in which two surgeons separately handle the flexible ureteroscope and basket forceps. In a simulator comparative study, Okada et al. reported that in the case of trained surgeons, the one-surgeon basketing technique took less time to extract stones than the two-surgeon basketing technique (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.049), and the basket forceps were opened and closed fewer times in surgeons overall (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.018) [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Although the one-surgeon basketing technique has the disadvantage of requiring technical training and being somewhat challenging for beginners, it is expected to become more widespread in the future due to the ability to extract stones more efficiently. However, there have been no reports on surgical factors affecting the efficiency of stone extraction and surgeon stress during performance of f-URSL with the one-surgeon basketing technique. In the current study, we therefore aim to investigate these surgical factors using f-URSL simulator models.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eExperimental setting\u003c/h2\u003e \u003cp\u003eThis simulator-based study aims to evaluate surgical factors affecting the efficiency of stone extraction during f-URSL with the one-surgeon basketing technique. The simulation models for f-URSL were manufactured by Cook Medical (Bloomington, IN, USA) and were a close reproduction of the anatomy of the renal collecting system \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA\u003cb\u003e)\u003c/b\u003e. We prepared two of these simulation models each with a different type of ureteral access sheath (UAS) indwelled: Flexor\u0026trade;, Cook Medical, size; 10.7/12.7Fr, and Navigator\u0026trade; HD, Boston Scientific, Marlborough, MA, USA, size; 11/13Fr). Artificial stones (5\u0026times;5\u0026times;5 mm) were placed in the upper, middle and lower renal calix and renal pelvis. The equipment used in this study was flexible ureteroscopy (URF-P7, OLYMPUS, Tokyo, Japan) under gravity irrigation and N-circle\u003csup\u003e\u0026reg;\u003c/sup\u003e (Cook Medical) with and without M-arm (MC MEDICAL, Sapporo, Japan) assistance for stone extraction.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eStudy subject and design\u003c/h2\u003e \u003cp\u003eParticipating in this study were eight urologists with Japanese certification as specialist in urology and eight residents in training, who had not yet obtained this certification. Recorded participant information were the participants\u0026rsquo; age, gender, years of experience in urology, number of operations experienced, the usual basketing technique (one-surgeon or two-surgeon), dominant hand, and which hand operated the ureteroscope. Participants performed the following tasks eight times per person, with two types of UAS, with or without M-arm, and with left or right kidney model. Task 1 was to touch the upper, middle and lower renal calyces with the ureteroscope three times each \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB\u003cb\u003e)\u003c/b\u003e, and Task 2 was to extract one stone from each of the upper, middle and lower renal calyces and the renal pelvis with N-circle\u003csup\u003e\u0026reg;\u003c/sup\u003e (Cook Medical) \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC\u003cb\u003e)\u003c/b\u003e. Participants were instructed to remove and reinsert the ureteroscope each time the renal calix was touched or stones were extracted.\u003c/p\u003e \u003cp\u003eThe outcomes of this study were surgical technique performance and surgeon stress. Representing surgical technique performance, we recorded the number of times that the ureteroscope got stuck during insertion (No. stuck), the number of times a stone was dropped during removal (No. drop), the number of times the basket forceps were opened and closed (No. switch), and the time required to accomplish each task (Time task 1 \u0026amp; 2). These outcomes were measured by two observers, and if results differed, they were discussed and finalized. Participants were not informed of the purpose or outcomes of this study. At the end of each task, surgeon stress was assessed using the NASA-Task Load Index (NASA-TLX), a previously validated performance scale. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analyses\u003c/h2\u003e \u003cp\u003eParticipant demographics were compared between the urologists and residents with Chi square tests or Mann-Whitney U tests. The outcomes of this study were compared between Navigator and Flexor, with and without M-arm, ipsilateral and contralateral kidneys to the hand operating the ureteroscope. This was done by Mann-Whitney U tests and overall results were collected, as well as those for urologists, and residents. Statistical analyses were all performed using JMP Pro 13 (SAS Institute, Cary, NC, USA) and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eParticipant demographics\u003c/h2\u003e \u003cp\u003eParticipant demographics was summarized in \u003cb\u003eTable\u0026nbsp;1\u003c/b\u003e. As expected, the urologists were significantly older and had more experience in urology and had thus experienced a higher number of URS procedures than the residents (all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). There was no significant difference between urologists and residents in the basketing technique (one-surgeon or two-surgeon) usually performed (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.61). All participants were right handed, and the percentage of participants who handled the ureteroscope with their left hand was not significantly different between urologists and residents (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.51).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eOutcomes\u003c/h2\u003e \u003cp\u003eOutcomes of this study were compared for each of three surgical factors that may affect the efficiency of stone extraction. The first surgical factor was the difference in ureteral access sheaths. Comparison of outcomes between Navigator and Flexor was shown in \u003cb\u003eTable\u0026nbsp;2\u003c/b\u003e. No. stuck was significantly higher when Navigator was used than when Flexor was used overall, and for urologists, and residents (all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). There were no significant differences between Navigator and Flexor in No. drop, No. switch, or Time task 1 \u0026amp; 2. In the comparison of NASA-TLX, only mental demand was significantly higher when Navigator was used than when Flexor was used for residents (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.04). The second surgical factor was the use or non-use of the M-arm. Outcomes were compared with and without the use of M-arm, but no significant differences were found in any of the outcomes \u003cb\u003e(Table\u0026nbsp;3)\u003c/b\u003e. The third surgical factor was whether the kidney was ipsilateral or contralateral to the hand manipulating the ureteroscope. Comparison of outcomes between the ipsilateral and contralateral sides was shown in \u003cb\u003eTable\u0026nbsp;4\u003c/b\u003e. No. drop was significantly higher in the ipsilateral group than in the contralateral group overall (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.01), and No. switch was significantly higher in the ipsilateral group than in the contralateral group overall and for residents (all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). No significant differences were shown between the ipsilateral and contralateral sides in No. stuck, Time task 1 \u0026amp; 2, or NASA-TLX.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe used f-URSL simulator models to investigate whether three surgical factors (UAS, M-arm and kidney side) could affect the efficiency of stone extraction and surgeon stress in the one-surgeon basketing technique. The differences in UAS and the kidney side were thought to have the potential to influence the efficacy of stone extractions and surgeon stress. To our knowledge, there are few reports on surgical factors affecting the efficiency of stone extraction and surgeon stress, and the present study is the first to focus specifically on differences in UAS and the left or right sides of a kidney.\u003c/p\u003e \u003cp\u003eUAS is commonly used to perform f-URSL for upper urinary tract stones. Advantages include safe and reproducible access to the upper urinary tract, reduction of the intrarenal pressure, and protection of the ureteroscope [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. On the other hand, UAS insertion may increase the risk of acute ureteral injuries and long-term ureteral stricture [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Weighing the advantages and disadvantages, routine use of UAS is not currently recommended, but UAS is a useful instrument when used in select cases. There are many different types of UAS available on the market with different characteristics, lengths, and sizes [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], and one of these characteristics is the introducer-hub structure. The present study revealed that the number of times that the ureteroscope got stuck during insertion was significantly higher when Navigator was used compared with Flexor (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). In consideration of these causes, we evaluated the cross section of each UAS and found that the internal tapering structure was observed more often in Flexor than in Navigator \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA \u003cb\u003eand B)\u003c/b\u003e. In addition, Time task 2 (time required for stone extractions) tended to be shorter for urologists when Flexor was used than when Navigator was used (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.05). Also, mental demand, a sub-score of NASA-TLX, was significantly lower for residents when Flexor was used than when Navigator was used (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.04) \u003cb\u003e(Table\u0026nbsp;2)\u003c/b\u003e. These results suggest that the differences in endoscopic insertability associated with the difference in the introducer-hub structure of UAS may affect the efficiency of stone extractions and surgeon stress. Furthermore, we suggest that this effect may be stronger because the number of times the endoscope is inserted and removed would be greater during actual surgery than during this study.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA single-use basket holder, which connects the basket forceps to the ureteroscope, is useful to maintain stability of the manipulation during f-URSL with the one-surgeon basketing technique [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. M-arm is one of the single-use basket holders available in Japan. The effect of M-arm on the efficiency of stone extraction has not been previously reported. Okada et al. reported that the use of M-arm was beneficial in smoothly facilitating device exchange, and they showed the efficacy of the one-surgeon basketing technique [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Unfortunately, the present study could not demonstrate the effectiveness of M-arm with respect to extraction efficiency or surgeon stress. However, there were several urologist participants in this study who were accustomed to performing f-URSL by the one-surgeon basketing technique and without using the M-arm. We speculated that they had good outcomes without the use of M-arm, which would be a factor in our inability to demonstrate the efficacy of M-arm. Another single-use basket holder is LithoVue Empower\u0026trade; (Boston Scientific), which is available worldwide. Empower is connected to the handle part of the ureteroscope, allowing the surgeon to simultaneously manipulate the ureteroscope and Empower with one hand. This differs from M-arm, in which the surgeon simultaneously manipulates the ureteroscope with one hand and the basket forceps with the other hand [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Coordination of two-handed manipulation is needed, so M-arm-assisted stone extraction is considered to require more proficiency than by Empower. Use of Empower has been reported to significantly reduce the time required for stone extraction and the number of times the basket forceps were opened and closed compared with M-arm [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. This report was a simulator study with participants who were nurses without f-URSL experience, and it showed the usefulness of Empower for beginners. However, there have been no reports on which basket holder (M-arm vs. Empower) is superior when used by skilled surgeons, and we look forward to further validation.\u003c/p\u003e \u003cp\u003eThe ureteroscope moves only vertically (up or down), but by adding rotational manipulation and back and forth movement, the desired movement of the ureteroscope can be achieved. Rotation of ureteroscope is performed by flexion and extension of the wrist. The wrist joint range of motion (ROM) is 68\u0026ndash;83◦ for flexion and 57\u0026ndash;69◦ for extension, with ROM for extension being narrower [\u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Considering the pyelocaliceal anatomy, when approaching the kidney on the ipsilateral side to the hand manipulation of the ureteroscope (e.g., the left kidney when manipulating the ureteroscope with the left hand), the manipulation is primarily an extension of the wrist. For this reason, it was thought that when approaching the ipsilateral kidney, extension movement of the wrist is the main movement, which may make manipulation more difficult due to the ROM of the wrist compared with the approach to the contralateral kidney. In the present study, No. drop and No. switch were significantly higher in the ipsilateral group than in the contralateral group overall (respectively, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.01 and \u0026lt;\u0026thinsp;0.01) \u003cb\u003e(Table\u0026nbsp;4)\u003c/b\u003e. Interestingly, these trends were not observed among urologists who were skilled in ureteroscopic manipulation, but were more pronounced in residents. Recently, an interesting simulator-based study using motion capture showed that ureteroscopic efficiency in f-URS was correlated with head and torso movement [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. If sufficient ureteroscopic manipulation cannot be achieved by wrist rotation alone, elbows, shoulders, and the torso should be moved to represent them. We believe that this report is an important finding related to the results of our study.\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, the simulation models used in this study might differ slightly from actual renal pelvis morphology. Second, our participants varied in the number of cases experienced and in the basketing technique they usually use. Finally, the number of stone extractions was less than actual typical f-URSL. Despite these limitations, this is thought to be the first report to identify the differences in UAS and the renal side as the surgical factors affecting the efficiency of stone extraction during f-URSL with the one-surgeon basketing technique. We hope that these new findings will be used effectively in developing a surgical strategy for f-URSL.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe differences in UAS and the kidney side were surgical factors affecting the efficiency of stone extraction during f-URSL with the one-surgeon basketing technique. Basketing is an indispensable treatment option for achieving stone-free status, and the one-surgeon basketing technique seems to be efficient. We hope that the results of this study will be used effectively in developing treatment strategies for f-URSL.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ef-URSL\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eflexible ureteroscopic lithotripsy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNASA-TLX\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eNASA-Task Load Index\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNo. drop\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ethe number of times the stone was dropped during removal\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNo. stuck\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ethe number of times that the ureteroscope got stuck during insertion\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNo. switch\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ethe number of times the basket forceps were opened and closed\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eROM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003erange of motion\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSWL\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eshock wave lithotripsy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of interests\u003c/h2\u003e \u003cp\u003eThe authors declare that there are no conflicts of interest regarding the publication of this article.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthical approval\u003c/strong\u003e \u003cp\u003eThis was a simulator-based study with no patients, so ethical approval was deemed unnecessary.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eInformed consent\u003c/strong\u003e \u003cp\u003eFor the same reasons as for ethical approval, informed consent for patients was not obtained. Consent for publication of the study was obtained for all participants.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThe authors did not receive support from any organization for the submitted work.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eRD: protocol/project development, data collection and management, data analysis, manuscript writing/editing and illustrations; SH: protocol/project development, data collection, data management and supervision; YI: protocol/project development; HK: protocol/project development; SM: protocol/project development; TW: protocol/project development; YK: protocol/project development and supervision; IH: supervision.All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eThis document was proofread and edited by Benjamin Phillis at the Clinical Study Support Center at Wakayama Medical University.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLv G, Qi W, Gao H et al (2022) Safety and efficacy of extracorporeal shock wave lithotripsy vs. flexible ureteroscopy in the treatment of urinary calculi: A systematic review and meta-analysis. 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PeerJ 8:e9687 \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.7717/peerj.9687\u003c/span\u003e\u003cspan address=\"10.7717/peerj.9687\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 32864213\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValovska MT, Gomez G, Fineman R et al (2022) Analysis of Flexible Ureteroscopic Motion and Kinematic Efficiency: A Simulation-Based Pilot Study. J Endourol 36:855\u0026ndash;861. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1089/end.2021.0726\u003c/span\u003e\u003cspan address=\"10.1089/end.2021.0726\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 4 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Flexible ureteroscopic lithotripsy, Stone extraction, Ureteral access sheath, Simulator-based study","lastPublishedDoi":"10.21203/rs.3.rs-3873413/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3873413/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWhen performing flexible ureteroscopic lithotripsy for upper urinary stones, an important treatment option is stone extraction. In this study, we aim to investigate the surgical factors affecting the efficiency of stone extraction and surgeon stress using a flexible ureteroscopic lithotripsy simulator model. This simulator-based study involved 16 participants: eight urologists and eight residents. Participants each performed two tasks eight times, with two types of ureteral access sheath (Flexor or Navigator), with or without M-arm, and with left or right kidney models. Task1 was to touch each renal calix with the ureteroscope, and Task2 was to extract stones. The recorded outcomes of this study were the number of times that the ureteroscope got stuck during insertion, the number of times a stone was dropped during removal, the number of times the basket forceps were opened and closed, and the time required to accomplish each task. The number of times that the ureteroscope got stuck was significantly higher when Navigator was used compared with Flexor overall, and for urologists and residents (all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). The number of times a stone was dropped was significantly higher in the ipsilateral group than in the contralateral group overall (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.01), and the number of times the basket forceps were opened and closed was significantly higher in the ipsilateral group than in the contralateral group both overall and for residents (all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Differences in ureteral access sheath and the kidney side were surgical factors affecting the efficiency of stone extraction during flexible ureteroscopic lithotripsy with the one-surgeon basketing technique.\u003c/p\u003e","manuscriptTitle":"Verification of surgical factors affecting the efficiency of stone extraction using a f-URSL simulation model","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-19 20:23:51","doi":"10.21203/rs.3.rs-3873413/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3a69c0c5-c40c-4e01-8919-885a114f4abb","owner":[],"postedDate":"January 19th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-02-15T15:50:12+00:00","versionOfRecord":[],"versionCreatedAt":"2024-01-19 20:23:51","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3873413","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3873413","identity":"rs-3873413","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}