Flexible Ureteral Access Sheath with suction -– Does it make a difference in Retrograde intrarenal surgery?

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Chandra Mohan Vaddi, Soundarya Ganesan, Ramakrishna Paidakula, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4496968/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 Aim: The objective is to analyse the safety and efficacy of flexible ureteral access sheath (UAS) during retrograde intrarenal surgery in comparison with conventional ureteral access sheath. Primary aim: To compare the stone free rate (SFR), need for auxiliary procedure, complication rate. Secondary aim: To compare the operative time and intraoperative visibility Materials and Methods: Between April and October 2023, prospectively collected data on RIRS using flexible UAS incorporated with suction (Group A, n=50) was matched with retrospective data on RIRS using conventional UAS (Group B, n=50), done by a single surgeon at a single centre. Demographic data and stone characteristics, intra operative and post operative parameters were collected from hospital database. Propensity matched analysis was done between the two groups after matching for stone size, volume and density. Results: The stone free rate (96% vs 92%, p = 0.678) and overall complication rate (22% vs 26%, p= 0.454) was comparable between the two groups. Group A patients had significantly better intraoperative visibility (100% vs 78% Grade 1 visibility, p<0.001), lesser need for auxiliary procedures (4% vs 16%, p=0.046), lesser incidence of post operative fever (4% vs 14%, p= 0.042) as compared to Group B. One patient in Group B required reintervention for steinstrasse after stent removal, while none in Group A required unplanned reintervention. Conclusion: Flexible UAS with suction during RIRS is advantageous due to better intraoperative visibility, lesser need for auxiliary procedures and lesser infectious complications. Flexible ureteral access sheath Retrograde intrarenal surgery Thulium fibre laser Suction Figures Figure 1 Introduction Retrograde intrarenal surgery (RIRS) is one of the first line treatment of renal stones < 20mm [ 1 ]. Managing intrarenal pressures, control of infectious complications, reduction of auxiliary procedures and achieving a high stone free rate are the important goals of RIRS. It has been proven that usage of ureteral access sheath (UAS) improves intraoperative visibility and reduces the intrarenal pressure, thereby the post operative sepsis rates [ 2 , 3 ]. However, there are certain limitations of UAS usage. Firstly the need for large calibre UAS for effective reduction of intrarenal pressure (IRP) and reduction of sepsis [ 4 ]. Secondly, the UAS is placed most of the times in the proximal ureter, distal to the pelvi-ureteric junction (PUJ) and the physiologic kink in the PUJ can hinder the irrigation fluid outflow [ 5 ]. Thirdly, intraoperative visibility can be hindered by the snow globe effect [ 6 ] during laser lithotripsy or by the presence of fluffy material around the infected stone, which can obscure the residual fragments and compromise the stone free rate, which cannot be dealt with by the conventional UAS. Although RIRS can achieve good stone free rates, the residual fragments (RFs) after RIRS often pose a thorny problem [ 7 ]. The RFs can increase the risk of stone related events and also lead to the recurrence of stone formation [ 8 , 9 ]. Gauhar et al found in his study that residual fragments are found in about 21.7% of patients, out of whom 51.5% required intervention [ 10 ]. All of the above factors make suction incorporated small calibre UAS, the need of the hour. Suction techniques in RIRS can be of 3 types – Irrigation/suctioning system with control of pressure, direct in scope suction (DISS) and suction ureteral access sheath (sUAS) [ 11 ]. It is shown that suction incorporation improves the stone free rates and reduces the complication rates [ 11 ]. On comparing the results of RIRS done using DISS with those of sUAS, Gauhar et al found that, 33.3% of patients in DISS group required a further RIRS whereas only 3.6% of sUAS group required further intervention [ 12 ]. We have evaluated the outcomes of RIRS done with flexible, suctioning UAS and compared the same with RIRS done with conventional UAS. Materials and Methods Between April and October 2023, prospectively collected data on RIRS using flexible suction incorporated ureteral access sheath (Group A, n = 50) was matched with retrospective data on RIRS using conventional UAS (Group B, n = 50), done by a single surgeon at a single centre. Demographic data and stone characteristics, intra operative and post operative parameters were collected from hospital database. Patient with renal and proximal ureteric stones undergoing RIRS were included. Patients with untreated urinary tract infection, diverticular stones, previously operated genitourinary tracts, anomalous anatomy, pregnant and pediatric patients were excluded. Informed consent was taken and ethical committee approval was obtained (ECSTTH/EC Meet 05/2023/04). All patients underwent hemogram, blood biochemistry, urine culture. Non-contrast computed tomogram kidney ureter and bladder (NCCT KUB) was done in all patients for assessment of stone size, volume and density. Patients with active urinary tract infection were treated according to the hospital antibiogram. Prophylactic antibiotic was given to patients with negative urine culture. Surgical technique: All patients underwent initial ureteroscopy using 6/7.5Fr Ureteroscope, after removal of the indwelling DJ stent. Flexible ureteral access sheath with suction, of size 10/12Fr and length 50cm (Aster medispro private limited, Jigani, Bengaluru, Karnataka, India) was used in Group A patients, and conventional ureteral access sheath 9.5/11.5Fr, 28cm (Cook, Flexor) was used in Group B patients. Technique used in Group A: In Group A patients, initial ureteroscopy was done and a terumo guidewire 0.035” was placed in the pelvicalyceal system. Under fluoroscopic guidance the bendable UAS incorporated with suction with obturator was backloaded over the guidewire and placed in the pelvis or proximal ureter, which was confirmed by retrograde pyelogram. The flexible suctioning UAS has a bifurcation at the proximal end, the straight channel has a rubber seal with a central aperture through which the flexible ureteroscope(FURS) is inserted and the oblique channel is connected to the negative pressure aspirator through the suction tube. The oblique channel has a slit on one side which must be occluded by the surgeon while applying suction or for regulation of suction pressure (Fig. 1). The FURS was then inserted through the access sheath into each calyx and the access sheath was navigated into each calyx over the flexible ureteroscope. Lower calyceal stones inaccessible for flexible ureteroscope were relocated using Nitinol basket (N-circle 2.2Fr, Cook Urological or Dakota 1.9Fr, Boston Scientific). Laser lithotripsy was done using Thulium fibre laser (TFL), (Urolase SP+, IPG Photonics, Oxford, Massachusetts, United States). Fragmentation followed by pocorning was done, until fragments, small enough to be sucked out from the UAS, was made. The suction was controlled by the surgeon, by occluding the slit as and when needed. Technique used in Group B: In Group B patients, the conventional UAS was inserted over a 4/6.5Fr semirigid ureteroscope (Richard Wolf, Chicago) using the visual obturator technique. Laser lithotripsy was done using TFL, fragmentation followed by pocorning was done until fine dust, small enough to pass out spontaneously, was formed. Cases in which access sheath insertion failed in either of the two groups, were stented and taken up for the procedure after 2weeks. Flexible ureteroscopy was done using P7 (Olympus, Shinjuku, Tokyo) or IndoscopeTM (Biorad Medisys Pvt. Ltd.) scopes. The settings used for laser lithotripsy were 10-15Hz, 1-1.5J, maximum power 22.5W in fragmentation mode and 100-150Hz, 0.1-0.2J, maximum power 20W popcorn mode, using 200 micron laser fibre. Outcomes measured: The operative time, laser usage time, fluoroscopy time were recorded. Operative time was defined as the time between insertion of ureteral access sheath and its removal. Laser time was recorded from the laser apparatus. Intraoperative visibility was assessed using Likert’s scale (grade 1- excellent, grade 2 – average, grade 3 – poor), recorded by the operating surgeon. Post operative complications were assessed using Clavien-Dindo grading. Stone free rate was calculated using NCCT KUB at the end of 2months and stone size > 2mm was considered significant. Statistical Analysis: Data were coded and recorded in MS Excel spreadsheet program. SPSS v23 (IBM Corp.) was used for data analysis. Descriptive statistics were elaborated in the form of means/standard deviations and medians/IQRs for continuous variables, and frequencies and percentages for categorical variables. Group comparisons for continuously distributed data were made using independent sample ‘t’ test when comparing two groups. If data were found to be non-normally distributed, appropriate non-parametric tests in the form of Wilcoxon Test were used. Chi- squared test was used for group comparisons for categorical data. In case the expected frequency in the contingency tables was found to be 25% of the cells, Fisher’s Exact test was used instead. Linear correlation between two continuous variables was explored using Pearson’s correlation (if the data were normally distributed) and Spearman’s correlation (for non-normally distributed data). Statistical significance was kept at p < 0.05. Results The demographic details of patients and stone characteristics are depicted in table 1. The operative time was higher in Group A (50.24 ± 13.00 vs 44.36 ± 14.33, p= 0.011). The intraoperative visibility was significantly better in Group A (100% vs 78% grade 1 visibility, p <0.001) and the requirement for auxiliary procedure was significantly lower in group A [2 /50 (4.0%) vs 8/50 (16.0%), p = 0.046]. The incidence of post operative fever was significantly lower in group A (4% vs 14%, p= 0.042). There was no significant difference in the stone free rate at 2months (96% vs 92%, p = 0.678) and overall complication rate (22% vs 26%, p= 0.454) between the two groups. One patient in Group B required reintervention for steinstrasse after stent removal, while none in Group A required unplanned reintervention. The mean follow up period is 3.9 (0.52) and 5.4 (0.38) months, in groups A and B respectively, p = 0.452. Table 1. Demographic data and stone parameters Parameter Group A (n=50) Group B (n=50) P value Age (years) 42.26 ± 14.64 45.46 ± 11.80 0.232 1 Gender Male Female 33 (66.0%) 17 (34.0%) 38 (76.0%) 12 (24.0%) 0.271 2 Laterality Right Left 26 (52.0%) 24 (48.0%) 20 (40.0%) 30 (60.0%) 0.229 2 Number of Stones 0.483 3 Single 37(74.0%) 40 (80.0%) Multiple 13 (26.0%) 10 (20.0%) Location: Upper Calyx (Yes) 12 (24.0%) 8 (16.0%) 0.317 2 Location: Middle Calyx (Yes) 15 (30.0%) 17 (34.0%) 0.668 2 Location: Lower Calyx (Yes) 14 (28.0%) 10 (20.0%) 0.349 2 Location: Pelvis (Yes) 9 (18.0%) 7 (14.0%) 0.585 2 Location: Proximal Ureter (Yes) 15 (30.0%) 10 (20.0%) 0.248 2 Mean Stone Size (mm) 14.23 ± 5.34 14.85 ± 3.56 0.138 4 Volume (mm³) 1295.06 ± 679.56 1273.35 ± 579.37 0.882 4 Density (HU) 979.78 ± 221.37 963.32 ± 382.96 0.793 1 Pre-Stented (Yes)*** 38 (76.0%) 18 (36.0%) <0.001 2 Table 2. Comparison of Intraoperative and Post operative parameters between Groups A and B Parameter Group A (n=50) Group B (n=50) P value Total Operative Time (min)*** 50.24 ± 13.00 44.36 ± 14.33 0.011 4 Laser Time (sec) 1078.64 ± 459.41 1164.98 ± 474.83 0.593 4 Fluoroscopy Time (sec)*** 68.20 ± 25.67 26.04 ± 26.90 <0.001 4 Visibility*** Score 1 - Excellent Score 2 - Average Score 3 - Poor 50 (100.0%) 0 (0.0%) 0 (0.0%) 39 (78.0%) 5 (10.0%) 6 (12.0%) <0.001 3 Relook (Required)*** 2 (4.0%) 8 (16.0%) 0.046 2 Fever - CD Grade*** Absent 1 2 48 (96.0%) 1 (2.0%) 1 (2.0%) 43 (86.0%) 0 (0.0%) 7 (14.0%) 0.042 3 Hematuria - CD Grade Absent 1 45 (90.0%) 5 (10.0%) 47 (94.0%) 3 (6.0%) 0.715 3 Pain - CD Grade Absent 2 46 (92.0%) 4 (8.0%) 47 (94.0%) 3 (6.0%) 1.000 3 Complication Rate, n (%) 11/50 (22%) 13/50 (26%) 0.454 3 Stone Free At 2 Months (Yes) 48 (96.0%) 46 (92.0%) 0.678 3 Complications Requiring Reintervention >4 Weeks (Steinstrasse/Renal Colic) Yes None 0 (0.0%) 50 (100.0%) 1 (2.0%) 49 (98.0%) 1.000 3 Reintervention Required Yes None 0 (0.0%) 50 (100.0%) 1 (2.0%) 49 (98.0%) 1.000 3 Intra-Operative Ureteric Injury None Grade 1 49 (98.0%) 1 (2.0%) 48 (96.0%) 2 (4.0%) 1.000 3 Intra-Operative PCS Injury None Grade 1 49 (98.0%) 1 (2.0%) 50 (100.0%) 0 (0.0%) 1.000 3 Discussion RIRS is considered as a first line treatment for stones 10-20mm in size, with lesser complications and comparable success rates as PCNL [ 13 ]. The overall stone free rate is appproximately 90% after RIRS in less than 20mm stones [ 14 ]. Zhu et al. compared the efficacy between a suctioning UAS and traditional UAS [ 15 ]. The suctioning UAS group had a significantly higher SFR on postoperative day one (82.4% vs. 71.5%; P = 0.02), but the SFR at 1 month postoperatively was comparable in the two groups (88.8% vs 82.9%, P = 0.13). Yu et al in a similar study [ 16 ], showed that there was no significant difference in SFR at 1 month postoperatively ( P = 0.627). In our study, there was no significant difference in the SFR between the two groups at the end of 2months (96% vs 92%, p = 0.678). The natural history of residual fragments after RIRS was studied by Atis et al [ 17 ], and he observed that spontaneous passage of less than 4mm residual fragments occurred in only 30.23% of patients. Hein et al [ 8 ] found that stone related events occurred in 30.1% (26 out of 85 patients) after RIRS. Kang et al (9) concluded from his study on 126 patients that the microparticles that could not be removed after RIRS could increase the risk of recurrence and stone related events. As the stone size and volume increases, the need for auxiliary procedures also increases to achieve high SFR. For every 1000mm 3 increase in stone volume, requirement of auxiliary procedure increases by 2.8 times [ 18 ]. Therefore it is important to achieve reasonably high SFR while minimising the auxiliary procedure rate. The need for auxiliary procedures was found to be 8.7% after RIRS for 10-20mm renal stones by Resorlu et al [ 19 ]. The use of suction incorporated access sheath in our study, allowed for a significant reduction in the need for auxiliary procedure from 16–4%. Steinstrasse was found in 2 out of 151 patients (1.3%) by Mahmood et al [ 20 ] in his study comparing RIRS and PCNL for 1-2cm stones. In our study steinstrasse was found in 1 out of 50 patients in group B who underwent RIRS using conventional UAS, while none in group A had developed this complication. The studies done by Zhu et al and Yu et al [ 15 , 16 ], comparing the suctioning UAS with the traditional UAS, were done using 12/14Fr suctioning UAS, however they found no significant difference in the incidence of ureteral perforation or ureteral stricture. We have used 10/12Fr suctioning UAS. There was no significant difference in the incidence of ureteral injury or stricture, between the two groups in the given follow up period. The incidence of infectious complications after RIRS has been reported to range from 0.5% − 11.1% [ 21 ] and the risk factors were found to be stone size, high irrigation pressure, prolonged stent dwelling time, sepsis as an indication for stent insertion, female gender, positive intraoperative bladder urine culture, longer surgical time, and diabetes mellitus. The suctioning UAS enables reduction of the intrarenal pressure and thereby the sepsis rates [ 22 , 23 , 15 , 16 ]. Zhu et al [ 15 ] showed a significant reduction of post operative fever in the suctioning UAS group (5.5% vs 13.9%; P = 0.009). Similarly, we found significantly lower rates of post operative fever in the suctioning UAS group (4% vs 14%, p = 0.042). There was no significant association found between the post operative fever and the rate of preoperative stenting in both the groups (χ2 = 0.183, p = 0.738). There was no significant difference in the overall complication rate between the two groups (22% vs 26%, p = 0.454). As regards to the endoscopic visibility, group A patients had better visibility compared to group B (p < 0.001), (Table 2 ). Similar findings were observed by Zeng et al, who reported that the use of modified UAS optimized the intraoperative visibility throughout the procedure [ 22 ]. The operative time was found to be shorter in the suctioning UAS group by Zhu et al and Yu et al (15,16). On the contrary, we found longer operating time in the suctioning UAS group (50.24 ± 13.00 min vs 44.36 ± 14.33 min, p = 0.011). This could be explained by the differences in the surgical technique, because, at the end of laser lithotripsy, extra time was taken for suctioning the stone fragments a little by little into the suctioning UAS, by withdrawing the scope until the bifurcation. This had to be done until all the visible fragments were cleared in order to achieve spot intraoperative stone clearance. This had to be patiently and was therefore time consuming. In addition, we found the fluoroscopy time to be longer in group A, as the insertion of suctioning UAS was done under fluoroscopic guidance, whilst the traditional UAS was inserted using visual obturator technique, minimising the need for fluoroscopy (Table 2 ). Prevention of sepsis, controlling the intrarenal pressure, minimising the residual fragments and reintervention are important targets in RIRS. By incorporating suction in UAS, these goals of RIRS are achieved. The suction incorporated UAS is a landmark innovation as it joins the list of game changers in RIRS, namely the thulium fiber laser and the digital disposable flexible ureteroscopes [ 24 ]. It is also proposed that there is a reduced need for basket usage, which can cut down the surgical costs [ 16 ]. The other advantages are, the learning curve is short, suction is controlled by the surgeon himself, which can be continuous or on demand, without affecting the irrigation fluid inflow, intraoperative suction allows to reduce the “snow globe effect” which allows for uninterrupted lithotripsy, ability to suck the blood clots which can hamper the visibility, ability to suck the matrix around the stone, which is not amenable for laser lithotripsy, and navigability to almost all calyces with ease. Strengths and Limitations: Strengths: The study is the first of its kind using a small calibre suction incorporated UAS (10/12Fr), comparing the clinical outcomes with the conventional UAS. Propensity matching was done for the data to be comparable, in order to eliminate the confounding factors. The procedures were done by a single surgeon at a single centre. Limitations: It is not a randomised controlled study. The follow up period is short and therefore there is limited information on the long term outcomes. The stent dwell time was not analysed, and the rate of preoperative stenting was different between the two groups as 76% were pre-stented in group A, while only 36% were pre-stented in group B (p < 0.001). This is a limitation because the stent dwell time also is a risk factor for post operative fevers. The lithotripsy technique is not uniform between the two groups, as the end point was dust in group B, but fragments in group A, which could have had an impact on the operating time. Conclusion The suction incorporated ureteral access sheath is a revolutionary innovation which can optimise the outcomes of RIRS. Our results show a reduction in the need for auxiliary procedures and the incidence of post operative fever rates, with comparable overall complication rate and stone free rate. The improved endoscopic visibility is an added advantage. Thus suction incorporated flexible UAS seems to make a difference in RIRS. Declarations Funding: No funds, grants, or other support was received The authors have no relevant financial or non-financial interests to disclose The authors have no competing interests to declare that are relevant to the content of this article Ethics Approval: Obtained from our institutional ethics committee. Approval number : ECSTTH/EC Meet 05/2023/04 Informed consent was obtained from all individual participants included in the study. Author Contribution Statement: CHANDRAMOHAN VADDI: Project development, Data collection, Manuscript editing SOUNDARYA GANESAN: Data collection, Data analysis, Manuscript writing RAMAKRISHNA PAIDAKULA: Data collection, Manuscript editing SIDDALINGA SWAMY P M: Manuscript editing HEMNATH ANANDAN: Manuscript editing RAKESH PANDA: Manuscript editing Acknowledgement None Data Availability Data cannot be shared openly but are available on request from authors References Skolarikos A, Neisius A, Petřík A, Somani B, Thomas K, Gambaro G, Tzelves L (2022) Urolithiasis. EAU Guidelines. Edn. presented at the EAU Annual Congress Amsterdam Tonyali S (2019) Suctioning ureteral access sheath use in flexible ureteroscopy might decrease operation time and prevent infectious complications. 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J Endourol 30(9):992–996. https://doi.org/10.1089/end.2016.0411 Pauchard F, Ventimiglia E, Corrales M, Traxer O (2022) A practical guide for intra-renal temperature and pressure management during RIRS: what is the evidence telling us. J Clin Med 11(12):3429. https://doi.org/10.3390/jcm11123429 De Coninck, V., Somani, B., Sener, E. T., Emiliani, E., Corrales, M., Juliebø-Jones,P., … Keller, E. X. (2022). Ureteral access sheaths and its use in the future: a comprehensive update based on a literature review. Journal of Clinical Medicine, 11(17), 5128. https://doi.org/10.3390/jcm11175128 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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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-4496968","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":313976576,"identity":"34dc2d1a-bdd7-43d8-b3de-c32aceaf648e","order_by":0,"name":"Chandra Mohan Vaddi","email":"","orcid":"","institution":"Preeti Urology and Kidney hospital","correspondingAuthor":false,"prefix":"","firstName":"Chandra","middleName":"Mohan","lastName":"Vaddi","suffix":""},{"id":313976577,"identity":"0d63685e-25da-48b7-927b-7541d9485feb","order_by":1,"name":"Soundarya Ganesan","email":"data:image/png;base64,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","orcid":"","institution":"Preeti Urology and Kidney hospital","correspondingAuthor":true,"prefix":"","firstName":"Soundarya","middleName":"","lastName":"Ganesan","suffix":""},{"id":313976578,"identity":"75f666d8-3383-4489-8b86-cc26443c9e03","order_by":2,"name":"Ramakrishna Paidakula","email":"","orcid":"","institution":"Preeti Urology and Kidney hospital","correspondingAuthor":false,"prefix":"","firstName":"Ramakrishna","middleName":"","lastName":"Paidakula","suffix":""},{"id":313976579,"identity":"d041e5bf-d9c4-4d44-91c3-288ccfb8ca98","order_by":3,"name":"Siddalinga Swamy","email":"","orcid":"","institution":"Preeti Urology and Kidney hospital","correspondingAuthor":false,"prefix":"","firstName":"Siddalinga","middleName":"","lastName":"Swamy","suffix":""},{"id":313976580,"identity":"8711545e-3d9d-4fcc-b7bf-093f78ecfc7a","order_by":4,"name":"Hemnath Anandan","email":"","orcid":"","institution":"Preeti Urology and Kidney hospital","correspondingAuthor":false,"prefix":"","firstName":"Hemnath","middleName":"","lastName":"Anandan","suffix":""},{"id":313976581,"identity":"1c2f86ac-f7a7-461f-bae9-2c30b7a5666e","order_by":5,"name":"Rakesh Panda","email":"","orcid":"","institution":"Preeti Urology and Kidney hospital","correspondingAuthor":false,"prefix":"","firstName":"Rakesh","middleName":"","lastName":"Panda","suffix":""}],"badges":[],"createdAt":"2024-05-29 12:11:44","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4496968/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4496968/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":58386425,"identity":"29941f8e-d532-4742-b0a7-4659a748754f","added_by":"auto","created_at":"2024-06-14 18:44:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2409439,"visible":true,"origin":"","legend":"\u003cp\u003ea. Flexible suctioning UAS with obturator and negative pressure aspirator\u003c/p\u003e\n\u003cp\u003e1b. Parts of the negative pressure aspirator – suction container, sieve and valve for control of suction\u003c/p\u003e\n\u003cp\u003e1c. Assembled negative pressure aspirator\u003c/p\u003e\n\u003cp\u003e1d. Efflux from UAS connected to aspirator and efflux from aspirator connected to suction container\u003c/p\u003e\n\u003cp\u003e1e. Red arrow shows the slit in the oblique channel\u003c/p\u003e","description":"","filename":"FANSpic3001.png","url":"https://assets-eu.researchsquare.com/files/rs-4496968/v1/5beb3c9947e40dd42eb37d5a.png"},{"id":58887228,"identity":"7a789ddf-83d7-4395-b26b-18c25bf00486","added_by":"auto","created_at":"2024-06-23 11:10:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2927165,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4496968/v1/8cf56124-fdc8-4e23-a103-18c30b536345.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Flexible Ureteral Access Sheath with suction -– Does it make a difference in Retrograde intrarenal surgery?","fulltext":[{"header":"Introduction","content":"\u003cp\u003eRetrograde intrarenal surgery (RIRS) is one of the first line treatment of renal stones\u0026thinsp;\u0026lt;\u0026thinsp;20mm [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Managing intrarenal pressures, control of infectious complications, reduction of auxiliary procedures and achieving a high stone free rate are the important goals of RIRS. It has been proven that usage of ureteral access sheath (UAS) improves intraoperative visibility and reduces the intrarenal pressure, thereby the post operative sepsis rates [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, there are certain limitations of UAS usage. Firstly the need for large calibre UAS for effective reduction of intrarenal pressure (IRP) and reduction of sepsis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Secondly, the UAS is placed most of the times in the proximal ureter, distal to the pelvi-ureteric junction (PUJ) and the physiologic kink in the PUJ can hinder the irrigation fluid outflow [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Thirdly, intraoperative visibility can be hindered by the snow globe effect [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] during laser lithotripsy or by the presence of fluffy material around the infected stone, which can obscure the residual fragments and compromise the stone free rate, which cannot be dealt with by the conventional UAS.\u003c/p\u003e \u003cp\u003eAlthough RIRS can achieve good stone free rates, the residual fragments (RFs) after RIRS often pose a thorny problem [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The RFs can increase the risk of stone related events and also lead to the recurrence of stone formation [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Gauhar et al found in his study that residual fragments are found in about 21.7% of patients, out of whom 51.5% required intervention [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAll of the above factors make suction incorporated small calibre UAS, the need of the hour. Suction techniques in RIRS can be of 3 types \u0026ndash; Irrigation/suctioning system with control of pressure, direct in scope suction (DISS) and suction ureteral access sheath (sUAS) [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. It is shown that suction incorporation improves the stone free rates and reduces the complication rates [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. On comparing the results of RIRS done using DISS with those of sUAS, Gauhar et al found that, 33.3% of patients in DISS group required a further RIRS whereas only 3.6% of sUAS group required further intervention [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. We have evaluated the outcomes of RIRS done with flexible, suctioning UAS and compared the same with RIRS done with conventional UAS.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eBetween April and October 2023, prospectively collected data on RIRS using flexible suction incorporated ureteral access sheath (Group A, n\u0026thinsp;=\u0026thinsp;50) was matched with retrospective data on RIRS using conventional UAS (Group B, n\u0026thinsp;=\u0026thinsp;50), done by a single surgeon at a single centre. Demographic data and stone characteristics, intra operative and post operative parameters were collected from hospital database. Patient with renal and proximal ureteric stones undergoing RIRS were included. Patients with untreated urinary tract infection, diverticular stones, previously operated genitourinary tracts, anomalous anatomy, pregnant and pediatric patients were excluded. Informed consent was taken and ethical committee approval was obtained (ECSTTH/EC Meet 05/2023/04).\u003c/p\u003e\n\u003cp\u003eAll patients underwent hemogram, blood biochemistry, urine culture. Non-contrast computed tomogram kidney ureter and bladder (NCCT KUB) was done in all patients for assessment of stone size, volume and density. Patients with active urinary tract infection were treated according to the hospital antibiogram. Prophylactic antibiotic was given to patients with negative urine culture.\u003c/p\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eSurgical technique:\u003c/h2\u003e\n \u003cp\u003eAll patients underwent initial ureteroscopy using 6/7.5Fr Ureteroscope, after removal of the indwelling DJ stent. Flexible ureteral access sheath with suction, of size 10/12Fr and length 50cm (Aster medispro private limited, Jigani, Bengaluru, Karnataka, India) was used in Group A patients, and conventional ureteral access sheath 9.5/11.5Fr, 28cm (Cook, Flexor) was used in Group B patients.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003eTechnique used in Group A:\u003c/h2\u003e\n \u003cp\u003eIn Group A patients, initial ureteroscopy was done and a terumo guidewire 0.035\u0026rdquo; was placed in the pelvicalyceal system. Under fluoroscopic guidance the bendable UAS incorporated with suction with obturator was backloaded over the guidewire and placed in the pelvis or proximal ureter, which was confirmed by retrograde pyelogram. The flexible suctioning UAS has a bifurcation at the proximal end, the straight channel has a rubber seal with a central aperture through which the flexible ureteroscope(FURS) is inserted and the oblique channel is connected to the negative pressure aspirator through the suction tube. The oblique channel has a slit on one side which must be occluded by the surgeon while applying suction or for regulation of suction pressure (Fig.\u0026nbsp;1).\u003c/p\u003e\n \u003cp\u003eThe FURS was then inserted through the access sheath into each calyx and the access sheath was navigated into each calyx over the flexible ureteroscope. Lower calyceal stones inaccessible for flexible ureteroscope were relocated using Nitinol basket (N-circle 2.2Fr, Cook Urological or Dakota 1.9Fr, Boston Scientific). Laser lithotripsy was done using Thulium fibre laser (TFL), (Urolase SP+, IPG Photonics, Oxford, Massachusetts, United States). Fragmentation followed by pocorning was done, until fragments, small enough to be sucked out from the UAS, was made. The suction was controlled by the surgeon, by occluding the slit as and when needed.\u003c/p\u003e\n \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e\n \u003ch2\u003eTechnique used in Group B:\u003c/h2\u003e\n \u003cp\u003eIn Group B patients, the conventional UAS was inserted over a 4/6.5Fr semirigid ureteroscope (Richard Wolf, Chicago) using the visual obturator technique. Laser lithotripsy was done using TFL, fragmentation followed by pocorning was done until fine dust, small enough to pass out spontaneously, was formed.\u003c/p\u003e\n \u003cp\u003eCases in which access sheath insertion failed in either of the two groups, were stented and taken up for the procedure after 2weeks. Flexible ureteroscopy was done using P7 (Olympus, Shinjuku, Tokyo) or IndoscopeTM (Biorad Medisys Pvt. Ltd.) scopes. The settings used for laser lithotripsy were 10-15Hz, 1-1.5J, maximum power 22.5W in fragmentation mode and 100-150Hz, 0.1-0.2J, maximum power 20W popcorn mode, using 200 micron laser fibre.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e\n \u003ch2\u003eOutcomes measured:\u003c/h2\u003e\n \u003cp\u003eThe operative time, laser usage time, fluoroscopy time were recorded. Operative time was defined as the time between insertion of ureteral access sheath and its removal. Laser time was recorded from the laser apparatus. Intraoperative visibility was assessed using Likert\u0026rsquo;s scale (grade 1- excellent, grade 2 \u0026ndash; average, grade 3 \u0026ndash; poor), recorded by the operating surgeon. Post operative complications were assessed using Clavien-Dindo grading. Stone free rate was calculated using NCCT KUB at the end of 2months and stone size\u0026thinsp;\u0026gt;\u0026thinsp;2mm was considered significant.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eStatistical Analysis:\u003c/h2\u003e\n \u003cp\u003eData were coded and recorded in MS Excel spreadsheet program. SPSS v23 (IBM Corp.) was used for data analysis. Descriptive statistics were elaborated in the form of means/standard deviations and medians/IQRs for continuous variables, and frequencies and percentages for categorical variables. Group comparisons for continuously distributed data were made using independent sample \u0026lsquo;t\u0026rsquo; test when comparing two groups. If data were found to be non-normally distributed, appropriate non-parametric tests in the form of Wilcoxon Test were used. Chi- squared test was used for group comparisons for categorical data. In case the expected frequency in the contingency tables was found to be \u0026lt;\u0026thinsp;5 for \u0026gt;\u0026thinsp;25% of the cells, Fisher\u0026rsquo;s Exact test was used instead. Linear correlation between two continuous variables was explored using Pearson\u0026rsquo;s correlation (if the data were normally distributed) and Spearman\u0026rsquo;s correlation (for non-normally distributed data). Statistical significance was kept at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThe demographic details of patients and stone characteristics are depicted in table 1. The operative time was higher in Group A (50.24 \u0026plusmn; 13.00 vs 44.36 \u0026plusmn; 14.33, p= 0.011). The intraoperative visibility was significantly better in Group A (100% vs 78% grade 1 visibility, p \u0026lt;0.001) and the requirement for auxiliary procedure was significantly lower in group A [2 /50 (4.0%) vs 8/50 (16.0%), p = 0.046]. The incidence of post operative fever was significantly lower in group A (4% vs 14%, p= 0.042). There was no significant difference in the stone free rate at 2months (96% vs 92%, p = 0.678) and overall complication rate (22% vs 26%, p= 0.454) between the two groups. One patient in Group B required reintervention for steinstrasse after stent removal, while none in Group A required unplanned reintervention. The mean follow up period is 3.9 (0.52) and 5.4 (0.38) months, in groups A and B respectively, p = 0.452.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1. Demographic data and stone parameters\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eParameter\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup A (n=50)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup B (n=50)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge (years)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e42.26 \u0026plusmn; 14.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e45.46 \u0026plusmn; 11.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.232\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGender\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e33 (66.0%)\u003c/p\u003e\n \u003cp\u003e17 (34.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e38 (76.0%)\u003c/p\u003e\n \u003cp\u003e12 (24.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.271\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLaterality\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eRight\u003c/p\u003e\n \u003cp\u003eLeft\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e26 (52.0%)\u003c/p\u003e\n \u003cp\u003e24 (48.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e20 (40.0%)\u003c/p\u003e\n \u003cp\u003e30 (60.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.229\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eNumber of Stones\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.483\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Single\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e37(74.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e40 (80.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Multiple\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e13 (26.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e10 (20.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocation: Upper Calyx (Yes)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e12 (24.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e8 (16.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.317\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocation: Middle Calyx (Yes)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e15 (30.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e17 (34.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.668\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocation: Lower Calyx (Yes)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e14 (28.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e10 (20.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.349\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocation: Pelvis (Yes)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e9 (18.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e7 (14.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.585\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocation: Proximal Ureter (Yes)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e15 (30.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e10 (20.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.248\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean Stone Size (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e14.23 \u0026plusmn; 5.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e14.85 \u0026plusmn; 3.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.138\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eVolume (mm\u0026sup3;)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e1295.06 \u0026plusmn; 679.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e1273.35 \u0026plusmn; 579.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.882\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003eDensity (HU)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e979.78 \u0026plusmn; 221.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e963.32 \u0026plusmn; 382.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e0.793\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.357142857142858%\"\u003e\n \u003cp\u003e\u003cstrong\u003ePre-Stented (Yes)***\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.642857142857142%\"\u003e\n \u003cp\u003e38 (76.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e18 (36.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2. Comparison of Intraoperative and Post operative parameters between Groups A and B\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eParameter\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup A (n=50)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup B (n=50)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal Operative Time (min)***\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e50.24 \u0026plusmn; 13.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e44.36 \u0026plusmn; 14.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e0.011\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLaser Time (sec)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1078.64 \u0026plusmn; 459.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e1164.98 \u0026plusmn; 474.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e0.593\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFluoroscopy Time (sec)***\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e68.20 \u0026plusmn; 25.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e26.04 \u0026plusmn; 26.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVisibility***\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eScore 1 - Excellent\u003c/p\u003e\n \u003cp\u003eScore 2 - Average\u003c/p\u003e\n \u003cp\u003eScore 3 - Poor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e50 (100.0%)\u003c/p\u003e\n \u003cp\u003e0 (0.0%)\u003c/p\u003e\n \u003cp\u003e0 (0.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e39 (78.0%)\u003c/p\u003e\n \u003cp\u003e5 (10.0%)\u003c/p\u003e\n \u003cp\u003e6 (12.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eRelook (Required)***\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e2 (4.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e8 (16.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e0.046\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFever - CD Grade***\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eAbsent\u003c/p\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e48 (96.0%)\u003c/p\u003e\n \u003cp\u003e1 (2.0%)\u003c/p\u003e\n \u003cp\u003e1 (2.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e43 (86.0%)\u003c/p\u003e\n \u003cp\u003e0 (0.0%)\u003c/p\u003e\n \u003cp\u003e7 (14.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e0.042\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eHematuria - CD Grade\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAbsent\u003c/p\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e45 (90.0%)\u003c/p\u003e\n \u003cp\u003e5 (10.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e47 (94.0%)\u003c/p\u003e\n \u003cp\u003e3 (6.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e0.715\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePain - CD Grade\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eAbsent\u003c/p\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e46 (92.0%)\u003c/p\u003e\n \u003cp\u003e4 (8.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e47 (94.0%)\u003c/p\u003e\n \u003cp\u003e3 (6.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e1.000\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eComplication Rate, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e11/50 (22%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e13/50 (26%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e0.454\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eStone Free At 2 Months (Yes)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e48 (96.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e46 (92.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e0.678\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eComplications Requiring Reintervention \u0026gt;4 Weeks (Steinstrasse/Renal Colic)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eYes\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eNone\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0 (0.0%)\u003c/p\u003e\n \u003cp\u003e50 (100.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e1 (2.0%)\u003c/p\u003e\n \u003cp\u003e49 (98.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e1.000\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eReintervention Required\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eYes\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eNone\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0 (0.0%)\u003c/p\u003e\n \u003cp\u003e50 (100.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e1 (2.0%)\u003c/p\u003e\n \u003cp\u003e49 (98.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\" valign=\"top\"\u003e\n \u003cp\u003e1.000\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e\u003cstrong\u003eIntra-Operative Ureteric Injury\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eNone\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e49 (98.0%)\u003c/p\u003e\n \u003cp\u003e1 (2.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\"\u003e\n \u003cp\u003e\u003cbr\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e48 (96.0%)\u003c/p\u003e\n \u003cp\u003e2 (4.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\"\u003e\n \u003cp\u003e1.000\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eIntra-Operative PCS Injury\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eNone\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eGrade 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e49 (98.0%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e1 (2.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.383116883116884%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e50 (100.0%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0 (0.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.616883116883116%\"\u003e\n \u003cp\u003e1.000\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003eRIRS is considered as a first line treatment for stones 10-20mm in size, with lesser complications and comparable success rates as PCNL [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The overall stone free rate is appproximately 90% after RIRS in less than 20mm stones [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Zhu et al. compared the efficacy between a suctioning UAS and traditional UAS [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The suctioning UAS group had a significantly higher SFR on postoperative day one (82.4% vs. 71.5%; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.02), but the SFR at 1 month postoperatively was comparable in the two groups (88.8% vs 82.9%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.13). Yu et al in a similar study [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], showed that there was no significant difference in SFR at 1 month postoperatively (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.627). In our study, there was no significant difference in the SFR between the two groups at the end of 2months (96% vs 92%, p\u0026thinsp;=\u0026thinsp;0.678).\u003c/p\u003e \u003cp\u003eThe natural history of residual fragments after RIRS was studied by Atis et al [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], and he observed that spontaneous passage of less than 4mm residual fragments occurred in only 30.23% of patients. Hein et al [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] found that stone related events occurred in 30.1% (26 out of 85 patients) after RIRS. Kang et al (9) concluded from his study on 126 patients that the microparticles that could not be removed after RIRS could increase the risk of recurrence and stone related events. As the stone size and volume increases, the need for auxiliary procedures also increases to achieve high SFR. For every 1000mm\u003csup\u003e3\u003c/sup\u003e increase in stone volume, requirement of auxiliary procedure increases by 2.8 times [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Therefore it is important to achieve reasonably high SFR while minimising the auxiliary procedure rate.\u003c/p\u003e \u003cp\u003eThe need for auxiliary procedures was found to be 8.7% after RIRS for 10-20mm renal stones by Resorlu et al [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The use of suction incorporated access sheath in our study, allowed for a significant reduction in the need for auxiliary procedure from 16\u0026ndash;4%.\u003c/p\u003e \u003cp\u003eSteinstrasse was found in 2 out of 151 patients (1.3%) by Mahmood et al [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] in his study comparing RIRS and PCNL for 1-2cm stones. In our study steinstrasse was found in 1 out of 50 patients in group B who underwent RIRS using conventional UAS, while none in group A had developed this complication.\u003c/p\u003e \u003cp\u003eThe studies done by Zhu et al and Yu et al [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], comparing the suctioning UAS with the traditional UAS, were done using 12/14Fr suctioning UAS, however they found no significant difference in the incidence of ureteral perforation or ureteral stricture. We have used 10/12Fr suctioning UAS. There was no significant difference in the incidence of ureteral injury or stricture, between the two groups in the given follow up period.\u003c/p\u003e \u003cp\u003eThe incidence of infectious complications after RIRS has been reported to range from 0.5% \u0026minus;\u0026thinsp;11.1% [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] and the risk factors were found to be stone size, high irrigation pressure, prolonged stent dwelling time, sepsis as an indication for stent insertion, female gender, positive intraoperative bladder urine culture, longer surgical time, and diabetes mellitus. The suctioning UAS enables reduction of the intrarenal pressure and thereby the sepsis rates [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Zhu et al [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] showed a significant reduction of post operative fever in the suctioning UAS group (5.5% vs 13.9%; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.009). Similarly, we found significantly lower rates of post operative fever in the suctioning UAS group (4% vs 14%, p\u0026thinsp;=\u0026thinsp;0.042). There was no significant association found between the post operative fever and the rate of preoperative stenting in both the groups (χ2\u0026thinsp;=\u0026thinsp;0.183, p\u0026thinsp;=\u0026thinsp;0.738). There was no significant difference in the overall complication rate between the two groups (22% vs 26%, p\u0026thinsp;=\u0026thinsp;0.454).\u003c/p\u003e \u003cp\u003eAs regards to the endoscopic visibility, group A patients had better visibility compared to group B (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Similar findings were observed by Zeng et al, who reported that the use of modified UAS optimized the intraoperative visibility throughout the procedure [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe operative time was found to be shorter in the suctioning UAS group by Zhu et al and Yu et al (15,16). On the contrary, we found longer operating time in the suctioning UAS group (50.24\u0026thinsp;\u0026plusmn;\u0026thinsp;13.00 min vs 44.36\u0026thinsp;\u0026plusmn;\u0026thinsp;14.33 min, p\u0026thinsp;=\u0026thinsp;0.011). This could be explained by the differences in the surgical technique, because, at the end of laser lithotripsy, extra time was taken for suctioning the stone fragments a little by little into the suctioning UAS, by withdrawing the scope until the bifurcation. This had to be done until all the visible fragments were cleared in order to achieve spot intraoperative stone clearance. This had to be patiently and was therefore time consuming. In addition, we found the fluoroscopy time to be longer in group A, as the insertion of suctioning UAS was done under fluoroscopic guidance, whilst the traditional UAS was inserted using visual obturator technique, minimising the need for fluoroscopy (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePrevention of sepsis, controlling the intrarenal pressure, minimising the residual fragments and reintervention are important targets in RIRS. By incorporating suction in UAS, these goals of RIRS are achieved. The suction incorporated UAS is a landmark innovation as it joins the list of game changers in RIRS, namely the thulium fiber laser and the digital disposable flexible ureteroscopes [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. It is also proposed that there is a reduced need for basket usage, which can cut down the surgical costs [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The other advantages are, the learning curve is short, suction is controlled by the surgeon himself, which can be continuous or on demand, without affecting the irrigation fluid inflow, intraoperative suction allows to reduce the \u0026ldquo;snow globe effect\u0026rdquo; which allows for uninterrupted lithotripsy, ability to suck the blood clots which can hamper the visibility, ability to suck the matrix around the stone, which is not amenable for laser lithotripsy, and navigability to almost all calyces with ease.\u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eStrengths and Limitations:\u003c/h2\u003e \u003cp\u003eStrengths: The study is the first of its kind using a small calibre suction incorporated UAS (10/12Fr), comparing the clinical outcomes with the conventional UAS. Propensity matching was done for the data to be comparable, in order to eliminate the confounding factors. The procedures were done by a single surgeon at a single centre.\u003c/p\u003e \u003cp\u003eLimitations: It is not a randomised controlled study. The follow up period is short and therefore there is limited information on the long term outcomes. The stent dwell time was not analysed, and the rate of preoperative stenting was different between the two groups as 76% were pre-stented in group A, while only 36% were pre-stented in group B (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This is a limitation because the stent dwell time also is a risk factor for post operative fevers. The lithotripsy technique is not uniform between the two groups, as the end point was dust in group B, but fragments in group A, which could have had an impact on the operating time.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe suction incorporated ureteral access sheath is a revolutionary innovation which can optimise the outcomes of RIRS. Our results show a reduction in the need for auxiliary procedures and the incidence of post operative fever rates, with comparable overall complication rate and stone free rate. The improved endoscopic visibility is an added advantage. Thus suction incorporated flexible UAS seems to make a difference in RIRS.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eFunding: No funds, grants, or other support was received\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose\u003c/p\u003e\n\u003cp\u003eThe authors have no competing interests to declare that are relevant to the content of this article\u003c/p\u003e\n\u003cp\u003eEthics Approval: Obtained from our institutional ethics committee. Approval number : ECSTTH/EC Meet 05/2023/04\u003c/p\u003e\n\u003cp\u003eInformed consent was obtained from all individual participants included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution Statement:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCHANDRAMOHAN VADDI: Project development, Data collection, Manuscript editing\u003c/p\u003e\n\u003cp\u003eSOUNDARYA GANESAN: Data collection, Data analysis, Manuscript writing\u003c/p\u003e\n\u003cp\u003eRAMAKRISHNA PAIDAKULA: Data collection, Manuscript editing\u003c/p\u003e\n\u003cp\u003eSIDDALINGA SWAMY P M: Manuscript editing\u003c/p\u003e\n\u003cp\u003eHEMNATH ANANDAN: Manuscript editing\u003c/p\u003e\n\u003cp\u003eRAKESH PANDA: Manuscript editing\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eNone\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData cannot be shared openly but are available on request from authors\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSkolarikos A, Neisius A, Petř\u0026iacute;k A, Somani B, Thomas K, Gambaro G, Tzelves L (2022) Urolithiasis. 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J Endourol 30(9):992\u0026ndash;996. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1089/end.2016.0411\u003c/span\u003e\u003cspan address=\"10.1089/end.2016.0411\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePauchard F, Ventimiglia E, Corrales M, Traxer O (2022) A practical guide for intra-renal temperature and pressure management during RIRS: what is the evidence telling us. J Clin Med 11(12):3429. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/jcm11123429\u003c/span\u003e\u003cspan address=\"10.3390/jcm11123429\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDe Coninck, V., Somani, B., Sener, E. T., Emiliani, E., Corrales, M., Julieb\u0026oslash;-Jones,P., \u0026hellip; Keller, E. X. (2022). Ureteral access sheaths and its use in the future: a comprehensive update based on a literature review. Journal of Clinical Medicine, 11(17), 5128. https://doi.org/10.3390/jcm11175128\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Flexible ureteral access sheath, Retrograde intrarenal surgery, Thulium fibre laser, Suction","lastPublishedDoi":"10.21203/rs.3.rs-4496968/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4496968/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eAim:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe objective is to analyse the safety and efficacy of flexible ureteral access sheath (UAS) during retrograde intrarenal surgery in comparison with conventional ureteral access sheath.\u003c/p\u003e\n\u003cp\u003ePrimary aim: To compare the stone free rate (SFR), need for auxiliary procedure, complication rate. Secondary aim: To compare the operative time and intraoperative visibility\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBetween April and October 2023, prospectively collected data on RIRS using flexible UAS incorporated with suction (Group A, n=50) was matched with retrospective data on RIRS using conventional UAS (Group B, n=50), done by a single surgeon at a single centre. Demographic data and stone characteristics, intra operative and post operative parameters were collected from hospital database. Propensity matched analysis was done between the two groups after matching for stone size, volume and density.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe stone free rate (96% vs 92%, p = 0.678) and overall complication rate (22% vs 26%, p= 0.454) was comparable between the two groups. Group A patients had significantly better intraoperative visibility (100% vs 78% Grade 1 visibility, p\u0026lt;0.001), lesser need for auxiliary procedures (4% vs 16%, p=0.046), lesser incidence of post operative fever (4% vs 14%, p= 0.042) as compared to Group B. One patient in Group B required reintervention for steinstrasse after stent removal, while none in Group A required unplanned reintervention.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFlexible UAS with suction during RIRS is advantageous due to better intraoperative visibility, lesser need for auxiliary procedures and lesser infectious complications.\u003c/p\u003e","manuscriptTitle":"Flexible Ureteral Access Sheath with suction -– Does it make a difference in Retrograde intrarenal surgery?","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-14 18:44:34","doi":"10.21203/rs.3.rs-4496968/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":"8b97cfda-e572-4a5a-b333-5062f16f1575","owner":[],"postedDate":"June 14th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-06-23T11:02:08+00:00","versionOfRecord":[],"versionCreatedAt":"2024-06-14 18:44:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4496968","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4496968","identity":"rs-4496968","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}