A propensity scores matching analysis for treating renal stones 20-30mm with flexible ureteroscopy and laser lithotripsy

A propensity scores matching analysis for treating renal stones 20-30mm with flexible ureteroscopy and laser lithotripsy | 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 A propensity scores matching analysis for treating renal stones 20-30mm with flexible ureteroscopy and laser lithotripsy haitham abdalla shello This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5026953/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 Objectives: To assess the outcome of flexible ureterorenoscopy (F-URS) and LASER lithotripsy as a treatment modality for 2-3 cm renal stone. Patients and methods: 128 patients underwent F-URS for renal stones were enrolled. Seventy-five Patients had stone burden < 20mm were allocated to group I while 53 patients had stone burden 20-30mm were allocated to group II. A propensity score matching was implemented to match both groups. After matching, each group included 53 patients. Thereafter, both groups were compared according to stone free rate (SFR), needs for auxiliary procedure and complications. Results: After matching, the mean operating time in Group II was higher than that in group I p = 0.0176. No statistically significant difference in stone free rate between both groups 86.79% VS 75.47% p =0.693. There was a significant difference in need for a second session of RIRS between two groups (P=0.03). Conclusion: F-URS is a feasible treatment modality for stone 20-30mm. Need for another procedure and prolonged operative time should be taken into consideration. Urology & Nephrology renal stones flexible ureteroscopy laser lithotripsy Figures Figure 1 Introduction The development of a larger endoscope working channel and advancement of deflection mechanism has expanded diagnostic as well as therapeutic indications of flexible ureterorenoscopy. Evolution of Holmium:yttrium aluminium garnet (YAG) laser and expanding deflection angle facilitate wide utilisation of flexible uretoscope and enable fragmentation of larger and difficulty accessible stones. The standard treatment option for treating large renal stones ≥ 20 mm or complex renal calculi is percutaneous nephrolithotomy (PCNL) according to European and American guidelines because of its high successful rate [ 1 , 2 ]. However, poor medical condition, obesity and coagulopathies are a challenging situation for percutaneous renal intervention. The therapeutic gap between the superior overall outcome of PCNL and the minimal invasiveness of F-URS needs to be addressed through refinement of either techniques. Many authors [ 3 , 4 , 5 ] documented promising stone free rate of F-URS in treating large renal stone > 20mm with reasonable outcome however, the heterogeneity of studied cohort, due to variation in stone size and density, remains a major limitation. In our study, we tried to assess feasibility of F-URS as a treatment modality for large renal stones by matching the studied population. Patients and methods We conducted a retrospective cohort-based study for patients underwent flexible uretrorenoscopy and Holmium laser lithotripsy for renal stones. We obtained approval for this study from the local ethical authorities, and each patient signed an informed consent form. Patients are usually offered PCNL versus RIRS for renal stones 20-30mm. The possibility of repeated procedures and success rate are explained to the patients who agree for RIRS. Patients who have coagulopathy, BMI > 30 kg/m2, musculoskeletal deformity and multiple medical comorbidities are primarily offered F-URS. Study design: The study included patients who underwent flexible uretrorenoscopy for solitary or multiple renal stones, as determined by a preoperative non-contrast CT scan. Exclusion criteria were patient age's < 18 years old, renal anomalies (horseshoe kidney, pelvic kidney), ureteropelvic junction obstruction (UPJO), concomitant ipsilateral ureteral stone and past history of pyeloplasty or ureteral stricture. Patients are allocated to group I if they have renal stone burden < 20mm while those with a stone 20-30mm were assigned to group II. Initially, data in both groups were compared and statistically analyzed. A propensity score matching was applied in trying to match the groups to overcome the inherited difference then both groups were compared thereafter. Surgical technique: Routine preoperative laboratory inves t igations are carried out as well as non-contrast CT scans. A negative urine culture was a mandatory before clearance for F-URS. Before induction of anesthesia, 2 gram of 3rd generation cephalosporin is given as a prophylactic antibiotic. All procedures were performed with the Flex-X flexible ureteroscope. A 11/13 F ureteral access sheath was used for every patient. Lithotripsy was performed using a Holmium laser fiber 200 um. Holmium laser machine was set at 0.5-1.5J energy and firing a rate of 5–30 Hz according to the technique of lithotripsy used (dusting or fragmentation). Intraoperative clearance of stone fragments was assisted by use of stone basket and pumping system assisted irrigation through ureteral access sheath. In all patients, a Double-J ureteral stent was left in place postoperatively. postoperative Management: Patients were often admitted for an overnight stay to monitor vital signs and discharged on postoperative day 1 if no issues occurred such as frank hematuria, persistent loin pain or fever. Hospital stay was calculated from time of hospital admission till discharge time. Patients were scheduled for clinic visit after 2 weeks with KUB or ultrasound. If no residual fragments amenable for auxiliary procedure were detected, stent removal was decided at the same visit. Patients had sizable residual fragments ≤ 10 mm were scheduled for shock wave lithotripsy, while those had residuals > 10mm, were prepared for further session of F_URS. After 1 month of the last procedure, follow up low dose CT KUB was performed. Patients were declared stone free if there was no residual stones or the patient had insignificant residuals ≤ 2mm. Patients’ demographics, stone characteristics [longest diameter, locations within the kidney, Hounsfield unit (HU)], ASA score, preoperative hydronephrosis and preoperative DJ stent were recorded. Operative time, stone free rate and auxiliary procedures were recorded. The Clavien-Dindo classification was used to evaluate Postoperative complications. [ 6 ] Statistical analysis: SPSS 26.0 for windows was used to gather, tabulate, and analyse all data The mean, SD, and median (range) of quantitative data were used, while qualitative data were reported as absolute frequencies (number) and relative frequencies (percentage). To compare two sets of normally distributed data, the independent t-test was employed, whereas the Mann Whitney U test was used for non-normally distributed data. Chi-squared test was used to compare statistical difference of proportions for categorical variables. All of the tests were two-sided. P-values less than 0.05 were deemed statistically significant ; p-values greater than 0.05 were considered statistically insignificant Propensity score matching (PSM) is used to reduce the inherent disparity between the two groups of patients. Propensity scores were generated using a logistic regression model that included independent factors such as patient age, body mass index, and Housfield unit. To compensate for inherent differences, we used a match tolerance of 0.1 and the nearest neighbour point. After matching, perioperative characteristics, treatment outcome, and recorded complications were compared between the two groups. FUZZY extension 1.0.3 package incorporated into SPSS software was used to calculate PSM. Results Our retrospective analysis involved 128 patients diagnosed with renal stones who underwent flexible ureterorenoscopy and laser stone fragmentation. Seventy-five Patients had stones burden < 20mm were allocated to group I while 53 patients had stone burden 20-30mm were allocated to group II. Initially, a comparison between both groups showed significant statistical difference in patient age, BMI, stone density (Hounsfield unit) and stone size while other studied variables showed insignificant difference Table (1). Of the patients in group I, 18 had preoperative stenting, twelve for relieve of obstructive uropathy due to calculus impaction and 6 for inability to access upper urinary system. Nine patients of group II had preoperative stenting due to inability to access upper tract system. A model of logistic regression was constructed between independent variable patient age, BMI, Housfield unit and ASA score Table (2) Figure (1). Patients from each group were statistically analyzed after propensity score matching. Thereafter, each group included 53 patients. Between the new groups, there were no significant variations in the baseline characteristics of patients or stones. (Table 3). Afterwards, all the assessments were made between the new trails. After matching process (Table 3) , the mean postoperative hospital stay in both groups was (1.07 ± 0.26 vs 1.13 ± 0.34 days respectively, P = 0.08) which is statistically insignificant, while the mean operating times in Group II was higher than that in group I (86.67 ± 18.10 vs 94.52 ± 12.42 min, p = 0.0176), which showed statistically significant difference between two groups. There was no statistically significant difference in stone free rate between both groups (46 (86.79%) vs 40 (75.47%) p = 0.693. 7 patients (13.20%) in group I had documented residual stones, five of them (9.43%) requires second session RIRS and the remaining two patients (3.77%) underwent SWL. In group II, 13 patients (24.53%) had residual stones, a second session of RIRS is required for 10 (18.86%) patients and SWL is required for 3 (5.66%) patients. There was significant difference in need for second session of RIRS between two groups (P = 0.03). The stone free rate after second session of F-URS was 96.22% in group I VS 94.33% in group II without significant difference. According to the Clavien–Dindo classification, no major intraoperative complications were recorded in this study. Eleven (20.75%) patients experienced postoperative hematuria (Clavien I) in group I while, there were only 14(26.42%) in group II and all were resolved conservatively. According to urine culture tests, postoperative fever necessitating antibiotic medication was seen in four (7.54%) and five (9.43%) patients in groups I and II, respectively (grade II). There was no statistically significant difference in postoperative complications between groups. Results: Table (1): Before matching patients' demographics and clinical traits Items Group I Stone < 20mm ( n = 75) Group II Stone20-30mm ( n = 53) P value Sex ● Male ● Female 46(61.3%) 29(38.7%) 28(52.8%) 25(47.2%) b 0.337 Age (years) Median (IQR) 40.28 ± 14.26 37 (10) 33.89 ± 5.44 34 (8) c 0.007 BMI (kg/m2) 27.71 ± 5.85 30.17± 6.69 a 0.029 ASA score Median (IQR) 1.89 ± 0.78 2 (2) 1.87 ± 0.78 2 (2) c 0.853 Stone size (mm) 14.83 ± 2.12 26.30 ± 1.95 a 0.001 Hounsfield unit 733.67 ± 75.87 766.53 ± 47.88 a 0.005 Hydronephrosis n (%) ● Present ● Absent 15(20%) 60 (80%) 12(22.65%) 41(77.35%) b 0.718 Preoperative stent n (%) ● Yes ● No 18(27%) 57 (76%) 9 (17%) 44(83%) b 0.337 Operation side, n (%) ● Right ● Left 31(41.3%) 44 (58.7%) 19(35.84%) 34(64.16%) b 0.531 Stone location ● Pelvis ● Upper calyx ● Middle calyx ● Lower calyx 22(29.4%) 25(33.3%) 18(24%) 10(13.3%) 12(22.6%) 19(35.5%) 18(33.9%) 4 (7.6%) b 0.452 a Independent t-Test b Chi square test (X 2 ) c Mannwhitney test Table (2): logistic regression of the significant factors that were included in the matching process Factors B SE Wald Df Significance OR 95%CI Age -0.066 0.029 5.08 1 0.024 0.936 BMI 0.038 0.031 1.53 1 0.215 1.039 Hounsfield unit 0.006 0.003 3.20 1 0.073 1.006 Table (3): Patients’ demographics and clinical characteristics after matching Items Group I Stone ≤ 20mm ( n = 53) Group II Stone > 20mm ( n = 53) P value Sex n (%) ● Male ● Female 25 (47.2%) 28 (52.8%) 28(52.8%) 25(47.2%) b 0.560 Age (years) 35.51 ± 5.71 33.89 ± 5.44 a 0.138 BMI (kg/m2) 29.62 ± 5.67 30.17 ± 6.69 a 0.619 ASA score Median (IQR) 1.94 ± 0.79 2(2) 1.87 ± 0.785 2(2) c 0.623 Hounsfield unit 768.68 ± 46.22 76635 ± 47.88 a 0.814 Hydronephrosis n (%) ● Present ● Absent 15(28.3%) 38 (71.7%) 12(22.65%) 41(77.35%) b 0.503 Preoperative stent n (%) ● Yes ● No 11(20.7%) 42 (79.3%) 9(17%) 44(83%) b 0.619 Operation side, n (%) ● Right ● Left 22(41.5%) 31(58.5%) 19(35.8%) 34(64.2%) b 0.549 Stone location ● Pelvis ● Upper calyx ● Middle calyx ● Lower calyx 11(20.7%) 19(35.8%) 17(32.1%) 6(11.4%) 12(22.6%) 19(35.8%) 18(33.9%) 4(7.6%) b 0.924 a Independent t-Test b Chi square test (X 2 ) c Mannwhitney test Table (4): Patients’ outcome measures and complications after matching Items Group I Stone ≤ 20mm ( n = 53) Group II Stone > 20mm ( n = 53) P value Postoperative hospital stay (days) 1.07 ± 0.26 1.13 ± 0.34 a 0.08 Mean operative time (min) 86.67 ± 18.10 94.52 ± 12.42 a 0.0176 Initial Stone free rate 46 (86.80%) 40 (75.47%) b 0.693 Clavien-Dindo overall Complications, n (%) 15 (28.30%) 19 (35.85%) b 0.405 Clavien-Dindo Complications grade, n (%) Grade I Grade II 11(20.75%) 4 (7.54%) 14(26.42%) 5 (9.43%) b 0.981 Auxiliary procedures n (%) Second session RIRS n (%) SWL n (%) 7(13.20%) 5 (9.43%) 2 (3.77%) 13 (24.53%) 10 (18.86%) 3(5.66%) b 0.09 b 0.03 b 0.72 Final stone free rate post 2nd session RIRS 51(96.22%) 50(94.33%) b 0.92 a Independent t-Test b Chi square test (X 2 ) Discussion Urolithiasis is currently one of the most widespread urologic disorders with a rise in prevalence and recurrence [ 7 , 8 ]. Both American & European urological association recommended percutaneous nephrolithotomy as primary treatment modality for renal stones > 20mm. When PCNL is not amenable, large renal calculi > 2cm can be treated with flexible ureterorenoscopy or by shock wave lithotripsy or combination of both, but in these situations repeated session may be needed & long term follow up or DJ stenting may be required for long duration [ 9 , 10 , 11 ]. The balance between minimal invasiveness of F-URS and the higher success rate of PCNL should be taken in consideration in decision making [ 9 , 10 ]. In special situation as in obesity, coagulopathies or sever skeletal deformities, RIRS should be considered as a first choice for treating renal stones [ 12 ]. A group of investigators suggested that the indication of RIRS may be expanded to be the modality of choice for treating larger renal stones in special situations [ 13 ]. Many authors reported promising stone free rate following treating large stones with F-URS [3.4.5] . Hyams et al. reported using RIRS for renal stones treatment with diameters of 20-30mm in 120 patients [ 14 ]. They reported 63% stone free rate, when no residual or clinically insignificant fragments of < 2 mm were identified that is less than that of our research (94.33%). It may be attributed to using dusting technique in laser lithotripsy and irrigation pump during the procedure. Giusti et al. reported about 80% stone free rate for 316 patient treated with FURS with stone burden > 15mm after first session which is lower than that in our study post first session (86.8%) [ 15 ]. Their results post 2nd and 3rd session were 89.5% and 91.5% respectively but our results post second session were better and there was no need for 3rd session. They conclude that F-URS procedure is safe and effective, and a repeated session is needed to get better SFR for large renal calculi. Repeated procedures could be accompanied with increased SFR. Prabhakar [ 13 ] reported 100% SFR could be reached by single or staged sessions of FURS in their study on renal stones with diameter of 25 mm. Ben Saddik et al. in their study on renal stones 20–30 mm, found that SFR 89.3% post two-session of FURS and 97.1% after three sessions [ 16 ]. The higher SFR in our study could be due to combined dusting and extraction technique for laser lithotripsy. Treating large renal stones with RIRS would definitely be associated with prolonged OR time. In a mean operating duration of 83 minutes, Breda and coworkers[17 ] recorded 93% success with average stone size of 22 mm. In our study, we have comparable mean OR time 94 min. Mariani et al . reported mean operative time 64minutes(30-240minutes) for F-URS in dealing with 33mm stones [ 18 ] which is lower than to that in our study. The discrepancy in OR time may be explained by the variation of stone burden between different reports. Post URS urosepsis was reported in 3–5%, and its risk increased with an increase in stone size [ 19 ]. In our study, no patient developed urosepsis which may be due to routine use of ureteric access sheath that enables continuous lower intrarenal pressure. Our study is not devoid of limitations, we tried to overcome the selection bias by matching group before statistical analysis. However, a prospective randomised study on a large scale of patients would be helpful in deciding treatment modality for large renal stone. Conclusion Flexible uretrorenoscopy and laser stone disintegration is effective and safe treatment option for stone 20-30mm. Need for another procedure and prolongation of operative time should be taken in consideration and need to be discussed with patients. Declarations Conflict of Interest: All authors declare that they have no conflicting interests References Türk C, Skolarikos A, Neisius A, Petřík A, Seitz C, Thomas K (2019) European Association of Urology. Guidelines Office. Guidelines on urolithiasis Assimos D, Krambeck A, Miller NL, Monga M, Murad MH, Nelson CP, Pace KT, Pais VM, Pearle MS, Preminger GM, Razvi H (2016) Surgical management of stones: American urological association/endourological society guideline, PART I. J Urol 196(4):1153–1160 Breda A et al (2008) Flexible ureteroscopy and laser lithotripsy for single intrarenal stones 2 cm or greater—is this the new frontier? J Urol 179:981–984 Takazawa R, Kitayama S, Tsujii T (2012) Successful outcome of flexible ureteroscopy with holmium laser lithotripsy for renal stones 2 cm or greater. Int J Urol 19:264–267 Cohen J, Cohen S, Grasso M (2013) Ureteropyeloscopic treatment of large, complex intrarenal and proximal ureteral calculi. BJU Int 111:127–131 Dindo D, Demartines N, Clavien PA (2004) Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg 240:205–221 Hesse A, Brändle E, Wilbert D, Köhrmann KU, Alken P (2003) Study on the prevalence and incidence of urolithiasis in Germany comparing the years 1979 vs. 2000. Eur Urol 44(6):709–713 Sutherland JW, Parks JH, Coe FL (1985) Recurrence after a single renal stone in a community practice. Miner Electrolyte Metab 11(4):267–269 Assimos D, Krambeck A, Miller NL, Monga M, Murad MH, Nelson CP, Pace KT, Pais VM, Pearle MS, Preminger GM, Razvi H (2016) Surgical management of stones: American urological association/endourological society guideline, PART I. J Urol 196(4):1153–1160 Türk C, Neisius A, Petrik A, Seitz C, Skolarikos A, Thomas K (2018) EAU Guidelines on Urolithiasis. Eur Assoc Urol. :1–82 Grasso M, Conlin M, Bagley D (1998) Retrograde ureteropyeloscopic treatment of 2 cm. or greater upper urinary tract and minor Staghorn calculi. J Urol 160(2):346–351 Ishii H, Couzins M, Aboumarzouk O, Biyani CS, Somani BK (2016) Outcomes of systematic review of ureteroscopy for stone disease in the obese and morbidly obese population. J Endourol 30(2):135–145 Prabhakar M (2010) Retrograde ureteroscopic intrarenal surgery for large (1.6-3.5 cm) upper ureteric/renal calculus. Indian J Urol 26(1):46–49 Hyams ES, Munver R, Bird VG, Uberoi J, Shah O (2010) Flexible ureterorenoscopy and holmium laser lithotripsy for the management of renal stone burdens that measure 2 to 3 cm: a multi-institutional experience. J Endourol 24(10):1583–1588 Giusti G, Proietti S, Villa L, Cloutier J, Rosso M, Gadda GM, Doizi S, Suardi N, Montorsi F, Gaboardi F, Traxer O (2016) Current standard technique for modern flexible ureteroscopy: tips and tricks. Eur Urol 70(1):188–194 Ben MS, Al-Qahtani SS, Ndoye M, Gil-Diez-de-Medina S, Merlet B, Thomas A, Haab F, Traxer O (2011) Flexible ureteroscopy in the treatment of kidney stone between 2 and 3 cm. Progres en urologie: journal de l'Association francaise d'urologie et de la Societe francaise d'urologie. ;21(5):327 – 32 Breda A, Ogunyemi O, Leppert JT, Lam JS, Schulam PG (2008) Flexible ureteroscopy and laser lithotripsy for single intrarenal stones 2 cm or greater—is this the new frontier? J Urol 179(3):981–984 Mariani AJ (2004) Combined electrohydraulic and holmium: YAG laser ureteroscopic nephrolithotripsy for 20 to 40 mm renal calculi. J Urol 172(1):170–174 Riley JM, Stearman L, Troxel S (2009) Retrograde ureteroscopy for renal stones larger than 2.5 cm. J Endourol 23(9):1395 Additional Declarations The authors declare no competing interests. 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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Evolution of Holmium:yttrium aluminium garnet (YAG) laser and expanding deflection angle facilitate wide utilisation of flexible uretoscope and enable fragmentation of larger and difficulty accessible stones.\u003c/p\u003e \u003cp\u003eThe standard treatment option for treating large renal stones\u0026thinsp;\u0026ge;\u0026thinsp;20 mm or complex renal calculi is percutaneous nephrolithotomy (PCNL) according to European and American guidelines because of its high successful rate [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. However, poor medical condition, obesity and coagulopathies are a challenging situation for percutaneous renal intervention.\u003c/p\u003e \u003cp\u003eThe therapeutic gap between the superior overall outcome of PCNL and the minimal invasiveness of F-URS needs to be addressed through refinement of either techniques. Many authors [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] documented promising stone free rate of F-URS in treating large renal stone\u0026thinsp;\u0026gt;\u0026thinsp;20mm with reasonable outcome however, the heterogeneity of studied cohort, due to variation in stone size and density, remains a major limitation. In our study, we tried to assess feasibility of F-URS as a treatment modality for large renal stones by matching the studied population.\u003c/p\u003e"},{"header":"Patients and methods","content":"\u003cp\u003eWe conducted a retrospective cohort-based study for patients underwent flexible uretrorenoscopy and Holmium laser lithotripsy for renal stones. We obtained approval for this study from the local ethical authorities, and each patient signed an informed consent form.\u003c/p\u003e \u003cp\u003ePatients are usually offered PCNL versus RIRS for renal stones 20-30mm. The possibility of repeated procedures and success rate are explained to the patients who agree for RIRS. Patients who have coagulopathy, BMI\u0026thinsp;\u0026gt;\u0026thinsp;30 kg/m2, musculoskeletal deformity and multiple medical comorbidities are primarily offered F-URS.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design:\u003c/h2\u003e \u003cp\u003eThe study included patients who underwent flexible uretrorenoscopy for solitary or multiple renal stones, as determined by a preoperative non-contrast CT scan.\u003c/p\u003e \u003cp\u003eExclusion criteria were patient age's\u0026thinsp;\u0026lt;\u0026thinsp;18 years old, renal anomalies (horseshoe kidney, pelvic kidney), ureteropelvic junction obstruction (UPJO), concomitant ipsilateral ureteral stone and past history of pyeloplasty or ureteral stricture. Patients are allocated to group I if they have renal stone burden\u0026thinsp;\u0026lt;\u0026thinsp;20mm while those with a stone 20-30mm were assigned to group II. Initially, data in both groups were compared and statistically analyzed. A propensity score matching was applied in trying to match the groups to overcome the inherited difference then both groups were compared thereafter.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eSurgical technique:\u003c/h2\u003e \u003cp\u003eRoutine preoperative laboratory inves\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003et\u003c/span\u003eigations are carried out as well as non-contrast CT scans. A negative urine culture was a mandatory before clearance for F-URS. Before induction of anesthesia, 2 gram of 3rd generation cephalosporin is given as a prophylactic antibiotic.\u003c/p\u003e \u003cp\u003eAll procedures were performed with the Flex-X flexible ureteroscope. A 11/13 F ureteral access sheath was used for every patient. Lithotripsy was performed using a Holmium laser fiber 200 um. Holmium laser machine was set at 0.5-1.5J energy and firing a rate of 5\u0026ndash;30 Hz according to the technique of lithotripsy used (dusting or fragmentation). Intraoperative clearance of stone fragments was assisted by use of stone basket and pumping system assisted irrigation through ureteral access sheath. In all patients, a Double-J ureteral stent was left in place postoperatively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003epostoperative Management:\u003c/h2\u003e \u003cp\u003ePatients were often admitted for an overnight stay to monitor vital signs and discharged on postoperative day 1 if no issues occurred such as frank hematuria, persistent loin pain or fever. Hospital stay was calculated from time of hospital admission till discharge time.\u003c/p\u003e \u003cp\u003ePatients were scheduled for clinic visit after 2 weeks with KUB or ultrasound. If no residual fragments amenable for auxiliary procedure were detected, stent removal was decided at the same visit. Patients had sizable residual fragments\u0026thinsp;\u0026le;\u0026thinsp;10 mm were scheduled for shock wave lithotripsy, while those had residuals\u0026thinsp;\u0026gt;\u0026thinsp;10mm, were prepared for further session of F_URS. After 1 month of the last procedure, follow up low dose CT KUB was performed. Patients were declared stone free if there was no residual stones or the patient had insignificant residuals\u0026thinsp;\u0026le;\u0026thinsp;2mm.\u003c/p\u003e \u003cp\u003ePatients\u0026rsquo; demographics, stone characteristics [longest diameter, locations within the kidney, Hounsfield unit (HU)], ASA score, preoperative hydronephrosis and preoperative DJ stent were recorded. Operative time, stone free rate and auxiliary procedures were recorded. The Clavien-Dindo classification was used to evaluate Postoperative complications. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis:\u003c/h2\u003e \u003cp\u003e SPSS 26.0 for windows was used to gather, tabulate, and analyse all data The mean, SD, and median (range) of quantitative data were used, while qualitative data were reported as absolute frequencies (number) and relative frequencies (percentage).\u003c/p\u003e \u003cp\u003eTo compare two sets of normally distributed data, the independent t-test was employed, whereas the Mann Whitney U test was used for non-normally distributed data. Chi-squared test was used to compare statistical difference of proportions for categorical variables. All of the tests were two-sided. P-values less than 0.05 were deemed statistically significant ; p-values greater than 0.05 were considered statistically insignificant Propensity score matching (PSM) is used to reduce the inherent disparity between the two groups of patients. Propensity scores were generated using a logistic regression model that included independent factors such as patient age, body mass index, and Housfield unit. To compensate for inherent differences, we used a match tolerance of 0.1 and the nearest neighbour point. After matching, perioperative characteristics, treatment outcome, and recorded complications were compared between the two groups. FUZZY extension 1.0.3 package incorporated into SPSS software was used to calculate PSM.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eOur retrospective analysis involved 128 patients diagnosed with renal stones who underwent flexible ureterorenoscopy and laser stone fragmentation. Seventy-five Patients had stones burden\u0026thinsp;\u0026lt;\u0026thinsp;20mm were allocated to group I while 53 patients had stone burden 20-30mm were allocated to group II. Initially, a comparison between both groups showed significant statistical difference in patient age, BMI, stone density (Hounsfield unit) and stone size while other studied variables showed insignificant difference \u003cb\u003eTable\u0026nbsp;(1).\u003c/b\u003e\u003c/p\u003e \u003cp\u003eOf the patients in group I, 18 had preoperative stenting, twelve for relieve of obstructive uropathy due to calculus impaction and 6 for inability to access upper urinary system. Nine patients of group II had preoperative stenting due to inability to access upper tract system. A model of logistic regression was constructed between independent variable patient age, BMI, Housfield unit and ASA score \u003cb\u003eTable\u0026nbsp;(2) Figure (1).\u003c/b\u003e\u003c/p\u003e \u003cp\u003ePatients from each group were statistically analyzed after propensity score matching. Thereafter, each group included 53 patients. Between the new groups, there were no significant variations in the baseline characteristics of patients or stones. \u003cb\u003e(Table\u0026nbsp;3).\u003c/b\u003e Afterwards, all the assessments were made between the new trails.\u003c/p\u003e \u003cp\u003eAfter matching process \u003cb\u003e(Table\u0026nbsp;3)\u003c/b\u003e, the mean postoperative hospital stay in both groups was (1.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.26 vs 1.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34 days respectively, P\u0026thinsp;=\u0026thinsp;0.08) which is statistically insignificant, while the mean operating times in Group II was higher than that in group I (86.67\u0026thinsp;\u0026plusmn;\u0026thinsp;18.10 vs 94.52\u0026thinsp;\u0026plusmn;\u0026thinsp;12.42 min, p\u0026thinsp;=\u0026thinsp;0.0176), which showed statistically significant difference between two groups.\u003c/p\u003e \u003cp\u003eThere was no statistically significant difference in stone free rate between both groups (46 (86.79%) vs 40 (75.47%) p\u0026thinsp;=\u0026thinsp;0.693. 7 patients (13.20%) in group I had documented residual stones, five of them (9.43%) requires second session RIRS and the remaining two patients (3.77%) underwent SWL. In group II, 13 patients (24.53%)\u003c/p\u003e \u003cp\u003ehad residual stones, a second session of RIRS is required for 10 (18.86%) patients and SWL is required for 3 (5.66%) patients. There was significant difference in need for second session of RIRS between two groups (P\u0026thinsp;=\u0026thinsp;0.03). The stone free rate after second session of F-URS was 96.22% in group I VS 94.33% in group II without significant difference.\u003c/p\u003e \u003cp\u003eAccording to the Clavien\u0026ndash;Dindo classification, no major intraoperative complications were recorded in this study. Eleven (20.75%) patients experienced postoperative hematuria (Clavien I) in group I while, there were only 14(26.42%) in group II and all were resolved conservatively. According to urine culture tests, postoperative fever necessitating antibiotic medication was seen in four (7.54%) and five (9.43%) patients in groups I and II, respectively (grade II). There was no statistically significant difference in postoperative complications between groups.\u003c/p\u003e\n\u003ch3\u003eResults:\u003c/h3\u003e\n\u003cp\u003e \u003cb\u003eTable\u0026nbsp;(1): Before matching patients' demographics and clinical traits\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eItems\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGroup I\u003c/p\u003e \u003cp\u003eStone\u0026thinsp;\u0026lt;\u0026thinsp;20mm (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;75)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup II\u003c/p\u003e \u003cp\u003eStone20-30mm\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;53)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003cp\u003e● Male\u003c/p\u003e \u003cp\u003e● Female\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46(61.3%)\u003c/p\u003e \u003cp\u003e29(38.7%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28(52.8%)\u003c/p\u003e \u003cp\u003e25(47.2%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.337\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003cp\u003eMedian (IQR)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40.28\u0026thinsp;\u0026plusmn;\u0026thinsp;14.26\u003c/p\u003e \u003cp\u003e37 (10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33.89\u0026thinsp;\u0026plusmn;\u0026thinsp;5.44\u003c/p\u003e \u003cp\u003e34 (8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ec\u003c/sup\u003e \u003cb\u003e0.007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e27.71\u0026thinsp;\u0026plusmn;\u0026thinsp;5.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e30.17\u0026plusmn; 6.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003e \u003cb\u003e0.029\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eASA score\u003c/p\u003e \u003cp\u003eMedian (IQR)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.89\u0026thinsp;\u0026plusmn;\u0026thinsp;0.78\u003c/p\u003e \u003cp\u003e2 (2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.78\u003c/p\u003e \u003cp\u003e2 (2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003e\u003cb\u003ec\u003c/b\u003e\u003c/sup\u003e 0.853\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStone size (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e14.83\u0026thinsp;\u0026plusmn;\u0026thinsp;2.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e26.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHounsfield unit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e733.67\u0026thinsp;\u0026plusmn;\u0026thinsp;75.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e766.53\u0026thinsp;\u0026plusmn;\u0026thinsp;47.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003e \u003cb\u003e0.005\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHydronephrosis n (%)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e● Present\u003c/p\u003e \u003cp\u003e● Absent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15(20%)\u003c/p\u003e \u003cp\u003e60 (80%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12(22.65%)\u003c/p\u003e \u003cp\u003e41(77.35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e 0.718\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreoperative stent n (%)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e● Yes\u003c/p\u003e \u003cp\u003e● No\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18(27%)\u003c/p\u003e \u003cp\u003e57 (76%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (17%)\u003c/p\u003e \u003cp\u003e44(83%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e 0.337\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOperation side, n (%)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e● Right\u003c/p\u003e \u003cp\u003e● Left\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31(41.3%)\u003c/p\u003e \u003cp\u003e44 (58.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19(35.84%)\u003c/p\u003e \u003cp\u003e34(64.16%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e 0.531\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStone location\u003c/b\u003e\u003c/p\u003e \u003cp\u003e● Pelvis\u003c/p\u003e \u003cp\u003e● Upper calyx\u003c/p\u003e \u003cp\u003e● Middle calyx\u003c/p\u003e \u003cp\u003e● Lower calyx\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22(29.4%)\u003c/p\u003e \u003cp\u003e25(33.3%)\u003c/p\u003e \u003cp\u003e18(24%)\u003c/p\u003e \u003cp\u003e10(13.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12(22.6%)\u003c/p\u003e \u003cp\u003e19(35.5%)\u003c/p\u003e \u003cp\u003e18(33.9%)\u003c/p\u003e \u003cp\u003e4 (7.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e 0.452\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003ea\u003c/sup\u003e \u003cb\u003eIndependent t-Test\u003c/b\u003e \u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eChi square test (X\u003c/b\u003e\u003csup\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e \u003csup\u003e\u003cb\u003ec\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eMannwhitney test\u003c/b\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;(2): logistic regression of the significant factors that were included in the matching process\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFactors\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eWald\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eDf\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSignificance\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eOR 95%CI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.066\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.936\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBMI\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.038\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.031\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.215\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.039\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHounsfield unit\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.006\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.073\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.006\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;(3): Patients\u0026rsquo; demographics and clinical characteristics after matching\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabc\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eItems\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGroup I\u003c/p\u003e \u003cp\u003eStone\u0026thinsp;\u0026le;\u0026thinsp;20mm (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;53)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup II\u003c/p\u003e \u003cp\u003eStone\u0026thinsp;\u0026gt;\u0026thinsp;20mm\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;53)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex n (%)\u003c/p\u003e \u003cp\u003e● Male\u003c/p\u003e \u003cp\u003e● Female\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25 (47.2%)\u003c/p\u003e \u003cp\u003e28 (52.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28(52.8%)\u003c/p\u003e \u003cp\u003e25(47.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.560\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e35.51\u0026thinsp;\u0026plusmn;\u0026thinsp;5.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e33.89\u0026thinsp;\u0026plusmn;\u0026thinsp;5.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003e 0.138\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e29.62\u0026thinsp;\u0026plusmn;\u0026thinsp;5.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e30.17\u0026thinsp;\u0026plusmn;\u0026thinsp;6.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003e 0.619\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eASA score\u003c/p\u003e \u003cp\u003eMedian (IQR)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.94\u0026thinsp;\u0026plusmn;\u0026thinsp;0.79\u003c/p\u003e \u003cp\u003e2(2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.785\u003c/p\u003e \u003cp\u003e2(2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ec\u003c/sup\u003e 0.623\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHounsfield unit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e768.68\u0026thinsp;\u0026plusmn;\u0026thinsp;46.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e76635\u0026thinsp;\u0026plusmn;\u0026thinsp;47.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003e 0.814\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHydronephrosis n (%)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e● Present\u003c/p\u003e \u003cp\u003e● Absent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15(28.3%)\u003c/p\u003e \u003cp\u003e38 (71.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12(22.65%)\u003c/p\u003e \u003cp\u003e41(77.35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e 0.503\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreoperative stent n (%)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e● Yes\u003c/p\u003e \u003cp\u003e● No\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11(20.7%)\u003c/p\u003e \u003cp\u003e42 (79.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9(17%)\u003c/p\u003e \u003cp\u003e44(83%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e 0.619\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOperation side, n (%)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e● Right\u003c/p\u003e \u003cp\u003e● Left\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22(41.5%)\u003c/p\u003e \u003cp\u003e31(58.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19(35.8%)\u003c/p\u003e \u003cp\u003e34(64.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.549\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStone location\u003c/b\u003e\u003c/p\u003e \u003cp\u003e● Pelvis\u003c/p\u003e \u003cp\u003e● Upper calyx\u003c/p\u003e \u003cp\u003e● Middle calyx\u003c/p\u003e \u003cp\u003e● Lower calyx\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11(20.7%)\u003c/p\u003e \u003cp\u003e19(35.8%)\u003c/p\u003e \u003cp\u003e17(32.1%)\u003c/p\u003e \u003cp\u003e6(11.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12(22.6%)\u003c/p\u003e \u003cp\u003e19(35.8%)\u003c/p\u003e \u003cp\u003e18(33.9%)\u003c/p\u003e \u003cp\u003e4(7.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.924\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003ea\u003c/sup\u003e \u003cb\u003eIndependent t-Test\u003c/b\u003e \u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eChi square test (X\u003c/b\u003e\u003csup\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e \u003csup\u003e\u003cb\u003ec\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eMannwhitney test\u003c/b\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;(4): Patients\u0026rsquo; outcome measures and complications after matching\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabd\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eItems\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGroup I\u003c/p\u003e \u003cp\u003eStone\u0026thinsp;\u0026le;\u0026thinsp;20mm (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;53)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup II\u003c/p\u003e \u003cp\u003eStone\u0026thinsp;\u0026gt;\u0026thinsp;20mm\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;53)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative hospital stay (days)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003e 0.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean operative time (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e86.67\u0026thinsp;\u0026plusmn;\u0026thinsp;18.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e94.52\u0026thinsp;\u0026plusmn;\u0026thinsp;12.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003e \u003cb\u003e0.0176\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial Stone free rate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46 (86.80%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e40 (75.47%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.693\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClavien-Dindo overall Complications,\u003c/p\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (28.30%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (35.85%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.405\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClavien-Dindo Complications grade,\u003c/p\u003e \u003cp\u003en (%)\u003c/p\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11(20.75%)\u003c/p\u003e \u003cp\u003e4 (7.54%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14(26.42%)\u003c/p\u003e \u003cp\u003e5 (9.43%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.981\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAuxiliary procedures n (%)\u003c/p\u003e \u003cp\u003eSecond session RIRS n (%)\u003c/p\u003e \u003cp\u003eSWL n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7(13.20%)\u003c/p\u003e \u003cp\u003e5 (9.43%)\u003c/p\u003e \u003cp\u003e2 (3.77%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (24.53%)\u003c/p\u003e \u003cp\u003e10 (18.86%)\u003c/p\u003e \u003cp\u003e3(5.66%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.09\u003c/p\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e \u003cb\u003e0.03\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.72\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal stone free rate post 2nd session RIRS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51(96.22%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50(94.33%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003eb\u003c/sup\u003e 0.92\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003ea\u003c/sup\u003e \u003cb\u003eIndependent t-Test\u003c/b\u003e\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eChi square test (X\u003c/b\u003e\u003csup\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eUrolithiasis is currently one of the most widespread urologic disorders with a rise in prevalence and recurrence [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Both American \u0026amp; European urological association recommended percutaneous nephrolithotomy as primary treatment modality for renal stones\u0026thinsp;\u0026gt;\u0026thinsp;20mm. When PCNL is not amenable, large renal calculi\u0026thinsp;\u0026gt;\u0026thinsp;2cm can be treated with flexible ureterorenoscopy or by shock wave lithotripsy or combination of both, but in these situations repeated session may be needed \u0026amp; long term follow up or DJ stenting may be required for long duration [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe balance between minimal invasiveness of F-URS and the higher success rate of PCNL should be taken in consideration in decision making [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In special situation as in obesity, coagulopathies or sever skeletal deformities, RIRS should be considered as a first choice for treating renal stones [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. A group of investigators suggested that the indication of RIRS may be expanded to be the modality of choice for treating larger renal stones in special situations [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMany authors reported promising stone free rate following treating large stones with F-URS \u003cb\u003e[3.4.5]\u003c/b\u003e. \u003cb\u003eHyams et al.\u003c/b\u003e reported using RIRS for renal stones treatment with diameters of 20-30mm in 120 patients [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. They reported 63% stone free rate, when no residual or clinically insignificant fragments of \u0026lt;\u0026thinsp;2 mm were identified that is less than that of our research (94.33%). It may be attributed to using dusting technique in laser lithotripsy and irrigation pump during the procedure. \u003cb\u003eGiusti et al.\u003c/b\u003e reported about 80% stone free rate for 316 patient treated with FURS with stone burden\u0026thinsp;\u0026gt;\u0026thinsp;15mm after first session which is lower than that in our study post first session (86.8%) [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Their results post 2nd and 3rd session were 89.5% and 91.5% respectively but our results post second session were better and there was no need for 3rd session. They conclude that F-URS procedure is safe and effective, and a repeated session is needed to get better SFR for large renal calculi.\u003c/p\u003e \u003cp\u003eRepeated procedures could be accompanied with increased SFR. Prabhakar [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] reported 100% SFR could be reached by single or staged sessions of FURS in their study on renal stones with diameter of 25 mm. \u003cb\u003eBen Saddik et al.\u003c/b\u003e in their study on renal stones 20\u0026ndash;30 mm, found that SFR 89.3% post two-session of FURS and 97.1% after three sessions [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The higher SFR in our study could be due to combined dusting and extraction technique for laser lithotripsy.\u003c/p\u003e \u003cp\u003eTreating large renal stones with RIRS would definitely be associated with prolonged OR time. In a mean operating duration of 83 minutes, Breda and coworkers[17 ] recorded 93% success with average stone size of 22 mm. In our study, we have comparable mean OR time 94 min. \u003cb\u003eMariani et al\u003c/b\u003e. reported mean operative time 64minutes(30-240minutes) for F-URS in dealing with 33mm stones [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] which is lower than to that in our study. The discrepancy in OR time may be explained by the variation of stone burden between different reports.\u003c/p\u003e \u003cp\u003ePost URS urosepsis was reported in 3\u0026ndash;5%, and its risk increased with an increase in stone size [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In our study, no patient developed urosepsis which may be due to routine use of ureteric access sheath that enables continuous lower intrarenal pressure. Our study is not devoid of limitations, we tried to overcome the selection bias by matching group before statistical analysis. However, a prospective randomised study on a large scale of patients would be helpful in deciding treatment modality for large renal stone.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eFlexible uretrorenoscopy and laser stone disintegration is effective and safe treatment option for stone 20-30mm. Need for another procedure and prolongation of operative time should be taken in consideration and need to be discussed with patients.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflict of Interest:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors declare that they have no conflicting interests\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eT\u0026uuml;rk C, Skolarikos A, Neisius A, Petř\u0026iacute;k A, Seitz C, Thomas K (2019) European Association of Urology. Guidelines Office. Guidelines on urolithiasis\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAssimos D, Krambeck A, Miller NL, Monga M, Murad MH, Nelson CP, Pace KT, Pais VM, Pearle MS, Preminger GM, Razvi H (2016) Surgical management of stones: American urological association/endourological society guideline, PART I. J Urol 196(4):1153\u0026ndash;1160\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBreda A et al (2008) Flexible ureteroscopy and laser lithotripsy for single intrarenal stones 2 cm or greater\u0026mdash;is this the new frontier? J Urol 179:981\u0026ndash;984\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTakazawa R, Kitayama S, Tsujii T (2012) Successful outcome of flexible ureteroscopy with holmium laser lithotripsy for renal stones 2 cm or greater. Int J Urol 19:264\u0026ndash;267\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCohen J, Cohen S, Grasso M (2013) Ureteropyeloscopic treatment of large, complex intrarenal and proximal ureteral calculi. BJU Int 111:127\u0026ndash;131\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDindo D, Demartines N, Clavien PA (2004) Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg 240:205\u0026ndash;221\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHesse A, Br\u0026auml;ndle E, Wilbert D, K\u0026ouml;hrmann KU, Alken P (2003) Study on the prevalence and incidence of urolithiasis in Germany comparing the years 1979 vs. 2000. Eur Urol 44(6):709\u0026ndash;713\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSutherland JW, Parks JH, Coe FL (1985) Recurrence after a single renal stone in a community practice. Miner Electrolyte Metab 11(4):267\u0026ndash;269\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAssimos D, Krambeck A, Miller NL, Monga M, Murad MH, Nelson CP, Pace KT, Pais VM, Pearle MS, Preminger GM, Razvi H (2016) Surgical management of stones: American urological association/endourological society guideline, PART I. J Urol 196(4):1153\u0026ndash;1160\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eT\u0026uuml;rk C, Neisius A, Petrik A, Seitz C, Skolarikos A, Thomas K (2018) EAU Guidelines on Urolithiasis. Eur Assoc Urol. :1\u0026ndash;82\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrasso M, Conlin M, Bagley D (1998) Retrograde ureteropyeloscopic treatment of 2 cm. or greater upper urinary tract and minor Staghorn calculi. J Urol 160(2):346\u0026ndash;351\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIshii H, Couzins M, Aboumarzouk O, Biyani CS, Somani BK (2016) Outcomes of systematic review of ureteroscopy for stone disease in the obese and morbidly obese population. J Endourol 30(2):135\u0026ndash;145\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrabhakar M (2010) Retrograde ureteroscopic intrarenal surgery for large (1.6-3.5 cm) upper ureteric/renal calculus. Indian J Urol 26(1):46\u0026ndash;49\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHyams ES, Munver R, Bird VG, Uberoi J, Shah O (2010) Flexible ureterorenoscopy and holmium laser lithotripsy for the management of renal stone burdens that measure 2 to 3 cm: a multi-institutional experience. J Endourol 24(10):1583\u0026ndash;1588\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGiusti G, Proietti S, Villa L, Cloutier J, Rosso M, Gadda GM, Doizi S, Suardi N, Montorsi F, Gaboardi F, Traxer O (2016) Current standard technique for modern flexible ureteroscopy: tips and tricks. Eur Urol 70(1):188\u0026ndash;194\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBen MS, Al-Qahtani SS, Ndoye M, Gil-Diez-de-Medina S, Merlet B, Thomas A, Haab F, Traxer O (2011) Flexible ureteroscopy in the treatment of kidney stone between 2 and 3 cm. Progres en urologie: journal de l'Association francaise d'urologie et de la Societe francaise d'urologie. ;21(5):327\u0026thinsp;\u0026ndash;\u0026thinsp;32\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBreda A, Ogunyemi O, Leppert JT, Lam JS, Schulam PG (2008) Flexible ureteroscopy and laser lithotripsy for single intrarenal stones 2 cm or greater\u0026mdash;is this the new frontier? J Urol 179(3):981\u0026ndash;984\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMariani AJ (2004) Combined electrohydraulic and holmium: YAG laser ureteroscopic nephrolithotripsy for 20 to 40 mm renal calculi. J Urol 172(1):170\u0026ndash;174\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRiley JM, Stearman L, Troxel S (2009) Retrograde ureteroscopy for renal stones larger than 2.5 cm. J Endourol 23(9):1395\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"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":"renal stones, flexible ureteroscopy, laser lithotripsy","lastPublishedDoi":"10.21203/rs.3.rs-5026953/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5026953/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cem\u003e\u003cstrong\u003eObjectives:\u0026nbsp;\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eTo assess the outcome of flexible ureterorenoscopy (F-URS) and LASER lithotripsy as a treatment modality for 2-3 cm renal stone.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003ePatients and methods:\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e128 patients underwent F-URS for renal stones were enrolled. Seventy-five Patients had stone burden \u0026lt; 20mm were allocated to group I while 53 patients had stone burden 20-30mm were allocated to group II. A propensity score matching was implemented to match both groups. After matching, each group included 53 patients. Thereafter, both groups were compared according to stone free rate (SFR), needs for auxiliary procedure and complications.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eResults:\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAfter matching, the mean operating time in Group II was higher than that in group I p = 0.0176. No statistically significant difference in stone free rate between both groups 86.79% VS 75.47% p =0.693. There was a significant difference in need for a second session of RIRS between two groups (P=0.03).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eF-URS is a feasible treatment modality for stone 20-30mm. Need for another procedure and prolonged operative time should be taken into consideration.\u003c/p\u003e","manuscriptTitle":"A propensity scores matching analysis for treating renal stones 20-30mm with flexible ureteroscopy and laser lithotripsy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-09-04 21:23:54","doi":"10.21203/rs.3.rs-5026953/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":"c9d935c1-72c3-4127-a29a-8adad36e6136","owner":[],"postedDate":"September 4th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":37053998,"name":"Urology \u0026 Nephrology"}],"tags":[],"updatedAt":"2024-09-04T21:23:54+00:00","versionOfRecord":[],"versionCreatedAt":"2024-09-04 21:23:54","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5026953","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5026953","identity":"rs-5026953","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}