Comparison of Standard percutaneous nephrolithotomy with and without Flexible Nephroscopy in Complex Renal Stones

Comparison of Standard percutaneous nephrolithotomy with and without Flexible Nephroscopy in Complex Renal Stones | 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 Comparison of Standard percutaneous nephrolithotomy with and without Flexible Nephroscopy in Complex Renal Stones hasanain Al-tamimi, saif mohammed, mohammed ismail This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8988222/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Background Complex renal stones (CRS) continue to be challenging in percutaneous nephrolithotomy (PCNL). Flexible nephroscopy (FN) may enhance intrarenal inspection and outcomes. Objective To compare standard PCNL versus PCNL with FN in patients with CRS regarding operative parameters, bleeding profile, postoperative pain, hospital stay, and residual stones. Patients and Methods: This is a prospective comparative single-center study including 72 patients with CRS treated at Ghazi Al-Hariri Hospital for Surgical Specialities. Patients were assigned into two groups according to surgical management: standard PCNL (n = 40) and PCNL with FN (n = 32). Operative time, fluoroscopy time, number of access tracts, blood loss, perioperative hemoglobin, pain score at 6 and 24 hours post-surgery, analgesia requirement, hospital stay, and residual stones at 1 week and 3 months were reported. Results Operative time and fluoroscopy time were significantly longer in the PCNL with FN group (112.0 ± 22.55 vs 93.23 ± 14.16 min; 7.98 ± 1.59 vs 6.19 ± 0.34 min). The standard PCNL group needed more multiple tracts (three tracts: 17.5% vs 0%). Estimated blood loss was significantly lower in PCNL with FN (248.16 ± 42.25 vs 274.1 ± 37.09 mL). Although preoperative hemoglobin (Hb) was comparable, postoperative Hb was significantly higher in the PCNL with FN group (12.13 ± 1.51 vs 11.54 ± 0.96 g/dL) with a smaller Hb dropping (0.91 ± 0.57 vs 1.71 ± 0.69 g/dL). Pain at 24-hour post-surgery was significantly lower in PCNL with FN (3.25 ± 0.76 vs 4.08 ± 0.94), and there were fewer patients required analgesia (34.38% vs 60%, p = 0.031). Furthermore, hospital stay was significantly shorter in PCNL with FN (2.75 ± 1.34 vs 4.0 ± 1.83 days). In contrast, residual stone was comparable between the two groups at 1 week and 3 months postoperatively with no significant differences Conclusion In CRS, adding FN to PCNL was associated with longer operative and fluoroscopy times, but it reduces access tracts, 24-hour postoperative pain and analgesia requirement, improves the bleeding profile, and shortened hospital stay, without a significant difference in residual stone rates up to 3 months. Complex renal stones Percutaneous nephrolithotomy Flexible nephroscopy Residual stone Introduction Complex renal stones (CRS) are a challenging type in the classification of renal stones, characterized by high stone burden, distribution in various calices, urinary tract infection (UTI) and renal dysfunction [ 1 , 2 ]. Surgery remains the cornerstone treatment for CRS. The traditional surgical method is percutaneous nephrolithotomy (PCNL) [ 3 ]. PCNL has several advantages including small trauma, high removal rate of lithotripsy and low incidence of postoperative complications [ 4 ]. Current recommendation steadily consider PCNL as the primary choice for treatment of renal stone exceeding 2 cm as well as for complex conformations such as staghorn calculi, where the stone size and complex anatomy often restrict the efficiency of retrograde approaches [ 5 ]. Despite the high effectiveness of PCNL, CRS remains challenging as the complete clearance is frequently restricted by calyceal anatomy, access angle, and the occurrence of wreckages in calyces away from the percutaneous tract [ 6 ]. Residual fragments are important form clinical point of view regardless of their size, because they can act as a focus for regrowth, persistent symptoms, and microbial infection. Furthermore, there usually a need for additional procedures or reintervention [ 7 ]. These issues have augmented the interest in techniques that may improve intrarenal view at the end of PCNL to distinguish and eliminate missed fragments. Flexible nephroscopy (FN) achieved through the percutaneous tract after standard PCNL has been suggested as a practical technique to visualize and remove stone fragments situated in less accessible calyces with no need to create additional tracts [ 8 ]. Clinical comparative investigations have testified that adding routine FN to PCNL can increase stone-free rates (SFR) and reduce the necessity for reinterventions, especially in patients with large or CRS, although potential disadvantages include longer operative time and more equipment requirements [ 9 ]. However, remains unclear whether adding FN to standard PCNL provides a meaningful reduction for ancillary procedures without increasing operative time, bleeding, postoperative pain, or hospital stay. Therefore, the present study was conducted to compare the perioperative and stone-clearance outcomes of standard PCNL performed with versus PCNL with FN in patients with complex renal stones Patients and Methods This study is a prospective comparative single-center study encompassing 72 consecutive patients diagnosed with CRS and scheduled for PCNL at Ghazi Al-Hariri Hospital for Surgical Specialities from January to December 2025. Eligible patients were those having any pelvic calculus and/or inferior CRS. On the other hand, pediatric patients, morbid obese, those with a history of shockwave lithotripsy (SWL), coagulopathies, or congenital anomalies of the urinary tract were excluded from the study. Following a full history-taking and clinical evaluation, all patients underwent renal ultrasound, X-ray imaging of the kidneys, ureters, and bladder (KUB), non-contrast computed tomography (NCCT) of the KUB, alongside a series of blood investigations including complete blood count, renal function tests, serum electrolytes, and coagulation profile, in addition to urine microscopy. The study received approval from the Iraqi Boad for Medical Specializations ( date, and a written informed consent was obtained from each participant. Study groups and data collection Patients were divided into two groups according to surgical management: 40 patients managed by standard PCNL alone, and 32 patients were managed by PCNL with FN. Demographic characteristics including age, sex, affected site, and stone size were collected form all patients before operation. Surgical Technique All procedures were performed under general anesthesia. Patients were initially placed in the lithotomy position for cystoscopy. A 5–6 Fr open-ended ureteral catheter was entered into the renal pelvis under fluoroscopic guidance, while a Foley catheter was inserted for bladder drainage. Percutaneous renal access was obtained under fluoroscopic guidance using an 18-gauge access needle, aiming for a posterior calyx to achieve a straight tract to the stone-bearing calyx while minimizing vascular injury. A 0.035-inch guidewire was inserted into the collecting system, preferably coiled within the renal pelvis. Tract dilation was performed using a balloon dilator up to the desired size, followed by placement of an Amplatz sheath. Nephroscopy was performed using a rigid nephroscope. Stone fragmentation was achieved with ultrasonic lithotripsy, and fragments were evacuated using graspers and suction through the sheath. In cases of stones distributed in multiple calyces or with unfavorable angles, additional percutaneous tracts were created as required to optimize access and clearance. In the standard PCNL group, stone clearance was assessed using rigid nephroscopy and fluoroscopy. At the end of the procedure, the collecting system was inspected through the rigid nephroscope and fluoroscopy was used to evaluate for residual fragments. In the PCNL with FN group, after completion of rigid nephroscopy and fragment extraction, a flexible nephroscope was introduced through the Amplatz sheath to systematically inspect the renal pelvis and all accessible calyces. Residual fragments identified by flexible inspection were extracted using a nitinol basket and/or relocated to an accessible calyx for fragmentation and removal. Final assessment of stone clearance was performed with combined endoscopic visualization and fluoroscopy in both groups. At the end of the procedure, a nephrostomy tube and/or ureteral stent was placed based on intraoperative findings. Nephrostomy and ureteral catheters were removed once urine output was clear. Operative time, fluoroscopy time, stone size, number of access, residual stone, blood loss (in mL) and blood transfusion were recorded during the operation. Visual analogue scale (VAS) was used to evaluate pain at 6 hrs and 24 hrs postoperatively. Need for analgesia during 6hr and 24hr post- surgery was also calculated. Patients were followed up for 3 months after operation during which the hospital stay and residual stone at 1 week and 3 months post-surgery were evaluated. Residual stone was defined as the presence of any detectable fragment within the collecting system on postoperative imaging using NCCT or a combination of KUB and ultrasound depending on stone radiopacity and local availability. Statistical analysis The Statistical Package for Social Science (SPSS) version 25 was used to analyze these data. Quantitative data were expressed as mean and standard deviation with independent t-test was used for group comparison. Qualitative data were expressed and number and percentage and the Chi-square test (χ2-value) was used for comparison. A p-value of less than 0.05 was considered significant. Results Demographic characteristics of the patients The mean age of the patients in standard PCNL was 45.58±7.59 years compared with 47.53±7.0 years in PCNL with FN group with no significant difference. Similarly, the two groups were comparable in sex distribution, affected side and stone size with no significant differences (Table 1) Table 1: Demographic characteristics of the patients Variables Standard PCNL (n= 40) PCNL with FN (n=32) p-value Age, years Mean± SD Range 45.58±7.59 35-62 47.53±7.0 35-60 0.264 Sex Male Female 26(65%) 14(35%) 21(65.63%) 11(34.37%) 0.956 Affected side Right Left 23(57.5%) 17(42.5%) 20(%62.5) 12(37.5%) 0.667 Stone size, mm Mean± SD Range 4.53±2.07 2-9 4.64±2.06 2-8.5 0.823 SD: standard deviation, PCNL: percutaneous nephrolithotomy, FN: flexible nephroscopy Interoperative characteristics Most intraoperative characteristics varied significantly between the two groups. The mean operative and fluoroscopy times in PCNL group was 93.23±14.16 min and 6.19±0.34 min, respectively which were shorter than that in PCNL with FN group (112.0-22.55 min and 7.98±1.59 min, respectively with significant differences (p<0.001 for both). Furthermore, most patients (56.25%) in the standard PCNL with FN group were treated with a single tract, and none required three tracts, whereas patients in standard PCNL group more frequently required multiple tracts, including three accesses in 17.5% of cases, with a significant difference (p<0.001). Finally, estimated blood loss was significantly lower in the PCLN with FN group (248.16±42.25mL) compared with the standard PCNL group (274.1±37.09 mL) (p=0.007) as shown in table 2. Table 2: Intraoperative characteristics of the patients Variables Standard PCNL (n= 40) PCNL with FN (n=32) p-value Operative time, min Mean± SD Range 93.23±14.16 70-140 112.0-22.55 70-160 <0.001 Fluoroscopy time, min Mean± SD Range 6.19±0.34 5.7-7 7.98±1.59 5.4-12 <0.001 Number of access 1 2 3 17(42.5%) 16(40%) 7(17.5%) 18(56.25%) 14(43.75%) 0(0%) 0.042 Blood loss, ml Mean± SD Range 274.1±37.09 200-350 248.16±42.25 185-335 0.007 SD: standard deviation, PCNL: percutaneous nephrolithotomy, FN: flexible nephroscopy Perioperative hemoglobin concentration Preoperatively, standard PCNL and PCNL with FN displayed almost similar concentration of Hb concentration with no significant difference. However, postoperative Hb concentration was significantly higher in PCNL with FN group (12.13±1.51 g/dL) compared with the standard PCNL group (11.54±0.96 g/dL) (p=0.047). Accordingly, the calculated Hb drop was significantly smaller in patients undergone PCNL with FN group (0.91±0.57 g/dL) than in those who had standard PCNL (1.71±0.69 g/dL) (p<0.001) as shown in table 3 Table 3: Perioperative hemoglobin and intraoperative blood loss Variables Standard PCNL (n= 40) PCNL with FN (n=32) p-value Preoperative Hb, g/dl Mean± SD Range 13.25±1.34 10.4-15.7 13.04±1.42 10.3-15.0 0.518 Postoperative Hb, g/dl Mean± SD Range 11.54±0.96 9.2-13.1 12.13±1.51 9.1-14.9 0.047 Hb difference, g/dl Mean± SD Range 1.71±0.69 0.8-4.0 0.91±0.57 0.2-2.1 <0.001 SD: standard deviation, Hb: hemoglobin, PCNL: percutaneous nephrolithotomy, FN: flexible nephroscopy Postoperative findings Early postoperative pain at 6 hours, assessed by VAS, was similar between groups, with no significant difference. However, by 24 hours post-surgery, pain scores were significantly lower in the PCNL with FN group (3.25±0.76) compared to standard PCNL group (4.08±0.94) (p<0.001). As a consequence, a greater proportion of patients in the standard PCNL group required postoperative analgesia (60%) compared with the PCNL with FN group (34.38%) (p=0.031). Furthermore, the PCNL with FN group had a significantly shorter hospital stay (2.75±1.34 days) than those in the standard PCNL group (4.0±1.83 days)(p=0.002). Regrading residual stone, it was generally comparable between the two groups whether one week or three months postoperatively with no significant differences (Table 4). Table 4: Postoperative findings Variables Standard PCNL (n= 40) PCNL with FN (n=32) p-value VAS at 6h postop Mean± SD Range 5.5±1.32 3-8 5.03±1.51 2-8 0.165 VAS at 24h postop Mean± SD Range 4.08±0.94 3-6 3.25±0.76 2-5 <0.001 Residual stone, 1 week postop No Yes 33(82.5%) 7(17.5%) 28(87.5%) 4(12.5%) 0.558 Residual stone, 3 months postop No Yes 36(90%) 4(10%) 30(93.75%) 2(6.25%) 0.567 Need for analgesia No Yes 16(40%) 24(60%) 21(65.62%) 11(34.38%) 0.031 Hospital stay, days Mean± SD Range 4.0±1.83 2-8 2.75±1.34 1-6 0.002 SD: standard deviation , VAS: visual analogue scale, PCNL: percutaneous nephrolithotomy, FN: flexible nephroscopy Discussion The present study aimed to compare standard PCNL versus PCNL with FN in patients with CRS regarding operative parameters, bleeding profile, postoperative pain, hospital stay, and residual stones. According to the result of the study, adding FN to PCNL significantly increased both operative time and fluoroscopy time compared with standard PCNL. These results are consistent with many previous studies worldwide. Goktug et al. [ 10 ] in a comparative study of standard PCNL versus PCNL combined with intraoperative antegrade FN for staghorn stones, reported longer operating time in the flexible-nephroscopy arm (about 113 min versus 95 min in standard PCNL) and also noted significantly higher fluoroscopy time with the addition of flexible nephroscopy, which aligns closely with the direction and magnitude of delay observed in the present study. Similarly, Masood et al. [ 8 ] reported that incorporating intraoperative FN during PCNL significantly increased operative time, particularly in CRS stones, where mean operative time rose from 126.9 min in standard PCNL to 156.7 min in the flexible-nephroscopy group (p < 0.01). While their absolute times are longer than the present, may be due to differences in stone burden, case complexity mix, and operative technique. However, the study concluded that FN improves intrarenal inspection and clearance capability but predictably adds operating time. The flexible step typically prolongs the procedure because it adds systematic inspection of calyces and active retrieval/fragment management that is not always achievable with the rigid nephroscope alone. In the present study, the flexible-nephroscopy arm required fewer percutaneous accesses: most patients in the standard PCNL with FN group were managed with a single tract (56.25%) and none needed three tracts, whereas the standard PCNL group more frequently required multiple tracts, including three accesses in 17.5% of cases (p < 0.001). This is in accordance with the main rationale for adding FN or antegrade flexible ureteroscopy during PCNL in CRS. A recent prospective randomized controlled study in staghorn calculi comparing standard PNL alone versus antegrade FN-assisted PNL concluded that the flexible-assisted approach required fewer multiple percutaneous tracts, with the benefit being most evident in cases with greater stone branch complexity, which is the same clinical situation where surgeons otherwise escalate to multi-tract PCNL [ 11 ]. Likewise, Marguet et al. [ 12 ] shoed that combined flexible ureteroscopy with PCNL was specifically designed to reduce the number of access tracts required for complex renal calculi, again matching the mechanism behind your findings. In fact, the flexible instrument can reach calyces that are difficult or impossible to access with a rigid nephroscope through one tract, allowing inspection and clearance of remote calyces without creating additional accesses. In the present study, postoperative Hb concentration was significantly higher in PCNL with FN group compared with the standard PCNL group and Hb drop was significantly smaller in patients undergone PCNL with FN group (0.91 ± 0.57 g/dL) than in those who had standard PCNL (1.71 ± 0.69 g/dL). In accordance with this result is the study of Qi et al. [ 11 ] who reported that the FN-assisted group required fewer multiple tracts and showed a numerically smaller hemoglobin drop and fewer transfusions, although the difference in hemoglobin change and transfusion did not reach statistical significance in that trial (hemoglobin drop 1.73 ± 9.04 vs 0.32 ± 7.39 g/L; transfusion 3.7% vs 0%). Another study on PCNL bleeding showed that multiple tracts, larger/complex stones, and longer operative manipulation are associated with greater hemoglobin decrease/bleeding risk, which supports the interpretation that a technique helping surgeons clear stones with fewer accesses can reduce blood loss [ 13 ]. In the present study, patients who underwent PCNL with FN had lower 24-hour pain scores and less need for postoperative analgesia than those treated with standard PCNL (VAS 3.25 ± 0.76 vs 4.08 ± 0.94, p < 0.001; analgesia 34.38% vs 60%, p = 0.031). Bryniarski et al. [ 14 ] described lower analgesic requirements as an advantage of FN over PCNL. Other studies indicated that the analgesic dose used in tubeless procedures was lower than that seen in standard PCNL [ 15 , 16 ]. The lower pain and reduced analgesia in the flexible group likely reflect less access-related trauma (fewer or less extensive punctures and less rigid nephroscope torque), not a direct analgesic effect of the flexible instrument. In the present study, adding FN was associated with a shorter hospitalization (2.75 ± 1.34 vs 4.00 ± 1.83 days, p = 0.002). Different studies worldwide reported different results. Masood et al. [ 9 ] reported that the mean hospital stay was essentially the same between groups (3.07 vs 3.09 days; p = 0.849), even though FN improved SFR mainly in staghorn stones; the authors concluded that FN did not prolong hospitalization. Qi et al. [ 11 ] demonstrated that postoperative hospitalization was similar between groups (5.38 ± 1.07 vs 5.46 ± 1.43 days). On the other hand, Goktug et al. [ 10 ] reported the opposite trend: hospitalization time was significantly lower in the standard PCNL group, implying that the FN era had longer stays in their cohort. This variation between different studies could be attributed for several factors; the most important of which are postoperative imaging timing, antibiotic policies, and threshold for keeping patients after bleeding/pain Despite broad interest in FN as an adjunct to PCNL, evidence remains limited and inconsistent regarding whether adding FN translates into clinically meaningful perioperative benefits in patients with complex renal stones, particularly in routine practice settings. The present study, therefore, provide prospective comparative data from a real-world tertiary center on standard PCNL versus PCNL with FN in complex stones, focusing not only on stone clearance but also on operative metrics and patient-centered recovery outcomes. We now state clearly that our results advance current knowledge by demonstrating that FN-assisted PCNL, although associated with longer operative and fluoroscopy times and more frequent multiple tracts, was linked to a more favorable bleeding profile (smaller hemoglobin drop and lower blood loss), reduced 24-hour pain and analgesic requirement, and shorter hospital stay, without a significant difference in residual stones up to 3 months. In conclusion, adding FN to PCNL for complex renal stones improves early postoperative recovery: patients had lower blood loss, less pain at 24 hours with reduced analgesic requirement, and a shorter hospital stay compared with standard PCNL, but with longer operative and fluoroscopy times. Declarations Author Contribution All authors whose names appear on the submission made substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data; or the creation of new software used in the work;drafted the work or revised it critically for important intellectual content;approved the version to be published; and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Acknowledgement The authors highly appreciated the efforts of Dr. Qasim Al-Mayah, College of Medicine, Al-Nahrain University for data analysis. References Hasan Al-Timimi HF, Ismael AA (2024) Ismail,Comparison of Safety Outcome and Complication of SlowDescent Technique Versus Bulls Eye Technique inPercutaneous Nephrolithotomy. 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J Endourol 24:1075–1079 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 08 Mar, 2026 Editor assigned by journal 02 Mar, 2026 Submission checks completed at journal 02 Mar, 2026 First submitted to journal 27 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8988222","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":602771868,"identity":"ee5383d5-22cc-46aa-bf22-af23ff11fb36","order_by":0,"name":"hasanain Al-tamimi","email":"","orcid":"","institution":"University of Baghdad","correspondingAuthor":false,"prefix":"","firstName":"hasanain","middleName":"","lastName":"Al-tamimi","suffix":""},{"id":602771869,"identity":"366d065a-86a8-4903-9e9c-e34af04ea8ed","order_by":1,"name":"saif mohammed","email":"","orcid":"","institution":"Nahrain University","correspondingAuthor":false,"prefix":"","firstName":"saif","middleName":"","lastName":"mohammed","suffix":""},{"id":602771870,"identity":"41b51bf8-f2ba-4a73-b7f3-d27d878218b9","order_by":2,"name":"mohammed ismail","email":"data:image/png;base64,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","orcid":"","institution":"University of Baghdad","correspondingAuthor":true,"prefix":"","firstName":"mohammed","middleName":"","lastName":"ismail","suffix":""}],"badges":[],"createdAt":"2026-02-27 12:53:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8988222/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8988222/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104780824,"identity":"20eb4965-1b0b-4467-9fc4-f9c50b9856a3","added_by":"auto","created_at":"2026-03-17 07:54:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":757264,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8988222/v1/9ef25de6-88e3-49ad-92a4-d0f8b49bb544.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparison of Standard percutaneous nephrolithotomy with and without Flexible Nephroscopy in Complex Renal Stones","fulltext":[{"header":"Introduction","content":"\u003cp\u003eComplex renal stones (CRS) are a challenging type in the classification of renal stones, characterized by high stone burden, distribution in various calices, urinary tract infection (UTI) and renal dysfunction [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Surgery remains the cornerstone treatment for CRS. The traditional surgical method is percutaneous nephrolithotomy (PCNL) [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePCNL has several advantages including small trauma, high removal rate of lithotripsy and low incidence of postoperative complications [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Current recommendation steadily consider PCNL as the primary choice for treatment of renal stone exceeding 2 cm as well as for complex conformations such as staghorn calculi, where the stone size and complex anatomy often restrict the efficiency of retrograde approaches [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite the high effectiveness of PCNL, CRS remains challenging as the complete clearance is frequently restricted by calyceal anatomy, access angle, and the occurrence of wreckages in calyces away from the percutaneous tract [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Residual fragments are important form clinical point of view regardless of their size, because they can act as a focus for regrowth, persistent symptoms, and microbial infection. Furthermore, there usually a need for additional procedures or reintervention [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. These issues have augmented the interest in techniques that may improve intrarenal view at the end of PCNL to distinguish and eliminate missed fragments.\u003c/p\u003e \u003cp\u003eFlexible nephroscopy (FN) achieved through the percutaneous tract after standard PCNL has been suggested as a practical technique to visualize and remove stone fragments situated in less accessible calyces with no need to create additional tracts [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Clinical comparative investigations have testified that adding routine FN to PCNL can increase stone-free rates (SFR) and reduce the necessity for reinterventions, especially in patients with large or CRS, although potential disadvantages include longer operative time and more equipment requirements [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. However, remains unclear whether adding FN to standard PCNL provides a meaningful reduction for ancillary procedures without increasing operative time, bleeding, postoperative pain, or hospital stay. Therefore, the present study was conducted to compare the perioperative and stone-clearance outcomes of standard PCNL performed with versus PCNL with FN in patients with complex renal stones\u003c/p\u003e"},{"header":"Patients and Methods","content":"\u003cp\u003eThis study is a prospective comparative single-center study encompassing 72 consecutive patients diagnosed with CRS and scheduled for PCNL at Ghazi Al-Hariri Hospital for Surgical Specialities from January to December 2025. Eligible patients were those having any pelvic calculus and/or inferior CRS. On the other hand, pediatric patients, morbid obese, those with a history of shockwave lithotripsy (SWL), coagulopathies, or congenital anomalies of the urinary tract were excluded from the study. Following a full history-taking and clinical evaluation, all patients underwent renal ultrasound, X-ray imaging of the kidneys, ureters, and bladder (KUB), non-contrast computed tomography (NCCT) of the KUB, alongside a series of blood investigations including complete blood count, renal function tests, serum electrolytes, and coagulation profile, in addition to urine microscopy. The study received approval from the Iraqi Boad for Medical Specializations ( date, and a written informed consent was obtained from each participant.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy groups and data collection\u003c/h2\u003e \u003cp\u003ePatients were divided into two groups according to surgical management: 40 patients managed by standard PCNL alone, and 32 patients were managed by PCNL with FN. Demographic characteristics including age, sex, affected site, and stone size were collected form all patients before operation.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurgical Technique\u003c/h3\u003e\n\u003cp\u003eAll procedures were performed under general anesthesia. Patients were initially placed in the lithotomy position for cystoscopy. A 5\u0026ndash;6 Fr open-ended ureteral catheter was entered into the renal pelvis under fluoroscopic guidance, while a Foley catheter was inserted for bladder drainage.\u003c/p\u003e \u003cp\u003ePercutaneous renal access was obtained under fluoroscopic guidance using an 18-gauge access needle, aiming for a posterior calyx to achieve a straight tract to the stone-bearing calyx while minimizing vascular injury. A 0.035-inch guidewire was inserted into the collecting system, preferably coiled within the renal pelvis. Tract dilation was performed using a balloon dilator up to the desired size, followed by placement of an Amplatz sheath. Nephroscopy was performed using a rigid nephroscope. Stone fragmentation was achieved with ultrasonic lithotripsy, and fragments were evacuated using graspers and suction through the sheath. In cases of stones distributed in multiple calyces or with unfavorable angles, additional percutaneous tracts were created as required to optimize access and clearance.\u003c/p\u003e \u003cp\u003eIn the standard PCNL group, stone clearance was assessed using rigid nephroscopy and fluoroscopy. At the end of the procedure, the collecting system was inspected through the rigid nephroscope and fluoroscopy was used to evaluate for residual fragments.\u003c/p\u003e \u003cp\u003eIn the PCNL with FN group, after completion of rigid nephroscopy and fragment extraction, a flexible nephroscope was introduced through the Amplatz sheath to systematically inspect the renal pelvis and all accessible calyces. Residual fragments identified by flexible inspection were extracted using a nitinol basket and/or relocated to an accessible calyx for fragmentation and removal. Final assessment of stone clearance was performed with combined endoscopic visualization and fluoroscopy in both groups.\u003c/p\u003e \u003cp\u003eAt the end of the procedure, a nephrostomy tube and/or ureteral stent was placed based on intraoperative findings. Nephrostomy and ureteral catheters were removed once urine output was clear.\u003c/p\u003e \u003cp\u003eOperative time, fluoroscopy time, stone size, number of access, residual stone, blood loss (in mL) and blood transfusion were recorded during the operation. Visual analogue scale (VAS) was used to evaluate pain at 6 hrs and 24 hrs postoperatively. Need for analgesia during 6hr and 24hr post- surgery was also calculated. Patients were followed up for 3 months after operation during which the hospital stay and residual stone at 1 week and 3 months post-surgery were evaluated. Residual stone was defined as the presence of any detectable fragment within the collecting system on postoperative imaging using NCCT or a combination of KUB and ultrasound depending on stone radiopacity and local availability.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eThe Statistical Package for Social Science (SPSS) version 25 was used to analyze these data. Quantitative data were expressed as mean and standard deviation with independent t-test was used for group comparison. Qualitative data were expressed and number and percentage and the Chi-square test (χ2-value) was used for comparison. A p-value of less than 0.05 was considered significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eDemographic characteristics of the patients\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe mean age of the patients in standard PCNL was 45.58\u0026plusmn;7.59 years compared with 47.53\u0026plusmn;7.0 years in PCNL with FN group with no significant difference. Similarly, the two groups were comparable in sex distribution, affected side and stone size with no significant differences (Table 1)\u003c/p\u003e\n\u003cp\u003eTable 1: Demographic characteristics of the patients\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"567\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 207px;\"\u003e\n \u003cp\u003eVariables\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 168px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStandard PCNL\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n= 40)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePCNL with FN\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=32)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\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 valign=\"top\" style=\"width: 207px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge, years\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Mean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 168px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e45.58\u0026plusmn;7.59\u003c/p\u003e\n \u003cp\u003e35-62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e47.53\u0026plusmn;7.0\u003c/p\u003e\n \u003cp\u003e35-60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.264\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 207px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSex\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eMale\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Female\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 168px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e26(65%)\u003c/p\u003e\n \u003cp\u003e14(35%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e21(65.63%)\u003c/p\u003e\n \u003cp\u003e11(34.37%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.956\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 207px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAffected side\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eRight\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Left\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 168px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e23(57.5%)\u003c/p\u003e\n \u003cp\u003e17(42.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e20(%62.5)\u003c/p\u003e\n \u003cp\u003e12(37.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.667\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 207px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStone size, mm\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Mean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 168px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e4.53\u0026plusmn;2.07\u003c/p\u003e\n \u003cp\u003e2-9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e4.64\u0026plusmn;2.06\u003c/p\u003e\n \u003cp\u003e2-8.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.823\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eSD: standard deviation, PCNL: percutaneous nephrolithotomy, FN: flexible nephroscopy\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInteroperative characteristics\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMost intraoperative characteristics varied significantly between the two groups. The mean operative and fluoroscopy times \u0026nbsp;in PCNL group was 93.23\u0026plusmn;14.16 min and 6.19\u0026plusmn;0.34 min, respectively \u0026nbsp;which were shorter than that in PCNL with FN group (112.0-22.55 min and \u0026nbsp;7.98\u0026plusmn;1.59 min, respectively with significant differences (p\u0026lt;0.001 for both). Furthermore, most patients (56.25%) in the standard PCNL with FN group were treated with a single tract, and none required three tracts, whereas patients in \u0026nbsp; standard PCNL \u0026nbsp;group more frequently required multiple tracts, including three accesses in 17.5% of cases, with a significant difference (p\u0026lt;0.001). Finally, estimated blood loss was significantly lower in the PCLN with FN group (248.16\u0026plusmn;42.25mL) compared with the standard PCNL group (274.1\u0026plusmn;37.09 mL) (p=0.007) as shown in table 2.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 2: Intraoperative characteristics of the patients\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"618\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStandard PCNL\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n= 40)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePCNL with FN\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=32)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\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 valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOperative time, min\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eMean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e93.23\u0026plusmn;14.16\u003c/p\u003e\n \u003cp\u003e70-140\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e112.0-22.55\u003c/p\u003e\n \u003cp\u003e70-160\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFluoroscopy time, min\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eMean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e6.19\u0026plusmn;0.34\u003c/p\u003e\n \u003cp\u003e5.7-7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e7.98\u0026plusmn;1.59\u003c/p\u003e\n \u003cp\u003e5.4-12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNumber of access\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17(42.5%)\u003c/p\u003e\n \u003cp\u003e16(40%)\u003c/p\u003e\n \u003cp\u003e7(17.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e18(56.25%)\u003c/p\u003e\n \u003cp\u003e14(43.75%)\u003c/p\u003e\n \u003cp\u003e0(0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e0.042\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBlood loss, ml\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eMean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e274.1\u0026plusmn;37.09\u003c/p\u003e\n \u003cp\u003e200-350\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e248.16\u0026plusmn;42.25\u003c/p\u003e\n \u003cp\u003e185-335\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e0.007\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eSD: standard deviation, PCNL: percutaneous nephrolithotomy, FN: flexible nephroscopy\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePerioperative hemoglobin concentration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePreoperatively, standard PCNL and PCNL with FN displayed almost similar concentration of Hb concentration with no significant difference. However, postoperative Hb concentration was significantly higher in PCNL with FN group (12.13\u0026plusmn;1.51 g/dL) compared with the standard PCNL group (11.54\u0026plusmn;0.96 g/dL) (p=0.047). Accordingly, the calculated Hb drop was significantly smaller in patients undergone PCNL with FN group \u0026nbsp; (0.91\u0026plusmn;0.57 g/dL) than in those who had standard PCNL (1.71\u0026plusmn;0.69 g/dL) (p\u0026lt;0.001) as shown in table 3\u003c/p\u003e\n\u003cp\u003eTable 3: Perioperative hemoglobin and intraoperative blood loss\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"618\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStandard PCNL\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n= 40)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePCNL with FN\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=32)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\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 valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePreoperative \u0026nbsp;Hb, g/dl\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eMean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e13.25\u0026plusmn;1.34\u003c/p\u003e\n \u003cp\u003e10.4-15.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e13.04\u0026plusmn;1.42\u003c/p\u003e\n \u003cp\u003e10.3-15.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.518\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePostoperative Hb, g/dl\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eMean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e11.54\u0026plusmn;0.96\u003c/p\u003e\n \u003cp\u003e9.2-13.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e12.13\u0026plusmn;1.51\u003c/p\u003e\n \u003cp\u003e9.1-14.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.047\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHb difference, g/dl\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eMean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e1.71\u0026plusmn;0.69\u003c/p\u003e\n \u003cp\u003e0.8-4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 143px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.91\u0026plusmn;0.57\u003c/p\u003e\n \u003cp\u003e0.2-2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eSD: standard deviation, Hb: hemoglobin, PCNL: percutaneous nephrolithotomy, FN: flexible nephroscopy\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePostoperative findings\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEarly postoperative pain at 6 hours, assessed by VAS, was similar between groups, with no significant difference. However, by 24 hours post-surgery, pain scores were significantly lower in the PCNL with FN group (3.25\u0026plusmn;0.76) compared to standard PCNL group (4.08\u0026plusmn;0.94) (p\u0026lt;0.001). As a consequence, a greater proportion of patients in the standard PCNL group required postoperative analgesia (60%) compared with the PCNL with FN group (34.38%) (p=0.031). Furthermore, the PCNL with FN group had a significantly shorter hospital stay (2.75\u0026plusmn;1.34 days) than those in the standard PCNL group (4.0\u0026plusmn;1.83 days)(p=0.002). Regrading residual stone, it was generally comparable between the two groups whether one week or three months postoperatively with no significant differences (Table 4). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 4: Postoperative findings\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"567\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 243px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStandard PCNL\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n= 40)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePCNL with FN\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=32)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\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 valign=\"top\" style=\"width: 243px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVAS at 6h postop\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eMean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e5.5\u0026plusmn;1.32\u003c/p\u003e\n \u003cp\u003e3-8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e5.03\u0026plusmn;1.51\u003c/p\u003e\n \u003cp\u003e2-8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.165\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 243px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVAS at 24h postop\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eMean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e4.08\u0026plusmn;0.94\u003c/p\u003e\n \u003cp\u003e3-6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e3.25\u0026plusmn;0.76\u003c/p\u003e\n \u003cp\u003e2-5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 243px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eResidual stone, 1 week postop\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;No\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eYes\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e33(82.5%)\u003c/p\u003e\n \u003cp\u003e7(17.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e28(87.5%)\u003c/p\u003e\n \u003cp\u003e4(12.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.558\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 243px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eResidual stone, 3 months postop\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eNo\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eYes\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e36(90%)\u003c/p\u003e\n \u003cp\u003e4(10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e30(93.75%)\u003c/p\u003e\n \u003cp\u003e2(6.25%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.567\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 243px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNeed for analgesia\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eNo\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eYes\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e16(40%)\u003c/p\u003e\n \u003cp\u003e24(60%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e21(65.62%)\u003c/p\u003e\n \u003cp\u003e11(34.38%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e0.031\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 243px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHospital stay, days\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Mean\u0026plusmn; SD\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Range\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e4.0\u0026plusmn;1.83\u003c/p\u003e\n \u003cp\u003e2-8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e2.75\u0026plusmn;1.34\u003c/p\u003e\n \u003cp\u003e1-6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e0.002\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eSD: standard deviation\u003cstrong\u003e,\u0026nbsp;\u003c/strong\u003eVAS: visual analogue scale, PCNL: percutaneous nephrolithotomy, FN: flexible nephroscopy\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe present study aimed to compare standard PCNL versus PCNL with FN in patients with CRS regarding operative parameters, bleeding profile, postoperative pain, hospital stay, and residual stones.\u003c/p\u003e \u003cp\u003eAccording to the result of the study, adding FN to PCNL significantly increased both operative time and fluoroscopy time compared with standard PCNL. These results are consistent with many previous studies worldwide. Goktug et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] in a comparative study of standard PCNL versus PCNL combined with intraoperative antegrade FN for staghorn stones, reported longer operating time in the flexible-nephroscopy arm (about 113 min versus 95 min in standard PCNL) and also noted significantly higher fluoroscopy time with the addition of flexible nephroscopy, which aligns closely with the direction and magnitude of delay observed in the present study.\u003c/p\u003e \u003cp\u003eSimilarly, Masood et al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] reported that incorporating intraoperative FN during PCNL significantly increased operative time, particularly in CRS stones, where mean operative time rose from 126.9 min in standard PCNL to 156.7 min in the flexible-nephroscopy group (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). While their absolute times are longer than the present, may be due to differences in stone burden, case complexity mix, and operative technique. However, the study concluded that FN improves intrarenal inspection and clearance capability but predictably adds operating time. The flexible step typically prolongs the procedure because it adds systematic inspection of calyces and active retrieval/fragment management that is not always achievable with the rigid nephroscope alone.\u003c/p\u003e \u003cp\u003eIn the present study, the flexible-nephroscopy arm required fewer percutaneous accesses: most patients in the standard PCNL with FN group were managed with a single tract (56.25%) and none needed three tracts, whereas the standard PCNL group more frequently required multiple tracts, including three accesses in 17.5% of cases (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This is in accordance with the main rationale for adding FN or antegrade flexible ureteroscopy during PCNL in CRS. A recent prospective randomized controlled study in staghorn calculi comparing standard PNL alone versus antegrade FN-assisted PNL concluded that the flexible-assisted approach required fewer multiple percutaneous tracts, with the benefit being most evident in cases with greater stone branch complexity, which is the same clinical situation where surgeons otherwise escalate to multi-tract PCNL [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Likewise, Marguet et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] shoed that combined flexible ureteroscopy with PCNL was specifically designed to reduce the number of access tracts required for complex renal calculi, again matching the mechanism behind your findings.\u003c/p\u003e \u003cp\u003eIn fact, the flexible instrument can reach calyces that are difficult or impossible to access with a rigid nephroscope through one tract, allowing inspection and clearance of remote calyces without creating additional accesses.\u003c/p\u003e \u003cp\u003eIn the present study, postoperative Hb concentration was significantly higher in PCNL with FN group compared with the standard PCNL group and Hb drop was significantly smaller in patients undergone PCNL with FN group (0.91\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57 g/dL) than in those who had standard PCNL (1.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.69 g/dL). In accordance with this result is the study of Qi et al. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] who reported that the FN-assisted group required fewer multiple tracts and showed a numerically smaller hemoglobin drop and fewer transfusions, although the difference in hemoglobin change and transfusion did not reach statistical significance in that trial (hemoglobin drop 1.73\u0026thinsp;\u0026plusmn;\u0026thinsp;9.04 vs 0.32\u0026thinsp;\u0026plusmn;\u0026thinsp;7.39 g/L; transfusion 3.7% vs 0%). Another study on PCNL bleeding showed that multiple tracts, larger/complex stones, and longer operative manipulation are associated with greater hemoglobin decrease/bleeding risk, which supports the interpretation that a technique helping surgeons clear stones with fewer accesses can reduce blood loss [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn the present study, patients who underwent PCNL with FN had lower 24-hour pain scores and less need for postoperative analgesia than those treated with standard PCNL (VAS 3.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.76 vs 4.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; analgesia 34.38% vs 60%, p\u0026thinsp;=\u0026thinsp;0.031). Bryniarski et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] described lower analgesic requirements as an advantage of FN over PCNL. Other studies indicated that the analgesic dose used in tubeless procedures was lower than that seen in standard PCNL [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe lower pain and reduced analgesia in the flexible group likely reflect less access-related trauma (fewer or less extensive punctures and less rigid nephroscope torque), not a direct analgesic effect of the flexible instrument.\u003c/p\u003e \u003cp\u003eIn the present study, adding FN was associated with a shorter hospitalization (2.75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.34 vs 4.00\u0026thinsp;\u0026plusmn;\u0026thinsp;1.83 days, p\u0026thinsp;=\u0026thinsp;0.002). Different studies worldwide reported different results. Masood et al. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] reported that the mean hospital stay was essentially the same between groups (3.07 vs 3.09 days; p\u0026thinsp;=\u0026thinsp;0.849), even though FN improved SFR mainly in staghorn stones; the authors concluded that FN did not prolong hospitalization. Qi et al. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] demonstrated that postoperative hospitalization was similar between groups (5.38\u0026thinsp;\u0026plusmn;\u0026thinsp;1.07 vs 5.46\u0026thinsp;\u0026plusmn;\u0026thinsp;1.43 days). On the other hand, Goktug et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] reported the opposite trend: hospitalization time was significantly lower in the standard PCNL group, implying that the FN era had longer stays in their cohort.\u003c/p\u003e \u003cp\u003eThis variation between different studies could be attributed for several factors; the most important of which are postoperative imaging timing, antibiotic policies, and threshold for keeping patients after bleeding/pain\u003c/p\u003e \u003cp\u003eDespite broad interest in FN as an adjunct to PCNL, evidence remains limited and inconsistent regarding whether adding FN translates into clinically meaningful perioperative benefits in patients with complex renal stones, particularly in routine practice settings. The present study, therefore, provide prospective comparative data from a real-world tertiary center on standard PCNL versus PCNL with FN in complex stones, focusing not only on stone clearance but also on operative metrics and patient-centered recovery outcomes. We now state clearly that our results advance current knowledge by demonstrating that FN-assisted PCNL, although associated with longer operative and fluoroscopy times and more frequent multiple tracts, was linked to a more favorable bleeding profile (smaller hemoglobin drop and lower blood loss), reduced 24-hour pain and analgesic requirement, and shorter hospital stay, without a significant difference in residual stones up to 3 months.\u003c/p\u003e \u003cp\u003eIn conclusion, adding FN to PCNL for complex renal stones improves early postoperative recovery: patients had lower blood loss, less pain at 24 hours with reduced analgesic requirement, and a shorter hospital stay compared with standard PCNL, but with longer operative and fluoroscopy times.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors whose names appear on the submission made substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data; or the creation of new software used in the work;drafted the work or revised it critically for important intellectual content;approved the version to be published; and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors highly appreciated the efforts of Dr. Qasim Al-Mayah, College of Medicine, Al-Nahrain University for data analysis.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHasan Al-Timimi HF, Ismael AA (2024) Ismail,Comparison of Safety Outcome and Complication of SlowDescent Technique Versus Bulls Eye Technique inPercutaneous Nephrolithotomy. 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J Endourol 24:1075\u0026ndash;1079\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"urolithiasis","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ures","sideBox":"Learn more about [Urolithiasis](http://link.springer.com/journal/240)","snPcode":"240","submissionUrl":"https://submission.nature.com/new-submission/240/3","title":"Urolithiasis","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Complex renal stones, Percutaneous nephrolithotomy, Flexible nephroscopy, Residual stone","lastPublishedDoi":"10.21203/rs.3.rs-8988222/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8988222/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eComplex renal stones (CRS) continue to be challenging in percutaneous nephrolithotomy (PCNL). Flexible nephroscopy (FN) may enhance intrarenal inspection and outcomes.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo compare standard PCNL versus PCNL with FN in patients with CRS regarding operative parameters, bleeding profile, postoperative pain, hospital stay, and residual stones.\u003c/p\u003e\u003ch2\u003ePatients and Methods:\u003c/h2\u003e \u003cp\u003eThis is a prospective comparative single-center study including 72 patients with CRS treated at Ghazi Al-Hariri Hospital for Surgical Specialities. Patients were assigned into two groups according to surgical management: standard PCNL (n\u0026thinsp;=\u0026thinsp;40) and PCNL with FN (n\u0026thinsp;=\u0026thinsp;32). Operative time, fluoroscopy time, number of access tracts, blood loss, perioperative hemoglobin, pain score at 6 and 24 hours post-surgery, analgesia requirement, hospital stay, and residual stones at 1 week and 3 months were reported.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eOperative time and fluoroscopy time were significantly longer in the PCNL with FN group (112.0\u0026thinsp;\u0026plusmn;\u0026thinsp;22.55 vs 93.23\u0026thinsp;\u0026plusmn;\u0026thinsp;14.16 min; 7.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.59 vs 6.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34 min). The standard PCNL group needed more multiple tracts (three tracts: 17.5% vs 0%). Estimated blood loss was significantly lower in PCNL with FN (248.16\u0026thinsp;\u0026plusmn;\u0026thinsp;42.25 vs 274.1\u0026thinsp;\u0026plusmn;\u0026thinsp;37.09 mL). Although preoperative hemoglobin (Hb) was comparable, postoperative Hb was significantly higher in the PCNL with FN group (12.13\u0026thinsp;\u0026plusmn;\u0026thinsp;1.51 vs 11.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.96 g/dL) with a smaller Hb dropping (0.91\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57 vs 1.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.69 g/dL). Pain at 24-hour post-surgery was significantly lower in PCNL with FN (3.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.76 vs 4.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94), and there were fewer patients required analgesia (34.38% vs 60%, p\u0026thinsp;=\u0026thinsp;0.031). Furthermore, hospital stay was significantly shorter in PCNL with FN (2.75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.34 vs 4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.83 days). In contrast, residual stone was comparable between the two groups at 1 week and 3 months postoperatively with no significant differences\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eIn CRS, adding FN to PCNL was associated with longer operative and fluoroscopy times, but it reduces access tracts, 24-hour postoperative pain and analgesia requirement, improves the bleeding profile, and shortened hospital stay, without a significant difference in residual stone rates up to 3 months.\u003c/p\u003e","manuscriptTitle":"Comparison of Standard percutaneous nephrolithotomy with and without Flexible Nephroscopy in Complex Renal Stones","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-12 16:17:59","doi":"10.21203/rs.3.rs-8988222/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2026-03-09T02:12:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-02T19:22:08+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-02T19:20:00+00:00","index":"","fulltext":""},{"type":"submitted","content":"Urolithiasis","date":"2026-02-27T12:38:24+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"urolithiasis","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ures","sideBox":"Learn more about [Urolithiasis](http://link.springer.com/journal/240)","snPcode":"240","submissionUrl":"https://submission.nature.com/new-submission/240/3","title":"Urolithiasis","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"bde93082-8f3e-4b01-b974-9a7c50f1df9d","owner":[],"postedDate":"March 12th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-12T16:17:59+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-12 16:17:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8988222","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8988222","identity":"rs-8988222","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}