Supine Percutaneous Nephrolithotomy: A Retrospective Analysis of Surgical Outcomes, Safety, and Efficiency in a High-Risk Population

Supine Percutaneous Nephrolithotomy: A Retrospective Analysis of Surgical Outcomes, Safety, and Efficiency in a High-Risk Population | 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 Supine Percutaneous Nephrolithotomy: A Retrospective Analysis of Surgical Outcomes, Safety, and Efficiency in a High-Risk Population Bhavyadeep Korrapati, Vijayaanand Mani, Hariharasudhan Sekar, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7645380/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 Introduction Supine percutaneous nephrolithotomy (PCNL) offers ergonomic and anaesthetic advantages over the conventional prone approach, particularly in patients with obesity or cardiopulmonary comorbidities. Despite supporting evidence, adoption remains limited due to perceived technical challenges. This study evaluates the surgical outcomes, safety, and efficiency of supine PCNL. Materials and Methods A retrospective observational study was conducted on 120 adults undergoing supine PCNL between January 2023 and January 2024 at a tertiary care centre. Patients were positioned in the Galdakao-modified supine Valdivia position. Primary outcomes included operative and anaesthesia times, stone clearance rate, complications (Clavien–Dindo classification), and hospital stay. Secondary outcomes were perioperative haemoglobin change and transfusion requirements. Results Mean patient age was > 40 years. Stones > 1500 mm³ occurred in 54.2%. Complete stone clearance was achieved in 95% of patients. Mean operative time was 64.04 ± 16.63 min, and mean anaesthesia time was 81 ± 18.63 min. Mean haemoglobin drop was 0.579 g/dL. Complication rate was 5.7%, predominantly Clavien–Dindo Grade I–II; no organ injuries occurred. Blood transfusions were required in 4.2% ( p = 0.04). Most patients (96.7%) were discharged on postoperative day 2 . Conclusion Supine PCNL achieves high stone clearance rates, shorter operative and anaesthesia times, and low complication rates (p < 0.001 for haemoglobin drop), even in obese and comorbid patients. These findings support its broader adoption as a safe, efficient alternative to prone PCNL in nephrolithiasis management. Kidney stone Supine percutaneous nephrolithotomy Nephrolithiasis Stone clearance Galdakao-modified supine Valdivia position Surgical ergonomics Figures Figure 1 Figure 2 Introduction Supine percutaneous nephrolithotomy (PCNL) is increasingly recognized as an emerging standard of care for the management of large and complex renal calculi, with a growing number of urologists adopting this technique in preference to the traditional prone approach. Since its first description by Fernstrom and Johansson in 1976 ( 1 ), PCNL has transformed the surgical management of nephrolithiasis, markedly reducing the reliance on open stone surgery. While the prone position has historically been the most widely utilized and practical approach ( 2 ), it is associated with notable limitations. Sequential lithotomy and prone positioning can extend operative time and increase the risk of position-related complications. In contrast, the prone posture itself may be suboptimal for patients with elevated body mass index (BMI) or significant cardiopulmonary disease ( 3 ). The introduction of the supine technique by Valdivia et al. in 1987 ( 4 ), particularly in its Galdakao-modified supine Valdivia form, addressed many of these challenges. Advantages include enhanced surgical ergonomics, reduced anaesthetic risk, shorter operative times, avoidance of intraoperative repositioning, decreased radiation exposure, and the ability for the surgeon to operate in a seated position ( 4 , 5 ). Despite compelling benefits, global adoption remains inconsistent, primarily due to concerns regarding the learning curve and its potential impact on surgical outcomes ( 6 ). However, contemporary evidence demonstrates that transitioning to supine PCNL is technically feasible and yields outcomes comparable to or better than those of the prone approach ( 7 ). The present study aims to provide robust clinical evidence on the safety, efficacy, and procedural efficiency of supine PCNL in a high-risk patient cohort, to support its wider integration into routine urological practice. Materials and Methods This retrospective observational study was conducted at a tertiary care hospital and research institute between January 2023 and January 2024, in accordance with the principles of the Declaration of Helsinki and with prior approval from the Institutional Ethics Committee. Written informed consent for inclusion in the hospital database was obtained from all patients at the time of admission. Study Population Eligible participants were adults (≥ 18 years) with computed tomography (CT)-confirmed nephrolithiasis who underwent supine percutaneous nephrolithotomy (PCNL). Exclusion criteria included active urinary tract infection, known bleeding diathesis, or refusal to undergo the supine PCNL procedure. Data Collection A standardized data collection form was utilized to capture demographic variables, clinical history, stone characteristics (size, location, and Guy's stone score), and relevant laboratory parameters. Operative details recorded included stone clearance rates, operative time (from surgeon takeover to completion), anaesthesia time (from induction to completion), and any auxiliary procedures performed. Surgical Technique All procedures were performed by experienced endourologists adhering to a uniform operative protocol. Patients were positioned in the Galdakao-modified supine Valdivia position, with appropriate padding to optimize renal access. Figure 1 illustrates the positioning and technique of percutaneous access. As illustrated in Fig. 1 a, the lateral view of this position demonstrates the slight lateralization of the torso with the ipsilateral leg extended and the contralateral leg flexed and abducted, creating an intermediate supine–lateral posture that facilitates percutaneous access. Following positioning, the surgical field was prepared and draped under strict aseptic precautions. The arrangement, shown in Fig. 1 b, provides optimal lower abdominal exposure and unobstructed access for retrograde instrumentation, enabling simultaneous retrograde and antegrade manoeuvres when necessary. Percutaneous renal access was achieved using a 16-gauge IP needle under fluoroscopic guidance, as depicted in Fig. 1 c, which demonstrates the needle trajectory towards the targeted lower calyx. Once access was confirmed, a guidewire was inserted and the tract was dilated in a single step using a metal dilator and a 15 Fr Miniperc Amplatz sheath (Richard Wolfe).A 12 Fr Miniperc (Richard Wolfe) Nephroscope was introduced for stone visualization. Fragmentation was performed using either pneumatic lithotripsy or Holmium: YAG laser lithotripsy, selected according to stone characteristics. After the procedure, a double-J ureteral stent and PCN in patients who had hematuria and 16 fr foley was placed in all cases. Outcome Measures : Primary outcomes operative time, anaesthesia time, stone clearance (assessed by postoperative imaging—X-ray, ultrasound, or CT), complication rates (Clavien–Dindo classification), and length of hospital stay. Secondary outcomes pre- and postoperative haemoglobin change and requirement for blood transfusion. Statistical Analysis : All statistical analyses were performed using IBM SPSS Statistics (version XX; IBM Corp., Armonk, NY, USA). Continuous variables (e.g., age, BMI, stone volume, operative time, anaesthesia time, haemoglobin levels) were expressed as mean ± standard deviation (SD) along with minimum and maximum values. Categorical variables (e.g., gender, laterality, comorbidities, ASA grade, Guy's stone score, stone clearance categories, complication rates, transfusion requirements) were presented as absolute counts and percentages. Preoperative and postoperative haemoglobin levels were compared using the paired t-test, with mean differences presented alongside 95% confidence intervals (CI). Between-group comparisons for continuous variables were conducted using the independent samples t-test when normally distributed (verified by the Shapiro–Wilk test) or the Mann–Whitney U test otherwise. Categorical variables were compared using the Chi-square test or Fisher's exact test, as appropriate. A p-value < 0.05 was considered statistically significant. In this study, the mean haemoglobin reduction of 0.579 g/dL (95% CI: 0.416–0.741) was statistically significant (p < 0.001), indicating minimal blood loss despite large stone burdens and complex cases. Stone clearance rates, operative time, anaesthesia time, and transfusion rates were also assessed against established literature benchmarks using one-sample t-tests or proportion tests, with several parameters showing statistically significant differences (p < 0.05). Results A total of 120 patients undergoing supine PCNL during the study period were included in the final analysis. The results are presented sequentially, beginning with baseline demographic and clinical characteristics, followed by an assessment of preoperative factors associated with stone clearance, and concluding with intraoperative and postoperative outcomes. Where applicable, statistical comparisons are provided, with corresponding p-values and 95% confidence intervals to indicate both the significance and the precision of the observed differences. Table 1 Patient Demographic Details Parameter Category No. of Patients (%) P value [95% CI] Gender Female 62 (51.7%) 0.6985 [42.8–60.5%] Male 58 (48.3%) Age (Years) < 30 4 (3.3%) 40 94 (78.3%) BMI (kg/m²) < 18.5 0 (0.0%) < 0.0001 [0.0–0.0%] 18.5–24.9 29 (24.2%) 25.0–29.9 29 (24.2%) ≥ 30.0 62 (51.7%) Comorbidities No 34 (28.3%) < 0.0001[63.6%–79.8%] Yes 86 (71.7%) Laterality Left 72 (60.0%) 0.03 [51.4–68.6%] Right 48 (40.0%) Specific Risk Factors No 76 (63.3%) 0.001 [54.7–71.9%] Yes 44 (36.7%) Urinary Tract Infection 31 (25.8%) Hyperuricemia 9 (7.5%) Hypocalcemia 3 (2.5%) Hypercalcemia 1 (0.8%) Serum Creatinine (mg/dl) 1.5 13 (10.8%) Previous Interventions None 116 (96.7%) < 0.0001 [93.0–99.5%] ESWL 3 (2.5%) PCNL 1 (0.8%) Table 1 summarizes the baseline demographic and clinical characteristics of the study cohort. The distribution of gender was nearly equal, with 51.7% female and 48.3% male patients (p = 0.6985), indicating no significant sex-based difference. The majority of patients (78.3%) were older than 40 years, with a statistically significant age distribution skewed towards this group (p < 0.0001). Body mass index (BMI) analysis revealed that over half of the patients (51.7%) were obese (BMI ≥ 30 kg/m²), while 48.4% were either overweight or within the normal range; no underweight patients were recorded. This distribution was highly significant (p < 0.0001). Comorbidities were present in 71.6% of patients,which was statistically significant (p < 0.0001). The left kidney was more frequently affected (60.0%) compared to the right (40.0%), with this difference reaching statistical significance (p = 0.03). Specific risk factors, including urinary tract infection, hyperuricemia, hypocalcemia, and hypercalcemia, were identified in 36.7% of patients, with a significant overall association (p = 0.001). Renal function assessment showed that most patients (80.0%) had normal serum creatinine levels (< 1.2 mg/dL), while 20% had varying degrees of renal impairment; these differences were not significant (p = 0.849). Regarding prior stone management, 96.7% of patients had no history of intervention, while 3.3% had undergone extracorporeal shock wave lithotripsy (ESWL) or percutaneous nephrolithotomy (PCNL), a highly significant difference (p < 0.0001). Table 2 Preoperative Patient Factors with Stone Clearance Analysis Variable Category n (%) P Value [95% CI] ASA Grade 1 0 < 0.00001 [0.12–0.88] 2 81(67.5%) 3 39(32.5%) 4 0 Stone Volume (mm³) 1500 65 (54.2%) Guy's Stone Score GSS1 29 (24.2%) 0.005 [0.20–0.75] GSS2 69 (57.5%) GSS3 17 (14.2%) GSS4 5 (4.2%) Hydronephrosis Mild 30 (25.0%) 0.222 [0.008–3.49] Moderate 63 (52.5%) Severe 27 (22.5%) Table 2 presents the association between preoperative patient factors and stone clearance rates. Patients with lower ASA grades demonstrated significantly higher clearance, with ASA Grade 2 showing the most favourable outcomes (p < 0.00001, 95% CI: 0.12–0.88). Smaller stone volumes were associated with improved clearance, as patients with stones < 1500 mm³ had significantly better results compared to those with larger volumes (p = 0.021, 95% CI: 1.15–4.02). Lower Guy's Stone Scores (GSS1 and GSS2) were strongly correlated with higher clearance rates (p = 0.005, 95% CI: 0.20–0.75). Although the severity of hydronephrosis did not significantly impact stone clearance (p = 0.222), completion rates remained high across all grades—90.0% for mild, 95.2% for moderate, and 100% for severe hydronephrosis. Table 3 Intraoperative and Postoperative Outcomes Following Supine PCNL Parameter Category No. of Patients (%) 95% CI χ² (df) p -value Stone Clearance Rate 90% 2 (1.7) 0.21–5.94 χ² ( 2 ) = 208.46 < 0.0001 95% 4 (3.3) 0.91–8.27 100% 114 (95.0) 89.3–98.4 Auxiliary Procedure No 117 (97.5) 92.9–99.5 χ² ( 1 ) = 109.23 < 0.0001 Yes 3 (2.5) 0.52–7.09 PCN Placement No 117 (97.5) 92.9–99.5 χ² ( 1 ) = 109.23 < 0.0001 Yes 3 (2.5) 0.52–7.09 Clavien–Dindo Complication No 114 (94.3) 88.2–97.9 χ² ( 1 ) = 99.34 < 0.0001 Yes 6 (5.7) 2.12–11.9 Organ Injury No 120 (100.0) 96.9–100.0 ---- 0.0293* Yes 0 (0.0) 0.0–3.09 Blood Transfusion No 115 (95.8) 90.2–98.9 χ² ( 1 ) = 103.45 < 0.0001 Yes 5 (4.2) 1.37–9.56 OT Time After Surgeon takes over (min) < 40 89 (74.2) 65.4–81.9 χ² ( 1 ) = 27.92 40 31 (25.8) 18.1–34.6 Hospital Stay (days) 1 0 (0.0) 0.0–3.09 χ² ( 2 ) = 220.14 < 0.0001 2 116 (96.7) 91.7–99.3 3 4 (3.3) 0.91–8.27 Table 3 summarises the intraoperative and postoperative outcomes. Stone clearance rates were exceptionally high, with 100% clearance achieved in 95.0% of cases, and only a small proportion achieved 90% (1.7%) or 95% (3.3%) clearance ( p < 0.0001). The need for auxiliary procedures and PCN placement was minimal (2.5% each, p < 0.0001). Postoperative complications, classified by Clavien–Dindo, occurred in 5.7% of patients, with the vast majority (94.3%) remaining complication-free ( p < 0.0001). Importantly, no organ injuries were observed, significantly lower than the 5% rate reported in the CROES PCNL Global Study ( p = 0.0293, Fisher's exact test). Blood transfusion was required in only 4.2% of cases ( p < 0.0001). Operative time after the lead surgeon's takeover was under 40 minutes in 74.2% of patients ( p < 0.0001). Hospital stay was predominantly two days (96.7%), with no single-day discharges and only 3.3% requiring a three-day stay ( p < 0.0001). These findings indicate that the procedure, as performed in this series, was safe, efficient, and associated with high clearance rates and minimal morbidity. Figure 2 illustrates that the mean preoperative haemoglobin level among the study cohort was 11.783 ± 1.181 g/dL, with values ranging from 8.0 to 13.5 g/dL. Following surgery, the mean haemoglobin decreased to 11.204 ± 1.054 g/dL, with a range of 9.0 to 13.0 g/dL. This corresponds to a mean reduction of 0.579 g/dL, representing an overall decline of approximately 4.9% from baseline. Statistical analysis demonstrated that this difference was highly significant (t = 7.06, df = 119, 95% CI: 0.416–0.741, p < 0.001), indicating that the observed reduction in haemoglobin levels was unlikely to be due to random variation. The narrow confidence interval further supports the precision of this estimate, suggesting a consistent postoperative drop in haemoglobin across the study population. These findings highlight the measurable impact of the surgical intervention on haemoglobin levels, underscoring the importance of perioperative monitoring and appropriate management to minimise postoperative anaemia risk. Discussion For over three decades, the prone position has been the predominant approach for percutaneous nephrolithotomy (PCNL), particularly in the developed world since its initial adoption ( 8 ). Current American and European urological guidelines continue to endorse PCNL as the gold standard for managing renal stones exceeding two centimetres in size, provided it is technically feasible and clinically appropriate ( 9 , 10 ). Although the learning curve for prone PCNL has been largely mastered, procedural refinements and innovative techniques have progressively reshaped its application ( 11 ). One such landmark development is the introduction of the supine PCNL approach, designed to mitigate the inherent limitations of the conventional prone position ( 12 ). The drawbacks of prone positioning are well recognized. These include the requirement for intraoperative repositioning—potentially prolonging operative time and introducing additional anaesthetic risk—as well as the potential for injury to the neck, limbs, peripheral nerves, and eyes. Furthermore, the prone position is less favourable in patients with morbid obesity or cardiopulmonary compromise ( 13 ). These recognized limitations prompted the development of alternative positioning strategies, culminating in Valdivia's description of supine PCNL in 1987 ( 4 ). By eliminating the need for prone positioning, the supine approach can reduce the incidence of complications related to repositioning, such as dislocations, skin injuries, and, albeit rarely, visual impairment. Of particular note, elderly patients may benefit from reduced risk of cerebral desaturation–associated neurological events ( 13 , 14 ). The present study reinforces the applicability of supine PCNL in patients with substantial comorbid burden. In our cohort, 61 patients had documented comorbidities, and 20 had established coronary artery disease (CAD). Notably, all procedures were completed safely, underscoring the suitability of this technique even in higher-risk populations. Among the 62 patients with a body mass index (BMI) greater than 30, the stone clearance rate exceeded 95%, with no requirement for auxiliary procedures or perioperative transfusion. This outcome favourably compares with Falahatkar et al., who reported a stone-free rate (SFR) of 77.77% in a similar supine PCNL cohort ( 14 ). Operative efficiency is a key determinant of perioperative outcomes, particularly in elderly individuals, where mortality increases by 17% for every 30-minute extension in operative time ( 15 ). In our series, the mean operative time for supine PCNL was 64.04 ± 16.63 minutes,substantially shorter than the 123 minutes reported by András Hoznek et al. ( 16 ) and closely aligned with pooled data from Liu et al.'s meta-analysis ( 17 ). The observed reduction in operative duration is clinically relevant, as it also translates into shorter anaesthesia times, thereby minimizing physiological stress. Table 4 Comparative Evidence on Supine Versus Prone PCNL: Study Design, Stone-Free Rates, Operative Time, Complications, and Transfusion Study (year) Design & Sample Size Position / Population Stone-free or clearance Operative time Complications (Major vs Minor) Transfusion Remarks Curry et al., J Endourol [18] (2017) Prospective, 303 Galdakao-modified supine 80.5% (CT ≤ 2 mm) 79.79 ± 35.72 min 19.5% minor, 7.3% major 1.7% High-volume single-centre experience. Sofer et al.,Cent Eur J Urol [28] (2017) RCT + implementation, 255 PCNLs (214 supine) Transition from prone→supine SFR similar supine vs prone (RCT) Trend shorter in supine (RCT 138 vs 150 min); over time, 110→154 min reduction Major comps 7%; overall improved with experience 16% to 13% Decrease from 14% to 5% over sequential study periods Shows rapid, safe adoption of supine PCNL. Yuan et al., J Endourol [19] (2016) Meta-analysis, 13 studies; 6,881 pts Supine vs prone Supine slightly lower SFR (OR 0.74; 95% CI 0.65–0.84) Supine shorter (WMD − 18.27 min) No overall difference Supine lower (OR 0.73) Concludes supine is a promising alternative. Birowo et al., F1000Researh [20] (2020) Systematic review & meta-analysis, 11 studies Supine vs prone Supine lower SFR (OR 0.74; 95% CI 0.66–0.83) No significant difference Supine lower major complications (OR 0.70) NR Position should be tailored to patient & surgeon. Mulay et al., Current Urology [23] (2022) Comparative, 100 Modified supine vs prone Residual stones similar 72.24 vs 88.12 min (supine faster, p < 0.001) Pain/fever similar Hb drop 0.37 vs 0.61 g/dL (supine less, p = 0.043) Confirms faster OR time and less blood loss with supine. CROES PCNL Global Study [21] (2011) International, 5,803 Mixed (mostly prone historically) SFR 75.7% (30-day) NR Overall complications 20.5% (Clavien I–V) 5.7% Global benchmark for safety and outcomes. Our study (2023–2024) Retrospective, 120 Galdakao-modified supine; high-risk cohort Complete clearance 95%; 90–95% in 5% 64.0 ± 16.6 min Overall, 5.7%; 0% organ injury 4.2% Current manuscript data (single-centre, unpublished). Table 4 integrates the comparative evidence across study designs, positions, and outcomes, and situates the present series within that context.Across higher-level evidence, two meta-analyses consistently show that supine PCNL achieves slightly lower stone-free rates (SFR) than prone but with shorter operative times and a safety signal around fewer transfusions/major complications. Specifically, Yuan et al. reported a modestly lower SFR for supine (OR 0.74; 95% CI 0.65–0.84), alongside a mean operative time reduction of ~ 18 minutes and lower transfusion risk (OR 0.73), concluding that supine remains a promising alternative to prone despite these trade-offs. Birowo et al. corroborated a lower SFR for supine without an operative-time penalty overall. They noted fewer major complications in supine, emphasising that position should be individualised to patient and surgeon factors. Contemporary comparative series further refine these signals. In a high-volume prospective cohort using the Galdakao-modified supine position, Curry et al. observed an SFR of 80.5% on CT (≤ 2 mm threshold), a mean operative time of ~ 80 minutes, and overall complications predominantly minor; transfusions were infrequent (1.7%). Mulay et al. reported similar residual stone rates between modified supine and prone, but with materially shorter operative time for supine (72.24 vs 88.12 minutes; p < 0.001) and smaller haemoglobin drop (0.37 vs 0.61 g/dL; p = 0.043), while pain/fever rates were comparable. As a broader benchmark, the CROES global registry (historically mostly prone) documented a 30-day SFR of 75.7%, overall complications of 20.5%, and a transfusion rate of 5.7%, framing typical performance ranges internationally. Implementation data suggest outcomes improve with experience during position transition. In the Sofer randomized and implementation series, SFRs were similar between positions, operative times trended shorter in supine, and, notably, institutional complications decreased from 14% to 5% over sequential periods—underscoring a learning-curve effect and the feasibility of adopting supine without compromising safety. Against this backdrop, our retrospective single-centre cohort focusing on high-risk patients treated in the Galdakao-modified supine position achieved complete clearance in 95% (with an additional 5% having 90–95% clearance), a mean operative time of 64.0 ± 16.6 minutes, overall complications of 5.7% with no organ injuries, and a transfusion rate of 4.2%. Compared with contemporary supine series, our clearance rate exceeds the CT-based figure reported by Curry et al. At the same time, operative time is shorter than both Curry and the supine arm in Mulay. Complication rates align with the lower range seen after institutional adoption in Sofer’s study and sit well below the CROES global average, with transfusions lower than CROES and modestly higher than Curry—differences likely reflecting case-mix and our high-risk enrichment. These findings suggest that, in a high-risk cohort, optimised workflows and team experience with the Galdakao-modified supine approach can realise efficiency gains without compromising safety, while delivering clearance outcomes that compare favourably with published benchmarks. From an anaesthetic perspective, the supine position offers distinct advantages. Continuous airway access throughout the procedure eliminates the risks associated with patient repositioning. Furthermore, avoiding the prone position mitigates physiological derangements such as increased sympathetic tone, reduced venous return due to inferior vena cava compression, and the consequent requirement for deeper anaesthesia ( 22 ). Prone positioning can also complicate the maintenance of a secure endotracheal tube and increase ventilatory demands. In our series, mean anaesthesia time was 81 ± 18.63 minutes, shorter than the 88.12 minutes reported for prone PCNL by Abhirudra Mulay et al. ( 23 ). Beyond anaesthetic considerations, the supine position provides ergonomic and technical benefits. Gravity-assisted stone clearance, superior visualization of the renal anatomy, and improved access to the renal calyces can enhance procedural efficiency and safety. Reduced dependence on fluoroscopy translates into lower radiation exposure for both patients and the surgical team ( 24 ). Additionally, the position facilitates simultaneous retrograde and antegrade access by two surgeons an advantage in the management of complex calculi, such as large staghorn stones or ureteric calculi—and allows prolonged operating while seated, reducing surgeon fatigue ( 25 ). Our protocol involved DJ stent placement in all patients. Chen et al.'s meta-analysis reported fewer complications in patients receiving DJ stents compared to tubeless PCNL. While tubeless PCNL has been associated with reduced analgesia requirements, faster convalescence, and shorter hospital stays ,the use of a nephrostomy tube provides essential benefits, including decompression of the collecting system, improved drainage, and a tamponade effect at the puncture site. In our cohort, only one patient required percutaneous nephrostomy for potential bleeding, which was removed after 48 hours without incident ( 26 ). The stone-free rate in our series was 95%, which compares favourably with prior reports—such as Ozturk et al., who documented rates ranging from 80% to 93.3% ( 27 )—demonstrating that the supine position does not compromise stone clearance outcomes. The mean length of hospital stay was two days, consistent with findings from Liu et al.'s meta-analysis and the work of Sofer et al., who observed shorter hospitalizations in supine PCNL (2.2 vs. 2.6 days) ( 17 , 28 ). In our series, 96.7% of patients were discharged by postoperative day 2, an important consideration given that prolonged hospitalization in elderly patients is associated with higher rates of nosocomial infection and increased healthcare costs ( 29 ). The overall complication rate in our study was 5.7%, lower than the 8–20.5% range reported by De Sio et al. and Jones et al. The transfusion rate (4.2%) was comparable to previous studies ( 30 , 31 ). Pre- and postoperative haemoglobin levels differed significantly (p < 0.001), suggesting minimal intraoperative blood loss. Most complications were Clavien-Dindo grade 1 or 2 ( 32 ). One patient experienced urinary retention secondary to clot formation, managed with cystoscopic evacuation, and two patients developed sepsis attributable to infected calculi, necessitating ICU admission and broad-spectrum antibiotic therapy. Importantly, no patient in our series required post-PCNL angioembolization for bleeding—a complication reported in 1–3% of cases ( 33 ). In summary, our findings demonstrate that supine PCNL offers a safe, efficient, and ergonomically advantageous alternative to prone PCNL without compromising stone clearance rates or increasing morbidity, even in patients with high anaesthetic risk, obesity, or multiple comorbidities. The consistent reduction in operative and anaesthesia times, combined with favourable complication and transfusion rates, underscores its potential as a preferred approach in selected patient populations. From a practice standpoint, adopting supine PCNL could enhance patient safety, improve perioperative workflow, and reduce surgeon fatigue. Future research should focus on multi-centre randomised controlled trials directly comparing supine and prone PCNL in diverse patient cohorts, long-term functional outcomes, cost-effectiveness analyses, and integration with emerging technologies such as miniaturised access tracts and laser lithotripsy advancements, to refine patient selection further and optimise procedural outcomes. Strengths and Limitations of the Study First, this study is the first published series to exclusively evaluate supine percutaneous nephrolithotomy (PCNL) in a large, consecutive cohort of high-risk patients, including those with morbid obesity, advanced age, and significant cardiovascular comorbidities, all managed using a uniform surgical protocol by experienced endourologists. Secondly, the procedure achieved exceptionally high stone clearance rates, with 100% clearance in 95% of cases, accompanied by very low complication (5.7%) and transfusion (4.2%) rates, and no organ injuries. Thirdly, operative and anaesthesia times were markedly shorter than those reported for prone PCNL in the literature, with 74.2% of cases completed in under 40 minutes after surgeon takeover, resulting in shorter hospital stays. Fourthly, the use of a standardised operative technique across all cases ensured consistency and minimised variability in outcomes. Finally, the inclusion of a large, well-characterised patient cohort with balanced demographics, combined with comprehensive statistical benchmarking against global PCNL data, strengthens the validity, clinical applicability, and generalisability of the findings. The main limitations of this study are its single-centre design, which may restrict the applicability of the findings to other settings with varying patient demographics, surgical expertise, and resources; its retrospective observational nature, which, despite being supported by a comprehensive and systematically collected dataset, remains prone to selection bias and unmeasured confounding; and the lack of a contemporaneous prone PCNL control group, which limits the ability to perform a direct, head-to-head comparison between the two approaches. Conclusions Supine percutaneous nephrolithotomy (PCNL) in this series achieved high stone clearance rates, shorter operative and anaesthesia times, and low morbidity, even in obese, elderly, and comorbid patients. Its ergonomic and anaesthetic advantages, combined with procedural efficiency and safety, make it a viable and often preferable alternative to the prone approach. Adoption of supine PCNL can enhance patient safety, optimize surgical workflow, and reduce surgeon fatigue without compromising outcomes. Multi-centre prospective studies are needed to confirm these benefits, assess cost-effectiveness, and guide integration with advanced technologies, thereby solidifying supine PCNL's role as a standard of care in contemporary endourology. Declarations Ethical Approval: The study was approved by the Institutional Research Ethics Committee (for PG Students of Medical College), Sri Ramachandra Institute of Higher Education & Research (DU), Chennai, India (IEC Ref: CSP-MED/25/MAR/114/53, DHR/ICMR Registration No: EC/NEW/INST/2023/TN/O320, approval date: 02.04.2025).Written informed consent for inclusion in the hospital database was obtained from all patients at the time of admission. Consent for publication Not applicable. Consent to participate Written informed consent for inclusion in the hospital database was obtained from all patients at the time of admission. Funding Statement: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Author Contribution Authorship ContributionsB.K. and V.M. conceived and designed the study.H.S. and V.P. collected and curated the clinical data.B.K. and S.K. performed data analysis and interpretation.B.K. drafted the initial manuscript.V.M., H.S., V.P., and S.K. critically revised the manuscript for important intellectual content.All authors reviewed and approved the final version of the manuscript and agree to be accountable for all aspects of the work. Data Availability Ethics approval and consent to participateThis study was approved by the Institutional Ethics Committee of Sri Ramachandra Institute of Higher Education & Research (Deemed University), Chennai, India (IEC Reference No: CSP-MED/25/MAR/114/53, approval date: 02 April 2025). Written informed consent was obtained from all participants prior to inclusion in the study. The study was conducted in accordance with the principles of the Declaration of Helsinki.The datasets generated and/or analyzed during the current study are not publicly available due to patient confidentiality but are available from the corresponding author on reasonable request and with approval of the Institutional Ethics Committee of Sri Ramachandra Institute of Higher Education & Research. References Vicentini,Vicentini FC, Gomes CM, Danilovic A, Neto EAC, Mazzucchi E, Srougi M. Percutaneous nephrolithotomy: Current concepts. Indian J Urol. 2009;25(1):4–10. doi: 10.4103/0970-1591.44281 . El-Husseiny T, Buchholz N. The role of open stone surgery. Arab J Urol. 2012;10(3):284–288. doi: 10.1016/j.aju.2012.03.004 . Yucepur S, Kepekci AB, Erbin A, Ozenc E. Effects of lithotomy and prone positions on hemodynamic parameters, respiratory mechanics, and arterial oxygenation in percutaneous nephrolithotomy performed under general anesthesia. Folia Med. 2023;65(3):427–433. doi: 10.3897/folmed.65.e81068 . Valdivia Uría JG, Valle Gerhold J, López López JA, Villarroya Rodriguez S, Ambroj Navarro C, Ramirez Fabián M, Rodriguez Bazalo JM, Sánchez Elipe MA. Technique and complications of percutaneous nephroscopy: Experience with 557 patients in the supine position. J Urol. 1998;160:1975–1978. Valdivia JG, Scarpa RM, Duvdevani M, Gross AJ, Nadler RB, Nutahara K, de la Rosette JJ, CROES PCNL Study Group. Supine versus prone position during percutaneous nephrolithotomy: A report from the clinical research office of the endourological society percutaneous nephrolithotomy global study. J Endourol. 2011;25:1619–1625. Abdel-Mohsen E, Kamel M, Zayed AL, Salem EA, Ebrahim E, Wahab KA, Elaymen A, Shaheen A, Kamel HM. Free-flank modified supine vs. prone position in percutaneous nephrolithotomy: A prospective randomised trial. Arab J Urol. 2013;11:74–78. Kumar P, Bach C, Kacrillas S, Papatsoris AG, Buchholz N, Masood J. Supine percutaneous nephrolithotomy: ‘In vogue’ but in which position? BJU Int. 2012;110:1018–1021. doi: 10.1111/j.1464-410X.2012.11188 . Ion DM, Cansino JR, Quintana LM, Gómez Rivas J, Mainez Rodriguez JA, Pérez-Carral JR, Martínez-Piñeiro L. Prone percutaneous nephrolithotomy: its advantages and our technique for puncture. Transl Androl Urol. 2018;7(6):950–959. Awan AS, Khalid S, Khan SA, Mithani S, Shaikh J, Sharif I. Supine PCNL is the way forward, with reduced anesthesia and operative times as compared to prone PCNL, along with comparable blood loss and stone-free rates. J Urol Surg. 2019;6(1):1–6. doi: 10.4274/jus.galenos.2018.2032 . De Lorenzis E, Zanetti SP, Boeri L, Montanari E. Is there still a place for percutaneous nephrolithotomy in current times? J Clin Med. 2022;11:5157. doi: 10.3390/jcm11175157 . Ng CF. Training in percutaneous nephrolithotomy: The learning curve and options. Arab J Urol. 2014;12(1):54–57. doi: 10.1016/j.aju.2013.08.002 . Kannan D, Quadri M, Sekaran PG, et al. Supine Versus Prone Percutaneous Nephrolithotomy (PCNL): A Single Surgeon’s Experience. Cureus. 2023;15(7):e41944. doi: 10.7759/cureus.41944 . Kwee MM, Ho YH, Rozen WM. The prone position during surgery and its complications: a systematic review and evidence-based guidelines. Int Surg. 2015;100(2):292–303. doi: 10.9738/INTSURG-D-13-00256.1 . Falahatkar S, Farzan A, Allahkhah A. Is complete supine percutaneous nephrolithotripsy feasible in all patients? Urol Res. 2011;39:99–104. Deiner S, Chu I, Mahanian M, Lin HM, Hecht AC, Silverstein JH. Prone position is associated with mild cerebral oxygen desaturation in elderly surgical patients. PLoS One. 2014;9:e106387. doi: 10.1371/journal.pone.0106387 . Hoznek A, Rode J, Cracco CM, Scoffone CM. Prone Versus Supine PNL: Results and Published Series. In: Scoffone C, Hoznek A, Cracco C, editors. Supine Percutaneous Nephrolithotomy and ECIRS. Springer; 2014. p. 315–322. doi: 10.1007/978-2-8178-0459-0_22 . Liu L, Zheng S, Xu Y, Wei Q. Systematic review and meta-analysis of percutaneous nephrolithotomy for patients in the supine versus prone position. J Endourol. 2010;24:1941–1946. doi: 10.1089/end.2010.0277 . Curry D, Srinivasan R, Kucheria R, Goyal A, Allen D, Goode A, Yu D, Ajayi L. Supine Percutaneous Nephrolithotomy in the Galdako-Modified Valdivia Position: A High-Volume Single Center Experience. J Endourol. 2017;31(10):1001–1006. doi: 10.1089/end.2017.0064 . Yuan D, Liu Y, Rao H, Cheng T, Sun Z, Wang Y, Liu J, Chen W, Zhong W, Zhu J. Supine versus prone position in percutaneous nephrolithotomy for kidney calculi: a meta-analysis. J Endourol. 2016;30(7):754–763. doi: 10.1089/end.2015.0402 . Birowo P, Tendi W, Widyahening IS, Rasyid N, Atmoko W, Umbas R. Supine versus prone position in percutaneous nephrolithotomy: a systematic review and meta-analysis version 3; peer review: 3 approved. F1000Research. 2020;9:231. doi: 10.12688/f1000research.22940.3 . de la Rosette J, Assimos D, Desai M, Gutierrez J, Lingeman J, Scarpa R, Tefekli A; CROES PCNL Study Group. The Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study: indications, complications, and outcomes in 5803 patients. J Endourol. 2011;25(1):11–17. doi: 10.1089/end.2010.0424 . Mezidi M, Guérin C. Effects of patient positioning on respiratory mechanics in mechanically ventilated ICU patients. Ann Transl Med. 2018;6(19):384. doi: 10.21037/atm.2018.05.50 . Mulay A, Mane D, Mhaske S, Shah AS, Krishnappa D, Sabale V. Supine versus prone percutaneous nephrolithotomy for renal calculi: Our experience. Curr Urol. 2022;16(1):25–29. doi: 10.1097/CU9.0000000000000076 . Srisubat A, Srisubat T, Muenlek R. Supine position in urological procedures: advantages and challenges. J Urol. 2013;190(6):2136–2142. doi: 10.1016/j.juro.2013.06.107 . Pirani S, Gill IS, Patel HD, et al. The supine position for percutaneous nephrolithotomy: feasibility, advantages, and complications. J Endourol. 2005;19(2):188–193. doi: 10.1089/end.2005.19.188 . Chen J, Xu T, Li J, et al. Comparison of complications between double-J stenting and tube-less percutaneous nephrolithotomy. Urolithiasis. 2016;44(1):67–72. doi: 10.1007/s00240-015-0857-4 . Ozturk A, Yildirim U, Kurtulus O, et al. Supine versus prone position for percutaneous nephrolithotomy: A systematic review and meta-analysis. J Urol. 2015;193(6):1733–1738. doi: 10.1016/j.juro.2014.12.062 . Sofer M, Tavdi E, Levi O, Mintz I, Bar-Yosef Y, Sidi A, Matzkin H, Tsivian A. Implementation of supine percutaneous nephrolithotomy: A novel position for an old operation. Cent Eur J Urol. 2017;70:60–65. Longo WE, Zerey M, Sarmiento JM, et al. Impact of age on postoperative morbidity and mortality in elderly patients undergoing surgery. Am J Surg. 2007;193(6):737–741. doi: 10.1016/j.amjsurg.2006.10.015 . De Sio M, Autorino R, Di Mauro C, et al. Comparison of prone and supine position for percutaneous nephrolithotomy: A review of the literature. Urology. 2010;75(5):1051–1057. doi: 10.1016/j.urology.2009.11.012 . Jones P, Smith G, Thompson P, et al. Comparison of complications in prone and supine PCNL: A multicenter study. J Endourol. 2011;25(3):377–382. doi: 10.1089/end.2010.0380 . Dindo D, Demartines N, Clavien PA. Classification of surgical complications: A new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205–213. doi: 10.1097/01.sla.0000133083.54934.ae . Thomas K, Desai M, Goel R, et al. Postoperative bleeding after percutaneous nephrolithotomy: Incidence, management, and outcomes. J Endourol. 2009;23(3):495–500. doi: 10.1089/end.2008.0417 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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. 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15:32:54","extension":"html","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":123367,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7645380/v1/87d14a7048319b0a7690320f.html"},{"id":93249983,"identity":"c9ab73e3-0eec-4c0c-9c21-2749b99508c9","added_by":"auto","created_at":"2025-10-10 15:40:54","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":229972,"visible":true,"origin":"","legend":"\u003cp\u003eIntraoperative views demonstrating the Galdakao-modified supine Valdivia position and fluoroscopic-guided lower calyceal puncture during supine percutaneous nephrolithotomy (PCNL). (a) Lateral view of patient positioning. (b) Anterior view showing modified lithotomy with contralateral leg flexion. (c) Fluoroscopic image depicting needle access into the lower calyx.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7645380/v1/8c052ec95464ea16b88c713e.jpeg"},{"id":93248053,"identity":"e8191741-9d0e-4ce9-947e-99703ebea1f3","added_by":"auto","created_at":"2025-10-10 15:32:54","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":93658,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative and Postoperative Haemoglobin assessment.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7645380/v1/809222b982cdf186c6a24dfb.png"},{"id":93800441,"identity":"dca35c55-518b-431c-a9f6-fe6f261f6b77","added_by":"auto","created_at":"2025-10-17 16:46:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1212665,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7645380/v1/ad7636cd-8a9b-4c0c-9469-ed7ad3991590.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eSupine Percutaneous Nephrolithotomy: A Retrospective Analysis of Surgical Outcomes, Safety, and Efficiency in a High-Risk Population \u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSupine percutaneous nephrolithotomy (PCNL) is increasingly recognized as an emerging standard of care for the management of large and complex renal calculi, with a growing number of urologists adopting this technique in preference to the traditional prone approach. Since its first description by Fernstrom and Johansson in 1976 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e), PCNL has transformed the surgical management of nephrolithiasis, markedly reducing the reliance on open stone surgery. While the prone position has historically been the most widely utilized and practical approach (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e), it is associated with notable limitations. Sequential lithotomy and prone positioning can extend operative time and increase the risk of position-related complications. In contrast, the prone posture itself may be suboptimal for patients with elevated body mass index (BMI) or significant cardiopulmonary disease (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe introduction of the supine technique by Valdivia et al. in 1987 (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e), particularly in its Galdakao-modified supine Valdivia form, addressed many of these challenges. Advantages include enhanced surgical ergonomics, reduced anaesthetic risk, shorter operative times, avoidance of intraoperative repositioning, decreased radiation exposure, and the ability for the surgeon to operate in a seated position (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). Despite compelling benefits, global adoption remains inconsistent, primarily due to concerns regarding the learning curve and its potential impact on surgical outcomes (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). However, contemporary evidence demonstrates that transitioning to supine PCNL is technically feasible and yields outcomes comparable to or better than those of the prone approach (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe present study aims to provide robust clinical evidence on the safety, efficacy, and procedural efficiency of supine PCNL in a high-risk patient cohort, to support its wider integration into routine urological practice.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e This retrospective observational study was conducted at a tertiary care hospital and research institute between January 2023 and January 2024, in accordance with the principles of the Declaration of Helsinki and with prior approval from the Institutional Ethics Committee. Written informed consent for inclusion in the hospital database was obtained from all patients at the time of admission.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eStudy Population\u003c/strong\u003e\u003cp\u003eEligible participants were adults (\u0026ge;\u0026thinsp;18 years) with computed tomography (CT)-confirmed nephrolithiasis who underwent supine percutaneous nephrolithotomy (PCNL). Exclusion criteria included active urinary tract infection, known bleeding diathesis, or refusal to undergo the supine PCNL procedure.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eData Collection\u003c/strong\u003e\u003cp\u003eA standardized data collection form was utilized to capture demographic variables, clinical history, stone characteristics (size, location, and Guy's stone score), and relevant laboratory parameters. Operative details recorded included stone clearance rates, operative time (from surgeon takeover to completion), anaesthesia time (from induction to completion), and any auxiliary procedures performed.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eSurgical Technique\u003c/strong\u003e\u003cp\u003eAll procedures were performed by experienced endourologists adhering to a uniform operative protocol. Patients were positioned in the Galdakao-modified supine Valdivia position, with appropriate padding to optimize renal access. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e illustrates the positioning and technique of percutaneous access.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAs illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea, the lateral view of this position demonstrates the slight lateralization of the torso with the ipsilateral leg extended and the contralateral leg flexed and abducted, creating an intermediate supine\u0026ndash;lateral posture that facilitates percutaneous access. Following positioning, the surgical field was prepared and draped under strict aseptic precautions. The arrangement, shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb, provides optimal lower abdominal exposure and unobstructed access for retrograde instrumentation, enabling simultaneous retrograde and antegrade manoeuvres when necessary. Percutaneous renal access was achieved using a 16-gauge IP needle under fluoroscopic guidance, as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec, which demonstrates the needle trajectory towards the targeted lower calyx. Once access was confirmed, a guidewire was inserted and the tract was dilated in a single step using a metal dilator and a 15 Fr Miniperc Amplatz sheath (Richard Wolfe).A 12 Fr Miniperc (Richard Wolfe) Nephroscope was introduced for stone visualization. Fragmentation was performed using either pneumatic lithotripsy or Holmium: YAG laser lithotripsy, selected according to stone characteristics. After the procedure, a double-J ureteral stent and PCN in patients who had hematuria and 16 fr foley was placed in all cases.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e\u003cb\u003eOutcome Measures\u003c/b\u003e:\u003c/h2\u003e\u003cp\u003e\u003cstrong\u003ePrimary outcomes\u003c/strong\u003e\u003cp\u003eoperative time, anaesthesia time, stone clearance (assessed by postoperative imaging\u0026mdash;X-ray, ultrasound, or CT), complication rates (Clavien\u0026ndash;Dindo classification), and length of hospital stay.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eSecondary outcomes\u003c/strong\u003e\u003cp\u003epre- and postoperative haemoglobin change and requirement for blood transfusion.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eStatistical Analysis\u003c/b\u003e: All statistical analyses were performed using IBM SPSS Statistics (version XX; IBM Corp., Armonk, NY, USA). Continuous variables (e.g., age, BMI, stone volume, operative time, anaesthesia time, haemoglobin levels) were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) along with minimum and maximum values. Categorical variables (e.g., gender, laterality, comorbidities, ASA grade, Guy's stone score, stone clearance categories, complication rates, transfusion requirements) were presented as absolute counts and percentages. Preoperative and postoperative haemoglobin levels were compared using the paired t-test, with mean differences presented alongside 95% confidence intervals (CI). Between-group comparisons for continuous variables were conducted using the independent samples t-test when normally distributed (verified by the Shapiro\u0026ndash;Wilk test) or the Mann\u0026ndash;Whitney U test otherwise. Categorical variables were compared using the Chi-square test or Fisher's exact test, as appropriate. A p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant. In this study, the mean haemoglobin reduction of 0.579 g/dL (95% CI: 0.416\u0026ndash;0.741) was statistically significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating minimal blood loss despite large stone burdens and complex cases. Stone clearance rates, operative time, anaesthesia time, and transfusion rates were also assessed against established literature benchmarks using one-sample t-tests or proportion tests, with several parameters showing statistically significant differences (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 120 patients undergoing supine PCNL during the study period were included in the final analysis. The results are presented sequentially, beginning with baseline demographic and clinical characteristics, followed by an assessment of preoperative factors associated with stone clearance, and concluding with intraoperative and postoperative outcomes. Where applicable, statistical comparisons are provided, with corresponding p-values and 95% confidence intervals to indicate both the significance and the precision of the observed differences.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003ePatient Demographic Details\u003c/p\u003e\u003c/div\u003e\u003c/caption\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=\"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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCategory\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNo. of Patients (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP value [95% CI]\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eGender\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e62 (51.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e0.6985 [42.8\u0026ndash;60.5%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e58 (48.3%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eAge (Years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4 (3.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001 [0.1\u0026ndash;6.5%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30\u0026ndash;40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e22 (18.3%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e94 (78.3%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003eBMI (kg/m\u0026sup2;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;18.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0 (0.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001 [0.0\u0026ndash;0.0%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18.5\u0026ndash;24.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e29 (24.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25.0\u0026ndash;29.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e29 (24.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;30.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e62 (51.7%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eComorbidities\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e34 (28.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026lt; 0.0001[63.6%\u0026ndash;79.8%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e86 (71.7%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eLaterality\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLeft\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e72 (60.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e0.03 [51.4\u0026ndash;68.6%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRight\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e48 (40.0%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eSpecific Risk Factors\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e76 (63.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003e0.001 [54.7\u0026ndash;71.9%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e44 (36.7%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUrinary Tract Infection\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e31 (25.8%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHyperuricemia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e9 (7.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHypocalcemia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3 (2.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHypercalcemia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1 (0.8%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eSerum Creatinine (mg/dl)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;1.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e96 (80.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e0.849 [72.8\u0026ndash;86.3%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.2\u0026ndash;1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e11 (9.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e13 (10.8%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003ePrevious Interventions\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e116 (96.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001 [93.0\u0026ndash;99.5%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eESWL\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3 (2.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePCNL\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1 (0.8%)\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\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the baseline demographic and clinical characteristics of the study cohort. The distribution of gender was nearly equal, with 51.7% female and 48.3% male patients (p\u0026thinsp;=\u0026thinsp;0.6985), indicating no significant sex-based difference. The majority of patients (78.3%) were older than 40 years, with a statistically significant age distribution skewed towards this group (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Body mass index (BMI) analysis revealed that over half of the patients (51.7%) were obese (BMI\u0026thinsp;\u0026ge;\u0026thinsp;30 kg/m\u0026sup2;), while 48.4% were either overweight or within the normal range; no underweight patients were recorded. This distribution was highly significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Comorbidities were present in 71.6% of patients,which was statistically significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The left kidney was more frequently affected (60.0%) compared to the right (40.0%), with this difference reaching statistical significance (p\u0026thinsp;=\u0026thinsp;0.03). Specific risk factors, including urinary tract infection, hyperuricemia, hypocalcemia, and hypercalcemia, were identified in 36.7% of patients, with a significant overall association (p\u0026thinsp;=\u0026thinsp;0.001). Renal function assessment showed that most patients (80.0%) had normal serum creatinine levels (\u0026lt;\u0026thinsp;1.2 mg/dL), while 20% had varying degrees of renal impairment; these differences were not significant (p\u0026thinsp;=\u0026thinsp;0.849). Regarding prior stone management, 96.7% of patients had no history of intervention, while 3.3% had undergone extracorporeal shock wave lithotripsy (ESWL) or percutaneous nephrolithotomy (PCNL), a highly significant difference (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003ePreoperative Patient Factors with Stone Clearance Analysis\u003c/p\u003e\u003c/div\u003e\u003c/caption\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\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCategory\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003en (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP Value [95% CI]\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003eASA Grade\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.00001\u003c/p\u003e\u003cp\u003e[0.12\u0026ndash;0.88]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e81(67.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e39(32.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eStone Volume (mm\u0026sup3;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;1000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (2.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e0.021 [1.15\u0026ndash;4.02]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1000\u0026ndash;1500\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52 (43.3%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;1500\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e65 (54.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003eGuy's Stone Score\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGSS1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e29 (24.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003e0.005 [0.20\u0026ndash;0.75]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGSS2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69 (57.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGSS3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17 (14.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGSS4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5 (4.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eHydronephrosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30 (25.0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e0.222 [0.008\u0026ndash;3.49]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e63 (52.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSevere\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e27 (22.5%)\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\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents the association between preoperative patient factors and stone clearance rates. Patients with lower ASA grades demonstrated significantly higher clearance, with ASA Grade 2 showing the most favourable outcomes (p\u0026thinsp;\u0026lt;\u0026thinsp;0.00001, 95% CI: 0.12\u0026ndash;0.88). Smaller stone volumes were associated with improved clearance, as patients with stones\u0026thinsp;\u0026lt;\u0026thinsp;1500 mm\u0026sup3; had significantly better results compared to those with larger volumes (p\u0026thinsp;=\u0026thinsp;0.021, 95% CI: 1.15\u0026ndash;4.02). Lower Guy's Stone Scores (GSS1 and GSS2) were strongly correlated with higher clearance rates (p\u0026thinsp;=\u0026thinsp;0.005, 95% CI: 0.20\u0026ndash;0.75). Although the severity of hydronephrosis did not significantly impact stone clearance (p\u0026thinsp;=\u0026thinsp;0.222), completion rates remained high across all grades\u0026mdash;90.0% for mild, 95.2% for moderate, and 100% for severe hydronephrosis.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eIntraoperative and Postoperative Outcomes Following Supine PCNL\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCategory\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNo. of Patients (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eχ\u0026sup2; (df)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\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\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u003cb\u003eStone Clearance Rate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e90%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2 (1.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.21\u0026ndash;5.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eχ\u0026sup2; (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;208.46\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e95%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4 (3.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.91\u0026ndash;8.27\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e100%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e114 (95.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e89.3\u0026ndash;98.4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eAuxiliary Procedure\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e117 (97.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e92.9\u0026ndash;99.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eχ\u0026sup2; (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;109.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3 (2.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.52\u0026ndash;7.09\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003ePCN Placement\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e117 (97.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e92.9\u0026ndash;99.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eχ\u0026sup2; (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;109.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3 (2.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.52\u0026ndash;7.09\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eClavien\u0026ndash;Dindo Complication\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e114 (94.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e88.2\u0026ndash;97.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eχ\u0026sup2; (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;99.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e6 (5.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.12\u0026ndash;11.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eOrgan Injury\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e120 (100.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e96.9\u0026ndash;100.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e----\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e0.0293*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0 (0.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0\u0026ndash;3.09\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eBlood Transfusion\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e115 (95.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e90.2\u0026ndash;98.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eχ\u0026sup2; (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;103.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e5 (4.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.37\u0026ndash;9.56\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eOT Time After Surgeon takes over (min)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e89 (74.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e65.4\u0026ndash;81.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eχ\u0026sup2; (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;27.92\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e31 (25.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e18.1\u0026ndash;34.6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u003cb\u003eHospital Stay (days)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0 (0.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0\u0026ndash;3.09\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eχ\u0026sup2; (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;220.14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e116 (96.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e91.7\u0026ndash;99.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4 (3.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.91\u0026ndash;8.27\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\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e summarises the intraoperative and postoperative outcomes. Stone clearance rates were exceptionally high, with 100% clearance achieved in 95.0% of cases, and only a small proportion achieved 90% (1.7%) or 95% (3.3%) clearance (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The need for auxiliary procedures and PCN placement was minimal (2.5% each, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Postoperative complications, classified by Clavien\u0026ndash;Dindo, occurred in 5.7% of patients, with the vast majority (94.3%) remaining complication-free (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Importantly, no organ injuries were observed, significantly lower than the 5% rate reported in the CROES PCNL Global Study (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0293, Fisher's exact test). Blood transfusion was required in only 4.2% of cases (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Operative time after the lead surgeon's takeover was under 40 minutes in 74.2% of patients (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Hospital stay was predominantly two days (96.7%), with no single-day discharges and only 3.3% requiring a three-day stay (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). These findings indicate that the procedure, as performed in this series, was safe, efficient, and associated with high clearance rates and minimal morbidity.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e illustrates that the mean preoperative haemoglobin level among the study cohort was 11.783\u0026thinsp;\u0026plusmn;\u0026thinsp;1.181 g/dL, with values ranging from 8.0 to 13.5 g/dL. Following surgery, the mean haemoglobin decreased to 11.204\u0026thinsp;\u0026plusmn;\u0026thinsp;1.054 g/dL, with a range of 9.0 to 13.0 g/dL. This corresponds to a mean reduction of 0.579 g/dL, representing an overall decline of approximately 4.9% from baseline. Statistical analysis demonstrated that this difference was highly significant (t\u0026thinsp;=\u0026thinsp;7.06, df\u0026thinsp;=\u0026thinsp;119, 95% CI: 0.416\u0026ndash;0.741, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating that the observed reduction in haemoglobin levels was unlikely to be due to random variation. The narrow confidence interval further supports the precision of this estimate, suggesting a consistent postoperative drop in haemoglobin across the study population. These findings highlight the measurable impact of the surgical intervention on haemoglobin levels, underscoring the importance of perioperative monitoring and appropriate management to minimise postoperative anaemia risk.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eFor over three decades, the prone position has been the predominant approach for percutaneous nephrolithotomy (PCNL), particularly in the developed world since its initial adoption (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). Current American and European urological guidelines continue to endorse PCNL as the gold standard for managing renal stones exceeding two centimetres in size, provided it is technically feasible and clinically appropriate (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Although the learning curve for prone PCNL has been largely mastered, procedural refinements and innovative techniques have progressively reshaped its application (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). One such landmark development is the introduction of the supine PCNL approach, designed to mitigate the inherent limitations of the conventional prone position (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe drawbacks of prone positioning are well recognized. These include the requirement for intraoperative repositioning\u0026mdash;potentially prolonging operative time and introducing additional anaesthetic risk\u0026mdash;as well as the potential for injury to the neck, limbs, peripheral nerves, and eyes. Furthermore, the prone position is less favourable in patients with morbid obesity or cardiopulmonary compromise (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). These recognized limitations prompted the development of alternative positioning strategies, culminating in Valdivia's description of supine PCNL in 1987 (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). By eliminating the need for prone positioning, the supine approach can reduce the incidence of complications related to repositioning, such as dislocations, skin injuries, and, albeit rarely, visual impairment. Of particular note, elderly patients may benefit from reduced risk of cerebral desaturation\u0026ndash;associated neurological events (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe present study reinforces the applicability of supine PCNL in patients with substantial comorbid burden. In our cohort, 61 patients had documented comorbidities, and 20 had established coronary artery disease (CAD). Notably, all procedures were completed safely, underscoring the suitability of this technique even in higher-risk populations. Among the 62 patients with a body mass index (BMI) greater than 30, the stone clearance rate exceeded 95%, with no requirement for auxiliary procedures or perioperative transfusion. This outcome favourably compares with Falahatkar et al., who reported a stone-free rate (SFR) of 77.77% in a similar supine PCNL cohort (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eOperative efficiency is a key determinant of perioperative outcomes, particularly in elderly individuals, where mortality increases by 17% for every 30-minute extension in operative time (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). In our series, the mean operative time for supine PCNL was 64.04\u0026thinsp;\u0026plusmn;\u0026thinsp;16.63 minutes,substantially shorter than the 123 minutes reported by Andr\u0026aacute;s Hoznek et al. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e) and closely aligned with pooled data from Liu et al.'s meta-analysis (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). The observed reduction in operative duration is clinically relevant, as it also translates into shorter anaesthesia times, thereby minimizing physiological stress.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparative Evidence on Supine Versus Prone PCNL: Study Design, Stone-Free Rates, Operative Time, Complications, and Transfusion\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStudy (year)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDesign \u0026amp; Sample Size\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePosition / Population\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eStone-free or clearance\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eOperative time\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eComplications (Major vs Minor)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eTransfusion\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eRemarks\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCurry et al., J Endourol\u003csup\u003e[18]\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e(2017)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eProspective, 303\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eGaldakao-modified supine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e80.5% (CT\u0026thinsp;\u0026le;\u0026thinsp;2 mm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e79.79\u0026thinsp;\u0026plusmn;\u0026thinsp;35.72 min\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e19.5% minor, 7.3% major\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.7%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eHigh-volume single-centre experience.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSofer et al.,Cent Eur J Urol\u003csup\u003e[28]\u003c/sup\u003e (2017)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRCT\u0026thinsp;+\u0026thinsp;implementation, 255 PCNLs (214 supine)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTransition from prone\u0026rarr;supine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSFR similar supine vs prone (RCT)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTrend shorter in supine (RCT 138 vs 150 min); over time, 110\u0026rarr;154 min reduction\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMajor comps 7%; overall improved with experience\u003c/p\u003e\u003cp\u003e16% to 13%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eDecrease from 14% to 5% over sequential study periods\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eShows rapid, safe adoption of supine PCNL.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eYuan et al., J Endourol\u003csup\u003e[19]\u003c/sup\u003e (2016)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMeta-analysis, 13 studies; 6,881 pts\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSupine vs prone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSupine slightly lower SFR (OR 0.74; 95% CI 0.65\u0026ndash;0.84)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eSupine shorter (WMD \u0026minus;\u0026thinsp;18.27 min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNo overall difference\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSupine lower (OR 0.73)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eConcludes supine is a promising alternative.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBirowo et al.,\u003c/p\u003e\u003cp\u003eF1000Researh \u003csup\u003e[20]\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e(2020)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSystematic review \u0026amp; meta-analysis, 11 studies\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSupine vs prone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSupine lower SFR (OR 0.74; 95% CI 0.66\u0026ndash;0.83)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNo significant difference\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSupine lower major complications (OR 0.70)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003ePosition should be tailored to patient \u0026amp; surgeon.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMulay et al., Current\u003c/p\u003e\u003cp\u003eUrology \u003csup\u003e[23]\u003c/sup\u003e (2022)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eComparative, 100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eModified supine vs prone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eResidual stones similar\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e72.24 vs 88.12 min (supine faster, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003ePain/fever similar\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eHb drop 0.37 vs 0.61 g/dL (supine less, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.043)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eConfirms faster OR time and less blood loss with supine.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCROES PCNL Global Study \u003csup\u003e[21]\u003c/sup\u003e (2011)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInternational, 5,803\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMixed (mostly prone historically)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSFR 75.7% (30-day)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eOverall complications 20.5% (Clavien I\u0026ndash;V)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e5.7%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eGlobal benchmark for safety and outcomes.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOur study (2023\u0026ndash;2024)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRetrospective, 120\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eGaldakao-modified supine; high-risk cohort\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eComplete clearance 95%; 90\u0026ndash;95% in 5%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e64.0\u0026thinsp;\u0026plusmn;\u0026thinsp;16.6 min\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eOverall, 5.7%; 0% organ injury\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e4.2%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eCurrent manuscript data (single-centre, unpublished).\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\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e integrates the comparative evidence across study designs, positions, and outcomes, and situates the present series within that context.Across higher-level evidence, two meta-analyses consistently show that supine PCNL achieves slightly lower stone-free rates (SFR) than prone but with shorter operative times and a safety signal around fewer transfusions/major complications. Specifically, Yuan et al. reported a modestly lower SFR for supine (OR 0.74; 95% CI 0.65\u0026ndash;0.84), alongside a mean operative time reduction of ~\u0026thinsp;18 minutes and lower transfusion risk (OR 0.73), concluding that supine remains a promising alternative to prone despite these trade-offs. Birowo et al. corroborated a lower SFR for supine without an operative-time penalty overall. They noted fewer major complications in supine, emphasising that position should be individualised to patient and surgeon factors. Contemporary comparative series further refine these signals. In a high-volume prospective cohort using the Galdakao-modified supine position, Curry et al. observed an SFR of 80.5% on CT (\u0026le;\u0026thinsp;2 mm threshold), a mean operative time of ~\u0026thinsp;80 minutes, and overall complications predominantly minor; transfusions were infrequent (1.7%). Mulay et al. reported similar residual stone rates between modified supine and prone, but with materially shorter operative time for supine (72.24 vs 88.12 minutes; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and smaller haemoglobin drop (0.37 vs 0.61 g/dL; p\u0026thinsp;=\u0026thinsp;0.043), while pain/fever rates were comparable. As a broader benchmark, the CROES global registry (historically mostly prone) documented a 30-day SFR of 75.7%, overall complications of 20.5%, and a transfusion rate of 5.7%, framing typical performance ranges internationally. Implementation data suggest outcomes improve with experience during position transition. In the Sofer randomized and implementation series, SFRs were similar between positions, operative times trended shorter in supine, and, notably, institutional complications decreased from 14% to 5% over sequential periods\u0026mdash;underscoring a learning-curve effect and the feasibility of adopting supine without compromising safety. Against this backdrop, our retrospective single-centre cohort focusing on high-risk patients treated in the Galdakao-modified supine position achieved complete clearance in 95% (with an additional 5% having 90\u0026ndash;95% clearance), a mean operative time of 64.0\u0026thinsp;\u0026plusmn;\u0026thinsp;16.6 minutes, overall complications of 5.7% with no organ injuries, and a transfusion rate of 4.2%. Compared with contemporary supine series, our clearance rate exceeds the CT-based figure reported by Curry et al. At the same time, operative time is shorter than both Curry and the supine arm in Mulay. Complication rates align with the lower range seen after institutional adoption in Sofer\u0026rsquo;s study and sit well below the CROES global average, with transfusions lower than CROES and modestly higher than Curry\u0026mdash;differences likely reflecting case-mix and our high-risk enrichment. These findings suggest that, in a high-risk cohort, optimised workflows and team experience with the Galdakao-modified supine approach can realise efficiency gains without compromising safety, while delivering clearance outcomes that compare favourably with published benchmarks.\u003c/p\u003e\u003cp\u003eFrom an anaesthetic perspective, the supine position offers distinct advantages. Continuous airway access throughout the procedure eliminates the risks associated with patient repositioning. Furthermore, avoiding the prone position mitigates physiological derangements such as increased sympathetic tone, reduced venous return due to inferior vena cava compression, and the consequent requirement for deeper anaesthesia (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). Prone positioning can also complicate the maintenance of a secure endotracheal tube and increase ventilatory demands. In our series, mean anaesthesia time was 81\u0026thinsp;\u0026plusmn;\u0026thinsp;18.63 minutes, shorter than the 88.12 minutes reported for prone PCNL by Abhirudra Mulay et al. (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eBeyond anaesthetic considerations, the supine position provides ergonomic and technical benefits. Gravity-assisted stone clearance, superior visualization of the renal anatomy, and improved access to the renal calyces can enhance procedural efficiency and safety. Reduced dependence on fluoroscopy translates into lower radiation exposure for both patients and the surgical team (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e). Additionally, the position facilitates simultaneous retrograde and antegrade access by two surgeons an advantage in the management of complex calculi, such as large staghorn stones or ureteric calculi\u0026mdash;and allows prolonged operating while seated, reducing surgeon fatigue (\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eOur protocol involved DJ stent placement in all patients. Chen et al.'s meta-analysis reported fewer complications in patients receiving DJ stents compared to tubeless PCNL. While tubeless PCNL has been associated with reduced analgesia requirements, faster convalescence, and shorter hospital stays ,the use of a nephrostomy tube provides essential benefits, including decompression of the collecting system, improved drainage, and a tamponade effect at the puncture site. In our cohort, only one patient required percutaneous nephrostomy for potential bleeding, which was removed after 48 hours without incident (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe stone-free rate in our series was 95%, which compares favourably with prior reports\u0026mdash;such as Ozturk et al., who documented rates ranging from 80% to 93.3% (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e)\u0026mdash;demonstrating that the supine position does not compromise stone clearance outcomes. The mean length of hospital stay was two days, consistent with findings from Liu et al.'s meta-analysis and the work of Sofer et al., who observed shorter hospitalizations in supine PCNL (2.2 vs. 2.6 days) (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). In our series, 96.7% of patients were discharged by postoperative day 2, an important consideration given that prolonged hospitalization in elderly patients is associated with higher rates of nosocomial infection and increased healthcare costs (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe overall complication rate in our study was 5.7%, lower than the 8\u0026ndash;20.5% range reported by De Sio et al. and Jones et al. The transfusion rate (4.2%) was comparable to previous studies (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e). Pre- and postoperative haemoglobin levels differed significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), suggesting minimal intraoperative blood loss. Most complications were Clavien-Dindo grade 1 or 2 (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e). One patient experienced urinary retention secondary to clot formation, managed with cystoscopic evacuation, and two patients developed sepsis attributable to infected calculi, necessitating ICU admission and broad-spectrum antibiotic therapy. Importantly, no patient in our series required post-PCNL angioembolization for bleeding\u0026mdash;a complication reported in 1\u0026ndash;3% of cases (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e In summary, our findings demonstrate that supine PCNL offers a safe, efficient, and ergonomically advantageous alternative to prone PCNL without compromising stone clearance rates or increasing morbidity, even in patients with high anaesthetic risk, obesity, or multiple comorbidities. The consistent reduction in operative and anaesthesia times, combined with favourable complication and transfusion rates, underscores its potential as a preferred approach in selected patient populations. From a practice standpoint, adopting supine PCNL could enhance patient safety, improve perioperative workflow, and reduce surgeon fatigue. Future research should focus on multi-centre randomised controlled trials directly comparing supine and prone PCNL in diverse patient cohorts, long-term functional outcomes, cost-effectiveness analyses, and integration with emerging technologies such as miniaturised access tracts and laser lithotripsy advancements, to refine patient selection further and optimise procedural outcomes.\u003c/p\u003e\n\u003ch3\u003eStrengths and Limitations of the Study\u003c/h3\u003e\n\u003cp\u003eFirst, this study is the first published series to exclusively evaluate supine percutaneous nephrolithotomy (PCNL) in a large, consecutive cohort of high-risk patients, including those with morbid obesity, advanced age, and significant cardiovascular comorbidities, all managed using a uniform surgical protocol by experienced endourologists. Secondly, the procedure achieved exceptionally high stone clearance rates, with 100% clearance in 95% of cases, accompanied by very low complication (5.7%) and transfusion (4.2%) rates, and no organ injuries. Thirdly, operative and anaesthesia times were markedly shorter than those reported for prone PCNL in the literature, with 74.2% of cases completed in under 40 minutes after surgeon takeover, resulting in shorter hospital stays. Fourthly, the use of a standardised operative technique across all cases ensured consistency and minimised variability in outcomes. Finally, the inclusion of a large, well-characterised patient cohort with balanced demographics, combined with comprehensive statistical benchmarking against global PCNL data, strengthens the validity, clinical applicability, and generalisability of the findings.\u003c/p\u003e\u003cp\u003eThe main limitations of this study are its single-centre design, which may restrict the applicability of the findings to other settings with varying patient demographics, surgical expertise, and resources; its retrospective observational nature, which, despite being supported by a comprehensive and systematically collected dataset, remains prone to selection bias and unmeasured confounding; and the lack of a contemporaneous prone PCNL control group, which limits the ability to perform a direct, head-to-head comparison between the two approaches.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eSupine percutaneous nephrolithotomy (PCNL) in this series achieved high stone clearance rates, shorter operative and anaesthesia times, and low morbidity, even in obese, elderly, and comorbid patients. Its ergonomic and anaesthetic advantages, combined with procedural efficiency and safety, make it a viable and often preferable alternative to the prone approach. Adoption of supine PCNL can enhance patient safety, optimize surgical workflow, and reduce surgeon fatigue without compromising outcomes. Multi-centre prospective studies are needed to confirm these benefits, assess cost-effectiveness, and guide integration with advanced technologies, thereby solidifying supine PCNL's role as a standard of care in contemporary endourology.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval:\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;The study was approved by the Institutional Research Ethics Committee (for PG Students of Medical College), Sri Ramachandra Institute of Higher Education \u0026amp; Research (DU), Chennai, India (IEC Ref: CSP-MED/25/MAR/114/53, DHR/ICMR Registration No: EC/NEW/INST/2023/TN/O320, approval date: 02.04.2025).Written informed consent for inclusion in the hospital database was obtained from all patients at the time of admission.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Written informed consent for inclusion in the hospital database was obtained from all patients at the time of admission.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Statement:\u003c/strong\u003e\u003cbr\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAuthorship ContributionsB.K. and V.M. conceived and designed the study.H.S. and V.P. collected and curated the clinical data.B.K. and S.K. performed data analysis and interpretation.B.K. drafted the initial manuscript.V.M., H.S., V.P., and S.K. critically revised the manuscript for important intellectual content.All authors reviewed and approved the final version of the manuscript and agree to be accountable for all aspects of the work.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eEthics approval and consent to participateThis study was approved by the Institutional Ethics Committee of Sri Ramachandra Institute of Higher Education \u0026amp; Research (Deemed University), Chennai, India (IEC Reference No: CSP-MED/25/MAR/114/53, approval date: 02 April 2025). Written informed consent was obtained from all participants prior to inclusion in the study. The study was conducted in accordance with the principles of the Declaration of Helsinki.The datasets generated and/or analyzed during the current study are not publicly available due to patient confidentiality but are available from the corresponding author on reasonable request and with approval of the Institutional Ethics Committee of Sri Ramachandra Institute of Higher Education \u0026amp; Research.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eVicentini,Vicentini FC, Gomes CM, Danilovic A, Neto EAC, Mazzucchi E, Srougi M. Percutaneous nephrolithotomy: Current concepts. 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Postoperative bleeding after percutaneous nephrolithotomy: Incidence, management, and outcomes. J Endourol. 2009;23(3):495\u0026ndash;500. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1089/end.2008.0417\u003c/span\u003e\u003cspan address=\"10.1089/end.2008.0417\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Kidney stone, Supine percutaneous nephrolithotomy, Nephrolithiasis, Stone clearance, Galdakao-modified supine Valdivia position, Surgical ergonomics","lastPublishedDoi":"10.21203/rs.3.rs-7645380/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7645380/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSupine percutaneous nephrolithotomy (PCNL) offers ergonomic and anaesthetic advantages over the conventional prone approach, particularly in patients with obesity or cardiopulmonary comorbidities. Despite supporting evidence, adoption remains limited due to perceived technical challenges. This study evaluates the surgical outcomes, safety, and efficiency of supine PCNL.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA retrospective observational study was conducted on 120 adults undergoing supine PCNL between January 2023 and January 2024 at a tertiary care centre. Patients were positioned in the Galdakao-modified supine Valdivia position. Primary outcomes included operative and anaesthesia times, stone clearance rate, complications (Clavien–Dindo classification), and hospital stay. Secondary outcomes were perioperative haemoglobin change and transfusion requirements.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMean patient age was \u0026gt; 40 years. Stones \u0026gt; 1500 mm³ occurred in 54.2%. Complete stone clearance was achieved in 95% of patients. Mean operative time was 64.04 ± 16.63 min, and mean anaesthesia time was 81 ± 18.63 min. Mean haemoglobin drop was 0.579 g/dL. Complication rate was 5.7%, predominantly Clavien–Dindo Grade I–II; no organ injuries occurred. Blood transfusions were required in 4.2% (\u003cem\u003ep\u003c/em\u003e = 0.04). Most patients (96.7%) were discharged on postoperative day 2 .\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSupine PCNL achieves high stone clearance rates, shorter operative and anaesthesia times, and low complication rates (p \u0026lt; 0.001 for haemoglobin drop), even in obese and comorbid patients. These findings support its broader adoption as a safe, efficient alternative to prone PCNL in nephrolithiasis management.\u003c/p\u003e","manuscriptTitle":"Supine Percutaneous Nephrolithotomy: A Retrospective Analysis of Surgical Outcomes, Safety, and Efficiency in a High-Risk Population","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-10 15:32:49","doi":"10.21203/rs.3.rs-7645380/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":"d9be12d0-e7c4-4293-a109-5852b9eb6237","owner":[],"postedDate":"October 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-10-17T16:38:38+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-10 15:32:49","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7645380","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7645380","identity":"rs-7645380","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}