Kidney sparing during surgical treatment of an adrenocortical carcinoma with renal vein invasion in a cat.

A 15-year-old domestic shorthair cat was presented with gastrointestinal signs, polyuria, polydipsia, and weakness. Abdominal bruit ("whooshing" sound from turbulent blood flow) and hypertension (systolic blood pressure: 200 mmHg) were present. A left adrenal gland mass was detected with abdominal ultrasonography; a subsequent CT examination identified a mass and a thrombus in the ipsilateral renal vein. Adrenalectomy and venotomy were completed but nephrectomy was not necessary. Histological diagnosis was an adrenocortical carcinoma. There were no clinical signs at a follow-up examination 30 mo after surgery. Key clinical message: This report describes successful surgical management of feline adrenocortical carcinoma with renal vein invasion without kidney damage. This case suggests that, after correct diagnosis and in well-selected cases, surgery to remove adrenal tumors and thrombi in cats, despite renal vein invasion, can be done with excellent short- and long-term outcomes.

Sauvegarde des reins lors du traitement chirurgical d'un carcinome corticosurrénalien avec invasion des veines rénales chez un chatUn chat domestique à poil court de 15 ans a été présenté avec des signes gastro-intestinaux, une polyurie, une polydipsie et une faiblesse. Des bruits abdominaux (« sifflement ¼ provenant d'un flux sanguin turbulent) et une hypertension (pression artérielle systolique: 200 mmHg) étaient présents. Une masse de la glande surrénale gauche a été détectée à l'échographie abdominale; un examen tomodensitométrique ultérieur a identifié une masse et un thrombus dans la veine rénale ipsilatérale. La surrénalectomie et la veinotomie ont été réalisées mais la néphrectomie n'a pas été nécessaire. Le diagnostic histologique était un carcinome corticosurrénalien. Il n'y avait aucun signe clinique lors d'un examen de suivi 30 mois après l'intervention chirurgicale.Message clinique clé:Ce rapport décrit la prise en charge chirurgicale réussie du carcinome corticosurrénalien félin avec invasion des veines rénales sans lésion rénale. Ce cas suggère qu'après un diagnostic correct et dans des cas bien sélectionnés, une intervention chirurgicale visant à éliminer les tumeurs surrénales et les thrombi chez les chats, malgré l'invasion des veines rénales, peut être réalisée avec d'excellents résultats à court et à long terme.(Traduit par Dr Serge Messier).

Simulators in urology resident's training in retrograde intrarenal surgery.

PURPOSE: To evaluate the impact of simulators on the training of urology residents in retrograde intrarenal surgery (RIRS). METHODS: The study involved training eight urology residents, using two artificial simulators; one developed by the Universidade Estadual do Pará, using three-dimensional printing technology, and the other one patented by the medical equipment manufacturer Boston Scientific The qualification of residents took place through a training course, consisting of an adaptation phase (S0), followed by three training sessions, with weekly breaks between them (S1, S2 and S3). Study members should carry out a RIRS in a standardized way, with step-by-step supervision by the evaluator using a checklist. The participants' individual performance was verified through a theoretical assessment, before and after training (pre- and post-training), as well as by the score achieved in each session on a scale called global psychomotor skill score. In S3, residents performed an analysis of the performance and quality of the simulation, by completing the scale of student satisfaction and self confidence in learning (SSSCL). RESULTS: At the end of the course, everyone was able to perform the procedure in accordance with the standard. The training provided a learning gain and a considerable improvement in skills and competencies in RIRS, with p < 0.05. SSSCL demonstrated positive feedback, with an overall approval rating of 96%. CONCLUSIONS: Artificial simulators proved to be excellent auxiliary tools in the training of urology residents in RIRS.

Laparoscopic removal of retroperitoneal schwannoma in renal hilum: a case report.

BACKGROUND: Schwannomas in the renal hilum are rare among retroperitoneal tumors. However, the possibility of malignant findings cannot be ruled out, and surgery is often indicated. This case was expected to be difficult to remove laparoscopically because the tumor was sandwiched between the arteriovenous veins of the renal portal. Sometimes, the tumor should be resected with a conservative approach to the kidney to preserve the renal function. CASE PRESENTATION: Our patient was a 51-year-old Asian-Japanese man who was referred to our department for a retroperitoneal tumor in the renal hilum. Since malignancy could not be ruled out due to its size (45 × 48 × 55 mm) on imaging, the tumor was excised laparoscopically. Histopathology revealed schwannoma. CONCLUSIONS: We herein report a case in which a renal hilar tumor between renal arteriovenous vessels was successfully resected laparoscopically.

Evaluation of the suitability of using ArtiSential in various renal surgery: IDEAL stage 1 study.

BACKGROUND: ArtiSential, a new articulating laparoscopic instruments, addresses the limited movement associated with conventional laparoscopic instruments. This study was conducted to assess the clinical effectiveness of ArtiSential in detailed steps of various renal surgery. METHODS: This study was approved by the Institutional Review Board of our institution and registered on the Clinical Research Information Service site of the Korea Disease Control and Prevention Agency. Participants meeting all inclusion and exclusion criteria were included in the clinical trial and underwent renal surgery. The clinical effectiveness of ArtiSential was assessed in terms of the feasibility and objective and subjective parameters across 9 detailed steps. RESULTS: Of the 15 potential candidates enrolled from October 2021 to November 2021, 1 patient dropped out due to anaphylaxis from an anesthetic agent, and 14 patients underwent laparoscopic surgery using ArtiSential. Of the 14 patients, 2 patients were converted to laparoscopic surgery using straight-shaped instruments due to the ischemia time exceeding 30 min, and 1 patient due to excessive bleeding. The feasibility for most steps was more than 90%, except the renorrhaphy step. The median total operation time and ischemia time were 161 and 23 min, respectively. The median estimated blood loss was 58.5 mL. Two cases of venous injury occurred during renal pedicle dissection step. The accuracy of the procedure judged by reviewers and usability judged by the operator were acceptable in all steps. The surgeon's quantitatively measured stress score was the highest during renorrhaphy step. CONCLUSIONS: Laparoscopic surgery using ArtiSential is feasible for most steps except the renorrhaphy step. The difficulty of performing renorrhaphy is attributed to prolonged ischemia time, which could be addressed by overcoming the learning curve. TRIAL REGISTRATION: Clinical Research Information Service site of the Korea Disease Control and Prevention Agency, KCT0006532. Registered 03/09/2021, https://cris.nih.go.kr/cris/search/detailSearch.do?seq=24071 .

Functional outcomes in robot-assisted partial nephrectomy with three-dimensional images reconstructed from computed tomography: a propensity score-matched comparative analysis.

Our objective was to investigate the long-term functional outcomes of robot-assisted partial nephrectomy (RAPN) combined with three-dimensional (3D) imaging. The 3D images, reconstructed using computed tomography, were introduced in RAPN procedures. The demographic, oncological, functional, and volumetric outcomes of 296 patients who underwent RAPN with and without 3D imaging between 2013 and 2021 were analyzed retrospectively. Propensity score matching (1:1) was performed to adjust for potential baseline confounders. After matching, 71 patients were allocated to each group. In the 3D RAPN (3DRPN) group, functional outcomes significantly improved: the number of patients with over 90% estimated glomerular filtration rate (eGFR) preservation rate (40 vs. 43, P = 0.044), eGFR preservation rate (88.0% vs. 91.6%, P = 0.006), the number of patients with chronic kidney disease (CKD) upstaging (26 vs. 13, P = 0.023), and split renal function preservation rate (operated kidney: 84.9% vs. 88.5%, P = 0.015). The 3DRPN group showed superiority in terms of >90% eGFR preservation (P = 0.010), CKD upstaging-free survival rates (P < 0.001), and volumetric outcomes (excess parenchymal volume: 27.9 vs. 17.7 mL, P = 0.030; parenchyma volume preservation rate: 81.6% vs. 88.8%, P = 0.006). Three-dimensional imaging was positively associated with eGFR preservation (P = 0.023, odds ratio: 2.34) and prevention of CKD upstaging (P = 0.013, odds ratio: 2.90). In this study, RAPN combined with 3D imaging underscored the preservation of eGFR > 90% and the prevention of CKD upstaging by improving the preservation rate of renal parenchyma and split renal function.

[Laparoscopic nephrectomies and kidney resections in children]. / Nachal'nyi opyt laparoskopicheskikh nefrektomii i rezektsii pochek u detei.

OBJECTIVE: To present the experience of laparoscopic nephrectomies and kidney resections in children. MATERIAL AND METHODS: There were 28 minimally invasive surgeries for renal tumors between July 2015 and March 2023 (92 months). There were 16 (57%) boys and 12 (43%) girls who underwent 22 nephrectomies and 6 kidney resections. The median age of patients was 54 (38; 76.5) months. RESULTS: In the laparoscopic nephrectomy group, the median surgery time was 135 (108-188) min, blood loss - 10 (3.75-15) ml. Total resection was confirmed in all patients. In the group of minimally invasive kidney resections, these values were 182.5 (157.5; 265) min and 50 (42.5; 117.5) ml, respectively. Histological examination confirmed total resection in all patients. In both groups, none patient developed postoperative complications. Event-free survival was 86.72% with a median follow-up of 82 months, and local recurrence-free survival was 95.8% with a median follow-up of 89.8 months. CONCLUSION: Minimally invasive nephrectomies and resections are safe in children in case of careful patient selection.

Comparison of the effects of Ho: YAG laser virtual Basket™ pulse modulation and Thulium fiber laser on kidney tissue - an ex vivo experimental study.

Through an ex vivo experimental study, we aimed to compare the effects of the Ho: YAG laser Virtual Basket (VB™) modulation and a Thulium fiber laser (TFL) on kidney tissue in different environments and using laser configurations. The 100 W Ho: YAG (Cyber Ho, Quanta System, Italy) and 60 W TFL (Fiber Dust, Quanta System, Italy) laser devices were used. The following laser settings were selected: power in the range of 10-60 W, frequency of 20-40 Hz, and energy of 0.5-1-1.5 J. A medium pulse duration of 600 µsec was used for VB™, while short (spdTFL; 50 µsec) and long (lpdTFL; 15,000 µsec) were used for TFL. The tissue's incision depth (ID), vaporization area (VA), coagulation area (CA), total laser area (TLA = VA + CA), surface section (SS), and lateral effect (LE) were measured. In total, 108 experiments were conducted. No statistically significant difference in mean VA, TLA, ID, LE, or SS was observed between VB™, spdTFL, and lpdTFL in the low-power output group in saline (p > 0.05). However, the mean CA was statistically significantly higher for VB™ (p = 0.005). In saline and high-power output group, the mean VA, CA, TLA, LE, and ID were higher when using lpdTFL than other pulse durations (p = 0.001, p = 0.001, p = 0.001, p = 0.006, and p = 0.001, respectively). Similar to lpdTFL, VB™ may provide controlled dissection and incision as well as haemostasis. At different laser settings, the individual effects of laser properties (such as pulse length, energy and frequency) on tissue may be more significant.

Donor Kidney With Complete Duplication of Ureter: Is It Safe for Transplantation?

Renal transplantation is the best modality of treatment for patients with end-stage renal disease. Donor shortage remains a substantial problem, for which different strategies are employed, including acceptance of marginal donors and donor kidneys with anatomic variations. We performed a successful kidney transplant of a donor kidney that had complete duplication of the ureter. After transplant, the recipient had no urinary complications.

Effects of perirenal fat thickness on postoperative renal dysfunction in patients who underwent robot-assisted partial nephrectomy for renal tumours.

BACKGROUND: Despite partial nephrectomy (PN) renal function preservation benefits, postoperative renal dysfunction may occur. Perirenal fat thickness (PFT) is associated with renal dysfunction such as diabetes; however, its role in renal tumour surgery is unclear. This study investigates the role of PFT in renal function after robot-assisted partial nephrectomy (RAPN). METHODS: Pre-operative factors for postoperative renal dysfunction were analysed in 156 patients undergoing RAPN with ≥1-year follow-up. PFT measured using computed tomography categorised patients with PFT >21.0 mm (median) as high-PFT. RESULTS: Tumour size, total R.E.N.A.L. nephrometry score and its N component, renal calyx opening, achievement of trifecta, and PFT were risk factors for renal dysfunction 1 year postoperatively. Age ≥75 years (p = 0.024), total RNS ≥7 (p = 0.036), and PFT >21.0 mm (p = 0.002) significantly correlated with postoperative renal dysfunction. CONCLUSIONS: CT-measured PFT is a valuable predictor of postoperative renal dysfunction.

Comparison of surgical outcomes of robot-assisted laparoscopic partial nephrectomy performed by a single experienced surgeon according to two reconstruction methods, including single-layer and double-layer renorrhaphy.

This study aimed to assess the surgical outcomes of single-layer versus double-layer renorrhaphy in robot-assisted laparoscopic partial nephrectomy (RAPN) performed by an experienced surgeon.We enrolled 655 patients who underwent RAPN between January 2019 and June 2023. After excluding those with multiple tumors or incomplete medical records, 554 patients were included in the final analysis. We compared surgical outcomes between single-layer renorrhaphy (outer cortical closure) and double-layer renorrhaphy (inner layer suture and outer cortical closure), adjusting for preoperative factors such as sex, age, body mass index, American Society of Anesthesiologists score, preoperative estimated glomerular filtration rate (eGFR), preoperative complications (diabetes or hypertension), surgical approach (transperitoneal or retroperitoneal), tumor size, and tumor complexity, using propensity score matching. Of the 554 patients analyzed, 59 were classified into the single-layer group and 495 into the double-layer group. Before matching, the double-layer group had more complex and larger tumors. After matching, 58 patients were included in each group. The single-layer group showed significantly shorter operative times (91 min vs. 100 min, p = 0.0361), lower estimated blood loss (EBL) (7.9 ml vs. 27 ml, p = 0.021), and better preservation of eGFR (- 1.2% vs. - 5.1%, p = 0.0313). Other outcomes, such as perioperative complications and postoperative hospital stay, were not significantly different between the groups. Single-layer renorrhaphy demonstrated better surgical outcomes, including shorter operative time, lower EBL, and better preservation of kidney function, compared to double-layer renorrhaphy. These findings suggest that single-layer reconstruction may optimize RAPN outcomes in selected patients.

Utilization of Ureteral Access Sheath in Retrograde Intrarenal Surgery: A Systematic Review and Meta-Analysis.

Background and Objectives: This paper evaluates the efficacy and safety of ureteral access sheath (UAS) utilization in retrograde intrarenal surgery (RIRS). Materials and Methods: We searched PubMed, Embase, and the Cochrane Library up to 30 August 2023. The inclusion criteria comprised English-language original studies on RIRS with or without UAS in humans. The primary outcome was SFR, while the secondary outcomes included intraoperative and postoperative complications, the lengths of the operation and the hospitalization period, and the duration of the fluoroscopy. Subgroup analyses and a sensitivity analysis were performed. Publication bias was assessed using funnel plots and Egger's regression tests. Dichotomous variables were analyzed using odds ratios (ORs) with 95% confidence intervals (CIs), while mean differences (MDs) were employed for continuous variables. Results: We included 22 studies in our analysis. These spanned 2001 to 2023, involving 12,993 patients and 13,293 procedures. No significant difference in SFR was observed between the UAS and non-UAS groups (OR = 0.90, 95% CI 0.63-1.30, p = 0.59). Intraoperative (OR = 1.13, 95% CI 0.75-1.69, p = 0.5) and postoperative complications (OR = 1.29, 95% CI 0.89-1.87, p = 0.18) did not significantly differ between the groups. UAS usage increased operation times (MD = 8.30, 95% CI 2.51-14.10, p = 0.005) and fluoroscopy times (MD = 5.73, 95% CI 4.55-6.90, p < 0.001). No publication bias was detected for any outcome. Conclusions: In RIRS, UAS usage did not significantly affect SFR, complications, or hospitalization time. However, it increased operation time and fluoroscopy time. Routine UAS usage is not supported, and decisions should be patient-specific. Further studies with larger sample sizes and standardized assessments are needed to refine UAS utilization in RIRS.

Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study.

Management of large pediatric kidney calculi (PKC) is challenging. This study aimed to evaluate the efficacy and safety of miniature endoscopic combined intrarenal surgery (mini-ECIRS) for PKC. We retrospectively analyzed mini-ECIRS in 16 pediatric patients undergoing kidney stone treatment between November 2014 and October 2023 to determine its safety, efficacy, and associated outcomes. The median age was 50.50 (interquartile range: 36.75, 84.75) months, and the mean stone size was 21.63 ± 11.65 mm. The stone-free rate was 81.25%. The median decrease in hemoglobin level on the day after surgery was 1.10 (0.80, 1.55), and no patient required a blood transfusion. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Postoperative complications included fever in two patients and difficulty in removing the ureteral stent in one patient. In this cohort, five patients underwent pre-stenting under general anesthesia before mini-ECIRS. Age was significantly lower in the pre-stenting group than in the non-pre-stenting (P < 0.01); however, there were no significant differences in operative time, stone-free rate, total number of general anesthesia procedures, hemoglobin loss, or postoperative hospital stay between the groups. Mini-ECIRS was found to be a safe and efficient treatment method with a high stone removal rate in pediatric patients.

Spectral characterization of intraoperative renal perfusion using hyperspectral imaging and artificial intelligence.

Accurate intraoperative assessment of organ perfusion is a pivotal determinant in preserving organ function e.g. during kidney surgery including partial nephrectomy or kidney transplantation. Hyperspectral imaging (HSI) has great potential to objectively describe and quantify this perfusion as opposed to conventional surrogate techniques such as ultrasound flowmeter, indocyanine green or the subjective eye of the surgeon. An established live porcine model under general anesthesia received median laparotomy and renal mobilization. Different scenarios that were measured using HSI were (1) complete, (2) gradual and (3) partial malperfusion. The differences in spectral reflectance as well as HSI oxygenation (StO2) between different perfusion states were compelling and as high as 56.9% with 70.3% (± 11.0%) for "physiological" vs. 13.4% (± 3.1%) for "venous congestion". A machine learning (ML) algorithm was able to distinguish between these perfusion states with a balanced prediction accuracy of 97.8%. Data from this porcine study including 1300 recordings across 57 individuals was compared to a human dataset of 104 recordings across 17 individuals suggesting clinical transferability. Therefore, HSI is a highly promising tool for intraoperative microvascular evaluation of perfusion states with great advantages over existing surrogate techniques. Clinical trials are required to prove patient benefit.

The postoperative renal function of persistent cloaca patients treated by posterior sagittal anorecto-urethro-vaginopalsty: results of a nationwide survey in Japan.

PURPOSE: We investigated the postoperative renal function in persistent cloaca (PC) patients who underwent posterior sagittal anorecto-urethro-vaginopalsty (PSARUVP) and factors influencing the renal functional outcomes. METHODS: A questionnaire survey was distributed to 244 university and children's hospitals across Japan. Of the 169 patients underwent PSARUVP, 103 patients were enrolled in the present study. Exclusion criteria was patients without data of renal prognosis. RESULTS: The present study showed that renal anomalies (p = 0.09), vesicoureteral reflux (VUR) (p = 0.01), and hydrocolpos (p = 0.07) were potential factors influencing a decline in the renal function. Approximately half of the patients had a normal kidney function, but 45.6% had a reduced renal function (Stage ≥ 2 chronic kidney disease: CKD). The incidence of VUR was significantly higher in the renal function decline (RFD) group than those in the preservation (RFP) group (p = 0.01). Vesicostomy was significantly more frequent in the RFD group than in the RFP group (p = 0.04). Urinary tract infections (p < 0.01) and bladder dysfunction (p = 0.04) were significantly more common in patients with VUR than in patients without VUR. There was no association between the VUR status and the bowel function. CONCLUSIONS: Prompt assessment and treatment of VUR along with bladder management may minimize the decline in the renal function.

White-light activatable organic NIR-II luminescence nanomaterials for imaging-guided surgery.

While second near-infrared (NIR-II) fluorescence imaging is a promising tool for real-time surveillance of surgical operations, the previously reported organic NIR-II luminescent materials for in vivo imaging are predominantly activated by expensive lasers or X-ray with high power and poor illumination homogeneity, which significantly limits their clinical applications. Here we report a white-light activatable NIR-II organic imaging agent by taking advantages of the strong intramolecular/intermolecular D-A interactions of conjugated Y6CT molecules in nanoparticles (Y6CT-NPs), with the brightness of as high as 13315.1, which is over two times that of the brightest laser-activated NIR-II organic contrast agents reported thus far. Upon white-light activation, Y6CT-NPs can achieve not only in vivo imaging of hepatic ischemia reperfusion, but also real-time monitoring of kidney transplantation surgery. During the surgery, identification of the renal vasculature, post-reconstruction assessment of renal allograft vascular integrity, and blood supply analysis of the ureter can be vividly depicted by using Y6CT-NPs with high signal-to-noise ratios upon clinical laparoscopic LED white-light activation. Our work provides efficient molecular design guidelines towards white-light activatable imaging agent and highlights an opportunity for precision imaging theranostics.

Minimising warm ischaemia time during robot-assisted partial nephrectomy. A video-based assessment of tumour excision, kidney reconstruction and intermediate time.

INTRODUCTION: Surgical video review is an emerging tool for assessing patient outcomes, especially in complex surgeries such as robot-assisted partial nephrectomy (RAPN). Assessing and measuring warm ischaemia time (WIT) during RAPN by dividing it into the time used for tumour excision time (ExcT), time used for kidney reconstruction time (RecT) and intermediate time (IntT) has not been performed before. This study aimed to analyse the factors that can influence all surgical times and assess their impact on positive surgical margins (PSMs) and complication rates. METHODS: We evaluated 32 surgical video recordings from patients undergoing RAPN and measured WIT, ExcT, RecT and IntT with a stopwatch. Factors such as tumour characteristics and surgeon experience were also recorded. SPSS software was used to identify the predictors for all surgical times and to correlate ExcT with PSM and RecT with complication rate. RESULTS: We recorded a median WIT of 1,048 s (17 min and 28 s). The median of ExcT, RecT and IntT was 398 s (37.1% of WIT), 518 s (46.7% of WIT) and 180 s (16.2% of WIT), respectively. We found a significant correlation (P < 0.001) between R.E.N.A.L. score and all surgical times. No correlation was found between ExcT and PSM (P = 0.488) and between RecT and the probability of developing complications (P = 0.544). CONCLUSION: Tumour morphology influences all surgical times, and surgeon experience influences only ExcT. We observed a short RecT during RAPN though at the cost of increased ExcT, and we believe that improving surgical experience, especially for the excision of more complex tumours, can reduce WIT during RAPN.

Follow-up After Donor Nephrectomy in Living Kidney Donors: How to Manage Living Kidney Donors Postoperatively.

BACKGROUND/AIM: This study investigated the follow-up rate of living kidney donors and explored the factors related to continuous follow-up and remnant renal function, enabling the optimal management of living kidney donors. PATIENTS AND METHODS: We retrospectively evaluated 180 living kidney donors who underwent donor nephrectomies at our institute. Clinical information was obtained from medical charts, and remnant renal function was defined as the estimated glomerular filtration rate 12 months after donor nephrectomy. RESULTS: Overall, 6/180 donors (3.3%) were lost to follow-up within a year, and the follow-up rate gradually declined yearly. Independent risk factors for loss to follow-up included a follow-up period <60 months and graft survival of the recipient (p=0.002 and p=0.043, respectively). Recipient survival was correlated with loss to follow-up; however, this was not significant (p=0.051). Regarding remnant renal function, age ≥60 years, preoperative estimated glomerular filtration rate <74 ml/min/1.73 m2, and a Δsingle-kidney estimated glomerular filtration rate <9.3 ml/min/1.73m2 were independent risk factors for poorly preserved remnant renal function (p=0.036, p<0.0001, and p<0.0001, respectively). Using propensity score matching to adjust for preoperative factors, a Δsingle-kidney estimated glomerular filtration rate <9.3 ml/min/1.73 m2 was the only significant postoperative factor for poorly preserved remnant renal function (p=0.023). CONCLUSION: An increased 5-year follow-up rate could lead to an increase in long-term follow-up, and recipient prognosis may be correlated with the living kidney donor follow-up status. Furthermore, Δsingle-kidney estimated glomerular filtration rate was identified as a factor for establishing the optimal precision follow-up management of living kidney donors.

Effect of access sheath diameter used in percutaneous nephrolithotomy on renal function: a prospective randomized study.

We aimed to determine the effect of the access sheath diameter used in percutaneous nephrolithotomy (PNL) on renal function. We also investigated the predictors of impaired renal function. Data were prospectively collected from patients who underwent PNL from December 2020 to December 2021. The patients were randomized into two groups according to access sheath diameter: Group 1 (22 Fr, n = 44) and Group 2 (28 Fr, n = 44). Relative renal function (RRF) was calculated by technetium-99 m dimercaptosuccinic acid scintigraphy, and glomerular filtration rate (GFR) was calculated by diethylenetriamine pentaacetic acid scintigraphy. A difference of 5% or more in RRF was considered a significant functional change. Preoperative and postoperative Kidney Injury Molecule-1 (KIM-1) levels were measured. Preoperative demographic data and stone characteristics were similar between the groups. There were also no statistically significant differences between the groups in terms of scar development, changes in RRF, GFR, or KIM-1/creatinine (Cr) (p > 0.05). Significant deterioration in RRF was detected in a total of six (6.8%) patients, three in each group. The factors predicting loss of function were analyzed by regrouping the patients without loss of function as Group A (n = 82) and those with loss as Group B (n = 6). Only stone volume was statistically significant in multivariate analysis (p = 0.002). Access sheath diameter had no significant effect on renal function after PNL. However, the stone volume was found to independently correlate to a loss of renal function after PNL.