Relocation of lower pole renal stones helps improve the stone-free rate during flexible ureteroscopy with a low complication rate.

OBJECTIVE: To compare the efficacy and safety of relocating the lower pole stones to a favorable pole during flexible ureteroscopy with in situ lithotripsy for the treatment of 10-20 mm lower pole stone (LPS). METHODS: This study was a prospective analysis of patient outcomes who underwent an FURS procedure for the treatment of 10-20 mm lower pole renal stones from January 2020 to November 2022. The patients were randomized into a relocation group or in situ group. The LPSs were relocated into a calyx, during lithotripsy in the relocation group was performed, whereas the in situ group underwent FURS without relocation. All the procedures were performed by the same surgeon. The patients' demographic data, stone characteristics, perioperative parameters and outcomes, stone-free rate (SFR), complications, and overall costs were assessed retrospectively. RESULTS: A total of 90 patients were enrolled and analyzed in this study (45 per group) with no significant differences between the two groups in terms of age, gender, BMI, diabetes, hypertension, stone size, number, laterality, composition, and density. The mean operation time, total energy consumption, postoperative stay, and complications were similar between the groups. Both groups had similar SFR at 1 day postoperative follow-up (p = 0.091), while the relocation group achieved significantly higher SFR 3 months later (97.8% vs 84.4%, p = 0.026). The relocation group also had a significantly higher WisQol score than the in situ group (126.98 vs 110.18, p < 0.001). CONCLUSION: A satisfactory SFR with a relatively low complication rate was achieved by the relocation technique during the FURS procedure.

A historical comparison of thulium fiber laser systems for stone lithotripsy: navigating toward safe and effective parameters.

INTRODUCTION AND OBJECTIVES: Medical device companies have introduced new TFL machines, including Soltive (Olympus, Japan), Fiber Dust (Quanta System, Italy), and TFLDrive (Coloplast, France). The primary objective of this study is to compare our initial clinical experiences with TFL using those devices. Through this historical comparison of Thulium Fiber Laser systems for stone lithotripsy, we aim to advance our understanding and approach toward achieving safe and effective TFL parameters. MATERIALS AND METHODS: The data for this comparative analysis were extracted from three distinct prospective series that were previously published, outlining our initial clinical experience with the Soltive (Olympus, Japan), FiberDust laser (Quanta System, Italy), and TFLDrive laser (Coloplast, France). Parameters such as stone size, stone density, laser-on time (LOT), and laser settings were meticulously recorded. Additionally, we assessed critical variables such as ablation speed (expressed in mm3/s) and Joules/mm3 for each lithotripsy procedure. RESULTS: A total of 149 patients were enrolled in this study. Among them, 120 patients were subjected to analysis concerning renal stones. Statistically significant differences were observed in the median (IQR) stone volume: 650 (127-6027) mm3 for TFLDrive, 1800 (682.8-2760) mm3 for Soltive, and 1125 (294-4000) mm3 for FiberDust (p: 0.007); while there were no differences regarding stone density among the groups. Significant variations were identified in median (IQR) pulse energy, frequency, and total power. The Soltive group exhibited lower energy levels (0.3 J vs. 0.6 J, p: 0.002) but significantly higher pulse frequency (100 Hz vs. 17.5 Hz, p: 0.003) and total power (24 W vs. 11W, p: 0.001) compared to the other groups. Laser-on time showed no substantial differences across all three groups. Additionally, a statistically significant difference was observed in median J/mm3, with the TFLDrive group using higher values (24 J/mm3, p: 0.001), while the Soltive group demonstrated a higher median ablation speed of 1.16 mm3/s (p: 0.001). The overall complication rate remained low for all groups, with comparable stone-free rates. CONCLUSION: By reducing pulsed frequency, we improved laser efficiency, but smaller volumes lead to decreased efficiency due to increased retropulsion and fragment movement. Further studies are needed to identify and establish the appropriate laser settings for this new technology.

Pre- and peri-operative clinical information, physiological observations and outcome measures following flexible ureterorenoscopy (FURS), for the treatment of kidney stones. A single-centre observational clinical pilot-study in 51 patients.

BACKGROUND: Kidney stone disease contributes to a significant proportion of routine urological practice and remains a common cause of worldwide morbidity. The main aim of this clinical-pilot study was to investigate the effect of flexible ureterorenoscopy (FURS) on pre- and peri-operative clinical information, physiological observations and outcome measures. METHODS: Included were 51 patients (31 males, 20 females), who underwent elective FURS, for the treatment of kidney stones. Pre-operative and peri-operative clinical information, and post-operative physiological observations and outcome measures were collected using a standard case report form. Pre-operative clinical information included age, gender, BMI, previous history of stone formation and hypertension. Pre-operative stone information included the size (mm), Hounsfield units (HU), laterality and intra-renal anatomical location. Peri-operative surgical details included surgical time in minutes; Laser use; Duration and energy of laser; and post-operative stenting. The physiological outcomes measured included systolic and diastolic blood pressure (mmHg), Likert pain score, temperature, heart rate (bpm) and respiration rate (bpm). Following initial descriptive analysis, a series of Pearson's correlation coefficient tests were performed to investigate the relationship between surgical factors other variable factors. RESULTS: A series of significant, positive correlations were observed between; age and surgical time (p = 0.014, r = 0.373); stone size and Hounsfield unit (p = 0.029, r = 0.406); surgical time and duration of laser (p < 0.001, r = 0.702); surgical time and BMI (p = 0.035, r = 0.322); baseline heart rate and Hounsfield unit (p = 0.026, r = - 0.414); base line heart rate and BMI (p = 0.030, r = 0.307).; heart rate at 120-min post FURS and age (p = 0.038, r = - 0.308); baseline pain score and BMI (p = 0.010, r = 0.361); baseline respiration rate and BMI (p = 0.037, r = 0.296); respiration rate at 240-min post FURS and BMI (p = 0.038, r = 0.329); respiration rate at 120 min post FURS and age (p = 0.022, r = - 0.330). Four patients developed post-operative complications (3-UTIs with urinary retention, 1-urosepsis). CONCLUSIONS: We report that following FURS there is an association between various physiological, clinical and surgical parameters. Although these correlations are weak, they warrant further investigation as these may be linked with untoward complications, such as infection that can occur following FURS. This data, however, will need to be validated and reproduced in larger multi-centre studies.

Evaluation of flexible ureteroscope with an omni-directional bending tip, using a JOYSTICK unit (URF-Y0016): an ex-vivo study.

PURPOSE: To compare the range of reach of our newly designed omni-directional ureteroscope (URF-Y0016), compared to the commonly used URF-P6, FlexX2s, and LithoVue™ scopes, in the upper, middle, and lower calyces in an ex-vivo pyelocaliceal model. METHODS: We fabricated a three-dimensional pyelocaliceal model of the upper, middle, and lower pole calyces using urethane and acrylic resin. The inner surface of the dome of each calyx was engraved with reference lines along eight directions, set at 10° of latitude from the top to the base of the dome, and at angles of 0-90°, to precisely determine the range of reach of each scope. The main feature of the URF-Y0016 scope is the omni-directional bending of the tip of the flexible ureteroscope, with the control of these four directions integrated into a handgun-type control unit with a joystick. The range of reach within each calyx was measured by four expert surgeons. RESULTS: The URF-Y0016 scope provided a greater range of reach along all directions in the lower pole calyx compared to URF-P6, FlexX2s, and LithoVue™ scopes (p < 0.001), particularly along the anterior-posterior direction in the lower lobe calyx. However, the URF-Y0016 scope did not influence the improvement of reach range in the upper and middle pole calyx compared to URF-P6, FlexX2s, and LithoVue™ scopes (p = 0.08, p = 0.296). CONCLUSION: The novel design of the URF-Y0016 could improve treatment outcomes for calyceal stones in the lower pole in practice.

Comparative outcomes of flexible ureteroscopy and mini-percutaneous nephrolithotomy for pediatric kidney stones larger than 2 cm.

OBJECTIVES: To compare the outcomes of flexible ureteroscopy and mini-percutaneous nephrolithotomy for pediatric kidney stones larger than 2 cm and to show the learning curves for the two procedures. METHODS: A prospectively managed database containing pediatric patients with kidney stones larger than 2 cm from June 2014 to October 2019 was analyzed. The primary outcomes were the efficacy and safety of flexible ureteroscopy and mini-percutaneous nephrolithotomy. Data on patient demographics, treatment details, stone-free rate, and complication rate were collected and compared. Learning curves were generated to estimate the effect of the surgeon's experience on surgical outcomes. RESULTS: The final analysis included 113 pediatric patients who underwent surgery for kidney stones on a total of 126 sides. The stone-free rates for mini-percutaneous nephrolithotomy and flexible ureteroscopy were 80.9% (34/42) and 79.7% (67/84), respectively (P = 0.19). The complication rates for mini-percutaneous nephrolithotomy and flexible ureteroscopy were 52.5% (21/40) and 27.4% (27/73), respectively (P = 0.01). When stone mass was considered, the stone-free rates for mini-percutaneous nephrolithotomy and flexible ureteroscopy for stones with a high mass (>5000 HU*cm2 ) were 83.3% (20/24) and 55.5% (10/18), respectively (P = 0.04). The learning curves showed that the stone-free rates for both mini-percutaneous nephrolithotomy and flexible ureteroscopy increased with the accumulation of cases. A higher stone-free rate could be achieved after approximately 20 mini-percutaneous nephrolithotomy cases and after approximately 50 flexible ureteroscopy cases. CONCLUSIONS: Flexible ureteroscopy has an acceptable stone-free rate and a lower complication rate than mini-percutaneous nephrolithotomy when treating pediatric kidney stones larger than 2 cm. Mini-percutaneous nephrolithotomy is more applicable to stones with a high mass. The stone-free rates achieved after both mini-percutaneous nephrolithotomy and flexible ureteroscopy could be improved with number of cases accumulated.

The role of specific biomarkers, as predictors of post-operative complications following flexible ureterorenoscopy (FURS), for the treatment of kidney stones: a single-centre observational clinical pilot-study in 37 patients.

BACKGROUND: The number of patients diagnosed and subsequently treated for kidney stones is increasing, and as such the number of post-operative complications is likely to increase. At present, little is known about the role of specific biomarkers, following flexible ureterorenoscopy (FURS) for the surgical treatment of kidney stones. The main aim of the study was to evaluate the role of kidney and infection biomarkers, in patients undergoing FURS. METHODS: Included were 37 patients (24 males, 13 females), who underwent elective FURS, for the treatment of kidney stones. Venous blood samples were collected from each patient: pre-operatively, and at 30 min, 2 and 4 h post-operatively. Changes to kidney (NGAL, Cystatin-C) and infection (MPO, PCT) biomarkers was quantified by means of ELISA, Biomerieux mini-vidas and Konelab 20 analysers. RESULTS: Four patients developed post-operative complications (3 - UTIs with urinary retention, 1 - urosepsis. NGAL concentration increased significantly following FURS (p = 0.034). Although no significant changes were seen in Cystatin C, MPO and PCT (p ≥ 0.05) some key clinical observation were noted. Limiting factors for this study were the small number of patients recruited and restriction in blood sampling beyond 4 h. CONCLUSIONS: Although not confirmative, changes seen to biomarkers such as Cystatin C, NGAL and MPO in our observational clinical pilot-study may warrant further investigation, involving larger cohorts, to fully understand the role of these biomarkers and their potential association with post-operative complications which can develop following FURS.

[Flexible ureteroscopy for lower pole renal stones: novel superpulse thulium (TM) fiber laser lithotripsy].

INTRODUCTION: The SuperPulse Thulium (Tm) fiber laser (wavelength of 1.94 m) has been recently introduced as a directed-energy source for urology. Preclinical studies have shown a significant potential of the SuperPulse Tm fiber laser (SP TFL) for lithotripsy. However, clinical reports of using SP TFL to treat urolithiasis are still few and limited. Of special interest are challenging cases, e.g., lower pole stones, when extreme deflection of the instrument is required. OBJECTIVE: To evaluate the effectiveness of the SuperPulse Tm fiber laser in the management of lower pole small calyceal stones during flexible ureteroscopy (F-URS). METHOD: s. The SuperPulse Tm fiber laser device (Urolase 2, IRE Polus, Fryazino, Russia) has been cleared for clinical use by the Ministry of Health of Russian Federation. Study protocol has been approved by the Ethical Review Committee. Between January 2018 and February 2019, 130 patients with kidney stones have undergone Thulium fiber laser lithotripsy during F-URS. We retrospectively analyzed 15 of this patients with a single radiopaque lower pole calculus that were included in the present study. Stone size, stone density, lithotripsy time (from the first to last footswitch press) and "lasering" (laser emission) time were measured. The SP TFL was used for stone disintegration with different settings in dusting and fragmentation modes (0.1 - 4J, 7-300Hz, 6-40W) via a fiber with a 200-m core diameter. Low dose CT scanning was performed on POD 90 to assess SFR. RESULTS: Stone size ranged from 4 to 17 mm and stone density varied from 350 to 1459 HU. The average lithotripsy time was 12 min (3-30 min). The average "lasering" time was 1.3 min (0.4-2.5 min) and the mean hospital stay was 1.1+/-0.3 days. In all cases we reached the lower pole stone containing calyx with a laser fiber. The complication rates were evaluated by using the Clavien-Dindo grading system and did not exceed GII (6.6%). SFR on POD 90 was achieved in 86.6% of cases. CONCLUSIONS: F-URS with SuperPulse Tm fiber laser is safe and effective option in the management of lower pole small calyceal stones. The possibility of using small laser fibers gives better instrument deflection which make possible to reach lower pole calyceal stones even with acute lower pole infundibulopelvic angle (IPA).

Comparative study of the treatment of 20-30 mm renal stones with miniaturized percutaneous nephrolithotomy and flexible ureterorenoscopy in obese patients.

PURPOSE: To evaluate and compare flexible ureteroscopy (f-URS) and mini-percutaneous nephrolithotomy (mPNL) for 20-30 mm renal stones in obese patients regarding efficacy and safety. METHODS: Between May 2011 and June 2017, 254 obese patients who had 20-30 mm kidney stone were consecutively included in the study; 106 patients underwent mPNL and 148 underwent f-URS by the same surgeon. The following parameters were retrospectively assessed: patient and stone characteristics, surgical details, perioperative outcomes, and stone-free rates (SFR). RESULTS: F-URS group was similar to mPNL group in terms of the mean duration of surgery (92.8 ± 26.1 vs 87.4 ± 31.5 min, P = 0.137) and the final SFR (89.1 vs 92.5%, P = 0.381). The f-URS group had significantly shorter postoperative stay (1.0 ± 0.8 vs 4.3 ± 1.7 days, P < 0.001) and lower postoperative complications (11.5 vs 26.4%, P = 0.002). However, the f-URS group had a lower SFR after first session (67.2 vs 87.4%, P < 0.001) and needed more number of procedures (1.5 ± 0.4 vs 1.3 ± 0.4, P < 0.001) than the mPNL group. CONCLUSIONS: MPNL has a higher efficacy (higher SFR after first session and lower number of procedures); however, f-URS offers advantages regarding safety (lower complication rate). Therefore, both options can be offered to obese patients with renal stones from 20 to 30 mm in size. Nevertheless, these results must be confirmed by further prospective randomized trials.

Comparison of miniaturized percutaneous nephrolithotomy and flexible ureterorenoscopy for the management of 10-20 mm renal stones in obese patients.

PURPOSE: To evaluate and compare effectivity and safety of flexible ureteroscopy (F-URS) and mini-percutaneous nephrolithotomy (mPNL) for 10-20 mm renal stones in obese patients. METHODS: Between 2012 and 2015, charts of patients who were treated with F-URS or mPNL for 10-20 mm kidney stone(s) were analyzed. Patients with BMI > 30 kg/m(2) were enrolled into the study. Total of 315 patients were treated with mPNL, and 56 patients were matched our inclusion criteria. In the same period, F-URS was performed in 669 patients, and 157 of them had 10-20 mm kidney stones, and their BMI values were >30 kg/m(2). The patients were retrospectively matched at a 1:1 ratio to index F-URS-mPNL cases with respect to the patient age, gender, ASA score, BMI and size, number, and location of stone. RESULTS: Gender, age, BMI, stone size, stone number, location of stone(s), and ASA scores were similar between groups. The mean operation time was significantly longer in mPNL group (p: 0.021). However, the mean fluoroscopy time was similar (p: 0.270). Hemoglobin drop requiring blood transfusion and angioembolization was performed in two and one patients after mPNL, respectively. Overall complication rate was significantly higher in mPNL group than F-URS group (30.3 vs. 5.3 %, p: 0.001). CONCLUSION: Our results demonstrated that both F-URS and mPNL achieve acceptable stone-free rates in obese patients with 10-20 mm renal stones. However, complication rates were significantly lower in F-URS group.

Optimizing outcome reporting after robotic flexible ureteroscopy for management of renal calculi: Introducing the concept of tetrafecta.

Robotic flexible ureteroscopy (RFURS) has shown encouraging results in terms of stone free rate (SFR) and better ergonomics compared to conventional FURS. However, few studies have reported its outcomes. The goal of this study was to report our initial results of RFURS, furthermore we proposed a novel metrics for composite outcome reporting named tetrafecta. A retrospective analysis of electronic records of 100 patients treated with RFURS for renal stones between 2019 till 2023 was performed. Tetrafecta criteria included, complete stone removal after a single treatment session, without auxiliary procedures, absence of high-grade complications (GIII-V) and same-day hospital discharge. Mean patient age and stone size were 40.7 ± 9.2 and 11.7 ± 5.8 mm, respectively. Median stone volume was 916 (421-12,235) mm3. Twenty-eight patients had multiple renal stones. Staghorn stones were seen in 12 patients. Preoperative DJ stent was fixed in 58 patients. Median operative time and stone treatment time were 116 min (97-148) and 37 (22-69) min. The median stone treatment efficiency (STE) was 21.6 (8.9-41.6). A strong positive correlation between stone volume and STE (R = 0.8, p < 0.0001). Overall, 73 patients were stone free after the initial treatment session while tetrafecta was achieved in 70 patients. Univariate analysis showed that the stone size (p = 0.008), acute infundibulopelvic angle (p = 0.023) and preoperative stenting (p = 0.017) had significant influence on achieving tetrafecta. Multivariate analysis identified preoperative stenting (OR 0.3, 95% CI 0.1-0.8, p = 0.019) as the only independent predictor of tetrafecta achievement. A comprehensive reporting methodology for reporting outcomes of RFURS is indicated for patient counseling and comparing different techniques. Tetrafecta was achieved in 70% of cases. Presence of significant residual stones ≥ 3mm was the leading cause of missing tetrafecta. Absence of preoperative stent was the only predictor of missing tetrafecta.

Ureteral stone volume and female gender predicts perioperative complications after complete ipsilateral upper urinary tract stone removal using flexible ureterorenoscopy.

PURPOSE: To identify the risk factors for perioperative complications to prevent perioperative complications after complete ipsilateral upper urinary stone removal using flexible ureterorenoscopy. MATERIALS AND METHODS: We retrospectively examined 111 patients who underwent flexible ureterorenoscopy for ipsilateral renal stones with a diameter ≥ 5 mm at the same time as ureterorenoscopy for ureteric stones. The flexible ureterorenoscopy procedures were performed following the fragmentation technique. Patients who experienced (complication group) and did not experience (non-complication group) perioperative complications were compared. The complication group included 33 patients with Clavien-Dindo classification scores of I, II, III, or IV and/or those with a body temperature of > 37.5 â„ƒ during hospitalization. RESULTS: The overall stone volume, stone-free rate and procedure duration were 1.71 mL, 96.4% and 77 min, respectively. The rate of perioperative complications was 29.7% (grade 1, 2 and 3 was 23.4%, 5.4% and 0.9%, respectively). Severe complications (Clavien-Dindo grade 4) were not observed. Multivariable analysis revealed that ureteral stone volume and female patients were independent predictors of perioperative complications after flexible ureterorenoscopy (p = 0.015 and 0.017, respectively). CONCLUSIONS: This study showed that ureteral stone volume and female gender have the possibility to increase perioperative complications. These preliminary data help to select for patients who are at low risk of complications. Therefore, in these selected patients, complete ipsilateral upper urinary tract stone removal using flexible ureterorenoscopy may reduce the recurrence of urolithiasis without increasing perioperative complications.

Management of deceased and living kidney donor with lithiasis: a multicenter retrospective study on behalf of the renal transplant group of the Spanish urological association.

BACKGROUND: To maximize the availability of suitable grafts and ensure effective management, several reports have demonstrated successful outcomes when using kidney grafts with urolithiasis. This multicenter study reports on the management and long-term outcomes of kidney transplantation using renal grafts with lithiasis. METHODS: Retrospective data from three Spanish hospitals were analyzed for kidney transplants involving grafts with nephrolithiasis performed between December 2009 and August 2023. The study included adult patients, excluding those with incomplete records. It evaluated stone characteristics, complications, and outcomes in recipients and in living kidney donors. RESULTS: Out of 38 analyzed kidney transplants, 57.9% were cadaveric and 42.1% were from living kidney donors. Most diagnoses were incidental during donor evaluation, with an average stone size of 7.06 mm. After follow-up (median 26 months), all recipients but one had functioning grafts, and there were no stone recurrences in both recipients and living kidney donors. Conservative management was adopted in 28 cases, while 10 cases required ex-vivo flexible ureterorenoscopy for stone removal. Following conservative management, 5 patients needed additional treatments for stone-related events. CONCLUSIONS: Kidneys with lithiasis can be considered for transplantation in selected cases, resulting in good functional outcomes with no stone recurrence in recipients or living donors.

Living donor-gifted allograft lithiasis: surgical experience after bench surgery stone removal and follow-up.

This study presents the surgical experience and long-term outcomes of living donor kidney transplantations involving asymptomatic kidney stones, using ex vivo flexible ureterorenoscopy (f-URS) during bench surgery for stone removal. Out of 1743 living kidney donors assessed between January 2012 and October 2022, 18 (1%) were diagnosed with urolithiasis. Among them, 12 donors were rejected, and 6 were accepted for kidney donation. Stone removal was successfully performed using f-URS during bench surgery, with no immediate complications or acute rejections observed. The study analyzed six living kidney transplants, of which 4 (67%) donors and three recipients were female, and 4 (67%) donors were blood-related to the recipient. The median age for donors and recipients was 57.5 and 51.5 years, respectively. The stones, primarily located in the lower calyx, had a median size of 6 mm. The median cold ischemia time during surgery was 41.6 min, and ex vivo f-URS ensured complete stone removal in all cases. After a median follow-up of 120 months, the remaining grafts were functioning well, and no urinary stone recurrence was observed in either the recipients or living donors. The findings suggest that bench f-URS is a safe approach for managing urinary stones in kidney grafts, providing good functional outcomes without stone recurrence in selected cases.

Flexible ureteroscopy under local anesthesia for stone management: initial exploration and two-year experience.

BACKGROUND: Flexible ureteroscopy (f-URS) is a minimally invasive surgical technique used for treating urinary tract stones. While general anesthesia (GA) is the standard method used, it comes with risks. Local anesthesia (LA) is a safer and more cost-effective alternative to GA, and its use in f-URS could potentially reduce patients' risks and increase accessibility to treatment. This study aims to investigate the feasibility, safety, and efficacy of using LA for f-URS in treating stones, as an initial experience in the diagnosis related group (DRG) era of China. METHODS: Patients who met the inclusion and exclusion criteria and were continuously included in the study Between 2021 and 2023. We analyzed the stone free status, postoperative complication rate, hospitalization costs, and presented key points of the procedure performed under LA that we had summarized over the past two years. RESULTS: A study of 614 patients undergoing f-URS under LA for urinary stones in our hospital showed 83.4% stone-free rate with a mean operative time of 44.12 ± 16.63 minutes; 18 patients experienced fever postoperatively, and 12 had ureteral injuries. No severe complication was reported. The cost of LA was found to be only 1.7% of the DRG payment, which is around $40. The highest VAS scores were observed during the sheath insertion, with STAI scores decreasing during and after surgery. CONCLUSIONS: The study revealed that f-URS administered under LA was a well-tolerated, efficient, safe, and economical procedure. In the DRG era, this new anesthetic option for f-URS provides urologists with a more cost-effective alternative.

A robotic system for solo surgery in flexible ureteroscopy: development and evaluation with clinical users.

PURPOSE: The robotic system CoFlex for kidney stone removal via flexible ureteroscopy (fURS) by a single surgeon (solo surgery, abbreviated SSU) is introduced. It combines a versatile robotic arm and a commercially available ureteroscope to enable gravity compensation and safety functions like virtual walls. The haptic feedback from the operation site is comparable to manual fURS, as the surgeon actuates all ureteroscope DoF manually. METHODS: The system hardware and software as well as the design of an exploratory user study on the simulator model with non-medical participants and urology surgeons are described. For each user study task both objective measurements (e.g., completion time) and subjective user ratings of workload (using the NASA-TLX) and usability (using the System Usability Scale SUS) were obtained. RESULTS: CoFlex enabled SSU in fURS. The implemented setup procedure resulted in an average added setup time of 341.7 ± 71.6 s, a NASA-TLX value of 25.2 ± 13.3 and a SUS value of 82.9 ± 14.4. The ratio of inspected kidney calyces remained similar for robotic (93.68 %) and manual endoscope guidance (94.74 %), but the NASA-TLX values were higher (58.1 ± 16.0 vs. 48.9 ± 20.1) and the SUS values lower (51.5 ± 19.9 vs. 63.6 ± 15.3) in the robotic scenario. SSU in the fURS procedure increased the overall operation time from 1173.5 ± 355.7 s to 2131.0 ± 338.0 s, but reduced the number of required surgeons from two to one. CONCLUSIONS: The evaluation of CoFlex in a user study covering a complete fURS intervention confirmed the technical feasibility of the concept and its potential to reduce surgeon working time. Future development steps will enhance the system ergonomics, minimize the users' physical load while interacting with the robot and exploit the logged data from the user study to optimize the current fURS workflow.

Learning Curves of Flexible Ureteroscopy (275 Cases) and Prone Percutaneous Nephrolithotomy (73 Cases) in Pediatric Stones: Data from 348 Children.

Objectives: To evaluate learning curves in pediatric flexible ureteroscopy (FURS) and pediatric prone percutaneous nephrolithotomy (PCNL) by a single surgeon with experience in adult endourologic procedures. Materials and Methods: Children who were found to have nephrolithiasis and treated with PCNL or FURS from June 2014 to April 2019 were analyzed. Patient demographics, stone characteristics, stone-free rate (SFR), and complication rate (CR) were reported. Learning curves were generated to estimate the effect of a surgeon's experience on outcomes. Results: Seventy-three children underwent PCNL on 86 sides in 77 operations and 275 children underwent FURS on 320 sides in 288 operations. The SFRs were 88.1% (282/320) for FURS procedures and 89.5% (77/86) for PCNL procedures. CRs were 19.8% (57/288) and 35.1% (27/77), respectively. Learning curves showed that the SFRs of the two procedures increased with the accumulation of cases. There was an apparent improvement of SFR for PCNL procedures after ∼60 surgeries. A favorable SFR of FURS could be achieved at the start of learning. No apparently decreased CRs were observed for either PCNL or FURS. Conclusions: Both PCNL and FURS could achieve satisfactory SFRs and accepted CRs in pediatric stones. Increased surgical experience was associated with improved SFRs of both PCNL and FURS procedures, and the surgeon's experience of adult FURS translating to that of pediatric FURS was better than adult PCNL translating to pediatric PCNL. A surgeon needs ∼60 cases of PCNL to achieve competence. For FURS, a favorable SFR could be achieved at the start of learning.

Is there a place for extracorporeal shockwave lithotripsy (ESWL) in the endoscopic era?

This retrospective study aimed to evaluate whether there was still a place for ESWL therapy in the endourological era. From 1988 to 2018, ESWL therapy was performed with 3 successive types of lithotripters in our hospital. From 1988 to 1998, the electrohydraulic lithotripter NS-15 was used, and the electromagnetic lithotripter HK-V was put to use in 1999. Since 2010, the electromagnetic lithotripter HK-Vm has been used. Over the 30-year period, 16,969 urolithiasis patients underwent ESWL therapy, including 124 paediatric cases and 178 special cases. The stone clearance rate (SCR) and postoperative complications in the 3 lithotripter groups were recorded and analysed. The SCR was estimated by ultrasonography or plain X-ray, while the complications were recorded by the modified Clavien grading system. The primary stone clearance rate (pSCR) of ureteral and renal stones was significantly improved in the HK-Vm group compared with the NS-15 and HK-V groups. The final stone clearance rate (fSCR) of lower calyx stones was considerably higher in the HK-Vm group (55.9%) than in the NS-15 (41.1%) and HK-V (44.1%) groups. Most complications were grade I and II, while the incidence of grade III and above complications was less than 3%. Additionally, the fSCR in paediatric and special cases ranged from 66.5% to 83.5%, with no record of severe complications. As our data showed, ESWL was effective and safe for most urolithiasis patients, including paediatric patients and special cases. Therefore, ESWL is still the major treatment option in the current endourological era.

Can We Identify Patients in Danger of Complications in Retrograde Intrarenal Surgery?-A Retrospective Risk Factors Analysis.

Retrograde intrarenal surgery (RIRS) is an innovative and effective method of kidney stones treatment, as it had great influence on the development of endoscopy in urology. The increasing prevalence of urolithiasis together with the rapid development of endourology leads to a rise in the number of procedures related to the disease. Flexible ureteroscopy is constantly being improved, especially regarding the effectiveness and safety of the procedure. The purpose of this study is to evaluate intraoperative and early post-operative complications of RIRS in the treatment of kidney stones. A retrospective analysis of medical records was performed. A series was comprised of 207 consecutive operations performed from 2017 to 2020. Complications occurred in 19.3% (n = 40) of patients. Occurrence according to the Clavien-Dindo scale was: 11.1% for grade I, 5.8% for grade II and 2.4% for grade IV. Infectious complications included SIRS (5.3%, n = 11) and sepsis (2.4%, n = 5). Statistical analysis revealed a correlation between acute post-operative infections and positive midstream urine culture, history of chronic or recurrent urinary tract infections, and increased body mass index (BMI). Furthermore, a significant correlation was observed between pain requiring the use of opioids with BMI over 25. Consequently, history of urinary tract infections, positive pre-operative urine culture, and increased BMI are considered risk factors and require appropriate management.

Renal Pseudoaneurysms after Flexible Ureteroscopy and Holmium Laser Lithotripsy: A Case Report.

Background: Flexible ureteroscopy (FURS) and holmium laser lithotripsy is considered one of the most minimally invasive and safe surgical methods for the treatment of renal calculi. Renal pseudoaneurysm is a rare complication after FURS holmium laser lithotripsy. We report a case of renal pseudoaneurysm after FURS and holmium laser lithotripsy and review the relevant literature to analyze the possible etiology and summarize the treatment. Case presentation: A 29-year-old male with a 2-year history of diabetes was admitted to the hospital because of right back pain for 5 days. A doppler ultrasound demonstrated bilateral renal calculi with bilateral mild hydronephrosis. The patient underwent one-stage right FURS and holmium laser lithotripsy and bilateral ureteral stent implantation. The urine was clear on the second day after the operation, and he was discharged from the hospital. Due to severe gross hematuria, he had to be hospitalized 28 days after the operation. A CT scan showed multiple blood clots in the right renal pelvis and bladder. An emergency blood transfusion and removal of the bladder blood clots and bilateral double J tubes were performed. His urine was clear for one week, and he was discharged from the hospital. He was hospitalized again 47 days after the operation because of fever and hematuria. A CT scan demonstrated blood clots in the bladder and right renal pelvis. Angiography showed a pseudoaneurysm in a small branch of the right renal artery, and hematuria stopped after selective renal artery embolization with microcoils. Conclusion: FURS and holmium laser lithotripsy is safe, but we should be aware of the possibility of renal artery pseudoaneurysms (RAP). Through careful operation during the surgery, avoiding kidney injury, reducing intrarenal pressure and controlling the time of operation may prevent the occurrence of this complication. Vascular embolization is the first choice for the treatment of pseudoaneurysms.

The Neutrophil Gelatinase-Associated Lipocalin (NGAL) as a Biomarker for Monitoring Renal Function in Patients with Solitary Kidney Stones: A Single-Center, Retrospective Analysis of 23 Cases.

PURPOSE: To assess the efficacy of flexible ureteroscopy (F-URS) in treating single kidney stones and the role of Neutrophil Gelatinase-Associated Lipocalin (NGAL) in detecting early renal function abnormalities in patients with solitary kidney stones. MATERIALS AND METHODS: We retrospectively analyzed 23 patients with solitary kidney nephrolithiasis who underwent F-URS at the Sichuan Science City Hospital between January 2017 and November 2020. We collected data on the following variables: Age, gender, stone size, surgery time, perioperative outcomes, and complications; Stone-free rates (SFRs) were calculated using computed tomography (CT). Serum creatinine (SCr) and NGAL levels were tested before surgery and at one-day and one-month postoperatively. RESULTS: The average size of the stones was 1.53 ± 0.57 cm. The average operating time was 59.28 ± 21.25 minutes. For urethral stricture, three patients (13.0%) required second-stage F-URS. The SFRs were 91.3% following the first and second treatments. The mean NGAL levels were significantly increased at one-day postoperatively compared to baseline (768.91 ± 514.50 ng/mL vs. 173.39 ± 147.94 ng/mL, respectively, p < 0.001). Minor complications, including gross hematuria (n = 5) and mild fever (n = 3), occurred in 34.8% of cases (n = 8), who recovered quickly. CONCLUSIONS: F-URS is a safe and efficient therapeutic approach for patients with solitary kidney nephrolithiasis, and NGAL has huge prospects as an indicator of early-stage renal injury in this patient population.