Parapelvic Renal Cyst Treatment with Flexible Ureteroscopy: Single Centre Experience.

BACKGROUND: This study aimed to assess the feasibility, safety, and efficacy of an endoscopic parapelvic renal cyst (PRC) incision using flexible ureterorenoscopy (fURS). MATERIAL AND METHODS: We retrospectively reviewed data concerning 16 patients in whom PRC incisions had been performed using fURS between January 2016 and January 2022. Two patients were excluded from the study owing to a lack of follow-up information. The cysts of all the patients were evaluated preoperatively by computed tomography. The patients' age, gender, cyst size, presenting symptoms, postoperative complications, and pre- and post-treatment visual analogue scale (VAS) scores were evaluated. Surgical success was defined as a reduction of more than half of the cyst size in the sixth postoperative month. RESULTS: A total of 14 patients were included in this study. The patients' mean age was 52.6 ± 8.8 years, and the mean cyst size was 69.1 ± 15.5 mm. Twelve (85.7%) patients presented with flank pain. Clavien-Dindo grade 1 complications were observed in two patients (14.3%), and grade 2 complications were observed in one (7.1%). The median VAS scores were significantly lower after treatment than before in patients who presented with flank pain (2 (1-2.8) vs 8 (7-8), respectively; p = 0.002). Surgical success rate was detected in 11 patients (78.6%) six months after the treatment. CONCLUSIONS: Endoscopic incision of the PRC is a feasible treatment modality with high success rates and low complication rates. However, multicentre studies with larger populations and longer follow-ups are needed to evaluate the lasting effects.

Being all-seeing gymnast within kidney cavity: analysis of the optical and flexibility characteristics trends of 61 flexible ureteroscopes over four decades.

The purpose of this review is to analyze the trend in optical features and flexibility changes of flexible ureteroscopes over the past decades, and determine the correlation of individual parameters with release period as well as with dimensional parameters. Flexible ureteroscopes mentioned in the literature or those commercially available were searched. To minimize the search bias, the instruments were grouped by release date time-periods of < 2000 year, 2000-2009, 2010-2019, and 2020 onwards. The final review included only those instrument models for which data on minimum and maximum depth of field, field of view, direction of view, and deflection degree had been determined. The correlation among features investigated as well as with release period was also determined. 61 models of flexible ureteroscopes (27 fibreoptic and 34 digital scopes) were included. Among the different features investigated among fiberoptic endoscopes, minimum depth of field positively and negatively correlated with channel size and field of view, respectively, whereas maximum depth of view and field of view positively correlated with overall shaft and deflection degree, respectively. Up and down deflection strongly correlated with each other and both were negatively proportional to the distal tip size. For the digital endoscopes, minimum depth of field negatively and positively correlated with distal tip size and working length, respectively. Maximum depth of field positively correlated with field of view, whereas the latter was negatively proportional to the overall shaft. As for the fiberoptic counterparts, up and down deflection strongly correlated with each other. Field of view, up and down deflection of fiberoptic flexible ureteroscopes, were significantly increased among fiberoptic and digital endoscopes over decades. As flexible ureteroscopy technology has evolved, there has been a trend towards increasing field of view with up and down deflection. Given the importance of scope ergonomics, one aspect of this popularity is the improvement of optical characteristics and deflection degree, which significantly correlates with the release period.

Effect of esketamine on the ED50 of propofol for successful insertion of ureteroscope in elderly male patients: a randomized controlled trial.

BACKGROUND: Propofol is effective and used as a kind of routine anesthetics in procedure sedative anesthesia (PSA) for ureteroscopy. However, respiratory depression and unconscious physical activity always occur during propofol-based PSA, especially in elderly patients. Esketamine has sedative and analgesic effects but without risk of cardiorespiratory depression. The purpose of this study is to investigate whether esketamine can reduce the propofol median effective dose (ED50) for successful ureteroscope insertion in elderly male patients. MATERIALS AND METHODS: 49 elderly male patients undergoing elective rigid ureteroscopy were randomly divided into two groups: SK Group (0.25 mg/kg esketamine+propofol) and SF Group (0.1 µg/kg sufentanil+propofol). Patients in both two groups received propofol with initial bolus dose of 1.5 mg/kg after sufentanil or esketamine was administered intravenously. The effective dose of propofol was assessed by a modified Dixon's up-and-down method and then was adjusted with 0.1 mg/kg according to the previous patient response. Patients' response to ureteroscope insertion was classified as "movement" or "no movement". The primary outcome was the ED50 of propofol for successful ureteroscope insertion with esketamine or sufentanil. The secondary outcomes were the induction time, adverse events such as hemodynamic changes, hypoxemia and body movement were also measured. RESULT: 49 patients were enrolled and completed this study. The ED50 of propofol for successful ureteroscope insertion in SK Group was 1.356 ± 0.11 mg/kg, which was decreased compared with that in SF Group, 1.442 ± 0.08 mg/kg (P = 0.003). The induction time in SK Group was significantly shorter than in SF Group (P = 0.001). In SK Group, more stable hemodynamic variables were observed than in SF Group. The incidence of AEs between the two groups was not significantly different. CONCLUSION: The ED50 of propofol with esketamine administration for ureteroscope insertion in elderly male patients is 1.356 ± 0.11 mg/kg, significantly decreased in comparsion with sufentanil. TRIAL REGISTRATION: Chinese Clinical Trial Registry, No: ChiCTR2300077170. Registered on 1 November 2023. Prospective registration. http://www.chictr.org.cn .

Rigid ureteroscopic lithotripsy with a pressure-controlling ureteral access sheath for complex steinstrasse.

OBJECTIVE: To evaluate the safety and efficacy of rigid ureteroscopic lithotripsy with a pressure-controlling ureteral access sheath (PC-UAS) for complex steinstrasse. METHODS: Thirty-one consecutive patients (male: 18; female: 13) with steinstrasse were enrolled, six of whom had concurrent kidney stones. The mean cumulative stone size was 2.7 ± 1.3 cm. The patients were treated with rigid ureteroscopic lithotripsy using a PC-UAS. The cavity pressure parameters were set as follows: control value at -15 mmHg to -2 mmHg, warning value at 20 mmHg, and limit value at 30 mmHg. The infusion flow rate was set at 150-200 ml/min. A holmium laser (550 µm) was used to powderize the stone at 2.0-2.5 J/pulse with a frequency of 20-30 pulses/s. Analyses included cavity pressure, operative time, stone-free rates, and complications. RESULTS: Among the 31 patients, 29 were successfully treated with PC-UAS, with nine requiring adjunctive flexible ureteroscopy for stone migration to the kidney. Two procedures were converted to percutaneous nephrolithotomies due to failure of sheath placement. The cavity pressure of all 29 patients was well-maintained below 20 mmHg, with clear vision. The mean operative time was 48.2 ± 17.7 min. No complications, such as ureteral perforation, mucosal avulsion, or hemorrhage, occurred. Two cases of Clavien-Dindo grade I complications occurred. No major complications (Clavien-Dindo grade II-V) occurred. The mean postoperative hospitalization time was 1.7 days. The stone-free rates 1 day and 1 month after surgery were 93.1% and 96.6%, respectively. One patient with residual stones underwent extracorporeal shockwaves. CONCLUSIONS: Rigid ureteroscopic lithotripsy with PC-UAS can effectively control the cavity pressure, shorten the operation time, and improve the efficiency of broken stones, thus reducing the complication rate.

Flexible Ureteroscopic Guided Laparoscopic Ureteroplasty For The Treatment Of Ureteral Stricture.

INTRODUCTION: Ureteral stricture is often a consequence of urolithiasis or previous endourological procedures (1-3). Precisely delineating the stricture zone intraoperatively is crucial to minimize ureter shortening and target only the affected tissue (4, 5). Flexible ureteroscopy offers a significant advantage in this regard. OBJECTIVE: This video aims to demonstrate the step-by-step technique of flexible ureteroscopic guided laparoscopic ureteroplasty for treating ureteral stricture caused by urolithiasis and prior endourological interventions. PATIENT AND METHODS: We present a case of a 36-year-old male with a history of urolithiasis and unsuccessful endourological treatments, including endoureterotomy and balloon dilation, diagnosed with re-stenosis of the proximal ureter of 1 cm through ureteroscopy and pyelography. He underwent a successful laparoscopic ureteroplasty. While the lead surgeon performed the laparoscopy, an assistant conducted the flexible ureteroscopy. Intraoperatively, using transillumination facilitated by the flexible ureteroscope, we can precisely identify the narrowed area, allowing for resection of only the damaged segment. Subsequently, we perform the end-to-end ureteroplasty, confirming its patency through the seamless passage of the ureteroscope. Upon completion, we employ a fat patch to safeguard the anastomosis. RESULTS: The patient was discharged on the third postoperative day. Double J stent was removed six weeks after surgery. Symptoms resolved. Renal function improved: eGFR 49 to 67 ml/min. Furthermore, improvement was observed in the DTPA scan, and a decrease in hydronephrosis was noted on the follow-up tomography. CONCLUSION: Flexible ureteroscopy effectively identifies the stricture zone in laparoscopic ureteroplasty, enhancing surgical precision and outcomes. This approach is safe, effective, and reproducible, offering a valuable technique in the surgical treatment of ureteral strictures.

Fluid absorption during flexible ureteroscopy with intelligent control of renal pelvic pressure: a randomized controlled trial.

PURPOSE: To investigate fluid absorption and its influencing factors during flexible ureteroscopy with intelligent control of renal pelvic pressure (RPP). METHODS: A total of 80 patients with upper urinary tract calculi underwent flexible ureteroscopy with intelligent control of RPP by pressure-measuring ureteral access sheath and were randomly divided into four groups. The RPP of Groups A, B, and C were set at - 5, 0 and 5 mmHg, respectively. Conventional flexible ureteroscopy with uncontrolled pressure served as control Group D. The perfusion flow rate was set at 100 ml/min in the four groups, with 20 patients in each group. The fluid absorption was measured by 1% ethanol every 10 min. Operation time, stone-free rate, and complications were recorded. RESULT: Seventy-three patients were finally included in the RCT. The general and preoperative data of the patients were comparable between the groups. The fluid absorption of Groups A, B, and C was significantly less than that of Group D (P < 0.01). Fluid absorption and operation time were positively correlated, and the correlation coefficients R were 0.864, 0.896, 0.918, and 0.947, respectively (P < 0.01). The fluid absorption of patients with vomiting, fever and ureteral injury was greater than that of patients without complications in the four groups (P < 0.01). In different groups, fluid absorption was greater in patients with ureteral injury Post-Ureteroscopic Lesion Scale (PULS) 1-3 than in noninjured patients (P < 0.01). CONCLUSION: Flexible ureteroscopy with intelligent control of RPP effectively reduces the absorption of perfusion fluid. Operation time and ureteral injury are also key factors affecting perfusion fluid absorption. REGISTRATION NUMBER AND DATE: NCT05201599; August 11, 2021.

Illumination matters part IV: blackout and whiteout in flexible ureteroscopy - first report on a phenomenon observed by PEARLS.

PURPOSE: To date, no study has evaluated effects of varying brightness settings on image quality from flexible ureteroscopes submerged in saline. The aim was to evaluate blackout and whiteout occurrences in an in-vitro kidney calyx model. MATERIAL AND METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU WiScope using a 3D-printed enclosed pink in-vitro kidney calyx model submerged in saline. Endoscopic images were captured with ureteroscope tip placed at 5 mm,10 mm and 20 mm distances. The complete range of brightness settings and video capture modes were evaluated for each scope. Distribution of brightness on a grayscale histogram of images was analyzed (scale range 0 to 255). Blackout and whiteout were defined as median histogram ranges from 0 to 35 and 220 to 255, respectively (monitor image too dark or too bright for the human eye, respectively). RESULTS: Blackout occurred with the P7, Pusen 7.5F, 9.2F and WiScope at all distances, and V3 at 20 mm - with lowest brightness settings. Whiteout occurred with Flex-X2s, V3 and P7 at 5 mm and 10 mm, as well as with V3 and P7 at 20 mm - mostly with highest brightness settings. The Flex-Xc had neither blackout nor whiteout at all settings and distances. CONCLUSION: Blackout or whiteout of images is an undesirable property that was found for several scopes, possibly impacting diagnostic and therapeutic purposes during ureteroscopy. These observations form a guide to impact a urologist's choice of instruments and settings.

Illumination matters Part II: advanced comparative analysis of flexible ureteroscopes in a kidney model by PEARLS.

PURPOSE: The aim of the study was to evaluate illumination properties in an in-vitro kidney calyx model in saline. DESIGN AND METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU WiScope using a 3D-printed closed pink kidney calyx model, submerged in saline. A spectrometer was used for illuminance and color temperature measurements at different openings located at center (direct light), 45° (direct and indirect light) and 90°(indirect light) to the axis of the scope. RESULTS: Maximum illuminance was at the center opening for all scopes (range: 284 to 12,058 lx at 50% brightness and 454 to 11,871 lx at 100% brightness settings). The scope with the highest center illuminance (Flex-Xc) was 26 times superior to the scope with the lowest illuminance (Pusen 7.5Fr) at 100% brightness setting. For each scope, there was a peripheral illuminance drop ranging from - 43 to - 92% at 50% brightness and - 43% to - 88% at 100% brightness settings, respectively (all p < 0.01). Highest drop was for the P7 and the Pusen 9.2F. All scopes had illuminance skew, except the V3. All scopes had a warm color temperature. CONCLUSION: Illumination properties vary between ureteroscopes in an enclosed cavity in saline, and differs at center vs 45° and 90° positions within scopes. Peripheral illuminance drop can be as high as - 92%, which is undesirable. This may affect the choice of ureteroscope and light brightness settings used in surgery by urologists.

RETROGRADE INTRARENAL LITHOTRIPSY USING DISPOSABLE FLEXIBLE URETEROSCOPE.

This research aims to characterize efficiency of a flexible ureteroscope that is of single use with regard to surgical time, absence of stone, and complications. From March 2022 to April 2023, the Basrah Urological Centre carried out this anticipated work. After excluding patients with untreated urinary tract infections, excessive blood urea, and ureteral strictures, the study involved ninety-eight patients. All patients were above 20 years of age. Patients were operated on by the same surgeon. This study involved 108 patients in this study composed of 42 (39.8%) men and 65 (60.2%) women. With a standard deviation of 10.9 years, the patient's mean age was 39.2 years. The total stone burden ranged from 6.9 to 14.5 mm, averaging 9.7±2.9 mm. The stone density ranged from 820-1411 HU, averaging 1000.8±279.3 HU. According to the current study, treating renal stones with a single-use flexible ureteroscope is less complicated and more successful.

Illumination matters part I: comparative analysis of light sources and illumination in flexible ureteroscopy-fundamental findings from a PEARLS analysis.

PURPOSE: Illumination characteristics of flexible ureteroscopes have been evaluated in air, but not in saline, the native operative medium for endourology. The aim was to evaluate light properties of contemporary ureteroscopes in air versus saline, light distribution analysis, and color temperature. METHODS: We evaluated the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, and OTU WiScope using a 3D printed black target board in-vitro model submerged in saline. A spectrometer was used for lux and color temperature measurements at different opening locations. RESULTS: Illuminance was higher in saline compared to air (5679 vs. 5205 lx with Flex-Xc, p = 0.02). Illuminance in saline differed between ureteroscopes (ANOVA p < 0.001), with highest for the Flex-Xc at 100% brightness setting (5679 lx), followed by Pusen 9.2F (5280 lx), Flex-X2s (4613 lx), P7 (4371 lx), V3 (2374 lx), WiScope (582 lx) and finally Pusen 7.5F (255 lx). The same ranking was found at 50% brightness setting, with the highest ureteroscope illuminance value 34 times that of the scope with lowest illuminance. Most scopes had maximum illuminance off center, with skewness. Three scopes had two light sources, with one light source for all other scopes. Inter-scope comparisons revealed significant differences of color temperature (ANOVA p < 0.001). CONCLUSION: The study demonstrates the presence of inhomogeneous light spread as well as large differences in illumination properties of ureteroscopes, possibly impacting on the performance of individual scopes in vivo. Additionally, the study suggests that future studies on illumination characteristics of flexible ureteroscopes should ideally be done in saline, and no longer in air.

Fluid dynamics within renal cavities during endoscopic stone surgery: does the position of the flexible ureteroscope and ureteral access sheath affect the outflow rate?

PURPOSE: To evaluate the impact of ureteroscope position within renal cavities as well as different locations of the tip of the ureteral access sheath (UAS) on fluid dynamics during retrograde intrarenal surgery (RIRS). MATERIALS AND METHODS: A prospective observational clinical study was performed. Measurements with a flexible ureteroscope placed in the upper, middle and lower calyces were obtained with the tip of the UAS placed either 2 cm below the pyelo-ureteric junction (PUJ), or at the level of the iliac crest. RESULTS: 74 patients were included. The outflow rates from the middle and upper calyxes were statistically significantly higher compared to the lower calyx, both with the UAS close to the pyelo-ureteric junction and at the iliac crest. When the UAS was withdrawn and positioned at the level of the iliac crest, a significant decrease in outflow rates from the upper (40.1 ± 4.3 ml/min vs 35.8 ± 4.1 ml/min) and middle calyces (40.6 ± 4.0 ml/min vs 36.8 ± 4.6 ml/min) and an increase in the outflow from the lower calyx (28.5 ± 3.3 ml/min vs 33.7 ± 5.7 ml/min) were noted. CONCLUSIONS: Our study showed that higher fluid outflow rates are observed from upper and middle calyces compared to lower calyx. This was true when the UAS was positioned 2 cm below the PUJ and at the iliac crest. Significant worsening of fluid dynamics from upper and middle calyces was observed when the UAS was placed distally at the level of the iliac crest. While the difference was statistically significant, the absolute change was not significant. In contrast, for lower calyces, a statistically significant improvement was documented.

Percutaneous nephrolithotomy or flexible ureteral lithotripsy, which one is better for patients with upper ureteral calculi of 1.5-2.0 cm in diameter.

PURPOSE: First research to evaluate the clinical efficacy and safety of flexible ureteral lithotripsy (FURSL) and percutaneous nephrolithotomy (PCNL) in the treatment of the upper ureteral stone is between 1.5 cm and 2.0 cm in diameter since there is no consensus with such ureteral stone yet. METHODS: From December 2018 to October 2022, 104 patients with calculi in the upper ureter received percutaneous nephrolithotomy (PCNL)or flexible ureteroscopic lithotripsy (FURSL) in our institution. The clinical data of the patients in the two groups were retrospectively searched. Stone removal rate, operation time, blood loss, postoperative pain score, postoperative inflammatory factor, postoperative complication rates and ureteral obstruction three months after the operation were compared between the two groups. RESULTS: A total of 104 patients were included in the study. The stone clearance rate and the secondary surgery rate were 88.89% and 7.41% in the FURSL group, the figures were 97.96% and 2.0% in the PCNL group (p = 0.067, 0.497). Regarding ureteral obstruction three months after the operation, there were 2 patients in FURSL group and 0 patients in PCNL group(p = 0.497).Compared to patients in FURSL group, patients in the PCNL group had shorter operation time(PCNL 71.81 ± 18.94 min vs. FURSL 86.80 ± 22.49 min, p = 0.0004), fewer complications(PCNL 20.37% vs. FURSL 6.12%), and lower postoperative inflammatory factor(p = 0.0004), yet they got more hemoglobin drop (PCNL 13.14 ± 9.81 g/L vs. FURSL 4.77 ± 3.55 g/L, p < 0.0001), higher postoperative pain scores(p = 0.0017) in the first three postoperative days and longer hospital stay (PCNL 4.96 ± 1.21 days vs. FURSL 3.60 ± 0.83 days). CONCLUSION: Both FURSL and PCNL were effective methods for treating upper ureteral stones of 1.5-2.0 cm in diameter given the extremely high stone clearance rate and a very low secondary surgery rate, as long as rare ureteral obstruction in medium-long term observation. Additionally, FURSL can effectively reduce surgical bleeding, postoperative pain, and hospital stay, while PCNL can decrease operation time, the risk of infection, and complications. Therefore, doctors could select suitable surgical treatment for those patients depending on their different clinical situations based on these findings.

Effect of nephrostomy sheath size on renal pelvic pressure during endoscopic combined intrarenal surgery: artificial kidney model study.

BACKGROUND: This study aimed to evaluate the intrarenal pelvic pressure in endoscopic combined intrarenal surgery using an artificial kidney model. METHODS: An artificial kidney model was created using the Urovac evacuator™. Four sizes of nephrostomy sheaths (MIP-L: 25/26 Fr, MIP-M: 16.5/17.5 Fr, MIP-S: 11/12 Fr, MIP-XS: 8.5/9.5 Fr) and two sizes of ureteral access sheaths (12/14 Fr and 10/12 Fr) were installed into the model. For each combination of nephrostomy and ureteral access sheath, renal pelvic pressure was measured with and without insertion of the retrograde flexible ureteroscope. Irrigation from the nephroscope was adjusted to 40-160 mmHg using an automatic irrigation device, and the irrigation of the ureteroscope was by spontaneous dripping at 80 cmH2O. Conditions were measured six times, and the renal pelvic pressure was compared in different conditions. RESULTS: Without ureteroscope insertion through the ureteral access sheath, the renal pelvic pressure never exceeded 30 mmHg. Meanwhile, when the ureteroscope was inserted, the renal pelvic pressure increased as the nephrostomy sheath and ureteral access sheath became narrower and as the irrigation pressure increased. Intrarenal pelvic pressure exceeded 30 mmHg when the irrigation pressure was increased in 12/14 Fr ureteral access sheath when MIP-XS was used, and in 10/12 Fr ureteral access sheath when MIP-XS and MIP-S were used. CONCLUSIONS: The use of a thin nephrostomy sheath in endoscopic combined intrarenal surgery can lead to increased intrarenal pelvic pressure. Although our results are from an artificial kidney model, special care is suggested to be required when using a retrograde flexible ureteroscope simultaneously in treatment of patients.

Play it safe: renal function after bilateral flexible ureteroscopy for kidney stones.

PURPOSE: We searched for perioperative renal function deterioration risk factors in patients that underwent bilateral flexible ureteroscopy (fURS) for kidney stones. METHODS: From August 2016 to February 2020, symptomatic patients > 18 years old with bilateral kidney stones up to 20 mm in each side were prospectively studied. Serum creatinine samples were collected on admission to surgery, immediate postoperative (IPO), on POD 3, 10, and 30. Estimated glomerular filtration rate (eGFR) was calculated using Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) without a race coefficient. RESULTS: Thirty patients underwent bilateral fURS. Comparing to preoperative eGFR, median IPO and POD3 eGFR (p < 0.001) were significantly lower, and POD10 (p = 0.092) and POD30 (p = 0.648) were similar to preoperative eGFR. During follow-up, 22/30 (73.3%), 14/30 (46.7%), and 7/30 (23.3%) of the patients presented a decrease > 10% eGFR, > 20% eGFR, and > 30% eGFR, respectively. Multivariate analysis demonstrated that lower preoperative eGFR is a risk factor for eGFR < 60 mL/min/1.73 m2, p = 0.019 [1.021-1.263; 1.136]; ASA > 1 is a risk factor for decrease of eGFR > 10%, p = 0.028 [1.25-51.13; 8.00]; longer operative time is a risk factor for decrease of eGFR > 20%, p = 0.042 [1.00-1.05; 1.028]; and operative time ≥ 120 min is a risk factor for decrease of eGFR > 30%, p = 0.026 [0.016-0.773; 0.113]. CONCLUSIONS: Renal function suffers a reversible decrease after bilateral fURS. Our study suggests that adequate selection of patients and maintaining operative time < 120 min are relevant factors in preventing acute renal function deterioration following bilateral fURS.

Illumination matters Part III: Impact of light obstruction on illuminance from flexible ureteroscopes - a comparative PEARLS analysis.

PURPOSE: Artifacts from poor ureteroscopes' light design with shadowing and dark areas in the field of view have been reported. The aim was to quantify effects of light obstruction in a kidney calyx model. METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU Wiscope using an enclosed 3D-printed pink in vitro kidney calyx model submerged in saline, where the field of light was intentionally partially obstructed alternatively at 12, 3, 6, and 9 o'clock. A color spectrometer was used for illuminance measurements at a 45° opening position in the background of the model. RESULTS: Overall and mean background illuminance for each obstructive situation were significantly different between scopes for both 50% and 100% brightness settings (ANOVA p < 0.001). At 50% brightness setting, almost all scopes had their highest and lowest background illuminance with the 6 o'clock and 3 o'clock obstructive situation, respectively. At 100% brightness setting, these became 6 o'clock and 12 o'clock obstructive situations. Considering each obstructive situation individually, the Flex-Xc was consistently the scope with highest background illuminance and the Pusen 7.5F the lowest. Background illuminance for each obstructive situation varied significantly for each scope individually, with the greatest range of variability for Pusen 7.5F and V3. CONCLUSIONS: Illuminance performance of ureteroscopes within an obstructed calyx model differ significantly for various obstructive situations. Urologists should be aware of this to help guide their choice of ureteroscope.

Initial Experience and Clinical Assessment of the Karl Storz FLEX-XC1 Single-Use Flexible Ureteroscope.

INTRODUCTION: The Karl Storz FLEX-XC1 is a novel single-use flexible ureteroscope that uses the same videographics platform as its reusable digital counterpart. We evaluated the technical performance of the FLEX-XC1 in its initial clinical use. METHODS: We reviewed a series of consecutive ureteroscopy procedures performed by 2 endourologists using the FLEX-XC1 for indications for which we typically use a single-use device: total stone burden > 15 mm or > 10 mm in the lower pole, anticipated case duration > 60 minutes, bilateral procedure, or upper tract urothelial cancer procedures. We assessed device tip deflection, intraoperative mechanical failure, and clinical outcomes for each case. Surgeons rated visual clarity, image quality, and maneuverability on a 1 to 5 Likert scale. RESULTS: Of 29 procedures using FLEX-XC1, 27 (93%) were successfully completed. Preoperative upward deflection was < 270° in 6 (21%) cases, and downward deflection was < 270° in 9 (31%) cases. Three types of intraoperative malfunctions occurred: rotational twisting of deflectable tip (4 cases, 13%), device not advancing through distal ureter (1 case, 3%), and working channel not accommodating a 365-µm laser (1 case, 3%). Visual clarity, image quality, and maneuverability were rated as 5 "very good" or 4 "good" in 100%, 100%, and 97% of cases, respectively. No device-specific or general 30-day complications were observed. CONCLUSIONS: The FLEX-XC1 showed comparable image quality and maneuverability to reusable digital devices. We observed incomplete deflection in up to 31% of cases and mechanical failure in 2 cases. The FLEX-XC1 may be advantageous in prolonged cases where maintaining visual clarity is paramount.

Efficacy of flexible ureterorenoscopy with holmium laser in the management of calyceal diverticular calculi.

The purpose of this study was to evaluate the efficacy and safety of flexible ureteroscopy with holmium laser lithotripsy in the management of calyceal diverticular calculi. In this study, we retrospectively analyzed the clinical data of 27 patients with calyceal diverticular calculi admitted to the Department of Urology of the Zigong First People's Hospital from May 2018 to May 2021. Intraoperatively, the diverticular neck was found in all 27 patients, but flexible ureterorenoscopy lithotripsy was not performed in 2 cases because of the slender diverticular neck, and the success rate of the operation was 92.6%. Of the 25 patients with successful lithotripsy, the mean operative time was 76.9 ± 35.5 (43-200) min. There were no serious intraoperative complications such as ureteral perforation, mucosal avulsion, or hemorrhage. Postoperative minor complications (Clavien classification I-II) occurred in 4 (16%) patients. The mean hospital stay was 4.4 ± 1.7 (3-12) days. The stone-free rate was 80% at the 1-month postoperative follow-up. After the second-stage treatment, the stone-free rate was 88%. In 22 cases with complete stone clearance, no stone recurrence was observed at 5.3 ± 2.6 (3-12) months follow-up. This retrospective study demonstrated that flexible ureterorenoscopy with holmium laser is a safe and effective choice for the treatment of calyceal diverticular calculi, because it utilizes the natural lumen of the human body and has the advantages of less trauma, fewer complications, and a higher stone-free rate.

The optimal ratio of endoscope-sheath diameter with negative-pressure ureteral access sheath: an in vitro research.

PURPOSE: To maintain safe intrarenal pelvic pressure (IPP), the combination of flexible ureteroscope (fURS) and traditional ureteral access sheath (T-UAS) should maintain a basic rule that is the ratio of endoscope-sheath diameter (RESD) ≤ 0.75. However, the negative-pressure ureteral access sheath (NP-UAS) may break the rule of negative pressure suction. This study aimed to examine the effect of NP-UAS on IPP and flow rate (FR) with varying RESD. METHODS: In a 3D-printed renal model, flexible ureteroscopy lithotripsy (fURL) was replicated. Six sizes of fURS paired with 12Fr T-UAS and NP-UAS resulted in six distinct RESDs of 0.63, 0.78, 0.87, 0.89, 0.90, and 0.91. While the irrigation pressure (IRP) was set between 100 and 800 cmH2O and the sucking pressure (SP) was set between 0 and 800 cmH2O, the IPP and FR were measured in each RESD. RESULTS: NP-UASs can reduce the IPP and increase the FR at the same RESD compared to T-UASs. The IPP decreased with increasing SP with NP-UAS. When RESD ≤ 0.78, T-UAS and NP-UAS can maintain IPP < 40 cmH2O in most circumstances. When RESD = 0.87, it is challenging for T-UAS to sustain IPP < 40 cmH2O; however, NP-UAS can do so. When RESD ≥ 0.89, it is difficult to maintain an IPP < 40 cmH2O even with NP-UAS. CONCLUSION: NP-UAS can decrease IPP and increase FR compared with T-UAS. To maintain a safe IPP, it is recommended that RESD < 0.85 when utilizing NP-UAS.