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Introduction: Several complications of retrograde intrarenal surgery have been attributed to inadvertent increases in intrarenal pressure. We recently described the development of an innovative isoprenaline-eluting guidewire (IsoWire). The objective of this study was to investigate the impact of this IsoWire on the intrarenal pressure and evaluate its safety. Materials and Methods: This study was performed in 17 renal units using a porcine model. As controls, the intrarenal pressure, heart rate, and mean arterial pressure were measured for a duration of six minutes with a standard guidewire placed in the renal pelvis. For the experiment, the conventional guidewire was substituted with the IsoWire and the same parameters were measured. Blood samples were taken at one-minute intervals to measure plasma isoprenaline levels. This procedure was repeated on the opposite side. Results: The mean intrarenal pressure reduction was 29% (95% CI: 13%–53%). The mean isoprenaline effect time was 174 seconds. No changes in heart rate (p =.908) or mean arterial pressure (p =.749) were recorded after IsoWire insertion. Plasma isoprenaline levels were below the quantitation threshold. Isoprenaline concentrations in the plasma were below the quantification threshold. Ureteroscopy revealed no ureteral lesions. Conclusions: The IsoWire demonstrated a safe and effective reduction of intrarenal pressure. Additional research is necessary to determine whether ureteral smooth muscle relaxation generated by isoprenaline facilitates easier insertion of a ureteral access sheath, decreases the incidence of ureteral access sheath related ureteral lesions, or even encourage the practice of sheathless retrograde intrarenal surgery. [ABSTRACT FROM AUTHOR]

Aim: To describe the operative technique and outcome of one trocar-assisted retroperitoneoscopic ureteroureterostomy (OTAU) in 40 cases of complete ureteral duplication in children. Patients and Methods: From September 2016 to December 2020, 40 patients (12 male and 28 female) less than 10 years of age underwent OTAU. A transverse skin incision of 12 mm in length was created approximately 1 cm above the iliac crest. Muscle was spared and retracted with stay sutures to expose the retroperitoneal space. Subsequently, a balloon trocar was then inserted, and pneumoperitoneum was achieved. A 10 mm operating laparoscope (Stema, Germany) with a Maryland was used to dissect and isolate the ureters from surrounding tissues. The ureters were then exteriorized and end-to-side ureteroureterostomy was performed using Polydioxanone (PDS) 6/0 running sutures. Patient's demographic, operative, and follow-up data were collected prospectively. Results: The mean age of patients was 25.2 months (range: 1–105 months). The mean operating time was 81.9 ± 11.3 minutes. There were no intraoperative conversions or complications. After a median follow-up time of 47.5 months, the differential renal function of the pathological upper pole moiety (UPM) was preserved in all patients. Ultrasound revealed a significant reduction in UPM's renal pelvis anterior–posterior diameter from 19.6 ± 9.1 mm preoperatively to 11.1 ± 6.7 mm postoperatively (p < 0.05), accompanied by a reduction in ureter's diameter from 10.8 ± 4.4 mm to 4.8 ± 1.2 mm (p < 0.05). Overall, all 32 patients with preoperative symptoms experienced complete symptom resolution. Conclusion: OTAU is a safe and feasible approach that yields excellent outcomes for complete ureteral duplication. [ABSTRACT FROM AUTHOR]

Introduction: Retrograde intrarenal surgery (RIRS) is associated with complications, many of which are related to the intrarenal pressure (IRP). We aim to describe the design of a novel isoprenaline-eluting guidewire ("IsoWire") and present the results from the first in vitro release studies and the first animal studies showing its effect on IRP. Materials and Methods: The IsoWire comprises a Nitinol core surrounded by a stainless-steel wire wound into a tight coil. The grooves created by this coil provided a reservoir for adding a hydrogel coating into which isoprenaline, a beta-agonist, was loaded. Animal studies were performed using a porcine model. For the control, IRP, heart rate (HR), and mean arterial pressure (MAP) were measured continuously for 6 minutes with a standard guidewire in place. For the experiment, the standard hydrophilic guidewire was removed, the IsoWire was inserted into the renal pelvis, and the same parameters were measured. Results:In vitro analysis of the isoprenaline release profile showed that most (63.9 ± 5.9%) of the loaded drug mass was released in the 1st minute, and almost all of the drug was released in the first 4 minutes exponentially. Porcine studies showed a 25.1% reduction in IRP in the IsoWire that released 10 μg in the 1st minute; however, there was a marked increase in HR. The average percentage reduction in IRP was 8.95% and 21.3% in the IsoWire that released 5 and 7.5 μg of isoprenaline, respectively, with no changes in HR or MAP. Conclusions: The IsoWire, which releases 5 and 7.5 μg of isoprenaline in the 1st minute, appears to be safe and effective in reducing the IRP. Further studies are needed to establish whether the isoprenaline-induced ureteral relaxation will render easier insertion of a ureteral access sheath, reduce IRP during sheathless RIRS, or even promote the practice of sheathless RIRS. [ABSTRACT FROM AUTHOR]

Objective: To assess the outcomes of redo laparoscopic pyeloplasty (RLP) in pediatric patients with recurrent ureteropelvic junction obstruction (UPJO) in contrast to redo open pyeloplasty (ROP). In addition, evaluate the feasibility and efficacy of RLP as a treatment modality for recurrent UPJO in children. Materials and Methods: The data of 44 patients from March 2012 to March 2022, who underwent redo pyeloplasty, were retrospectively reviewed. In Group RLP, the children underwent RLP, whereas ROP was attempted in Group ROP. Demographics, clinical manifestations, surgical duration, hospitalization duration, complication rates, and treatment success were examined within the respective groups. Moreover, preoperative and postoperative measurements of anterior–posterior diameter of the renal pelvis (APD), preoperative assessment of differential renal function (DRF), and the percentage of improvement in DRF (PI-DRF) were subject to analysis. Results: The study included 28 patients who underwent RLP (Group RLP), and 16 patients who underwent ROP (Group ROP). In all cases, the Anderson–Hynes technique was employed. There was no significant difference between the two groups regarding age, body mass index, gender distribution, affected side, preoperative APD, postoperative APD, and preoperative DRF. In comparison to Group ROP, Group RLP exhibited a shorter hospitalization duration, a longer surgical procedure duration, and a higher percentage improvement in PI-DRF. The median follow-up period for Group RLP was 25 months, whereas it was 25.5 months for Group ROP. Notably, the success rates were similar between the two groups, with a success rate of 89.2% in RLP and 87.5% in ROP (p = 0.634). Conclusion: RLP has a comparable success rate to ROP and is a safe, effective, and feasible procedure for the treatment of failed pyeloplasty in children. [ABSTRACT FROM AUTHOR]

Objective: The primary aim of the study was to explore intrarenal temperatures (IRTs) during flexible ureteroscopic laser lithotripsy (FURSL). The secondary aim was to investigate the correlation between temperatures and renal pelvis anteroposterior diameter (APD). Materials and Methods: From February 2023 to June 2023, 10 patients with an indwelling nephrostomy tube (NT) undergoing FURSL were enrolled in the study. Sheathless FURSL was performed using gravitational irrigation (23°C) at 60 cm. A sterile K-type thermocouple was inserted through the NT. Temperatures were recorded for 120 seconds with continuous laser activation and for another 60 seconds after deactivation. Thulium fiber laser delivered energy using a 150 μm fiber and incremental power settings of 5, 10, 20, and 30 W. The laser was deactivated whenever the IRT reached 43°C. Results: IRT correlated directly to power settings. Each time the power settings were increased, the temperature rose significantly. The increase in average peak temperature was 2.6°C between 5 and 10 W (p < 0.001), 3.4°C between 10 and 20 W (p < 0.001), and 2.5°C between 20 and 30 W (p < 0.001). Temperatures reached 43°C in three patients applying 20 W and in eight patients applying 30 W. The shortest activation-time until threshold was 12 and 28 seconds with 30 and 20 W settings, respectively. When reaching 43°C, temperatures remained above this threshold for an additional 29 seconds on average. There was a significant correlation between IRT and renal APD. For example, when 10 W was applied in the setting of APD ≤20 mm, the recorded temperature was on average 2.3°C higher compared with APD >20 mm, with the same power settings applied, p < 0.001. Conclusion: During FURSL, IRT correlates directly with power settings and is inversely correlated with renal pelvic APD. Using a sheathless approach, power settings ≥20 W should arguably be avoided, especially in the context of a nondilated renal pelvis. ClinicalTrials: The study was registered on ClinicalTrials.gov (NCT05677425). [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to assess the efficacy and safety of laparoscopic surgery in the treatment of pediatric ureteral fibroepithelial polyp (FEP) patients. Our hypothesis is that laparoscopic surgery can effectively treat FEPs while minimizing patient discomfort and complications. Our research aims to evaluate the clinical outcomes of the surgery, including postoperative symptom relief, improvement in kidney function, and risk of postoperative complications. Methods: The clinical records of 34 patients who underwent ureteral polyp surgery at the Department of Urology at Anhui Provincial Children's Hospital between May 2014 and February 2023 were retrospectively analyzed. All patients underwent laparoscopic surgery. Among the 34 pediatric patients, there were 31 males and 3 females, with 2 on the right side and 32 on the left side. Of these cases, 24 polyps were located at the ureteropelvic junction, while seven were found in the upper segment of the ureter and three in its middle segment. Patients' ages ranged from 4 years and 3 months to 15 years, with a median age of 8 years and 6 months. All children presented with varying degrees of hydronephrosis, and preoperative clinical symptoms included ipsilateral flank or abdominal pain, hematuria, and other discomfort. Preoperative examinations mainly comprised ultrasound, intravenous pyelography, CT, or magnetic resonance urography imaging studies, as well as diuretic renography. All pediatric patients underwent laparoscopic excision of the polyp segment of the ureter, followed by renal pelvis ureteroplasty or ureter-to-ureter anastomosis. Results: All patients underwent surgery without conversion to open surgery. The surgical duration ranged from 72 to 313 minutes, with an average of 179.5 minutes. The average intraoperative blood loss was 14 mL. Postoperatively, one patient experienced leakage at the anastomotic site; however, no other significant complications occurred during or after the procedure. Postoperative histopathology confirmed the presence of FEPs in the ureter for all cases. All patients experienced a favorable postoperative recovery, with hospitalization periods ranging from 3 to 16 days and an average stay of 8.6 days. A Double-J stent was inserted in all patients for a duration of 1 to 2 months after surgery, and upon removal, follow-up color Doppler ultrasound revealed reduced hydronephrosis within 1 to 3 months. Follow-up examinations were conducted at intervals ranging from 3 to 108 months postsurgery, with an average follow-up time of 42.2 months, during which no recurrence of ureteral polyps or symptoms such as pain and hematuria was observed. Conclusions: The findings of this study demonstrate that laparoscopic excision of the polyp segment of the ureter, renal pelvis ureteroplasty, and ureter-to-ureter anastomosis represent safe and effective treatment modalities for pediatric FEPs in the ureters. This technique offers several advantages, including minimal invasiveness, rapid recovery, and definitive therapeutic efficacy, which effectively alleviate clinical symptoms and improve hydronephrosis. [ABSTRACT FROM AUTHOR]

Introduction: Electromotive Drug Administration (EMDA) amplifies drug delivery deep into targeted tissues. We tested, for the first time, the ability of EMDA to deliver methylene blue into the urothelium of the renal pelvis. Materials and Methods: In an anesthetized female pig, both proximal ureters were transected two inches distal to the ureteropelvic junction. An 8F dual lumen catheter and a 5F fenestrated catheter with an indwelling silver wire were inserted into both renal pelvises following which methylene blue (0.1%) was infused at a rate of 5 mL/min for 20 minutes. In one pelvis, a 4 mA positive pulsed electrical current was applied to the silver wire. Results: In contrast to the control pelvis, the EMDA side macroscopically exhibited dense homogeneous staining; microscopy revealed penetration of methylene blue into the urothelium/lamina propria. Conclusion: In the porcine renal pelvis, application of EMDA increased the penetration of a charged molecule into the urothelium/lamina propria. [ABSTRACT FROM AUTHOR]

Introduction: Intrarenal pressure is emerging as an important monitoring parameter during flexible ureteroscopy (fURS). We measure how intraoperative conditions affect intrarenal pressure using a novel pressure sensing ureteroscope. Methods: The LithoVue Elite (LVE) single-use digital flexible ureteroscope (Boston Scientific) is the first commercial ureteroscope that senses pressure at its tip. LVE was used in a porcine model to measure intrarenal pressure with and without a ureteral access sheath (UAS) with various sizes and placement locations, irrigation methods, and working channel accessories. LVE pressure accuracy was measured in a bench model. This abstract shows the least-square means from multiway analysis of variances used for analysis. Results: Intrarenal pressures were the highest without a UAS (64 mm Hg), followed by the 11/13 UAS (51 mm Hg) and the 12/14 and 13/15, which were not statistically different (39–40 mm Hg). The pressures were highest with UASs placed at the ureteropelvic junction (61 mm Hg), and lowest if placed in the renal pelvis (24 mm Hg). Irrigation methods showed the highest pressures with syringe (57 mm Hg), while irrigation bags (pressurized at 150–300 mm Hg) produced 43 to 46 mm Hg and 25 mm Hg when applied with 80 cm of gravity. Placing a 200 μm laser fiber reduced pressures from 44 to 41 mm Hg. Finally, the bench model showed that LVE was 96% accurate up to 300 mm Hg. Conclusion: Intrarenal pressure significantly varied based on UAS sizes, placement, and irrigation methods. Accordingly, fURS with LVE is poised to be an invaluable tool for clinical decision-making and future studies of intrarenal pressure. [ABSTRACT FROM AUTHOR]

Objective: To investigate the efficacy of ureteral tailoring with or without ureteral bladder reimplantation in the treatment of primary megaureter (MGU) in children by transvesicoscopic ureteral reimplantation. Methods: Clinical data from 21 children with primary MGU who were treated with pneumo-bladder ureterovesical reimplantation in Anhui Children's Hospital from January 2019 to August 2022 were retrospectively analyzed. Thereafter, children were divided into two groups according to whether intraoperative ureteral tailoring was performed, including 9 in the trimmed group and 12 in the nontrimmed group. In the meantime, there were 16 males and 5 females, with the age of 4.7 ± 2.12 years. Furthermore, there were 17 obstructive MGU cases, 2 reflux MGU cases, and 2 obstructive with reflux MGU cases, with 16 cases on the left side (including 1 case of Y-shaped ureter in the left duplicated kidney), whereas 5 on the right side. All children underwent transvesicoscopic ureteral reimplantation (the Cohen procedure). Thereafter, changes in operation time, duration of retained catheterization, hematuria time, renal pelvis and ureteral dilatation, and tortuosity between two groups were compared 3 months after Double-J tube removal. Results: All children were effectively treated with transvesicoscopic ureteral reimplantation, the operation time (p = 0.02, p < 0.05), postoperative hematuria time (p = 0.00, p < 0.05), and retained urinary catheter time (p = 0.00, p < 0.05) were shorter in the nontrimmed group, and the mean postoperative follow-up time was 27.6 (3–22) months. Moreover, the postoperative anteroposterior diameters of the affected renal pelvis in both groups were 0.31 ± 0.39 cm and 0.27 ± 0.29 cm, respectively, whereas the postoperative maximum ureteral diameters were 0.33 ± 0.31 cm and 0.27 ± 0.36 cm, separately, which were significantly reduced compared with the preoperative counterparts. All children recovered well, with no postoperative complications. Conclusion: Whether intraoperative ureteral clipping is performed or not does not significantly affect the outcome of transvesicoscopic laparoscopic ureteral bladder reimplantation for primary MGU in children. Both groups of children improved with satisfactory surgical results, but the nontrimmed group has shorter operation time, simpler operation, and less trauma. [ABSTRACT FROM AUTHOR]

Introduction/Background: There are increasing reports of serious complications related to the air pyelography technique, which raise concerns about the safety of room air (RA) injection into the renal collecting system. Carbon dioxide (CO2) is much more soluble in blood than nitrogen and oxygen and thus considerably less likely to cause gas emboli. Iodinated contrast medium (ICM) is expensive, and supplies may not be as reliable as previously assumed. CO2 pyelography (CO2-P) techniques using standard fluoroscopy and digital subtraction fluoroscopy (CO2 digital subtraction pyelography [CO2-DSP]) are described. Materials and Methods: During the endourologic stone cases, 15 to 20 mL of CO2 gas was typically injected into the renal pelvis through a catheter or sheath. Imaging was usually obtained with endovascular CO2 digital subtraction angiography settings using either a traditional fluoroscopy system (TFS) or robotic arm multiplanar fluoroscopy system (RMPFS) (Artis Zeego Care+Clear®; Siemens). Results: CO2-P was performed in 22 endoscopic stone treatment cases between March 2021 and August 2022, primarily using digital subtraction settings in 20 cases. CO2-DSP overall provided higher quality images of the renal pelvis and collecting system than CO2-P, but with a relatively higher radiation dose. Following a quality intervention, fluoroscopy doses for CO2-DSP cases were decreased by 81% overall. The use of CO2-P avoided fluoroscopic or intraoperative CT (ICT) artifacts seen with intraluminal ICM. Conclusions: CO2-P allows the urologist to obtain imaging of the renal collecting system without ICM and with much lower risk of air embolism compared with RA pyelography. CO2 is a nearly cost-free alternative to ICM. Because CO2 is widely available and the technique is easy to perform, we propose that CO2-P should be favored over traditional air pyelography to improve patient safety. [ABSTRACT FROM AUTHOR]

Background: Proper control of irrigation flowrate during ureteroscopy is important to manage thermal and pressure risks. This task is challenging because flowrate is not directly measured by commercially available ureteroscopic or fluid management systems. However, flowrate can be calculated using a hydrodynamic relationship based on measurable values during ureteroscopy. Objectives of this in vitro study were to (1) calculate inflow resistance for different working channel conditions and then using these values and (2) calculate irrigation flowrate and determine its accuracy across a range of renal pelvis pressures. Materials and Methods: A 16 L container was filled with deionized water and connected by irrigation tubing to a 9.6F single-use ureteroscope. Inflow resistance was determined by plotting flowrate (mass of fluid collected from ureteroscope tip in 60 seconds) vs irrigation pressure (range 0–200 cmH2O). Next, the tip of the ureteroscope was inserted into the renal pelvis of a silicone kidney–ureter model and renal pelvis pressure was measured. In conjunction with the previously determined inflow resistance and known irrigation pressure values, flowrate was calculated and compared with experimentally measured values. All trials were performed in triplicate for working channel conditions: empty, 200 μm laser fiber, 365 μm laser fiber, and 1.9F stone basket. Results: Flowrate was linearly dependent on irrigation pressure for each working channel condition. Inflow resistance was determined to be 5.0 cmH2O/(mL/min) with the 200 μm laser fiber in the working channel and calculated flowrates were within 1 mL/min of measured flowrates. Similar results were seen with a 365 μm laser fiber, and 1.9F basket. Conclusions: Utilizing renal pelvis pressure measurements, flowrate was accurately calculated across a range of working channel conditions and irrigation pressures. Incorporation of this methodology into future ureteroscopic systems that measure intrarenal pressure could provide a real-time readout of flowrate for the urologist and thereby enhance safety and efficiency of laser lithotripsy. [ABSTRACT FROM AUTHOR]

Percutaneous nephrolithotomy (PCNL) has evolved many a fold and was originally described in supine position by Valdivia et al. In this position, the direction of the tract is posterior and thus preserves a low pressure in the renal pelvis, and thereby reduces the risk of fluid absorption and allows spontaneous clearance/washout of fragments by gravity-directed flow of fluid. Supine PCNL is feasible in most situations. It is an important tool for patients who have musculoskeletal abnormalities precluding prone positioning. It gives the surgeon a simultaneous opportunity to do flexible ureteroscopy. Mobility of the kidney may make the puncture difficult. Suctioning of the dust using the suction sheath in supine PCNL makes the procedure more effective. [ABSTRACT FROM AUTHOR]

Objectives: To compare the safety and effectiveness of a novel flexible vacuum-assisted ureteral access sheath (FV-UAS) and traditional ureteral access sheath (UAS) in simulating retrograde intrarenal surgery (RIRS). Materials and Methods: A manometric model was established in porcine kidneys to observe the change in intrarenal pressure (IRP) in the FV-UAS and traditional UAS groups at different irrigation fluid velocities of 30, 50, 80, and 100 mL/min. Establish a kidney stone model (with 0.2 g, dry, ≤5 mm stones) to simulate RIRS. A total of 20 porcine kidneys were randomly numbered from 1 to 20 (FV-UAS group, 1 − 10; traditional UAS group, 11 − 20). The stone volume clearance rate and operation time were compared between the two groups. (" S t o n e v o l u m e c l e a r a n c e r a t e = 1 − R e s i d u a l s t o n e v o l u m e P r e o p e r a t i v e s t o n e v o l u m e × 1 0 0 % "). Stone volume was obtained by CT pre- and postoperatively. Results: FV-UAS can follow flexible ureteroscopy (f-URS) to cross the ureteropelvic junction (UPJ) and into the renal pelvis and calices. FV-UAS can actively make IRP <10 cmH2O by adjusting the negative values at different irrigation fluid velocities. The mean residual stone volume of the FV-UAS vs traditional UAS groups was 33.7 vs 92.5 mm3 (p = 0.017). The mean stone volume clearance rates of the FV-UAS vs traditional UAS groups were 98.5% and 95.9%, respectively (p = 0.017). Seven cases achieved complete stone-free status in the FV-UAS group. All patients had residual fragments postoperatively in the traditional UAS group. Conclusions: FV-UAS can follow f-URS to cross the UPJ and into the renal pelvis and calices, avoiding the interference of UPJ in controlling IRP. FV-UAS can actively control the IRP to be reduced to the desired range by adjusting the negative value under any irrigation fluid velocity. FV-UAS close to the stone can achieve complete stone-free status in RIRS. [ABSTRACT FROM AUTHOR]

Background and purposeUreteropelvic junction obstruction is a common urologic condition that accounts for approximately $12 million in inpatient spending annually. Few studies have assessed the costs related to treatment. We sought to examine the cost of care for patients treated for ureteropelvic junction obstruction.Patients and methodsWe used the MarketScan® database to identify adults from 18 to 64 years old treated with minimally invasive pyeloplasty, open pyeloplasty, and endopyelotomy for ureteropelvic junction obstruction between 2002 and 2010. Our primary outcome was total expenditures related to the surgical episode, defined as the period from 30 days prior until 30 days after the index surgery. We fit a multinomial linear regression model to evaluate cost of the surgical episode, adjusting for age, gender, comorbidity, benefit plan type, and region of residence.ResultsWe identified 1251 endopyelotomies, 717 open pyeloplasties, and 1048 minimally invasive pyeloplasties. The adjusted mean costs were $16,379 for endopyelotomy, $22,421 for open pyeloplasty, and $22,843 for minimally invasive pyeloplasty (p

Background and purposeUreteropelvic junction obstruction is a common condition that can be treated with open pyeloplasty, minimally invasive pyeloplasty, and endopyelotomy. While all these treatments are effective, the extent to which they are used is unclear. We sought to examine the dissemination of these treatments.Patients and methodsUsing the MarketScan® database, we identified adults 18 to 64 years old who underwent treatment for ureteropelvic junction obstruction between 2002 and 2010. Our primary outcome was ureteropelvic junction obstruction treatment (i.e., open pyeloplasty, minimally invasive pyeloplasty, endopyelotomy). We fit a multilevel multinomial logistic regression model accounting for patients nested within providers to examine several factors associated with treatment.ResultsRates of minimally invasive pyeloplasty increased 10-fold, while rates of open pyeloplasty decreased by over 40%, and rates of endopyelotomy were relatively stable. Factors associated with receiving an open vs a minimally invasive pyeloplasty were largely similar. Compared with endopyelotomy, patients receiving minimally invasive pyeloplasty were less likely to be older (odds ratio [OR] 0.96; 95% confidence interval [CI], 0.95, 0.97) and live in the south (OR 0.52; 95% CI, 0.33, 0.81) and west regions (OR 0.57; 95% CI 0.33, 0.98) compared with the northeast and were more likely to live in metropolitan statistical areas (OR 1.52; 95% CI 1.08, 2.13).ConclusionsOver this 9-year period, the landscape of ureteropelvic junction obstruction treatment has changed dramatically. Further research is needed to understand why geographic factors were associated with receiving a minimally invasive pyeloplasty or an endopyelotomy.

Introduction: We sought to examine the intrarenal fluid and tissue temperature alterations during dusting and fragmentation with the thulium fiber laser (TFL) in an in vivo porcine kidney. Materials and Methods: In two female Yorkshire pigs, temperature was continuously measured within the upper, interpolar, and lower calices along with the renal pelvis using multipoint thermal sensor probes; another temperature probe was situated at the tip of the ureteroscope. Four experimental protocols were performed for each animal: dual lumen ureteroscope with both warmed (37°C) irrigation and room temperature (20°C–22°C) irrigation and single lumen ureteroscope with warmed and room temperature irrigation. Of note, in each pig, one kidney underwent ureteroscopy (URS) with a 14F ureteral access sheath (UAS) in place, whereas the other kidney had no UAS placed. A 200-μm TFL fiber was fired at three laser settings: (1) dusting at 0.5 J, 80 Hz (40 W) with continuous activation until 5 minutes expired or a temperature of 44°C was reached, (2) low-power fragmentation 1 J, 10 Hz, (10 W), and (3) high-power fragmentation at 1.5 J, 20 Hz (30 W). In all cases, the pulse width was 1 ms. For fragmentation, the laser was activated for 10 seconds with a 2-second intermission for a 1-minute period (five cycles). Results: In the absence of a UAS, in all but one circumstance, temperatures reached or exceeded 44°C at all laser settings with the use of either warm or room temperature irrigation fluid, regardless of the type of ureteroscope used. Of concern, temperatures recorded at the tip of the URS were 4°C to 22°C less than the temperatures recorded in the renal calices. In contrast, with a 14F UAS in place, six distinct groups had temperatures that did not exceed 44°C, specifically at low- and high-power fragmentation settings with room temperature irrigation for both sets of ureteroscopes and at dusting and low-power fragmentation settings with warm temperature irrigation solely for the single lumen ureteroscope. Temperatures recorded at the tip of the ureteroscope with the deployment of a UAS yielded temperature differences ranging from 17°C less to 19°C more than the renal calices. Conclusions: TFL is a novel laser technology for lithotripsy. In the absence of a UAS, high-power TFL fragmentation settings in particular may create temperatures within the collecting system that could result in urothelial tissue injury. Of note, peak temperatures recorded at the tip of the ureteroscope may misrepresent the actual intrarenal temperature during TFL laser lithotripsy. [ABSTRACT FROM AUTHOR]

Background: Comparative outcome studies investigating internal Double-J (DJ) and externalized stents have primarily been performed for open and laparoscopic pyeloplasty, with a paucity of literature surrounding outcomes in robot-assisted laparoscopic pyeloplasty (RALP). Furthermore, outcomes of a modified external stent inserted into the renal pelvis, termed cutaneous pyeloureteral (CPU) stent, remain unexamined. This study investigates outcomes of DJ and CPU stents as methods of trans-anastomotic drainage. Materials and Methods: A retrospective analysis identified pediatric patients who underwent RALP between December 2007 and January 2020 at a single tertiary center, where CPU stents were introduced in June 2012. Operative success was defined as improved or stable hydronephrosis without subsequent redo pyeloplasty. Secondary outcomes included stent reinsertion, anesthesia requirements, opioid administration, urinary tract infection (UTI), and bladder spasms. Results: A total of 103 pediatric RALP procedures were analyzed (DJ = 70, CPU = 33). Operative success (DJ = 95.7%, CPU = 100%, p = 0.55), Society for Fetal Urology (SFU) grade improvement, and length of stay were comparable. Accidental stent expulsion was only seen with CPU stents (9%; p = 0.03). Intracorporeal stent migration also occurred more frequently in CPU stents (DJ = 3%, CPU = 15%, p = 0.03). Stent reinsertion, when needed, used a DJ stent with rates of 4% and 9% for DJ and CPU stents, respectively (p = 0.38). DJ stents were removed at a later postoperative day (DJ = 45.2 ± 25.0, CPU = 8.3 ± 4.2; p < 0.001) with increased general anesthesia (DJ = 99%, CPU = 3%; p < 0.001) and intravenous (IV) opioid (DJ = 27%, CPU = 9%; p = 0.04) requirements. Finally, DJ stents had nonsignificant increased rates of UTI (DJ = 17%, CPU = 3%, p = 0.06) and bladder spasms necessitating postoperative medication (DJ = 26%, CPU = 9%, p = 0.07). Conclusions: DJ and CPU stents display equivalent success rates in pediatric RALP and similar stent reinsertion rates. Appreciable differences can inform stent selection, including higher general anesthesia requirements and IV opioid administration among DJ stents and a higher incidence of accidental stent expulsion among CPU stents. In addition, DJ stents were associated with nonsignificant increased rates of UTI and bladder spasm necessitating medication. [ABSTRACT FROM AUTHOR]

While percutaneous nephrolithotomy (PCNL) remains the treatment modality of choice for kidney stones larger than 2 cm, infectious complications are most common, ranging from 5% to 32%. We present here a novel technique for potentially improving collecting system sterility during PCNL and initial postoperative outcomes. Retrospective chart analysis data of our irrigation protocol were collected from our first 56 patients between February and July 2019. Traditional prone PCNL was performed in a standard manner using fluoroscopic guidance. Using a ureteral catheter that was placed cystoscopically, a renal pelvis urine culture was taken and subsequently 10 mL of betadine solution was instilled into the collecting system. Gentamicin in normal saline (80 mg/3 L) was utilized as the irrigant fluid for the first 6 L of irrigation. From this cohort, 57% patients were women and mean age was 60 ± 14 years. About 23% of patients were diabetic and 55% were hypertensive. Seventy percent of patients had stone burden >2 cm and no patients had stone burden <1 cm. Fifteen patients had positive urine cultures treated preoperatively, while four patients had contaminated cultures. All patients were treated with our antibiotic irrigation and betadine protocol regardless of preoperative cultures or antibiotics. Mean baseline creatinine level was 0.95 ± 0.41, with a mean change of 0.18 at postoperative day 1. Of the 15 (26%) of 56 patients with a systemic inflammatory response syndrome response (two of following four criteria: white blood cells <4 or >12; heart rate >90; hypothermia <96.8°F or hyperthermia >100.4°F; and respiratory rate >20), only six patients (11%) were febrile and two patients had positive blood cultures (3%). There were no adverse reactions to the betadine or antibiotic irrigation. We present here our initial experience of a new technique for renal pelvis sterilization and its safety and feasibility using intrarenal instillation of betadine and antibiotic irrigation. No Clinical Trial Registration number applicable. [ABSTRACT FROM AUTHOR]

Objective: It has been previously reported that warming irrigation fluid higher than body temperature may decrease ureteral spasm and thereby facilitate ureteroscopic access to the proximal ureter. Our objective was to examine the effects on ureteral peristalsis and ureteral diameter if the irrigant was warmed to just under the biological threshold for injury. Materials and Methods: Two female adult Yorkshire pigs were studied in this pilot study. In the first pig, a dilute mixture of contrast and irrigation fluid at 37°C and then at 43°C was instilled for 30 minutes into each renal pelvis through a ureteral catheter at 40 mm Hg. Retrograde pyelogram images were captured for each trial and the caliber of the ureter was measured using Vitrea® software. In the second pig, a lumbotomy was performed, and a magnetic sensor was placed on the extraluminal surface of the ureter to monitor ureteral peristalsis while repeating the aforedescribed regimen. Thirty minutes after the first regimen, the force exerted during placement of a 16F ureteral access sheath (UAS) was recorded at both temperatures using the University of California, Irvine Ureteral Force Sensor. Results: There was no statistically significant difference in ureteral caliber along the length of the ureter at 43°C (p = 0.87, p = 0.32, p = 0.66 for proximal, middle, and distal ureter, respectively). Indeed, there was an increase in peristalsis from baseline with fluid irrigation at 37°C and at 43°C (59% and 65%, respectively). There was no significant difference in the force exerted for UAS placement at either temperature. On histologic analysis, there were no significant changes in ureteral histology or luminal diameter. Conclusions: In a porcine model, warming irrigation fluid to just under the biological threshold for injury did not increase ureteral caliber, decrease ureteral peristalsis, or facilitate UAS placement. As such, during ureteroscopy, we continue to warm our irrigation fluid just to body temperature. [ABSTRACT FROM AUTHOR]

Objectives: The present study investigated the recent outcomes of chronic unilateral hematuria (CUH), focusing on the detailed distribution of bleeding points based on the anatomical classification of the pelvicaliceal system. Materials and Methods: We evaluated 75 CUH patients treated in the past decade. Bleeding points were recorded separately as five levels of minor calices (Top, Upper, Middle, Lower, and Bottom). Bleeding point detection, immediate success, and recurrence-free rates were assessed. Results: The median age was 47 (range: 13–81) years. Bleeding points were detected in 62 patients (83%), including at the Top calix in 24 patients (32%), the mid-calices (Upper, Middle, and Lower) in 20 patients (27%), and the Bottom calix in 18 patients (24%). As there are typically six total calices in the mid calices, the probability of bleeding per renal papilla was higher in the compound papillae at the Top and Bottom calices than in the simple papilla at the mid calices. The bleeding point detection rate was significantly higher in the 65 patients with confirmed unilateral gross hematuria than in the 10 patients without confirmation (88% vs 50%, p < 0.01). The immediate success rate was 97% (73/75), and only two patients (3%) needed a second ureteroscopy. Ultimately, all patients achieved the disappearance of gross hematuria, including 13 patients (17%) whose bleeding points were not identified by ureteroscopy. The recurrence-free rate was 100% at a median follow-up of 42 (3–139) months. Conclusions: Compound papillae are more likely to bleed than simple papillae. Therefore, we recommend evaluating the Top and Bottom calices carefully during the initial ureteroscopic observations. Since the patients with confirmed gross hematuria from the unilateral orifice had a higher rate of bleeding point detection than those without confirmation, it is important to perform cystoscopy while the bleeding is persistent. [ABSTRACT FROM AUTHOR]

Objective: Nephrostomy tubes (NTs) inserted in emergency settings by interventional radiologists are frequently unsuitable for subsequent percutaneous nephrolithotomy (PCNL). We report a novel method of adjusting these NTs to be used as PCNL tracts and avoid renal repuncture. Patients and Methods: A retrospective search of 981 consecutive PCNLs performed in our institution between 2002 and 2017 identified all patients with preoperatively inserted NTs. The NTs unsuitable for PCNL were adjusted by a novel approach in which a 5-mm incision was made at the ideal puncture location (IPL) as indicated under fluoroscopic guidance. The preinserted NT was removed after passing a guidewire into the kidney. A dissector clamp was introduced through the entry wound of the removed NTs to bluntly dissect a retroperitoneal tunnel and pull out the distal tip of guidewire through the IPL, while its proximal segment was maintained in the kidney. The newly positioned guidewire was used for PCNL tract preparation without repuncturing the kidney. Results: The NTs were located in the mid calix, lower calix, and renal pelvis in 6 (26%), 13 (57%), and 4 (17%) cases, respectively. The NT was suitable for PCNL in 5 (22%) cases, a new renal access was performed in 3 (13%), and the novel adjustment approach was used in 15 (65%), all successfully. The place of entry was moved an average of 6 cm (range 47) and the angle between the tract axis and the calix axis was reduced by 65° in average. The procedure was done uneventfully in an average of 4 minutes. Conclusions: The novel method of adjusting preoperatively inserted NTs for PCNL by repositioning their original entry location to the IPL offers the possibility of avoiding kidney repuncture. It is feasible, safe, and easy to implement, and it spares potential morbidity related to additional puncturing of the kidney. [ABSTRACT FROM AUTHOR]

Introduction: Kidney stone disease in the pediatric setting is rare, but the incidence is rising. Mini-percutaneous nephrolithotomy (mPCNL) is one of the newer surgical interventions to have been developed in recent decades. The aim of this study was to carry out a systematic review (SR) to formally evaluate the safety and efficacy of pediatric mPCNL, which was defined as PCNLs using tract size between 15F and 20F. Methods: An SR was carried out in accordance with Cochrane guidelines and A MeaSurement Tool to Assess systematic Reviews (AMSTAR) checklist. Original studies reporting on outcomes of mPCNL with 20 or more patients (aged ≤18 years) were included. Results: Eight studies were finally identified, which satisfied our predefined criteria. This included two randomized trials and six cohort studies. A total of 384 patients with a weighted mean age of 7.5 years (range: 0.5–18 years) and a male:female ratio of 3:2 underwent mPCNL. The weighted mean stone size was 1.2 cm (range: 0.8–3.5 cm). The weighted mean operative time and length of hospital stay were 76.8 minutes (range: 20–120 minutes) and 4.6 days (range: 1–33 days), respectively. The most common location(s) of stones were lower pole (57%) and renal pelvis (24.3%). The weighted mean initial and overall stone-free rates were 87.9% (range: 76%–97.5%) and 97% (range: 91.3%–100%), respectively. None of the cases required intraoperative conversion to standard PCNL. Complications occurred in 19% (n = 73) of patients. The weighted mean transfusion rate reported across studies was 3.3% (range: 0%–10.3%). Conclusions: mPCNL is safe and effective in the pediatric population. Further randomized studies will help determine its formal role in pediatric endourology and help guideline recommendations accordingly. [ABSTRACT FROM AUTHOR]

Introduction: The current study evaluated the efficacy and safety of external physical vibration lithecbole (EPVL) after extracorporeal shock wave lithotripsy (SWL) or retrograde intrarenal surgery (RIRS) for urolithiasis. Methods: Publicized literature was systematically searched from EMBASE, Cochrane Library, PubMed, ScienceDirect, ClinicalTrials.gov, and Web of Science up to February 2020. Fixed-effects or random-effects model was chosen in risk ratio (RR) calculation according to heterogeneity. Quality of evidence was estimated under the guidance of Cochrane handbook. Stone expulsion rate, stone-free rates (SFRs), and complication rates were set as end points. Results: Six randomized controlled trials, including 853 patients, were eligible for analysis. EPVL significantly increased SFR within 3 weeks (RR = 1.17, 95% CI: 1.06–1.29, P = 0.001) and above 3 weeks (RR = 1.19, 95% CI: 1.03–1.37, P = 0.02) after SWL. EPVL also improved SFR within 3 weeks (RR = 1.84, 95% CI: 1.35–2.49, P < 0.0001) and above 3 weeks (RR = 1.53, 95% CI: 1.33–1.77, P < 0.00001) after RIRS. Besides, EPVL can significantly increase SFRs for stones in renal pelvis, lower calix, and multiple locations (all P-value <0.05). Although the overall complication rate was not significantly higher in EPVL + RIRS group, it was found to be 1.38 times higher in EPVL+SWL group (RR = 1.38, 95% CI: 1.06–1.79, P = 0.02), especially the incidence of flank pain (RR = 3.11, 95% CI: 1.02–9.46, P = 0.05). Conclusions: EPVL is effective and safe with high SFRs (especially in renal pelvis, lower calix, and multiple locations) after SWL or RIRS and lower overall complication rate after RIRS in patients with urolithiasis. However, the overall complication rate (especially the incidence of flank pain) was higher after EPVL + SWL. [ABSTRACT FROM AUTHOR]

Objective: To investigate the outcomes of retrograde flexible ureteroscopy in managing parapelvic renal cysts and speculate the factors affecting therapeutic efficacy. Methods: Thirty-eight patients with parapelvic renal cysts were recruited and underwent retrograde flexible ureteroscopy using holmium laser. Parapelvic cysts were divided into peripheral type and central type based on the position of cyst convex to the perirenal tissue. Feasibility and safety were retrospectively evaluated, and cases were analyzed to detect their distinctive characteristics. Independent-sample t-test and chi-square test were undertaken for continuous variables and categorical variables, respectively. Results: Radiologic evidence of success was achieved in 31 (81.58%) cases after a mean follow-up of 14.4 months (range 6–26 months). No significant perioperative complications were identified. There were seven cases with features of peripherally located parapelvic cyst. Four cysts shown as irregular protrusion were unable reduce to less half of previous size. Reductions were recorded in the other three patients with spherically peripheral protrusion. There was significant difference between these two types (p = 0.029). Among the 31 patients with centrally located parapelvic cyst, 28 of these have simple cysts that achieved radiologic success and 3 of the 31 patients were identified as failed cases indicated by renal pelvis enveloped by cyst on radiologic investigation. The success rate of simple cysts was significantly higher than that of the later type (p < 0.001). Conclusion: The location and shape of parapelvic cyst may play a critical role in the radiologic outcome of internal incision and patients with simple central or spherical peripheral cyst may benefit more from retrograde flexible ureteroscopy combined with laser incision. [ABSTRACT FROM AUTHOR]

This article is a comment on a previously published study about a novel technique for managing encrusted or knotted retained ureteral stents. The authors share a case study of a 7-year-old female child who underwent bladder reconstruction and experienced complications with a ureteral stent. They successfully used the telescopic access sheath method through a Monti's conduit to remove and replace the stent. The authors believe that this technique is effective, even in pediatric patients, and is valuable due to the limited access to the Monti stoma. The article includes references on the effects of ureteral stent changes in a Monti stoma. [Extracted from the article]

Introduction: Surgeons and residents report using videos to prepare for procedures, with a preference for open access resources, specifically YouTube. The educational quality of online videos is uncertain. Videos are uploaded without quality assessment, and ranked by popularity. This study aims to better characterize the available pediatric robotic pyeloplasty videos on YouTube, and assess for conformity to LAParoscopic surgery Video Educational GuidelineS (LAP-VEGaS). Methods: The most viewed videos of "pediatric robotic pyeloplasty" on YouTube were reviewed for baseline characteristics, educational content, inclusion of critical domains of the procedure (positioning, ports, exposure, ureteral mobilization, renal pelvis dissection, hitch stitch, spatulation, and anastomosis), and conformity to LAP-VEGaS. Results: Once ranked by views, 23 videos met inclusion criteria. Views per video ranged from 40 to 15,664 (mean of 1912). The two oldest videos were uploaded in 2009, and had the highest number of views. Audio and written educational content accompanied videos, 22% and 48% of the time, respectively. United States and India were the most common countries of origin. Only six videos contained all critical steps of the procedure. No videos contained all 16 points of the LAP-VEGaS essential checklist (mean 7.6), and most videos neglected preoperative information and outcomes. Percentage conformity was 48% overall (range for each video was 25%–81%). The most viewed videos were not associated with higher conformity to LAP-VEGaS. Conclusions: Despite studies demonstrating preferences for YouTube videos as an educational tool, and pyeloplasty being the most commonly performed pediatric robotic procedure, there are currently few high value educational videos available on YouTube. Videos often lack important procedure domains, and demonstrate low conformity to LAP-VEGaS guidelines. This demonstrates an opportunity to improve the educational quality and value of open access videos, starting by adopting established video reporting guidelines. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the onlay technique using the appendix for ureteral reconstruction and describe the initial experience of nine operations performed by one surgeon. Methods: Nine patients with complex ureteral strictures who underwent appendiceal onlay flap ureteroplasty since May 2019 were recruited from our RECUTTER database. There were seven men and two women, with a mean age of 38.9 years; four patients underwent robot-assisted laparoscopic surgery, and five patients underwent traditional laparoscopic surgery. All patients had iatrogenic injuries of the ureter after treatment of stone disease. Seven patients had proximal ureteral strictures, and two had midureteral strictures. The mean stricture length of the nine patients was 3.9 (range 3–4.5) cm. Nephrostomy was performed in seven patients before they presented to our center, and the other two patients had indwelling Double-J ureteral stents. Results: All nine operations were effectively completed without open conversion. The mean operation time was 182 (range 135–220) minutes, the mean estimated blood loss was 71 (range 20–100) mL, and the mean length of postoperative hospital stay was 9 (range 6–12) days. No postoperative complications of high grade (Clavien– Dindo III and IV) occurred within 30 days of surgery. All the patients had their Double-J ureteral stents and nephrostomy tubes removed after complete ureteroscopy and upper urinary tract urodynamic examination or CTU, which showed that the anastomosis healed well and that the urinary tract was unobstructed, respectively. The objective success rate was 100% (all the patients had endoscopic and radiographic resolution of their ureteral strictures). The subjective success rate was 88.9% (one patient developed recurrent back discomfort and a 0.5 cm calculus was found in her renal pelvis). Conclusions: Appendiceal onlay flap ureteroplasty is a viable and effective technique for treating complex proximal and middle ureteral strictures at the right side. [ABSTRACT FROM AUTHOR]

Purpose: In urolithiasis patients, preoperative non-contrast computed tomography (NCCT) commonly fails to provide sufficient distention of the renal collecting system to allow reliable preoperative planning for how best to approach a stone. Our objective was to evaluate the effect of a novel protocol, including oral hydration and an oral diuretic, on the distention of the renal collecting system. Patients and Methods: Twenty patients with a prior NCCT, who were scheduled to undergo a subsequent NCCT for urolithiasis assessment, were enrolled. Each patient was instructed to ingest 1 L of water and 20 mg of oral furosemide 30 to 60 minutes before their scan (DRINK [DiuResIs Enhanced Non-contrast Computed Tomography for Kidney Stones] protocol). Patients' prior NCCT scan (non-DRINK) was used for comparison. Three-dimensional (3D) reconstruction of DRINK and non-DRINK NCCT studies was performed to determine the volume and surface area of the collecting system. In addition, three faculty endourologists measured the width of the upper and lower pole infundibula and renal pelvis in the axial, coronal, and sagittal views. Results: Among the 20 patients, 13 completed the DRINK protocol as specified. For these 13 patients, 3D reconstruction of the DRINK study collecting systems showed a 63% and a 36% increase in collecting system volume and surface area, respectively (p = 0.02 and p < 0.01, respectively). Also, measurements of the CT images demonstrated a significant (p < 0.05) increase in the collecting system widths in 67% of measurements. Conclusion: The DRINK protocol significantly increased the visible collecting system volume and surface area; in the majority of cases, the upper and lower pole infundibular widths and the width of the renal pelvis were also expanded. [ABSTRACT FROM AUTHOR]

Introduction and Objective: Current available lithotrites have clinical stone clearance rates averaging 24 to 32 mm2/minute. The objective of this study was to critically evaluate the initial experience with the Swiss LithoClast® Trilogy lithotrite during percutaneous nephrolithotomy (PCNL). Methods: We prospectively enrolled patients with a minimum of 15 mm of stone in axial diameter at three locations (Indiana University, University of California Davis, and University of California San Diego) scheduled to undergo PCNL for nephrolithiasis over a 60-day trial period. We assessed objective measures of stone clearance time, stone clearance rate, device malfunction, stone-free rate, and complications. Each surgeon also evaluated subjective parameters from each case related to the use of Trilogy on a 1 to 10 scale (10 = extremely effective), and compared it with their usual lithotrite on a 1 to 5 scale (5 = much better). Results: We included 43 patients and had 7 bilateral (16.3%) cases, for a total of 50 renal units. One case was a mini-PCNL. Two cases experienced device malfunctions requiring troubleshooting but no transition to another lithotrite. The mean stone clearance rate was 68.9 mm2/minute. The stone-free rate on postoperative imaging was 67.6% (25 of 37 patients with available imaging). The lowest subjective rating was the ergonomic score of 6.7, and the highest subjective rating was the ease of managing settings score of 9.2. The surgeon impressions of ultrasound (7.3), ballistics (8.1), combination of ultrasound and ballistics (8.7), and suction (8.4) were high. One patient experienced an intraoperative renal pelvis perforation, one patient required a blood transfusion, one patient had a pneumothorax requiring chest tube placement, and one patient had a renal artery pseudoaneurysm requiring endovascular embolization. Conclusions: This multi-institutional study evaluated a new and efficient combination lithotrite that was perceived by surgeons to be highly satisfactory, with an excellent safety and durability profile. [ABSTRACT FROM AUTHOR]

Introduction: High-power laser settings are commonly employed for stone dusting techniques. Previous in vitro and in vivo studies have demonstrated that a toxic thermal dose can result from treatment within a renal calix without adequate irrigation. Hence, both laser power and irrigation rate must be considered together to determine safe laser lithotripsy parameters. The objective of this in vitro study was to map parameter safety boundaries and create guidelines for selection of safe laser and irrigation settings. Methods: The experimental system consisted of in vitro models simulating ureter, renal calix, and renal pelvis placed in a water bath maintained at 37°C. Temperature was recorded during ureteroscopy with laser activation for 60 seconds. Trials were conducted at strategically selected power levels and irrigation rates. Thermal dose for each trial was calculated based on Sapareto and Dewey t43 methodology with thermal dose >120 equivalent minutes considered to result in thermal tissue injury. A parameter safety boundary was established by plotting the maximal safe power level for each irrigation rate. Results: The parameter safety boundary was found to be linear for each scenario with the renal pelvis able to tolerate the highest laser power and the renal calix the least power without injury. Conclusion: This study describes the methodology to determine parameter safety boundaries that can be used to guide proper selection of thermally safe laser settings and irrigation rates during ureteroscopy with laser lithotripsy. This work provides a framework to assess the effectiveness of various strategies to control and mitigate thermal dose. [ABSTRACT FROM AUTHOR]

Introduction: MOSES™ technology is a holmium:yttrium-aluminum-garnet laser pulse mode shown to minimize stone retropulsion. This may facilitate lithotripsy at higher power settings. However, power and heat production are proportional, and temperatures capable of tissue injury may occur during ureteroscopic lithotripsy. Although previous in vitro studies demonstrate the importance of irrigation and activation time on heat production, the impact of pulse type has not been evaluated. Methods: A flexible ureteroscope with a 365 μm laser fiber was placed in an 11/13 F access sheath inserted into a 50 mL saline bag to simulate a ureter, renal pelvis, and antegrade irrigant flow. A thermocouple was placed adjacent to the laser tip, and the laser fired for 30 seconds at 0.6 J/6 Hz, 0.8 J/8 Hz, 1 J/10 Hz, 1 J/20 Hz, and 0.2 J/70 Hz at irrigation pressure of 100 mmHg. Four runs were tested per setting using short pulse, long pulse (LP), MOSES-contact (MC), and MOSES-distance (MD) modes. The mean temperature changes (dT) were compared and thermal dose was calculated in cumulative equivalent minutes at 43°C (CEM43) using an adjusted baseline of 37°C. CEM43 ≥ 120 minutes was considered the tissue injury threshold. Results: At 0.8 J/8 Hz, LP produced the greatest dT, significantly higher than MC (p = 0.041). CEM43 did not exceed the injury threshold. At 1 J/10 Hz, dT was significantly higher for LP versus MC and MD (p = 0.024 and 0.045, respectively). Thermal dose remained below the injury threshold. No differences in dT were seen between pulse types at 0.6 J/6 Hz, 0.2 J/70 Hz, or 1 J/20 Hz. At 1 J/20 Hz, thermal dose exceeded the injury threshold for all pulse types within 3 seconds. Conclusions: Laser pulse type and length seemed to impact heat production in our ureteral model. LP produced significantly greater temperatures at 0.8 J/8 Hz and 1 J/10 Hz relative to MOSES settings. Fortunately, thermal dose remained safe at these settings. Both LP and MOSES technology have been shown to reduce stone retropulsion. At power ≤10 W, the latter may confer this advantage with decreased heat production. [ABSTRACT FROM AUTHOR]

Introduction: Temperatures over 43°C—the threshold for cellular injury—may be achieved during ureteroscopic holmium laser lithotripsy. The time to reach and subsequently clear high temperatures at variable laser power settings and irrigation pressures has not been studied. Methods: A flexible or semirigid ureteroscope was placed within an 11/13 F ureteral access sheath inserted into a 250-mL saline bag simulating a normal-caliber ureter, renal pelvis reservoir, and antegrade irrigation flow. A thermocouple was placed adjacent to a 365 μm fiber fired for 45 seconds at 0.6 J/6 Hz, 0.8 J/8 Hz, 1 J/10 Hz, 1 J/20 Hz, and 0.2 J/80 Hz. Irrigation pressures of 200, 100, and 0 mm Hg were tested. Mean temperature changes were recorded with 6°C increase as a threshold for injury (as body temperature is 6°C below 43°C). Results: Semirigid scope: At 200 mm Hg no temperature changes >6°C were observed. At 100 mm Hg, changes >6°C occurred with 1 J/20 Hz within 1 second of activation and returned to ≤6°C within 1 second of cessation. At 0 mm Hg, changes >6°C occurred with all settings; within 1 second at power ≥10 W. Temperatures returned to ≤6°C within 5–10 seconds. Flexible scope: At 200 mm Hg, changes >6°C occurred at 1 J/10 Hz (15 seconds), 0.2 J/80 Hz (3 seconds), and 1 J/20 Hz (2 seconds). Temperatures returned within 6°C of baseline within 2 seconds. At 100 mm Hg, changes >6°C occurred in all but 0.6 J/6 Hz. Temperatures returned to ≤6°C in 5–10 seconds. At 0 mm Hg, all settings produced changes >6°C within 3 seconds, except 0.6 J/6 Hz (35 seconds). Temperatures returned to ≤6°C in under 10 seconds. Conclusions: High temperatures were achieved in our in vitro model in as little as 1 second at common irrigation pressures and laser settings, particularly with a flexible ureteroscope and power ≥10 W. However, with laser cessation, temperatures quickly returned to a safe level at each irrigation pressure. [ABSTRACT FROM AUTHOR]

Objectives: To assess the effect of irrigation settings and the size of ureteral access sheath (UAS) on the maximal intra-pelvic pressure (IPPmax) during ureteroscopy (URS) in pigs. Materials and Methods: In supine position, three anesthetized female pigs underwent cystoscopy to insert a 6F ureteral catheter in each ureter. Pigs were then turned to prone position to establish a percutaneous access, insert a 10F nephrostomy tube in the kidney, and connect it to a urodynamic device. An 8F semi-rigid ureteroscope or the Flex-X2 Flexible Ureteroscope was used with two irrigation settings: gravity flow and manual pumping using a commercial pump. URS was performed without UAS and with the UAS 9.5/11, 12/14, 14/16 at the ureteropelvic junction and the IPPmax was recorded. Results: Under gravity irrigation, the recorded IPPmax during semi-rigid URS in the distal ureter and the renal pelvis was 0 and 30 cmH2O, respectively. Further, the IPPmax during flexible URS in the renal pelvis without UAS, with UAS 9.5/11.5, with UAS 12/14, and with UAS 14/16 was 23, 6, 2, and 1 cmH2O, respectively. Under manual pumping, the IPPmax during semi-rigid URS in the distal ureter and the renal pelvis was 84 and 105 cmH2O, respectively. Further, the IPPmax during flexible URS in the renal pelvis without UAS, with UAS 9.5/11.5, with UAS 12/14, and with UAS 14/16 was 45, 46, 18, and 1 cmH2O, respectively. Conclusion: Manual pumping can significantly increase the IPPmax to unsafe levels during URS. The UAS can significantly decrease the IPPmax, even under manual pumping. The larger the UAS, the lower the IPPmax. The use of UAS can render URS safer by acting as a safeguard against the consequences of increased IPP, even under forced irrigation. [ABSTRACT FROM AUTHOR]

Introduction and Objectives: Ureteral injuries can occur during ureteral access sheath (UAS) deployment. The force exerted during deployment and the amount of force that results in ureteral injury is yet to be accurately quantitated. In this feasibility study, we developed and then tested a novel force-sensing device in our animal laboratory to identify the threshold force that results in a porcine ureteral injury. Methods: With Institutional Animal Care and Use Committee approval, we measured ureteral dilator and UAS deployment force using our proprietary University of California, Irvine Ureteral Access Sheath Force Sensor (UAS-FS). The exerted force was measured during deployment from the moment that the tip of the UAS was passed into the urethral meatus until it reached the renal pelvis; progression of the UAS along the ureter was monitored with fluoroscopy. Ureteroscopic evaluation was performed after deployment of each catheter/sheath ≥8F to assess for ureteral injury using the Postureteroscopic Lesion Scale (PULS). Results: Six juvenile Yorkshire female pigs (12 ureters) were studied. No injuries were detected when the deployment force was <4 Newtons (N), which was the case when the catheter/access sheath was ≤13F. Increasing UAS size >13F resulted in greater peak forces. In five of the pigs, ureters selected for 14F UAS deployment without previous sequential dilation were injured (PULS ≥3) at a mean threshold force of 4.84 N. Serial dilation had a higher threshold for PULS ≥3 at 5.56 N. Overall, injury of PULS ≥3 was routinely noted when the force applied exceeded 8.1 N. Conclusions: The UAS-FS reliably measured forces while deploying a UAS. Significant ureteral injury can routinely be avoided if the applied force is <4.84 N; PULS ≥3 routinely occurred when forces exceeded 8.1 N. Serial dilation may allow safe passage at higher deployment forces, as much as 5.56 N. [ABSTRACT FROM AUTHOR]

Purpose: Holmium laser lithotripsy is a common modality used to fragment urinary stones during ureteroscopy. Laser energy deposited during activation produces heat and potentially causes thermal bioeffects. We aimed to characterize laser-induced heating through a computational simulation. Materials and Methods: A finite-element model was developed and used to estimate temperature in the urinary tract. Axisymmetric models of laser lithotripsy in a renal calyx, the renal pelvis, and proximal ureter were created. Heat generation by laser and heat transfer were simulated under different laser powers between 5 and 40 W. Irrigation fluid flow was introduced at rates between 0 and 40 mL/min. The model was validated by comparison with previous in vitro temperature data in a test tube, then used to calculate heating and thermal dose in the three tissue models. Results: Simulated temperature rises agreed well with most in vitro experimental measurements. In tissue models, temperature rises depended strongly on laser power and irrigation rate, and to a lesser extent on location. Injurious temperatures were reached for 5–40 W laser power without irrigation, >10 W with 5 mL/min irrigation, 40 W with 15 mL/min irrigation, and were not found at 40 mL/min irrigation. Tissue injury volumes up to 2.3 cm3 were calculated from thermal dose. Conclusions: The results suggest a numerical model can accurately simulate the thermal profile of laser lithotripsy. Laser heating is strongly dependent on parameters and may cause a substantial temperature rise in the fluid in the urinary tract and surrounding tissue under clinically relevant conditions. [ABSTRACT FROM AUTHOR]

Introduction: A novel semirigid ureterorenoscope, named the Sotn ureterorenoscope, was designed with a vacuum suction system. The present study aimed to evaluate the feasibility and safety of using the Sotn ureterorenoscope to manage single proximal ureteral or renal pelvic stones. Patients and Methods: Data were retrospectively collected from consecutive patients treated with a Sotn ureterorenoscope between February 2010 and August 2015 at Sun Yat-sen Memorial Hospital of Sun Yat-sen University and Jiangmen Wuyi Traditional Chinese Medicine Hospital in China. The primary outcome was the primary stone-free rate (SFR) in 1 month. The secondary outcomes were the final SFR and the perioperative complication rate. Results: A total of 386 patients were evaluated, including 240 males and 146 females. The median (interquartile range [IR]) age was 50 (40–59) years. There were 96 and 290 stones located in the renal pelvis and proximal ureter, respectively. The median (IR) operative time and console time for all patients were 40 (30–70) and 20 (12–38) minutes, respectively. The primary overall SFR was 86.5%, whereas the SFRs for stones with a diameter of ≤1, 1 to 2, and 2 to 3 cm were 95.7%, 86.9%, and 69.0%, respectively. Complications occurred in 90 patients (23.3%); these complications were classified as Clavien–Dindo grades 1 to 2 (minor) in 79 (20.5%) patients, and grades 3 to 4 (major) in 11 (2.8%). Conclusions: The novel semirigid Sotn ureterorenoscope featuring a vacuum suction system is effective and safe for managing proximal ureteral and renal pelvic stones. [ABSTRACT FROM AUTHOR]

We herein propose a nomenclature for renal calices and anatomical classification of the renal pelvis for endoscopic surgery. We prospectively collected data on a total of 270 patients (540 kidneys) who underwent CT-urography. We then constructed three-dimensional images of the renal pelvis and examined their morphologic classification. Forty-eight kidneys were excluded from this study because of severe hydronephrosis or large renal cysts. The remaining 492 kidneys were included. We systematically categorized each minor calix into five levels: top, upper, middle, lower, and bottom. The upper, middle, and lower calices were typically found in pairs: anterior and posterior. The most common total number of minor calices was eight (51%), followed by seven (30%). We also classified the form of the pelvis into type I: single pelvis (58%) and type II: divided pelvis (42%), according to the branch patterns of the renal pelvis. In type II, the renal pelvis is always bifurcated into the upper branch (top and upper) and lower branch (middle, lower, and bottom). Type I was subclassified into three types: type Ia (43%), the standard type; type Ib (4%), with a wide pelvis; and type Ic (11%), with a narrow pelvis. This anatomical classification can divide the renal pelvis into two major types (subdivided into four types) and name each minor calix. This simple classification enables to share common intrarenal information, thus leading to the development of concrete treatment strategies. [ABSTRACT FROM AUTHOR]

Objective: To determine how sheath and endoscope size affect intrarenal pelvic pressures and risk of postoperative infectious complications comparing “Mini” vs “Standard” percutaneous nephrolithotomy (PCNL). Materials and Methods: Uropathogenic Escherichia coli were grown and 109 of them were instilled into the porcine renal pelvis through retrograde access for 1 hour. Percutaneous access utilized a 14/16F 20 cm ureteral access sheath for the Mini arm and a 30F sheath for the Standard arm. Nephroscopy was simulated utilizing either an 8/9.8F semirigid ureteroscope or 26F nephroscope for 1 hour while intrarenal pelvic pressure was continuously monitored. Blood and tissue cultures of kidney, liver, and spleen biopsies were plated and incubated and positive cultures were confirmed with polymerase chain reaction. Results: Intrapelvic pressures were higher in the Mini group, 18.76 ± 5.82 mm Hg vs 13.56 ± 5.82 mm Hg (p < 0.0001). Time spent above 30 mm Hg was greater in the Mini arm, 117.0 seconds vs 66.1 seconds (p = 0.0452). All pigs had positive kidney tissue cultures whereas spleen cultures were positive in 100% and 60% of pigs in the Mini and Standard arms, respectively (p = 0.0253); 90% and 30% had positive liver tissue culture in the Mini and Standard arms, respectively (p = 0.0062). Blood cultures were positive in 30% of pigs in the Mini arm compared with none in the Standard arm (p = 0.0603). Conclusion: Mini-PCNL was associated with higher intrarenal pressures and higher risk of end organ bacterial seeding in the setting of an infected collecting system. This suggests a higher potential for infectious complications in a clinical setting. [ABSTRACT FROM AUTHOR]

Purpose: To describe the technique of laparoscopic in situ dismembered pyeloplasty as a modified technique during which the alignment of ureter and renal pelvis remains intact during ureteropelvic junction (UPJ) anastomosis. We also assessed intraoperative and postoperative outcomes of this modification in comparison to standard laparoscopic dismembered pyeloplasty. Patients and Methods: Patients with significant primary UPJ obstruction without any history of abdominal surgery, high ureter insertion, or renal anomalies were considered. The patients were consecutively enrolled one after another into one of two study groups: classic laparoscopic dismembered pyeloplasty (Group I) or laparoscopic in situ dismembered pyeloplasty (Group II), however, those with aberrant vessels crossing the UPJ were allocated specifically to Group I because UPJ anastomosis should be done anterior to the aberrant vessels. Demographic data, intraoperative timings, and postoperative and follow-up outcomes were compared in the two groups. Results: Patients in Group I (n = 23) and Group II (n = 14) had similar demographic characteristics. Mean operative time was significantly longer in Group I (103.8 - 19.95 minutes vs 89.5±18.90 minutes, p = 0.038). Total duration of UPJ repair and anastomosis was also significantly longer in Group I (92.7±15.82 minutes vs 78.4±14.76 minutes, p = 0.021). The method of pyeloplasty significantly affected the time required to prepare ureter and renal pelvis (p = 0.017) and the duration of UPJ anastomosis (p = 0.014). Both were shorter in Group II. Mean follow-up period was 14.4±7.42 months in Group I and 14.05±7.93 months in Group II (p = 0.88). Success rate was 95.6% in Group I and 100% in Group II (p = 0.42). Conclusion: Laparoscopic in situ pyeloplasty is a safe and effective approach that can help simplify laparoscopic pyeloplasty, especially at teaching centers where surgeons with variable levels of experience perform laparoscopic procedures. [ABSTRACT FROM AUTHOR]

Objective: To determine trends in pyelolithotomy, evaluate risk factors for complications, and evaluate the difference in outcomes and charges between open and minimally invasive (MI) techniques. Patients and Methods: We used the Nationwide Inpatient Sample to identify patients with a diagnosis of having nephrolithiasis undergoing pyelolithotomy from 2008 to 2012. Total charges were inflation-adjusted to U.S. dollars in 2012. Patient demographics, hospital characteristics, and outcomes were reported and compared between open and MI groups after survey weighting. Results: We included a survey-weighted population of 17,294 patients, of whom 841 (4.9%) had MI pyelolithotomy. The proportion of MI cases increased by 2.57% annually ( r2 = 0.921, p = 0.01), although total pyelolithotomy cases remained stable. Simultaneous pyeloplasty occurred in 6.6% of all patients. Patients receiving open surgery experienced longer length of stay (3.9 days vs 2.7 days; p < 0.001), but accrued equivalent inflation-adjusted charges ($49,588 ± 2088 vs $51,716 ± 4893; p = 0.665). On multivariable analysis, higher Elixhauser comorbidity index and presence of any genitourinary anomaly were associated with experiencing a complication, while undergoing surgery at a top quartile hospital and elective admission status were protective against complications. MI technique and simultaneous ureteropelvic junction repair did not alter complication risk. Conclusion: While the annual number of pyelolithotomy cases was stable, there was an increasing trend toward MI technique. Both patient and hospital factors can significantly alter the risk for complications following pyelolithotomy. [ABSTRACT FROM AUTHOR]

Introduction: Intracorporeal suturing is considered to be the most challenging aspect of laparoscopic and robotic surgery. To overcome this problem, barbed self-retaining sutures have been effectively employed in various minimally invasive endourologic surgeries. However, the use of this suture has been recently cautioned for pyeloplasty due to a high failure rate. Our objective was to report our experience using barbed suture during robotic pyeloplasty. Methods: We retrospectively identified 13 consecutive patients who underwent robotic pyeloplasty with a barbed monofilament (4-0 V-Loc™) suture for the ureteropelvic anastomosis from 2011 to 2014. We compared these patients to 12 consecutive patients who underwent robotic pyeloplasty with a 4-0 nonbarbed suture from 2007 to 2011. We evaluated patient demographics, operative times, preoperative and postoperative symptoms, renal function, and diuretic renograms (DRG). Successful repair was defined as resolution of preoperative symptoms and/or T½ improvement on DRG to less than 20 minutes. Results: The median age was 26 (interquartile range [IQR] 20.7-38) years and 35 (IQR 18.3-44) years for the barbed and nonbarbed suture groups, respectively. In the barbed suture group, preoperative DRG revealed ureteropelvic junction obstruction (UPJO) in 11 patients, equivocal UPJO (T½ 10-20 minutes) in one patient, and no obstruction in one patient. In the nonbarbed group, preoperative DRG revealed UPJO in 10 patients, equivocal UPJO in one patient, and no obstruction in one patient. In the barbed suture group, postoperative DRG was obtained in 11 patients, which showed no obstruction in 10/11 patients with 92% of patients experiencing symptom resolution. Similarly, postoperative DRG was obtained in 11 patients in the nonbarbed group, which showed no obstruction in 10/11 patients with 100% postoperative symptom resolution. Conclusions: In the largest series reporting use of V-Loc suture for robotic pyeloplasty, the V-Loc suture was safely and effectively used for robotic pyeloplasty repair. [ABSTRACT FROM AUTHOR]

Introduction: Failure after pyeloplasty is difficult to manage. We report our experience managing pyeloplasty failures. Methods: We retrospectively reviewed the case log of a single surgeon, from August 1996 to August 2014, to identify all patients undergoing a surgical procedure after failed pyeloplasty. We excluded patients without follow-up exceeding 1 year from initial postpyeloplasty procedure. Failure was defined as a need for additional definitive intervention. Results: Of 247 laparoscopic pyeloplasties, 68 endopyelotomies and 305 simple laparoscopic nephrectomies reviewed, 41 were performed after previous pyeloplasty and had sufficient follow-up. Laparoscopic nephrectomy was performed in nine patients. All three secondary laparoscopic pyeloplasties were successful. Of 29 secondary endopyelotomies, 10 (34%) were successful. Of the 19 failures after secondary endopyelotomy, 12 patients had tertiary pyeloplasty (5 laparoscopic and 7 open surgical), 5 (26%) underwent tertiary endopyelotomy, and 2 (11%) required nephrectomy. Our overall endopyelotomy success rate was 38% (13/34) vs 100% (11/11) for secondary or tertiary pyeloplasty (4 patients lost to follow-up). Median time to failure was 5 months for endopyelotomy. Median follow-up for patients free from intervention was 40.2 months. Conclusions: Secondary pyeloplasty (including both laparoscopic and open surgical approach) is more than twice as successful as endopyelotomy after failed pyeloplasty. Secondary pyeloplasty is an excellent alternative to endopyelotomy in select patients with failure after initial pyeloplasty. [ABSTRACT FROM AUTHOR]

Introduction: The current experimental study aimed at evaluating the temperature raise of the irrigation fluid caused by the use of the thulium (Tm:YAG) and holmium laser (Ho:YAG) in the upper urinary tract (UT) of pigs. Materials and Methods: An experimental setting was designed for the investigation of differences in the temperature of the irrigation fluid in the renal pelvis of a porcine model under different flow rates and laser power settings. The experimental configuration included a single-use flexible ureteroscope, a Tm:YAG and a Ho:YAG laser system. A thermocouple was inserted through a 6F ureteral catheter that was placed parallel to the FlexVue in the renal pelvis. An additional thermocouple was placed next to the renal pelvis after open preparation of the kidney. Irrigation was achieved with either the irrigation bags placed 1 m above the level of the pig or with the use of an irrigation pump (30 and 60 compressions per minute). Results: Tm:YAG (10, 20, 30, 40 W): The higher flow provided by the pump system minimized the increase of temperature within the renal pelvis regardless of the laser power. The external temperature increase was lower in comparison to the increase inside the renal pelvis. The internal temperature could increase up to 10.5°C from a baseline value of 23°C. Ho:YAG (10, 20 W): There was no temperature change or an increase of only 2.1°C under the different power and irrigation flow rate settings. There were no differences in the temperature between the inside and outside of the renal pelvis. Conclusion: The use of Tm:YAG in continuous mode with power settings up to 40 W and flow rates similar to those used in the clinical practice seemed to result in temperature increases in the irrigation fluid, which do not represent a risk for the renal tissue during the UT endoscopic surgery. [ABSTRACT FROM AUTHOR]