Ureteral Access Research Articles

First Worldwide Multicentric Series of Mini-Ecirs in Children: Outcomes from two Tertiary Endourology Centers.

Introduction: Endoscopic combined intrarenal surgery (ECIRS) is a combination of both retrograde and antegrade approaches for treatment of large or complex renal stones in one procedure, that are currently being treated with multiple tracts or sessions of percutaneous nephrolithotomy, increasing the complications. The aim of our study is to describe the clinical outcomes of Mini-ECIRS in a pediatric population. Material and Methods: A retrospective study was performed in pediatric patients with lithiasis disease treated with mini-ECIRS between 2006 and 2023 in 2 referral centers in Europe. Demographic data, clinical data, stone size and location, laser settings, intraoperative variables, stone-free rate (SFR) and complications were collected. Pearson's chi-squared test, Fisheŕs test and logistic regression, were performed. Results: A total of 32 mini-ECIRS were included. The mean age was 9,8 years, 56.3% girls. The mean size and volume of the stone were 21.5mm and 3298, 2mm3, 53.1% were multiple. Ureteral access sheath was used in 93.8% of the surgeries and only 37.5% had preoperative JJ stent. 53.1% of percutaneous access were with 14 Fr sheath. High power laser was the most frequent energy source for lithotripsy, including thulium fiber laser. The mean operative time was 166,6 minutes. There was one perforation of the collecting system that was managed with JJ stent and in the postoperative period 81.2% of the patients had no complications. Three presented fever, 1 developed urinary sepsis, and 1 required reintervention. The SFR was 75% and the size, volume, hardness, and complexity of the lithiasis, as well as the non-use of lithotripsy in the retrograde approach were statistically significant in decreasing the success of the surgery. Conclusions: ECIRS is a feasible, safe, and efficient procedure in children with complex renal lithiasis, decreasing the number of procedures needed for stone free. Multicenter studies are required to validate these results on a population scale.

Foley catheter after ureteroscopy and JJ stent placement: a randomised prospective European Association of Urology Section of Urolithiasis-Young Academic Urologists (EULIS-YAU) endourology study.

To evaluate the effects of inserting a Foley catheter after ureteroscopy (URS) and JJ stent placement on pain scores, voiding patterns, biochemical parameters and postoperative complications. A randomised clinical trial (1:1) with adult patients following unilateral URS + JJ stent placement was planned. In Group A, no Foley catheter was placed, in Group B, a Foley catheter was placed following URS + JJ stent placement. The primary objective was to evaluate effect of placing a Foley catheter on International Prostate Symptom Score (IPSS), Ureteric Stent Symptom Questionnaire (USSQ) score and postoperative biochemical parameters. The secondary objective was to evaluate postoperative complications. A total of 112 patients were included (56/group). A ureteric access sheath was used in each patient. Patients had similar demographic and surgical parameters. The pre- and postoperative biochemical analyses including white blood cell count, C-reactive protein, procalcitonin and creatinine levels were similar between the two groups. The IPSS were similar between the two groups. All the subdomains of the USSQ were similar between two groups except Total Body Pain score, which was lower in Group B. The visual analogue scale scores were similar. Complications were all Clavien-Dindo Grade I and II, and the complication rate was 5.4% and 8.9% in Group A and B, respectively. Placing a Foley catheter following URS + JJ stent placement did not show significant effects on postoperative biochemical parameters and voiding symptoms. However, a Foley catheter lowered the Total Body Pain score on the USSQ without having significant effects on VAS scores. The practice of placing a Foley catheter following URS and JJ stent placement should be based on surgeon's preference keeping in mind the potential positive effect on pain scores.

Application of 11/13Fr suctioning ureteral access sheath and 8.55Fr single-use digital flexible ureteroscope in one-stage flexible ureteroscopic lithotripsy: an initial experience of 900 cases.

To report our initial experience of one-stage flexible ureteroscopic lithotripsy(FURL) with 11/13Fr suctioning ureteral access sheath(UAS) and 8.55Fr single-use digital flexible ureteroscope(SDFU) in upper ureteral or renal calculi. We retrospectively collected the clinical data of 900 adult patients with upper ureteral or renal calculi treated by FURL with 11/13Fr suctioning UAS and 8.55Fr SDFU from January 2022 to April 2024. Demographics, peri- and postoperative outcomes were assessed. In all, 40 of 940 cases(4.26%) failed to introduce UAS and required second-stage FURL because of ureterostenosis and were excluded. Mean stones size of the remaining 900 eligible cases was 1.68 ± 0.58cm in greatest diameter. There were 228 cases of upper ureteral stone, 456 cases of renal stone and 216 cases of concomitant ureteral and renal calculi. The mean operation time was 52.20 ± 20.21min and the postoperative hospital stay was 2.87 ± 1.37 days. The stone-free rate of 1 month postoperatively was 89.56% and only 2.44% of patients with residue underwent additional reoperation. The rate of postoperative fever, postoperative pain needing analgesic and slight ureteral mucosal injury were 5.11%, 8.22% and 7.78%, respectively. None of patient suffered from severe complications, such as sepsis or ureteral perforation. It's practical and suitable for the vast majority of adult patients to undergo FURL in single session with 11/13Fr suctioning UAS without preoperative stenting. FURL with 11/13Fr suctioning UAS and 8.55Fr SDFU is feasible, reliable, safe, and efficient in the management of renal stone and upper ureteral stone.

Comparative efficacy and safety of intelligent pressure-controlled versus flexible vacuum-assisted ureteral access sheath for 2-4 cm renal calculi.

Retrograde intrarenal surgery (RIRS) is being increasingly used to treat 2-4 cm renal stones, which can be attributed to advances in flexible ureteroscopes and ureteral access sheaths (UASs). Despite the improvement and application of flexible vacuum-assisted (FV) and intelligent pressure-controlled (IPC) UASs, no studies have compared their therapeutic efficacy and safety. Therefore, this study aimed to compare the therapeutic efficacy and safety of IPC-UAS and FV-UAS in RIRS 2-4 cm renal stones. We included 96 and 103 patients who underwent IPC-UAS and FV-UAS RIRS, respectively, for 2-4 cm renal stones. Stone-free rate (SFR), operative time, and complications were compared between the two groups. The immediate SFR was 69.8% and 82.5% in the IPC-UAS and FV-UAS groups, respectively (P<0.05). There were no significant between-group differences in the 1-month SFR (84.4% vs. 84.5%, P>0.05). The IPC-UAS group had a shorter hospital stay (5.2±2.4 vs. 6.2±3.2 days, P=0.018) and lower cost (CNY13014.7±3240.7 vs. CNY14022.5±2301.6, P=0.012) than the FV-UAS group. There were no significant between-group differences in operative time or complications. Regarding RIRS for 2-4 cm renal stones, the IPC-UAS group can achieve a 1-month SFR similar to that of the FV-UAS group, with shorter hospitalization and lower cost. Additionally, the IPC-UAS is a promising device for efficient and safe RIRS, considering its intelligent pressure regulation. Our findings could inform optimal UAS selection for managing large renal calculi and demonstrate the utility of the novel IPC-UAS in improving outcomes of RIRS for 2-4 cm renal stones.

Pharmacological Modulation of Intrarenal Pressure in a Porcine Model Using a Novel Isoprenaline-Eluting Guidewire.

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.

Impact of Pre-Operative Ureteroscopy on Bladder Recurrence Following Nephroureterectomy for UTUC.

(1) Introduction: Diagnostic ureteroscopy (URS) is an important component in the workup of upper tract urothelial carcinoma (UTUC). Whether URS was associated with increased recurrence in the bladder was not fully concluded. The current study aimed to evaluate the implication of URS on the incidences of intravesical recurrence following radical nephroureterectomy (RNU) in non-metastatic UTUC patients without prior history of bladder cancer via multi-institutional data. (2) Patients and Methods: Data were obtained from the Clinical Research Office of the Endourology Society Urothelial Carcinomas of the Upper Tract (CROES-UTUC) registry, a prospective, multicentre database. Patients with non-metastatic UTUC treated with RNU were divided into two groups: those undergoing upfront RNU and those having diagnostic URS prior to RNU. Intravesical recurrence-free survival (IVRS) was the primary endpoint, evaluated through Kaplan-Meier analysis and multivariate Cox regression. Cases with adequate follow-up data were included. (3) Results: The analysis included 269 patients. Of these, 137 (50.9%) received upfront RNU and 132 (49.1%) received pre-RNU URS. The URS group exhibited an inferior 24-month IVRS compared to the upfront RNU group (HR = 1.705, 95% CI = 1.082-2.688; p = 0.020). Multivariate analysis confirmed URS as the only significant predictor of IVR (p = 0.019). Ureteric access sheath usage, flexible ureteroscopy, ureteric biopsy, retrograde contrast studies, and the duration of URS did not significantly affect IVRS. (4) Conclusions: Diagnostic URS prior to RNU was found to be associated with an increased risk of IVR in patients with UTUC. The risk was not significantly influenced by auxiliary procedures during URS. Physicians were advised to meticulously evaluate the necessity of diagnostic URS.

Intrarenal pressure and flow rate profile using LithoVue™ elite: impact of different irrigation systems and working channel instruments.

To report real-time IRP and FR while performing flexible ureteroscopy in porcine kidney model utilizing LithoVue™ Elite (Boston Scientific®) with different irrigation systems, including automated pumps. Using an ex-vivo model of porcine kidney, IRPs were measured with LithoVue Elite. Ureteroscopic settings (US) were tested with all permutations of irrigation methods (IM), working channel occupant (WCO), and ureteral access sheaths (UAS). IMs included: Single Action Pumping System (SAPS™, Boston Scientific), Thermedx FluidSmart™ (Stryker®), and ENDOMAT™ (Karl Storz®). Pumps were tested at 50, 100, and 150mmHg. WCOs included a 1.9Fr zero-tip basket, 200µm, and 365µm laser fibers. UASs utilized 11/13Fr and 12/14Fr 36cm. 84 different US were tested (252 experiments). ENDOMAT had higher IRP but the same FR as Thermedx at the same US for 50 and 100mmHg (p < 0.01). SAPS had higher IRP and FR than pumps in all US studies (p < 0.01). There was positive correlation between pressure set by the pump and both IRP and FR (rho > 0.9). As the diameter of the WCO increased, lower IRP and FR were observed with the pumps (p < 0.01). With SAPS, IRP was similar regardless of WCO, but FR was decreased with the increased diameter of WCO (p = 0.81 and p < 0.01, respectively). There was significantly higher IRP when using 11/13Fr UAS than 12/14Fr (p < 0.01). IRP was higher with SAPS than automated pumps. ENDOMAT showed higher IRP than Thermedx when under 150mmHg. IRP and FR increase with higher pump pressure and decrease with larger diameter WCO. Likewise, a larger UAS significantly reduced IRP.

The impact of siphoning effect on renal pelvis pressure during ureteroscopy using an in vitro kidney and ureter model.

To experimentally measure renal pelvis pressure (PRP) in an ureteroscopic model when applying a simple hydrodynamic principle, the siphoning effect. A 9.5Fr disposable ureteroscope was inserted into a silicone kidney-ureter model with its tip positioned at the renal pelvis. Irrigation was delivered through the ureteroscope at 100cm above the renal pelvis. A Y-shaped adapter was fitted onto the model's renal pelvis port, accommodating a pressure sensor and a 4 Fr ureteral access catheter (UAC) through each limb. The drainage flowrate through the UAC tip was measured for 60s each run. The distal tip of the UAC was placed at various heights below or above the center of the renal pelvis to create a siphoning effect. All trials were performed in triplicate for two lengths of 4Fr UACs: 100cm and 70cm (modified from 100cm). PRP was linearly dependent on the height difference from the center of the renal pelvis to the UAC tip for both tested UAC lengths. In our experimental setting, PRP can be reduced by 10 cmH20 simply by lowering the distal tip of a 4 Fr 70cm UAC positioned alongside the ureteroscope by 19.7cm. When using a 4 Fr 100cm UAC, PRP can drop 10 cmH20 by lowering the distal tip of the UAC 23.3cm below the level of the renal pelvis. Implementing the siphoning effect for managing PRP during ureteroscopy could potentially enhance safety and effectiveness.

Suction use in ureterorenoscopy: A systematic review and meta‐analysis of comparative studies

AbstractObjectivesUreterorenoscopy is seeing a bloom of technological advances, one of which is incorporating suction. The objective of this study is to systematically review existing literature regarding suction use in rigid and flexible ureterorenoscopy and perform meta‐analysis of studies comparing suction versus no suction ureteroscopy or mini percutaneous nephrolithotomy (PCNL).MethodsA literature search was performed (November 2023) in MEDLINE, Embase and Cochrane CENTRAL. Study protocol was registered at PROSPERO (CRD42023482360). Comparative studies (observational and randomized) were eligible for inclusion if they compared suction versus no suction group and reported at least one primary outcome of interest (stone‐free or complication rate).ResultsSixteen studies (5 randomized and 11 observational), analysing 1086 and 1109 patients in standard and suction groups, respectively, were included. Final stone‐free rates (SFRs), overall and infectious complications and length of hospital stay exhibited significant improvement when suction was used. When mini‐PCNL was compared with flexible ureterorenoscopy with suction, no differences were found in terms of stone‐free and infectious complications rates.ConclusionsUreterorenoscopy is a commonly performed endoscopic procedure for urolithiasis treatment, the success of which is defined by SFRs and complication rates. Application of suction via ureteral access sheaths, ureteral catheters or scopes may provide improved SFRs, reduced overall and infectious complication rates, along with a reduction in length of hospital stay. Further randomized studies are needed to validate these findings and standardize indications and protocols.

Tip bendable suction ureteral access sheath versus traditional sheath in retrograde intrarenal stone surgery: an international multicentre, randomized, parallel group, superiority study

Retrograde intrarenal surgery (RIRS) is the main treatments for upper urinary tract stones. The Ureteral Access Sheath (UAS) serves as a supplementary tool, facilitating direct kidney access during RIRS. High quality of evidence comparing tip bendable suction ureteral access sheath (S-UAS) with traditional UAS in RIRS for the treatment of renal and ureteral stones is lacking. The purpose of the study is to compare the efficacy and safety of S-UAS with traditional UAS in RIRS for the treatment of renal or ureteral stones ≤30mm. An international, multicenter, and superiority randomized controlled trial included 320 intention-to-treat patients across 8 medical centers in China, the Philippines, Malaysia and Turkey from August 2023 to February 2024. The inclusion criteria were patients ≥18 years old with renal or ureteral stones ≤30mm. RIRS was performed using either S-UAS or traditional UAS. The primary outcome was the immediately stone-free rate (SFR). Secondary outcomes included SFR 3 months after operation, operating time, hospital stay, auxiliary procedures, complications (using the Clavien-Dindo grading system), and improvement in the Quality of Life (QoL) score. Differences between proportions [risk difference (RD)]/means [mean difference (MD)] and 95% confidence intervals (CI) were presented. This study is registered at ClinicalTrials.gov: NCT05952635. The S-UAS group demonstrated a significantly higher immediately SFR (81.3% versus 49.4%; RD 31.9%; 95% CI 22.5%-41.7%; p=0.004) compared to the traditional UAS group, as determined by the one-side superiority test. Additionally, the S-UAS group exhibited a higher SFR at 3 months post-operation (87.5% versus 70.0%; RD 17.5%; 95% CI 8.7%-26.3%; p<0.001), lower postoperative fever rate (RD-11.9%; 95% CI-18.7% to-4.9%; p<0.001), reduced use of stone baskets (RD-70.6%; 95% CI-77.8% to-63.5%; p<0.001), and better QoL improvement (MD 7.25; 95% CI 2.21-12.29; p=0.005). No statistically significant differences were observed in operation time, hospital stay, or the need for second-stage RIRS. In RIRS for upper urinary tract stones ≤30mm, S-UAS exhibited superior performance compared to traditional UAS, demonstrating higher SFR, reduced postoperative fever rate, and improved QoL outcomes. S-UAS emerges as a prudent and advantageous alternative to traditional UAS for RIRS. National Natural Science Foundation of China and Guangdong Province, and Zhejiang Medicine and Health Program.

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

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

Development and Initial Evaluation of a Cost-Effective Force Sensor for Ureteroscopic Application.

Purpose: Retrograde intrarenal surgery is the gold-standard treatment for most kidney stones. During ureteroscopy, ureteral access sheath insertion at forces greater than 8.0 Newtons (N) risks high-grade ureteral injury. To monitor force, our institution utilizes a unique, Bluetooth-equipped device (i.e., the University of California-Irvine Force Sensor). Given the unique nature of the force sensor, we sought to develop an inexpensive and accessible force sensor based on Boyle's law and the specific amount of force required to compress an occluded 1.0 mL syringe. Materials and Methods: We evaluated three brands of 1.0 mL syringes. After setting the plunger at 1.0 mL, the syringe was occluded, and the syringe plunger was compressed. The syringe volume was recorded when the applied force on the plunger reached 4.0 N, 6.0 N, and 8.0 N. Multiple trials were performed to assess reliability and reproducibility. A method for applying this clinically was also developed. Results: The precise force thresholds identified for a 1.0 mL Luer-Lok™ Syringe (Becton Dickinson, Franklin Lakes, NJ) were 0.30 mL for 4.00 N, 0.20 mL for 6.00 N, and 0.15 mL for 8.00 N. The 1.0 mL Tuberculin Syringe and 1.0 mL Luer Slip Syringe were less precise, but compression from 1.0 to 0.40 mL, 0.25 mL, and 0.20 mL corresponded to force sensor readings that did not exceed 4.00 N, 6.00 N, and 8.00 N, respectively. Conclusions: Based on volume changes, 4.00 N, 6.00 N, and 8.00 N of force can be reliably and reproducibly achieved using an occluded 1.0 mL syringe.

Could radiological parameters help to predict the failure of ureteral access sheath placement

To identify the radiological parameters which may help to predict the success of ureteral access sheath (UAS) placement during retrograde intrarenal surgery (RIRS).The study included 49 patients in whom failure ureteral access sheath placement in RIRS and 49 control group patients who were successfully placement between January 2023 and December 2023. The age, gender, body mass index (BMI), non-contrast computed tomography (NCCT), and kidney ureter bladder (KUB) radiographs were compared between the two groups. Measurements of the anteroposterior (ap) diameter of the pelvic inlet, anteroposterior diameter of the pelvic outlet, interspinous distance diameter were taken from non-contrast computed tomography (NCCT), while pelvic anteroposterior diameter and pelvic lateral diameter were measured from kidney ureter bladder (KUB) radiography. There were no significant differences between the groups in age, gender, body mass index, ap pelvic inlet diameter, ap pelvic outlet, and interspinous distance diameter. However, a statistically significant difference was found between the pelvic ap diameter and pelvic lateral diameter values measured on the KUB radiography. The values for pelvic ap diameter and pelvic lateral diameter measured in the KUB radiographs can be used to predict the likelihood of UAS passage during RIRC procedures. However, further studies with larger patient groups are needed to establish a cut-off value.

Preoperative α1-Blockers Impact on Outcomes of Patients Undergoing Ureteroscopy with Ureteral Access Sheaths: A Systematic Review and Meta-Analysis.

Introduction: The use of a ureteral access sheath (UAS) during ureteroscopy (URS) has been associated with the risk for ureteral injuries. Preoperative administration of α1-blockers presents a potential mitigator of such lesions by inducing ureteral relaxation, which may also contribute to improving other surgical outcomes. Methods: A comprehensive literature search was conducted across MEDLINE, Embase, and Cochrane databases for studies comparing preoperative α1-blockers administration vs its non-use in adult patients without pre-stenting undergoing URS. Binary outcomes were evaluated using risk ratios (RRs) and odds ratios (ORs) with 95% confidence intervals (CIs). Heterogeneity was measured with the Cochran's Q test, I2 statistics, and prediction intervals (PIs). A DerSimonian and Laird random-effects model was utilized for all outcomes. Results: Eleven studies encompassing 1074 patients undergoing URS were included, of whom 522 (48.60%) received α1-blockers before the procedure. Preoperative α1-blockers were associated with a reduction in significant ureteral injuries (RR 0.30; 95% CI 0.17-0.53; I2 = 6%; PI 0.10-0.88) and an increase in mean successful UAS insertion (OR 2.14; 95% CI 1.08-4.23; I2 = 23%; PI 0.51-8.93). In patients undergoing exclusively ureteroscopy lithotripsy (URSL), the medications also reduced total complications (RR 0.62; 95% CI 0.46-0.84; I2 = 0%) and complications graded Clavien-Dindo III or higher (RR 0.16; 95% CI 0.04-0.69; I2 = 0%), but no significant difference between groups was found in the stone-free rate (RR 1.10; 95% CI 0.86-1.40; I2 = 91%; PI 0.47-2.59). Conclusion: Preoperative α1-blockers were linked to a decrease in significant ureteral injuries with UAS use and fewer complications during URSL procedures. However, their impact on the successful insertion of a UAS remains uncertain. Consideration of administering preoperative α1-blockers in non-stented adult patients undergoing URS with UAS is advisable.

Monitoring Intrarenal temperature changes during Ho: YAG laser lithotripsy in patients undergoing retrograde intrarenal surgery: a novel pilot study.

Ho: YAG laser lithotripsy is widely used for urinary stone treatment, but concerns persist regarding its thermal effects on renal tissues. This study aimed to monitor intrarenal temperature changes during kidney stone treatment using retrograde intrarenal surgery with Ho: YAG laser. Fifteen patients were enrolled. Various laser power settings (0.8J/10 Hz, 1.2J/12 Hz) and irrigation modes (10cc/min, 15cc/min, 20cc/min, gravity irrigation, and manual pump irrigation) were used. A sterile thermal probe was attached to a flexible ureterorenoscope and delivered into the calyceal system via the ureteral access sheath. Temperature changes were recorded with a T-type thermal probe with ± 0.1°C accuracy. Laser power significantly influenced mean temperature, with a 4.981°C difference between 14W and 8W laser power (p < 0.001). The mean temperature was 2.075°C higher with gravity irrigation and 2.828°C lower with manual pump irrigation (p = 0.038 and p = 0.005, respectively). Body mass index, laser power, irrigation model, and operator duty cycle explained 49.5% of mean temperature variability (Adj. R2 = 0.495). Laser power and operator duty cycle positively impacted mean temperature, while body mass index and specific irrigation models affected it negatively. Laser power and irrigation rate are critical for intrarenal temperature during Ho: YAG laser lithotripsy. Optimal settings and irrigation strategies are vital for minimizing thermal injury risk. This study underscores the need for ongoing research to understand and mitigate thermal effects during laser lithotripsy.

Intrarenal pressure with hand-pump or pressurized-bag irrigation: randomized clinical trial at retrograde intrarenal surgery.

The aim was to ascertain the impact of irrigation technique on human intrarenal pressure during retrograde intrarenal surgery. A parallel randomized trial recruited patients across three hospital sites. Patients undergoing retrograde intrarenal surgery for renal stone treatment with an 11/13-Fr ureteral access sheath were allocated randomly to 100 mmHg pressurized-bag (PB) or manual hand-pump (HP) irrigation. The primary outcome was mean procedural intrarenal pressure. Secondary outcomes included maximum intrarenal pressure, variance, visualization, HP force of usage, procedure duration, stone clearance, and clinical outcomes. Live intrarenal pressure monitoring was performed using a COMETTMII pressure guidewire, deployed cystoscopically to the renal pelvis. The operating team was blinded to the intrarenal pressure. Thirty-eight patients were randomized between July and November 2023 (trial closure). The final analysis included 34 patients (PB 16; HP 18). Compared with PB irrigation, HP irrigation resulted in significantly higher mean intrarenal pressure (mean(s.d.) 62.29(27.45) versus 38.16(16.84) mmHg; 95% c.i. for difference in means (MD) 7.97 to 40.29 mmHg; P = 0.005) and maximum intrarenal pressure (192.71(106.23) versus 68.04(24.16) mmHg; 95% c.i. for MD 70.76 to 178.59 mmHg; P < 0.001), along with greater variance in intrarenal pressure (log transformed) (6.23(1.59) versus 4.60(1.30); 95% c.i. for MD 0.62 to 2.66; P = 0.001). Surgeon satisfaction with procedural vision reported on a scale of 10 was higher with PB compared with HP irrigation (mean(s.d.) 8.75(0.58) versus 6.28(1.27); 95% c.i. for MD 1.79 to 3.16; P < 0.001). Subjective HP usage force did not correlate significantly with transmitted intrarenal pressure (Pearson R = -0.15, P = 0.57). One patient (HP arm) developed urosepsis. Manual HP irrigation resulted in higher and more fluctuant intrarenal pressure trace (with inferior visual clarity) than 100-mmHg PB irrigation. osf.io/jmg2h (https://osf.io/).

Factors affecting the success and perioperative complications of retrograde intrarenal surgery: a retrospective clinical analysis

Background and objective: Many factors are presumed to have an impact on the results of retrograde intra renal surgery. In the current study, our objective was to actuate the possible factors influencing the stone-free rates and complications post lone-session retrograde intrarenal surgery for renal calculi. Stone-free rates Methods: Overall 200 patients who undergone retrograde intra renal surgery between January 2019 and March 2022 were evaluated, retrospectively. Success was decided if there were no residual fragments on pain X-ray and ultrasonography. Patient demographics, stone characteristics, perioperative data were assessed and analyzed to actuate predictive factors influencing stone-free rates and perioperative morbidities. Results: Two hundred patients with a mean age of 41.12±14.37 years were evaluated. The mean stone size was 1.815 ± 2.107 millimeters (mm), mean stone density was 969.63 ± 345.307 Hounsfield unit. The immediate SFR was (76.8±0.42) while the final SFR (single session) was 87.9±0.46. Thirty-seven patients (18.5%) developed complications, the preponderance of them 86% were minor complications (Clavien grade I and II). In multivariate regression analysis, multiple renal stones and ureteral access sheath use were constitute to be statically significant predictors of stone-free status. Moreover, multivariate regression analysis revealed that operative time, lasing time and stone opacity stones were statistically significant factors influencing perioperative complications. Conclusion: Success rates inversely related to stones number and ureteral access sheath usage. While prolonged operation time, lasing time, and higher stone density could be a more reliable predictor of perioperative complication development.

Design and Validation of a Novel 3D-Printed Retrograde Intrarenal Surgery Trainer

ObjectivesTo report on the design of a novel 3D-printed retrograde intrarenal surgery (RIRS) benchtop trainer and detail its validation against real-life experiences. MethodsDigital Imaging and Communications in Medicine (DICOM) files of two patients with normal computed tomography of the kidney and bladder were converted into stereolithography files to create 3D triangular mesh models. These images were further refined using Autodesk Meshmixer. These 3D models were fabricated through additive manufacturing, a process commonly known as 3D printing and assembled in a polypropylene case. After development, the model was validated by 40 experienced urologists and urology residents in their final year of training. They were asked to rate the components of the simulation using a nine-point questionnaire. ResultsThe model’s value in understanding the principles of RIRS and simulating contextual anatomy had mean scores of 9.43 (standard deviation [SD] = 0.74) and 9.21 (SD = 1.03), respectively. Mean scores for specific steps in RIRS were 8.07 (SD 1.47) for cannulating the ureteric orifice, 8.61 (SD 1.24) for inserting the ureteric access sheath, 9.29 (SD 0.97) for performing a renoscopy and evaluating all the calyces, 9.46 (SD 0.87) for laser lithotripsy, and 9.17 (SD 0.94) for manual stone retrieval. Participants scored the model with a mean score of 9.04 (SD 0.87) regarding realism and a mean score of 9.18 (SD 0.89) when evaluating its ability to enhance a trainee’s confidence in RIRS. ConclusionsThe model performed well for all components of RIRS. This model allows high fidelity of the simulation, and is cost-effective, portable, durable, reusable, and compatible with standard ureteroscopes.

Endoscopic combined intrarenal surgery versus percutaneuos nephrolithotomy for complex pediatric stone disease: A comparative analysis of efficacy and safety

INTRODUCTIONDecision-making for complex pediatric urinary system stone disease is still a challenge for pediatric urologists. The interest in supine percutaneous nephrolithotomy (PCNL) is increasing among centers to achieve high surgical success rates with less morbidity. Despite advanced retrograde intrarenal surgery armamentarium, percutaneous approaches remain the first-line surgical treatment modality for >2 cm and complex renal stones. There are no comparative studies yet in the literature for pediatric endoscopic combined intrarenal surgery (ECIRS) OBJECTIVEIn this study, we aimed to contribute to the literature by evaluating the safety and efficacy of ECIRS by comparing it with PCNL. STUDY DESIGNPatients under 18 years of age who underwent PCNL and ECIRS for urinary tract stone disease at our Pediatric Urology department between 2012 and 2024 were included. Preoperative (demographic characteristics, stone characteristics, biochemical parameters), perioperative (duration of surgery, number of accesses, lasing and fluoroscopy times, endoscopic and fluoroscopic stone-free rates) and postoperative (hospital stay, urinary tract infection, complication and radiological stone-free rates) parameters were retrospectively evaluated. RESULTSA total of 68 children [28 (41%) girls and 40 (59%) boys] aged 5 (0-17) years were included in the study. ECIRS was performed in 19 (28%), supine in 28 (41%) and prone PCNL in 21 (30%) patients. Age (p = 0.029), Guy's stone score (p<0.001), S.T.O.N.E. (p<0.001), and Seoul National University Renal Stone Complexity (S-ReSC) scores (p=0.001) for preoperative parameters were found to be higher in ECIRS group over both PCNL methods (Summary Table). However, Clinical Research Office of the Endourological Society (CROES) score was seen lower for ECIRS group patients compared to other groups (p=0.028).Surgery time (in favor of supine over prone PCNL), fluoroscopy time (in favor of ECIRS and Supine PCNL over Prone PCNL), preferred laser type (prone PCNL group was mostly performed with holmium laser, whereas other groups were balanced between Holmium and Thulium Fiber Laser) and exit strategy (the preferred exit strategy was DJ Stent in most of the ECIRS patients, whereas nephrostomy tube was used in some of the PCNL group) showed significant difference among the groups as perioperative parameters (p=0.042, <0.001, <0.001, <0.001, respectively). Surgery time was lower for supine PCNL compared to prone PCNL. For postoperative parameters, stone-free rates, complication rates and urinary tract infections were similar between the 3 groups, while a difference was detected in terms of length of hospital stay in favor of ECIRS over both supine and prone PCNL (p = 0.006). DISCUSSIONThe current trial suggests that stone-free and complication rates of ECIRS and supine PCNL were similar in the pediatric complex stone patients. Although, the stones in the ECIRS group we found to be more complex. Also, ECIRS was superior to PCNL in terms of fluoroscopy exposure and hospital stay. CONCLUSIONWith the widespread use of new generation ureteral access sheaths and flexible ureterorenoscopes, ECIRS may have an important role in treatment of complex pediatric kidney stones.

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

ObjectiveTo evaluate the safety and efficacy of rigid ureteroscopic lithotripsy with a pressure-controlling ureteral access sheath (PC-UAS) for complex steinstrasse.MethodsThirty-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.ResultsAmong 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.ConclusionsRigid 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.