Glenn M. Preminger

Purpose: We report the first multicenter, prospective, randomized noninferiority controlled trial of steerable ureteroscopic renal evacuation (SURE) for nephrolithiasis treatment. Materials and Methods: Candidates for laser lithotripsy ≥18 years with ≥1 renal stone ≥7 mm and 7–20 mm stone burden were randomized 1:1 SURE vs ureteroscopy (URS). SURE was performed using the CVAC Aspiration System, a novel steerable irrigation–aspiration catheter. The primary efficacy end point was noninferiority in stone-free rate (SFR) based on zero residual fragments (RFs) 30 days postprocedure on noncontrast computed tomography. Secondary end points were superiority tests, stone clearance (percent stone volume reduction), residual stone volume (RSV), SFR (no RF >2 mm), and SFR (no RF >4 mm) 30 days postprocedure. Results: Of the subjects, 123 were randomized and 101 qualified for efficacy analysis (SURE 46 vs URS 55). Despite randomization, baseline URS stone volume was higher (SURE 485.0 ± 432.5 mm ³ vs URS 713.3 ± 558.5 mm ³ ). The primary noninferiority end point was achieved (SURE SFR 48% vs URS SFR 49%, p = 0.027, −1.3% [90% confidence interval; −18%, 15%]). Stone clearance was significantly higher for SURE vs URS subjects (SURE 96.9 ± 5.6% vs URS 92.9 ± 11.6%, p = 0.036); RSV was significantly lower (SURE 14.3 ± 3 0.9 mm ³ vs URS 70.2 ± 144.9 mm ³ , p = 0.012). SURE stone clearance and RSV were independent of baseline stone volume, but for URS degraded with increasing baseline stone volume. Safety was comparable between groups. Conclusions: SFR for SURE subjects was noninferior compared with URS subjects; stone clearance and RSV were significantly better with SURE, independent of baseline stone volume.

Purpose: To define a peak force of insertion (PFOI) threshold for ureteral damage during ureteral access sheath (UAS) placement on an experimental ureteral orifice model. Methods: A specially designed water tank using 2 laparoscopic 5 mm ports and 2 different size (10 Fr and 8 Fr) sealing cap adaptors (SCA) as ureteral orifices was used to perform the test. A 10–12 Fr UAS was fixed to a load cell and the force of insertion (FOI) was continuously recorded with a digital force gauge.13 experts in the field of endourology who participated performed 3 UAS insertions. The FOI was recorded initially with 10 Fr followed by 8 Fr SCA. On the final insertion, the orifice was obstructed, leaving a 5 cm length to insert the UAS. The experts were asked to “Stop at the point they anticipate ureteral damage, and they would not proceed in real life”. Results: Using 10 Fr SCA the PFOI was 2.12 ± 0.58 Newton (N) (range:1.48–3.48) while 8 Fr SCA showed a PFOI 5.76 ± 0.96 N (range:4.05–7.35). Six of the experts, said they would stop proceeding when they reached above 5.1 N. Three experts had PFOI < 5.1 N and the other 4 stated they would go with PFOIs of 5.88, 6.16, 6.69 and 7.35 N when using SCA of 8 Fr.The highest load they would stop proceeding had a PFOI of 6.09 ± 1.87 N (range: 2.53–10.74). Conclusion: The PFOI threshold for ureteral damage inserting UAS of the experts is variable. Although FOI is a subjective perception, experience suggests that ureteral injury may occur at an average of 6.05 N perceived by surgeons’ tactile feedback. In-vivo measurement of UAS PFOI may confirm a threshold.

Introduction. The emergence of new scientific and clinical evidence on the use of retrograde intrarenal surgery (RIRS) for the management of kidney stones has prompted periodic systematisation, analysis, and evaluation of outcomes to standardise its application and determine future directions for research and development.Objective. To present the Russian adaptation of a guideline on retrograde intrarenal surgery from the International Urolithiasis Alliance guideline series to provide a theoretical basis for urologists performing RIRS.Materials & Methods. A systematic review was conducted on the RIRS-associated publications available in the PubMed database to prepare a set of recommendations during the period from 1 January 1964 until 1 October 2021. The recommendations were evaluated using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) system, which classifies, evaluates, develops, and examines recommendations. The modified Oxford Centre for Evidence-Based Medicine's (OCEBM) system for categorising the level of evidence and relevant comments have been applied to assess the strength of the conclusions.Results. The research team conducted a comprehensive analysis of 36 published clinical guidelines on the following topics: 1. Indications and Contraindications 2. Preoperative Imaging 3. Preoperative Ureteral Stenting 4. Preoperative Medications 5. Perioperative Use of Antibiotics 6. Use of Antithrombotic Therapy 7. Anesthesia Issues 8. Intraoperative Positioning 9. Equipment 10. Complications.Conclusion. A series of recommendations for RIRS, offered here should help provide safe and effective performance of RIRS.

Objective: Low energy and high frequency settings are used in stone dusting for holmium lasers. Such settings may not be optimal for thulium fiber laser (TFL). With the seemingly endless combination of settings, we aim to provide guidance to the practicing urologists and assess the efficiency of the TFL platform in an automated in vitro “dusting model.” Materials/Methods: Three experimental setups were designed to investigate stone dusting produced by an IPG Photonics TLR-50 W TFL system using 200 μm fiber and soft BegoStone phantoms. The most popular 10 and 20 W dusting settings among endourologist familiar with TFL were evaluated. We directly compared short pulse (SP) vs long pulse (LP) mode using various combinations of pulse energy (E _p ) and pulse frequency (F). Thereafter, we tested the 10 and 20 W settings and compared them among each other to elucidate the most efficient settings at each power. Treatments were performed under the same total laser energy delivered to the stone at four different standoff distances (SDs) with a clinically relevant scanning speed of either 1 or 2 mm/sec. Ablation volumes were quantified by optical coherence tomography to assess stone dusting efficiency. Fragment size after ablation at different pulse energies was evaluated by sieving and evaluating under a microscope after treatment. Results: Overall, SP provided greater ablation volume when compared with LP. Our dusting efficiency model demonstrated that the maximum stone ablation was achieved at the combination of high energy/low frequency settings ( p < 0.005) and at a SD of 0.2 mm. At all tested pulse energies, no stone phantoms were broken into fragments >1 mm. Conclusions: During stone dusting with TFL, SP offers superior ablation to LP settings. Optimal dusting at clinically relevant scanning speeds of 1 and 2 mm/sec occurs at high energy/low frequency settings. Thulium lithotripsy with high E _p does not result in increased fragment size.

Michael ZD, et al. World J Mens Health. 2022 Aug;40:e60. https://doi.org/10.5534/wjmh.220068

Introduction: Manipulation of Holmium:Yttrium–Aluminum–Garnet laser parameters such as pulse energy (PE), frequency, and duration can impact laser lithotripsy ablation efficiency. In 2017, Lumenis introduced Moses™ Technology, which uses pulse modulation to enhance the delivery of energy from fiber to stone as well as to minimize stone retropulsion. Since the introduction of Moses Technology, other companies have brought additional pulse modulation concepts to market. The purpose of this in vitro study is to compare the pulse characteristics and stone ablation efficiency of Lumenis Moses Technology with Quanta's Vapor Tunnel™. Materials and Methods: Submerged BegoStone phantoms were systematically ablated using either the Lumenis Moses Pulse 120H or the Quanta Litho 100 clinical laser system. Two PEs (0.4 and 1 J), three fiber-stone standoff distances (SDs) (0.5, 1, 2 mm), and all available pulse duration and modulation modes for each laser were tested in combination. Fiber speed was adjusted to scan across the stone surface at either 1 or 10 pulses/mm to form single pulse craters or an ablation trough, respectively. Volumes of single craters and 1 mm trough segments were imaged and quantified using optical coherence tomography. Results: Ablation volumes decreased with decreasing PE and increasing SD. Statistically significant variability was seen between pulse types (PT) at every tested parameter set. Among pulse modulation modes, Moses Distance (MD) was superior at 0.5 mm in all testing and at 2 mm in trough testing. Vapor Tunnel (VT) was superior in 2 mm single crater testing. All modulated pulses performed similarly at 1 mm. Conclusions: In this benchtop model of laser lithotripsy, stone ablation was significantly impacted by PT. MD demonstrated superior or noninferior stone ablation at most tested parameters. VT maintained its efficacy the best as SD increased. Future work should focus on the mechanistic differences of these modes relative to other traditional laser pulse modes.

Introduction: Office cystoscopy is one of the most frequently performed procedures by a urologist. However, single-use cystoscopes remain quite undeveloped. Ambu ^® has developed single-use broncoscopes, rhinolaryngoscopes, and duodenoscopes. Recently, they released a single-use cystoscope. In this study, we performed a benchtop and an initial clinical assessment of the Ambu aScope™ (4) Cysto (aS4C) single-use cystoscope. Materials and Methods: Ten new, never-used aS4C single-use cystoscopes were assessed for optical performance, maximal tip flexion, and irrigation flow rate with empty working channel, 365 μm laser fiber, 0.035 in hydrophilic-tipped wire, 1.9F nitinol basket, and a 1.8 mm flexible stent grasper. All cystoscopes were then fully flexed 25 times in each direction, and maximal flexion angles were remeasured with and without instruments. Optical resolution, distortion, and depth of field were measured and compared with our reusable digital flexible cystoscopes. Assessment of clinical use was performed for inpatient bedside procedures using a Likert feedback survey and the NASA Task Load Index. Results: Maximal upward flexion exceeded 200° and 160° for all working instruments in upward and downward flexion. Downward flexion demonstrated different flexion between instrument groups in pre- and postcycling ( p < 0.001). There was no clinical difference between the pre- and postcycling flexion. Flow rate decreased with increasing working instrument size ( p < 0.001). The Olympus HD cystoscope resolution was superior at 3 and 5 mm distance, but not at other distances. The Ambu scope was superior to the Olympus SD scope at all distances except 3 mm. The aS4C had higher Likert scale survey scores for clinical use. Conclusions: The new Ambu single-use cystoscope demonstrates good flexion across instruments and comparable optics with reusable cystoscopes. In addition, initial inpatient bedside use of the aS4C and Monitor system compares favorably with the Olympus reusable cystoscope. Further testing in clinical scenarios such as hematuria, urothelial carcinoma, and operative endoscopy is warranted.

Introduction: A novel single-use flexible ureteroscope promises the optical characteristics and maneuverability of a reusable fourth-generation flexible ureteroscope. In this study, the LithoVue Single-Use Digital flexible ureteroscope was directly compared with contemporary reusable flexible ureteroscopes, with regard to optics, deflection, and irrigation flow. Methods: Three flexible ureteroscopes such as the LithoVue (Single Use; Boston Scientific), Flex-Xc (Karl Storz, Germany), and Cobra (Richard Wolf, Germany) were assessed in vitro for image resolution, distortion, color representation, grayscale imaging, field of view, and depth of field. Ureteroscope deflection was tested with an empty channel followed by placement of a 200 μm laser fiber and a 1.9F wire basket, a 2.0F nanoelectric pulse lithotripsy (NPL) probe, and a 2.4F NPL probe. Ureteroscope irrigation flow was measured using normal saline at 100 cm, with an empty channel followed by a 200 μm laser fiber, a 1.9F wire basket and a 2.0F NPL probe. Results: The LithoVue showed the largest field of view, with excellent resolution, image distortion, and depth of field. No substantial difference was demonstrated in color reproducibility or in the discernment of grayscales between ureteroscopes. The LithoVue maintained full deflection ability with all instruments in the working channel, although the Flex-Xc and Cobra ureteroscopes showed loss of deflection ranging from 2° to 27°, depending on the instrument placed. With an empty channel, the LithoVue showed an absolute flow rate similar to the Flex-Xc ureteroscope (p = 0.003). It maintained better flow with instruments in the channel than the Flex-Xc ureteroscope. The Cobra ureteroscope has a separate 3.3F instrument channel, keeping flow rates the same with instrument insertion. Conclusion: The LithoVue Single-Use Digital ureteroscope has comparable optical capabilities, deflection, and flow, making it a viable alternative to standard reusable fourth-generation flexible digital and fiberoptic ureteroscopes.