In vitro investigation of stone ablation efficiency, char formation, spark generation, and damage mechanism produced by thulium fiber laser.

To investigate stone ablation characteristics of thulium fiber laser (TFL), BegoStone phantoms were spot-treated in water at various fiber tip-to-stone standoff distances (SDs, 0.5 ~ 2 mm) over a broad range of pulse energy (Ep, 0.2 ~ 2 J), frequency (F, 5 ~ 150 Hz), and power (P, 10 ~ 30 W) settings. In general, the ablation speed (mm3/s) in BegoStone decreased with SD and increased with Ep, reaching a peak around 0.8 ~ 1.0 J. Additional experiments with calcium phosphate (CaP), uric acid (UA), and calcium oxalate monohydrate (COM) stones were conducted under two distinctly different settings: 0.2 J/100 Hz and 0.8 J/12 Hz. The concomitant bubble dynamics, spark generation and pressure transients were analyzed. Higher ablation speeds were consistently produced at 0.8 J/12 Hz than at 0.2 J/100 Hz, with CaP stones most difficult yet COM and UA stones easier to ablate. Charring was mostly observed in CaP stones at 0.2 J/100 Hz, accompanied by strong spark-generation, explosive combustion, and diminished pressure transients, but not at 0.8 J/12 Hz. By treating stones in parallel fiber orientation and leveraging the proximity effect of a ureteroscope, the contribution of bubble collapse to stone ablation was found to be substantial (16% ~ 59%) at 0.8 J/12 Hz, but not at 0.2 J/100 Hz. Overall, TFL ablation efficiency is significantly better at high Ep/low F setting, attributable to increased cavitation damage with less char formation.

Rural For-Profit Hospitals Are Associated With Higher Commercial Prices for 3 Common Urological Procedures.

INTRODUCTION: Rural patients lack access to urological services, and high local prices may dissuade underinsured patients from surgery. We sought to describe commercially insured prices for 3 urological procedures at rural vs metropolitan and for-profit vs nonprofit hospitals. METHODS: A cross-sectional analysis of commercially insured prices from the Turquoise Health Transparency data set was performed for ureteroscopy with laser lithotripsy, transurethral resection of bladder tumor, and transurethral resection of prostate. Hospital characteristics were linked using the Centers for Medicare and Medicaid Services Healthcare Cost Reporting Information System. Linear modeling analyzed median hospital price and its association with hospital characteristics. RESULTS: Overall, 1,532 hospitals reported urological prices in Turquoise. Median prices for each procedure were higher at rural for-profits (ureteroscopy $16,522, transurethral resection of bladder tumor $5,393, transurethral resection of prostate $9,999) vs rural nonprofits (ureteroscopy $4,512, transurethral resection of bladder tumor $2,788, transurethral resection of prostate $3,881) and metropolitan for-profits (ureteroscopy $5,411, transurethral resection of bladder tumor $3,420, transurethral resection of prostate $4,874). Rural for-profit status was independently associated with 160% higher price for ureteroscopy (relative cost ratio 2.60, P < .001), 50% higher for transurethral resection of bladder tumor (relative cost ratio 1.50, P = .002), and 113% higher for transurethral resection of prostate (relative cost ratio 2.13, P < .001). CONCLUSIONS: Prices are higher for 3 common urological surgeries at rural for-profit hospitals. Differential pricing may contribute to disparities for underinsured rural residents who lack access to nonprofit facilities. Interventions that facilitate transportation and price shopping may improve access to affordable urological care.

Advanced chronic kidney disease; A comparison between nephroureterectomy and nephron-sparing surgery for upper tract urothelial carcinoma.

PURPOSE: Renal function outcomes between radical nephroureterectomy (RNU) and nephron-sparing surgery (NSS) for upper tract urothelial carcinoma (UTUC) patients are not well established. We sought to compare the incidence and factors associated with development of advanced chronic kidney disease (CKD) between RNU and NSS and examine the role of acute kidney injury (AKI) on renal function outcomes. METHODS: We retrospectively analyzed an institutional database for patients who underwent either RNU or NSS for UTUC. Cumulative incidence of postoperative advanced CKD, defined as eGFR < 30 ml/min/1.73 m2, was compared between groups. Fine-Gray competing risk regression was used to identify predictors of advanced CKD. Locally weight scatterplot smoothing was used to assess postoperative eGFR trends. AKI events were counted, staged, and assessed for influence of progression to advanced CKD. RESULTS: Four hundred and twenty-six patients were included in analysis, with a median follow up of 6.68 years (IQR 3.4-12.2). Median preoperative eGFR was similar between the groups (NSS: 68 ml/min/1.73 m2, RNU: 65 ml/min/1.73 m2,P = 0.220). Cumulative incidence of advanced CKD was significantly lower in the NSS cohort (P = 0.009). Factors associated with advanced CKD included age, diabetes, recurrent AKI and RNU. Percent of patients with an AKI event differed between the groups (51.5% NSS, 72.7% RNU, P = <0.001), there was no between group difference in percentage of patients with recurrent AKI (25.6% NSS, 25.9% RNU, P =1). CONCLUSION: NSS provides a renal function benefit in UTUC. AKI is common among UTUC patients and recurrent AKI is a risk factor for development of advanced CKD.

Comparison of Different Pulse Modulation Modes for Holmium:Yttrium-Aluminum-Garnet Laser Lithotripsy Ablation in a Benchtop Model.

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.

Evolution of Single-Use Urologic Endoscopy: Benchtop and Initial Clinical Assessment of a New Single-Use Flexible Cystoscope.

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.

Benchtop Assessment of a New Single-Use Flexible Ureteroscope.

Introduction: Single-use flexible ureteroscopes are an increasingly popular alternative to reusable ureteroscopes. In this study, we performed a benchtop examination of the physical and optical properties of the new Dornier Axis™ (Webling, Germany) single-use ureteroscope. Methods: Ten new, never-used Dornier Axis ureteroscopes were assessed for optical performance, maximal tip deflection, and irrigation flow rate with an empty working channel and with insertion of 200 and 365 µm laser fibers, and a 1.9F nitinol basket. All ureteroscopes were then fully deflected 100 times in each direction, and maximal deflection angles were re-measured with and without instruments in the working channel. All measurements were performed in duplicate. In vitro optical testing for resolution, image distortion, and depth of field was performed and compared vs the LithoVue™ (Boston Scientific, Marlborough, MA) single-use ureteroscope. Statistical analyses using paired Wilcoxon rank-sum tests and Kruskal-Wallis multiple-group comparison tests were performed in R. Results: Median maximal deflection angles exceeded 300° in both directions before and after 100 full deflection cycles for all groups except the 365 µm laser fiber group. After 100 deflection cycles, there was no change in the majority of working instruments, except a decrease in upward flexion with an empty channel and 200 µm Moses™ laser fiber, and downward flexion with 200 µm Flexiva™ laser fiber (all <10°). After excluding the 365 µm fiber, there was no difference in multi-group comparison for upward and downward flexion pre- and post-cycling. Median flow rate through an empty channel was 48.0 mL/min, and it decreased significantly with all used instruments (p < 0.001). Compared with the LithoVue, the Axis demonstrated superior resolution at all tested distances and less distortion. Conclusions: The new Dornier Axis single-use ureteroscope demonstrates excellent tip deflection, which remains unchanged after 100 manual flexions in each direction. The Axis also demonstrates superior optical performance compared with the LithoVue in benchtop testing.

Evaluation of a Novel Single-Use Flexible Ureteroscope.

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.

New devices for kidney stone management.

PURPOSE OF REVIEW: The purpose of this review is to summarize recent developments in the array of devices which are commonly used by urologists in the surgical management of kidney stones. To accomplish this goal, an extensive review of recent endourology literature, conference abstracts, and publicly available documents from manufacturers and the United States Food and Drug Administration was collected and reviewed. RECENT FINDINGS: Recent developments in the holmium:yttrium-aluminum-garnet (Ho:YAG) laser lithotripsy include the introduction of pulse modulation. This technique delivers the laser energy in an asymmetric manner such that an initial bubble is created (the 'Moses effect') through which the remainder of the energy can then travel through without being absorbed by surrounding water. Even more novel is the thulium fiber laser, which is produced in a fundamentally different way than traditional Ho:YAG lasers and is not yet available for clinical use. Finally, novel mechanical lithotrites which effectively combine ultrasonic energy, ballistic energy, and suction capability appear to be highly effective for stone clearance in recent benchtop and clinical studies. SUMMARY: With the introduction of both new modifications of time-tested technologies as well as completely novel modalities, the practicing urologist's armamentarium of devices for the surgical management of kidney stones continues to grow. As the popularity of 'mini' procedures continues to grow, the adaptability of these technologies to these procedures will be critical to maintain maximum relevance.

Low Dose Fluoroscopy During Ureteroscopy Does Not Compromise Surgical Outcomes.

Objective: To evaluate whether reducing the dose of fluoroscopy to » of standard dose during unilateral ureteroscopy for ureteral stone treatment would impact in a reduction of total radiation emitted and whether this strategy would impact operation time, stone-free rate, and complication rate. Methods: From August 2016 to August 2017, patients over 18 years submitted to ureteroscopy for ureteral stone between 5 and 20 mm were prospectively randomized for » dose reduction or standard dose fluoroscopy. Patients with abnormal urinary anatomy such as horseshoe kidney, pelvic kidney, or duplex system were excluded from the study. Results: Ninety-four patients were enrolled. The fluoroscopic dose reduction strategy to » of the standard dose was able to significantly reduce the cumulative radiation emitted by C-arm fluoroscopy and the dose area product (3.6 ± 4.5 mGy vs 16.2 ± 19.3 mGy, p = 0.0001 and 0.23 ± 0.52 mcGycm2vs 1.15 ± 2.74 mcGycm2, p = 0.02, respectively). Fluoroscopy time was similar between groups (74.5 ± 84.8 seconds vs 88.3 ± 90 seconds, p = 0.44). There was no need to increase the fluoroscopy dose during any of the procedures. Surgical outcomes were not affected by fluoroscopic dose reduction strategy. Conclusion: Low dose fluoroscopy reduces the emitted radiation during ureteroscopy without compromising surgical outcomes.

Avoiding a Lemon: Performance Consistency of Single-Use Ureteroscopes.

INTRODUCTION AND OBJECTIVES: Single-use flexible ureteroscopes are increasingly popular because of high repair costs of reusable ureteroscopes. As new single-use ureteroscopes enter the market, the consistency of performance of these devices has been questioned. Our objective was to compare two single-use ureteroscopes: the Pusen PU3022a (Zhuhai Pusen) and the LithoVue (Boston Scientific) with emphasis on physical and optical performance consistency. METHODS: Ten LithoVue and 10 Pusen ureteroscopes were evaluated in never-used condition. The following parameters were recorded: maximal tip deflection with an empty working channel, 200 µm laser fiber, and 1.9F basket; image resolution at 10, 20, and 50 mm; and irrigation flow rate; all ureteroscopes were then fully deflected for 200 cycles. Maximum deflection was remeasured. Mean values for each parameter were compared. To examine within-manufacturer consistency, the variance was calculated and an F-test performed to evaluate for equivalence. RESULTS: Both ureteroscopes provided max deflection over 270°. The Pusen flexed to a greater degree than LithoVue. The Pusen lost more deflection with a laser fiber in the working channel. LithoVue had higher resolution at 10 mm, but the ureteroscopes were similar at 20 and 50 mm. Although the working channel diameter is identical, irrigation flow was higher with the Pusen. However, its working channel was 7 cm shorter than LithoVue. After 200 cycles of deflections, LithoVue had less deflection loss, although one ureteroscope was excluded from analysis because of mechanical failure. Variability was minimal and not significant between manufacturers at all measured parameters. CONCLUSIONS: LithoVue and the newer PU3022a have similar "out-of-the-box" performance characteristics and seem durable. These two single-use flexible ureteroscopes performed consistently regardless of the manufacturer.

Let's Get to the Point: Comparing Insertion Characteristics and Scope Damage of Flat-Tip and Ball-Tip Holmium Laser Fibers.

INTRODUCTION: A ball-tip holmium laser fiber (TracTip; Boston Scientific) has been developed to theoretically reduce damaging friction forces generated within a ureteroscope working channel. We compared the insertional forces and damage with a ureteroscope inner lining when inserting standard flat-tip and ball-tip laser fibers. MATERIALS AND METHODS: A standard ureteroscope channel liner was placed in a 3D-printed plastic mold. Molds were created at four angles of deflection (30°, 45°, 90°, and 180°) with a 1 cm radius of curvature. New 200 µm ball-tip (TracTip; Boston Scientific) and 200 µm flat-tip (Flexiva; Boston Scientific) laser fibers were advanced through the liner using a stage controller. A strain gauge was used to measure force required for insertion. Each fiber was passed 600 times at each angle of deflection. The ureteroscope liner was changed every 150 passes. Leak testing was performed every 50 passes or when the insertional force increased significantly to assess damage to the liner. RESULTS: At all deflection angles, the average insertional force was significantly lower with the ball-tip laser fibers compared with flat-tip laser fibers (p < 0.001). All trials with the ball-tip lasers were completed at each angle without any leaks. Two of four trials using flat-tip fibers at 45° deflection caused liner leaks (at 91 and 114 passes). At 90° deflection, all flat-tip trials caused liner leaks on first pass. The 180° trials could not physically be completed with the flat-tip laser fiber. Within the flat- and ball-tip groups, an increasing amount of force was needed to pass the fiber as the degree of deflection increased (p < 0.001). CONCLUSIONS: The ball-tip holmium laser fiber can be safely passed through a deflected ureteroscope without causing liner perforation. The standard flat-tip fiber requires greater insertion force at all angles and can cause the ureteroscope liner to leak if it is deflected 45° or more.

Psychiatric Diagnoses and Other Factors Associated with Emergency Department Return within 30 Days of Ureteroscopy.

PURPOSE: Emergency department visits after ureteroscopy are costly and inconvenient. To better understand those at risk we aimed to identify patient demographic, medical and surgical factors associated with 30-day emergency department presentation following ureteroscopy for urolithiasis with particular attention to those with a history of a psychiatric diagnosis. MATERIALS AND METHODS: We retrospectively reviewed 1,576 cases (1,395 adults) who underwent stone related ureteroscopy during 3 years at a total of 2 hospitals. We collected patient demographics, medical history and operative details. The primary outcome was return to the emergency department within 30 days of ureteroscopy. Logistic regression was performed to examine factors associated with emergency department presentation. RESULTS: Of the patients 613 (43.9%) had a history of psychiatric diagnosis. Of those with ureteroscopy encounters 12.6% returned to the emergency department within 30 days of ureteroscopy, including 58.8% with a history of psychiatric diagnosis. On multivariable analysis variables associated with emergency department return included a history of psychiatric diagnosis (OR 1.57, p = 0.012), uninsured status (OR 2.46, p = 0.001) and a stone only in the kidney (OR 1.76, p = 0.022). Patients who returned to the emergency department had had more emergency department visits in the year prior to surgery (OR 1.40, p <0.001). On univariable analysis older patients and those with longer operative time were more frequently admitted from the emergency department (OR 1.03, p = 0.002 and OR 1.96, p = 0.03. respectively) while uninsured patients were admitted less frequently (OR 0.19, p = 0.013). No difference was noted in admissions between those with a psychiatric diagnosis and all others (60.7% vs 55.8%, p = 0.48). CONCLUSIONS: We identified factors associated with emergency department return after ureteroscopy, including a history of psychiatric diagnosis, uninsured status and emergency department visits in the year before surgery. These patients may benefit from targeted interventions to help avoid unnecessary emergency department visits.

Antibiotic Utilization Before Endourological Surgery for Urolithiasis: Endourological Society Survey Results.

INTRODUCTION: Ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) are common procedures performed to treat kidney stones. Despite advances in technology/technique, serious infectious complications can occur. To better understand the preoperative antibiotic administration patterns and adherence to guidelines from the American Urological Association (AUA) and the European Association of Urology (EAU), members of the Endourological Society were sent a clinical vignette-based survey to assess the antibiotic use in a variety of pre-URS and pre-PCNL scenarios. METHODS: Endourological Society members were e-mailed a survey that queried antibiotic therapy duration before uncomplicated URS and PCNL with negative and asymptomatic positive preoperative urine cultures (PUCs). For negative PUC questions, selecting more perioperative antibiotics was considered a "prolonged" course as it extends past the maximum of 24-hour perioperative prophylaxis recommended by both the AUA and EAU. RESULTS: The response rate was 16.3% for a total of 326 responders. Twenty-one percent to 39% of respondents reported giving prolonged courses of preoperative antibiotics before a URS or PCNL with a negative PUC (p < 0.0001). When presented with a negative PUC, more prolonged antibiotic courses were reported with the following hierarchy: PCNL for 2 cm intrarenal stones (39%) > URS for 12 mm renal pelvis stone (28%) > URS for 7 mm distal ureteral stones (21%) (p < 0.0001). In both negative and positive PUC questions, differences were noted in preoperative antibiotic prescribing patterns among site of practice (United States, Canada, Europe, Asia, South America, and Others), type of practice (academic vs all others), years in practice (<10 or ≥10 years), and surgical volume (URS and PCNL >100 or ≤100 annual cases). CONCLUSIONS: Adherence to guidelines on antibiotic administration before PCNL and URS with a negative PUC varies by scenario and provider. In 21% to 39% of negative PUC cases, reported antibiotic use before a URS or PCNL is not consistent with recommendations from the AUA and EAU. Before a positive PUC URS or PCNL, nearly all surveyed provide preoperative antibiotics; however, the regimen length is variable.

Disproportionate Use of Inpatient Care by Older Adults With Kidney Stones.

OBJECTIVE: To describe variation in utilization and costs of inpatient care for patients with kidney stones, examining associations with older age. MATERIALS AND METHODS: Using the Nationwide Inpatient Sample we examined inpatient discharges with stone diagnoses from 2007 to 2011. We examined length of stay, hospitalization cost, and postdischarge care utilization using multivariable regression to identify associations between patient/hospital characteristics and resource. RESULTS: An estimated 1.7 million hospital discharges for stone disease occurred during the study period. Median length of stay was 2.1 days with a median cost of $6300. Hospital use was substantially higher among persons ≥65 years old (older adults) as compared to those aged 18-64 (younger adults): median length of stay was 3.1 days, with 25% staying more than 5.9 days. Older adults were significantly more likely to utilize home health (odds ratio [OR] 3.6) or skilled nursing (OR 5.0) after discharge. Older adults accounted for 1 in 3 hospital discharges, 40% of costs, and half of postdischarge care utilization. They were more likely to be septic during hospitalization (OR 1.8) which doubled costs per episode, but less likely to receive surgery (OR 0.93). CONCLUSION: While historically at lower risk for kidney stones compared to younger adults, older adults utilizing inpatient care account for a disproportionate share of the economic burden of disease. Utilization is higher for older adults across multiple dimensions, including hospital costs, length of stay, and postdischarge care. These findings suggest that efforts to understand and mitigate the impact of kidney stones on this vulnerable population are required.

Next-Generation Single-Use Ureteroscopes: An In Vitro Comparison.

INTRODUCTION: Single-use ureteroscopes have been gaining popularity in recent years. We compare the optics, deflection, and irrigation flow of two novel single-use flexible ureteroscopes-the YC-FR-A and the NeoFlex-with contemporary reusable and single-use flexible ureteroscopes. METHODS: Five flexible ureteroscopes, YC-FR-A (YouCare Tech, China), NeoFlex (Neoscope, Inc., USA), LithoVue (Boston Scientific, USA), Flex-Xc (Karl Storz, Germany), and Cobra (Richard Wolf, Germany), were assessed in vitro for image resolution, distortion, field of view, depth of field, color representation, and grayscale imaging. Ureteroscope deflection and irrigation were also compared. RESULTS: The YC-FR-A showed a resolution of 5.04 lines/mm and 4.3% image distortion. NeoFlex showed a resolution of 17.9 lines/mm and 14.0% image distortion. No substantial difference was demonstrated regarding the other optic characteristics between the two. Across all tested ureteroscopes, single-use or reusable, the digital scopes performed best with regard to optics. The YC-FR-A had the greatest deflection at baseline, but lacks two-way deflection. The NeoFlex had comparable deflection at baseline to reusable devices. Both ureteroscopes had substantial loss of deflection with instruments in the working channel. The YC-FR-A had the greatest irrigation rate. The NeoFlex has comparable irrigation to contemporary ureteroscopes. CONCLUSIONS: The YouCare single-use fiberoptic flexible ureteroscope and NeoFlex single-use digital flexible ureteroscope perform comparably to current reusable ureteroscopes, possibly making each a viable alternative in the future. Newer YouCare single-use flexible ureteroscopes with a digital platform and two-way deflection may be more competitive, while the NeoFlex devices are undergoing rapid improvement as well. Further testing is necessary to validate the clinical performance and utility of these ureteroscopes, given the wide variety of single-use devices under development.

Comparison of Radiation Exposure from Fixed Table Fluoroscopy to a Portable C-Arm During Ureteroscopy.

INTRODUCTION: Current treatment practices within the field of endourology require the routine use of radiation exposure to provide adequate imaging during urologic procedures. One such procedure requiring repeated radiation exposure during treatment is ureteroscopy. We set out to compare estimated fluoroscopic radiation exposures employing fixed table and portable C-arm fluoroscopy. MATERIALS AND METHODS: A cross-sectional dosimetry phantom model was placed supine on both fixed fluoroscopy and standard operating room tables. The models were then exposed to three separate 5-minute runs of fluoroscopic exposure. Metal oxide semiconductor field effect transistor dosimeters were utilized in organ-specific locations to determine specific radiation exposure dosages. Absorbed radiation was determined for each organ location for both fluoroscopy units. Organ dose volumetric corrections were performed for skin and red bone marrow, to correct for the nonirradiated portion. Organ dose rate (ODR, mGy/s) and effective dose rate (EDR, mSv/s) were calculated, with values reported as mean ± standard deviation. RESULTS: There were found to be statistically significant elevations for both total EDR and organ-specific dose rates with the use of fixed table fluoroscopy compared with C-arm fluoroscopy. EDR was found to be 0.0240 ± 0.0019 mSv/s for the fixed table unit and 0.0029 ± 0.0005 mSv/s for the C-arm unit (p = 0.0024). Internal organs exposed to the most radiation during fixed table fluoroscopy included the gall bladder and stomach in comparison to C-arm fluoroscopy, which found elevated exposure in the kidneys, pancreas, and spleen. CONCLUSION: The routine use of fixed table fluoroscopy results in significantly elevated estimated organ doses and EDR when directly compared with C-arm fluoroscopy in model trials. This difference should be taken into consideration by practicing urologists when patient treatment requires the use of fluoroscopy to maintain radiation exposure as low as reasonably achievable.

Benchtop and Initial Clinical Evaluation of the ShockPulse Stone Eliminator in Percutaneous Nephrolithotomy.

PURPOSE: Standardized bench testing of the new ShockPulse™ intracorporeal lithotripter was performed against three commercially available lithotripsy systems to determine differences and nuances in performance. MATERIALS AND METHODS: The ShockPulse intracorporeal lithotripter was tested against the LUS-2™, CyberWand,™ and EMS LithoClast™ in a standardized bench setting using hard (Ultracal-30) and soft (plaster of Paris) stone phantoms. An in vitro kidney model was used to record the time needed to fragment stone samples into retrievable-sized pieces. The time needed to fully comminute and evacuate stone samples was also recorded. The efficacy of each device at various applied pressures was determined using a hands-free apparatus, which was used to apply 1.0, 1.5, and 2.0 pounds of fixed force. RESULTS: For hard and soft stones, the time needed to create retrievable fragments was similar among all systems (p = 0.585). The ShockPulse was significantly faster than the LUS-2 and LithoClast at fully fragmenting and evacuating stone samples (p = 0.046), while the CyberWand was significantly slower than all three systems at this task (p = 0.001). When fixed forces were applied to a large stone phantom, the ShockPulse and CyberWand were significantly faster than the LUS-2 and LithoClast (p < 0.0001). When groups of smaller stones were tested, the ShockPulse was significantly faster at 1.0 pound (p < 0.001) and 1.5 pounds (p < 0.002) of force. At 2.0 pounds, no differences were observed (p = 0.09). CONCLUSIONS: The ShockPulse is equally as effective and, in some circumstances, more effective than the three commercially available devices against which it was tested in an in vitro setting.