Ureteroscope Deflection Research Articles

Optimal deflection techniques for flexible and navigablesuction ureteral access sheaths (FANS): a comparative in vitro PEARLS analysis.

Flexible and navigable suctionureteral access sheaths (FANS) have been introduced without current evidence on how to optimize deflection. Aim was to evaluate in vitro deflection angles with 2 different FANS techniques-sheath advancement and ureteroscope deflection; and effects of sheath size-ureteroscope combinations. We evaluated in vitro deflection angles of 10/12Fr, 11/13Fr and 12/14Fr FANS (Hunan Reborn Medical Co. Ltd) with six single-use flexible ureteroscopes (Pusen Uscope 7.5Fr, OTU WiScope 7.5Fr, OTU WiScope 8.6Fr, Innovex EU-scope 8.7Fr, Red Pine RP-U-C12 8.7Fr and Boston Scientific Lithovue 9.5Fr). Two deflection techniques were tested: (1) sheath advancement-advancing the sheath forward over a maximally deflected ureteroscope, and (2) ureteroscope deflection-maximally deflecting the ureteroscope from various starting positions relative to tip of the sheath. Intra and inter-scope comparisons of maximum deflection angles were significantly different (all ANOVA p < 0.01). Largest maximumangles for all ureteroscopes were with the sheath advancement technique (range 218°-277°), and second largest for most scopes using the ureteroscope deflection technique at tip (range 111°-212°), mostly deviating from manufacturer specifications (range 270°-275°). 10/12Fr and 11/13Fr sheath sizes were more flexible than 12/14Fr. Largest angles were with 11/13Fr sheath-OTU8.6Fr/Innovex8.7Fr combinations. Optimal deflection with FANS is achieved using either a sheath advancement technique, or ureteroscope deflection technique at tip. Despite using these optimized techniques, deflection angles specified by manufacturers seem hardly achievable. The sheath advancement technique and 11/13Fr sheath-OTU8.6Fr/Innovex8.7Fr combinations may be better suited for lower pole situations. Urologists should be aware of these differences and apply the findings to their FANS technique.

Advances in laser technology and fibre-optic delivery systems in lithotripsy.

The flashlamp-pumped, solid-state holmium:yttrium-aluminium-garnet (YAG) laser has been the laser of choice for use in ureteroscopic lithotripsy for the past 20 years. However, although the holmium laser works well on all stone compositions and is cost-effective, this technology still has several fundamental limitations. Newer laser technologies, including the frequency-doubled, double-pulse YAG (FREDDY), erbium:YAG, femtosecond, and thulium fibre lasers, have all been explored as potential alternatives to the holmium:YAG laser for lithotripsy. Each of these laser technologies is associated with technical advantages and disadvantages, and the search continues for the next generation of laser lithotripsy systems that can provide rapid, safe, and efficient stone ablation. New fibre-optic approaches for safer and more efficient delivery of the laser energy inside the urinary tract include the use of smaller-core fibres and fibres that are tapered, spherical, detachable or hollow steel, or have muzzle brake distal fibre-optic tips. These specialty fibres might provide advantages, including improved flexibility for maximal ureteroscope deflection, reduced cross section for increased saline irrigation rates through the working channel of the ureteroscope, reduced stone retropulsion for improved stone ablation efficiency, and reduced fibre degradation and burnback for longer fibre life.

PD35-09 COMPARISON OF A NOVEL SINGLE-USE FLEXIBLE URETEROSCOPE TO CURRENTLY EXISTING REUSABLE AND SINGLE-USE FLEXIBLE URETEROSCOPES

You have accessJournal of UrologyStone Disease: Surgical Therapy IV1 Apr 2017PD35-09 COMPARISON OF A NOVEL SINGLE-USE FLEXIBLE URETEROSCOPE TO CURRENTLY EXISTING REUSABLE AND SINGLE-USE FLEXIBLE URETEROSCOPES Daniel Wollin, Ruiyang Jiang, Daniela Radvak, Charles Scales, Michael Ferrandino, W Neal Simmons, Glenn Preminger, and Michael Lipkin Daniel WollinDaniel Wollin More articles by this author , Ruiyang JiangRuiyang Jiang More articles by this author , Daniela RadvakDaniela Radvak More articles by this author , Charles ScalesCharles Scales More articles by this author , Michael FerrandinoMichael Ferrandino More articles by this author , W Neal SimmonsW Neal Simmons More articles by this author , Glenn PremingerGlenn Preminger More articles by this author , and Michael LipkinMichael Lipkin More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.1545AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Due to the high cost and limited durability associated with reusable ureteroscopes, single-use ureteroscopes have been gaining popularity in recent years. We aimed to directly compare the YouCare Single-Use fiberoptic flexible ureteroscope (YC-FR-A) to contemporary reusable/single-use flexible ureteroscopes in regards to optics, resolution, deflection, and irrigation flow. METHODS Four flexible ureteroscopes, YC-FR-A (YouCare Tech, China), LithoVue (Boston Scientific, USA), Flex-Xc (Karl Storz, Germany), and Cobra (Richard Wolf, Germany), were assessed in vitro for image resolution, distortion, color representation, and grayscale imaging. Ureteroscope deflection was tested with an empty channel followed by placement of a 200µm laser fiber and a 1.9F wire basket. Irrigation flow was measured using normal saline at a height of 100cm through an empty channel, channel with 200µm laser fiber, and channel with 1.9F basket. RESULTS The optical and functional characteristics of the four ureteroscopes are shown in Table 1. The YC-FR-A showed a resolution of 5.04 lines/mm and 4.3% image distortion. No substantial difference was demonstrated in color reproducibility or in the discernment of gray-scales between ureteroscopes. The YC-FR-A had an impressive one-way deflection of 349 degrees at baseline but lacks two-way deflection capability. In addition, there was a loss of deflection ability with any instrument in the working channel, with a loss of deflection ranging from 17.7 degrees to 30.3 degrees. With an empty channel, the YC-FR-A showed a maximum flow rate of 59 mL/min, which is the highest flow rate among the tested ureteroscopes. However, the flow rate decreased to 28.7 and 16.7 mL/min with laser fiber and basket in the working channel, respectively. CONCLUSIONS The YouCare Single-Use fiber-optic ureteroscope has comparable resolution to the Cobra fiberoptic ureteroscope but cannot match the two digital ureteroscopes tested. Although the one-way deflection and ergonomics of the YC-FR-A are not intuitive, this scope can be a viable alternative to the current reusable/single-use flexible ureteroscopes on the market; additionally, newer digital models in production may be more competitive. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e666 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Daniel Wollin More articles by this author Ruiyang Jiang More articles by this author Daniela Radvak More articles by this author Charles Scales More articles by this author Michael Ferrandino More articles by this author W Neal Simmons More articles by this author Glenn Preminger More articles by this author Michael Lipkin More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

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.

Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy.

The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A “fiber muzzle brake” was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 ?? ? s , and 300 Hz using a 100 - ? m -core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560 - ? m -outer-diameter, 360 - ? m -inner-diameter tube with a 275 - ? m -diameter through hole located 250 ?? ? m from the distal end. The fiber tip was recessed a distance of 500 ?? ? m . Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40 ± 4 ?? mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 ± 4 ?? s

PD18-11 COMPARISON OF AN ELECTRIC PULSE LITHOTRIPTER TO THE HOLMIUM LASER: STONE FRAGMENTATION EFFICIENCY AND IMPACT ON FLEXIBLE URETEROSCOPE DEFLECTION AND FLOW

INTRODUCTION AND OBJECTIVES: A new intracorporeal lithotriptor uses a nanosecond duration electrical discharge through a flexible coaxial probe to endoscopically fragment urinary stones. This device was compared to a holmium laser with regards to stone fragmentation efficiency and their impact on flexible ureteroscope deflection and flow of irrigation. METHODS: Using a custom bench model, stone fragmentation efficiency of the Nano-electric Pulse Lithotriptor (NPL, Lithotech Group, Israel) was evaluated with a begostone (mixture 5:2) confined under 0.9% normal saline atop sequential mesh sieves. Two NPL probe sizes (2.0 and 3.6F) and two holmium laser fibers (200 mm and 365mm) were evaluated using 6mm begostones. Time to first break, time to complete break (all fragments <3mm), and overall fragment sizes were measured. Ureteroscope deflection was tested in 5 new 4th generation flexible ureteroscopes, with an empty channel followed by placement of a 2.0F NPL probe, a 2.4F NPL probe, a 200mm laser fiber, and a 1.9F wire basket. Ureteroscope irrigation flow was measured using normal saline at 100 cm, with an empty channel and then with a 2.0F NEP probe, a 200mm laser fiber, and a 1.9F wire basket. RESULTS: The 2.0F NPL showed improved stone fragmentation efficiency compared to the 200mm laser (86 mg/min vs. 52 mg/min, p 1⁄4 0.014) as did the 3.6F NPL vs. the 365mm laser (173 mg/min vs. 80 mg/min, p1⁄40.05). The NPL created more 1-2 mm fragments, while the laser created more dust (< 1 mm fragments); the difference was more pronounced between the larger NPL and laser probes. In the 5 ureteroscopes tested, ureteroscope deflection was reduced by an average of 3.75 with the 2.0F NPL probe and 22.25 with the 2.4F NLP probe (compared to 5.25 with the laser and 2.75 with the basket). Irrigation flow through the ureteroscope was 36.5 ml/min on average, and was reduced to 18.3 ml/min with the 200mm laser fiber, and to 6.3 ml/min with the 2.0F NEP probe. CONCLUSIONS: The Nano-electric pulse lithotripter produces improved stone fragmentation efficiency as compared to the holmium laser. However the 2.0F and 2.4F NPL probes limit flow and the 2.4F probe limits ureteroscope deflection.

MP33-18 FOURTH GENERATION FLEXIBLE URETEROSCOPES: A COMPARISON OF OPTICS, DEFLECTION AND FLOW

You have accessJournal of UrologyStone Disease: Surgical Therapy III1 Apr 2016MP33-18 FOURTH GENERATION FLEXIBLE URETEROSCOPES: A COMPARISON OF OPTICS, DEFLECTION AND FLOW Adam Kaplan, Daniela Radvak, Richard Shin, Annika Ackerman, Tony Chen, Fernando Cabrera, Joanne Dale, Michael Ferrandino, Charles Scales, Neal Simmons, Glenn Preminger, and Michael Lipkin Adam KaplanAdam Kaplan More articles by this author , Daniela RadvakDaniela Radvak More articles by this author , Richard ShinRichard Shin More articles by this author , Annika AckermanAnnika Ackerman More articles by this author , Tony ChenTony Chen More articles by this author , Fernando CabreraFernando Cabrera More articles by this author , Joanne DaleJoanne Dale More articles by this author , Michael FerrandinoMichael Ferrandino More articles by this author , Charles ScalesCharles Scales More articles by this author , Neal SimmonsNeal Simmons More articles by this author , Glenn PremingerGlenn Preminger More articles by this author , and Michael LipkinMichael Lipkin More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.1375AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Flexible ureteroscopes remain in continual evolution, with improved optical characteristics and maneuverability with each generation. They now have smaller diameters than their predecessors and improved imaging capabilities, among other benefits. In this study, three ureteroscopes were directly compared with regards to optics, ureteroscope deflection and irrigation flow. METHODS Two digital flexible ureteroscopes including the Flex-Xc (Karl Storz, Germany) and URF-V2 (Olympus, Japan) and one fiberoptic flexible ureteroscope (URF-P6, Olympus, Japan) were assessed in vitro for image resolution, distortion, field of view, depth of field, grayscale imaging and color representation. Ureteroscope deflection was tested with an empty channel followed by placement of a 200 μm laser fiber, 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 optical characteristics of the three ureteroscopes are shown in Table 1. The digital platforms showed superior resolution and depth of field while the Fiberoptic platform had a larger field of view. No substantial difference was demonstrated in color reproducibility or grayscale discernment. Maximal deflection of each ureteroscope is shown in table 1. There was no significant difference in impact on deflection between the ureteroscopes by instruments in the working channel. With an empty channel, the flow rates of the URF-V2 and URF-P6 were identical and significantly lower than the Flex-Xc (p=0.001). The Flex-Xc maintained significantly faster flow with instruments in the channel than both the URF-V2 and URF-P6 (p=0.03). CONCLUSIONS The flexible ureteroscopes tested showed excellent optical, deflection and flow capabilities. The resolution of the digital ureteroscopes is superior to the fiberoptic scope, yet the field of view is limited. The Flex-Xc showed deflection comparable to the URF-P6, and improved flow rates over the URF-V2 and URF-P6. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e443-e444 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Adam Kaplan More articles by this author Daniela Radvak More articles by this author Richard Shin More articles by this author Annika Ackerman More articles by this author Tony Chen More articles by this author Fernando Cabrera More articles by this author Joanne Dale More articles by this author Michael Ferrandino More articles by this author Charles Scales More articles by this author Neal Simmons More articles by this author Glenn Preminger More articles by this author Michael Lipkin More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Miniature ball-tip optical fibers for use in thulium fiber laser ablation of kidney stones.

Optical fibers, consisting of 240-μm-core trunk fibers with rounded, 450-μm-diameter ball tips, are currently used during Holmium:YAG laser lithotripsy to reduce mechanical damage to the inner lining of the ureteroscope working channel during fiber insertion and prolong ureteroscope lifetime. Similarly, this study tests a smaller, 100-μm-core fiber with 300-μm-diameter ball tip during thulium fiber laser (TFL) lithotripsy. TFL was operated at a wavelength of 1908 nm, with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times were measured, and ablation rates were calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to track ball tip degradation and determine number of procedures completed before need for replacement. A high speed camera also recorded the cavitation bubble dynamics during TFL lithotripsy. Additionally, saline irrigation rates and ureteroscope deflection were measured with and without the presence of TFL fiber. There was no statistical difference (P>0.05) between stone ablation rates for single-use ball tip fiber (1.3±0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3±0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3±0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged greater than four stone procedures before failure, defined by rapid decline in stone ablation rates. Mechanical damage at the front surface of the ball tip was the limiting factor in fiber lifetime. The small fiber diameter did not significantly impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and into the ureter without risk of instrument damage or tissue perforation, and without compromising stone ablation efficiency during TFL lithotripsy.

Evaluation of Novel Ball-Tip Holmium Laser Fiber: Impact on Ureteroscope Performance and Fragmentation Efficiency

A novel ball tip (BT) holmium laser fiber has recently been developed, which features a modified rounded tip. The modification is purported to aid in insertion and minimize damage to the ureteroscope working channel. We evaluated this laser fiber with regard to stone comminution, tip degradation, insertional force into the ureteroscope, and impact on ureteroscope deflection. A 242 μm BT fiber and a standard flat tip (SF) fiber were compared. Four kilojoules was delivered to a BegoStone over a constant surface area using settings of 0.2/50, 0.6/6, 0.8/8, and 1 J/10 Hz. Fiber tip degradation was measured at 1 and 4 kJ. Ureteroscope deflection was measured with the Olympus URF-P5, URF-P6, and URF-V. Insertion force into a 270° angled ureteroscope sheath model was measured. A sample size of five fibers was used for each comminution energy setting. Comminution increased with pulse energy without significant difference between fibers. No significant differences in tip degradation were observed. Both fibers reduced deflection (10°-30°) in all ureteroscopes without significant differences between fibers. Four new fibers paired with new sheath models were used to test insertion force. The BT insertion forces were approximately one-third of the SF. One SF fiber caused significant damage to the sheath and could not be advanced completely. The BT fiber has comparable comminution, tip degradation, and ureteroscope deflection performance compared with the SF fiber while exhibiting reduced insertion force within an aggressively deflected working sheath. The new tip design is likely protective of the working channel without loss of performance.

Thulium fiber laser ablation of kidney stones using a 50-μm-core silica optical fiber

Our laboratory is currently studying the experimental thulium fiber laser (TFL) as a potential alternative laser lithotripter to the gold standard, clinical Holmium:YAG laser. We have previously demonstrated the efficient coupling of TFL energy into fibers as small as 100-μm-core-diameter without damage to the proximal end. Although smaller fibers have a greater tendency to degrade at the distal tip during lithotripsy, fiber diameters (≤200 μm) have been shown to increase the saline irrigation rates through the working channel of a flexible ureteroscope, to maximize the ureteroscope deflection, and to reduce the stone retropulsion during laser lithotripsy. In this study, a 50-μm-core-diameter, 85-μm-outer-diameter, low-OH silica fiber is characterized for TFL ablation of human calcium oxalate monohydrate urinary stones, ex vivo. The 50-μm-core fiber consumes approximately 30 times less cross-sectional area inside the single working channel of a ureteroscope than the standard 270-μm-core fiber currently used in the clinic. The ureteroscope working channel flow rate, including the 50-μm fiber, decreased by only 10% with no impairment of ureteroscope deflection. The fiber delivered up to 15.4±5.9 W under extreme bending (5-mm-radius) conditions. The stone ablation rate measured 70±22 μg/s for 35-mJ-pulse-energy, 500-μs-pulse-duration, and 50-Hz-pulse-rate. Stone retropulsion and fiber burnback averaged 201±336 and 3000±2600 μm, respectively, after 2 min. With further development, thulium fiber laser lithotripsy using ultra-small, 50-μm-core fibers may introduce new integration and miniaturization possibilities and potentially provide an alternative to conventional Holmium:YAG laser lithotripsy using larger fibers.

Hollow steel tips for reducing distal fiber burn-back during thulium fiber laser lithotripsy

The use of thulium fiber laser (TFL) as a potential alternative laser lithotripter to the clinical holmium:YAG laser is being studied. The TFL's Gaussian spatial beam profile provides efficient coupling of higher laser power into smaller core fibers without proximal fiber tip degradation. Smaller fiber diameters are more desirable, because they free up space in the single working channel of the ureteroscope for increased saline irrigation rates and allow maximum ureteroscope deflection. However, distal fiber tip degradation and "burn-back" increase as fiber diameter decreases due to both excessive temperatures and mechanical stress experienced during stone ablation. To eliminate fiber tip burn-back, the distal tip of a 150-μm core silica fiber was glued inside 1-cm-long steel tubing with fiber tip recessed 100, 250, 500, 1000, or 2000 μm inside the steel tubing to create the hollow-tip fiber. TFL pulse energy of 34 mJ with 500-μs pulse duration and 150-Hz pulse rate was delivered through the hollow-tip fibers in contact with human calcium oxalate monohydrate urinary stones during ex vivo studies. Significant fiber tip burn-back and degradation was observed for bare 150-μm core-diameter fibers. However, hollow steel tip fibers experienced minimal fiber burn-back without compromising stone ablation rates. A simple, robust, compact, and inexpensive hollow fiber tip design was characterized for minimizing distal fiber burn-back during the TFL lithotripsy. Although an increase in stone retropulsion was observed, potential integration of the hollow fiber tip into a stone basket may provide rapid stone vaporization, while minimizing retropulsion.

1551 ENDOSCOPIC FORCEPS FOR URETEROSCOPY: A COMPARATIVE IN VITRO ANALYSIS

You have accessJournal of UrologyStone Disease: New Technology1 Apr 20131551 ENDOSCOPIC FORCEPS FOR URETEROSCOPY: A COMPARATIVE IN VITRO ANALYSIS Carl Sarkissian, Giovanni Marchini, Shubha De, and Manoj Monga Carl SarkissianCarl Sarkissian Cleveland, OH More articles by this author , Giovanni MarchiniGiovanni Marchini Cleveland, OH More articles by this author , Shubha DeShubha De Cleveland, OH More articles by this author , and Manoj MongaManoj Monga Cleveland, OH More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.3061AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The objective of this study was to compare different grasper devices in terms of opening dynamics, grasping effectiveness, safety, and influence on flexible ureteroscope deflection. METHODS The Captura (2.8F, Cook Medical), Platinum (3.0F, Bard Urological), TriClaw (2.4F, UroGyn), Graspit (2.6F, Boston Scientific), and Boston Scientific Tricep (2.4F, 3.0F; 3.0F non-retracting) graspers opening dynamics were evaluated using high-resolution images; grip strength by measuring maximum tensional force applied while grasping stone models attached to an in-line load cell (Fig. 1A,B); safety profile by the maximum force required to perforate aluminum foil (Fig. 2A); impact on deflection by measurement of maximum deflection and bending radius after insertion of the grasper through a flexible ureteroscope. Grip strength and perforation forces were compared with Tukey's test assuming unequal variance. RESULTS The TriClaw and Graspit had greater grip strengths than all other devices (Fig. 1C). Captura (1.92 N) and Tricep 2.4F (1.72 N) required the greatest forces to perforate aluminum foil (Fig. 2B). The Triceps and Captura required the least distance to attain a grasping width of 5 mm (Fig. 3). Ureteroscope deflection was least impacted by the Tricep 2.4F (213∥; 1.35 cm radius), Graspit (207∥; 1.35 cm radius) and TriClaw (206∥; 1.3 cm)(Fig. 4). CONCLUSIONS There are significant differences in opening dynamics, grip strength, perforation forces, and ureteroscope deflection among ureteroscopic graspers that may predict clinical performance capabilities. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e635-e637 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Carl Sarkissian Cleveland, OH More articles by this author Giovanni Marchini Cleveland, OH More articles by this author Shubha De Cleveland, OH More articles by this author Manoj Monga Cleveland, OH More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Endoscopic Forceps for Ureteroscopy: A Comparative In Vitro Analysis

To evaluate the functional characteristics of different ureteroscopic graspers. The Captura (2.8F, Cook Medical, Bloomington, IN), Platinum (3.0F, Bard Urological, Covington, GA), TriClaw (2.4F, UroGyn Medical, Inc., Valapraiso, IN), Graspit (2.6F, Boston Scientific, Natick, MA), and Boston Scientific Tricep (2.4F, 3.0F, and 3.0F non-retracting) graspers were tested. Opening dynamics were evaluated using high-resolution images. Grip strength was determined by measuring the maximum tensional force applied while grasping stone models attached to an inline load cell. Safety profile was evaluated by the maximum force required to perforate aluminum foil. Impact on ureteroscope deflection was assessed by measurement of maximum deflection (baseline = 247°) and bending radius after advancing each grasper through a flexible ureteroscope working channel. The Tukey test for inequality assuming unequal variance with Bonferroni adjustment was used to compare grip strength and perforation forces. The Tricep (2.4F, 3.0F NR, and 3.0F) and Captura graspers required the least distance (7.9-8.1 mm) to attain a grasping width of 5 mm. When compared across all stone models, the TriClaw and Graspit had greater grip strengths than all other devices. The Captura (1.92 ± 0.43 N) and Tricep 2.4F (1.72 ± 0.88 N) required the greatest forces to perforate aluminum foil. Ureteroscope deflection was least impacted by the Tricep 2.4F (213°, 1.35 cm radius), Graspit (207°, 1.35 cm radius), TriClaw (206°, 1.3 cm radius), and all graspers could be deployed and operated at maximum deflection. There are significant differences in opening dynamics, grip strength, perforation forces, and ureteroscope deflection among ureteroscopic graspers that may predict clinical performance capabilities.

Hand Problems Among Endourologists

Endourology has evolved rapidly for the management of both benign and malignant disease of the upper urinary tract. Limited data exist, however, on the occupational hazards posed by complex endourologic procedures. The aim of this study was to determine the prevalence and possible causes of hand problems among endourologists who routinely perform flexible ureteroscopy compared with controls. An online computer survey targeted members of the Endourological Society and psychiatrists in academic and community settings. A total of 600 endourologists and 578 psychiatrists were contacted by e-mail. Invited physicians were queried regarding their practice settings and symptoms of hand pain, neuropathy, and/or discomfort. Survey responses were obtained from 122 (20.3%) endourologists and 74 (12.8%) psychiatrists. Of endourologists, 61% were in an academic setting and 70% devoted their practice to endourology. Endourologists were in practice for a mean 13 years, performing 4.5 ureteroscopic cases per week with a mean operative time of 50 minutes. Hand/wrist problems were reported by 39 (32%) endourologists compared with 14 (19%) psychiatrists (P=0.0486, relative risk [RR]=1.69). Surgeons who preferred counterintuitive ureteroscope deflection were significantly more likely to have problems (56%) compared with intuitive users (27%) (RR 2.07, P=0.0139) or those with no preference (26%) (RR 2.15, P=0.0451). Overall, most respondents (85%) with hand/wrist problems needed either medical or surgical intervention. Hand and wrist problems are very common among endourologists. Future studies are needed to develop more ergonomic platforms and thereby reduce the endourologist's exposure to these occupational hazards.

Influence of Pyelocaliceal Anatomy on the Success of Flexible Ureteroscopic Approach

Some particularities of pyelocaliceal anatomy are described to influence the success rate of flexible ureteroscopy. The aim of this study was to evaluate the correlation between anatomy (infundibulopelvic angle, length of the inferior caliceal infundibulum) and the success of flexible ureteroscopic approach of lower calyx. We studied 47 patients in whom flexible ureteroscopic procedures were performed between October 2002 and October 2006: 43 cases with inferior caliceal calculi or multiple caliceal (including the inferior calyx) lithiasis and 4 patients with inferior calyx diverticulae and intradiverticular lithiasis. In patients with multiple caliceal calculi, we only evaluated the success of flexible ureteroscopic approach of the inferior caliceal ones. Infundibulopelvic angle was wider than 90 degrees in 8 cases, ranged between 30 degrees and 90 degrees in 35 cases, and was smaller than 30 degrees in 4 cases. The success rate was 87.5% (7/8 patients) in patients with infundibulopelvic angle wider than 90 degrees, 74.3 % (26/35 patients) when this angle ranged between 30 degrees and 90 degrees, and 0 % (0/4 patients) in patients with infundibulopelvic angle smaller than 30 degrees. In patients with infundibulopelvic angle between 30 degrees and 90 degrees, the success rate was 88.2% when the length of the inferior caliceal infundibulum was shorter than 3 cm and only 61.1% when it was longer. Pyelocaliceal anatomy influences the performances of flexible ureteroscopy. This parameter, lesion location (stone or tumor) and the influence of accessory instruments on flexible ureteroscope's deflection should be evaluated before recommending flexible ureteroscopic approach.

Alteration in Irrigant Flow and Deflection of Flexible Ureteroscopes with Nitinol Baskets

Introduction of an instrument into the working channel of ureteroscopes adversely affects flow and deflection. We evaluated the alterations in ureteroscope channel flow and deflection caused by available Nitinol(R) baskets. We compared the effects of 11 Nitinol baskets on irrigation flow and deflection of three flexible ureteroscopes (Olympus P3, ACMI DUR8, and ACMI DUR8 Elite). ANOVA was used to compare the loss of flow and deflection for each basket, with P values adjusted for multiple comparisons by the Tukey method. Ureteroscope flow and deflection were progressively adversely affected by all baskets as their diameter increased. The average baseline irrigant flow (46.6 mL/min) was decreased significantly: by 78.5% (to 9.9 mL/min), with the smaller baskets (Microvasive 1.9F and Cook 2.2F) and by 99.1% (to 0.4 mL/min) with the larger baskets (ACMI 3.0F and Microvasive 3.0F). Similarly, the mean baseline upward deflection (162 degrees) decreased by 2 degrees (1.2%) for the Cook 2.4F N-Compass and by 20 degrees (12.3%) for the ACMI 3.0F. Loss of downward deflection from baseline (170 degrees) ranged from 6 degrees (3.5%) for the Microvasive 1.9F to 17 degrees (10%) for the Microvasive 2.6F grasping forceps. The least deterioration in flow and deflection occurred with the two smallest baskets (Microvasive 1.9F and Cook 2.2F). Ureteroscope irrigation flow and deflection deteriorate progressively with larger-caliber Nitinol baskets. The Microvasive 1.9F and Cook 2.2F baskets resulted in the least deterioration of irrigation and deflection metrics. However, basket size is not the only factor responsible for changes in flow and ureteroscope deflection.

Maximizing ureteroscope deflection: “play it straight”

We studied simple maneuvers to optimize active deflection of the flexible ureteroscope. Up to 61° of active deflection is lost if the ureteroscope is not kept in a straight alignment. Holding the ureteroscope taut, placing a super-stiff guidewire in the working channel, or using an access sheath maximizes active deflection.

HOLMIUM: YAG LITHOTRIPSY EFFICIENCY VARIES WITH ENERGY DENSITY

Purpose We test the hypothesis that holmium:YAG lithotripsy efficiency varies with optical fiber sizer and energy settings (energy density). Materials and Methods The 272, 365, 550 and 940 micro m. optical fibers delivered 1 kJ. total holmium:YAG energy to calcium oxalate monohydrate calculi at energy output/pulse of 0.2 to 1.5 J. Stone mass loss was measured for each fiber energy setting. Stone crater width was characterized for single energy pulses. Fiber energy outputs were compared before and after lithotripsy. Results Stone mass loss correlated inversely with optical fiber diameter (p <0.05). Stone loss correlated with energy/pulse for the 365, 550 and 940 micro m. fibers (p <0.001). The 272 and 365 micro m. fibers yielded equivalent stone loss at 0.2 and 0.5 J. per pulse. At energies of 1.0 J. per pulse or greater the 272 micro m. optical fiber was prone to damage, and yielded reduced energy output and stone loss compared to the 365 micro m. fiber (p <0.01). Stone crater width for single pulse energies correlated with energy settings for all fibers (p <0.001). Conclusions Lithotripsy efficiency with the holmium:YAG laser depends on pulse energy output and diameter of the optical delivery fiber, implying that lithotripsy efficiency correlates with energy density. The 365 micro m. fiber is indicated for most lithotripsy applications. The 272 micro m. fiber is susceptible to damage and inefficient energy transmission at energies of 1.0 J. per pulse or greater. The 272 micro m. fiber is indicated at energies of less than 1.0 J. per pulse for small caliber ureteroscopes or when maximal flexible ureteroscope deflection is required.