The "Body Mass Index" of Flexible Ureteroscopes

Miniaturization of flexible ureteroscopes: a comparative trend analysis of 59 flexible ureteroscopes

The purpose of this review is to analyze the trend in miniaturization of flexible ureteroscopes over the past decades, identify the advantages and disadvantages, and determine the correlation of individual parameters with release period. Flexible ureteroscopes mentioned in the literature or those commercially available were searched. To minimize the search bias, the instruments were grouped by release date time periods of < 2000 year, 2000-2009, 2010-2019, and 2020 onwards. The final review included only those instrument models for which data on tip size, overall shaft, working length and channel size had been determined. The correlation among features investigated as well as with release period was also determined. 59 models of flexible ureteroscopes (26 fiber optic and 33 digital scopes) were included. Among the different features investigated among fiber optic endoscopes, only the sizes of the distal tip and overall shaft positively correlated with each other. In contrast to their fiber optic counterparts, a strong positive correlation was observed between tip and channel sizes, whereas negative correlation was found between channel size and overall shaft size and working length of digital scopes. Only distal tip of fiber optic flexible ureteroscopes and overall shaft of digital endoscopes were significantly reduced over their evolution. With the development of technology, there has been an improvement of flexible ureteroscopes and one of the indicators of this trend is a decrease in their size. With a definite trend towards miniaturization over the past decades, a significant correlation was observed in tip size and overall shaft for fiber optic and digital endoscopes, respectively.

Single-Use Flexible Ureteroscopes: How Difficult Is It Today to Stay Up to Date? A Pictorial Review of Instruments Available in Europe in 2023

The invention of the flexible ureteroscope (fURS) and its subsequent spread have revolutionized the surgical management of urolithiasis and upper tract urothelial carcinoma (UTUC). During the last few years, single-use flexible ureteroscopes (su-fURSs) have been developed to improve the limitations of reusable fURSs, namely their cost, durability and risk of device contamination. Since the introduction of the first fully disposable digital fURS, several su-fURSs have been developed by various manufacturers. In this pictorial review, we combined the different physical and technical features of su-fURSs currently available on the market with Food and Drug Administration (FDA) and European Conformity (CE) approval, in order to help surgeons choose the appropriate device according to each case requirement and personal preferences. To the best of our knowledge, 17 su-fURSs with CE and FDA approval have been developed to date.

Single use flexible ureteroscopes: Current status and future directions

Introduction

Single use ureteroscopes are a technological innovation that have become available in the past decade and gained increased popularity. To this end, there are now an increasing number of both benchside and clinical studies reporting outcomes associated with their use. Our aim was to deliver a narrative review in order to provide an overview of this new technology.

Methods

A narrative review was performed to gain overview of the history of the technology's development, equipment specifications and to highlight potential advantages and disadvantages.

Results

Findings from preclinical studies highlight potenial advantages in terms of the design of single use ureteroscopes such as the lower weight and more recent modifications such as pressure control. However, concerns regarding plastic waste and environmental impact still remain unanswered. Clinical studies reveal them to have a non inferior status for outcomes such as stone free rate. However, the volume of evidence, especially in terms of randomised trials remains limited. From a cost perspective, study conclusions are still conflicting and centres are recommended to perform their own micro cost analyses.

Conclusions

Most clinical outcomes for single use ureteroscopes currently match those achieved by reusable ureteroscopes but the data pool is still limited. Areas of continued debate include their environmental impact and cost efficiency.

Single-use flexible ureteroscopes: Comparative in vitro analysis of four scopes

Objective

Single-use flexible ureteroscopes (fURSs) have recently been introduced by different companies. Goal of this in-vitro study was to compare four fURSs.

Methods

We performed in vitro analysis of Uscope 7.5 Fr and Uscope 9.5 Fr (Pusen Ltd., Zhuhai, China), LithoVue 9.5 Fr (LithoVue™, Boston Scientific, MA, USA), and Indoscope 9.5 Fr (Bioradmedisys™, Pune, India). Optical characteristics (image resolution, color representation, and luminosity) were compared at various distances of 10 mm, 20 mm, and 50 mm. Deflection and irrigation were evaluated with and without accessories.

Results

Color perception was comparable for all scopes at 10 mm (p<0.05), while Lithovue 9.5 Fr was comparable with Indoscope 9.5 Fr at the distances of 20 mm and 50 mm. Both scopes were statistically better than both Uscopes at the distances of 20 mm and 50 mm. Image resolution powers were comparable amongst all fURSs at the distances of 10 mm and 20 mm (3.56 line pairs per millimeter [lp/mm]). However, Indoscope (3.56 lp/mm) was superior to LithoVue and Uscope scopes (3.17 lp/mm) at the distance of 50 mm. Luminosity at the distance of 10 mm was comparable for LithoVue and Uscope 9.5 Fr. However, at the distances of 20 mm and 50 mm, LithoVue had the highest luminosity while Uscope 7.5 Fr had the lowest one. Indoscope had lower luminosity than other 9.5 Fr scopes at all distances. With empty working channel and 200 μm laser fiber, Indoscope had the maximum deflection (285°). With basket, Uscope 7.5 Fr had the maximum loss of deflection (30°) while Indoscope had no deflection loss. With empty working channel, all scopes had comparable irrigation flow rates in both deflected and undeflected state. Similarly, with 200 μm laser or basket, irrigation flow rates were comparable in all scopes.

Conclusion

Color representation was equivalent for Indoscope and LithoVue, while being better than Uscope 7.5 Fr and Uscope 9.5 Fr. Image resolution was comparable in all scopes at the distances of 10 mm and 20 mm. Beyond the distance of 10 mm, luminosity of LithoVue was the highest and that of Uscope 7.5 Fr was the lowest. Deflection loss was the minimum with Indoscope and the maximum with 7.5 Fr Uscope. Under all scenarios, irrigation flow rates were comparable in all scopes.

Continuum Robots for Medical Interventions

Continuum robots are not constructed with discrete joints but, instead, change shape and position their tip by flexing along their entire length. Their narrow curvilinear shape makes them well suited to passing through body lumens, natural orifices, or small surgical incisions to perform minimally invasive procedures. Modeling and controlling these robots are, however, substantially more complex than traditional robots comprised of rigid links connected by discrete joints. Furthermore, there are many approaches to achieving robot flexure. Each presents its own design and modeling challenges, and to date, each has been pursued largely independently of the others. This article attempts to provide a unified summary of the state of the art of continuum robot architectures with respect to design for specific clinical applications. It also describes a unifying framework for modeling and controlling these systems while additionally explaining the elements unique to each architecture. The major research accomplishments are described for each topic and directions for the future progress needed to achieve widespread clinical use are identified.

Comparison of pre- and post-surgical images of reusable and single use flexible ureteroscopes: a qualitative analysis

Introduction

Given the fragility of reusable ureterorenoscopes, many single use instruments have appeared on the market. Unfortunately, reuse of these scopes occurs in undeveloped countries in order to cut costs. This raises safety concerns for the patient.

The aim of this article was to macroscopically evaluate the changes that single use flexible ureterorenoscopes (su-fURS) suffer after a retrograde intrarenal surgery (RIRS), and to compare them to reusable fURS.

Material and methods

Pre and post-operative images of the instruments used in 23 RIRS were obtained. All the cases had renal calculi of the inferior calix between 10–15 mm, and all of them were treated with Holmium laser. The ureterorenoscopes used were: Storz^® Flex X2, Storz^® Flex XC, Pusen^® 3022, OTU^® Wiscope, AnQIng^® Innovex and Boston Scientific^® LithoVue. Qualitative comparisons of these were made.

Results

After su-fURS usage, significant damage was observed, especially on the distal tip. Deflection was not compromised. Reusable fURS did not sustain any damage after their use.

Conclusions

fURS are delicate equipment, especially if they are of single use. The considerable damage sustained by single use scopes could mean that reuse of these instruments is dangerous and should be avoided.

Single-use ureteroscopes in ectopic pelvic kidney stones

We analyzed the results of single-use flexible ureteroscopy (su-fURS) with the holmium laser in treating renal stones associated with ectopic pelvic kidney (EPK). The study retrospectively analyzed data of 11 patients diagnosed with EPK and stone disease who underwent su-fURS between May 2017 and November 2019. The analyzed surgical data included the mean operation time, stone-free and complication rates, as well as hospitalization period. Disposable digital flexible ureteroscopes were exclusively used. The mean age was 55, with a 1.2:1 male to female ratio. The mean stone burden was 30±9 mm (ranging from 17 to 49 mm). The mean calculi digitized surface area (DSA) was 299±56 mm² (ranging from 170 to 597 mm²). A ureteral access sheath was used in all 11 patients, and holmium laser lithotripsy was performed (dusting mode parameters: low energy – 0.5J, high frequency – 50 Hz, long pulse; pop-corn mode: high energy >1 J, medium frequency– 10–50 Hz, long pulse; fragmenting mode: high energy >1 J, low frequency <10 Hz, short pulse). The average operative time was 78±19 minutes (ranging from 68 to 144 minutes). The stone-free status (residual fragments <3 mm) after one session was 60.1%, 84.1% after the second session, and 94.4% after the third session. The hospitalization period was 29 hours (ranging from 17 to 39 hours). The overall complications rate (according to the Clavien-Dindo system) was 19.7%. Therefore, su-fURS represents an effective therapeutic approach characterized by a remarkably high stone-free rate and few complications in EPK-associated calculi.

Comparison of a single-use, digital flexible ureteroscope with a reusable, fiberoptic ureteroscope for management of patients with urolithiasis

OBJECTIVES

Ureteroscopy is one of the commonest procedures performed to manage urolithiasis. Flexible ureteroscopy has been traditionally based on reusable, fiber-optic ureteroscopes. Technology advancements permitted the development of single-use scopes with digital image. The aim of this study is to compare efficacy and safety between a reusable, fiberoptic ureteroscope with a single-use, digital scope.

PATIENTS AND METHODS

We collected data based on chart review from a prospectively collected database on a tertiary, high-volume hospital in Greece. Baseline, perioperative and postoperative data were gathered and analyzed. Chi-square and Fisher's exact test was used to compare qualitative data and unpaired t-test for continuous data, with a statistical significance set at a = 0.05.

RESULTS

40 patients underwent flexible ureteroscopy with a single- use digital scope, while 37 with the reusable scope. The two groups were matched regarding baseline characteristics and stone-related parameters. After data analysis, a shorter operative time in favor of single-use flexible ureteroscope was detected (45 vs 65 min, p = 0.001), while safety was also in favor of this type of scope with a significantly higher immediate stonefree rate (70% vs 43%, p = 0.005). Overall complications did not differ between the two groups, although a lower sepsis rate was detected in patients treated with single-use scope.

CONCLUSIONS

Our findings indicate that single-use, digital ureteroscopes are a viable alternative for flexible ureteroscopy and management of urolithiasis, especially in centers with deficient facilities for sterilization and ensured funds for more expensive reusable scopes.

Single-use flexible ureteroscopes: update and perspective in developing countries. A narrative review

Flexible ureteroscopy is a well-established method for treatment of urinary stones but flexible ureteroscopes are expensive and fragile devices with a very limited lifetime. Since 2006 with the advent of digital flexible ureteroscopes a great evolution has occurred. The first single-use flexible ureteroscope was launched in 2011 and new models are coming to the market. The aim of this article is to review the characteristics of these devices, compare their results with the reusable devices and evaluate the cost-benefits of adopting single-use flexible ureteroscopes in developing countries.

How to evaluate a flexible ureterorenoscope? Systematic mapping of existing evaluation methods

Objectives

The objective of this study was to identify, map and review scope‐related and user‐related parameters used to evaluate the quality of flexible ureterorenoscopes. Thereby identifying key items and variability in grading systems.

Methods

A literature search of four databases (MEDLINE [Ovid], EMBASE [Ovid], Web of Science, Google scholar and the Cochrane Library) was performed according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines encompassing articles published up to August 2020. A total of 2386 articles were screened.

Results

A total of 48 articles were included in this systematic scoping review. All studies had a prospective design. Five key items in the assessment of flexible ureterorenoscopy were distinguished: ‘Manoeuvrability’ (87.5%), ‘Optics’ (64.6%), ‘Irrigation’ (56.3%), ‘Handling’ (39.6%) and ‘Durability’ (35.4%). After regrouping, every key item could be divided into specific subcategories. However, the quality assessment showed a wide variation in denomination, method of measurement, circumstances of measurement, tools used during measurements, number of measurements performed, number of observers, and units of outcomes.

Conclusion

The research field regarding quality assessment of ureterorenoscopes is heterogeneous. In this systematic scoping review we identified five key parameters: Manoeuvrability, Optics, Irrigation, Handling and Durability, used to grade flexible ureterorenoscopes. However, within these categories we found a wide variety in terms of method of measurements. A standardised, uniform grading tool is required to assess and compare the quality of flexible ureterorenoscopes in the future.

Ergonomics and Surgeon Comfort During Flexible Ureteroscopy

The technological advancements of flexible ureteroscopy (FURS) and its accessories have resulted in broadening its indications to include the management of complex renal stones, with long operative time. The surgeon's understanding about the ergonomics of the ureteroscopes and their cognizance of the operation theatre layout helps to improve their performance, including the surgical outcomes. This paper will describe the ergonomics that are involved in conducting FURS which in turn will aid in developing a more conducive surgical environment for the surgeon during the procedure, based on scientific literature review and expert opinions in high-volume centres. Proper surgeon position, well-arranged operation theatre layout, monitor and pedal position, anaesthesia type, and surgical team are important factors to decrease musculoskeletal strains for surgeons and increase work efficiency. Different types of flexible ureteroscope have different characters and knowing these special characters leads to better ergonomics during surgery. Robotic-assisted FURS have shown good safety and ergonomics in clinical application.

Initial experience with slimmest single-use flexible ureteroscope Uscope PU3033A (PUSEN™) in retrograde intrarenal surgery and its comparison with Uscope PU3022a: a single-center prospective study

PURPOSE

Single-use disposable digital flexible ureterorenoscope has become an attractive option to reusable scope with many advantages. Currently available single-use digital fURS have outer shaft diameter above 9 Fr which requires large access sheath insertion and sometimes double J stent placement. Recently, 7.5 Fr single-use digital fURS is introduced in market by Pusen. Objective of this study is to compare two Pusen single-use scopes in the clinical setting: 7.5 Fr Uscope PU3033A and 9.5 Fr Uscope PU3022A.

METHODS

30 patients, having renal stones < 2 cm, planned for RIRS were prospectively randomized to two groups: group 1 had 15 patients in which 7.5 Fr Uscope PU3033A and group 2 had 15 patients in which 9.5 Fr Uscope PU3022A was used. The various pre-operative, intra-operative, and post-operative parameters at 1 month along with complications were evaluated for both the scopes by a single surgical team.

RESULTS

Pre-operative parameters including stone characteristics were comparable in both the groups. Three patients in group 2 needed ureteric dilatation prior to 11/13 access sheath insertion, while 10/12 Fr access sheath was placed in all patients in group 1 without manipulation (p = 0.06). Intra-operative vision was comparable in both scopes with an empty working channel and with laser. Hazy vision while lasing in two and one patient in group 1 and group 2, respectively (p = 0.54). In group 1, one had fever and UTI, while in group 2, one had fever post-operatively.

CONCLUSION

7.5 Fr Uscope PU3033A could be introduced with smaller access sheath. The vision, deflection, maneuverability is comparable to 9.5 Fr Uscope PU3022a.

Single-use flexible ureteroscopes: how to choose and what is around the corner?

PURPOSE OF REVIEW

The pace of technology development with single-use endoscopy has led to a range of disposable ureteroscopes. We review the development of single-use scopes, deconstruct the basic design and functional characteristics of available devices, and discuss future directions for next-generation platforms.

RECENT FINDINGS

Currently available devices are differentiated on the basis of several core features. The optical, deflection and irrigation characteristics are marginally different with no device clearly superior in every category. Studies comparing single-use ureteroscopes in patients linked to outcomes are limited. The incorporation of next-generation technologies into these platforms include sensors to monitor intrarenal pressure and temperature, suction of fluid and fragments, and computer vision for artificial intelligence.

SUMMARY

Each ureteroscope has specific features that may be advantageous in different circumstances. Single-use devices could transform the ureteroscope from a visual conduit to a transformative surgical instrument that improves outcomes and reduces complications.

Ergonomics in Endourology: Measurement of Force for Deflection in Contemporary Ureteroscopes

Introduction: Few studies have examined the ergonomic hazards to endourologists during endoscopic procedures. We have evaluated the forces required to deflect different flexible ureteroscopes across a range of measurements with several different standard instruments within the working channel. Methods: Five ureteroscopes were studied: the Uscope, Neoflex, LithoVue^™, URF-P6, and the Flex-X2^™. A pull-force meter (Nextech DFS 500) was attached to the thumb lever to deflect the tip from 30° to 210° at 30° intervals. Measurements were made with upward and downward deflection separately. The forces were reported in Newtons (N) to the nearest 10th, as positive values regardless of the direction of the force. Measurements were made with the channel empty or containing an instrument: a 365 μm laser fiber, a 2.4F Nitinol basket, 3F biopsy forceps, or a 0.038" guidewire using the flexible or the stiff tip. Results: The maximum downward deflection force, measured at 210° of deflection, with an empty channel range from a minimum of 5.7 N in one scope to a maximum of 33.4 N in another. The force necessary for deflection ranges from 2.0 to 7.0 N (0.45-1.57 foot-pounds) at 30° to 8.5 to 25.3 N (1.8-5.69) at 180°. Maximum upward deflection shows similar results with a minimum of 7.9 N in one scope and a maximum of 43.1 N of force in another. Working instruments in the channel increased the force needed for deflection. Conclusions: Forces required for steep deflection of the tip of a flexible ureteroscope reach extremely high levels or limit the deflection capability of the scope. The force is higher with increased deflection and with instruments within the channel.

Device profile of the LithoVue single-use digital flexible ureteroscope in the removal of kidney stones: overview of safety and efficacy

Introduction: Flexible ureteroscopy is a commonly performed urologic procedure for visualization and treatment of the upper urinary tracts. Traditionally, ureteroscopy has been performed with reusable scopes, which have large initial purchasing costs. LithoVue was the first widely adopted single-use flexible ureteroscope clinically available in 2016 and has caused reevaluation of this paradigm. Areas covered: This review is an objective assessment of the LithoVue single-use ureteroscope based on available studies at the time of publication. The authors searched major databases for papers that included the term 'LithoVue' and included relevant papers. The state of the market, technical specifications, results from clinical studies and cost analyses, and competitors are discussed. Expert opinion: The LithoVue single-use flexible ureteroscope has comparable clinical performance to existing reusable ureteroscopes based on available data. Direct clinical comparisons to competing single-use ureteroscopes, many of which are relatively new, are limited. In numerous pre-clinical studies LithoVue performed favorably compared to available competitors. Cost analyses suggest that benefit of single-use ureteroscopes is institution-specific, and will likely be favorable at a low volume of cases and with high local costs for repairs of reusable scopes.

Flexible ureteroscopy: reuse? Or is single use the new direction?

PURPOSE OF REVIEW

Single-use flexible ureteroscopes (su-fURS) aim at overcoming the main limitations of conventional reusable ureteroscopes in terms of acquisition and maintenance costs, breakages, and reprocessing. However, little data exist to date regarding the superiority of su-fURS at this regard. We aimed to perform a systematic literature review on available su-fURS performance with a focus on clinical data for all articles in the last 10 years.

RECENT FINDINGS

To date, more than 10 different su-fURS are available on the market, with different characteristics and performance. Some of these devices have top-level features, almost catching up with those observed in reusable flexible ureteroscopes. Clinical evidence is mainly available only for two models, LithoVue and Uscope PU3022, and to date it is not strong enough to support routine adoption and use of su-fURS, with a consequent lack of consensus of specific clinical indications. Cost-effectiveness analyses seem to indicate an economic disadvantage in the routine adoption of su-fURS. Environmental issues related to the use of su-fURS also remain to be inquired and addressed.

SUMMARY

Since their introduction, su-fURS have gained widespread popularity. Despite their ability at addressing reusable ureteroscope limitations, high-cost and a substantial lack of evidence are still limiting their routine adoption.

Performance Optimization Strategies for Complex Endourologic Procedures

OBJECTIVE

To identify and address factors that may impact a surgeon's performance during endourologic procedures.

METHODS

A literature review was performed for articles focusing on surgical ergonomics, education, sports and performance psychology.

RESULTS

As urologists and trainees have become more comfortable approaching complex pathology endoscopically, there remains an opportunity to refine surgeon-related factors and optimize extrinsic factors to maximize efficiency and provide patients with the highest quality outcomes and safety.

CONCLUSION

Medical centers and training programs should strive to include formal lessons on stress-coping mechanisms, communication, and dedicated ergonomic training, as these all play a role in physician well-being and may lead to improved clinical outcomes.

Characteristics of current digital single-use flexible ureteroscopes versus their reusable counterparts: an in-vitro comparative analysis

Background

Single-use flexible ureterorenoscopes (fURSs) have been recently introduced aiming to offer solutions to the sterilization, fragility and cost issues of the reusable fURSs. In order to be a viable alternative, the single-use scopes must prove similar capabilities when compared to their reusable counterparts. The goal of our in-vitro study was to compare the current reusable and single-use digital fURSs regarding their deflection, irrigation and vision characteristics.

Methods

We compared in-vitro 4 single-use fURSs-LithoVue™ (Boston Scientific, Marlborough, Massachusetts, USA), Uscope™ (Zhuhai Pusen Medical Technology Co. Ltd., Zhuhai, Guangdong Province, China), NeoFlex™ (NeoScope Inc, San Jose, California, USA) and ShaoGang™ (YouCare Technology Co. Ltd., Wuhan, China) versus 4 reusable fURSs-FLEX-X^c (Karl Storz SE & Co KG, Tuttlingen, Germany), URF-V2 (Olympus, Shinjuku, Tokyo, Japan), COBRA vision and BOA vision (Richard Wolf GmbH, Knittlingen, Germany). Deflection and irrigation abilities were evaluated with different instruments inserted through the working channel: laser fibres (200/273/365 µm), retrieval baskets (1.5/1.9/2.2 Fr), guide wires [polytetrafluoroethylene (PTFE) 0.038 inch, nitinol 0.035 inch] and a biopsy forceps. A scoring system was designed to compare the deflection impairment. Saline at different heights (40/80 cm) was used for irrigation. The flow was measured with the tip of the fURS initially straight and then fully deflected. The vision characteristics were evaluated (field of view, depth of field, image resolution, distortion and colour representation) using specific target models.

Results

Overall, the single-use fURSs had superior in-vitro deflection abilities than the reusable fURSs, in most settings. The highest score was achieved by NeoFlex™ and the lowest by ShaoGang™. PTFE guide wire had most impact on deflection for all fURSs. The 200 µm laser fibre had the lowest impact on deflection for the single-use fURSs. The 1.5 Fr basket caused the least deflection impairment on reusable fURSs. At the end of the tests, deflection loss was noted in most of the single-use fURSs, while none of the reusable fURSs presented deflection impairment. ShaoGang™ had the highest irrigation flow. Increasing the size of the instruments occupying the working channel led to decrease of irrigation flow in all fURSs. The impact of maximal deflection on irrigation flow was very low for all fURSs. When instruments were occupying the working channel, the single-use fURSs had slightly better in-vitro irrigation flow than the reusable fURSs. The field of view was comparable for all fURSs, with LithoVue™ showing a slight advantage. Depth of field and colour reproducibility were almost similar for all fURSs. ShaoGang™ and Uscope™ had the lowest resolution. FLEX X^c had the highest image distortion while LithoVue™ had the lowest. Partial field of view impairment was not for Uscope™ and ShaoGang™.

Conclusions

In-vitro, there are differences in technical characteristics of fURSs. It appears that single-use fURSs deflect better than their reusable counterparts. Irrespective of deflection, the irrigation flow of the single-use fURSs was slightly superior to the flow of the reusable fURSs. Overall, reusable fURSs had better vision characteristics than single-use fURSs. Further in-vivo studies might be necessary to confirm these findings.

Reusable flexible ureterorenoscopes are more cost-effective than single-use scopes: results of a systematic review from PETRA Uro-group

Clinical data suggest an equipoise between single-use (disposable) and reusable flexible ureterorenoscope (fURS) in terms of scope characteristics, manipulation, view and clinical outcomes. The procedural cost of reusable fURS is dependent on the initial and repair cost, maintenance and scope sterilization and on the number of procedures performed/repair. We conducted a systematic review on the procedural cost ($) of fURS based on the individual authors reported data on the number of procedures performed before repair and to see if it is a feasible option compared to single use fURS. A systematic review carried out in a Cochrane style and in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist using Medline, Scopus, CINAHL, EMBASE and Cochrane library for all English language articles. All papers on fURS cost analysis were searched from 2000-2018 (19 years), which mentioned the cost of fURS based on the number of procedures performed and the repairs needed (procedure/repair) as reported by the individual authors. Six studies reported on both the number of procedures performed with number of repairs needed and the cost calculated/procedure in the given time period. The number of uses/repair in various studies varied between 8-29 procedures and the cost per procedure varied between $120-1,212/procedure. A significant trend was observed between the decreasing cost of repair with the number of usages. With studies reporting on a minimum of 20 cases/repair the mean cost was around $200/procedure. This is contrast to the disposable scopes such as Lithovue ($1,500-2,000/usage) and Pusen ($700/usage). The cost of reusable fURS is low in centres performing a high volume of procedures. Similarly, when a reasonable volume of procedures is performed before scope repair, the cost is lower than the disposable scopes. Although, the disposable and reusable scopes seem to be comparable in terms of their performance, this review proves that reusable fURS are still more cost effective than disposable scopes.

Single-Use Ureteroscopes

A PubMed search using the terms "single use" and "ureteroscope" was performed to identify published studies on this topic. In addition, the abstracts of the annual meeting of the World Congress of Endourology and the American Urologic Association since 2010 were reviewed. Here we present a review of published studies on single-use ureteroscopes.

Which flexible ureteroscope is the best for upper tract urothelial carcinoma treatment?

PURPOSE

To present attributes of currently available flexible ureteroscopes to define the best flexible ureteroscope for upper tract urothelial carcinoma (UTUC) treatment.

MATERIALS AND METHODS

Scopus and Medline databases were searched for articles relating to performance of flexible ureteroscopes. A consensus for final inclusion of articles judged to be relevant for UTUC treatment was reached between the authors. Instrument characteristics were extracted from manufacturers' product brochures.

RESULTS

Smaller cross-sectional size of instruments is associated with increased probability for successful primary access to the upper urinary tract. The smallest flexible ureteroscopes are fiberoptic scopes. Smaller ureteroscopes also allow comparatively increased irrigation flow at constant intrarenal pressure. Digital flexible ureteroscopes achieve superior image quality compared to their fiberoptic counterparts, at the price of lower end-deflection ability. Image enhancement technologies such as narrow-band imaging (NBI), photodynamic diagnosis (PDD) and Image 1-S (formerly SPIES) are based on subjective image interpretation by the operator. NBI and PDD significantly increase tumor detection rate. The highest subjective image quality score of the Image 1-S technology is reached by the "Clara + Chroma" mode. Single-use ureteroscopes offer potential advantages over reusable scopes, including sterility, absence of contamination, immediate availability and exemption of previous instrument wear.

CONCLUSIONS

Miniaturization, digital image caption and image enhancement technologies seem to be the major determinants defining the best flexible ureteroscope for UTUC treatment. The impact of further factors, such as distal tip design, torque, working channel position, risk of contamination, as well as upcoming technological innovations should be evaluated in randomized controlled trials.

Evaluation of Performance Parameters of the Disposable Flexible Ureterorenoscope (LITHOVUE) in Patients with Renal Stones: A Prospective, Observational, Single-arm, Multicenter Study

We investigated performance parameters of disposable flexible ureterorenoscopy (LITHOVUE) in patients with renal stones in a prospective, multicenter, observational study. Sixty two patients who underwent ureterorenoscopic surgery by LITHOVUE were included. Surgeons using a numerical scale, evaluated the maneuverability of the scopes and general perceptions of visibility related to the monitor and irrigation systems. General pain and fatigue scores were evaluated and compared to existing scopes. Mean patient age was 57.3 years and stone size was 15.4 mm. Clinical success of overall stone removal was 82.3%. Complications occurred in 4 cases of the Clavien classification grade I in a single case and II in 3 cases. Comparative parameters of maneuverability, perception of the monitor system and perception of the irrigation channel were 2.5, 2.5, and 3.0, respectively. The most favorable evaluation of physical strain was about ‘shoulder fatigue’ and ‘hand fatigue’. Unfavorable evaluations were recorded for ‘wrist stiffness’ and ‘thumb fatigue’. Maximal deflection angles of 270° were preserved in 53 cases (85.5%). No pre-stenting procedure and the longer operative time were significant predictors of poorly-preserved deflection angles <270°. LITHOVUE showed good maneuverability and perception scores for the monitor and irrigation systems. LITHOVUE received favorable evaluations on pain and fatigue scores.