Techniques to maximize flexible ureteroscope longevity

Single-use flexible ureteroscopes: practice patterns, attitudes, and preferences for next-generation concepts

Background

Single use flexible ureteroscopes (su-fURS) have emerged as an alternative to reusable flexible ureteroscopes (r-fURS) for the management of upper urinary tract calculi. However, little is known about urologist usage and attitudes about this technology. Through a worldwide survey of endourologists, we assessed practice patterns and preferences for su-fURS.

Methods

An online questionnaire was sent to Endourology Society members in January 2021. The survey explored current su-fURS practice patterns, reasons for/against adoption, and preferences for next generation models including developments in imaging, intra-renal pressure, heat generation, and suction. Responses were collected through QualtricsXM over a 1-month period from surgeons in North America, Latin America, Europe, Asia, Africa, and Oceania. The study was conducted according to the Checklist for Reporting Results of Internet E-Surveys (CHERRIES).

Results

208 (13.9%) members responded to the survey. Most respondents (53.8%) performed >100 ureteroscopies per year. 77.9% of all respondents used su-fURS for less than half of all procedures while only 2.4% used su-fURS for every procedure. 26.0% had never used a su-fURS. Overall, usage was not influenced by a surgeon's geographic region, practice environment, or years of experience. Top reasons for not adopting su-fURS were cost (59.1%) and environmental impact (12.5%). The most desired improvements in design were smaller outer shaft size (19.4%), improved optics and vision (15.9%), and wireless connectivity (13.6%). For next generation concepts, the functions most commonly described as essential or important by respondents was the ability to suction fragments (94.3%) while the function most commonly noted as not important or unnecessary was incorporation of a temperature sensor (40.4%).

Conclusions

su-fURS are not commonly used, even among urologists who perform a high number of fURS. The primary concern for adoption is cost and environmental impact. Suction capability was considered the most important future development.

The cost-effectiveness of reusable flexible ureteroscopes: An institutional audit

Introduction

A flexible ureteroscope (FU) is an important tool in the urologist's armamentarium. This study aims to check the durability and cost-effectiveness of conventional FU.

Methods

The institution registry of damaged FU over the last 7 years was reviewed. A total of 17 flexible scopes were used. The data of 13 scopes (11 Storz fiberoptic and 2 Seesheen digital) are included in this study. A total of 1905 cases were performed. The cost of scope, duration of use, number of cases done by each scope, and nature of damage were evaluated. We compared the cost-effectiveness of conventional scopes with published costs on disposable scopes.

Results

The mean number of cases done by fiberoptic scope was 159 (range 25-334). The total cases done by 2 digital scopes were 135 and 25. The mean life of fiberoptic and digital scopes was 17 (range 4-31) and 8 months, respectively. The mean cost of fiberoptic scope was Indian Rupee (INR) 338,951 ($4082.7221) and INR 525,000 ($6323.7138) for digital scope. The cost per case for reusable scope is calculated by dividing the mean cost of FU by the mean number of cases done. The reprocessing cost of INR 527 was then added. Thus, the average cost per procedure for fiberoptic and digital FU was INR 2658.76 and INR 7089.50, respectively. We compared this cost with a projected cost of disposable FUbased on today's market data, which ranged from INR 60,000 to 107,427.

Conclusions

The reusable scopes are durable, cost-effective, and an excellent option for high case-load institutions.

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

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

Ureteroscopic lithotripsy with pressure-measuring ureteral access sheath for large ureteral stones

INTRODUCTION

To evaluate the safety and efficacy of ureteroscopic lithotripsy with pressure-measuring ureteral access sheath (PM-UAS) for large ureteral stones.

MATERIAL AND METHODS

A total of 258 consecutive patients with large ureteral stones ≥15 mm was enrolled. They were treated by ureteroscopic lithotripsy with PM-UAS in the oblique supine lithotomy position. The technology can precisely monitor and automatically control cavity pressure. The cavity pressure control value was set at -15 mmHg∼-5 mmHg. The cavity pressure limit value was set at 30 mmHg. Infusion flow rate was set at 100-200 ml/min. Postoperative data such as stone-free rate and complications were analyzed.

RESULTS

PM-UAS was successfully implanted in 225 patients at one stage. Eighteen cases of patients who had failed the first surgery were successfully treated with a second operation. Fifty-one cases with stones migrating up to the kidney were converted to flexible lithotripsy. The other 15 cases were converted to percutaneous nephrolithotomy due to significant ureteral stenosis. The operative time was 49.5 ± 11.2 min. The stone-free rates after one month and three months were 87.2% (212/243) and 94.2% (229/243), respectively. Complications from grade I to II were observed in 25(10.3%) patients. No other complications from grade III to V were noted.

CONCLUSION

The ureteroscopic lithotripsy with PM-UAS is safe and efficacious for large ureteral stones.

Scoping Review of Experimental and Clinical Evidence and Its Influence on Development of the Suction Ureteral Access Sheath

The ureteral access sheath (UAS) has been a boon and a bane in flexible ureteroscopy (FURS), with its merits and demerits well established. Its design and dimensions were instrumental in reshaping the way flexible scopes were used and were key adjuncts to establishing retrograde intrarenal surgery (RIRS) as a standard of care in the endourological management of renal stones. With the ever-changing landscape of RIRS over the decades shaped by technological advancements in lasers and flexible scopes, the UAS has also continuously evolved. The utility of suction in endourology has recently changed the way RIRS is performed and is a game changer for FURS outcomes. With strong clinical and experimental evidence to support its use, the UAS has undergone a transformative change in the recent past, with its ability to monitor intrarenal pressure and provide a superior vacuum-cleaner effect that improves the trifecta of RIRS, namely an improved single-stage stone-free rate (SFR), minimise complications, and reduce reinterventions. Our comprehensive review outlines the key clinical and experimental evidence and traces the developments that were key to modifying the traditional UAS into a flexible and navigable suction ureteric access sheath (FANS) and highlights how the design and modifications, in turn, influence the ability to push the boundaries of RIRS.

The Effect of Ureteral Access Sheath Use/Caliber Change on Outcomes of Retrograde Intrarenal Surgery, Short-Term Kidney Functions, Radiation Exposure, Ureteroscope Lifetime, and Factors Predicting Insertion Failure: A RIRSearch Study

Background: The aim of this study was (1) to explore effect of ureteral access sheath (UAS) use on primary retrograde intrarenal surgery (RIRS) outcomes, short-term kidney functions, radiation exposure, and ureteroscope lifetime (URS-LT) and (2) to reveal factors that predict UAS insertion failure. Materials and Methods: Patients (n = 1318) who underwent RIRS without UAS (Group 1), those who had operation with a <11-13 Fr (Group 2), and those with a ≥11-13 Fr UAS were matched (1:1:2) and compared. Stone-free rate (SFR), intra- and postoperative complications, acute kidney injury (AKI), fluoroscopy time, URS-LT, and UAS insertion failure were the outcomes. Results: SFR, which was highest in Group 3 (75%, 71% and 87.3%, respectively; P = .001), was significantly associated with use of ≥11-13 Fr (odds ratio [OR]: 4.2, P < .001), but was not with use of <11-13 Fr UAS (OR: 1.3, P = .3). Group 3 had less need for auxiliary procedure (15%, 16%, and 7.4%, respectively; P = .03). Five percent of patients had a risk of AKI, but only 0.3% developed AKI. Although UAS use was protective against creatinine increase (OR: 0.65, P = .02), increased risk of AKI was only associated with female gender (OR: 5.5, P < .001). Fluroscopy times were 5, 15, and 87 sn, respectively (P < .001). Short URS-LT was strongly associated with high frequency of lower calix stones (r = -0.94, P = .005), but URS-LT was not correlated with sheathless case rate (r = 0.59, P = .22). UAS insertion success in first attempt was more likely in younger (OR: 0.99, P = .03), hydronephrotic (OR: 3.4, P < .001), and female cases (OR: 1.5, P = .008). But absolute UAS insertion failure was associated with female gender (OR: 2.7, P = .017). Conclusions: Not any UAS use but a higher caliber UAS use may improve SFR and protect against AKI after RIRS. Although UAS insertion failure is seen mostly in men, it may be more challenging in women owing to less efficacy of preoperative Double-J stent.

Breakage Costs in Flexible Ureteroscopy: Digital vs. Fiberoptic Modalities

OBJECTIVE

To compare the maintenance costs of digital flexible ureteroscopes (DFU) versus fiberoptic flexible ureteroscopes (FFU) to understand the long-term financial impact associated with breakage in a flexible ureteroscopy (f-URS) program.

METHODS

Data for breakage of FFU and DFU at an academic institution from 2019 to 2021 were obtained from our vendor (Karl Storz) and analyzed by month. Correlation test was used to evaluate significant differences in number of procedures, number of breakage events, breakage rates, and repair cost per month. Cumulative analyses were utilized to examine the number of procedures before failure (time to failure - TTF) and repair costs per procedure (RCpP).

RESULTS

We performed a total of 2,154 f-URS, including 1,355 with FFU and 799 with DFU (P<.001). Although we found a higher number of breakage events in FFU (n=124) than DFU (n=73) (P<.001), the overall breakage rate was similar, 9.9% vs. 8.8%, respectively (P=0.86). On cumulative analysis, both modalities reached the same TTF plateau (11 cases) after 18 months. After 400 cases, the RCpP for DFU was 1.25 times higher than for FFU (P=0.04).

CONCLUSION

Overall, we found no difference in overall scope breakage rates between DFU and FFU. Although there was no difference in TTF over time, at the beginning DFU displayed considerable higher durability, leading to lower RCpP. Furthermore, DFU's endurance leveled off to FFU over time, resulting in higher RCpP after 400 cases. This finding may be explained by the presence of renewed scopes after repair.

Image Distortion During Flexible Ureteroscopy: A Laboratory Model Comparing Super Pulsed Thulium Fiber Laser vs High-Power Ho:YAG Laser

Purpose: Digital ureteroscopes employ "chip-on-the-tip" technology that allows for significant improvement in image resolution. However, image distortion often occurs during laser lithotripsy owing to acoustic wave production. We sought to compare image distortion using different laser power settings and distances from the laser fiber tip to the scope for the Super Pulsed Thulium Fiber (SPTF) laser and high-power Holmium:YAG (Ho:YAG) laser. Materials and Methods: Ureteroscopy was simulated using a silicon kidney-ureter-bladder model fitted with a 12F/14F access sheath and the Lithovue™ (Boston Scientific), disposable digital flexible ureteroscope. At defined laser parameters (10, 20, 30 and 40 W, short pulse), a 200-μm laser fiber was slowly retracted toward the tip of the ureteroscope during laser activation. Image distortion was identified, and distance from the laser tip to the scope tip was determined. Data from the two lasers were compared utilizing t-tests. Results: After controlling for frequency, power, and laser mode, utilizing 1.0 J of energy was significantly associated with less feedback than 0.5 J (-0.091 mm, p ≤ 0.05). Increased power was associated with larger feedback distance (0.016 mm, p ≤ 0.05); however, increase in frequency did not have a significant effect (-0.001 mm, p = 0.39). The SPFT laser had significantly less feedback when compared with all Holmium laser modes. Conclusions: Increased total power results in image distortion occurring at greater distances from the tip of the ureteroscope during laser activation. Image distortion occurs further from the ureteroscope with Ho:YAG laser than with SPTF fibers at the same laser settings. In clinical practice, the tip of the laser fiber should be kept further away from the tip of the scope during ureteroscopy as the power increases as well as when utilizing the Ho:YAG system compared with the SPTF laser platform. The SPTF laser may have a better safety profile in terms of potential scope damage.

Hybrid flexible ureteroscopy strategy in the management of renal stones - a narrative review

The introduction of single-use flexible ureteroscopes (suFURSs) in daily practice tends to overcome the main limitations of reusable ureteroscopes (reFURSs), in terms of high acquisition costs, maintenance, breakages and repairing costs, reprocessing and sterilization, as retrograde intrarenal surgery (RIRS) is promoted as first-line treatment of renal stones in most cases. A hybrid strategy implies having both instruments in the armamentarium of endourology and choosing the best strategy for cost-efficiency and protecting expensive reusable instruments in selected high-risk for breakage cases such as large stones of the inferior calyx, a steep infundibulopelvic angle or narrow infundibulum, or abnormal anatomy as in horseshoe and ectopic kidney. In terms of safety and efficiency, data present suFURSs as a safe alternative considering operating time, stone-free, and complication rates. An important aspect is highlighted by several authors about reusable instrument disinfection as various pathogens are still detected after proper sterilization. This comprehensive narrative review aims to analyze available data comparing suFURSs and reFURSs, considering economic, technical, and operative aspects of the two types of instruments, as well as the strategy of adopting a hybrid approach to selecting the most appropriate flexible ureteroscope in each case.

Flexible ureteroscopy without ureteral access sheath

INTRODUCTION

Ureteral access sheath (UAS) is widely used in flexible ureteroscopy and laser lithotripsy (FURS) based on better stone-free rates, lower intrarenal pressure and fewer complications. However, it also rises surgical costs and may injure the ureteral wall. The main objective of our study is to compare safety and efficacy of FURS with and without UAS to evaluate whether its use is justified in all cases.

MATERIALS AND METHODS

We performed a retrospective observational analytic study based on a prospective database. A total of 241 consecutive patients who underwent FURS for upper ureter and renal stones between January 2018 and May 2020 were included for analysis and divided into two groups upon UAS use. We compared demographic data, stone characteristics, prestenting, operative time, need for ureteral stent, postoperative urinary tract infection, renal colic and need for ancillary procedures.

RESULTS

A total of 198 patients (82.2%) were included in the group without UAS. Operative time was significantly shorter in the group of patients without UAS than those with UAS (64.6 minutes ± 29.5 vs. 89.9 minutes ± 2.8 respectively; p 0.010). Both groups had similar rates of colic pain and urinary tract infection. Ancillary procedures were more frequent in the UAS group (37.2 vs. 21.2%; p 0.026), but significance was lost in multivariate assessment.

CONCLUSION

FURS without UAS seems to be as safe as FURS with UAS but requires less ancillary procedures. An additional advantage is shorter operative time.

Repair Rate and Associated Costs of Reusable Flexible Ureteroscopes: A Systematic Review and Meta-analysis

Context

The refined mechanics of a flexible ureteroscope (fURS) are vulnerable to damage. Sending the fURS for repair is costly and has driven interest toward estimating the resources used for fURS repairs.

Objective

To systematically review available literature and to estimate the total weighted repair rate of an fURS and the average repair cost per ureteroscopy.

Evidence acquisition

A systematic review was conducted by searching the MEDLINE, Embase, Web of Science, and Cochrane Library databases. The average costs of all repairs identified in the included studies were extracted. A random-effect model was used to calculate the pooled total fURS repair rate. The total weighted repair rate and average cost per repair were multiplied to provide an average cost of repair per ureteroscopy procedure.

Evidence synthesis

We identified 18 studies that fulfilled the inclusion criteria, which included 411 repairs from 5900 investigated ureteroscopy procedures. The calculated weighted repair rate was 6.5% ± 0.745% (95% confidence interval: 5.0–7.9%; I² = 75.3%), equivalent to 15 ureteroscopy procedures before repair. The average cost per repair was 6808 USD; according to the weighted repair rate of 6.5%, this corresponds to an average repair cost of 441 USD per procedure. Egger’s regression test did not reveal a significant publication bias (p = 0.07).

Conclusions

This is the first meta-analysis to estimate the repair rate of the fURS used for ureteroscopy. Our analysis demonstrates a repair rate of 6.5%, equivalent to 15 ureteroscopy procedures between fURS repairs and a repair cost of 441 USD per procedure. Ureteroscopy practices should consider fURS breakage rates and repair costs to optimize the use of reusable versus disposable devices.

Patient summary

We reviewed available literature investigating the repair rate of a flexible ureteroscope (fURS). We found that fURSs are sent for repair after every 15 ureteroscopy procedures, corresponding to 441 USD per procedure in repair cost.

Understanding Ureteral Access Sheath Use Within a Statewide Collaborative and Its Effect on Surgical and Clinical Outcomes

Introduction: Ureteral access sheaths (UASs) are frequently used during ureteroscopy (URS), but their use is not without potential risk. We investigated patterns of UAS use and associated outcomes across practices in Michigan within a quality improvement collaborative. Methods: The Michigan Urological Surgery Improvement Collaborative (MUSIC) Reducing Operative Complications from Kidney Stones (ROCKS) initiative maintains a web-based, prospective clinical registry of patients undergoing URS for urinary stone disease (USD). We analyzed all patients undergoing primary URS for renal and ureteral stones from June 2016 to July 2018 in the ROCKS registry. We determined rates of UAS usage across practices and associated outcomes, including 30-day emergency department (ED) visits and hospitalization, as well as stone-free rates. Using multivariate logistical regression, we determined the predictors of UAS use as well as outcomes, including stone-free rates, ED visits, and hospitalizations, associated with UAS use. Results: Of the 5316 URS procedures identified, UASs were used in 1969 (37.7%) cases. Stones were significantly larger and more likely to be located in the kidney in cases with UAS use. UAS use during URS varied greatly across practices (1.9%-96%, p < 0.05). After adjusting for clinical and surgical risk factors, UAS use significantly increased the odds of postoperative ED visits (odds ratio [OR] = 1.50, 95% confidence interval [CI] 1.17-1.93, p < 0.05) and hospitalization (OR = 1.77, 95% CI 1.22-2.56, p < 0.05) as well as decreased the odds of being stone free (OR = 0.75, 95% CI 0.57-0.99, p < 0.05). Conclusions: In the current study, UAS use during URS for USD was not associated with an increased likelihood of being stone free; moreover, it increased the odds of a postoperative ED visit and or hospitalization. Our findings demonstrate that UAS use is not without risk and should be employed judiciously.

The effect of laser fiber on the damage of the working channel of a flexible ureteroscope

INTRODUCTION

Flexible ureteroscopy involves expensive equipment that is expensive to repair. This study aimed to investigate the effects of cleavage by various tools on the laser fiber tip and to determine the extent of damage incurred to the laser passing through the working channel and firing at different degrees of deflection.

MATERIALS AND METHODS

We investigated the effect of cleavage on Lumenis Slimline reusable fibers (272 and 365 μm) as performed by four cleavage tools: a scribe pen, a surgical blade, suture scissors, and ceramic scissors. Following cleavage, we recorded the pattern of light dispersion and power output. The laser fibers passed through the working channel at various.

RESULTS

The ceramic scissors provided the best pattern of light dispersion and the highest power output. The suture scissors provided unacceptable levels of light dispersion. The 272 μm fiber was able to pass through the working channel at 30 and 45 degrees of deflection. The 365 μm laser fiber was only able to pass through the working channel at 30 degrees of deflection. There was no breakage of the laser fiber at any of the degrees of deflection evaluated.

CONCLUSIONS

Analysis showed that the ceramic scissors were the best tool for cleaving Lumenis Slimline reusable fibers and that suture scissors were unacceptable. We also found that the deflection angle that causes damage to the working channel by laser insertion is dependent on both the size of the laser fiber and the degree of bending. Firing the laser during scope deflection could be performed safely at any degree of deflection, even with a high laser power of 40 W for a duration of 30 s.

Cost comparison of single-use versus reusable flexible ureteroscope: A systematic review

Single-use flexible ureteroscopes (su-fURS) aim at overcoming the main limitations of conventional reusable flexible ureteroscopes (re-fURS) in terms of acquisition and maintenance costs, breakages, and reprocessing. We aimed to perform a literature review on available re-fURS and su-fURS performances with a focus on costs. A search of Medline, EMBASE, CINAHL, and Scopus databases was performed to identify articles published in English within the last 10 years addressing refURS and su-fURS characteristics, clinical, and cost data. Relevant studies were then screened, and the data were extracted, analyzed, and summarized. The Preferred Reporting Items for Systematic Reviews and Meta-analysis criteria were applied. A narrative synthesis was performed. To date, few studies have properly investigated the issue of costs in ureteroscopy. An important local and international variation in costs exists for both re-fURS and su-fURS in terms of acquisition, maintenance, and repair costs. Reusable scopes have high acquisition and ancillary (e.g. repair, involved personnel) costs, which are not considered in a pure su-fURS activity. However, only recently su-fURS were shown to have a similar efficacy as compared with reusable devices. In high-volume centers, with proper training for reusable ureteroscopes management, the cost per case of reusable and single-use scopes are overlapping ($1,212-$1,743 versus $1,300-$3,180 per procedure). There is a partial overlap in the ranges of costs for single-use and reusable scopes, which makes it important to precisely know the caseload, repair bills, and added expenses when negotiating purchase prices, repair prices, and warranty conditions for scopes.

Failure of ureteral access sheath insertion in virgin ureters: A retrospective tertiary care center study

Objective:

The objective of the study was to identify the failure rate of insertion of ureteral access sheath (UAS) during primary flexible ureteroscopy (FURS).

Materials and Methods:

This was a single-surgeon, single-tertiary care center retrospective study. All patients who underwent primary FURS for proximal ureteric or renal stones from November 2014 to May 2018 were included in the study. Patients with a stone burden of more than 20 mm were excluded from the study. A 10/12-Fr coaxial UAS (Bi-Flex, Rocamed) was used. Data collection included age, sex, body mass index (BMI), stone burden and location, previous spontaneous passage of stones, type of anesthesia, and preexisting congenital anomalies. The Chi-square test and t-test were used for the statistical analyses.

Results:

One hundred and twelve patients were included in the study. All patients underwent primary FURS. The failure rate of primary UAS insertion was 10.7% (n = 12). No statistically significant difference was found in age, BMI, type of anesthesia, previous history of spontaneous stone passage, and stone burden between the success and failure groups (P > 0.05).

Conclusions:

We believe that our study opens the door for a multicentric prospective trial. Identifying factors leading to a failed primary FURS and UAS insertion is crucial to properly counsel patients preoperatively about the number of procedures that they might need and to prevent the financial loss associated with failed UAS insertion.

Impact of ureteral access sheath on renal stone treatment: prospective comparative non-randomised outcomes over a 7-year period

PURPOSE

To compare the outcomes (stone free rate and complications) of renal stone treatment with and without the use of ureteral access sheath (UAS). The worldwide use of UAS has risen over the last decade; however, questions still remain on the safety and outcomes with its use. We wanted to look at the role of UAS for treatment of consecutive renal stones over a 7-year period.

METHODS

The outcomes of flexible ureteroscopy and stone treatment (FURS) for renal stones with and without the use of UAS was prospectively compared from March 2012 to July 2018. Patients were divided into two groups: group-1 where UAS was used for stone treatment and group-2 where a UAS was not used. Data were collected prospectively on consecutive patients for demographics, stone size, location and number, pre and post-operative stent usage, operative time duration, stone free rate (SFR), length of stay and complications.

RESULTS

During the study period, 338 patients underwent FURS for renal stones, of which a UAS was used for 203 (60%) patients. The mean age of patients was 56 years (range 2-89 years) with a male:female ratio of 204:134. The mean cumulative stone size and the mean number of stones was 16.5 ± 10.8 mm and 11.37 ± 8.08 mm (P < 0.001), and 2.17 ± 1.99 and 1.66 ± 1.50 (P = 0.009) for groups 1 and 2 respectively. The pre and post-operative stent insertion rates were similar in the two groups. The procedural time was longer in group-1 (54.8 ± 25.8 min) compared to group-2 (41.3 ± 22.2 min) (P < 0.001). The SFR for group-1 (88%) was slightly lower than group-2 (94%) although this was not statistically significant (P = 0.07). There were no intra-operative complications in either of the groups. Post-operative complications were seen in eight patients in group-1 (7 Clavien I/II and 1 Clavien IVa) and two patients in group-2 (Clavien I) (P = 0.19).

CONCLUSION

The use of UAS for renal stones is safe with no intra-operative complications noted in our series. Good stone-free rates were obtained for large and multiple renal stones with a small risk of minor complications post-operatively.

Laser fibre, rather than the stone, may harm the scope: retrospective monocentric analysis of 26 pre- and intraoperative factors of flexible ureteroscope (fURS) damage

PURPOSE

The increasing number of flexible ureteroscopy procedures, the fragility of devices and their repair costs are a burden for urological departments worldwide. The objective was to investigate the impact of 26 pre- and intraoperative factors on reusable flexible ureteroscope (fURS) damage.

METHODS

All procedures were conducted with reusable fURS: Karl Storz Flex-X2 or Olympus URF-V. Statistical analysis was performed in RStudio (1.0.136) with Chi-square test and Mann-Whitney U tests (MWU).

RESULTS

In total, 416 flexible ureteroscopies, performed between September 2013 and June 2017, were analysed. 283 (68.03%) of these were for kidney stone surgery, and 133 (31.97%) for diagnostic purposes. In total, 39 (9.38%) devices were postoperatively deemed defective. The application of reusable laser fibre through fURS was more common in cases with documented defects [17/39 (43.59%) vs. 102/377 (27.06%), p = 0.047]. Other factors such as application of nitinol basket, biopsy via fURS, insertion of access sheath (UAS), as well as stone burden [median kidney stone maximal diameter: 6 mm (min 2.0; max 30.0) vs. 6 mm (min 1.0 vs. max 30.0)] showed no influence on fURS damage rate (p > 0.05). The infundibulopelvic angle (IPA) was steeper in cases with fURS damage as compared to cases without damage [median 44.0° (min 20.0; max 81.0) vs. 55.0 (min 7.0; max 122.0), p < 0.001].

CONCLUSIONS

Application of laser fibre via fURS can be considered as a risk factor of fURS damage. Stone burden, as well as the usage of not-sharp ended devices as nitinol baskets or forceps, is primarily not responsible for fURS damage.

A comprehensive literature-based equation to compare cost-effectiveness of a flexible ureteroscopy program with single-use versus reusable devices

PURPOSE

To critically review all literature concerning the cost-effectiveness of flexible ureteroscopy comparing single-use with reusable scopes.

MATERIALS AND METHODS

A systematic online literature review was performed in PubMed, Embase and Google Scholar databases. All factors potentially affecting surgical costs or clinical outcomes were considered. Prospective assessments, case control and case series studies were included.

RESULTS

741 studies were found. Of those, 18 were duplicated and 77 were not related to urology procedures. Of the remaining 646 studies, 59 were considered of relevance and selected for further analysis. Stone free and complication rates were similar between single-use and reusable scopes. Operative time was in average 20% shorter with digital scopes, single-use or not. Reusable digital scopes seem to last longer than optic ones, though scope longevity is very variable worldwide. New scopes usually last four times more than refurbished ones and single-use ureterorenoscopes have good resilience throughout long cases. Longer scope longevity is achieved with Cidex and if a dedicated nurse takes care of the sterilization process. The main surgical factors that negatively impact device longevity are lower pole pathologies, large stone burden and non-use of a ureteral access sheath. We have built a comprehensive fi nancial costeffective decision model to fl exible ureteroscope acquisition.

CONCLUSIONS

The cost-effectiveness of a fl exible ureteroscopy program is dependent of several aspects. We have developed a equation to allow a literature-based and adaptable decision model to every interested stakeholder. Disposable devices are already a reality and will progressively become the standard as manufacturing price falls.

Handling and protecting your flexible ureteroscope: how to maximise scope usage

Flexible ureteroscopy is an important therapeutic and diagnostic procedure and has seen rapid rise in its utilisation in recent years. There have been numerous developments in flexible ureteroscope (fURS) technology but scope fragility, and the associated high maintenance costs, remains a concern. A comprehensive Medline search for related publications from the last 20 years was undertaken to identify common causes of fURS damage and ascertain practices to minimise this. Flexible ureteroscopy can be due to intraoperative causes (loss of the deflection mechanism, damage to the working channel due and fibreoptic bundle injury) and non-operative damage which occur during cleaning, sterilisation and handling of the fURS. The review summarises the available literature to help highlight common mechanisms of scope damage, and outlines evidence-based measures to reduce the risk of damage and maximise durability. Scope fragility remains a problem with significant associated cost implications. In a culture of rising fURS use and reducing re-imbursement for endourologists, prolonging the longevity of the fURS is imperative for maintaining profitability. There are simple and inexpensive practices which can be immediately adopted to maximise fURS use and reduce the need for repairs.

Can alpha blockers facilitate the placement of ureteral access sheaths in retrograde intrarenal surgery?

OBJECTIVE

To investigate the effects of alpha blocker treatment on the placement of ureteral access sheaths (UAS) during retrograde intrarenal surgery (RIRS).

MATERIAL AND METHODS

This study was a retrospective analysis of prospectively collected data. Patients who underwent RIRS due to renal stones between November 2015 and December 2017 were seperated into two groups. Age, gender, body mass index (BMI), stone size, laterality, hydronephrosis degree, and renal stone density were recorded. Tamsulosin (0.4 mg/day) was prescribed to the study group (n=25) 2 weeks before the operation. The control group (n=25) underwent the operation without any additional treatment. All the operations were performed using a 7.5 Fr flexible ureteroscope and 9.5/11.5 Fr (Cook, Blooming, USA) UAS.

RESULTS

Two patients in the study group were excluded from the study as they suffered from dizziness and retrograde ejaculation. No statistically significant difference was found between the patients in the study group (n=23) and control group (n=25) in terms of age, gender, BMI, stone size, laterality, hydronephrosis, and renal stone density (p=0.470, p=0.536, p=0.456, p=0.102, p=0.555, p=0.732, and p=0.317, respectively). The UAS could be successfully placed on the first attempt in 15 (65.2%) patients in the study group and 11 (44%) patients in the control group during the first attempt itself. Even though the successful UAS placement rate was higher in the study group, no statistically significant values were observed (p=0.141).

CONCLUSION

The data obtained from the present study showed that the use of alpha blockers prior to RIRS did not improve the UAS placement rates. It is considered that studies conducted on more patients might be able to achieve significant values.

Surgical technique to achieve high durability of flexible ureteroscopes: A single hospital experience

Background

To describe a novel operative technique resulting in extended durability and improved ease of use of current flexible ureteroscopes (FURS). A surgical method employing a modified technique of using an Olympus digital flexible URF-V ureteroscope was developed.

Methods

We retrospectively studied 546 patients who underwent retrograde intrarenal surgery (RIRS) using this modified approach performed by a single surgeon at our hospital, and investigated the outcome and durability of the ureteroscope.

Results

Through the study period, the URF-V ureteroscope required repair five times in total. During factory maintenance, distal working channel damage was noted twice, and outer bending rubber damage was noted once. The most recent two repairs were required due to laser penetration. Despite the damage and repairs, the deflection system was almost entirely intact after high-frequency use. The durability of FURS determines the efficacy of RIRS for renal stones.

Conclusion

In this report, we described our modified upside-down technique for manipulation of FURS under unequal dual deflection in order to preserve the deflection apparatus, which yielded a greatly prolonged durability. Additionally, the use of mimic drive turning decreased the time needed to train urologists.

Basal-bolus or premixed? Shedding light on optimal insulin regime for type 1 diabetes

In this issue of the Biomedical Journal, we highlight original research that will help to guide the choice of insulin administration regimes for children with type 1 diabetes. We also investigate whether a common medication for attention deficit/hyperactivity disorder worsens sleep problems among these children, and discover a new approach to maximize the lifetime of a fragile piece of surgical equipment.

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.

Ureteral access sheaths: a comprehensive comparison of physical and mechanical properties

Introduction:

Ureteral access sheaths (UAS) facilitate flexible ureteroscopy in the treat- ment of urolithiasis. The physical properties of UAS vary by manufacturer and model. We compared three new UAS: Glideway (GW, Terumo, 11/13Fr, 12/14Fr), Pathway (PW, Terumo 12/14F) and Navigator HD (NHD, Boston Scientific, 11/13Fr, 12/14Fr) in the domains of safety characteristics, positioning characteristics, lubricity and radio- opacity.

Materials and Methods:

In vitro testing of the three UAS included safety testing-tip perforation force, sheath edge deformation and dilator extraction forces. Positioning characteristics tested included tip bending, stiffness (resistance to coaxial buckling forces), kinking (resistance to perpendicular forces), and insertion forces. Lubricity was assessed by measured frictional forces of the outer sheath. Finally, radio-opacity was tested utilizing fluoroscopic imaging of the three 12F sheaths and inner dilators.

Results:

The PW (0.245 lb) and GW (0.286 lb) required less force for tip perforation compared to the NHD (0.628 lb). The NHD sheath edge deformation was mild compared to more severe deformation for the PW and GW. The PW (1.008 lb) required greater force than the GW (0.136 lb) and NHD (0.043 lb) for inner dilator removal. The GW (3.69 lbs) and NHD (4.17 lb) had similar inner dilator tip stiffness when bent, while the PW had the weakest inner dilator tip, 1.91 lbs. The PW (0.271 lb) was most susceptible to buckling and kinking (1.626 lb). The most lubricious UAS was the NHD (0.055 lbs for 12F). The NHD (0.277 lbs) required the least insertional force through a biological model and possessed the greatest radio-opacity.

Conclusions:

Comparison of different commercially available UAS in various sizes reveals that there are mechanical differences in sheaths that may play a role clinically. The Terumo sheaths' (GW and PW) were outperformed by the Boston Scientific NHD in simulating safety, ease of use and radio-opacity.

Systematic review of ureteral access sheaths: facts and myths

The aim of the present paper was to review the literature on all available ureteral access sheaths (UASs) with their indications, limitations, risks, advantages and disadvantages in current modern endourological practice. Two authors searched Medline, Scopus, Embase and Web of Science databases to identify studies on UASs published in English. No time period restriction was applied. All original articles reporting outcomes or innovations were included. Additional articles identified through references lists were also included. Case reports, editorials, letters, review articles and meeting abstracts were excluded. A total of 754 abstracts were screened, 176 original articles were assessed for eligibility and 83 articles were included in the review. Based on a low level of evidence, UASs increase irrigation flow during flexible ureteroscopy and decrease intrapelvic pressure and probably infectious complications. Data were controversial and sparse on the impact of UASs on multiple reinsertions and withdrawals of a ureteroscope, stone-free rates, ureteroscope protection or damage, postoperative pain, risk of ureteral strictures, and also on its cost-effectiveness. Studies on the benefit of UASs in paediatrics and in patients with a coagulopathy were inconclusive. In the absence of good randomized data, the true impact of UASs on surgery outcome remains unclear. The present review may contribute to the evidence-based decision-making process at the individual patient level regarding whether or not a UAS should be used.

Steep Infundibulopelvic Angle as a New Risk Factor for Flexible Ureteroscope Damage and Complicated Postoperative Course

OBJECTIVE

The increasing number of flexible ureterorenoscopy (fURS) procedures, the fragility of devices, and their growing repair costs represent a substantial burden for urological departments worldwide. No risk factors of flexible ureteroscope damage have been identified so far. The objective of this study was to investigate the impact of infundibulopelvic angle (IPA) on device damage and on other intraoperative and postoperative factors such as length of hospital stay, surgical complications, stone-free rate (SFR), operation, and fluoroscopy time.

MATERIALS AND METHODS

In a retrospective monocentric study, IPA was measured based on intraoperative retrograde pyelography images taken during fURS. All procedures were conducted with modern reusable flexible ureteroscopes: Karl Storz Flex-X2 or Olympus URF-V. Statistical analysis was performed in RStudio (version 1.0.136) with the unpaired t-test and Mann-Whitney U test. Pearson correlation coefficient (Pearson's r) was measured whenever applicable.

RESULTS

In total, 381 fURS performed between September 2013 and March 2017 were analyzed: 260 (68.24%) for kidney stone operation and 121 (31.76%) for diagnostic purposes; of these, 38 (9.97%) devices were postoperatively deemed defective. IPA values were significantly steeper in cases with flexible ureteroscope damage compared to cases without damage (median 42.5 degrees vs 56.0, p < 0.001). Steeper IPA was significantly associated with the occurrence of Clavien-Dindo ≥2 complications (median 51.0 degrees vs 55.0, p = 0.005) as well as prolonged hospital stay (median 51.0 degrees vs 55.0, p = 0.014). No influence on SFR was observed (p > 0.05). IPA did not correlate with operation or fluoroscopy time.

CONCLUSIONS

Steep IPA can be considered the first risk factor predicting both flexible ureteroscope damage and an unfavorable postoperative course. A better understanding of damage mechanisms is the key for the proper indications to use costly single-use devices.

Identifying factors associated with need for flexible ureteroscope repair: a Western Endourology STone (WEST) research consortium prospective cohort study

Maintenance of flexible ureteroscopes can involve high costs and administrative burden. Instrument fragility necessitates eventual repair, rendering scopes inaccessible during refurbishment. We conducted a multi-institutional prospective cohort study to identify perioperative factors influencing flexible ureteroscope durability. Patients undergoing flexible ureteroscopy (URS) at six United States endourology centers were enrolled between August 2014 and June 2015. Surgeon self-reported concern and satisfaction with scope performance as well as upward and downward angles of deflection for each scope tip were measured before and after each procedure. The need for scope repair was determined by the operating surgeon at the time of the procedure and recorded. 424 URS cases using 74 flexible ureteroscopes were identified. Scope repair was required in 28 cases (6.6%) involving 26 scopes (35.1%). Upon univariate analysis, shorter patient height, absence of guidewire use, presence of a ureteral access sheath (UAS), longer procedure time, larger stone size, lithotrite type, surgeon training level, and self-reported concern were associated with scope repair. Upon multivariate analysis, UAS use (OR = 2.53, p = 0.005) and degree loss of scope upward flexion during a case (OR = 1.02, p = 0.03) increased the odds of a scope needing repair while the use of safety guidewire decreased the odds of a scope repair (OR = 0.50, p = 0.045). Lithotrite use and surgeon concern were associated with degree loss of scope upward flexion. The use of a UAS, absence of a safety guidewire, and the loss of upward ureteroscope flexion should be considered when evaluating means of optimizing reusable ureteroscope durability.

Single-use flexible ureteropyeloscopy: a systematic review

PURPOSE

Data assessing the effectiveness of single-use flexible ureteropyeloscopy (FURS) are limited. This study evaluates and compares single-use FURS with conventional reusable FURS.

METHODS

A systematic search using electronic databases (Pubmed and Embase) was performed for studies evaluating single-use FURS in the setting of urinary tract stone disease. Outcome measures included a comparative evaluation of their mechanical, optical and clinical outcomes.

RESULTS

Eleven studies on 466 patients met inclusion criteria. In vitro comparative data were available on three single-use flexible ureteropyeloscopes (LithoVue™, Polyscope™ and SemiFlex™) and clinical data were available on two (LithoVue™ and Polyscope™). The overall stone-free rate and complication rate associated with single-use FURS was 87 ± 15% and 9.3 ± 9%, respectively. There were no significant differences in procedure duration, stone size, stone clearance and complication rates when single-use FURS and reusable FURS were compared (duration: 73 ± 27 versus 74 ± 13 min, p = 0.99; stone size: 1.36 ± 0.2 versus 1.34 ± 0.18 cm, p = 0.93; stone-free rate: 77.8 ± 18 versus 68.5 ± 33%, p = 0.76; complication rate 15.3 ± 10.6 versus 15 ± 1.6%, p = 0.3).

CONCLUSIONS

Single-use FURS demonstrates comparable efficacy with reusable FURS in treating renal calculi. Further studies on clinical efficacy and cost are needed to determine whether single-use FURS will reliably replace its reusable counterpart.

Retrospective Cost Analysis of a Single-Center Reusable Flexible Ureterorenoscopy Program: A Comparative Cost Simulation of Disposable fURS as an Alternative

OBJECTIVE

The increasing number of flexible ureterorenoscopy (fURS) procedures, the fragility of devices, and their growing maintenance and repair costs represent a substantial burden for urologic departments. Disposable single-use fURS devices offer many advantages over reusable fURS. Among them, the LithoVue™ model shows the best clinical utility. In our study, we assessed the economic aspects of reusable fURS application compared with the potential costs and benefits of single-use fURS (LithoVue™). Indications for single-use fURS were proposed based on potential risk factors of reusable fURS damage.

MATERIALS AND METHODS

This single-center retrospective analysis compared the actual cost of reusable fURS procedures with the potential costs of LithoVue™ based on the price offered by the manufacturer. Consecutive case analysis of damaged fURS was performed to determine potential risk factors associated with fURS damage.

RESULTS

The study group consisted of 423 reusable fURS procedures conducted between January 2013 and December 2016. During this period, 102 (24.11%) diagnostic fURS and 321 (75.89%) fURS for kidney stone therapy were performed. In 32 of 423 (7.57%) fURS cases, devices were postoperatively deemed defective, 9 of which were used for diagnostic procedures (9/102; 8.82%), 7 for stone removal (7/148; 4.73%), and 16 for stone removal and laser (Ho:YAG) application (16/173; 9.25%). The average cost per reusable fURS procedure was found to be €503.26.

CONCLUSIONS

Disposable fURS is a more expensive option for high-volume centers. Based on our case analysis, laser disintegration treatment of multiple, large stones in the lower kidney pole of recurrent stone formers, as well as a steep infundibulopelvic angle (IPA ≤50°), seems to be the main risk factor for fURS damage. For these cases, disposable fURS may be a cost-effective alternative; however, a prospective comparison of economic outcomes between disposable and reusable fURS, together with confirmation of the proposed damage risk factors, is needed.

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.

Laser Fiber and Flexible Ureterorenoscopy: The Safety Distance Concept

INTRODUCTION

The costs of flexible ureterorenoscopes (fURSs) and their repair oblige the surgeon to know the proper handling of instruments. There is a lack of evidence in the literature about the safety distance that the laser fiber should have once out from the ureterorenoscope to avoid instrumental damages.

MATERIALS AND METHODS

We performed an in vitro observational study. Seven fURSs were tested. The distance from the laser fiber tip and the fURS camera was measured at the first appearance on the endoscopic screen and when the fiber was reaching one-fourth of the screen. Second, to evaluate the impact of the holmium laser bubble according to different fiber distances, an assessment of the size and shape of the bubble created at the tip of the fiber with the laser activated was done, recording the images with a high-speed camera.

RESULTS

The first appearance on the screen of the laser tip is different in different ureterorenoscopes. In all the ureterorenoscopes, we observed that when the laser fiber was at ¼ of the screen, the bubble was never touching the fURS tip.

CONCLUSION

Even if there is a big limitation of this study due to the impossibility to measure and to evaluate the damage of the fURS tip surface, we observed that when the laser fiber tip reaches ¼ of the screen, the bubble generated by laser activation is never rebounding on the camera of the ureterorenoscope, preserving it from laser damages. We can define this position as the safety distance.

To Dust or Not To Dust: a Systematic Review of Ureteroscopic Laser Lithotripsy Techniques

PURPOSE OF REVIEW

This review discusses factors affecting outcomes during ureteroscopy (URS) with laser lithotripsy (LL), explores specific clinical challenges to the efficacy of URS LL, and reviews the available literature comparing the dusting and basketing approaches to URS LL.

RECENT FINDINGS

Data show high stone-free rates with URS LL in all locations of the urinary tract and with all stone types and sizes. Recent data comparing LL with dusting versus basketing suggest higher rates of residual fragments with dusting but less utilization of ureteral access sheaths and potentially shorter operative times. Differences in postoperative complications, re-intervention rates, and other outcome parameters are not yet clear. Interpretation of published data is problematic due to variability in laser settings, follow-up intervals, and definitions for what constitutes stone-free status. URS has overtaken shock wave lithotripsy in the last decade as the most commonly utilized surgical approach for treating urolithiasis. Two primary strategies have emerged as the most common techniques for performing LL: dusting and basketing. There is a relative paucity of data examining the difference in these techniques as it pertains to peri-operative outcomes and overall success. We attempt to synthesize this data into evidence-based and experience-based recommendations.

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.

Digital ureteroscopes: technology update

The field of ureteroscopy has undergone a continual evolution since the first ureteroscopes were introduced. Over the past 10 years, we have entered into the digital era of ureteroscopy with both semirigid and flexible options becoming available. The following review looks at the benefits and drawbacks of digital flexible ureteroscopes as well as the current commercially available options.

First clinical evaluation of a new single-use flexible ureteroscope (LithoVue™): a European prospective multicentric feasibility study

INTRODUCTION

We evaluated a new digital single-use flexible ureteroscope, LithoVue™ with respect to deflection, image quality and maneuverability.

METHODS

A prospective cohort study was conducted in eight tertiary reference centers in Europe in December 2015 and January 2016. All consecutive patients included underwent flexible ureteroscopy and were 18 years or older. Deflection and image quality pre- and post-use and maneuverability were rated with a Likert scale.

RESULTS

A total of 40 procedures were performed (five per institution). The indication for FURS was treatment of renal stones in 92.5 % of the cases. Before LithoVue™ usage, the median measured upward and downward deflections were both 270°. Image quality was rated as "very good" in 65 % of cases and "good" in 30 %. Maneuverability was "very good" in 77.5 % and "good" in 17.5 %. At the final evaluation, median upward and downward deflections were both 270°. Image quality was still "very good" in 65 % of cases and "good" in 30 % with no significant difference compared with preoperative data (p = 1). Maneuverability was "very good" in 72.5 % and "good" in 17.5 %, with no significant difference compared with preoperative data (p = 0.92). Two LithoVue™ broke during surgery (5 %): one occurring in extreme deflection with acute infundibulopelvic angle and spontaneous loss of vision for the second one.

CONCLUSION

The LithoVue™ displayed good image quality, active deflection and maneuverability. Further evaluation of surgical outcomes and cost analysis will help to present the best utility of this single-use FURS in current practice.

Benefits and risks of ureteral access sheaths for retrograde renal access

PURPOSE OF REVIEW

Ureteral access sheath (UAS) became increasingly popular worldwide. However, the safety of its routine use remains controversial. The aim of the current revision is to provide a systematic review on the benefits and disadvantages of the UAS.

RECENT FINDINGS

A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Two reviewers independently searched the literature, finally identifying 20 articles valuable for this review. The use of UAS demonstrated several advantages to facilitate retrograde intrarenal access, lower intrarenal pressure, protect the ureter, protect the scope, and expedite stone extraction. Despite this, there is also some evidence that UAS use may be associated with acute ureteral injury and long-term complications, apparently related to maneuvers for UAS insertion and mucosal or deeper layers of injury and ischemia. Furthermore, there are still pending questions on the possible increase in stone-free rates, and decrease in operative time and costs.

SUMMARY

Although the use of UAS is associated with some risk and limiting factors, it appears from this systematic review that its use is common and safe for the retrograde intrarenal access. Therefore, UAS is highly recommended for the treatment of upper tract disease by means of retrograde intrarenal surgery.

Economic impact of urinary stones

Kidney stones have been rising in prevalence in the United States and worldwide, and represent a significant cost burden. Cost effectiveness research in this area may enable improvements in treatment efficiency that can benefit patients, providers and the healthcare system. There has been limited research in the cost effectiveness of surgical interventions for stone disease, despite the diverse treatment approaches that are available. Medical expulsive therapy (MET) has been shown to improve rates of stone passage for ureteral stones, and there is evidence that this practice should be liberalized from the standpoint of both clinical and cost effectiveness. While conservative treatment following a primary stone event appears to be cost effective, the economic impact of medical therapy for recurrent stone formers requires clarification despite its clinical efficacy. Future study regarding the cost effectiveness of prevention and interventions for stone disease are likely to improve both the quality and efficiency of care.

[Impact of the acquisition of a flexible ureteroscope on the management of upper urinary tract stones in children]

INTRODUCTION

Firstly reported in the early 1990s for the treatment of upper urinary tract stones in adult patients, flexible ureteroscopy (F-URS) has been used in children during the past 10 years and is now considered as a viable, but still second-line alternative to extracorporeal shockwave lithotripsy in these patients (ESWL). The aim of this study was to assess the impact of the acquisition of a F-URS on the management of upper urinary tract stones in children.

PATIENTS AND METHODS

Data of all ESWL, F-URS and percutaneous nephrolithotomy performed for upper urinary tract stones in children from 0 to 18 years old in a single center from 2000 to 2014 have been collected retrospectively. Patients have been divided into two groups: group 1 before the acquisition of the F-URS (2000-2008) and group 2 after the acquisition of the F-URS (2008-2014). Preoperative data and peri-operative outcomes were compared between both groups using the χ(2) test and Fisher exact test for discrete variables and the Mann-Whitney test for continuous variables.

RESULTS

Thirty-seven children have been treated during the first era and 32 during the second one. The two groups were similar in terms of age (7.2 years vs 8.1 years; P=0.54), size of the largest stone (15 mm vs 16.2mm; P=0,56) and number of stones per patient (1.4 vs 2; P=0,07) but the sum of stone diameters was higher in group 2 (16.9 mm vs 24.2mm; P=0,048). The stone-free rates were comparable in both groups (28.1% vs 32.2% after the first procedure; P=0.72), as were the mean number of procedures per patient (2.4 vs 2.5; P=0.78), the total length of stay (2.7 days vs 2.9 days; P=0.77), and the number of patients who experienced at least one complication (37.8% vs 40.6%; P=0.87).

CONCLUSION

The acquisition of a F-URS allowed the treatment of more complex stones with a similar efficacy and without increasing morbidity. Further studies are needed to define the role of F-URS in the management of upper urinary tract stones in children.

Cost Analysis of Flexible Ureteroscope Repairs: Evaluation of 655 Procedures in a Community-Based Practice

INTRODUCTION

The frequency of flexible ureteroscopy has increased with the introduction of improved instrumentation. Ureteroscopes allow increased endoscopic access to the ureter and kidney. However, maintenance and repair of scopes may increase the total procedure expense.

METHODS

In 3 years (8/2011-7/2014), 655 flexible ureteroscopies were performed at a single-specialty, urology, ambulatory surgery center. Procedures were performed by 26 board-certified urologists using four Olympus URF P5 flexible ureteroscopes. The instruments were handled by a single team and sterilized through the STERIS System E1. Repairs were performed by the manufacturer on an as needed basis. Patient records were reviewed to determine the preoperative diagnosis, operative time, location and size of the stone, and use of laser or ureteral sheath. The occurrence, nature of flexible ureteroscope damage, and cost of repairs were evaluated.

RESULTS

Of the ureteroscopies performed, 78% was for the treatment of calculi (50.1% in the kidney). Mean stone size was 8.5 ± 0.2 mm, with larger stones (11 mm) located in the kidney. The flexible ureteroscope was advanced over a guidewire (88% of cases); a laser fiber was introduced in 70%, and a ureteral sheath was used in 13.4%. Mean procedure time was 40 minutes. The most common reasons for ureteroscope repair were cloudy lens (16 repairs) and broken optic fibers (9 repairs). There were 31 repairs during the study period (average 21 cases per repair). Flexible ureteroscopes were out of service for an average of 11 days per repair (range 3-20). The total cost of repairs was $233,150 or ∼$7521 per repair. The average repair cost per flexible ureteroscopy performed was $355.

CONCLUSIONS

Expenses associated with instrument repair can significantly impact a procedure's net revenue, thus efforts should be made to minimize instrument breakage. The expense of repairing a flexible ureteroscope per procedure can be significant and needs to be considered when pricing this procedure.