Critical Assessment of Single-Use Ureteroscopes in an In Vivo Porcine Model

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.

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.

Device Failure and Adverse Events Related to Single-use and Reusable Flexible Ureteroscopes: Findings and New Insights From an 11-Year Analysis of the Manufacturer and User Facility Device Experience Database

OBJECTIVE

To catalog and characterize device failures and adverse events related to flexible ureteroscopes from a national database.

METHODS

Search of the Manufacturer User and Facility Device Experience database was performed for all recorded events related to flexible ureteroscopes between 2012 and 2022. The following information was collected: Problem and cause, timing, complications and injury, prolonged anesthesia, and early termination of procedure. Event severity was graded using a validated tool.

RESULTS

A total of 206 events were identified (reusable/single use ratio, 2.5:1). There were 20 different problem categories reported, which included image loss (26.7%), difficulty removing scope (13.6%), scope damage from basket (4.4%), detachment of scope tip (5.8%) and contamination (4.9%). Faulty device was the predominant cause for an event related to single-use scopes (86.4%); this was seldom the case for reusable (2%). Patient injury occurred in 21.8%, but these were all in reusable scopes. No deaths were reported, but major complications included complete avulsion of the ureter (3.4%) and fully entrapped scope necessitating open surgery (2.9%). While the safety profile for single-use scopes was superior, they were significantly more likely to result in early termination (71.1% vs 37.3%, P < .001). This was related to 76.3% of the single-use scopes experiencing sudden image loss.

CONCLUSION

Flexible ureteroscopes are fragile, and a multitude of problems can occur. Many of these can be avoided through correct surgeon technique and robust maintenance services.

Determining the threshold of acute renal parenchymal damage for intrarenal pressure during flexible ureteroscopy using an in vivo pig model

PURPOSE

To identify a threshold for intrarenal pressure (IRP), that if exceeded, will result in renal parenchymal damage. Herein, we attempt to identify an IRP threshold by subjecting in vivo porcine kidneys to various levels of extreme pressurized irrigation. Our objective was not to simulate ureteroscopy treatment, but to attempt identify a threshold of IRP injury.

METHODS

Ten female pigs were intubated and sedated. The abdomen was opened; the ureters were isolated and incised. A LithoVue™ (Boston Scientific) ureteroscope was inserted. A 0-silk tie was then used to tie the ureter around the scope to create a closed system (to achieve a constant level of pressure). Real-time IRPs were measured using the Comet™ Pressure guidewire (Boston Scientific). Kidneys were exposed to pressurized, saline for 36 min (at control, 50, 100, 150 mmHg and higher pressures). Kidneys were then immediately harvested. Two expert histologists independently analyzed kidney slides to identify areas of renal damage.

RESULTS

The two kidneys exposed to IRPs > 185 mmHg resulted in forniceal rupture and large areas of hematoma. The other IRP groups (control, 50, 100, and 150 mmHg) had no identifiable gross or histologic renal parenchymal damage.

CONCLUSIONS

No differences in renal parenchymal morphology were identified between pressure groups of control, 50, 100, or 150 mmHg. However, IRPs > 185 mmHg did result in forniceal rupture in this closed-system in vivo porcine model. Further study is required to elucidate the damage threshold.

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.