Single-use digital flexible ureterorenoscopes are emerging as an alternative to the well-known reusable scopes. Flexible ureterorenoscopy (fURS) is a procedure that requires a multitude of conditions to achieve the best results, the most obvious of these being proper visualisation. Besides the ureterorenoscope’s optical characteristics, good irrigation is vital for enhanced visibility of the area under examination. Performing this study, the goal was to discover if the emerging single-use scopes provide similar, or hopefully even better, irrigation compared to their reusable counterparts.
In this study, four single-use (LithoVue, Boston Scientific, Marlborough, Massachusetts, USA; Pusen, Zhuhai Pusen Medical Technology Company Ltd., Zhuhai, China; NeoFlex, Neoscope, Silicon Valley, California, USA; YouCare, YouCare Technology Co., Ltd., Wuhan, China) and four reusable (URF-V2, Olympus, Tokyo, Japan; Flex Xc, Karl Storz, Tuttlingen, Germany; BOA vision and COBRA vision, Richard Wolf GmbH, Knittlingen, Germany) digital flexible scopes were used. The irrigation flow was measured with saline at heights of 40 cm and 80 cm through the fURS empty channel and with various tools inserted in the working channel at deflection angles of 0° and maximal.
The YouCare scope had the highest flow, which was to be expected due to the 4.2 Fr working channel. The working channel of all other scopes used is 3.6 Fr, except COBRA vision, which has two channels (3.6 Fr and 2.4 Fr). The irrigation flow decreased for all fURS as the size of the working tools in the channel increased. On all scopes the smaller 220 µm laser fibre had the lowest impact on the irrigation flow, and the Piranha biopsy forceps (Boston Scientific) had the highest impact. Although the flow of COBRA vision was affected when working tools were inserted via the 3.6 Fr channel, it was not impaired when they were inserted through the 2.4 Fr channel.
Maximal deflection had a very slight impact on the irrigation flow, which was similar for both single-use and reusable scopes, although this was not statistically significant. Collectively, all single-use scopes had better flow compared to the reusable scopes when the working channel was occupied, although again this was not statistically significant. To conclude, our study affirms that single-use flexible scopes have a slightly better irrigation flow in vitro than their reusable counterparts for empty or occupied working channels, irrespective of the scope’s deflection. Further in vivo trials are needed to confirm these findings in clinical situations.
COMMENTS FROM THE EUROPEAN ASSOCIATION OF UROLOGY (EAU) CONGRESS 2018 PRESENTATION
Presenting our work at the European Association of Urology (EAU) Congress 2018, we were happy to find that many of our colleagues shared our opinion that the use of single-use flexible scopes may be a great step forward in the treatment of kidney or upper ureteric stones, allowing a less invasive and successful treatment option for a larger number of patients. It may be the case that in the near future, single-use tools will fully replace the reusable counterparts. We assume that single-use scopes have the advantage of lowering nosocomial urinary tract infection rates and do not require any supplementary sterilisation and maintenance costs. Although at present the price of single-use scopes seems to be a disadvantage for some countries, there are studies that have showed that for lower volume centres (<60 cases per year), the current single-use scopes were more cost-effective than the reusable alternatives.
Discussions were mainly focussed on the quality of single-use scopes utilised in this study and the necessity of confirming the in vitro findings through proper in vivo evaluations. Still, this study showed that, at least considering the irrigation flow, single-use scopes reach the same, or even better, performance levels than the reusable scopes, and the presented results were appreciated during the EAU 2018 congress. As a result and broader implication of our conclusions, urologists all over the world might consider single-use scopes as the paradigm-changing tools of the future that will greatly influence the way we are going to actively treat urolithiasis.