Retrograde flexible ureteroscopy
Editorial Comment Editorial Comment to Retrograde ﬂexible ureteroscopic approach of upper urinary tract pathology: What is the status in 2014? Fifty years has passed since Marshall first advanced a flexible scope through an open ureterotomy into the renal pelvis in 1964.1 Recent advancements in flexible ureteroscopes (URS) have significantly improved the efficacy of the flexible URS, which broadens their applications among upper tract urolithiasis. In the current review article, Geavlete et al. have comprehensively described the recent status of flexible ureteroscope, mainly focusing on the treatment of upper urinary tract urolithiasis, and also covered its use for caliceal diverticulum, infundibular stenosis and upper urinary tract tumors.2 According to the European Association of Urology guideline 2014, URS is a useful option for the treatment of stones in the renal pelvis, upper, middle calyces and even for the lower pole. Although it is not recommended as a first-line treatment, for stones >15 mm at the renal pelvis and upper or middle calyceal, flexible URS still stands as a useful option when contraindicated for percutaneous nephrolithotomy (PCNL). For the lower pole, PCNL as well as flexible URS are recommended for stones >1.5 cm.3 Recent evidence has suggested that flexible URS might also be applicable for renal stones >20 mm.4 When looking at the type of flexible URS, a major concern of surgeons could be their visibility and manoeuvrability. As the authors described, the digital optical system, manufactured by Olympus (URF-V, URF-V2) or Karl Storz Endoskope (Flex-Xc), provides higher visibility compared with the classical fiberoptic system. In contrast, higher maneuverability can be obtained from the fiberoptic system, such as URF-P6 (Olympus), which allows a much smaller diameter (4.9/7.95-Fr for the tip/maximal) with a high deflection range (275° for both up and down) compared with that of the digital system. Although recent models of URF-V2 (Olympus) and Flex-Xc (Karl Storz Endoskope) succeeded in reducing the diameter and improving flexibility, the tips of the scopes are still 1 to 2-Fr wider compared with recent fiberoptic systems. An additional remarkable feature in flexible URS could be the development of two working channels in the Cobra (Richard Wolf). The two working channels, instead of one, ensure good irrigation even when instruments are inserted through the ureteroscope, and make it possible to simultaneously use two instruments, such as a laser fiber and an extractor. These advancements in flexible URS will possibly change the applicability as well as the procedure of the operation for upper urinary tract urolithiasis.
© 2014 The Japanese Urological Association
Although the current review article covered a wide range of topics, another interesting aspect of the flexible URS could be the simultaneous combined use with PCNL, so-called endoscopic combined intrarenal surgery. The use of a flexible endoscope during endoscopic combined intrarenal surgery contributes to minimizing radiation exposure, hemorrhagic risk and post-PCNL renal damage. Although endoscopic combined intrarenal surgery is commonly carried out in the Galdakaomodified supine Validivia position, Hamamoto et al. recently provided evidence of combining a flexible scope with minimally-invasive PCNL (mini-PCNL) carried out in the prone split-leg position, and showed a superior outcome compared with monotherapy with mini or standard PCNL.5 Significant recent advancements in terms of miniaturization of the endoscope and enhancement in optical scope will expand the application of flexible URS as a first-line minimallyinvasive stone management strategy in upper urinary tract urolithiasis. Shinichi Sakamoto M.D., Ph.D. Department of Urology, Chiba University Graduate School of Medicine, Chiba, Japan [email protected]
Conﬂict of interest None declared.
References 1 Mmarshall VF. Fiber optics in urology. J. Urol. 1964; 91: 110–14. 2 Geavlete P, Multescu R, Geavlete B. Retrograde flexible ureteroscopic approach of upper urinary tract pathology: what is the status in 2014? Int. J. Urol. 2014; 21: 1076–84. 3 Türk C, Knoll T, Petrik A et al. Guidelines on Urolithiasis. 2014. [Cited 8 Sep 2014.] Available from URL: http://www.uroweb.org/gls/pdf/22%20Urolithiasis _LR.pdf 4 Aboumarzouk OM, Monga M, Kata SG, Traxer O, Somani BK. Flexible ureteroscopy and laser lithotripsy for stones >2 cm: a systematic review and meta-analysis. J. Endourol. 2012; 26: 1257–63. 5 Hamamoto S, Yasui T, Okada A et al. Endoscopic combined intrarenal surgery for large calculi: simultaneous use of flexible ureteroscopy and mini-percutaneous nephrolithotomy overcomes the disadvantageous of percutaneous nephrolithotomy monotherapy. J. Endourol. 2014; 28: 28–33.
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