Surgery Illustrated - Focus on Details Flexible ureterorenoscopy (URS) for lower pole calculi

Occasionally, despite the measures described above, lower pole access may be unsuccessful [3]. Dual active deflection or 270° active deflection ureterorenoscopes can be helpful in such cases [4]. Sometimes the neck of the calyx is too tight or the stone may not be lying in the collecting system. Flexible URS can differentiate between a small calyceal stone and renal parenchymal calcification. When primary in situ laser fragmentation is used, it may be difficult to get'on top of the stone' even after maximum rotation of the ureterorenoscope. In such circumstances, one has to be careful the laser is not activated whilst the fibre is alongside the stone, as this can traumatise the infundibular wall and even lead to infundibular stenosis. In such cases, the basket should be used early on to displace the stone. Advantages of the nitinol basket displacement technique include using a larger laser fibre for greater energy delivery and fragmentation, as well as leaving small fragments in less dependent calyces for better post-procedural drainage [5]. In one study, the stone-free rate improved from 71% for stones treated in situ to 94% for displaced stones [6]. Recent studies have shown that the success rate for lower pole stones of <2 cm treated with flexible URS are better than that achieved with ESWL [1]. Success rates for flexible URS of lower pole stones using the holmium laser have been as high as 91% in one recent study [7]. In our institution, an audit of 137 consecutive lower pole stones treated with flexible URS showed an overall success rate of 82%, with 90% for stones of <1 cm [8]. However, success rates for stones of >2 cm were considerably lower (50%). PCNL remains the first-line treatment for stones of >2 cm, although flexible URS is still a reasonable option in high-risk patients, such as those on anticoagulation therapy and the morbidly obese [9]. © 2012 The Authors BJU International © 2012 BJU International.