[Ureterorenoscopy with a flexible instrument].

Flexible ureterorenoscopy should be routinely used at the Urological Centers that deal with urinary stones. Flexible instruments should be used for both diagnostic and therapeutic purposes, allowing a safe exploration of the whole upper urinary tract. Thanks to their flexibility and to the active and passive deflection of their distal part, these instruments allowed to successfully treat several difficult situations, such as renal caliceal calculi in the lower calices or even in some middle/upper calices or in horseshoe kidneys. The therapeutic potential of this approach is enhanced by the large availability of ancillary instrumentation, such as baskets, grasps, holmium laser fibers, etc, which is continuously growing. On the other side, a steep learning curve of the technique is usually required for the surgeon. Furthermore, the intrinsic fragility of the instrument components and a potentially lower quality, when compared to that of the rigid and semi-rigid ureteroscopes, should be considered.