Figure 2 The principles of treating stones ureteroscopically Figure 2 | The principles of treating stones ureteroscopically. a | Stone dust can be created by systematically treating the stone with the activated holmium laser fibre (a process known as 'painting') thereby creating small particles and dust (<1-2 mm in size) to theoretically enable spontaneous passage of the small particles. b | The stone can be fragmented into pieces typically 1–4 mm in size, depending on the inner lumen of ureteral access sheath used, which can be safely extracted with a basket or grasper in an efficient manner. c | The 'popcorn' technique — which is considered to be a component of the dusting technique — in which the energy of the laser and continuous irrigation flow enables the creation of small stone particles and dust from the remaining stone fragments. Weiss, B. & Shah, O. (2016) Evaluation of dusting versus basketing — can new technologies improve stone-free rates? Nat. Rev. Urol. doi:10.1038/nrurol.2016.172