Role of ‘dusting and pop-dusting’ using a high-powered (100 W) laser machine in the treatment of large stones (≥ 15 mm): prospective outcomes over 16 months

Abstract

Ureteroscopy and laser stone fragmentation (URSL) has had recent advancements with the more powerful laser systems with the ability to 'dust' and 'pop-dust' the stone. We wanted to look at the outcomes of this method for large stones (≥ 15 mm) using our new 100 W holmium laser. Over a period of 16 months (January 2017-April 2018), 50 patients underwent URSL for minimum cumulative stone size of ≥ 15 mm. Data were collected prospectively on patient and stone demographics and outcomes of URSL. The laser setting used was a power of 0.3-0.6 J and a frequency of 20-50 Hz using a long-pulse setting with a 272-µm fiber. Fifty patients underwent 55 URSL procedures (5 bilateral procedures) using dusting and pop-dusting settings. The mean age was 58 years (range 2-88 years) with a male:female ratio of 35:15. The mean single and overall stone size were 10.3 mm (3-23 mm) and 21 mm (range 15-52 mm) with two-thirds of all patients (65%) having multiple stones. The stone location was in the kidney (n = 65, 78%), in the ureter (n = 19, 22%) and 5 patients had bilateral renal stones. With a mean operating time of 51 min, the initial and final SFR were 93 and 98%, respectively. A pre-operative stent, access sheath and a post-operative stent were present in 29 (53%), 34 (62%) and 51 (93%) procedures, respectively. Over a mean hospital stay of 0.6 days (74% day-case procedures), there was one Clavien IV complication related to urosepsis but without any other major or minor complications. Dusting and pop-dusting techniques achieve an excellent SFR with low risk of complications even for large stones. This might set a new benchmark for treating large stones, bilateral or multiple stones in a single setting, without the need for secondary procedures in most cases.

Thermal effect of holmium laser during ureteroscopic lithotripsy

“…Second, apply "high-frequency" setting with more caution. Previous study have showed that dusting maneuver with higher frequency can acquire better stone free rates for renal calculi [15]. Even though the dusting maneuver is more timeconsuming and will produce more heat, the renal pelvis can disperse the heat quickly because of its larger space comparing with ureter.…”

Patterns of Laser Activation During Ureteroscopic Lithotripsy: Effects on Caliceal Fluid Temperature and Thermal Dose

“…Fortunately, from the analysis of clinical cases, the mean length of pedal activation was found to be relatively short-3.6 seconds. Although high-power laser techniques have clinical advantages, 12,13 urologist need to be mindful of ODC and keep pedal activation times as short as possible.…”

Worldwide survey of flexible ureteroscopy practice: a survey from European Association of Urology sections of young academic urologists and uro-technology groups

“…The introduction of modern high-power lasers with newer lasertripsy methods has allowed treating large renal stones in complex patients with a reduced operating time [8]. The safety in high-risk patient groups is now well established and the use use of peri-operative antibiotics, access sheath usage, method of stone treatment and the use of postoperative stent.…”