The peak power and the pulse shape represent one of the main differences between the lasers. The uniform rectangular TFL pulse shape differs from the asymmetric Ho:YAG laser pulse shape, which presents an initial energy peak followed by a rapid decline.2 Low peak power (500W) allows TFL to be an interesting option for dusting ablation lithotripsy and avoid the abrupt interaction of the Ho:YAG laser with a peak power up to 10,000W (higher retropulsion).3
As described in the literature, a peculiarity of Ho:YAG is the pulse spike shape, as well as its high peak powers, which are responsible for an “explosive” effect with a rise in temperature and instantaneous vaporization of the water.4 The stone fragmentation mechanism is predominantly photothermal, causing the chemical decomposition of urinary calculi through direct energy absorption, with minimal contribution from significant photomechanical or photoacoustic effects.5 At the same time, the high peak power for the short and medium pulse durations could be linked to a burn-back effect of the optical fibers, with consequent increment of the operative time.
Recent advancements in Ho:YAG lasers, including increased power and pulse frequency, have enabled sophisticated "dusting" techniques that pulverize stones into fine particles for spontaneous passage.6 Furthermore, specialized pulse modulations, such as MOSES™ technology, Vapor Tunnel TM, Virtual BasketTM, have been introduced. These innovations aim to improve energy transmission through the surrounding fluid medium and mitigate stone retropulsion by asymmetrically modifying the laser pulse profile, yet employ distinct methods.
More recently, the development of the TFL has marked a significant turning point.7 Conceptually distinct from Ho:YAG, TFL utilizes a thulium-doped optical fiber as its active medium and diode pumps instead of flash lamps.8 This design offers numerous advantages, including greater versatility and a wide range of energy, frequency, and pulse duration settings. Notably, TFL distinguishes itself with superior ablation efficiency, the ability to produce finer dust ("dusting"), and a significant reduction in stone retropulsion. This is primarily because its wavelength (1940 nm) is absorbed by water approximately four times more effectively than Ho:YAG (2100 nm), and it operates with a lower peak power.
In this landscape of continuous pursuit for safer and more efficient technologies, Magneto Ho:YAG (M-Ho:YAG) technology has been introduced. This represents a new pulse modulation specifically integrated into high-power Ho:YAG laser generators. The primary goal of Magneto is to enhance lithotripsy performance, particularly in dusting efficacy and reduction of stone retropulsion. This is achieved by extending the duration of emitted pulses up to 2000 µs and significantly reducing the holmium peak power to 500 W .10 This makes its conceptual approach very similar to TFL, which also operates with constant low peak power. Although clinical and laboratory data on this specific technology are still limited, initial experiences suggest good ablative efficacy, a satisfactory anti-retropulsion effect, and a favorable safety profile for the endoscopic treatment of renal and ureteral stones. Figure 1 shows the main differences between the different lasers, highlighting the similarity between both lasers evaluated in the present study.
Figure 1. Peak Power for Ho:YAG - M-Ho:YAG and TFL
The ‘suction’ is not new in the endourology world, but recently the suction scopes and suction ureteral access sheaths have emerged as an interesting option with improvements in total operative time and stone-free rate (SFR).11 Flexible and navigable suction ureteral access sheath (FANS) consists of a ureteral access sheath with a distal flexible segment and a connection system to an external aspiration that allows for an active suction of the dust debris and the stone fragments while following the movements of the flexible ureteroscope in the renal cavities.
Given TFL's established role as an advanced laser for lithotripsy and the introduction of M-Ho:YAG technology—which shares the goal of improving dusting with reduced retropulsion—it is fundamentally important to directly compare the intraoperative performance of these two innovative technologies. Therefore, the purpose of this study is to compare the intraoperative outcomes between the TFL and M-Ho:YAG laser for lithotripsy during flexible ureteroscopy in patients with non-complex kidney stones.
We performed a retrospective analysis of RIRS with FANS for non-complex kidney stones in which we used TFL (Fiber Dust®, Quanta System, Sama¬rate, Italy) and M-Ho:YAG laser (CyberHo Magneto®, Quanta System, Sama¬rate, Italy). We included 127 patients and divided them into Group 1 = M-Ho:YAG and Group 2 = TFL. Table 1 shows the demographic variables.
Table 1. Demographic characteristics
|
All (n=127) |
Magneto (n=51) |
TFL (n=76) |
P value |
|
|
Age years, median (IQR) |
58 (42-65) |
58 (44-64) |
59 (41-65) |
0,79 |
|
Female, n (%) |
43 (33.9) |
18 (35.2) |
31 (40.8) |
0,51 |
|
BMI kg/m2, median (IQR) |
26 (24-31.7) |
26 (24.4-31.7) |
27 (24-30.6) |
0,16 |
|
Right side, n (%) |
55 (43.3) |
23 (45.1) |
32 (42.1) |
0,49 |
|
Stone Volume (mm3), median (IQR) |
772 (590-1050) |
751 (560-1050) |
797 (631-977) |
0,75 |
|
Stone Density (HU), median (IQR) |
922 (521-1100) |
976 (474-1100) |
915 (563-1023) |
0,78 |
|
Prestenting, n (%) |
51 (40.2) |
21 (41.2) |
30 (39.5) |
0,85 |
* Statistically significant
Table 2 shows the intraoperative and postoperative results. Both groups presented comparable median total laser energy. Median total operative time (47.5min vs. 44min, p=0.67) and median total laser time (12.8min vs. 13.7min, p=0.17) were comparable between both groups. In addition, there was no significant difference between the main important intraoperative parameters: laser energy consumption (Joules/mm3), ablation efficiency (mm3/Joules), and ablation efficacy (mm3/min) 25.7. In addition, SFR was comparable between both groups (98% vs. 94.7%, p=0.35), and there was no difference between both groups in Clavien-Dindo grade≤2 (3.9% vs.3.9%, p=0.99), and no patients presented major complications.
Table 2. Intraoperative and Postoperative Results.
|
All (n=127) |
Magneto (n=51) |
TFL (n=76) |
P value |
|
|
Total energy (kJ), median (IQR) |
10.1 (8.1-12.8) |
9.9 (8.1-11.6) |
10.6 (8.6-12.8) |
0.33 |
|
Laser time (min), median (IQR) |
14.4 (11.2-17.2) |
12.8 (11.2-17.2) |
13.7 (12.4-16.9) |
0.17 |
|
Total operative time (min), median (IQR) |
45 (35-58) |
47.5 (38-54) |
44 (35-58) |
0.67 |
|
Postoperative stent, n (%) |
92 (72.44) |
39 (76.4) |
53 (69.7) |
0.41 |
|
Stone-free rate (SFR), n(%) |
122 (96.1) |
50 (98.0) |
72 (94.7) |
0.35 |
|
Complications by Clavien–Dindo grade≤2, n (%) |
5 (3.9) |
2 (3.9) |
3 (3.9) |
0.99 |
|
JJ/mm3, median (IQR) |
10.9 (9.8-11.8) |
11.5 (10.4-11.8) |
11.1 (9.8-11.3) |
0.68 |
|
mm3/JJ, median (IQR) |
0.15 (0.09-0.28) |
0.18 (0.12-0.28) |
0.16 (0.09-0.18) |
0.76 |
|
mm3/min, median (IQR) |
23.5 (18.8-26.4) |
25.7 (24.5-26.4) |
24.7 (18.8-24.9) |
0.49 |
JJ = Joules
* statistical significatively
We performed the first clinical comparison between M-Ho:YAG and TFL, and no significant differences were found in the most relevant intraoperative and postoperative results. Larger and randomized studies are required to confirm these initial outcomes.
Written by: Luis Rico, Department of Urology, Hospital Alemán, Buenos Aires, Argentina.
References:
- Traxer O, Keller EX. Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser. World J Urol. 2020 Aug;38(8):1883-1894. doi: 10.1007/s00345-019-02654-5. Epub 2019 Feb 6
- Soto-Palou F, Chen J, Medairos R, Zhong P, Antonelli J, Preminger GM, Lipkin ME. In Pursuit of the Optimal Dusting Settings with the Thulium Fiber Laser: An In Vitro Assessment. J Endourol. 2023 Aug;37(8):914-920. doi: 10.1089/end.2023.0168. Epub 2023 Jun 26
- Kartalas Goumas I, Panthier F, De Coninck V, Salonia A, Traxer O, Ventimiglia E. Thulium Fiber Laser and the Quest for Optimal Laser Parameters: May Peak Power Be the Answer? J Endourol. 2024 May;38(5):531-532. doi: 10.1089/end.2023.0409. Epub 2024 Apr 1
- Doizi S, Germain T, Panthier F, et al. Comparison of Holmium:YAG and Thulium Fiber Lasers on Soft Tissue: An Ex Vivo Study. J Endourol 2022;36(2):251–258; doi: 10.1089/end.2021.0263.
- Kudo D, Anan G, Okuyama Y, et al. Initial experience of thulium fiber laser in retrograde intrarenal surgery for ureteral and renal stones in Japan: surgical outcomes and safety assessment compared with holmium: yttrium-aluminum-garnet with MOSES technology. BMC Urol 2025;25(1):71; doi: 10.1186/s12894-025-01738-2.
- Higgins AM, Wolf MJ, Becker REN, et al. How I Do It: Ureteroscopy and high-power holmium laser lithotripsy to treat renal stones. Can J Urol 2023;30(3):11574–11582.
- Terry RS, Whelan PS, Lipkin ME. New devices for kidney stone management. Curr Opin Urol. 2020 Mar;30(2):144-148. doi: 10.1097/MOU.0000000000000710
- Fried NM, Irby PB. Advances in laser technology and fibre-optic delivery systems in lithotripsy. Nat Rev Urol. 2018 Sep;15(9):563-573. doi: 10.1038/s41585-018-0035-8
- Sierra A, Corrales M, Somani B, et al. Laser Efficiency and Laser Safety: Holmium YAG vs. Thulium Fiber Laser. J Clin Med 2022;12(1):149; doi: 10.3390/jcm12010149.
- Perri D, Besana U, Mazzoleni F, Maltagliati M, Pacchetti A, Calcagnile T, Bozzini G. Cyber Ho generator with Magneto technology: the first experience of a new concept of hybrid HoLEP. Minerva Urol Nephrol. 2025 Apr;77(2):277-279. doi: 10.23736/S2724-6051.25.06384-0. Epub 2025 Mar 17.
- Rico L, Diaz-Zorita V, Blas L, Ramos LB, Sabeh P, Contreras P. Is the ablation stone efficacy and efficiency better with a flexible and navigable suction ureteric access sheath? World J Urol. 2025 Apr 9;43(1):219. doi: 10.1007/s00345-025-05610-8