Discussion
Majdalany
The current trial is the first RCT that compares RIRS with Ho:YAG and SP TFL. Whilst it was shown that both lasers are equally safe and effective, the SP TFL (with a smaller fiber, or without) resulted in a shorter LOT and used nearly half the amount of total energy for stone ablation as Ho:YAG. The mean operation time tended to be lower in the SP TFL group compared to the Ho:YAG. However, the difference was not statistically significant.In the recently published trial by Ulvik et al. SP TFL produced better SFR than Ho:YAG (92% vs 67%) [The previous preclinical studies assumed that lithotripsy efficiency of TFL was superior to that of Ho:YAG. In an Unfortunately, our trial was conducted comparing SP TFL with a conventional Ho:YAG without pulse modulation. Majdalany et al. in their clinical study of pulse-modulated Ho:YAG in RIRS concluded that fragmentation speed (or ablation speed) was the most suitable parameter for measuring laser efficacy. In their study, pulse-modulated Ho:YAG had shown a mean fragmentation speed of 0.9 mmAs for the smaller fiber, the results of the trial are quite interesting. Whilst the use of a smaller fiber may result in additional efficacy due to its ability to create a smaller stone fragment (as suggested by Panthier et al. [Our study was also the first clinical comparison between 150-μm and 200-μm SP TFL fibers. We were able to show that there are no differences in performance parameters, except for the shorter operation time for smaller LF (60.2 ± 20.1 min and 74.4 ± 26.3 min, respectively, A 3 months, low-dose computed tomography showed that 100% of patients were stone free, with no patients showing a residual stone fragment of ≥ 3 mm which is comparable to the SFR reported in the literature [Our study is not without its limitations. The composition of stones was not presented in our trial, but the stone density assessed in all groups meant that we could evaluate laser efficacy in various types of stones. Moreover, it was shown that TFL is effective in producing stone dust from all stone types [Also, the Ho:YAG device used in the trial was a previous-generation machine without pulse modulation. We do not see this issue as a major limitation to pulse modulation for it has not proven to have superior efficacy in clinical trials. We also would like to note that the described settings (disposable instruments and LF, duration of post operation double J-stent placement, etc.) cannot be generalized to each clinical center.