V01-02: Comprehensive clinical study of Super Pulse Tm fiber laser for treatment of stone disease
Recently, SuperPulse Thulium (Tm) fiber laser (NPO IRE-Polus) with wavelength of 1.94 µm was introduced as a promising lithotripsy tool. In preclinical study, we have found its efficacy to be higher than the leading Ho:YAG laser for fragmentation (x1.7 times) and dusting (x2.3 to 4 times) for equal energy and repetition rate settings. In this work, we report results of the on-going clinical study aimed at comprehensive evaluation of safety and efficacy of the new laser.
The SuperPulse Tm fiber laser device has been cleared for clinical use by the Ministry of Health of Russian Federation and the protocol has been approved by the institutional Ethical Review committee. We prospectively analyzed 268 patients (173 – kidney, 80 – ureteral, 15 – bladder stones) who underwent SuperPulse Tm fiber laser lithotripsy. Stone size, its density, operative and “laser on” time (LOT) were measured. Based on surgeon’s feedback, retropulsion and intraoperative visibility were assessed.
For kidney stones, the average size was 11.4 mm (7 – 25 mm), for ureteral stones – 7.6 mm (3 – 18 mm), for bladder stones – 22.2 mm (9 – 36 mm). The average stone density for kidney stones was 987 HU (330 – 1960 HU), for ureteral stones - 995 HU (460 – 1700 HU), for bladder stones – 980 HU (860 – 1050 HU). The average time to complete renal stone fragmentation (to dust or small fragments) was 27.2 min, for ureteral stones – 17.1 min, for bladder stones – 19 min. LOT was 24.3; 12.7 and 14.5 min for kidney, ureter and bladder stones, respectively. The retropulsion was insignificant in all cases with energy level less than 0.5 J. Visibility was estimated as optimal by surgeons in most cases. Fragmentation mode with energy level 2 to 5J and repetition rate 5-10 Hz was most suitable for bladder stone disintegration. Overall, the settings of 0.1-0.2J/15-30W; 0.2-0.5J/10-15W and 2-5J/30-50W were identified as optimal for kidney (dusting), ureter (dusting and fragmentation), and bladder (fragmentation) stones, respectively. No urinary tract injuries and optic or working channel damages were observed. There were no complications graded higher then IIIa according to Clavien-Dindo classification in this cohort.
Based on the analysis of data on 268 subjects available today, the SuperPulse Tm fiber laser is safe and efficacious for all types of urinary stones in all relevant anatomic locations.