Pulsed Thulium:YAG (Tm:YAG) laser recently gained prominence as a novel tool within the endourologist’s armamentarium. There is however little real-world data on its performance for laser lithotripsy in retrograde intrarenal surgery (RIRS), when compared with more established lasers such as Holmium:YAG and Thulium fibre laser. We aim evaluate the efficiency, safety and outcome of using Tm:YAG laser during RIRS within our institute.

All patients who have undergone RIRS for laser lithotripsy with Tm:YAG laser (RevoLix™ HTL, LISA Laser, Katlenburg-Lindau, Germany) in our institute’s day-case unit from September 2022 till April 2024 were identified. Their data including age, stone size, duration of operation, size of laser fibre, total energy use, presence of ureteric injury, complication such as stricture as well as stone free rate were retrospectively identified and analysed.

A total of 154 patients was identified to fit the study criteria; 25 patients were excluded as they were lost to follow-up. 43.4% of the included patients had renal stone(s), 42.6% of them had ureteric stone(s) and 14% of them had stones in both regions. 44.2% the stones are on right side, 55% of the stones are on the left and only 0.8% of them were bilateral. The median age of patient was 36 and the median stone size was 9mm (IQR 6-12mm). The median total duration of laser use was 321 seconds, and the median total energy used was 3346J. The day-case rate was 98%. Intraoperatively, 14 patients (11%) had ureteric injury, with majority (11 patients) sustaining only post-ureteroscopic lesion scale (PULS) grade 1 injury. Amongst them, it was thought that 6 patients (4.7%) had injury secondary to laser use. Within 30-days post-op, 2 patients (1.6%) were reported to have Clavien-Dindo grade 3 complications. With a median follow-up time of 6 months (IQR 3- 8 months), the stone free rate (defined as residual of < 4mm) was 72%; four patients (3.1%) developed ureteric stricture.

This is the largest single-centre real-world series for RIRS with pulsed Tm:YAG laser in the United Kingdom to date. It demonstrates a similar efficacy and safety profile when compared with other more established lasers in RIRS laser lithotripsy. Further robust direct comparative trials with other laser modalities will be useful.