Purpose: To compare the operating modes of the Holmium:YAG laser and Thulium fiber laser. Additionally, currently available literature on Thulium fiber laser lithotripsy is reviewed. Materials and methods: Medline, Scopus, Embase, and Web of Science databases were searched for articles relating to the operating modes of Holmium:YAG and Thulium fiber lasers, including systematic review of articles on Thulium fiber laser lithotripsy. Results: The laser beam emerging from the Holmium:YAG laser involves fundamental architectural design constraints compared to the Thulium fiber laser. These differences translate into multiple potential advantages in favor of the Thulium fiber laser: four-fold higher absorption coefficient in water, smaller operating laser fibers (50–150 µm core diameter), lower energy per pulse (as low as 0.025 J), and higher maximal pulse repetition rate (up to 2000 Hz). Multiple comparative in vitro studies suggest a 1.5–4 times faster stone ablation rate in favor of the Thulium fiber laser. Conclusions: The Thulium fiber laser overcomes the main limitations reported with the Holmium:YAG laser relating to lithotripsy, based on preliminary in vitro studies. This innovative laser technology seems particularly advantageous for ureteroscopy and may become an important milestone for kidney stone treatment.

Ureteral access sheaths (UASs) are part of urologist’s armamentarium when performing retrograde intrarenal surgery (RIRS). Recently, the world of RIRS has changed dramatically with the development of three game-changers: thulium fiber laser (TFL), smaller size single use digital flexible ureterosopes and intraoperative intrarenal pressure (IRP) measurement devices. We aimed to clarify the impact of UASs on IRP, complications and SFRs and put its indications in perspective of these three major technological improvements. A systematic review of the literature using the Medline, Scopus and Web of Science databases was performed by two authors and relevant studies were selected according to PRISMA guidelines. Recent studies showed that using a UAS lowers IRP and intrarenal temperature by increasing irrigation outflow during RIRS. Data on the impact of a UAS on SFRs, postoperative pain, risk of infectious complications, risk of ureteral strictures and risk of bladder recurrence of urothelial carcinoma after diagnostic RIRS were inconclusive. Prestenting for at least one week resulted in ureteral enlargement, while the influence of pre-operative administration of alpha-blockers was unclear. Since TFL, smaller single use digital ureteroscopes and devices with integrated pressure-measuring and aspiration technology seemed to increase SFRs and decrease pressure and temperature related complications, indications on the use of a UAS may decrease in the near future.