Temperature changes during laser lithotripsy with Ho:YAG laser and novel Tm-fiber laser: a comparative in-vitro study.

AIM: The aim of this study was to compare the thermal effects of Ho:YAG and Tm-fiber lasers during lithotripsy in an in-vitro model via real-time temperature measurement. METHODS: We compared a Ho:YAG laser (pav up to 100 W, Lumenis, Yokneam, Israel) and a superpulse Tm-fiber laser (SP TFL, pav up to 40 W, NTO IRE-Polus, Fryazino, Russia), both equipped with 200 µm bare-ended fibers. The following settings were used: 0.2 J, 40 Hz (nominal pav 8 W). Power meter FieldMaxII-TO (Coherent, Santa Clara, CA, USA) was used to verify output laser power (pav). Each laser was fired for 60 s in two setups: (1) thermos-insulated (quasi-adiabatic) cuvette; (2) actively irrigated setup with precise flow control (irrigation rates 0, 10, 35 mL/min). RESULTS: Power measurements performed before the test revealed a 10% power drop in Ho:YAG (up to 7.2 ± 0.1 W) and 6.25% power drop in SP TFL (up to 7.5 ± 0.1). At the second step of our experiment, irrigation reduced the respective temperatures in the same manner for both lasers (e.g., at 35 mL/s SP TFL - 1.9 °C; for Ho:YAG laser - 2.8 °C at 60 s). CONCLUSION: SP TFL and Ho:YAG lasers are not different in terms of volume-averaged temperature increase when the same settings are used in both lasers. Local temperature rises may fluctuate to some degree and differ for the two lasers due to varying jet streaming caused by non-uniform heating of the aqueous medium by laser light.

Extracorporeal ureter handling during laparoscopic pyeloplasty: tips and tricks for beginners.

INTRODUCTION: Laparoscopic preparation of the ureter is a challenging part of upper urinary tract reconstruction, due to limited depth perception provided by the camera and lack of wristed motion of most laparoscopic instruments needed for adequate spatulation and scar tissue removal. One solution has been to perform the more difficult portions of the surgery in an extracorporeal manner. A hybrid intracorporeal-extracorporeal approach to upper tract ureteral reconstruction facilitates ureteral preparation at the stage of mastering the technique. MATERIAL AND METHODS: This retrospective study included 100 patients with primary ureteropelvic junction obstruction, who underwent laparoscopic pyeloplasty from 2014 to 2017. The patients were stratified into 2 groups: those who underwent conventional laparoscopic surgery and those who were managed with the hybrid approach. For the hybrid approach, externalizing the ureter to skin level required additional mobilization of the upper urinary tract. RESULTS: A total of 47 patients underwent conventional laparoscopic pyeloplasty and 53 - hybrid surgery. The maximum body mass index was 32. The hybrid approach was 8.5 minutes shorter compared to the conventional approach (p <0.001). No complications higher than Clavien-Dindo IIIb (n = 2) were observed (in both groups). Complete success (the resolution of pain and/or hydronephrosis) was observed in 92.5% in the hybrid group and in 95.7% in the conventional treatment group. CONCLUSIONS: Hybrid pyeloplasty may be considered safe and effective. It has the advantage of making the surgery less challenging and time-consuming while offering improved precision. The advantages of the technique are particularly apparent during training. This technique can be recommended in the learning process of the surgeon.