Initial clinical experience with the new thulium fiber laser: first 50 cases

To evaluate the efficacy, safety, and laser settings of thulium fiber laser (TFL) in laser lithotripsy during retrograde intrarenal surgery (RIRS) for ureteral and renal stones. A prospective study of the first 50 patients with ureteral and renal stones who underwent RIRS using TFL (SOLTIVE Premium, Olympus, Japan) was performed. 200 and 150 µm laser fibers were used for ureteral and renal stones, respectively. Stone size, stone density, laser-on time (LOT), and laser settings were recorded. We also assessed the ablation speed (mm3/s), laser power (W), and Joules/mm3 values for each lithotripsy. A total of 50 patients were included in the study with a median (IQR) age of 66 (55.5–74) years old for patients with ureteral stones and 55 (44–61.5) years old for patients with renal stones. Most of the patients had a Charlson comorbidity index score of 0. Median (IQR) stone volume for ureteral stones was 486 (332–1250) mm3 and for renal stones was 1800 (682.8–2760) mm3. Median (IQR) stone density for ureteral and renal stones was 998 (776–1300) HU and 1200 (750–1300) HU, respectively. Median (IQR) pulse energy for ureteral stones was 0.4 (0.2–0.4) J; and for renal stones, 0.3 (0.2–0.6) J. Median pulse frequency, laser power, and laser operative time were higher in the renal stones group. The overall complication rate was low in both groups. TFL is a safe and effective modality for lithotripsy during RIRS with minimal complication rates.