Effect of optical fiber diameter and laser emission mode (cw vs pulse) on tissue damage profile using 1.94 µm Tm:fiber lasers in a porcine kidney model



To evaluate the ablation capacity using two Thulium fiber lasers (TFL) in a porcine kidney model.


All tissue samples were mounted on a motorized stage for a precise speed of cutting. A continuous wave (cw) TFL and a super pulsed (SP) TFL were used at power settings of 60 and 120 W with 200 and 600 µm laser fibers. After lactate dehydrogenase staining, histological evaluation was performed to measure the vaporization volume (VV), ablation depth (AD), thermo-mechanical damage zones (TMZ), coagulation zones (CZ) and the carbonization grade (CG).


At 120 W, no significant differences were seen between 200 and 600 µm fibers utilizing the cw TFL regarding VV (24.6 vs. 28.2 mm3/s), AD (5.6 vs. 5.7 mm), TMZ (0 vs. 0 mm2) and CZ (18.1 vs. 12.3 mm2). Using the SP TFL, no significant differences between both fiber diameters with regard to VV (4 vs. 6.2 mm3/s), AD (2.7 vs. 3.4 mm), TMZ (1 vs. 2.6 mm2) and CZ (3.1 vs. 2.2 mm2) at 120 W were found, respectively. However, the VV of the cw TFL at 60 W was significantly less compared to 120 W using 200 and 600 µm fibers, respectively, whereas the SP TFL did not show significant differences between 60 and 120 W with regard to VV. SP TFL showed a consistently lower CG compared to cw TFL.


This experiment suggests that there is no significant difference using 200 or 600 µm laser fibers in cw or SP TFLs. However, the cw TFL produces a coagulation zone three to five times larger than the SP TFL regardless of the fiber diameter.

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All authors whose names appear on the submission have contributed sufficiently to the scientific work and therefore share collective responsibility and accountability for the results. BB: project development, data collection, data analysis, manuscript writing/editing. DE: project development, data collection, data analysis, manuscript editing. PG: project development, manuscript editing. LR: project development, manuscript editing. MT: project development, data collection, data analysis, manuscript editing. AJG: project development, manuscript editing. VV: project development, data collection, data analysis. TRWH: project development, manuscript editing. CN: project development, data collection, data analysis, manuscript editing.

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Correspondence to Benedikt Becker.

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Becker, B., Enikeev, D., Glybochko, P. et al. Effect of optical fiber diameter and laser emission mode (cw vs pulse) on tissue damage profile using 1.94 µm Tm:fiber lasers in a porcine kidney model. World J Urol 38, 1563–1568 (2020). https://doi.org/10.1007/s00345-019-02944-y

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  • In-vitro
  • Thulium fiber laser
  • Porcine kidney
  • Laser