Basic Science: BPH/LUTS
Moderated Poster Session
MP3-1 - Tissue effects of different laser fibre diameters using 1.94 µm Tm:fibre lasers in a pig kidney model
Thursday, September 20
4:00 PM - 6:00 PM
Location: Room 243
Presenting Author(s)
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Author(s)
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Dmitry Enikeev, MD, PhD
Deputy Director for Science
Institute for Urology and Reproductive health, Sechenov University
PG
LR
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Andreas J. Gross
Head of Department
Asklepios Klinik Barmbek, Abteilung für Urologie
Introduction & Objective : Aim of this study was to evaluate the ablation capacity and coagulation depth of different laser fibre diameters using a high peak power pulsed Thulium (Tm):fibre laser and a continuous wave (cw) Tm:fibre laser in a pig kidney model.
Methods : All soft tissue samples were obtained from a pig kidney and mounted on a motorized translation XY stage to ensure a precise speed of cutting (2 mm/s). A cw Tm:fibre laser (120-W peak power) and a prototype high peak power pulsed Tm:fibre laser (1000-W peak power) both emitting at 1.94 µm were used at the same average power of 60-W and 120-W, respectively. Energy was delivered using a 200 µm and a 600 µm bare-ended fibre. After Lactat Dehydrogenase (LDH)-staining of the embedded specimens, histological evaluation was performed to compare vaporization volume, ablation depth, thermo-mechanical damage zone, coagulation zone and the depth of necrotic tissue layer between both Tm:fibre lasers and fibre diameters, respectively.
Results : Using the cw Tm:fibre laser at 120-W (cutting speed 2 mm/s), no significant differences were seen between both fibre diameters with regard to vaporization volume (24.6 vs. 28.2 mm3/s), ablation depth (5.7 vs. 5.6 mm), thermo-mechanical damage zone (0 vs. 0 mm2) and the coagulation zone (18.1 vs. 11.3 mm2). Regarding the high peak power pulsed Tm:fibre laser, no differences were found between both fibre diameters with regard to vaporization volume (4 vs. 3 mm3/s), ablation depth (2.7 vs. 2.5 mm), thermo-mechanical damage zone (1 vs. 1.3 mm2) and the coagulation zone (3.1 vs. 2.2 mm2) at 120-W, respectively. Regarding the laser fibre diameters, there were also no differences between the histologically measured parameters at 60-W in both Tm:fibre lasers. However, comparing the power of both lasers, the vaporization volume of the cw Tm:fibre laser at 60-W was significantly lower compared to 120-W using 200 and 600 µm fibres, respectively, whereas the high peak power pulsed Tm:fibre laser did not show significant differences at 60-W compared to 120-W with regards to the vaporization volume.
Conclusions : The laser fibre (200 or 600 µm) diameter did not affect vaporization volume, ablation depth, the thermo-mechanical damage zone and the coagulation zone in cw or high peak power pulsed Tm:fibre lasers. However, the cw Tm:fibre laser produces a coagulation zone five times larger than the high peak power pulsed Tm:fibre laser regardless of the fibre core diameter.