18 February 2011 Interaction between high power 532nm laser and prostatic tissue: in vivo evaluation for laser prostatectomy
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Proceedings Volume 7883, Photonic Therapeutics and Diagnostics VII; 78831F (2011); doi: 10.1117/12.875535
Event: SPIE BiOS, 2011, San Francisco, California, United States
Abstract
A previous in vitro study demonstrated that 180W was the optimal power to reduce photoselective vaporization of the prostate (PVP) time for larger prostate glands. In this study, we investigated anatomic and histologic outcomes and ablation parameters of 180W laser performed with a new 750-μm side-firing fiber in a survival study of living canines. Eight male canines underwent anterograde PVP with the 180W 532-nm laser. Four each animals were euthanized 3 hours or 8 weeks postoperatively. Prostates were measured and histologically analyzed after hematoxylin and eosin (H&E), triphenyltetrazolium chloride (TTC), or Gomori trichrome (GT) staining. Compared to the previous 120W laser, PVP with the 180W laser bloodlessly created a 76% larger cavity (mean 11.8 vs. 6.7 cm3; p=0.014) and ablated tissue at a 77% higher rate (mean 2.3 vs. 1.3 cm3/min; p=0.03) while H&E- and TTC-staining demonstrated its 33% thicker mean coagulation zone (2.0±0.4 vs. 1.5±0.3 mm). H&E-stained cross-sectional prostatic tissue specimens from the 3-hour (acute) group showed histologic evolution of concentric non-viable coagulation zone, partially viable hyperemic transition zone of repair, and viable non-treated zone. H&E- and GT-stained specimens from the 8-week (chronic) group revealed healed circumferentially epithelialized, non-edematous, prostatic urethral channels with no increase in collagen in the subjacent prostatic tissue vis-á-vis the normal control. Our canine study demonstrates that 180W 532-nm laser PVP with its new fiber has a significantly higher ablation rate with a more hemostatic coagulation zone, but equally favorable tissue interaction and healing, compared with our previous 120W canine study.
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Reza Malek, Hyun Wook Kang, Steven Yihlih Peng, Douglas Stinson, Michael Beck, Ed Koullick, "Interaction between high power 532nm laser and prostatic tissue: in vivo evaluation for laser prostatectomy", Proc. SPIE 7883, Photonic Therapeutics and Diagnostics VII, 78831F (18 February 2011); doi: 10.1117/12.875535; https://doi.org/10.1117/12.875535
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KEYWORDS
Prostate

Laser tissue interaction

Tissues

Laser ablation

Fiber lasers

Collagen

High power lasers

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