MP29-06: A new surgical technology with femtosecond lasers towards no thermal injury in endoscopic surgery
Saturday, May 4, 2024 9:30 AM to 11:30 AM · 2 hr. (US/Central)
302B
Abstract
Information
Full Abstract and Figures
Author Block
Yutaro Tanaka*, Yudai Yoshimura, Osaka, Japan, Shuzo Hamamoto, Nagoya, Japan, Rie Tajiri, Osaka, Japan, Kazufumi Takano, Kyoto, Japan, Masashi Yoshimura, Osaka, Japan, Atsushi Okada, Sawatari-cho Mizuho-ku Nagoya, Japan, Kenjiro Kohri, Takahiro Yasui, Nagoya, Japan, Yusuke Mori, Hiroshi Yoshikawa, Mihoko Maruyama, Osaka, Japan
Introduction
In urological surgery, especially endoscopic lithotripsy, Holmium YAG lasers are commonly used. However, sever complications, such as ureteral stricture and ureteral injury, have increased because these lasers result in thermal injury due to photo-absorption by water. In addition, stone fragments scattered by strong shock waves obstruct operating field. In laser processing fields, it has been well known that near-infrared femtosecond lasers can achieve precise ablation of various materials (e.g., metals and organic materials) with much smaller thermal effects and less shock waves. This study aims to evaluate the lithotripsy characteristics of the femtosecond laser processing for establishment of novel endoscopic surgery.
Methods
Urinary stones (calcium oxalate, calcium phosphate, magnesium ammonium phosphate and uric acid) were collected from the patients. They were irradiated with femtosecond lasers (wavelength: 800 nm, pulse duration: ~100 fs) and Holmium YAG (wavelength: 2100 nm, pulse duration: ~20 µs) in ex vivo study (in air or water) (Figure A). After the laser irradiation, the stone cross-sections were examined using optical microscopy, scanning electron microscopy, and surface profilometry.
Results
Femtosecond lasers sharply cut urinary stones less retropulsion in both air and water regardless of stone composition (Figure A). In contrast, by Holmium YAG lasers, the stones were fragmented with strong shock waves and rapid increasing temperatures in water. Examination of the stone cross-sections revealed that femtosecond lasers produced smooth surfaces with micrometer-scale precision (Figure B, C), while Holmium YAG lasers produced rough surfaces due to thermal alteration.
Conclusions
This study successfully demonstrated precise cutting of urinary stones without significant thermal effects and shock waves by femtosecond lasers. These lasers offer the potential for a new endoscopic surgery that can safely cut tissues while minimizing thermal damage.
Source Of Funding
none
Author Block
Yutaro Tanaka*, Yudai Yoshimura, Osaka, Japan, Shuzo Hamamoto, Nagoya, Japan, Rie Tajiri, Osaka, Japan, Kazufumi Takano, Kyoto, Japan, Masashi Yoshimura, Osaka, Japan, Atsushi Okada, Sawatari-cho Mizuho-ku Nagoya, Japan, Kenjiro Kohri, Takahiro Yasui, Nagoya, Japan, Yusuke Mori, Hiroshi Yoshikawa, Mihoko Maruyama, Osaka, Japan
Introduction
In urological surgery, especially endoscopic lithotripsy, Holmium YAG lasers are commonly used. However, sever complications, such as ureteral stricture and ureteral injury, have increased because these lasers result in thermal injury due to photo-absorption by water. In addition, stone fragments scattered by strong shock waves obstruct operating field. In laser processing fields, it has been well known that near-infrared femtosecond lasers can achieve precise ablation of various materials (e.g., metals and organic materials) with much smaller thermal effects and less shock waves. This study aims to evaluate the lithotripsy characteristics of the femtosecond laser processing for establishment of novel endoscopic surgery.
Methods
Urinary stones (calcium oxalate, calcium phosphate, magnesium ammonium phosphate and uric acid) were collected from the patients. They were irradiated with femtosecond lasers (wavelength: 800 nm, pulse duration: ~100 fs) and Holmium YAG (wavelength: 2100 nm, pulse duration: ~20 µs) in ex vivo study (in air or water) (Figure A). After the laser irradiation, the stone cross-sections were examined using optical microscopy, scanning electron microscopy, and surface profilometry.
Results
Femtosecond lasers sharply cut urinary stones less retropulsion in both air and water regardless of stone composition (Figure A). In contrast, by Holmium YAG lasers, the stones were fragmented with strong shock waves and rapid increasing temperatures in water. Examination of the stone cross-sections revealed that femtosecond lasers produced smooth surfaces with micrometer-scale precision (Figure B, C), while Holmium YAG lasers produced rough surfaces due to thermal alteration.
Conclusions
This study successfully demonstrated precise cutting of urinary stones without significant thermal effects and shock waves by femtosecond lasers. These lasers offer the potential for a new endoscopic surgery that can safely cut tissues while minimizing thermal damage.
Source Of Funding
none