School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada.
National Nanotechnology Center, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia.
J Biophotonics. 2019 Jun;12(6):e201800293. doi: 10.1002/jbio.201800293. Epub 2019 Mar 14.
Ultrafast lasers are promising tools for surgical applications requiring precise tissue cutting. Shallow ablation depth and slow rate as well as collateral damage are common barriers limiting the use of laser in clinical applications. Localized cooling with water and/or air jet is known to reduce collateral thermal damage. We studied the influence of environmental conditions including air, compressed air flow, still water and water jet on ablation depth, ablation rate and surface morphology on bovine bone samples with an 800 nm femtosecond laser. At 15 J/cm , no thermal effect was observed by electron microscopy and Raman spectroscopy. The experimental results indicate that environmental conditions play a significant role in laser ablation. The deepest cavity and highest ablation rate were achieved under the compressed air flow condition, which is attributed to debris removal during the ablation process. The shallowest ablation depth and lowest ablation rates were associated with water flushing. For surface morphology, smooth surface and the absence of microcracks were observed under air flow conditions, while rougher surfaces and minor microcracks were observed under other conditions. These results suggest that ultrafast ablation of bone can be more efficient and with better surface qualities if assisted with blowing air jet.
超快激光器是一种有前途的工具，可用于需要精确组织切割的外科应用。激光在临床应用中的局限性通常包括消融深度浅、速度慢以及产生热副损伤。人们已知使用水和/或空气射流进行局部冷却可以减少热副损伤。我们使用 800nm 飞秒激光器研究了包括空气、压缩空气流、静水和水流在内的环境条件对牛骨样本的消融深度、消融率和表面形态的影响。在 15J/cm 时，电子显微镜和拉曼光谱没有观察到热效应。实验结果表明，环境条件对激光消融起着重要作用。在压缩空气流条件下，可获得最深的腔体和最高的消融率，这归因于消融过程中去除了碎片。水冲洗会导致最浅的消融深度和最低的消融率。对于表面形态，在空气流条件下观察到光滑的表面和无微裂纹，而在其他条件下则观察到较粗糙的表面和较小的微裂纹。这些结果表明，如果辅助使用空气射流，骨的超快消融可以更高效，并具有更好的表面质量。
