Femtosecond Laser Ablation Behaviors of Bovine Bone With High Ablation Rate and Low Damage.

Abstract

Background and objective: The utilization of ultrafast lasers in bone material ablation is of paramount importance in minimally invasive surgical procedures. While ultrafast lasers are precise, achieving high efficiency and low thermal damage in bone ablation remains challenging.

Methods: This study investigates the ablation behaviors of bovine bone (storage in water) under different defocus distances using a femtosecond laser under ambient air conditions.

Results: The presence of bone canaliculi on the ablated surface indicates that the microstructure of the bone is well-preserved during laser ablation. The surface morphology and ablation area far beyond the heat-affected zone indicate that mechanical forces, rather than thermal effects from the femtosecond laser, were the primary factor in bone removal. The laser fluence and the overlap rate are pivotal in determining the ablation rate, which can be expressed in terms of cumulative laser fluence. The use of a scanning electron microscope (SEM) and a Raman spectrometer has revealed that no thermal damage occurs during laser ablation when the laser parameters are appropriately adjusted. It has been demonstrated that excessive cumulative laser fluence can result in thermal damage during continuous ablation.

Conclusion: The ablation method achieves a rate of 1.2 mm³/s with no thermal damage, which is comparable to that of the Er: YAG laser. The study thus establishes a threshold for a process that removes bone material with a high ablation rate and minimal damage, using a femtosecond laser.