Bovine cortical bone ablation by femtosecond laser (Conference Presentation)

Aljekhedab, Fahad; Zhang, Wenbin; Favero, Jonathan; Haugen, H.K.; Wohl, Gregory R.; Fang, Qiyin

doi:10.1117/12.2289331

Cited by 5 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results reported in this paper shows findings consistent with those reported by Aljekhadab et al [30] where an increased etch rate was reported with the use of airflow over the ablation sample. As well, [30] also demonstrated cleaner and more well defined edges of craters compared to water-layer assist and no assist fluid. The use of nitrogen has some key advantages in its potential use as an assist agent in ablation over other gases and liquids.…”

Section: Discussionsupporting

confidence: 93%

Optimization of laser osteotomy at 1064 nm using a graphite topical absorber and a nitrogen assist gas jet

Jivraj

Chen

Barrows³

et al. 2019

Biomed. Opt. Express

View full text Add to dashboard Cite

Laser ablation of bone for the purposes of osteotomy is not as well understood as ablation of homogeneous, non-biological materials such as metals and plastics. Ignition times and etch rate can vary during ablation of cortical bone. In this study, we propose the use of two techniques to optimize bone ablation at 1064nm using a coaxial nitrogen jet as an assist gas and topical application of graphite as a highly absorbing chromophore. We show a two order of magnitude reduction in mean time to ignition and variance by using the graphite topical chromophore. We also show that an increase in volumetric flow rate of the assist gas jet does show an initial increase in etch rate, but increased pressure beyond a certain point shows decreased return. This study also demonstrates a 2 nd order relationship between exposure time, volumetric flow rate of nitrogen, and etch rate of cortical bone. The results of this study can be used to optimize the performance of laser ablation systems for osteotomy. This is a companion study to an earlier one carried out by Wong et al. [Biomedical Opt. Express 6, 1 (2015)].

show abstract

Section: Discussionsupporting

confidence: 93%

Optimization of laser osteotomy at 1064 nm using a graphite topical absorber and a nitrogen assist gas jet

Jivraj

Chen

Barrows³

et al. 2019

Biomed. Opt. Express

View full text Add to dashboard Cite

show abstract

“…The results reported in this chapter show similar findings to that reported by Aljekhadab et al [155] where an increased etch rate was reported with the use of airflow over the ablation sample.…”

Section: Discussionsupporting

confidence: 91%

Penscriptive Depth-Controlled Robotic Laser Osteotomy

Jivraj¹

2021

Preprint

View full text Add to dashboard Cite

Bone cutting in surgery is currently done using un-intelligent tools that depend on the proficiency of the surgeon to prevent damage to underlying critical structures. As one can imagine, damage isn’t always prevented. Iatrogenic damage to dura and sub-dural neural structures during osteotomical procedures such as a craniotomy can result in increased patient morbidity. This dissertation proposes the development of a robot-guided laser osteotome (bone cutter) with the use of inline optical coherence tomography (OCT) to precisely control the cutting depth in real-time. The all-fiber system design integrates a high peak-power pulsed Yb-doped fiber laser (1064nm) coupled directly into the sample arm of a swept-source OCT system (λc = 1310nm) with a fourth-order power disparity between the OCT system and fiber laser. Sub-millimeter accuracy was achieved in percussion drilling of phantom and porcine bone. Through the use of optical topographic imaging (OTI), this work presents a novel method for the surgeon to identify arbitrary trajectories for desired cuts. A surgical pencil is used to demarcate cutting trajectories for the robot to follow directly onto the boney surface. OTI imaging combined with a novel algorithm developed through this work allows the penscribed line to be isolated and translated into spatial attitude information for the robot to guide the end effector-mounted laser along. Sub-millimeter trajectory following accuracy was achieved. This work also demonstrates the first use of OCT in continuous, real-time refocusing of the optical end-effector in order to maintain cut quality. The focus of the laser was able to be maintained within the Rayleigh length of the focused Gaussian beam for linear feed rates up to 1mm/s at a 45◦ surface incline. Finally, optimization of bone ablation is explored in this dissertation. The use of graphite as a high-absorption topical chromophore and the use of nitrogen as an assist gas in the form of a coaxial jet are both analyzed to determine how to achieve the highest etch rate in bone. The results in this dissertation show that the topical application of graphite was able to significantly reduce the mean and variance of etching performance; an improvement by at least two orders of magnitude in the time to 0.5mm etch depth is demonstrated. It is also demonstrated that etch rate during ablation can be optimized for coaxial nitrogen flow (30SCFH out of a nozzle with 3mm output diameter); higher and lower flow rates showed slower etch rates. It is hypothesized that a system such as the one developed in this dissertation will increase the precision of bone cutting, decrease the amount of time needed to make cuts into sensitive structures and also address certain issues of unsuccessful uptake of lasers in modern medicine.

show abstract

“…For instance, in the frame of bone tissue removal in surgical operations such as craniomaxillofacial surgeries, it is favorable to reach high-precision ablation while keeping the surrounding tissue the healthiest in order to favor the regeneration and the overall recovery of the tissue following the surgery. Femtosecond (fs) laser ablation is well-known to be characterized by negligible thermal effects on the material upon laser–matter interaction thanks to the very short laser pulse duration, which ends before the electrons may have time to thermalize and transfer the absorbed laser pulse energy to the lattice [ 6 , 7 , 8 , 9 ]. This specific property is of extreme importance when considering the interaction of light with biological tissues because the death of such tissues is a direct consequence of the tissue temperature increase and strongly prevents the tissue regeneration and the overall after-surgery recovery [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…The main issue linked to the full exploitation of such systems in the clinical environment remains the low ablation rate which can be achieved with respect to classical techniques such as mechanical approaches or even other types of laser sources [ 7 , 9 , 11 ]. Laser systems employed nowadays in the clinical environment for applications including enamel ablation in dentistry, skin ablation in dermatology and bone surgery are mainly quasi-continuous wave (QCW) or continuous wave (CW) Er:YAG laser systems running at a wavelength of 2.94 µm [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

Ablation of Bone Tissue by Femtosecond Laser: A Path to High-Resolution Bone Surgery

et al. 2021

View full text Add to dashboard Cite

Femtosecond lasers allow for high-precision, high-quality ablation of biological tissues thanks to their capability of minimizing the thermal loads into the irradiated material. Nevertheless, reported ablation rates remain still too limited to enable their exploitation on a clinical level. This study demonstrates the possibility to upscale the process of fs laser ablation of bone tissue by employing industrially available fs laser sources. A comprehensive parametric study is presented in order to optimize the bone tissue ablation rate while maintaining the tissue health by avoiding excessive thermal loads. Three different absorption regimes are investigated by employing fs laser sources at 1030 nm, 515 nm and 343 nm. The main differences in the three different wavelength regimes are discussed by comparing the evolution of the ablation rate and the calcination degree of the laser ablated tissue. The maximum of the ablation rate is obtained in the visible regime of absorption where a maximum value of 0.66 mm3/s is obtained on a non-calcined tissue for the lowest laser repetition rate and the lowest spatial overlap between successive laser pulses. In this regime, the hemoglobin present in the fresh bone tissue is the main chromophore involved in the absorption process. To the best of our knowledge, this is the highest ablation rate obtained on porcine femur upon fs laser ablation.

show abstract

Bovine cortical bone ablation by femtosecond laser (Conference Presentation)

Cited by 5 publications

References 0 publications

Optimization of laser osteotomy at 1064 nm using a graphite topical absorber and a nitrogen assist gas jet

Optimization of laser osteotomy at 1064 nm using a graphite topical absorber and a nitrogen assist gas jet

Penscriptive Depth-Controlled Robotic Laser Osteotomy

Ablation of Bone Tissue by Femtosecond Laser: A Path to High-Resolution Bone Surgery

Contact Info

Product

Resources

About