Combined Nd:YAG and Er:YAG lasers for real-time closed-loop tissue-specific laser osteotomy

Hamed Abbasi; Lina M Beltrán Bernal; Arsham Hamidi; Antoine Droneau; Ferda Canbaz; Raphael Guzman; Steven L Jacques; Philippe C Cattin; Azhar Zam

doi:10.1364/BOE.385862

Combined Nd:YAG and Er:YAG lasers for real-time closed-loop tissue-specific laser osteotomy

Biomed Opt Express. 2020 Mar 4;11(4):1790-1807. doi: 10.1364/BOE.385862. eCollection 2020 Apr 1.

Authors

Hamed Abbasi^{1

2}, Lina M Beltrán Bernal¹, Arsham Hamidi¹, Antoine Droneau^{1

3}, Ferda Canbaz¹, Raphael Guzman⁴, Steven L Jacques⁵, Philippe C Cattin⁶, Azhar Zam^{1

7}

Affiliations

¹ Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland.
² hamed.abbasi@unibas.ch.
³ Grenoble INP, Grenoble Alpes University, Phelma, France.
⁴ Department of Neurosurgery, University Hospital Basel, CH-4056 Basel, Switzerland.
⁵ Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA.
⁶ Center for medical Image Analysis and Navigation (CIAN), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland.
⁷ azhar.zam@unibas.ch.

Abstract

A novel real-time and non-destructive method for differentiating soft from hard tissue in laser osteotomy has been introduced and tested in a closed-loop fashion. Two laser beams were combined: a low energy frequency-doubled nanosecond Nd:YAG for detecting the type of tissue, and a high energy microsecond Er:YAG for ablating bone. The working principle is based on adjusting the energy of the Nd:YAG laser until it is low enough to create a microplasma in the hard tissue only (different energies are required to create plasma in different tissue types). Analyzing the light emitted from the generated microplasma enables real-time feedback to a shutter that prevents the Er:YAG laser from ablating the soft tissue.