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Lasers Med Sci (2013) 28:8792 DOI 10.1007/s10103-012-1078-3
ORIGINAL ARTICLE
A spectroscopic approach to monitor the cut processing in pulsed laser osteotomy
Konrad Henn & Gail G. Gubaidullin & Jens Bongartz &
Jrgen Wahrburg & Hubert Roth & Martin Kunkel
Received: 30 August 2011 /Accepted: 21 February 2012 /Published online: 9 March 2012 # Springer-Verlag London Ltd 2012
Abstract During laser osteotomy surgery, plasma arises at the place of ablation. It was the aim of this study to explore whether a spectroscopic analysis of this plasma would allow identification of the type of tissue that was affected by the laser. In an experimental setup (Rofin SCx10, CO2 Slab
Laser, wavelength 10.6 m, pulse duration 80 s, pulse repetition rate 200 Hz, max. output in cw-mode 100 W), the plasma spectra evoked by a pulsed laser, cutting 1-day postmortem pig and cow bones, were recorded. Spectra were compared to the reference spectrum of bone via correlation analysis. Our measurements show a clear differentiation between the plasma spectra when cutting either a bone or a soft tissue. The spectral changes could be detected from one to the next spectrum within 200 ms. Continuous surveillance of plasma spectra allows us to differentiate whether bone or soft tissue is hit by the last laser pulse. With this information, it may be possible to stop the laser when cutting undesired soft tissue and to design an automatic control of the ablation process.
Keywords Laser osteotomy. Spectroscopy. Pulsed laser
Introduction
In many surgical procedures, it is an important and necessary step to cut bones. A common practice is the use of an oscillating saw or rotating burrs which simply cut anything in front of the instrument. For some years, especially in the field of oral and maxillofacial surgery, the piezoelectric osteotomy technique has been used to avoid damage to vulnerable soft tissue (e.g., nerves and blood vessels) in close relation to the bone cuts. Due to the high frequencies and the minimal amplitude at the cutting edge, these piezo saws only cut hard tissues like bone and tooth, leaving any type of soft tissues untouched. The drawback of these systems is that they are somewhat sensitive to the skills of the surgeon and that they require abundant cooling which is not always...