&lt;title&gt;Bone microsurgery with IR lasers: a comparative study of thermal action at different wavelengths&lt;/title&gt;

Romano, Valerio; Rodriguez, Regulo; Altermatt, H. J.; Frenz, Martin; Weber, H. P.

doi:10.1117/12.168016

Cited by 20 publications

(21 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…With a radiant exposure of H--12 J cm -2, the perforation of the cochlea with a thickness between 120 and 160~m (evaluated after the experiment by morphometry) was possible with 11-17 laser pulses, resulting in an ablation depth of 10 + 2/lm pulse-~ assuming a constant ablation rate for consecutive pulses (27). The diameter of the round hole was typically 350~m.…”

Section: Bone Morphology and Histologymentioning

confidence: 99%

Experimental in vivo fenestration of guinea pig cochlea using 2.79 Μm laser radiation

et al. 1997

View full text Add to dashboard Cite

Abstract. Erbium-YSGG laser systems are promising tools in ear, nose and throat (ENT) surgery. The high absorption in biological tissues, resulting in precise tissue ablation with minimal thermal tissue damage, and the possibility to guide the radiation through optical fibres make the 2.79 ~m wavelength a favourite for microsurgery.In order to simulate the fenestration of the human stapes foot plate required for prosthesis implantation when treating otosclerosis, five guinea pig cochleae were irradiated in vivo until perforation was achieved. The laser-induced temperature rise and pressure transients evoke activity in the inner hair cells that was investigated by micro-iontophoresis.Perforation of the cochlea bone (hole diameter of 350/~m) can be performed with a few laser pulses and high precision with a thermal damage zone of <100~m. The bone ablation rate is 10 + 2 ~m pulse -1 at a radiant exposure of 12 J cm-2. The functionality of the afferent inner hair cells in the guinea pig cochlea was verified before and after laser treatment using glutamate receptor agonists AMPA and NMDA. For the above selected laser parameters, the induced 15-min enhanced activity was blockable with the specific reversible AMPA and NMDA antagonists CNQX and AP-7.Micro-iontophoresis confirms the reversibility of cochlea functionality after its perforation with Er-YSGG laser pulses. A limit of radiant exposure around 12 J cm -2 is found for safe fenestration. It is demonstrated that the Er-YSGG laser is a precise and safe instrument whilst still using adequate laser parameters. On the other hand, this study demonstrates the potential of uncontrollable and unintended induced damage, resulting from vapour channel formation in the perilymph, if a high laser radiant exposure is applied.

show abstract

Section: Bone Morphology and Histologymentioning

confidence: 99%

Experimental in vivo fenestration of guinea pig cochlea using 2.79 Μm laser radiation

et al. 1997

View full text Add to dashboard Cite

show abstract

“…[12][13][14][15][16][17][18][19][20][21][22] Recent studies using pulsed TEA and RF-excited CO 2 laser pulses of submillisecond duration indicate that dental hard tissues can be ablated efficiently without generating peripheral damage. [23][24][25][26][27] Ivanenko et al 28 demonstrated that a mechanically Qswitched 10.6 μm CO 2 industrial laser could be used to cut bone rapidly at 300 Hz without thermal damage. The peak absorption of dental hard tissues occurs at 9.3 and 9.6-μm where the incident laser light will be absorbed at a depth of under 1-2 μm (see Fig.…”

Section: Introductionmentioning

confidence: 99%

“…29,30 Previous efforts focused on the 9.3 and 9.6-μm TEA lasers that employ a simple high voltage discharge to excite the gas mixture. [23][24][25][26][27]29,30 In contrast, Radio Frequency (RF) excited slab lasers use a radiofrequency source to excite the CO 2 gas and can be operated efficiently with a completely sealed gas mixture. The principal advantages of the RF-slab laser over the TEA laser are small size and sealed gas mixture.Systems with output in the range of 10-30 W are now available at relatively low-cost that do not require water-cooling.…”

Section: Introductionmentioning

confidence: 99%

Ablation of dental hard tissues with a microsecond pulsed carbon dioxide laser operating at 9.3-μm with an integrated scanner

2008

View full text Add to dashboard Cite

Pulsed carbon dioxide lasers operating at the highly absorbed 9.3 and 9.6-μm wavelengths with pulse durations in the microsecond range are ideally suited for dental hard tissue modification and removal. The purpose of these studies was to demonstrate that a low cost 9.3-μm CO 2 laser system utilizing low-energy laser pulses (1-5 mJ /pulse) delivered at a high repetition rate (400-Hz) is feasible for removing dental hard tissues. The laser beam was focused to a small spot size to achieve ablative fluence and an integrated/programmable optical scanner was used to scan the laser beam over the desired area for tissue removal. Pulse durations of 35, 60 and 75-μs were employed and the enamel and dentin ablation rate and ablation efficiency were measured. Laser irradiated human and bovine samples were assessed for peripheral thermal and mechanical damage using polarized light microscopy. The heat accumulation during rapid scanning ablation with water-cooling at 400-Hz was monitored using micro-thermocouples. The laser was able to ablate both enamel and dentin without excessive peripheral thermal damage or heat accumulation. These preliminary studies suggest that a low-cost RF excited CO 2 laser used in conjunction with an integrated scanner has considerable potential for application to dental hard tissues.

show abstract

“…Er:YSGG laser emission is coincident with the narrow (OH) absorption band at λ=2.8 μm while Er:YAG emission overlaps the broad water absorption centered at λ=3 μm. It is the generally accepted hypothesis that the subsurface expansion of water is the primary mechanism responsible for exfoliation or spallation of the enamel mineral at temperatures below the melting point of the tissue (~1200°C) during irradiation near λ=3 μm 7,9,10,12,16,[18][19][20][21][22] . During rapid heating, the inertially confined water can create enormous subsurface pressures that can lead to the explosive removal of the surrounding mineral matrix 11 .…”

Section: Introductionmentioning

confidence: 99%

“…During rapid heating, the inertially confined water can create enormous subsurface pressures that can lead to the explosive removal of the surrounding mineral matrix 11 . Several studies of hard tissue ablation in the λ=3.0 μm region indicate that large particles are ejected with high velocity from the irradiated tissue 7,9,10,20,23 . This observation strongly supports the mechanism of a water-mediated explosive process.…”

Section: Introductionmentioning

confidence: 99%

Near-IR imaging of erbium laser ablation with a water spray

et al. 2008

View full text Add to dashboard Cite

Near-IR (NIR) imaging can be used to view the formation of ablation craters during laser ablation since the enamel of the tooth is almost completely transparent near 1310-nm 1 . Laser ablation craters can be monitored under varying irradiation conditions to assess peripheral thermal and transient-stress induced damage, measure the rate and efficiency of ablation and provide insight into the ablation mechanism. There are fundamental differences in the mechanism of enamel ablation using erbium lasers versus carbon dioxide laser systems due to the nature of the primary absorber and it is necessary to have water present on the tooth surface for efficient ablation at erbium laser wavelengths. In this study, sound human tooth sections of approximately 2-3-mm thickness were irradiated by free running and Q-switched Er:YAG & Er:YSGG lasers under varying conditions with and without a water spray. The incision area in the interior of each sample was imaged using a tungsten-halogen lamp with a band-pass filter centered at 1310-nm combined with an InGaAs area camera with a NIR zoom microscope. Obvious differences in the crater evolution were observed between CO 2 and erbium lasers. Ablation stalled after a few laser pulses without a water spray as anticipated. Efficient ablation was re-initiated by resuming the water spray. Micro-fractures were continuously produced apparently driven along prism lines during multi-pulse ablation. These fractures or fissures appeared to merge together as the crater evolved to form the leading edge of the ablation crater. These observations support the proposed thermomechanical mechanisms of erbium laser involving the strong mechanical forces generated by selective absorption by water.

show abstract

<title>Bone microsurgery with IR lasers: a comparative study of thermal action at different wavelengths</title>

Cited by 20 publications

References 0 publications

Experimental in vivo fenestration of guinea pig cochlea using 2.79 Μm laser radiation

Experimental in vivo fenestration of guinea pig cochlea using 2.79 Μm laser radiation

Ablation of dental hard tissues with a microsecond pulsed carbon dioxide laser operating at 9.3-μm with an integrated scanner

Near-IR imaging of erbium laser ablation with a water spray

Contact Info

Product

Resources

About