Erbium: YAG laser
The Erbium-YAG laser (also Erbium: YAG laser or Er: YAG laser ) is a type of laser widely used in medicine (dermatology; dentistry) that uses an erbium- doped YAG crystal as a laser medium . Due to its physical properties, the Er: YAG laser can be used to remove superficial structures or, in general, to “edit” them. This can be the removal of a superficial skin change. Due to the very superficial effect, tissue can be removed in a controlled manner, layer by layer. The thermal load on the adjacent tissue is lower compared to other types of laser (e.g. CO2 laser ), which leads to faster healing.
technical basics
The Erbium: YAG laser is a flashlamp-pumped solid-state laser. The wavelength of the laser light is 2940 nm. Due to its physical properties, the light of the erbium: YAG laser can only be poorly guided over glass fibers, but has to reach the handpiece via an articulated mirror arm. The wavelength corresponds to the absorption maximum of water, so that, together with the short pulse duration, very small volumes of tissue are heated extremely quickly (> 100 °) and thus vaporized explosively. This results in the ablation of the tissue layer in question. The absorption of the erbium: YAG laser in water is approx. 15 times higher than that of the CO 2 laser. Depending on the energy used, the thickness of the ablated layer is very thin (2–40 µm, depending on the energy set). The thermal necrosis zone is 10–40 µm, depending on the pulse length and energy.
application areas
dermatology
The Erbium: YAG laser can be used in the medical care of dermatological patients for many indications. Applications and results are highly dependent on the doctor's experience.
- Removal of solar keratoses (precursors of light skin cancer)
- Removal of seborrheic warts ("age warts")
- Opening of milia or closed comedones
- Removal or opening of nail material
- Removal of unpigmented, benign birthmarks or fibromas
- Removal of corns
- Smoothing of fine, superficial skin wrinkles (skin resurfacing, "laser peeling")
- Treatment of acne - or other scars
Dentistry
- Caries removal
- Cavity preparation
- Exposure of implants
particularities
The Erbium: YAG laser results in only a low thermal load on the skin layers adjacent to the treatment zone, which is due to the short duration of the laser pulse in combination with the very high absorption in the water of the skin cells. The slight heating of the tissue causes rapid wound healing, faster than with CO 2 lasers.
Due to the lower heat development on the tissue, in contrast to the similarly applicable CO 2 laser, capillary bleeding occurs when the upper areas of the so-called junction zone (dermo-epidermal transition) are reached. For the practitioner, this is a good orientation of the currently achieved ablation depth and avoids unnecessarily or undesirably deep ablation. On the other hand, the bleeding that occurs hinders the treatment of well-perfused structures. The erbium laser pulse is barely able to penetrate blood droplets, which makes further treatment impossible.
Skin changes caused by pathogens should not be treated with an Erbium: YAG laser, as pathogens (viruses, bacteria, fungal spores) can be transmitted to the area around the treatment area, but also to the air in the room and thus to the practitioner. In general, treatments with the Erbium: YAG laser should therefore be carried out with suction and a face mask. The suction also avoids the strong smell of the smoke gases (“like a farrier”), which arise during treatment with the Erbium: YAG laser. Skin changes that should not be treated include: B. therefore simple warts (Verruca vulgaris) and genital warts (Condylomata acuminata).
Treatments near the eyes can be carried out without any problems and without any risk to the eyesight, as the Erbium: YAG laser pulse cannot damage the eye. The layer of tears on the surface of the eyeball and also the eyeball itself, which consists mainly of water, in principle prevent the laser light from penetrating in the direction of the retina.
See also
literature
- C. Raulin, B. Greve: Laser and IPL technology in dermatology and aesthetic medicine , 2nd edition, 2003, ISBN 3-7945-2236-2
- M. Landthaler, U. Hohenleutner: Laser therapy in dermatology , 2nd edition, 2006, ISBN 3-540-30091-0