Lasers in skin surgery

The most versatile laser used for skin procedures is a CO2 laser. It facilitates tissue dissection,spot or surface removal of pathological lesions by means of evaporation, and coagulation (in a defocused mode).

It is recommended to perform superficial evaporation of large skin areasby the CO2 laser with the shortest pulse duration (super pulse)for aesthetic reasons, since it significantly reduces thermal damage (coagulation) of surrounding tissue.The performance of the procedures covering a large skin area is much simpler and easier to standardise with the so-called scanners. These devices are co-operating with the laser by moving the beam at a predetermined speed along a fixed course.

Another laser used in the skin exfoliation procedures is an Erbium:YAG laser. It is characterized byless aggressive beam modalities which yield shallower penetration in comparison to the CO2 laser but consequently cause less residual thermal damage, which allows to avoid the risk of scarring. On the other hand, the Erbium:YAG resurfacing is less effective and the lack of coagulation results in poor haemostasis, which obstruct the wound dressing procedure.

The effects of resurfacing are positively correlated to the laser beam penetration depth.However, it should be borne in mind that increasing the penetration depth slows the epithelisation process and increases the risk of healing complications, including scarring. It was therefore sought to introduce laser methods of rejuvenating without damaging the skin. This proved to be possible by advancingand implementing the methods of cooling down the skin surface during laser treatments. Such procedures are called subsurfacing (from subcuticular resurfacing, which is resurfacing below the epidermislevel) or non ablative laser rejuvenation. For this purpose lasers with a wavelength of 585nm and 1450nm as well as IPL devices are employed, accompanied by an efficient skin cooling system. Both the CO2 and Erbium:YAG lasers destroy tissue by evaporation, regardless of its structure. A laser treatment that precisely targets specific tissue (e.g. blood vessels,birthmark or tattoo pigment, hair follicles) with a laser beam of specified parameters is called selective photothermolysis.It facilitates the selective destruction of the desired target, the so-called chromatophore, with minimum damage to other structures of the skin, i.e. with minimum risk of scarring. Recent years have brought the development of non-laser intense pulsed light (IPL) devicesof a specific light wavelengthobtained by placing colour filters, used to destroy certain chromatophores in accordance with the principles of selective photothermolysis.

The hair removal lasers include: alexandrite laser, Nd:YAG near infrared laser, diode lasers and IPL. The removal of pigmented nevi and tattoos is most commonly performed by means of the lasers with very short, nanosecond pulse duration (Q-switched): Nd:YAG, a laser with a wavelength of 755nm and a ruby laser.

The eradication of vascular tissue, where haemoglobin is the chromatophore,may be carried out with the following lasers: argon lasers, Nd:YAG with a wavelength of 532nm (KTP laser), dye lasers (dye lasers), diode lasers and IPL. Apart from standard application in haemangiomas removal, they may alsobe used for the treatment of other conditions, such as rosacea or hypertrophic, excessively vascularised scars. Excimer lasers with a wavelength of 308nm, whichfacilitate a very precise removal of tissue, are used in dermatology, for example in the treatment of vitiligo and psoriasis.

Fractional lasers (fraxel) selectively target a fraction of the skin at a time,which results in gentle rejuvenating without a prolongeddowntime. A separate issue is the use of lasers in cosmetic surgery procedures, where they are used as tools for incision, vaporization and coagulation of tissue. A typical example of such application is the so-called laser blepharoplasty, i.e. the cosmetic eyelid surgery performed by means of a surgical CO2 laser.