How does the Er:YAG laser work?

Er:YAG full-field laser skin resurfacing may be employed for the treatment of facial actinic damage, dyschromia, rhytids, scarring, skin laxity, or even for improvement in coarse skin texture.

Introduction

With the passage of time, skin ages and accumulates photodamage. This results in loss of elasticity, changes in pigmentation, and the development of scarring from trauma, acne, and other insults. Laser skin resurfacing has become a gold standard option for the rejuvenation of facial skin’s texture, tone, and elasticity. For many years, carbon dioxide (CO2) lasers (wavelength 10,600 nm) were the only lasers available for laser skin rejuvenation; nowadays, there are many more options, including the solid-state erbium-doped yttrium aluminum garnet Er:YAG (2,940 nm), and diode (810 and 940 nm).

Anatomy and Physiology

The emitted peak wavelength of Er:YAG lasers is 2,940 nm, which is closest to the absorption peak of water at 3,000 nm. When an Er:YAG laser pulse is applied, the flashlamp-pumped crystal lasing medium emits light energy, which is absorbed by water in the epidermis and papillary dermis, resulting in two effects that promote skin rejuvenation. The first is vaporization of the epidermis, which requires the dermal appendages (hair follicles and sweat glands) to resurface the skin in order to heal. Secondly, thermal injury in the dermis stimulates collagen production, which improves the appearance of photodamaged skin while reducing visible rhytids and scars. Furthermore, the vaporizing water acts as a heat sink, which decreases the amount of thermal damage sustained by the surrounding tissues. This cooling allows Er:YAG lasers to pass over the same target area multiple times during the same treatment session with a lower risk of causing a burn, providing improved results with fewer treatment sessions.

Contraindications

Contraindications to Er:YAG laser facial resurfacing include recent isotretinoin use (within the past 6-12 months), history of radiation therapy, history of keloid scarring, or presence of ectropion if the lower eyelid is to be targeted. Patients with fair skin (Fitzpatrick I-II) are good candidates for both fractionated and full field ablation, but darker-skinned patients (Fitzpatrick III-IV) should only undergo fractionated treatments. Patients with Fitzpatrick type V-VI skin should generally avoid Er:YAG laser skin resurfacing because of the high risk of post-procedure dyspigmentation. Patients with vitiligo may also be at a higher risk of developing post-treatment dyspigmentation. Conditions that inhibit or delay healing, such as diabetes and certain therapies for autoimmune diseases, are also relative contraindications for Er:YAG laser treatment. Lastly, patients with active infections, such as acne, cellulitis, impetigo, or herpes outbreaks, should wait until the infections are cleared to proceed with Er:YAG laser resurfacing.

Clinical Significance

Er:YAG laser skin resurfacing is an effective treatment modality for a range of cutaneous indications, from spot treatment of lesions to full-field resurfacing. Emitting light at a peak wavelength of 2,940 nm, the laser's energy is absorbed by water in the epidermis and dermis. Epidermal ablation and resultant re-epithelialization can treat actinic damage, dyschromia, and coarse skin texture. Thermal injury in the dermis below the zone of ablation stimulates collagen production, reducing skin laxity and improving the appearance of static rhytids. With an appropriate selection of candidates for treatment with Er:YAG lasers, patients can achieve significantly improved skin appearance. Er:YAG laser facial skin resurfacing is most effective for patients with Fitzpatrick skin types I-II but can also be employed for Fitzpatrick skin types III-IV with careful laser pulse frequency and depth adjustment.

Not only is the Er:YAG laser effective as a stand-alone treatment, but it can also be combined with other techniques, including CO2 laser treatment. The combined use of CO2 and Er:YAG lasers have been shown to decrease crusting and pruritus following treatment as compared to treatment using CO2 lasers alone. Er:YAG laser therapy can also be an excellent adjunct to surgical facial rejuvenation, including facelifting and blepharoplasty.