With the passage of time, skin ages and accumulates photodamage. This results in loss of elasticity, changes in pigmentation, as well as the development of scarring from trauma, acne, or other insults. Laser skin resurfacing has become a mainstay of treatment for skin rejuvenation and restoration of the skin’s texture, tone, and elasticity. The most commonly used lasers include carbon dioxide (CO) lasers (10 600 nm), Erbium-doped yttrium aluminum garnet lasers Er:YAG (2940 nm), and erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er:YSCG) (2790 nm). For many years, CO2 lasers were the only lasers available for laser skin rejuvenation.
Er:YAG lasers were first FDA approved in 1996 for cutaneous resurfacing, and a comparative trial with CO2 lasers demonstrated that Er:YAG had equal efficacy with a trend shown towards more rapid recovery. Initially, short-pulse (SP) Er:YAG lasers were approved, with pulse lengths of 250-350 microseconds, however variable and longer-pulse (LP) Er:YAG lasers with pulse lengths of 500 microseconds to 10 milliseconds were subsequently approved in 1999. The long-pulse and variable-pulse lasers introduced in 1999 were designed to provide enhanced coagulation ability, reducing the side effects of bleeding, which occurred with shorter pulse Er:YAG treatment.
Anatomy and Physiology
The emitted peak wavelength of Er:YAG lasers is 2940 nm, which is closest to the absorption peak of water at 3000 nm. When an Er:YAG laser pulse is applied, the flashlamp-pumped crystal laser emits light, which is absorbed by water in the epidermis and papillary dermis. The water vaporizes, resulting in a skin-peeling effect in the epidermal layer. Thermal injury in the dermis stimulates the production of collagen, increased quantities of which can significantly improve the appearance of photodamaged skin while reducing visible rhytids and scars. Thus, Er: YAG lasers leading to a superficial ablation with the greatest energy absorption in the epidermis and papillary dermis. Furthermore, the vaporization of water produces a cooling effect, which decreases the amount of heat and damage to the surrounding tissues. This cooling allows Er:YAG lasers to be passed over the same skin and ablation area multiple times during the same treatment session without resulting in significant thermal damage and allowing for improved results with fewer treatment sessions.
Laser skin resurfacing treatments may be ablative or non-ablative. Ablative lasers damage and remove the superficial most layers of skin, which results in an improved appearance of the skin after subsequent re-epithelialization. Alternatively, non-ablative laser treatment does not remove the skin but nonetheless causes thermal injury, which stimulates the production of collagen and elastin. While ablative treatment has more significant results, non-ablative treatment is generally preferred due to its safer side effect profile. However, more treatments with non-ablative lasers are often required in order to achieve the same effect as a single treatment with an ablative laser. The 2940 nm wavelength of Er:YAG results in ablative treatment.
Laser treatment can be done by either full-field ablative therapy or fractional laser skin resurfacing. While a full-field approach treats the entire area of interest, fractional treatment ablates columns along the treatment area, while leaving intervening areas that are not touched by treatment. This leaves uninjured skin, which promotes re-epithelialization and reduces the occurrence of adverse side effects.
Er:YAG full-field laser skin resurfacing may be employed for treatment of actinic damage, dyschromia, rhytids, scarring, skin laxity, or even for improvement in coarse skin texture. Full-field treatment is usually limited to Fitzpatrick skin types I-II to reduce the occurrence of adverse effects; however, in some cases, Fitzpatrick skin types III-IV may be treated using more conservative parameters.
Patients treated with Er:YAG can experience visible improvement of facial rhytids 3 to 8 weeks following treatment. Periorbital and perioral rhytids are particularly amenable to treatment with Er:YAG laser resurfacing, and a significant reduction in the appearance of fine lines and wrinkles can be noted several months after field treatment to these areas. One or more passes over the desired treatment area can also improve skin texture and pigment irregularities. On histology, there has been shown to be an increase in dermal collagen 6 weeks post-treatment, suggesting a mechanism for improvement of the appearance of rhytids.
Er:YAG lasers have also been shown to be effective for the removal of benign, premalignant, and malignant skin lesions. Khatri et al. demonstrated that the SP Er:YAG laser could be used by applying for multiple passes over the candidate lesion until the lesion was no longer visibly apparent. This approach has also been shown to be effective for congenital melanocytic nevi in neonates and acquired melanocytic nevi in adults, although hyper- or hypopigmentation may result in the treated area. Seborrheic keratoses, achocondrions, and superficial intradermal cysts are also amenable to such spot Er:YAG treatment.
A thorough history and physical exam are required when evaluating patients as candidates for Er:YAG laser therapy. Before the initiation of treatment, patients must be fully informed of treatment risks and expectations, and also they should be assessed for contraindications to therapy. Contraindications include isotretinoin intake, radiation therapy, history of keloid, or presence of ectropion. Underlying cutaneous diseases at the treatment sites such as vitiligo should be considered. History should also include an account of sun exposure, sunscreen use, and family/personal history of skin cancers.
For spot treatment of cutaneous lesions, pulse lengths of around 10uM in-depth, and 10-40Hz/pulses per second are employed. Re-epithelialization of treated areas typically occurs within 4-7 days. Alternatively, field laser skin resurfacing can involve a small subregion (such as for small areas of acne scarring), regional (such as for the cheeks and forehead), or involving the entire area (as for full-face resurfacing). A treatment depth of 250uM is sufficient for generalized skin rejuvenation, while greater treatment depths of up to 1000uM are required for deeper scars caused by acne or traumatic insult.
Increasing duration of individual pulses during Er:YAG treatment results in increased tissue heating below the zone of ablation. While this can lead to improved clinical results, such as increased heating, has also been shown to be associated with an increased risk of adverse effects. Greater treatment density can result in more effective skin rejuvenation with fewer treatments. Increasing the overlap of pulse areas or passing over the treatment more than once during the treatment session can achieve greater treatment density.
The coagulation feature of the Er:YAG laser allows for greater skin tightening with reduced risk of bleeding. When multiple passes are used, the first pass is done in the “ablate” mode to remove the superficial layers of the epidermis and dermis and expose the underlying collagen in the dermis. Subsequent passes in the “coagulation” mode can achieve greater depth of ablation and thermal injury to the upper and mid-papillary dermis.
Superficial resurfacing can be achieved with a fluence of 5-10 J/cm or with a treatment depth of less than 250uM. This approach removes a very thin layer of the epidermis and can result in mild improvement in the appearance of photoaging with a shorter “down-time” and recovery period, as well as the decreased requirement of anesthesia. The increased energy of resurfacing from 5 to 10 J/cm can result in more erythema and discomfort but also achieves a greater clinical result.
Treatment with Er:YAG laser is carried out until the clinical endpoint is reached, indicating adequate treatment. Er:YAG laser endpoints include the appearance of petechial bleeding (indicating ablation entering the papillary dermis), a yellow color (termed chamois color), which indicates ablation of the midpapillary dermis) and visual effacement of rhytids.
Pre-operative care includes the use of local, regional, or general anesthesia can significantly decrease patient discomfort. General anesthesia or intravenous sedation may be required for larger treatment areas or more aggressive resurfacing treatments. Resurfacing of smaller regions, or treatments that are more superficial in depth can be accomplished with regional nerve blocks or local topical anesthetic. A topical anesthetic is used for nearly all treatments, with additional modalities added as needed.
Post-operative care involves covering the treatment area with a saline-moistened gauze immediately after treatment, followed by occlusive dressings with ointment or hydrocolloid to promote a moist wound healing environment until skin re-epithelialization is completed 5-7 days post-operatively.
Short term complications of Er:YAG therapy include the development of erythema and bleeding, as well as reactivation of herpes simplex virus infection. Changes in pigmentation and the development of scarring may also occur. Hypo- and hyperpigmentation are among the most common side effects of ablative laser therapy. As compared to carbon dioxide lasers, Er:YAG is considered less likely to cause hyperpigmentation of treatment areas, although some studies have demonstrated similar side effect profiles of the two modalities of laser skin resurfacing. Increased Er:YAG pulse duration has been shown to be associated with increased risk of pigment changes. Pigment changes may fade with the passage of time. Risks for prolonged post-operative erythema and pigment changes are greater in Fitzpatrick skin types III-IV. Other noted complications include the appearance of acne, milia, and dermatitis to the treated region.
Ocular injury is among the most serious complications that may result from Er:YAG laser treatment. The cornea is the most likely structure to be damaged. Ocular injury may be prevented with the use of ocular lubricant and corneal shields during treatment. Ophthalmology should be consulted in the event of corneal injury.
The risk for complications can be reduced by thorough pre-operative history and physical examination. Patient selection for candidates who may respond well to laser therapy is imperative. Patient education and primary prevention can also reduce risk. The importance of sun-protection in reducing the occurrence of post-inflammatory pigmentation changes should be emphasized. Patients should be educated on post-operative wound care, as well as informed about the normal postoperative course and changes that occur during healing. The risk for infection, scarring, and delays with healing should be clearly outlined.
Er:YAG laser skin resurfacing is an excellent treatment modality for a range of cutaneous indications, from spot treatment of lesions to full-field resurfacing. Emitting light at a peak wavelength of 2940nm, the 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 the production of collagen, reducing skin laxity and improving the appearance of static rhytids. With appropriate selection of candidates for treatment with Er:YAG lasers, patients can achieve an overall significantly improved appearance to their skin. It is most effective for Fitzpatrick skin types I-II but can also be employed for Fitzpatrick skin types III-IV with careful adjustment of laser pulse frequency and depth.
Not only is it effective as a stand-alone treatment, but it can also be combined with other techniques, including carbon dioxide laser treatment. The combined use of carbon dioxide and Er:YAG lasers have been shown to decrease crusting and pruritus following treatment as compared with treatment with CO2 lasers alone. Er:YAG laser therapy can also be an excellent adjunct to surgical treatments, including facelift surgery, blepharoplasty, and rhytidectomy.
Enhancing Healthcare Team Outcomes
A strong multi-disciplinary health care team can achieve optimal patient outcomes after treatment with Er:YAG laser resurfacing.
Thorough patient evaluation is essential for achieving optimal outcomes. Dermatologists, plastic surgeons, aesthetic physicians, and laser surgeons, when working together as a team, can perform a thorough evaluation to assess whether Er:YAG laser treatment would be appropriate in order to address patient concerns. Pharmacy and anesthesiology can provide recommendations for pre-operative and postoperative management.
Patient education on treatment procedure, pre-op, and post-op care, as well as clear expectations for results, are important to optimize outcomes for patients and health care providers. Nurses and physician assistants are experts in patient education and can provide patients with discussions regarding their concerns about the procedure.
Interprofessional health care teams for laser surgical treatments can maintain situational awareness regarding treatment progression and the possibility for complications, and can also initiate a rapid response to any adverse events. [Level]
Contributed by Ahmad M. Al Aboud, M.D., Perlita Perlac, BSN-RN, Anne Rose Encomienda, BSN-RN, Nidzma Ahaja, BSN-RN, Norhaya Nassa, BSN-RN.
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