Ablative Laser Skin Resurfacing, in the simplest sense, describes the process of removing the epidermal and superficial dermal layers of the skin in order to reduce cutaneous signs of photoaging. Other indications for ablative laser skin resurfacing include patients who exhibit scarring, actinic keratoses, seborrheic keratoses, and facial wrinkles.
The use of laser for ablating and resurfacing involves the concept of selective thermolysis of the epidermal and dermal layers of the skin through the delivery of light energy  . Light energy, which is absorbed by the skin's two main chromophores, melanin, and water, then emit thermal energy causing destruction to the surrounding skin tissues.
The process of laser resurfacing has undergone a number of breakthroughs in the last few decades, with the first application of continuous carbon dioxide (CO2) laser beginning in the 1980s.
The implementation of pulsed CO2 lasers (versus continuous CO2 lasers) and the development of the erbium:yttrium aluminum garnet (Er:YAG) laser, which gained popularity in the late 1990s, further improved the precision and depth of cutaneous ablation and reduced the incidence of adverse effects .
Further refinement in skin resurfacing occurred in the early 2000s with the advent of fractional lasers, which are defined as lasers that use narrow, microscopic columns of laser light to treat a defined portion of the skin. This less destructive modality further reduced the incidence of adverse events and provided a greater degree of therapeutic control whilst still seemingly providing comparable results to non-fractional modalities.
Depending on the indication, the technician may choose to employ a specific ablative laser (e.g., CO2, Er:YAG) with a multitude of different settings, including fractional versus non-fractional, to achieve the desired result and more importantly, minimize laser-associated complications such as scarring, persistent erythema, and dyspigmentation.
All in all, ablative lasers represent a safe and effective tool for skin resurfacing, some nuances of which will be discussed herein.
A review and understanding of the function and anatomy of the skin and its appendages are important in order to thoroughly appreciate the applications of ablative laser therapy.As the body’s largest organ, the skin can be divided into several distinct layers including the epidermis, dermis, and hypodermis:
Within the ablative laser therapies, the two major laser types are CO2 lasers and Er:YAG lasers, with therapeutic options being subdivided into non-fractionated and fractionated laser ablation. Non-fractionated lasers will provide treatment over the entire targeted area of skin versus fractionated lasers, which will target therapy to specific fractions or columns of the targeted area to minimize the risk of adverse effects on the skin and hasten recovery. NOTE: The ablative lasers vaporize tissue and are generally considered more aggressive therapies and produce the most dramatic outcomes compared with nonablative lasers, which produce less dramatic improvements but leave the epidermis otherwise intact. Non-ablative lasers are beyond the scope of this review but can be useful to minimize the appearance of less prominent rhytides and dyspigmentation without a significant recovery period.
The laser will emit light at a particular wavelength, CO2 at 10600nm and Er:YAG at 2940nm which will be absorbed by the tissue's chromophores, namely water, and melanin. The goal is to ensure adequate but safe depth of penetration as well as delivery of sufficient energy to the targeted tissues while ensuring no excessive heat transfer to adjacent structures.
Energy delivery to tissues is directly correlated to the power of a laser, measured in Watts. Power density or fluency is the energy delivered per unit area and must be sufficient to achieve the desired effect while minimizing tissue damage . Excessive transfer of thermal energy particularly to the dermis can lead to adverse effects including scarring and dyspigmentation.
The depth of penetration of light energy is generally correlated with increasing light wavelengths. CO2 lasers generally produce a 20-60um depth of vaporization on the first pass compared with Er:YAG lasers that produce a 3-5um depth of vaporization on first pass . The advantage of CO2 and Er:YAG lasers is that they are highly absorbed by water in the epidermis, causing rapid vaporization of the epidermis ensuring the little light reaches the deeper layers of the skin. However, there is residual thermal damage caused by penetration of light which is believed to lead to collagen contraction, remodeling, and skin tightening. Thermal damage with traditional CO2 lasers and Er:YAG lasers is believed to reach depths of 100-150um and 10-40um respectively . The choice of laser often depends on a combination of clinician experience, patient factors, well as laser availability.
CO2 Ablative Lasers
The initial uses of laser ablation for facial rejuvenation began with the use of a continuous CO2 laser. The CO laser is an invisible beam that is primarily absorbed by water and emits energy at a wavelength of 10600nm. This makes this laser excellent for cutting, coagulation, and ablation of the skin. For instance, when it is pulsed at 5J/cm for <1ms, the light from the CO laser penetrates to a depth of approximately 20-30um . The development of high-pulsed CO2 lasers improved the ability to control the depth of ablation.
The CO2 lasers are thought to produce contraction of the skin immediately by denaturing collagen and subsequent stimulating the production of new collagen. Studies have demonstrated improvement in rhytides by up to 90% using CO2 laser therapy compared with surrounding untreated skin . The properties of the CO2 laser system work best at alleviating fine wrinkles especially around the eyes or mouth .
The discomfort associated with CO2 laser therapy often requires local anesthetic with additional sedation, anxiolytics, and possible oral analgesia  compared with a topical anesthetic alone for Er:YAG lasers. Recovery times associated with CO2 laser therapy are approximately two weeks with persistent erythema for a period of several weeks to months. Re-epithelization of the epidermal layer following CO2 laser therapy occurs approximately eight days  . Studies have demonstrated an improved clinical outcome and greater dermal collagen remodeling with CO2 lasers compared with Er:YAG laser on a per laser pass basis . However, CO2 lasers are associated with a higher rate of dyspigmentation compared with Er:YAG laser  . Photodamage is less severe in individuals with dark skin but laser-induced dyspigmentation is a major concern for darker skin individuals. For this reason, CO2 laser use is not recommended for skin phototypes IV or higher .
Fractional ablative laser therapy was first developed for CO2 lasers in 1998 with the Lumenis UltraPulse Encore . Fractional laser therapy uses narrow columns of laser light on the skin to create microscopic thermal zones measuring less than 400um in diameter and up to 1300um in depth. The concept relied on smaller treatment areas with viable surrounding tissue allowing for rapid re-epithelization as opposed to traditional laser therapy, which requires migration of epidermal cells. Compared to traditional CO2 lasers, fractionated CO2 laser therapy possesses similar efficacy as traditional CO2 laser therapy based on a number of studies demonstrating 80% of patients reporting an acceptable reduction in rhytides. Post-operative recovery is also more rapid than traditional CO2 laser therapy with a return to normal activity after 5-10 days depending on the intensity of treatment. In addition, post-operative topical hydroquinone cream, retinoids, or peeling agents may be prescribed to accelerate the resolution of erythema and edema .
Er:YAG Ablative Lasers
The erbium-yttrium aluminum garnet (Er:YAG) laser was developed in the 1990s and produces laser light at 2940nm. The chromophore is water, similar to the CO2 laser, with an absorption 12-18 times greater. Re-epithelialization of the epidermal layer occurs more rapidly as compared with CO2 lasers in approximately five days and 3-4 weeks of erythema post-operatively .
Er:YAG has a similar mechanism of action to traditional CO2 lasers but typically has less of a skin tightening effect. They additionally have a poorer coagulative effect than CO2 lasers which may limit multiple passes due to bleeding. Fluence levels of 5-15 J/cm are typically used for Er:YAG lasers although microablative procedures with lower fluences and a single laser pass may also have some benefit for treatment of photoaging.
Topical anesthetics are generally sufficient for Er:YAG laser procedure with the possibility of local anesthesia if needed . Shorter recovery periods are noted with Er:YAG laser compared to CO2 laser therapy with less postoperative edema and reduced adverse effects . Traditional Er:YAG laser therapy requires more laser passes than traditional CO2 lasers to achieve a similar depth of ablation. Long pulsed Er:YAG lasers have been used for as a less efficacious treatment of deep rhytides as a substitute for pulsed CO2 laser . However, outcomes are similar with some clinicians advocating superiority of Er:YAG compared to CO2 counterparts. The precise skin ablation with Er:YAG can be useful for areas at great risk for scarring such as periorbital skin with some clinicians opting for Er:YAG for dyschromia and fine wrinkles as opposed to deep rhytides . The more precise skin ablation with Er:YAG is sometimes desired but may also have reduced thermal damage to underlying collagen resulting in lesser skin tightening effect .
Fractional laser therapy for Er:YAG was developed and applied in a similar fashion to CO2 lasers. Postoperative and cosmetic outcomes were found to be similar to traditional Er:YAG . Although adverse outcomes such as scarring are less frequent than with CO2 lasers, they still occur with Er:YAG laser, and appropriate patient selection is required to minimize the risk of these events. For patients at high risk for dyspigmentation and scarring (Fitzpatrick IV-VI), Er:YAG would be preferred versus CO2. Of note, the reactivation and local spread of HSV may occur following any ablative laser therapy .
Indications for ablative laser resurfacing include:
Contraindications to ablative laser resurfacing include:
Laser-safe instruments (i.e., non-flammable)
Laser protocols, pre-op laser setting check
Gloves, mask, and cap should be used by all personnel
Povidone-iodine 5% solution (alcohol should be avoided because it is inflammable).
All personnel involved with ablative laser techniques should be properly trained with the use and safety related to laser technology. An assistant or nurse who will assist the primary operator with disinfection of the skin, preparation of topical anesthetic, operation of the laser, and recording of all anesthetic material used as well as patient vitals.
A detailed history and physical examination are obtained prior to proceeding with ablative laser therapy options.
Patients should be assessed for any contraindications (i.e. history of keloidal scarring, oral isotretinoin therapy, sites of scleroderma, radiation, etc.) prior to initiation of therapy. They should also be informed of the risks and a discussion surrounding expectations of therapy should take place with the provider in the pre-operative visit.
Pre-operative photographs should be obtained in the standard facial views (e.g., frontal, lateral, oblique, both smiling and non-smiling).
Prophylaxis with anti-virals including acyclovir, valacyclovir, or famciclovir is recommended to reduce the risk of reactivation of facial herpes infection, starting a few days before treatment and continuing for several days after.
Pre-operative topical tretinoin may help prime the skin for quicker healing after ablation
Prophylactic therapy for bacterial infections is controversial and not universally recommended.
The appropriate patient selection and informed consent regarding the expected risks and benefits of the period along with the anticipated recovery time is essential with ablative laser resurfacing and producing the best possible patient outcome and satisfaction.
There exists a paucity of well-designed data comparing the various CO2 and Er:YAG laser settings due to the small number of high-quality studies, the heterogeneity in various described laser protocols, and the elusiveness in defining a positive or successful treatment outcome. The specific technique employed is highly variable and coincides with the physician and chosen device and settings. Therefore, the reader is left to explore which laser (CO2 vs. Er:YAG) and associated protocol best fits his/her skill level, experience, and patients' expected outcomes. A discussion on the numerous calibrations used for both the CO2 and the Er:YAG is beyond the scope of this paper. With that being said, the following discussion will highlight some of the characteristics common to ablative laser skin resurfacing, regardless of the laser or protocol employed.
Ablative laser resurfacing should proceed as follows:
Ablative laser resurfacing represents a safe and effective technique that is associated with a low-risk profile and a high satisfaction rate.
Complications are associated with all types of laser including traditional and fractional lasers; though fractional laser resurfacing tends to have a reduced severity and frequency of complications including:
Ablative Laser Resurfacing is a useful tool to provide cosmetic improvements with regards to the treatment of photoaging, scarring, and superficial lesions of the skin. The CO2 and Er:YAG lasers remain the workhorse modalities for ablative therapies that can be personalized to the specific goal of treatment, the patient-specific factors, and the goals and expectations such as the anticipated recovery period. Compared to the non-fractionated, or full field lasers, fractiona; lasers represent a less invasive modality that can shorten recovery times while providing a similar therapeutic effect. Overall, ablative laser therapy represents a powerful tool for the cosmetic surgeon to maximize facial rejuvenation and aesthetic patient outcomes.
The key to maximizing outcomes and patient satisfaction is beginning with a thorough assessment with the provider and the patient. A discussion of the indications and patient expectations, as well as the anticipated outcome, recovery period, and risk is essential prior to initiation of therapy.
The success of the surgical procedure depends on an interprofessional team that utilizes physician assistants or nurses during the ablative laser procedure. This ensures having personnel who are comfortable and well trained to provide quality pre-operative, intra-operative, and post-operative monitoring and care.
Post-operative care and close follow-up are required to evaluate the patient for possible complications such as infection or dyspigmentation. Patient education on properly caring for the surgical site during convalescence is essential to mitigate adverse outcomes and maximize patient satisfaction. [LEVEL 5]
The appearance of edema and exudate can be expected within the first few postoperative days and the patient should be informed of this expected change in pre-operative counseling. The use of cooling compresses, saline/water soaks and head elevation will help minimize edema and keep the skin moist, which promotes wound healing. Skin cleansing and application of ointment should be done routinely until crusting resolves (3-4 days for fractional, 7-10 days for full field).
Pain associated with the post-operative period can typically be managed with acetaminophen with or without stronger oral analgesic agents. Patients must be counseled to avoid scratching or rubbing of the skin and to engage in photoprotective activities including avoidance of the sun and use of sunscreen to minimize the risk of persistent hyperpigmentation. Occasionally, pruritus may occur and the patient should be monitored and provided with topical corticosteroids to apply twice daily for several days if needed.
The use of topical steroids, hydroquinone cream, retinoids, or peeling agents has been employed to reduce the development of postinflammatory hyperpigmentation and to accelerate its resolution. Scarring can be managed with topical or intralesional steroids as well as nonablative fractional lasers to alleviate the cosmetic impact.
Patients are generally able to return to work 14-21 days following a full field face CO2 laser resurfacing, and 3-8 days following a full field Er:YAG laser. skin resurfacing. Fractional CO2 lasers are generally associated with a 4-10 day recovery period, while only 1-3 days off of work are required after fractional Er:YAG laser resurfacing.
Patients should be informed of the expected recovery time and monitored routinely to ensure normal post-operative healing by the interprofessional healthcare team.
Ensuring close follow-up during the initial post-operative period to monitor for signs or symptoms of infection, pruritus and other patient issues is imperative to ensure a reduction of peri-operative adverse outcomes and maximizing the therapeutic benefit of ablative laser therapy. It should be noted that many patients may require 1-3 treatments to achieve desired results so continual follow-up and discussion with the patient will be imperative to ensure the maximal chance for a positive clinical outcome.
|||Altshuler GB,Anderson RR,Manstein D,Zenzie HH,Smirnov MZ, Extended theory of selective photothermolysis. Lasers in surgery and medicine. 2001 [PubMed PMID: 11891730]|
|||Anderson RR,Margolis RJ,Watenabe S,Flotte T,Hruza GJ,Dover JS, Selective photothermolysis of cutaneous pigmentation by Q-switched Nd: YAG laser pulses at 1064, 532, and 355 nm. The Journal of investigative dermatology. 1989 Jul [PubMed PMID: 2746004]|
|||Ross EV,Grossman MC,Duke D,Grevelink JM, Long-term results after CO2 laser skin resurfacing: a comparison of scanned and pulsed systems. Journal of the American Academy of Dermatology. 1997 Nov [PubMed PMID: 9366815]|
|||[PubMed PMID: 8629842]|
|||[PubMed PMID: 15216537]|
|||[PubMed PMID: 29636145]|
|||[PubMed PMID: 21283923]|
|||[PubMed PMID: 23904818]|
|||[PubMed PMID: 19850197]|
|||[PubMed PMID: 7486737]|
|||[PubMed PMID: 8823015]|
|||[PubMed PMID: 18423256]|
|||[PubMed PMID: 11599402]|
|||[PubMed PMID: 20866114]|
|||[PubMed PMID: 10206045]|
|||[PubMed PMID: 15861082]|
|||[PubMed PMID: 21061766]|
|||[PubMed PMID: 18727019]|
|||[PubMed PMID: 10685094]|
|||[PubMed PMID: 11360460]|
|||[PubMed PMID: 20166156]|
|||[PubMed PMID: 16300226]|
|||[PubMed PMID: 20808594]|
|||[PubMed PMID: 17870524]|
|||[PubMed PMID: 29236557]|