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Laser Skin Resurfacing
In writing the third edition of this book, it is amazing how some chapters change significantly, and others remain more similar. This chapter on laser skin resurfacing (LSR) has changed dramatically because the past 15 years have ushered in technological advances as well as improved and more predictable treatment protocols.
Lasers by definition are destructive devices and when used properly can create some of the most dramatic cosmetic and anti-aging changes. On the other hand, if used incorrectly, especially by novice users, lasers can create devastating side effects and complications including permanent disfigurement. One must always remember when treating a patient with a laser that we are creating a controlled burn. The control of such a burn is not necessarily the same from one machine to another or one patient to another. Significant variances in skin anatomy and physiology as well as inherent healing potentials for patients prevents “cookbook” treatment plans. As a note to novice practitioners, treating patients with laser is a skill and an art form and is not something that can be rushed. To become proficient, one must treat different patients with different types of skin and skin conditions and closely observe the healing process to fully understand what the laser does and how the patients heal.
It is human nature to desire the most dramatic improvements and therefore consider using the most aggressive laser settings. This can be a prescription for disaster in terms of LSR. I recommend that novice laser practitioners do the opposite; they should use the most conservative settings, closely watch and document the patient’s healing and progress and advance very slowly to more aggressive treatments and settings. Again, laser resurfacing can be a rewarding part of your practice, but it is also a highly litigated area for burns and complications. As I have said many times throughout this textbook, some cosmetic procedures require more art than science, and LSR can be one of these situations. To be successful, one must have an in-depth knowledge of skin histology, pathology, and healing potential. One must also understand the individual variances of various laser machines. Similar to microwave ovens, using the same setting on one machine may not provide the same result as another.
The acronym laser stands for l ight a mplification by s timulated e mission of r adiation. Laser technology in medicine existed decades before it became popular, but problems existed with the ability to ablate unwanted tissue without damaging surrounding normal tissue. With the improvement of technology and the understanding of photoscience and tissue response, lasers became a versatile treatment option. The basic principal of laser therapy is known as selective photothermolysis in which the chromophore is targeted with a pulse duration that is shorter than the thermal relaxation time, thus minimizing the risk for unwanted surrounding tissue damage. The development of the CO 2 laser (a wavelength of 10,600 nm) was initially used for surgical excisions but eventually was refined as a useful tool for skin rejuvenation and surgical incisions ( Fig. 13.1 ).
Laser wavelengths are shown on the electromagnetic spectrum. Note that lasers from the 500- to 800-nm wavelengths are visible and produce colored light, while lasers of the wavelength around the 800-nm region on the spectrum are invisible to the human eye.
The CO 2 laser produces tissue ablation and collagen shrinkage and is used to treat scarring, dyschromias, and numerous lesions. Although previous technologies such as dermabrasion and chemical peel exercised “an experienced guess” at tissue depth, the CO 2 laser was an instrument that could precisely ablate tissue at predictable depths. The CO 2 laser can ablate 50–150 microns of tissue with a zone of thermal damage up to 100 microns. The chromophore (target) for CO 2 laser is tissue water, and the laser energy is also absorbed by surrounding vessels and structures for unselective tissue destruction. This is different for other lasers that have chromophores of melanin or hemoglobin and are much more specific as to the tissue target. The earlier CO 2 lasers were continuous in nature, and it was more difficult to control lateral tissue damage. With the advent of ultrapulsed lasers and computerized pattern generators, high peak powers and short pulse duration were possible, which maximized tissue vaporization and minimized thermal injury. Laser treatment rejuvenates the skin by several actions. First, it vaporizes the epidermis and superficial dermis. This in and of itself is like stripping old wallpaper or pulling up old carpet. When the new skin reepithelializes, the patient has youthful skin in the place of the damaged skin. The thermal effect on the dermis creates new collagen (neocollagenesis). The new and more plentiful collagen also firms and rejuvenates the skin.
Historically, the early days of lasers in the 1990s were fraught with complications while surgeons attempted to harness this new technology and build learning curve. Much of what we take for granted today was hashed out by trial and error in those days. Earlier lasers were less controlled and automated.
In concert with progressing technology, many types of lasers were introduced to compete with CO 2 technology. The Erbium:YAG (Er:YAG) laser with a wavelength of 2940 nm became popular in the mid 1990s as a “safer and gentler” laser. This wavelength has a 13-fold greater affinity for water, of which the skin is about 70%. The stated advantages included less ablation depth, less thermal damage, faster healing, and decreased erythema persistence. Although this laser grew quickly in popularity after approval by the US Food and Drug Administration (FDA) in 1996, many of the same problems and complications associated with CO 2 lasers appeared soon afterward. Although the Er:YAG laser is still popular with some clinicians, the CO 2 laser is still the “gold standard” for skin rejuvenation, especially skin tightening and rhytid effacement. The operator must keep in mind that although a certain wavelength may be classified as “gentler,” it could still produce burns and disfigurement. It is more about how this “gentler” technology is applied that makes the difference. The race with laser technology is to have more favorable outcomes with lower treatment settings.
Fractional laser resurfacing has become extremely popular and will be discussed in depth later in this chapter. Fractional laser resurfacing is different from conventional full-coverage lasers in that only 80% of a given area on the skin is treated with the laser. This allows the 20% of untreated tissue to speed healing. Some clinicians feel that “old-school” traditional CO 2 treatment has been usurped by fractional laser treatments, but I disagree. Although the healing may be faster, the treatment is much less dramatic and requires multiple sessions. Ardent proponents of fractional lasers decry the 12–14 days of recovery required for CO 2 laser but perform 3–5 sessions of fractional treatments that require 3–5 days of recovery each time. The math simply does not add up. Although I understand that some patients simply cannot miss 2 weeks of work or play, repeating any procedure 3–5 times actually has a longer recovery. I also feel that the popularity of fractional laser is driven less by result and more by the fact that it can be sold to a far larger number of doctors than full-coverage ablative CO 2 lasers. The reason for this is that the average laser surgeon frequently does not have the training to perform sedation or access to general anesthesia. Fractional laser can be performed on awake patients (although I think all laser patients and surgeons do better with sedation), and because of this, companies can sell more lasers to a more diverse doctor base. Also, fractional treatments are easily delegated to physician extenders. Fractional laser treatment is “all around” easier, but in my experience is a compromise of the results obtainable from traditional CO 2 laser treatment. Having opined on this, it is fair to say that any laser technology that enables satisfactory, reproducible results on happy patients with low complications is a good platform. Fractional lasers are available in ablative and nonablative platforms. Ablative resurfacing literally vaporizes the tissue and removes it. Nonablative laser treatment damages or kills the cells without vaporizing them.
Over the past 25 years I have been very involved with CO 2 laser resurfacing and have discussed or featured numerous lasers in previous editions of this textbook. My goal with discussing any proprietary laser is not to promote the device or company but merely to discuss how I use that particular technology in my office. I have numerous CO 2 lasers in my office including the Lumenis Ultrapulse Encore laser ( www.lumenis.com ) and the Candela Core CO 2 laser ( www.candela.com ). I use these lasers interchangeably for various treatments; however, I use them as two distinctly separate devices that have different effects at different settings, and they are not interchangeable to a novice clinician. I have a truck and a sports car. I can drive either one to work, but they are uniquely different in what they do and their intended use. So, with this metaphor, all lasers can do similar things, but each one is a totally different device and must be learned as such.
As the last editions of this text focused more on the Lumenis Encore laser and treatments, I am focusing this edition on the Candela Core CO 2 laser platform as it represents more contemporary technology. Please understand that I could discuss ten major laser brands and companies that all have great products that can achieve similar results. The flavor of this text has always been “what I am doing now,” but it by no means implies that this is the only device or the only treatment. I am describing what has provided safe results with predictable outcomes in my office since the last edition of this text.
The Candela Core laser (henceforth referred to as the “Core” laser in this text) is an example of modern technology with advanced options of treatment settings, variable handpieces, and a modern user interface. Newer lasers have also become more compact and lighter ( Fig. 13.2 ).
Earlier lasers were bulky, heavy, and difficult to move around the office. The Candela Core CO 2 laser is representative of newer lasers that are lighter and more compact, as shown by the author lifting this device off the ground.
To further summarize, every practitioner should find at least one device to use that provides safety and predictable outcomes. Clinicians who become advanced in the use of laser technology may have numerous devices that they use for various specific treatments. Again, it would take an entire textbook to discuss all of the available laser devices.
Patient Selection
As with any cosmetic procedure, proper patient selection is the key to obtaining ideal results. Lighter skin types have the potential for more predictable skin resurfacing and fewer pigmentation problems. Although many skin classification systems exist, the Fitzpatrick system is the most widely used classification ( Table 13.1 , Fig. 13.3 ). This system is derived from skin response to sunlight and generalizations with hair and eye color and the amount of melanin in that particular skin type.
Table 13.1
Fitzpatrick skin classification
| Skin type | Skin color and characteristics |
|---|---|
| Ivory white | Always burns, never tans |
| White | Usually burns, tans minimally |
| White | Burns moderately, tans moderately |
| Beige/light brown | Burns minimally, tans easily |
| Moderate brown | Rarely burns, tans profusely |
| Dark brown/black | Never burns, tans profusely |
A plethora of skin type classifications exist, and with any of these systems there is always overlap. The importance is that the operator understands the significance of treating lighter skin tones, mid skin tones, and darker skin tones. All of these variances can have a lot to do with the ultimate safety and outcome of laser procedures. The Fanous classification is another useful scale. This system relates skin types to ethnic origin ( Fig. 13.4 ).
While using any type of classification system, the bottom line is that laser operators must understand that the pigmentation content in the patient’s skin can portend more potential resurfacing problems when using chemical peel and laser treatments. In my practice, I rarely use resurfacing procedures on Fitzpatrick IV, V, or VI skin types. These patients are more challenging and can develop significant hyperpigmentation and/or hypopigmentation that may be temporary or permanent. The lightest skin types, especially Fitzpatrick I and II classifications, are more predictable for resurfacing procedures and generally heal with fewer complications in terms of pigmentation abnormalities. It is the mid skin tones, mainly Fitzpatrick IV and V classifications, that can present the greatest pigmentation problems. These can include Asian, Hispanic, South Asian, and light-skinned African patients. There are practitioners and specific lasers that claim to be able to treat darker skin types (especially with fractional lasers), and this should be commensurate with the operator’s experience. Novice surgeons should begin with Fitzpatrick I and II skin types. It is important to remember that patients with significant skin pigmentation can be left with permanent hyperpigmentation or hypopigmentation, so all laser operators must understand the implications of light and dark skin when considering LSR.
Numerous computerized skin-scanning systems are available to diagnose various skin problems and can facilitate the diagnosis and treatment of laser patients. These vary from very expensive large platform machines to small, portable desktop devices like the Reveal imager ( canfieldsci.com ) I use in my practice ( Fig. 13.5 ). I am most interested to see how pigmented lesions enhance in the presence of ultraviolet light. Generally speaking, lesions that greatly enhance under ultraviolet light are superficial and very amenable to treatment ( Fig. 13.6 ). On the other hand, a brown spot on a patient’s face that does not enhance under ultraviolet light may implicate deep dermal pigmentation, which would not respond well to average laser resurfacing.
These types of devices are very useful for motivating patients to improve their skincare. Most patients do not realize the extent of their actinic damage and are frequently horrified to see such scans.
Laser Resurfacing Contraindications
Numerous contraindications exist for any type of skin resurfacing. A history of hypertrophic or keloid scarring, poor healing, and active conditions such as rosacea or acne may complicate skin resurfacing. Some skin diseases such as vitiligo, lichen planus, psoriasis, and verrucae can spread to traumatized skin. This is known as the Koebner phenomenon and although rare, can be problematic, such as when a patient with vitiligo on their body develops facial vitiligo after the trauma of laser resurfacing. Active herpetic lesions or a propensity of herpetic lesions or cold sores and active acne are relative contraindications. Previous radiation to an area can affect the pilosebaceous glands and affect healing. If there is any doubt about a patient’s ability to tolerate a laser procedure, a dermatology consult is in order. Care and close observation must also be used when treating patients who have had previous lower-lid laser and/or cosmetic blepharoplasty skin removal. These patients are subject to lower-lid malposition from the significant skin contraction that can occur after lasering. Patients with collagen vascular diseases such as lupus or scleroderma may have impaired healing mechanisms that could affect healing.
After the epithelium is destroyed by chemical agents or light sources, it must regenerate, or a full-thickness burn scar will result with only fibroblasts and no epithelium. Reepithelialization occurs from the base of the hair follicles from the pilosebaceous units, and the presence of the hair/sebaceous gland unit is directly related to how much and how quickly the new epithelium regenerates. In a process known as epiboly , the pilosebaceous units serve as the progenitors of new epithelium. New epidermal cells migrate from the base of the pilosebaceous unit, progress up the hair shaft, then spread laterally on the injured skin surface ( Fig. 13.7 ). Areas of the body that are heavily populated with pilosebaceous units have a better chance of more rapid epithelialization. The face has 30 times the pilosebaceous units as the neck or chest and 40 times the number on the dorsal arms and hands. For this reason, deeper peeling and laser treatment can be performed on the face, whereas the same treatment on the neck or extremities can lead to disastrous scarring. Areas heavily populated with hair follicles heal faster; with low hair-bearing areas, healing can be compromised.
The sincerest words of wisdom to novice surgeons who are just beginning skin resurfacing is to always respect the neck (and nonfacial skin), and never treat off-facial areas in an aggressive manner. I have served as an expert defense witness for multiple surgeons who caused significant scarring by peeling or lasering the neck. I have also had my own misadventures in this region, but luckily without permanent scarring. I learned to respect the neck early on in my experience and always pass this on to all novice surgeons. I have had my most sleepless nights worrying about resurfacing patients. Experienced surgeons will understand this statement.
Understanding the importance of pilosebaceous units and healing, any procedure or medication that affects or suppresses the pilosebaceous units could compromise healing and produce scarring. The mechanism of action of systemic retinoids such as isotretinoin (Accutane) is suppression of the pilosebaceous units, which would affect reepithelialization after skin resurfacing by peel or laser. Most authorities recommend waiting at least 1 year after Accutane therapy before laser resurfacing (6 months for a medium-depth chemical peel). Patients with collagen vascular diseases such as lupus or scleroderma may have impaired healing mechanisms and could affect healing.
Whereas preconditioning with tretinoin or bleaching agents is critical for chemical peeling to allow even penetration of acid, many practitioners do not precondition laser patients. In my opinion, patients with the potential for postinflammatory hyperpigmentation (PIH) will heal better when using precondtioning products. Whether they are required for laser treatment may be controversial, but there is no harm in using them.
Biopsychosocial Contraindications
Many factors can influence the patient’s healing experience besides physical and anatomic situations. Laser resurfacing is a procedure that takes less than 1 hour but carries a formidable recovery. The patient is basically raw with greasy, dead skin on their face and confined to the house during the period of reepithelialization, which can last up to 14 days. Unfortunately, many laser operators sugarcoat the recovery process. There is no better way to upset a patient or affect one’s reputation than to tell anything but the truth about the laser procedure. I have had full-face laser performed on my face on two occasions, and I can vouch for the hassle factor associated with this recovery. It also requires a lot of post-laser skincare that would include washing the face, applying various ointments, and performing vinegar soaks. Patients and their caregivers must take an active part in post-laser care, and patients should understand exactly what they are getting into. I think it is important for patients to see actual photos of how they will look at 1 day, 1 week, 2 weeks, and 1 month. This gives them an idea of what to expect. They must also understand what products they will need, and it is helpful to discuss makeup with the patient in the preoperative phase so they will be able to practice and be ready to cover their pink skin after reepithelialization.
I prefer to treat all full-face laser patients with an antiviral and an antibiotic. I generally prescribe valacyclovir 500 mg every 12 hours starting the day before surgery and ongoing for the next 5 to 7 days. I prescribe cephalexin for antibiotic coverage and use 500 mg every 6 hours beginning the day before surgery and lasting for 1 week. The use of tretinoin (Retin-A) and bleaching creams such as hydroquinone are controversial. Although they remain the standard of care for chemical peels, many laser surgeons do not use them. Although I do not routinely use these medications for my laser patients, there is no reason not to, and they will not have a negative outcome and may have positive attributes. I do not believe that there are evidence-based studies comparing their use and non-use with CO 2 laser. Because laser resurfacing involves such a formidable recovery that requires numerous medications, creams, and treatments, it can be confounding to the patient or caregiver; hence detailed instructions with the exact timing, doses, and treatments should be provided to the patient in written chart form. A video presentation on this is also valuable as the patient can watch this at any point during the recovery.
Laser Settings and Physics
As stated earlier, each brand of laser and each type of laser has different settings and parameters that affect the actual power output, skin wounding, and recovery. It is impossible to cover all of these settings for different lasers, and this chapter will try to generalize these settings and treatments. However, it is up to the operator to ensure experience and patient safety before attempting these procedures.
When discussing laser parameters, fluence is a very important measurement. Fluence is defined as the amount of energy received by a surface per unit area, which is usually expressed in joules per centimeter squared (J/cm 2 ). Many factors can influence the measurement of laser fluence including spot size and wattage of the laser. Most lasers have density controls that change the amount of overlap from a computerized pattern generator or laser handpiece. A low-density setting would be a fractional laser in which there is absolutely no overlap in spacing between the individual pulses. A high-density laser setting may have 100% coverage as well as overlap of the pulses. Some lasers have a setting for hertz (Hz), which is a measure of cycles per second of the laser beam, or how fast they are generated. When discussing laser treatment, operators frequently talk about single-pass or multiple-pass resurfacing. In general terms, a single-pass laser treatment would involve full coverage of the entire face as the total procedure. This is usually for fractional or lighter-penetration laser treatments. Multiple passes would indicate that after the first pass is completed a second or third pass is made with additional full-face treatments. This would be analogous to a single coat of paint on the wall versus multiple coats. In general, the greater the number of passes, the greater the lateral tissue damage and the depth of skin wounding, and the better the end result assuming normal healing. Multiple passes take longer to perform, require more intense wound care, take longer to heal, and can potentially produce more complications. Novice laser surgeons should begin with lower settings and single-past treatments until they experience the healing response of these patients.
Laser treatment must be personalized for each patient based on their age, amount of skin damage, pathology of damaged skin, skin thickness, quality of skin, and other parameters. Light to moderate skin damage generally requires superficial full coverage (or fractional) laser. Moderate to severe skin damage requires deeper treatment. The target and end point for each procedure is variable. For minor pigmentation, a basal layer treatment may be adequate. For deeper pigment and fine lines and wrinkles, the skin wounding must extend into the papillary dermis. For the deepest skin damage and dyschromias, the laser must extend into the reticular (deeper) dermis. Deep dermal treatment can cross the danger line if the treatment extends into the adnexa (hair follicles, sebaceous and sweat glands), and permanent scarring can result. The laser surgeon must remember that he or she is creating a large-surface second-degree burn of the entire face, which is about 5% of the body surface area, and this must be managed with great care.
The laser operator must have a firm understanding of the amount of skin damage provided by the proposed treatment. Although it is difficult to truly measure the penetration of the laser burn and related thermal damage, it can be generalized by understanding the histologic layers of the skin and the relative depth of penetration of the specific laser. Most lasers can predictably remove 50 to 100 microns of skin in a single pass, which would include almost all of the epithelium. The second pass may remove a similar amount of skin or have a little less penetration because of the desiccation of the skin after the first laser pass. Also important and directly related to the depth of treatment is the time required for reepithelialization after treatment. A basal layer laser treatment will heal in 4–6 days, while a reticular dermal treatment will take up to 2 weeks to heal. Wounds that take longer than 2 weeks to reepithelialize may heal with full-thickness scarring. Fig. 13.8 shows the tissue anatomy of the skin and the time required for reepithelialization after laser treatment.
Laser Safety
It should always be kept in mind that the main purpose of any laser is to damage the skin, so by definition these are dangerous devices. The use of lasers can be hazardous to the surgeon, staff, and patient. Every office should have a laser safety officer who is the staff member who enforces safety measures to protect all involved. Any time the laser is active, there are a number of things that must be done to uphold the standard of care for safety. Any interior windows in the operating room must be covered, and a sign must be displayed on the door that a laser is in use with the specific wavelength named. This ensures protection for anyone who may gaze through the window or wander into the room when a laser is in use that could produce retinal damage ( Fig. 13.9 ). Eye protection is paramount for the surgeon, staff, and patient. The CO 2 laser technically does not require protective eyewear as there is no visible light output potential for direct damage to the retina from viewing the actual wavelength. Eye protection must still be used in case the laser beam reflects off of a shiny object into someone’s eyes in the room (see Fig. 13.9 ). Keep in mind that mirrors within the laser reflect and direct the laser beam within the machine and articulating arm. The reflected beam from a shiny or reflective surface can produce the same or similar damage the cornea that it does on the skin. To prevent inadvertent beam reflection, most stainless steel laser instrumentation and eye shields have a flat, dull finish.
Vaporized particulate smoke inhalants are another potential laser hazard, and the smoke plume must be controlled and evacuated. Everyone in the operating room must wear a facemask and dedicated fine-pore laser masks are available and preferable (see Fig. 13.9 ). Care must also be taken that no one inadvertently steps on the activation pedal when the laser is on because this can trigger an unwanted laser beam that could cause a burn or fire hazard.
The placement of stainless steel corneal shields is an absolute requisite when using lasers that have any exposure around the face or eyes. Permanent corneal or other damage can occur in a split second and lead to permanent disability of the part of the patient as well as litigation ( Fig. 13.10 ). Placement of corneal shields is very simple. Several drops of commonly used local anesthesia (2% lidocaine with 1:100,000 epinephrine) are instilled in each eye for topical anesthesia and the stainless steel polished corneal shields are placed in the fornix of the lid first, using supplied suction cup holders. The upper lid is then elevated to accommodate the entire shield over the globe ( Fig. 13.11 ). Some patients have small palpebral apertures, therefore smaller corneal shields should be on hand as well.
It must be kept in mind that the CO 2 laser beam is also an ignition source and must not be used in the presence of confined oxygen. Operating room fires can cause severe injury and death. This is especially important when working around endotracheal tubes and nasal cannulas as they can ignite. The situation is more critical if cloth drapes are used around the head, which confines the oxygen. Any flammable material such as paper or cloth drapes, hair, or plastic also must be kept out of the path of the laser beam. Patients should not use hairspray or hair gel the morning of their surgery as these can ignite. Any flammable liquids such as alcohol or acetone should never be applied before laser or be unopened in the immediate vicinity of the laser beam. Some laser operators do not use Betadine for surgical prep because burning the dried iodine solution may release elemental iodine in the smoke plume, which is hazardous.
For isolated periorbital procedures, a Jaeger lid plate may be used in place of eye shields. This shoehorn-like instrument is placed in the lower fornix and adequately protects the globe for smaller or quicker procedures ( Fig. 13.12 ). When using any metal or plastic instruments inside of the eye, it is important to ensure that they are not thrown in with other instruments when sterilizing which could nick or scratch them causing damage the cornea with usage.
A true surgical team will embrace laser safety on every single laser procedure no matter how big or small ( Fig. 13.13 ) Mistakes happen when normal protocol is breached. Ensuring that the team has a laser safety officer in charge of the aforementioned safety procedures should be the responsibility of the surgeon.
Treatment Options
Although there are endless ways to classify laser treatments, I prefer the generalization of light, medium, and deep. Obviously, this would imply that one could have extra-light or extra-deep treatment, and we will discuss this as well. A laser is much like an exotic sports car in that it can go 30 miles per hour or 200 miles per hour. The supercar has this inherent ability to perform, but it is up to the operator to choose the correct speed for the conditions. Similarly, the laser operator must choose the correct laser setting and treatment depth based on the various factors previously discussed.
As stated earlier, it is impossible to discuss all settings on all available lasers. This chapter will focus on the Candela core laser. Most contemporary lasers are multifunctional in that they have the ability to provide a range of treatments from superficial to deep and from fractional to full-coverage. In general, “superficial” (light) laser treatments are restricted to the epidermis and are used for very minor wrinkling and dyschromias as well as for skin health. Light treatments heal in 3–5 days. “Medium” laser treatments treat to a depth of at least the basil layer of the epidermis or the papillary dermis. These treatments are for moderate wrinkling and dyschromias as well as skin health. These treatments heal in approximately 5–7 days. “Deep” laser treatments include the reticular dermis and are effective for deeper wrinkles and more severe dyschromias. Deep laser treatments heal in 10–14 days.
It is imperative that patients be informed of accurate recovery times. Unfortunately, some practitioners sugarcoat this situation. It is very unfair to a patient to have them take 1 week off from work, when in fact they needed 2 weeks. Honesty is the best policy, and in reality, it is better to overextend the predicted recovery than to attempt to downplay it.
Fractional Laser Resurfacing
Joe Niamtu, III
Although LSR has been a predictable part of cosmetic facial surgery for the past 25 years, new advances are made every year. Probably the single most popular advance over the past decade has been the introduction of fractional laser resurfacing. It is imperative to understand the difference between full-coverage and fractional laser treatment ( Fig. 13.14 ). Full-coverage treatment is traditional laser treatment in which a computerized pattern generator or handpiece treats the entire skin surface with overlapping pulses, destroying the entire treated skin surface. Fractional laser treatment, on the other hand, does not destroy the entire skin surface but rather produces spaced laser spots in an orderly fashion. These ablated columns are separated by non-lasered normal skin. Because the entire skin surface is not treated, reepithelialization and healing progress faster with fractional treatment. This can be explained to patients in a simplified fashion that full-coverage treatment is like painting with a paint roller and fractional treatment is like painting polka dots ( Fig. 13.15 ).
Fractional Overview
Rania Agha
Understanding fractional technology requires a basic understanding or the contemporary terminology, namely fractional, density , and energy . Fractional refers to the use of small yet separated beams (microbeams) that create skipped microthermal zones. Density refers to the distance between individual microthermal zones. Energy is the ability to create a microthermal zone expressed in Joules. The depths of the channels of the microthermal zones is the product of energy. Energy must be customized to the skin type, anatomic area, and condition that is being treated.
Mechanism of Action
Fractional laser resurfacing is based on a simple yet sophisticated concept. Resurfacing takes place in columns of 1 mm (for non-ablative) and 2.5 mm (for ablative) skin depth. The diameter of the microthermal zones varies from 100–200 microns, and the depth it penetrates can be up to 1600 microns perpendicular to the skin surface, bypassing the epidermis in non-ablative lasers. In other words, the injury pattern that is created by fractional phototheris unlike the one created by fully ablative, full coverage laser treatment (see Fig. 3.14 ). Several patterns can be used depending on the device. Different patterns are associated with different microbeam densities, and the energy delivered or fluence dictates the coagulation depth. The idea is that this will result in deeper dermal penetration, yet a lower risk for scarring and better ability to heal and hence less down time.
Historically, the Fraxel laser (Valeant/Solta, Bothell, WA) is the first device to be approved that uses fractional technology. The name Fraxel has been coined to the technology, and patients will often ask you if you use the Fraxel laser. It has been marketed heavily and has gained popularity because of its efficacy and minimal down time.
There are two types of fractional lasers: ablative and non-ablative. Non-ablative lasers bypass the epidermis and penetrate the dermis, and ablative lasers ablate the entire epidermis and treat into the dermis. Both ablative and non-ablative lasers achieve improvement and patient satisfaction; however, ablative resurfacing results in greater collagen and elastin stimulation, but with longer-lasting edema.
The clinical application of ablative lasers has been mainly for traumatic or acne scars, pigmentary changes (actinic or sun damage), and rhytids (wrinkles). Using the ablative wavelengths, the device uses water as a chromophore (target in the skin). The rise in water temperature inflicted by the laser results in ablation and coagulation with the outcome being neocollagenesis. Ablative lasers are typically reserved to patients of skin phototypes I–III. They account for a drastic reduction in wrinkles and pigmentation because they are aggressive. They may inadvertently result in prolonged erythema (redness) and permanent hyperpigmentation or hypopigmentation. Many agree that ablative fractional resurfacing may surpass traditional resurfacing for the purposes of skin tightening as it can achieve deeper dermal penetration of greater than 1500 microns, usually with a single pass, compared with continuous devices that necessitate several passes to achieve such a depth. Examples of ablative lasers are carbon dioxide (CO 2 ) with a 10,600-nm wavelength, erbium-doped yttrium aluminum garnet (Er:YAG) with a 2940-nm wavelength, and erbium-doped yttrium scandium gallium garnet (Er,Cr:YSGG) with a 2780-nm wavelength.
Non-ablative lasers are also indicated for rejuvenation, dyschromia, actinic damage, scars of different etiologies, striae distensae (stretch marks), and actinic keratoses. Studies that show significant skin tightening with non-ablative lasers have been equivocal. Non-ablative lasers are not recommended for lighter skin phototypes. These lasers are less destructive than ablative lasers and rejuvenate the skin by stimulating collagen production in the dermis; the epidermis is protected through skin cooling. Although less aggressive than ablative lasers, they do increase the thickness of the skin and stimulate dermal collagen production. This process occurs mainly by denaturing of proteins and collagen. The epidermis is bypassed by a cooling mechanism. After dermal penetration, the heat results in collagen coagulation followed by a course of healing.
Ablative lasers cause tissue evaporation and do not bypass the epidermis. The treatments are therefore more aggressive with a longer recovery course. The outcomes are clearly more satisfactory, resulting in greater rhytid reduction and improvement of scars and pigmentation.
Safety and Efficacy
Fractional ablative resurfacing has a higher safety profile than its traditional continuous counterpart. However, there have been numerous cases of scarring, pigment alteration (some permanent), infections, and patient dissatisfaction with fractional treatments. Traditionally, the neck and the eyelids are the anatomic sites associated with the highest risk for scarring. The neck lacks abundance of pilosebaceous units; therefore it lacks the ability to heal properly.
Indications
Fractional resurfacing is indicated for pretty much the same indications as continuous laser resurfacing. This includes but is not limited to rejuvenation and wrinkle reduction, skin tightening, actinic damage such as actinic keratoses or cheilitis, solar lentigos, seborrheic keratoses, or other types of keratoses such as stucco keratoses, adnexal tumors, acne scars, hypertrophic scars, and rhinophyma.
Patient Selection
A thorough preoperative history and physical examination is imperative. The visit starts with a patient interview. I usually start by having a general discussion with the patient, asking about them, who they are, their profession, and sometimes family. This puts them at ease. At this time, I would have observed their skin texture and tone, their facial movements and bony structure, as well as the hairline. I then ask them what is bothering them and what they would like to achieve. With the patient holding a mirror, they point at the areas in which they want improvement. I begin discussing the aging process, but first I pick one positive or youthful feature they have and point it out, whether it is a beautiful smile with healthy-appearing teeth or thick, beautiful hair. After I point to the areas that resurfacing can help with, I discuss the process at length, including the days beforehand, the day of the procedure, and the days after the procedure.
It is essential to ensure that the patient does not have any skin lesions that are suspicious for skin cancer. I have evaluated patients who came in for a cosmetic evaluation and ended up with non-melanoma skin cancers that necessitated Mohs surgery.
Ablative fractional resurfacing is reserved for patients with skin phototypes I–III (see Fig. 13.3 ). In my practice, I do not resurface patients who have skin phototypes IV and above. The risk for hyperpigmentation is higher, despite pretreatment with hydroquinone and retinoids.
Patients should undergo a complete clinical evaluation, including but not limited to any and all of the following:
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Medical history
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Specific collagen vascular or connective tissue disorders
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Koebnerizing skin diseases such as vitiligo, lichen planus, psoriasis, and verruca plana
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Psychiatric history
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History of herpes simplex eruptions
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Medications, especially those that potentially interfere with healing (e.g., immunosuppressive medications or isotretinoin)
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Allergies to medications or products
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Surgical history
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History of radiotherapy (which reduces adnexal tissues and results in risk for poor healing)
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Implantable devices
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Drug use
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Supplements of any kind
Laser Device
In my practice, the device that is used is the CO 2 RE laser (Candela Medical, Wayland, MA).
Device Description
The CO 2 RE system is a second-generation fractional CO 2 laser approved for skin resurfacing, ablation, coagulation, laser-assisted surgery (cutting), and female vaginal rejuvenation (see Fig. 13.2 ). The device has four different ablative modes: Light, Mid, Deep, and Fusion. The laser’s wavelength is 10,600 nm, with a laser beam energy range from 1–70 mJ. The system uses a sealed, all-metal carbon dioxide gas tube that is radiofrequency excited and air-cooled, emitting light at 10.6 nm with a programmable and customizable pulse duration and frequency.
Preoperative Procedures
Consultations are lengthy, and patients are given ample time to ask questions. If patients plan to get the treatment within 1 or 2 months, I advise them to get botulinum toxin treatments at the consultation visit. Relaxation of the facial muscles may permit better laser penetration, especially if the rhytids are deep. Patients are also prescribed tretinoin and hydroquinone to start pretreatment for at least 2 weeks. If need be, a prescription for valacyclovir is given, and patients are encouraged to purchase their postoperative products as well. These include a gentle allergen-free cleanser (Vanicream facial cleanser), a physical blocker–only sunscreen (ingredients: Zinc oxide, titanium dioxide, iron oxide), a barrier ointment (Vaseline, Aquaphor, or CeraVe healing ointment), white vinegar, Benadryl, and a wide-brimmed hat.
Patients are educated in detail about the procedure and the topical anesthetics that are used, and they are informed that nerve blocks will be performed as well. Photos are taken, and they are retaken on the day of the procedure. Informed consent is obtained and discussed in detail. This is one of the times that I discuss each line item in the consent form before signatures. One of my staff members is also present as a witness.
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