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Hypothesis: Of techniques currently available for facial skin appearance improvement, nonablative laser therapy offers subtle improvements with an excellent risk-benefit ratio.
The subtle improvements in skin texture and wrinkling after nonablative laser treatment are preferred by many patients to the more obvious improvements after ablative laser resurfacing, because the nonablative laser treatment has a lower risk of complications, shorter recovery time, and less disruption of regular activities. In 1993, the first high-energy resurfacing carbon dioxide lasers became available for skin resurfacing. These carbon dioxide resurfacing lasers effectively treat facial rhytids and actinic changes.1,2 They are used to ablate the epidermis and partially ablate the dermis, removing skin changes due to photoaging. They stimulate neocollagen formation and tissue tightening,3,4 resulting in long-term skin texture and wrinkle improvement.
Paul J. Carniol, MD
Brad A. Greene, MD
These and subsequent resurfacing lasers have continued to use high fluence (power density) coupled with a short pulse duration or a scanning mechanism to achieve similar improvement. These lasers, classified as ablative because they remove epidermis and some dermis, rapidly vaporize the skin’s surface with relatively minimal adjacent tissue injury. They differ significantly from the prior surgical carbon dioxide lasers, which used lower fluence and either continuous or interrupted laser energy. Their significantly longer dwell time caused greater tissue trauma and a greater adjacent zone of thermal necrosis.
As surgeons gained experience with carbon dioxide lasers by 1995, they also noticed the typical long recovery time (prolonged erythema) and associated complications. At that time, one of us5 initiated a technique alteration to decrease the risks of carbon dioxide laser resurfacing and reduce recovery time. Laser surgeons had been advised to resurface down into the reticular dermis until a uniform chamois appearance was achieved. Using the new technique, resurfacing was continued only down to the necessary depth to treat thecondition or until a chamois appearance occurred. Surgeons were still cautioned not to resurface after the chamois appearance was present, even if the condition was not completely eradicated. This revised technique reduced the incidence of postresurfacing scarring and delayed hypopigmentation and eased postresurfacing recovery. Within a year, this new technique was adopted by many practitioners.
By 1998, the erbium:YAG laser was also being used for resurfacing. Comprehensive publications on laser skin rejuvenation provided information about both types of lasers.6,7 The erbium laser is effective for treating milder rhytids and photoaging.8 Compared with carbon dioxide resurfacing lasers, it causes less adjacent thermal injury and has a shorter recovery time and less neocollagen formation. Recovery time after resurfacing with the short-pulse-duration erbium laser is influenced by resurfacing depth and the particular laser and technique used. Significantly less collagen contracture occurs than after carbon dioxide laser resurfacing.9
To attempt improvement of erbium laser effectiveness and the neocollagen formation, erbium lasers with both short and longer pulse durations were developed. The longer pulse duration causes greater adjacent thermal injury and greater stimulation of neocollagen formation. Healing time is longer after longer-pulse-duration erbium laser treatment than after short-pulse-duration erbium laser treatment. Even though longer-pulse-duration erbium laser stimulates more neocollagen formation than a short-pulse-duration erbium laser treatment, it is still less than after carbon dioxide laser treatment.10
Initially, the laser resurfacing procedures described herein were very popular. As physicians and patients became aware of the potential prolonged recovery process, which often included weeks of pinkness, the demand for treatment with these lasers diminished. Nonablative lasers (lasers that do not remove epidermis but work through intact skin) were developed for attempting facial skin appearance improvement by stimulating neocollagen formation without the recovery period associated with resurfacing lasers. Nonablative laser technology has since become widely available.11 Currently, technology used for nonablative skin rejuvenation includes the CoolTouch laser (CoolTouch Inc, Roseville, Calif),12-14 Visage radiofrequency (ArthroCare Corp, Sunnyvale, Calif),15,16 the DioLite Laser (Iridex Corp, Mountain View, Calif),17 1540-nm erbium glass laser,18 and intense pulsed-light sources.19,20
More recently, the 1450-nm SmoothBeam laser (Candela Laser Corp, Wayland, Mass) has also become available for nonablative collagen stimulation.21 This laser uses a series of alternating dynamic cooling pulses and laser pulses. In one study,21 it was found to be more effective than dynamic cooling alone for treatment of rhytids. In another study,22 the feasibility of this laser for treating active acne was demonstrated. Additional studies are currently under way using this laser. Of the other technologies now available for facial skin rejuvenation, some are laser based, and others are not.
A radiofrequency device (Visage; Arthrocare Corp) makes available a process called coblation.15,16 During coblation, a radiofrequency current passes through isotonic sodium chloride solution, causing formation of an ionized plasma, which strikes the tissue surface, breaking the molecular bonds. Typically, the first pass of coblation removes the epidermis. The second pass extends approximately 50 μm into the dermis.15 There is still controversy as to whether additional passes increase the depth of coblation resurfacing or cause increased adjacent thermal effects without additional ablation.
In the experience of one of us (P.J.C.), this device removes superficial rhytids and can also reduce the depth of deeper rhytids. Typically, after coblation, the facial skin pinkness lasts for 1 to 3 weeks. Thus, posttreatment recovery is briefer than after carbon dioxide laser resurfacing. Pinkness during the recovery period is milder than after carbon dioxide laser resurfacing and easier to conceal with makeup. As with any resurfacing procedure, there is some risk of complications. One of us (P.J.C.) has had a patient with transient postinflammatory hyperpigmentation. A case of hypertrophic scarring, which resolved with treatment, has also been reported.16
In the past 9 months, a new device has become available, using radiofrequency energy to tighten facial skin. It does not alter the appearance of the skin surface. Thus far, there is a preliminary report,23 based on research supported by the manufacturer (Thermage Inc, Hayward, Calif), about the efficacy and complications related to this radiofrequency device. In this report, 14 of 15 patients achieved some facial skin tightening.
Intense pulsed light has been used to improve the appearance of photodamaged and photoaged skin by nonselective absorption of noncoherent light by epidermal and dermal pigment. In addition, intense pulsed light has been used to treat facial pigmentation and pinkness. It may be that enough heat energy is delivered to the dermal fibroblasts to stimulate increased collagen production.20 In another study,24 no difference was noted in the amount or quality of collagen between treated and untreated areas. These authors found a decrease in Demodex species in the treated areas and theorized that perhaps this was responsible for the observable clinical improvement.
Most nonablative lasers are designed to preserve the epidermis while inducing a dermal thermal injury. Typically, the epidermal surface is protected by cooling, whereas the dermis is heated by the laser to induce the thermal injury. This stimulates the dermal fibroblasts to produce neocollagen gradually over several months following the procedure. The keys to accomplishing these results are as follows: (1) energy delivery can be spread over multiple pulses; (2) energy can be focused to the desired depth, usually 100 to 400 μm from the skin surface; and (3) selective epidermal cooling at the site of energy delivery can prevent epidermal injury. A potential alternative nonablative method is to heat the dermal vasculature and stimulate elastin formation.19
The CoolTouch laser was the first nonablative laser widely available. This laser uses a solid-state, pulsed, Nd:YAG, 1320-nm wavelength laser. The energy output is a pulse waveform of three 300-microsecond pulses delivered at 100 Hz. The total energy output of the resultant 20-millisecond macropulse (fluence) can be adjusted up to 39 J/cm2. The hand piece is designed to deliver energy through an optical fiber and focusing lens that creates a spot size of either 5 or 10 mm in diameter, depending on the hand piece chosen. In addition to its laser-delivery function, the hand piece houses a built-in cryogen spray unit for dynamic epidermal cooling (tetrafluoroethane); this can be timed for either prelaser or postlaser cooling of the epidermis. The hand piece also embodies an infrared thermal sensor to monitor the skin surface temperature. The goal of each combined laser and cryogen pulse is to achieve a dermal temperature (at 100 μm depth) of approximately 60°C to 70°C, whereas the preenergy or postenergy delivery cooling effect of the cryogen pulse maintains epidermal temperatures between 40°C and 49°C.
A topical anesthetic such as lidocaine and prilocaine (EMLA cream; Astra Pharmaceuticals, Wilmington, Del) is used to minimize discomfort with CoolTouch laser treatment. The number of passes, fluence, and peak temperature are adjusted for each patient, depending on clinical response and degree and length of erythema after each treatment. The optimal duration of erythema after each treatment should be from 1 to 4 hours. Patients can usually return to regular social activity the following day.
Before performing CoolTouch laser treatment, it is important to discuss with the patient the limitations and the variability of the results. Patients should also be aware that improvements will take place over a period of months after the treatment is completed. Maintenance treatments may be required every 6 months after the initial series if optimal results are to be maintained (Figure 1).
A patient treated with the nonablative CoolTouch laser (CoolTouch Inc, Roseville, Calif). She has visible improvement in her periorbital rhytids.
Other lasers for nonablative collagen stimulation are becoming available. The 1450-nm SmoothBeam laser, which also uses dynamic cooling, was found to be more effective than dynamic cooling alone for treatment of rhytids in one study.21 In another study,22 the feasibility of this laser for treating active acne was demonstrated. Additional studies are currently under way to evaluate this laser, including a recently completed study (P. J.C., unpublished data, 2003) that uses combined modalities for treatment of acne scars.
In one study,18 the 1540-nm erbium glass laser produced mild-to-moderate clinical improvement in the periorbital and perioral regions. The periorbital region with the thinnest skin was the most responsive. This article noted, as have others, that there is a lack of correlation between the histological changes in the dermis and observed clinical change.
Currently, the most common and most successful areas treated with these nonablative lasers are the periorbital and perioral areas. Typically, treatment with these nonablative lasers gives a moderate improvement in the depth and length of rhytids. This requires a series of 4 to 6 treatments spaced approximately 4 to 6 weeks apart. Deeper rhytids with dermal atrophy in addition to an epidermal component usually do not show significant clinical improvement. The chances of improvement are increased if rhytids can be effaced with finger stretching. Another study,17 under review, demonstrated a 25% improvement in the appearance of rhytids in 70% of patients using a long-pulse, 532-nm laser.
Nonablative lasers offer significant advantages over the earlier resurfacing lasers. Although resurfacing lasers effectively treat facial photoaging skin changes, their popularity has diminished owing to the associated recovery morbidity and duration of recovery. In the experience of 1 of us (P.J.C.), many patients do not want to deal with the required wound care or lose time from their daily activities during the postresurfacing recovery period. They also do not want to risk the potential postresurfacing complications, which can include, but are not limited to, erythema or dyschromia.
Most patients either work or have very busy schedules. Whenever the options for treatment of their facial wrinkles are discussed, most prefer nonablative technology, even considering the limitations of achievable results. One of us (P.J.C.) has recently completed an institutional review board–approved study to assess whether a better result can be achieved by combining a nonablative laser with other modalities. Most patients can continue their regular activities while undergoing treatment with nonablative techniques.
Typically, nonablative procedures are performed using only topical anesthesia in the physician’s office. Patients do not require any injection of local anesthesia, intravenous anesthetic agents, or general anesthesia, which is also appealing to the patients. After each treatment, patients generally experience only mild pinkness, which resolves relatively quickly after the procedure. For many patients, the pinkness lasts less than a few hours but can infrequently last up to 72 hours. Because the epidermis is preserved, there is a smaller risk of complications such as scarring or dyschromia than after laser resurfacing.
The rapid proliferation of nonablative lasers should stimulate further improvements in the devices and their treatment results. Patients undergoing nonablative procedures are usually self-selected and are willing to accept lesser results than can be achieved with resurfacing lasers. Due to this patient demand, we note that less invasive nonablative procedures are replacing ablative procedures.
When nonablative lasers are used, the results are subtler and not as predictable as those achieved with a resurfacing laser. Because the results are caused by stimulation of the patient’s neocollagen production, improvements appear slowly over a period of months. Depending on patient expectations, particularly if the patient anticipates a result comparable to laser resurfacing, the less dramatic results from nonablative lasers can be disappointing. Currently, nonablative lasers are not as effective for treating deeper rhytids as resurfacing lasers. Ablative resurfacing lasers are predictable and effective. Currently, the available resurfacing technologies include the carbon dioxide laser, the erbium laser, and a radiofrequency device (Visage; Arthrocare Corp).
The carbon dioxide laser is the most effective laser for ablating actinic changes and rhytids that extend into the reticular dermis. The carbon dioxide laser wavelength is absorbed by water (its chromophore); since water is present in all tissues to a varying degree, laser absorption is limited only by its depth of penetration. During tissue ablation there is a significant heat energy transfer into the adjacent tissues. This is important, since in addition to ablating tissue, this laser leaves a zone of adjacent thermal injury. This adjacent thermal injury causes greater collagen contracture and simulation of neocollagen. Thus, the benefits of carbon dioxide laser resurfacing extend beyond the depth of ablated tissue. There is a greater improvement than would be anticipated from the tissue ablation alone.
However, when used alone, this laser is associated with the longest period of postresurfacing erythema (Figure 2). Some physicians have achieved a shorter duration of postresurfacing erythema by following the carbon dioxide laser passes with 1 to 2 passes with an erbium laser to diminish the residual char. This diminishes the postresurfacing inflammatory phase and lessens the associated duration of erythema.
A patient before (A) and approximately 3 weeks after undergoing carbon dioxide laser resurfacing (B). She has significant improvement in her ryhtids and some skin tightening after resurfacing. She still has residual pinkness that must be covered with makeup when she goes out.
The erbium laser is also used for resurfacing. This laser is absorbed by water and has a significantly greater coefficient of absorption than the carbon dioxide laser. This greater coefficient of absorption results in less adjacent thermal injury. This results in quicker healing and briefer postresurfacing erythema, with a tradeoff of less collagen contracture and less stimulation of neocollagen production. Furthermore, this laser is not hemostatic, so there is typically bleeding when the dermal vasculature is encountered.
To achieve greater stimulation of neocollagen production and hemostasis at the time of resurfacing, some manufacturers have modified this laser so that a longer pulse duration can be selected in addition to the usual pulse duration. These longer-pulse-duration erbium laser passes create greater adjacent thermal injury and can provide hemostasis. Furthermore, there is greater neocollagen formation than with the standard erbium laser. As might be anticipated, associated with the greater adjacent thermal injury, increased postresurfacing duration of erythema occurs.
Is a nonablative laser best for your patient’s facial rhytids? When considering this question, it is important to consider all of the underlying issues. Does the patient’s medical history or skin condition place any limitations on the options for treatment? What are the patient's goals? What specific improvement is the goal of the skin rejuvenation procedure? What is the patient truly willing to undergo to achieve these goals?
The patient’s medical history may determine which, if any, laser modality is appropriate. Some dermatologic conditions, such as psoriasis, are a contraindication. Prior radiotherapy can also result in impaired healing after resurfacing. Recent prior use of isotretinoin can result in problems with scarring. More detailed discussions of these issues can be found in published texts.25,26 Patients with darker Fitzpatrick skin sun types (V or VI)27 should not be treated with current resurfacing laser technology due to the risks of significant dyschromia and scarring.
The carbon dioxide and erbium resurfacing lasers have been used for the treatment of different skin problems, including rhytids, photoaging, actinic surface changes, and acne scars (Figure 3). When performed to an adequate depth, laser resurfacing can give noticeable, significant improvement. However, if resurfacing is carried too deep into the reticular dermis, hypertrophic scarring can result. Typically, after resurfacing a period of pinkness of the treated area occurs. This pinkness varies directly with several factors, including (1) the depth of resurfacing, (2) the depth of the associated thermal injury, and (3) the extent of the associated inflammatory response. In some patients, pinkness can persist for several weeks. There can also be transient dyschromia as part of the healing process or persistent dyschromia. Some patients can develop hypopigmentation. This is not acceptable to all patients. It is important to discuss in detail these possible outcomes with the patient before performing resurfacing.
This patient’s acne scars (A) were treated with a carbon dioxide laser, which resulted in a significant improvement (B). Reprinted with permission from Lippincott-Raven Publishers.6(p121)
These observations create a dilemma. The current technology that offers the potential for the greatest improvement also has the longest recovery time and a greater risk of complications. After discussing this with patients, we have noted that many patients do not want to deal with the prolonged recovery and risks.
As noted, current nonablative technology yields more modest improvements than laser resurfacing. Furthermore, these improvements develop slowly during the months following the procedures. The combination of modest improvements with delayed onset can result in patient dissatisfaction. Although complications are less likely with nonablative technology, it is still possible to develop scarring or dyschromia. Before performing nonablative treatments, it is important for patients to understand the limitations of the procedure. If the patient anticipates a greater result than can be achieved, the patient will not be satisfied with the result. Considering this, it is important to discuss likely outcomes in detail with the patients before performing a nonablative procedure. Patients who understand the limitations of nonablative procedures are usually pleased with the results.
Additionally, since current nonablative procedures offer modest results, combining nonablative procedures with other techniques to optimize the observable improvement is recommended. Since patients who prefer nonablative procedures generally do not want to lose time from regular activities, it is important when combining techniques to use other procedures that also do not have a significant recovery period. Frequently, it is possible to combine nonablative procedures with botulinum toxin and fillers as appropriate. Currently, 1 of us (P.J.C.) is studying whether results of nonablative laser treatments can be enhanced by using combined modalities.
When selecting the optimal technology for facial skin rejuvenation or treatment of facial scars, consider the condition to be treated and the patient's desires. An informed patient will make his or her own decision regarding the optimal technology for treatment.
Laser technology has progressed rapidly during the past several years. As new technologies become available, we will have more treatment options for our patients. It is hoped that these new treatments will be able to offer enhanced results with fewer risks and minimal recovery time.
Correspondence: Paul J. Carniol, MD, 33 Overlook Rd, Suite 202, Summit, NJ 07901.
Submitted for Publication: April 23, 2003; final revision received April 15, 2004; accepted June 16, 2004.
Financial Disclosure: None.
Carniol PJ, Greene BA. What Are the Optimal Techniques for Skin Rejuvenation? Arch Otolaryngol Head Neck Surg. 2004;130(11):1328–1333. doi:10.1001/archotol.130.11.1328
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