Acne Scars: Dermabrasion, CO2 Laser Or Combinations
Gary D. Monheit, M.D.
Associate Professor
Department of Dermatology
University of Alabama at Birmingham
Birmingham, Alabama

The modalities available for treating acne scars remain imperfect. At this time, there are no methods available that will “remove the scar” as most patients wish when they come for consultation. The realistic perspective is to blend or camouflage the scar with surgical tools available to us. Distensible, depressed scars can be elevated with subcision, collagen products, Fibrel or fat, ice-pick scars are punched out and replaced with small grafts, and stellate or jagged scars are replaced with scar revision procedures. Each of these techniques still leaves surface scar and textural change that can be seen or felt. Guttate and fibrotic scars are then resurfaced with available tools such as dermabrasion, the CO2 resurfacing laser or more recently, the Erbium Yag laser. Limitations in resurfacing techniques are determined by depth, contour, and color of the scar. Though blending is an improvement in overall appearance, any one of these procedures usually does not give a perfect result. For this reason, the author proposes a combination of procedures to solve the multiple problems of the acne scar patients.

For nearly fifty years, dermabrasion has been the premiere modality for resurfacing scars. Since Kurtin first promoted the use of a wire brush on a motorized shaft to sand the skin surface for improving skin textural abnormalities, dermabrasion has been the mainstay to plane down surface irregularities of acne scars. The addition of the diamond fraise, the use of refrigerants to firm the skin surface for more even planing, and developments in technique and anesthesia have established dermabrasion as the standard of care for treatment of acne scars and textural changes of facial skin. Over the years, though, there has only been a small core of cosmetic dermatologists and surgeons who have used dermabrasion techniques. This is because the procedure is technique-sensitive with a long learning curve. In addition, it is a major surgical procedure requiring extensive local anesthesia, or tumescent anesthesia along with sedation, and has been condemned for being a “bloody procedure”. Scarring complications have ensued when inadequately trained physicians have attempted to tackle difficult dermabrasion problems, and physicians have been overly aggressive with deeper acne scars.

Most recently, the advent of the resurfacing laser has established a new tool for treatment of photo-aging skin and acne scars. The pulsed CO2 laser vaporizes a controlled depth of skin depth to stimulate the regeneration of new skin. Like the chemical peel, the CO2 laser removes the same uniformed depth of tissue on smooth or irregular skin. Penetration of peel solution and vaporization of tissue occur at a uniform depth throughout the entire area being resurfaced, which is the ideal approach for photo-aging skin. Treatment to a depth of the upper reticular dermis will remove the zone of collagen degeneration and stimulate a new grenz zone of new collagen fibers. Using the laser, the observation was made on the operating table that there is a unique contraction of collagen that occurs as a result of dermal damage. This collagen fiber shrinkage improves the result of treatment by tightening the photo-aging skin. The zone of dermal necrosis necessary to achieve these results, though, has raised a red flag of complications which may include hypopigmentation, textural change, and scarring, similar to that seen with deep phenol peeling.

The use of the CO2 laser for acne scars must differ from those developed for resurfacing photo-aging skin. The irregular mountains and valleys on the skin surface of acne scar patients need to be sculpted or planed rather than uniformly resurfaced. The use of the diamond fraise or wire brush on refrigerated or chilled skin provides the surgeon with tools for which he can take the tops off the mountains and level the skin surface. The CO2 laser, like the chemical peel, uniformly drops the depth of injury on both elevated and depressed areas of skin. Thus, the technique of sculpting scars is more difficult with a resurfacing laser than with the dermabrader. Recently, several authors have reported the benefits of resurfacing lasers for acne scars.

The CO2 laser has made a full-face procedure easier, simpler, and faster, but the results are not as gratifying as expected with dermabrasion. Fulton has emphasized the use of multiple modalities for the treatment of acne scars and has used laser resurfacing and dermabrasion together for the treatment of acne scars. The author has followed this lead in his approach to the patient with acne scars. Combined modalities have a value that will improve the skin texture beyond each alone. For this reason, I have developed a combined technique of laser resurfacing with dermabrasion to utilize the advantages of each technique for use with dermabrasion.

Combination Dermabrasion – CO2 Resurfacing
Combining CO2 resurfacing with dermabrasion allows the surgeon to use the abrasive technique specifically over the scars, and laser resurfacing over those broad areas of skin that do not need sculpting. That is, the entire face will receive two passes of the resurfacing laser to be followed by elective dermabrasion over individual scars. Dermabrasion proceeds in the usual manner until a visual endpoint – the sebaceous lobules - is reached, or the scar is significantly improved. At that point, a last selective CO2 laser pass can be made around the shoulders of the scars to enhance the collagen contraction and further blend the depressed scar. The results with this combined technique seem to be better in some patients or comparable to that of full-face dermabrasion, and does simplify the procedure for the operating surgeon.

Method
All patients are treated prior to the procedure with cosmoceutical agents. Vitamin-A skin conditioning is begun four to eight weeks prior to the procedure. The stimulation of rapid epidermal cell proliferation and new collagen formation encourages faster and more uniform healing. All patients are given an antiviral agent, acyclovir 400 mg. b.i.d. prior to the procedure and this will be continued for ten days post-operatively. Those patients with darker skin – Fitzpatrick type III to V – are treated pre-operatively with hydroquinone 4% to 8% to prevent reactive hyperpigmentation. The bleaching product will be resumed three weeks after surgery.

The patient is prepared pre-operatively in the usual manner for full-face resurfacing or a full-face dermabrasion. The procedure is performed either under general anesthesia or sedation with local skin anesthesia. The level and extent of local anesthesia must be greater than the local nerve block that provides anesthesia for dermabrasion. The refrigerant used for dermabrasion gives added anesthesia that is not present for the resurfacing laser. The patient thus needs either full-face tumescent anesthesia, or multiple local field blocks distributed in quadrants over the facial surface. Eye shields are placed on the patient for protection, and wet drapes are placed around the operative field, preparing for laser resurfacing first. The acne scars are marked and the areas for dermabrasion outlined. Full-face resurfacing passes are first made using the standard CO2 resurfacing technique. Using the Coherent ultrapulsed laser with a computer pattern generator (CPG), the following parameters are used for the first two full face passes: 300 milli-joules, 60 watts, density of five, with a CPG pattern of 38. If the periorbital skin and eyelids are included, the parameters are reduced to 250 millijoules, 50 watts, and a density of 5. The necrotic debris is wiped with damp 4 x 4’s to clean between the passes, and after the second pass the scars become clearly visible to the surgeon.

At this point, the surgeon will switch to dermabrasion. The areas are blocked with square towel drapes, giving a 5-7 cm. area for freezing and sanding. A medium diamond fraise is used with the Bell hand engine for sanding. The skin is chilled for ten seconds with a freon 11/ethyl chloride mixture (Frigiderm). This is a less intense freeze than performed with dermabrasion alone. A denuded papillary dermis is being resurfaced. Dermabrasion is performed at lower RPM and with fewer passes because the damaged collagen can be removed easily. The irregularities in texture are then sculpted and planed. The procedure of freeze-sand is repeated until the endpoint is reached. That is the visual smoothing of the acne scars or the appearance of sebaceous lobules in the dermis. This protocol must be reduced in facials areas more susceptible to scarring such as the forehead, zygomatic arch, temple, jawline and chin where one or two cycles are sufficient. At the conclusion of the dermabrasive portion, saline compresses are placed to control hemostasis. The field is dried and the surgeon then returns to the resurfacing laser. At 250 milli-joules and 50 watts and a density of three with a single spot or linear CPG pattern, a final laser pass is made over the outer perimeter of scars. The touch-up will shrink collagen to further smooth the scar. It is at this depth the surgeon visually appreciates the mauve color-change indicating the thermal effect on the collagen.

At the conclusion of the final laser pass, the non-abraded laser treated skin and surrounding transition zones are dermasanded following the technique of David Harris, M.D.3 Silica combined with sandpaper, (150 gt), is rolled as an instrument to manually sand the transition zones such as jawline and neck, hairline, eyebrows, laser gaps and irregularities in the treated areas. A light manual sanding of the laser areas will remove the necrotic debris as done by Erbium laser – and may promote more rapid healing.
The patient is treated post-operatively in the usual manner with biologic dressings, soaks, and occlusive salves. My approach is to use a biologic dressing – Flexzan, which is changed daily for the first three to five days. At that time, the patient switches to ¼% acetic acid soaks with Vaseline petroleum jelly four times a day. The soaks and ointment create a light debride that will liquefy the crusts during the coagulation phase of wound healing, accelerating epidermal regeneration and wound healing. After 10-12 days, epithelialization is usually complete, and the patient is switched to a non-detergent cleanser, a lighter moisturizing cream, and a mild topical steroid for areas of remaining erythema. The dermabraded portions usually take a little longer to epithelialize than the resurfacing area. Healing is almost always complete within two weeks.

Conclusion
Combining laser resurfacing with dermabrasion achieves a level of improvement beyond what each of these techniques produce individually. The laser resurfacing initially brings the abrasive level of treatment to the dermis, simplifying and speeding up the procedure. The dermabrasion then corrects the scars and the final laser touch-up will shrink dermal collagen around the scars. The combination procedure will produce results beyond what each modality can achieve. The combined procedure seems especially indicated in the older patient with acne scars. This is the patient who notes the acne scars have become worse in middle age as skin laxity has increased and scarring has become more apparent. In this patient, the surgeon is treating both photo-aging skin and acne scars, and the use of both modalities seems to give a superior result to that of resurfacing or dermabrasion alone. For the younger patient with acne scars, this result can be equal to that of dermabrasion, but is usually not superior. The advantages of the combined procedure in this patient are that it simplifies the approach to the operating surgeon. Dermabrasion is a time-intensive procedure and requires the utmost concentration for control of the spinning wheel over the entire face. Limiting the dermabrasive portion to the areas of need simplifies the procedure. The surgeon must be alerted to the fact that he cannot be as aggressive with either procedure when combining the two. Dermabrading of skin that has already received two passes with the resurfacing laser must be performed much more conservatively than full-face dermabrasion de novo. Conversely, the surgeon must use his judgement in placing a last pass over the dermabrasive area. This is dependent upon depth of dermabrasion and skin type and the area treated. Over-aggressive usage of this combined approach can result in scarring, hypopigmentation, and adverse textural changes. The surgeon must temporize his zeal to eradicate the scar with the knowledge that even this approach is an imperfect procedure and cannot “remove the scar”. This combined approach, though, will produce a significant improvement in skin texture and blending of the scars.