Posted 22 February 2004 - 03:40 PM
Here's a pretty good article.
It doesn't show the pictures though. If you register you can see it. It's free.
Article as Full-Text Content Catalog Help
Facial Plastic Surgery
Facial Plast Surg 2001; 253-262
Scar Revision Via Resurfacing
Dewayne T. Bradley M.D. , Stephen S. Park M.D. FACS
Department of Otolaryngology/Head and Neck Surgery, Division of Facial Plastic Surgery, University of Virginia, Charlottesville, VA
Numerous techniques exist to treat noticeable facial scars. Techniques range from surgical excision to resurfacing. In this review of dermabrasion and laser resurfacing, we address the clinical considerations, techniques, adjuncts, and peri-operative management of scar resurfacing. Dermabrasion offers the advantage of being a tried-and-true technique familiar to surgeons. Recent advances in laser technology have resulted in the increased use of pulsed-dye lasers (PDLs), erbium:yttrium-aluminum-garnet (YAG) lasers, and CO2 lasers. PDLs are effective for hypertrophic scars and show lower rates of recurrence compared with erbium:YAG and CO2 lasers. In contrast, erbium:YAG and CO2 lasers are well suited to treating atrophic and acne scars. Chemical peels play a minor role in scar resurfacing and function primarily as an adjunct. Scar resurfacing is an integral part of scar camouflage and is often used in conjunction with excision and irregularization techniques.
Dermabrasion - laser - scar - resurfacing
Numerous techniques have evolved in facial plastic surgery to camouflage noticeable scars. Techniques range from surgical excision to resurfacing. Often optimal results are only achieved by combined modalities, and resurfacing can play a primary role or serve as an adjunct to surgery. It is important to point out that scarring is the natural healing response to cutaneous injury. The goal is to hide scars and make them as inconspicuous as possible because they can never be completely eliminated. Dermabrasion is a tried-and-true technique that has produced good results. In addition, advancements in laser technology have provided several new tools for scar revision. This review addresses the clinical considerations, techniques, and peri-operative management of scar resurfacing.
TIMING OF REVISION
The initial scar after cutaneous injury can be expected to change over time due to collagen remodeling and collagen fiber reorientation. Although the amount of collagen and number of fibroblasts change for approximately 1 to 3 years, most significant changes occur in the first 6 months, and a 6- to 12-month delay before revision is prudent. In clinical situations where skin edges are grossly misaligned or the scar is unfavorably oriented, scar revision may be beneficial as early as 2 months.
Clinical circumstances that may warrant resurfacing include acne scars, hypertrophic scars, atrophic scars, traumatic scars, surgical scars, traumatic tattoos, superficial tattoos, superficial pigmented lesions, and keloids. Due to the prevalence of acne and subsequent scarring, acne scars represent a frequent indication for resurfacing.
Resurfacing can cause a reactivation of facial herpes, even in untreated areas. Generally, herpes should be dormant for 4 to 6 months and the patient should avoid contact with others who have active infection. Treatment with perioperative antivirals to reduce the risk of reactivation in individuals with a history of facial herpes is indicated. The most common regimen is a 10-day course of acyclovir (Zovirax, Glaxo Wellcome, Research Triangle Park, NC) starting the day before the procedure. An alternative regimen of valacyclovir (Glaxo Wellcome, Research Triangle Park, NC) 500 mg po bid for 14 days has proved highly effective with 100% reactivation prevention and the convenience of bid dosing. No difference was found starting valacyclovir the day of or the day before dermabrasion.
Recent use of 13-cis-retinoic acid (Accutane/ isotretinoin, Roche Laboratories, Nutely, NJ) should be noted. Although evidence has been largely anecdotal, postresurfacing hypertrophic scarring has been reported. This medication is largely used for medical management of acne vulgaris by a mechanism of suppressing the pilosebaceous units. Because these adenexal structures are pivotal for epidermal regeneration following resurfacing, the patient should be off retinoic acid therapy for a minimum of 9 to 12 months.
Radiodermatitis also decreases the number of pilosebaceous units and places the patient at increased risk for scarring. Because the effect of radiation will be long lived, a conservative dermabrasion can decrease the risk of scarring.
Collagen Vascular Diseases
Collagen vascular diseases may place the patient at risk for a suboptimal result due to scarring and persistent erythema. In addition, patients with collagen vascular disease frequently have skin appendage atrophy and may have trouble with scarring for the reasons cited for retinoic acid. Asking all patients about cold intolerance, which may signify a collagen vascular disease such as Raynaud's, is reasonable.
A previous chemical peel has multiple cutaneous effects including decreased skin vascularity and flattening of the dermal-epidermal interface; the clinician should use a light touch during abrasion to prevent scarring.
In general, dark-skinned patients respond well to dermabrasion but must be counseled regarding the risk of dramatic postoperative hypopigmentation. Hypopigmentation usually resolves after 6 weeks, but permanent vitiligo can result.
An assessment of the patient's goals, concerns, and expectations cannot be overemphasized. By clearly explaining what can and cannot be achieved by resurfacing, unrealistic expectations can be decreased and postprocedure dissatisfaction minimized. Many patients expect scar disappearance and thus even a significant amount of scar camouflage may be perceived as a failure.
Several reports have been published suggesting that treatment of skin with topical tretinoin (Retin-A, Ortho Biotech, Inc., Raritan, NJ) may increase the rate of reepithelialization by stimulating sebaceous gland activity and the pilosebaceous unit. Although its use is theoretically sound, the studies suggesting improved postoperative healing have been uncontrolled, and routine use is not universal.
A history of abnormal clotting or significant hemorrhage should prompt further investigation. The investigation may warrant laboratory testing such as complete blood count, coagulation studies, and a bleeding time. Any use of antiplatelet and anticoagulant medication should be discontinued for at least 7 days.
Dermabrasion is generally performed on an outpatient basis. The use of brief intravenous sedation combined with nerve blocks is useful for extensive resurfacing. Because infiltration of anesthetic in the area of resurfacing distorts the contours, selective injections of the supraorbital, supratrochlear, zygomaticotemporal, zygomaticofacial, infraorbital, infratrochlear, and mental nerve branches provide excellent anesthesia with minimal distortion (Fig. ). For more superficial work application of EMLA cream (lidocaine/prilocaine cream, Astra Zeneca LP, Wilmington, DE) provides adequate anesthesia.
Skin refrigerants have been used to freeze the skin, providing a stable platform on which to dermabrade. The freezing allows depressions to be fixed, resulting in a more consistent depth of dermabrasion. Ethyl chloride was used initially but abandoned due to safety concerns. Freon-based refrigerants, such as Frigiderm (Frigiderm-Brachvogel, Costa Mesa, CA), were widely used but subsequently pulled from the market due to concerns of ozone destruction. Most recently, solid carbon dioxide has been used as a means of providing anesthesia and facilitating scar sculpting. Generally, skin refrigeration is not uniformly practiced.
A number of dermabraders exist and consist of a powered hand unit and attachments called fraises that do the abrading. The hand pieces fall into either the motor- or gas-driven variety. Depending on the model, the hand units can rotate up to 50,000 rpm's. The fraises are either wire brushes or wheels with diamonds bonded to the surface (Fig. ). The fraises come in a variety of shapes and sizes that can accommodate most scar and anatomic configurations. Generally the brush fraises are run at low speed to maintain control without gouging and diamond fraises are used at higher speeds. A protective guard can be attached and is helpful to deflect the spray of blood and debris. Protective gear, including a gown, goggles, gloves, and mask or face shield, is essential. The use of towels rather than gauze sponges is important as sponges are easily caught in the fraises, especially the wire brush type. Assistants must be instructed to resist the urge to remove debris during the procedure with gauze sponges.
After appropriate sedation and anesthesia, the area is painted with 1% gentian violet. The gentian violet serves as an antiseptic and colors the area to be treated. Specifically it is used in depressed scars and acne scars to provide a useful guide to scar depth. Alternatively the area may be marked with an ink-marking pen.
Multiple dermabrasion techniques have been suggested. The dermabrader is held like a pencil and oriented at a 45-degree angle to the axis of the scar. After the first pass over the scar, the dermabrader is oriented at a 90-degree angle to the initial sanding orientation. Additionally, moving the dermabrader perpendicular to fraise rotation has been advocated by some to prevent loss of control and gouging. Starting in dependent areas helps keep the future operative site clean and can therefore save significant time.
Attention to the direction of fraise rotation is also important. Diamond fraises can be rotated in a clockwise or counterclockwise direction while wire brushes should only be rotated in the clockwise direction. If the fraise is run in the clockwise direction and the operator moves the fraise from left to right, then a clean operative site will be encountered as debris will be deposited behind the path of abrasion. When abrading near mobile structures such as the lip, ala, or eyelid, the direction of rotation should be toward the mobile structures to avoid retraction.
To determine the end point of dermabrasion, one can simply abrade conservatively until a suitable contour is achieved. Alternatively abrasion may progress until all the gentian violet or ink marking is removed, indicating complete deepithelialization of the recessed scar. Finally, the end point can be determined based on the appearance of the skin. As deepithelialization progresses, the appearance of pinpoint bleeding is encountered, which indicates the invasion of the dermal papillae with its capillary plexus. Continued abrasion reveals parallel lines corresponding to the superficial reticular dermis, followed by the appearance of frayed white strands indicating the reticular dermis (Fig. ). This should be considered the end point as further dermal invasion can lead to scarring.
To achieve uniform abrasion, the skin should be stretched to stabilize it and prevent skipping. If spot sanding of a scar is performed, the abraded area should overlap the unscarred area by 1 to 2 cm to provide a smooth transition (Fig. ). Alternatively, the area of abrasion can include an entire cosmetic unit and be feathered as a natural transition into adjacent aesthetic units. For example, abrasion of the forehead should be carried from the hairline into the brow, the chin and cheeks should be abraded to under the jaw line, and the perioral area should be abraded into the vermilion border.
Several areas of the face have been referred to as danger zones: the mandibular ramus, zygomatic arch, malar eminence, chin, and bony prominence of the forehead. Bony prominences, common to these areas, increase the efficiency of abrasion and risk an overly aggressive skin removal with subsequent scarring. One must also resist the temptation of abrading areas with thin skin or fewer pilosebaceous units, such as the neck, due to the unpredictability of deepithelialization in such regions.
Wire brush fraises are particularly useful for acne scars because they create small lacerations that can be crossed to create a microscopic z-plasty effect. By moving the brush fraises at oblique angles the microscopic lacerations cause opposing vectors of contracture that act to flatten acne scars.
Several adjuncts are useful in approaching hypertrophic, atrophic, and deep ice pick scars that are not readily amenable to resurfacing. Ice pick scars are initially excised with a 2-mm punch and closed with 6-0 fast-absorbing gut (Ethicon, Sommerville, NJ) to convert a deep circular scar to a linear scar (Fig. ). The resultant linear scar may then be dermabraded. Prior to dermabrasion, both hypertrophic and broad depressed scars can be managed by shave excision. Shave excision is performed with a straight razor blade that is grasped and bent slightly between the thumb and index finger. Depressed scars often have well-defined shoulders around the perimeter that create small shadows and draw attention to them. Shaving the edge off these shoulders can smooth the transition and greatly improve scar camouflage (Fig. ).
Postoperatively, the area is covered with antibiotic ointment and a nonadherent dressing is applied. Choices of dressing include Vigilon (Bard, Inc., Murray Hill, NJ) and Telfa (Kendall Co., Mansfield, MA). Vigilon is applied by placing Mastisol liquid adhesive (Ferndale, Ferndale, MI) around the unabraded areas to hold the sheet in place. Care is taken to avoid contact of the Mastisol with the raw surface. The Vigilon usually remains in place for 5 to 7 days but, if it inadvertently comes off, we recommend covering the wound with antibiotic ointment rather than reapplication. Another method often used is frequent application of antibiotic ointment and gentle washing. An alternate option is frozen human epidermal keratinocytes as a biologic dressing, felt by some to promote rapid reepithelialization. Soap and water are used to clean the area gently, and the patient is instructed to avoid hydrogen peroxide or astringents on the area. A warm water soaked cloth can be applied to the face to soften crusts. Reepithelialization generally occurs after 7 to 10 days. Sun exposure must be avoided for at least 1 month and sunscreen (SPF 30 or greater) is used diligently thereafter. Prophylactic oral antibiotics may rarely be given for a few days to decrease the risk of wound infection. Topical steroids or prednisone can be helpful to decrease inflammation and postoperative hypertrophic scarring.
The procedure is usually performed as an outpatient with several choices of anesthesia. Frequently, for pulsed-dye laser (PDL) resurfacing no anesthesia is required. Topical anesthesia such as lidocaine-based ointments or intralesional local anesthetic can be used when necessary. If an ointment is used it should be completely removed with soap and water prior to therapy with care to avoid the use of flammable liquids such as alcohol. In contrast, CO2 and erbium: yttrium-aluminum-garnet (YAG) lasers require some sedation along with some supplemental local anesthesia. As with dermabrasion, nerve blocks provide excellent anesthesia with minimal distortion.
Basic Laser Concepts
The word laser stands for light amplification stimulated emission of radiation. A laser beam is a beam of photons whose wavelength depends on the base substance (e.g., CO2, neomydium:YAG) used for the laser. Electrons of the base substance are excited by a current. When the excited electrons decay to their resting energy level, photons are emitted. This occurs within a chamber called a resonator. Photons that exit the resonator form a uniform beam that is coherent (of the same wavelength) and collimated (beams are parallel). When the beam hits its target the light can be reflected, refracted, transmitted, scattered, or absorbed. The clinical effect depends primarily on absorption. Cutaneous absorption depends on compounds that absorb light called chromophores. Melanin, hemoglobin, and water are the three most prevalent chromophores in skin. When a laser is applied to the skin, light is absorbed by the chromophore, raising the chromophore temperature. Thus the main effect of the laser is to heat the target tissue. Pulsing the laser can limit the amount of thermal diffusion by decreasing the pulse duration to less than the target tissue thermal relaxation time. The result is less surrounding tissue damage.
The three most important lasers for resurfacing are YAG lasers, CO2 lasers, and PDL lasers. PDL lasers are often referred to as vascular lasers because they have hemoglobin as the chromophore and thus penetrate the epidermis without deepithelialization. They effect scars by making them more flexible and decreasing their size. The postulated mechanisms include collagen disulfide bond breakage, collagen fiber reorientation, and tissue hypoxia leading to cytokine-mediated remodeling. In contrast, CO2 and erbium:YAG lasers ablate superficial tissues and cause deepithelialization with water as the target chromophore.
CO2 lasers, YAG lasers, and 585-nm PDLs have all been used for scar resurfacing. In general the PDL lasers are best suited for hypertrophic scars and have shown the lowest rate of scar recurrence. Newer-pulsed CO2 lasers have been applied to atrophic scar resurfacing with good results. Currently, the use of PDL for hypertrophic scars and pulsed CO2 and erbium:YAG lasers for atrophic scars is most common.
Certain precautions are necessary when working with lasers, such as using protective eyewear and covering adjacent areas with moistened gauze to prevent burning.
The treatment of hypertrophic scars with a 585-nm PDL involves the use of nonoverlapping areas that cover the entire scar. The scar characteristics of color and thickness help guide the clinician's selection of energy density. Typical energy densities include 4.5 to 5.5 j/cm2 and spot size of 10 mm, 6.0 to 7.0 j/cm2 and spot size of 7 mm, and 6.5 to 7.5 j/cm2 and 5-mm spot size. Multiple treatments are often required. If vesiculation or crusting develops, a lower-energy setting should be selected, and care should be taken not to overlap pulse fields. If improvement is seen after the first session and no vesiculation is noted, an increase in the power settings by 10% is reasonable. Most lesions show an 80% improvement after two sessions. A period of 6 to 8 weeks between treatments is recommended to allow healing.
Atrophic scars are best treated by CO2 lasers, erbium:YAG lasers, or both. These lasers have water as the main chromophore and use high-peak powers and short-pulse duration to optimize vaporization of targeted tissue with minimal surrounding damage. These lasers deepithelialize similar to dermabrasion, and two or three passes per session are generally necessary. The entire facial cosmetic unit is usually treated to avoid unsightly transitions. The initial pass is made over the entire cosmetic unit with a CO2 laser, and subsequent passes are made with an erbium:YAG laser. In between passes, debris is removed with saline-soaked gauzes. Depending on the scar, spot vaporization can be performed on the edges to help sculpt them and reduce the shadows created by the scar shoulders. Typical settings involve use of a computer-generated pattern at 300-mj energy and a 60-watt power setting. Rates of healing and cosmetic results are equivalent between high-energy pulsed CO2 laser and dermabrasion, as demonstrated by Nehal et al.
Postoperative care depends on the laser selected. When CO2 and erbium:YAG lasers are used the care is similar to that described for dermabrasion. Dressings include occlusive, semiocclusive, and open types. Each dressing type has proponents, but we use ointment generously applied until the site is reepithelialized, typically 7 to 14 days. Continued moisturizing and sunscreen is advised for a couple of months, particularly until all erythema (CO2) or purpura (PDL) has resolved.
In general, peels have a minor role in resurfacing scars. They maybe useful for superficial acne scars or as an adjunct to other scar revision techniques, particularly when combined with other modalities. Advantages include increasing firmness and coagulating superficial blood vessels. Deeper peel agents such as pure (88%) phenol or ``Baker-Gordon'' solution are recommended, and postoperative care is similar to laser-resurfaced areas.
After dermabrasion it is possible to get a reactive hyperpigmentation adjacent to the abraded regions; the contrast in color is more commonly due to depigmentation of the abraded area, illustrating the importance of blending abraded areas. This contrast in color is especially common in darker-skinned patients and around the eye as the periorbital skin tends to be naturally darker. The hyperpigmentation usually resolves over 3 to 6 months. Hyperpigmentation can also be exacerbated by postresurfacing sun exposure. Initial sun avoidance with subsequent sunscreen use is important. It is postulated that estrogens may stimulate melanogenesis and use of oral contraceptives may place the patient at higher risk. Finally, a chemical peel can be useful to blend discrepant areas.
After laser resurfacing, hypopigmentation is seen in the first 1 to 2 months and is more apparent in darker-skinned patients. Treatment with bleaching creams such as hydroquinone applied to darker surrounding area can blend them with the hypopigmented region. Hypopigmentation can also occur after dermabrasion and usually resolves over 6 to 10 weeks. In contrast, laser resurfacing may lead to hypopigmentation that is seen later, at about 6 to 12 months, and is typically permanent.
The deepithelialized area is at risk for infection by both bacteria and fungi. Bacterial infections tend to be due to Staphylococcus, Streptococcus, or Pseudomonas and are usually treated effectively with surface cleansing and appropriate systemic antibiotics. Bacterial infections typically present on postoperative days 2 to 5 as discolored crust, malodorous discharge, or purulent transudate. Superficial treatment, in addition to routine cleansing, includes application of dilute ascetic acid or silver sulfadiazine cream. Fungal infections are generally due to candidal species and can present as pustules or superficial erythematous erosions. Treatment with oral fluconazole (Pfizer, Inc., New York) 200 mg po qd along with 0.25% ascetic acid-soaked gauze four times a day is effective.
Patients with a history of facial herpes should be treated prophylactically with antivirals. Those who develop a herpetic infection postoperatively should be immediately started on antivirals to shorten the course and minimize the risk of scarring. Patients should avoid individuals with active infections until the resurfaced scar has completely healed. Both valacyclovir and acyclovir are effective. If patients breakthrough despite antivirals, hospitalization with intravenous antivirals may be needed.
This is a very common condition that results from small inclusions of epidermis that are trapped during reepithelialization. They may be treated with excision, pinpoint electrocautery ablation, or gentle abrasion.
Delayed Healing and Scarring
Delayed healing implies a time greater than 14 days for reepithelialization. The treatment is based on the cause, which may be related to infection, patient comorbidity such as diabetes, or poor wound care. The primary treatment is thus reversal of the underlying cause. Additionally, topical tretinoin has been shown to increase the rate of reepithelialization. Delayed healing is particularly common in patients with a history of an autoimmune disorder or previous radiation treatment.
Scarring after resurfacing is generally hypertrophic in nature and results from wounding the skin too deeply. This may be due to overly aggressive abrasion in the danger zones over bony prominences or on the neck with its thin skin. Even when the initial depth is appropriate, postoperative wound care problems can lead to infection and subsequent extension of the dermal wound. The result is an increased chance for scarring, the first-line treatment of which is steroid injections.
This sequela is common to all forms of resurfacing and can last for weeks to months. Generally the erythema decreases with time and ultimately disappears. The use of steroids topically or systemically improves this condition. An erythematous base with small pustules can also develop as a reaction to neomycin-containing antibiotic ointments used for postoperative wound care. The neomycin-containing ointment should be stopped immediately and the area subsequently treated with a steroid cream, Bactroban antibacterial ointment (Mupirocin, SK Beecham Pharmaceuticals, Pittsburgh, PA), or plain petrolatum ointment.
Bleeding during resurfacing general stops without specific intervention, and postoperative bleeding is rarely a problem.
Dermatitis can occur in approximately 10% of patients and is treated effectively with topical and, rarely, systemic or intralesional steroids.
Resurfacing is a useful technique by itself and as an adjunct to other techniques in treating scars. Advances in laser technology have generated enthusiasm for laser resurfacing over the past few years, but dermabrasion still plays an important role in the management of facial scars. In this review we have addressed the clinical considerations, techniques, and peri-operative management of scar resurfacing.
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