Chemical and Mechanical Skin Resurfacing

Indications

The preoperative consultation is important in identifying at-risk patients who are best avoided or who require an extra-cautious approach, as well as in selecting patients who are ideal candidates for intervention. The dermatologist must evaluate the prospective patient and his or her skin condition carefully, in order to determine if a chemical or mechanical resurfacing procedure is indicated. When resurfacing is deemed appropriate, selection of the proper procedure for each patient is critical to assure that the desired results are achieved in a safe and effective manner. In general, the degree of skin surface irregularities is proportional to the depth of the injury that must be created by resurfacing in order to achieve significant improvement. There are six major indications for resurfacing ( Table 154.2 ).

Pre-neoplastic or neoplastic skin lesions can certainly be improved with resurfacing procedures. Those originating in the epidermis, such as actinic keratoses or lentigines, are more amenable to treatment than those with a dermal extension or origin. Although some dermatologic conditions may be aggravated by resurfacing, acne and pigmentary dyschromias such as melasma respond favorably to superficial chemical peeling or microdermabrasion, especially when accompanied by appropriate cosmeceutical products and sunscreens. Another indication for chemical and mechanical skin resurfacing is to blend the effects of other procedures by preventing or eliminating lines of demarcation.

Photoaging is probably the single condition for which skin resurfacing procedures are most often performed. For patients with photoaging, the Glogau system (see Ch. 152 ) is helpful in deciding upon the most appropriate skin rejuvenation program. It classifies patients into one of four groups based on degree of severity. Patients in category I are often young with minimal to mild photoaging and are best managed with superficial chemical peels or microdermabrasion in conjunction with topical medications or cosmeceuticals (e.g. retinoids, glycolic acids, antioxidants, vitamin C, vitamin E). Patients in category II would likely benefit from a medium-depth chemical peel as well as long-term medical therapy to include a retinoid and/or an α-hydroxy acid (AHA). Individuals in category III typically need prolonged medical treatment in conjunction with one of the following: a medium-depth chemical peel (with or without dermasanding), a deep chemical peel, dermabrasion, or laser resurfacing. For patients with category IV photoaging, interventions utilized for category III individuals are also recommended, but the addition of an invasive surgical operation such as a rhytidectomy or blepharoplasty is often required in order to achieve the desired results. Nowadays, reconstruction of facial form and correction of deep furrows with injectable neurotoxins and soft tissue fillers is such that resurfacing techniques represent a final stage in the combination approach to facial rejuvenation (see Chs 158 & 159).

Contraindications and Patient Selection

When evaluating a patient for chemical or mechanical resurfacing, a careful history and physical examination are important to assess the skin problems which prompted his or her presentation and to identify any factors that may contribute to intraoperative or postoperative difficulties ( Table 154.3 ). The patient should be asked about prior resurfacing procedures, rhytidectomy (facelift), or oral isotretinoin therapy within the last 6 months, as these can increase the risk of complications following medium-depth and deep resurfacing . Any history of abnormal scar formation or therapeutic radiation exposure warrants extreme caution when considering a patient for skin resurfacing. Individuals with prior radiation exposure should be examined closely for the presence of intact facial hair in order to ensure that there are enough pilosebaceous units to promote re-epithelialization . Another important element of the patient's history is the presence or absence of a prior herpes simplex viral (HSV) infection. Recurrence of oral HSV can be triggered by a resurfacing procedure, especially in the perioral and periorbital regions. Risk factors for HIV infection or viral hepatitis should be identified, and routine laboratory screening is recommended in individuals undergoing dermabrasion with a powered engine. A history of abnormal wound healing from trauma or previous procedures, e.g. hypertrophic scarring, dyschromia, may be a contraindication to peeling or dermabrasion. The general health and nutritional status of the patient is also an important consideration, especially for medium-depth and deep resurfacing procedures, to ensure timely and complete healing.

Patients with certain cutaneous disorders, such as rosacea, seborrheic dermatitis, atopic dermatitis, psoriasis or vitiligo, may be at increased risk for postoperative complications, including disease exacerbation, prolonged erythema, contact dermatitis, or even delayed healing. In particular, individuals with rosacea have vasomotor instability and may develop an exaggerated inflammatory response to the resurfacing procedure. Caution should also be exercised for patients with autoimmune connective tissue diseases (e.g. cutaneous lupus, systemic sclerosis) as the trauma of chemical peeling may exacerbate the disease. Evaluation of the patient's Fitzpatrick skin type (see Ch. 0 ) is helpful in predicting the chance of postoperative pigmentary dyschromias. Individuals with Fitzpatrick skin types I or II are at low risk for hyperpigmentation or hypopigmentation after medium-depth or deep resurfacing, whereas those with types III through VI are at greater risk for these complications .

The patient should understand that chemical and mechanical resurfacing procedures cannot reliably reduce pore size, and their ability to improve lax skin or deeper wrinkles and scars is limited and depends upon the type of intervention being performed. While dermabrasion may sometimes eliminate telangiectasias, chemical peels cannot accomplish this and can even unmask them by removing the pigmentary irregularities. The patient must fully understand the potential benefits, limitations and risks of the procedure, and an informed consent must be signed.

A test spot (e.g. along the lateral hair line) may be useful in some patients to assess their suitability for resurfacing and may be particularly helpful when there is a great deal of concern about the chances of postoperative pigmentary dyschromias ; test spots are definitely recommended for individuals with skin types III–VI. Of note, while a favorable test spot result does not guarantee a positive outcome following full-face resurfacing, an unfavorable test spot result is useful in identifying high-risk patients. The latter include those at risk for postinflammatory hyperpigmentation, spotting, irregular coloration, or hypopigmentation. If the dermatologist feels any uncertainty about the patient's suitability or the likelihood of a favorable result, the procedure should not be performed.

Preoperative and Intraoperative Preparations

Another purpose of the preoperative consultation is to ensure that the patient is adequately prepared for the procedure. Almost every patient desiring facial rejuvenation for cutaneous photoaging would benefit from botulinum toxin injections to alleviate dynamic wrinkles (see Ch. 159 ). These injections appear to enhance the results of deeper resurfacing procedures by immobilizing the muscles implicated in the development of dynamic rhytides during the critical time of postoperative collagen remodeling. In patients with photoaging, it is recommended that botulinum toxin injections be administered as an adjunctive therapy at least 3 days prior to medium-depth or deep chemical peels, dermabrasion, or laser resurfacing.

Due to the significant morbidity associated with herpetic infections during the healing period, patients who undergo medium-depth or deep resurfacing (see Table 154.1 ) should be treated prophylactically with an antiviral agent, regardless of whether there is a history of HSV infections . These drugs are not routinely given to patients having a superficial chemical peel or microdermabrasion, because the injury is generally not sufficient to activate the virus. However, therapy may be considered in conjunction with superficial resurfacing in patients with a strong personal history of recurrent HSV infection. Recommended prophylaxis consists of acyclovir 400 mg three times daily, valacyclovir 500 mg twice daily or famciclovir 250 mg twice daily, beginning on the day of the procedure. It is advisable to administer the drug for at least 10 to 14 days thereafter . The reason for such a long duration of therapy is that viral replication is possible only in intact epidermal cells, making clinical infection unlikely during the first few days postoperatively. The risk of an eruption increases dramatically with the onset of re-epithelialization and remains high until this process is complete.

It is important that the patient adhere to a strict skin care regimen during the immediate preoperative and postoperative periods in order to achieve optimal results. The authors treat patients with topical tretinoin on a nightly basis prior to the procedure. Retinoids increase epidermal proliferation and presumably lead to more rapid re-epithelialization after the chemical peel. Because of the tendency for retinoids to cause irritation within 1 to 2 weeks of starting therapy (i.e. retinoid dermatitis), a weaker, more gentle tretinoin formulation should be used in patients with sensitive skin. In patients with active retinoid dermatitis, resurfacing should be delayed, because this condition may lead to a prolongation in postoperative erythema. Decreasing the frequency of application or switching to a less irritating retinoid will allow the inflammation to subside, so that the procedure can be performed .

All- trans -retinoic acid, or tretinoin, has been classified as a superficial chemical peeling agent, but it is best considered as an integral component of a complete skin rejuvenation program. With chronic use, this drug has been shown to improve actinically damaged skin both clinically and histologically . The use of tretinoin prior to chemical peeling, dermabrasion or laser resurfacing speeds epidermal healing and enhances the effects of the procedure . For chemical peels in particular, use of preoperative topical tretinoin to reduce areas of hyperkeratosis and decrease the thickness of the stratum corneum allows for greater penetration of the peel solution, resulting in a more homogeneous peel and a deeper peel. Use of tretinoin is restricted, however, during the postoperative healing period, until there is complete re-epithelialization and diminished inflammatory erythema.

Hydroquinone blocks the enzyme tyrosinase and can reduce the production of epidermal melanin during the healing phase. Patients with skin type III or higher may benefit from twice-daily application of 2% to 4% topical hydroquinone during the preoperative and postoperative (post-healing) periods – even if there is no history of pigmentary abnormalities . It is also necessary to use hydroquinone in patients of any skin type when peeling is done to treat pigmentary dyschromias such as melasma or postinflammatory hyperpigmentation . While a Wood's lamp was used in the past to localize melanin pigment to either the epidermis or dermis (i.e. epidermal versus dermal melasma), histopathologic studies and confocal microscopy have shown that there is often a mixture of the two forms in an individual patient. Nonetheless, in both melasma and postinflammatory hyperpigmentation, increased melanin within the epidermis responds better to superficial peels than does dermal pigment. The use of non-inflammatory peeling agents, e.g. salicylic acid, is preferred for disorders such as melasma as there is less tendency for postinflammatory hyperpigmentation ( Fig. 154.1 ).

All patients undergoing any type of skin resurfacing procedure must adhere to strict photoprotective measures during the postoperative period. This issue is critical in patients whose Fitzpatrick skin type is III or higher, in patients with pigmentary abnormalities, in patients taking exogenous estrogens, and in all patients having medium-depth or deep resurfacing. Specific methods to minimize sun exposure and proper use of sun blocks should be discussed. Patients are also counseled to avoid tobacco use, as smoking in the postoperative period may interfere with the healing process, thereby limiting the effectiveness of the resurfacing and increasing the risk of poor wound healing.

The need for intraoperative sedation and analgesia is also discussed with the patient preoperatively, so that plans are made accordingly. Superficial resurfacing procedures usually require only “talkesthesia”, a technique that is extremely helpful in awake patients undergoing a procedure, i.e. talking calmly to the patient with encouragement during the procedure. Medium-depth chemical or mechanical resurfacing usually requires a limited degree of perioperative sedation and analgesia, which may include the application of topical amide anesthetics and regional blocks of the supraorbital, infraorbital and mental nerves (see Ch. 143 ), as well as oral diazepam, intramuscular meperidine hydrochloride, and/or intramuscular hydroxyzine hydrochloride. Although deep resurfacing procedures can be accomplished entirely with nerve blockade, local injections of lidocaine, and mild sedatives, some patients require intravenous or general (endotracheal tube) anesthesia. Application of the tumescent technique (see Ch. 156 ) to resurfacing has allowed many patients to undergo deep resurfacing procedures without the additional risks of intravenous or general anesthesia . The patient's inherent pain tolerance, level of anxiety, concomitant medical conditions, and willingness to pay the extra costs of heavier sedation are important topics to discuss during the preoperative consultation that is used to plan for appropriate anesthesia.

Preoperatively, the patient must be given specific instructions to follow, both for the day of the procedure and for postoperative care. These should be carefully reviewed verbally prior to the procedure, with the same instructions provided in written form. On the day of the procedure, the patient washes his or her face with a gentle cleanser and preferably avoids the application of any cosmetics. Individuals undergoing procedures requiring minimal or no sedation are encouraged to eat a light breakfast, but patients receiving deeper anesthesia should have nothing by mouth except for their usual medications. Particularly for the medium-depth and deep resurfacing procedures, the dermatologist should meet with the patient and his or her family preoperatively to re-establish rapport, answer last-minute questions, discuss perioperative and postoperative expectations and instructions, and assure compliance with antiviral prophylaxis as needed.