A comparative study of skin resurfacing using a fractional Er: YAG laser versus medium-depth peeling in the management of post-acne sequelae Fractional Er:YAG versus medium-depth peeling in post-acne sequel

A comparative study of skin resurfacing using a fractional Er: YAG laser versus medium-depth peeling in the management of post-acne sequelae

Fractional Er:YAG versus medium-depth peeling in post-acne sequel

Nahed Samir Boughdadi,MD; Basim M Zaki,MD; AbdelAziz Hanafy,MD Department of Plastic and Reconstructive Surgery, Ain Shams University, Cairo, Egypt.

Co"espondence:  Nahed Samir Bougdadi, MD

11 El Adeeb Ali Adham, Heliopolis, Cairo, Egypt. e-mail: dr_nahed_samir@hotmail.com

Abstract

Background: Post-acne scarring is a common permanent disfigurement to the face and

various treatment modalities are available. Chemical peeling and ablative lasers have been used with varying degrees of success and complications.

Objective:In this study we compared the effects of medium-depth chemical peel by sequential use of glycolic acid (GA) and trichloroacetic acid (TCA), with a combination treatment of fractional and conventional Er:YAG lasers.

Methods: one hundred and twenty patients with post-acne scarring were randomly divided over two equally-sized groups. Group I underwent medium-depth chemical peeling and group II was treated with fractional Er:YAG laser. Patients were evaluated both subjectively and objectively during each follow-up visit.

Results: Laser therapy was more effective than medium-depth peel. Subjective evaluation showed a higher satisfaction rate of 87.5% in group IL satisfaction fell to 52.5% in group I. Objective evaluation showed "very good"to "excellent" outcome in 82.5% of cases treated in group  II.  In group  I outcome  was  "good" in  47.5%  and  "poor" in  32.5%  of cases.

Conclusion: Combined Er:YAG laser therapy had a shorter downtime, was more effective, showed a longer lasting effect and proved safer than the combined use of GAITCA chemical peels.

Key words: Post-acne scarring, chemical peeling, Er:YAG lasers, fractional laser treatments.

Introduction:

Over the past several years, many patients have become increasingly concerned about the cosmetic appearance of their skin; especially in the face. One of the most frequent cosmetic problems is acne vulgaris (AV), of which the most common sequelae are hyperpigmentation and scarring.l-3

Post-acne scars and hyper-pigmentation are very difficult to treat and various modalities for the elimination or improvement of already manifested acne scarring are in common use. A common treatment modality  is chemical

peeling.4 There are many products currently available for chemical resurfacing of the skin, from over-the-counter superficial peeling agents to deep-peeling chemicals. The therapeutic effect of glycolic acid (GA) in acne is claimed to be through mild  epidermolysis with dislodgment  of comedones and unroofmg of pustules that affect the follicular epithelium at the  sebaceous gland  level. Hence, excess keratinization of the pilosebaceous duct  is avoided.5,6

Medium-depth chemical peeling is defmed as controlled damage to the papillary dermis.

Indications for medium-depth peel include destruction  of epidermal lesions, resurfacing moderately photoaged skin,  correction of dyschromias, and repair  of acne scars. The classic agent for medium depth peeling is Trichloroacetic acid.  TCA emerged as the leading chemical peeling agent because of the ability it offers to specifically design the depth of acid penetration according to the nature and type of problem of the skin.7 TCA is a peeling agent  that   promotes important proteic coagulation when in contact  with the skin. Classically, TCA is used in concentrations between 15% and 50% for chemical peelings on the face.Inits liquid form and concentration of  30%, TCA  can  provoke necrosis (coagulation)  of the epidermis and, papillary and/or reticular dermis, consequently causing deep epidermolysis with a residual process that can last between three to eight weeks. Undesirable side  effects are  frequent and include post-inflammatory hyperpigmentation, hypopigmentation, infections and hypertrophic scars.8,9

Laser  resurfacing is another  modality to treat acne scarring.Both C02 (10,600 nm) and Er:YAG (2,940 nm) lasers are used for skin resurfacing.lO Er:YAG laser causes less thennal damage but more intra-operative bleeding than C02 laser. Post-operatively however, epithelialization is rapid, erythema  resolves significantly faster and the incidence of scarring is low.ll The indications for use of the Er:YAG laser are continuously expanding by the recent introduction of the fractional technique, which is considered less aggressive than the more conventional ablative mode.12

Inthis study we discuss our experience and

our  own  protocol for  post-acne facial resurfacing with the fractional Er:YAG laser, comparing the results with those of medium­ depth chemical peeling.

Patients and methods:

The study  was conducted at Ain Shams University and included 120 patients with complaints from post-acne scarring.  Eighty patients were female,  forty  male  and ages ranged between 25 and 45 years old. Patients were randomly divided into two groups. Group

I included 60 patients treated with five to ten

treatment sessions of medium-depth  peeling. Group IIincluded 60 patients treated with four to eight fractional Er:YAG  laser  treatment sessions. Both  treatment modalities were applied at  two  to  three  weeks intervals. Informed consent, which explained the purpose, possible outcome and side effects of the study, as well as permission  to document the study with medical digital photography were taken from each patient. Patients who had previous skin or eye viral herpes zoster or simplex and psychologically imbalanced patients were excluded. Oral  isotretionoins  intake was stopped for at least 6 month before the start of the treatment. Patients included in this study suffered from post-acne manifestations in the form of superficial elastolysis, pits, hyperpigmentation, atrophic scars, inflammatory scars, hypertrophic scars and keloids. These deformities were evaluated in respect to their severity using a 4-point rating scale: 1=minimal, 2=mild, 3=moderate,

4=severe. The severity of post-acne sequelae among the population of each group is recorded in Table(l).

Table (1): The severity of post-acne sequelae in both study groups, assessed using a 4-point rating scale.

Most of the patients were  of Fitzpatrick skin types II-IV (95%), and only 5% were of type V. The relative  representation of each

Table (2): Skin types in each group.

skin type among the population of each group is shown in Table(2).

Patients were  prepared for  a two-week period prior to the treatments using  4% alpha hydroxyl-acid skin cream, and sunscreen with sun protection  factor 100. Chemical peeling sessions started by cleansing  the face with a normal 0.9%  saline solution. GA at  70% concentration was applied for  one  minute followed by complete removal. TCA, at 15% solution,  was then applied  until white frost was achieved. A sterile cotton pad is used for application and removal in the same way and direction as application. Post-peeling management included applying topical soothing cream, sunscreen  and avoiding  make up for three  to five  days  after  the treatment. Pre­ operative preparations for the next session were  then  commenced and  sessions were repeated at 2-3 weeks  interval. Number  of sessions ranged from 5-10.

The  fractional 2940  nm,  Er:YAG  laser treatment was administered using an XS Dualis laser  system  (Fotona, Slovenia), which  is capable of  providing fractional ablative,

fractional non-ablative and conventional full­ field ablative Er:YAG modalities. Fractional treatments are based on variable square pulse

{VSP)  and  pixel  screen technologies; the fractioned laser beam's pulse durations ranges from 100 1.1 s for very short pulse (VSP) mode to 1.500 J.L  s for extra long pulse (XLP) mode. Combinations of different pulse  durations, namely VSP, short pulse (SP), long pulse (LP) and XLP, were used with fluencies reaching up to 1200 J/cm2, spot size approximately  3-

7 mm, pulse frequency 3-4 Hz and pixel level

3-4 on the handpiece. The number of passes ranged from 4-11 per session and the number of sessions ranged from 4-8 sessions according to the  case, with  a 2-3  week  interval. Conventional, full-field  Er:YAG laser treatments were  started on  the  3rd  to  4th session. The  use   of  Er:YAG treatment modalities, treatment pulse  durations and number of passes applied are summarized in Table(3).

Table (3): Number of passes per treatment modality and selected laser pulse duration mode for use individuaL

Post laser treatment management included topical application of fucidic acid ointment for

3-5 days, soothing cream and sun block with sun protection factor 100. Pre-operative preparations for the next session were then commenced.

Follow-up visits were conducted for up to

2 years at 1-2 month intervals after the end of the last session. Patients were evaluated both subjectively and objectively during each visit. Subjective evaluation was based on both patient satisfaction and surgeon opinion. Patient satisfaction  was rated as "very satisfied", "satisfied" or "dissatisfied".

Objective evaluation was conducted on the basis of evaluation of pre- and post-treatment photos by an independent physician. The objective evaluations were rated as either "excellent",  "very good", "good",  "fair" or

''poor". Any complications during treatment or  after,  such  as  infection, scarring, or pigmentary changes, were  observed  and recorded. Figure(la, 2a, 3a) in group1 and Figure(4a,c,  5a   ,6a,c)  in   group  11

Results:

During the course of our study we treated

120 patients of both sexes suffering from post­ acne sequelae and with skin types ranging from Fitzpatrick type II to type V. Laser therapy was more effective than medium-depth peel.

Subjective  evaluation  showed  a higher

satisfaction rate of 87.5% inthe laser treatment group (group IT), with patients claiming to be "very satisfied" and "satisfied". Satisfaction fell to 52.5% in the chemical peel group (group I), with 28 patients claiming to be "dissatisfied" Table(4).

Table (4): Showing percentage of patient satisfaction in both groups.

The objective evaluation showed "very good" to "excellent" outcome in 75.5% of cases treated in group II based on surgeon opinion and documented photos. In group I,

the medium-deep chemical peel group, outcome was "good" in 47.5% and "fair" in 32.5% of cases Table(5). Figure(lb, 2b, 3b) in group! and  Figure(4b,d, 5b,  6b,d) in  groupll

Table (5): Results of objective evaluation of the clinical end results in the chemical peel and laser treatment group.

Apart from recording a case of bacterial infection in group  I and  a case  of Herpes Simplex  in group II, no other complications or unwanted  side effects were recorded and both treatment modalities were deemed safe. Patients reported a higher degree of aggravation during and immediately after laser treatment than in the chemical peeling group. This was due to the higher incidence of pain during laser

treatments, and erythema, edema and scabbing immediately after treatment sessions.Medium­ depth peeling required more sessions to reach the clinical end-point and was associated with a higher  incidence of pigmentary changes, scarring and  acne  flaring, which  required modification of the post-treatment therapy, than in the laser treatment group  Table(6).

Table (6): Treatment-related complications in the laser treatment and chemical peel groups.

Cases of both groups are illustrated as follows:

Figure (JA):Before (lt.Side).

Figure (JB):After (lt.Side).

Figure (1): Chemical peeling (combined peeling).

Figure (2B):After. Figure (2): Combined Peeling.

Figure (3A):Before.                                                  Figure (3B):After.

Figure (3) : Combined Peeling.

Figure (4A):Before (Rt. Side).                                  Figure (4B):After (Rt. Side).

Figure (4C):Before (Lt. Side).                                  Figure (4D):After (Lt.Side).

Figure (4 A,B): Right side of the face and (C,D) left side: Combined fractional and  Er: YAG

laser.

Figure (5A):Before.                                                 Figure (5B):After.

Figure (5): Before and after left side of the face: Combined fractional and  Er: YAG laser.

Figure (6A):Before (Lt.Side).

Figure (6C):Before (Rt.Side).

Figure (6B):After (Lt.Side).

Figure (6D):After (Rt.Side).

Figure (6 A.B): Left side before and after and (C.D) right side of the face before and after: Combined fractional and  Er: YAG laser.

Disscussion:

Acne  vulgaris carries with it significant psychosocial morbidity, social withdrawal and clinical depression inaddition to the potential for long-term scarring  and disfigurement.B Many systems have been developed for the classification of  acne  scars so  that   the morphology of each scar can be assessed and

treatment designed accordingly. Jacob et al.14 divided a1rophic acne scars into ice pick, rolling and boxcar  scars. Kadunc  and Trindade de AlmeidalS classified acne scars into elevated, dystrophic and  depressed.   Depressed or atrophic scars are contour or volume defects that  may  be distensible or  non-distensible depending on  the  underlying attachment.

Acne is one of the most frequent inflammatory chronic dermatoses. More than

80% of teenagers of both sexes are affected and up to 20% of adults have persistent acne lesions. Post-acne hyperpigmentation and scarring are among the most common sequelae of acne vulgaris. They are cosmetically and psychologically distressing,  especially  for women.16 In our study, 67% of patients were females. We classified patients according to the severity of their post-acne sequelae as minimal, mild, moderate or severe deformity. This allowed us to study the effect of each modality in individual cases.

Several  surgical  techniques have  been investigated to treat  post-acne scarring including punch excision, scar subcision and dermabrasion.17 Depth control is difficult to attain with dermabrasion and scar subcision may need  to be combined with  laser resurfacin.g.lB-20 Resurfacing is one of the most widely used techniques. It involves removing the outer layers down to the level of the papillary dermis, which induces re­ epithelialization and new collagen formation, creating a smoother, even-toned and more youthful appearance.21 Resurfacing  can be achieved by means of chemical peeling or ablative lasers.

Chemical peeling produces a controlled

partial-thickness chemical burn of the epidermis and the outer dermis. Regeneration of peeled skin from follicular and eccrine duct epithelium results in a fresh, orderly  and organized epidermis. In the dermis, a new 2 to 3 mm band of dense, compact and orderly collagen is formed between the epidermis and the underlying damaged dermis. This reduces wrinkles,  scarring  and pigmentation.22-24

Different types of chemical peelings are now being used in medical practice.Phenol produces deep peeling effects that need long periods of healing and may be associated with serious complications including nephrotoxity, hepatoxity and cardiac arrest.23,26 Glycolic acid (GA)  is a superficial peeling  agent. Multiple superficial peels  with  GA are recommended to improve post-acne scars.26

This stimulates dermal fibroblasts to produce collagen decreasing the risk of tissue necrosis and reducing the size of the follicular pores.27

Nevertheless, treatments can  fail  when a superficial peeling  agent  is  used  alone.

Trichloroacetic acid  (TCA)  is another peeling agent. It can produce peelings of medium depth without the serious risks of phenol23,25 and thus remains the gold standard in chemical peeling. It is maximally effective in Fitzpatrick's skin types I-ill. In darker skin types, even TCA 15% or 20% can be fraught with post-peel complications. Undesired side effects such as  post-inflammatory hyperpigmentation and hypopigmentation, infections and hypertrofic scars are frequent. A new form of using TCA, as a selective peeling agent, is in association with GA which helps to promote a greater efficacy in the penetration of TCA. Chelation of the TCA molecule (linking the TCA to aminoacids), on the other hand, does not allow this molecule to penetrate deep into the skin, and because of this, unnecessary necrosis of the dermal1ayer can be avoided.28 The combination of TCA with GA maximizes the peeling effect and diminishes the side effects of using each alone. Addition of GA improves the absorption of lower TCA concentrations and reduces the risk of complications.24

In this study we performed  combined peeling on 60 randomly selected patients, using first GA 70% followed by TCA 15% depending on skin type and thickness. This technique enabled us to induce medium-depth peeling with the least possible side effects and good results.  El-Ammawi26 used  rising concentrations  of GA 20%, 35%, 50% and then 70%. Unlike post-acne hyperpigmentation, the acne scarring did not continue to improve after discontinuing the peeling regime using GA.26

Wang et al.27 recommend repetitive peelings to improve scars. The degree of clinical improvement is proportional to the number of peeling courses with either GA3 or TCA.29

Waiz MM and Al-Sharqi30 and Saleh et a1.31 attributed the higher degree of improvement with TCA 35% with increasing number of sessions to the deeper penetration  of TCA because the skin did not return to the pre-peel thickness in the short interval between sessions. In this study we used medium-depth peeling with GA 70%, followed by TCA 15%. The

therapeutic result is equivalent  to TCA 35% without its adverse effects.28 We agree with previous studies  that the effect  is strongly attributed to the number of sessions; in some cases we performed up to 10 sessions.  The main drawbacks of peeling are the poor patient compliance because of  the long  treatment period  and low persistence of post-peeling effects over time.

Both non-ablative  and ablative  lasers are

used in the treatment of post-acne  scarring. Non-ablative Nd:YAG  laser stimulates new collagen  production by producing  localized thermal injury to the dermis, which initiates a wound healing response.32-34  Recently a Nd:YAG Accelera technology was developed that produces a  three dimensional  fractional thermal injury pattern in the epidermis and dermis. Thermal damage islands located predominantly at  the  sites of  skin imperfections.21,35-37 C02  (10.600  nm) and Er:YAG (2.940 run) are ablative lasers used for treatment  of post-acne  scars through the process of skin resurfacing.10,38 Both lasers are well absorbed by water, but Er:YAG laser has a higher water absorption coefficient and thus higher affinity for water. The cutaneous absorption of the  Er:YAG  laser  energy  by water is 10 fold more efficient than that of the C02 laser allowing for more superficial tissue ablation. It produces less thermal damage but more intraoperative bleeding than C02 laser. However,  post-operative epithelialization is rapid, erythema resolves  significantly faster and the incidence of scarring is low.11,35,38,39

Recently the  fractional technique was introduced based on a concept of producing an array of microscopic  wounds on the skin surface that are rapidly re-epithelialized by the surrounding healthy tissue.40,41 Some fractional Er:YAG lasers have variable pulse durations allowing the effect of the laser to be selected from cold ablation peeling to deeper thermal coagulation for the treatment of atrophic scars, such as acne scars.l2,42

The  incidence of complications in resurfacing procedures is generally related to the depth of ablation and patients' pigmentation problems. Pulse  width  is a key  factor  that

before significant heat diffusion. The Er:YAG laser has the largest range of coagulation depth control,12

In the laser group (group IT) we followed a specific protocol that combines ablative and non-ablative modes with differing fluences and pulse durations. Starting at the 3rd session, we added  the conventional Er:YAG mode. This protocol acted both superficially on the epidermis, through the conventional mode that works by  variable square pulse (VSP) technology, and deep on collagen remodelling through the fractional  mode that works with pixel screen technology (PST) with almost no side  effects. We used  ablative modes  for pigmentation  and to smooth scar edges, also when  we started  with  ablative modes  this removed superficial skin layers which allowed controlled deeper penetration of non ablative modes and better results.

The well-tolerated, fewer sessions and the

short, well controlled downtime together with the efficacy and speed of procedures made this technique popular with  patients. Patient satisfaction was better,  complications were fewer and therapeutic result was long-lasting through the 2-year follow-up  period. Patient satisfaction  indicated 37.5% "very satisfied" in group II in comparison with 17.5% ingroup I.

Saleh et al.31 compared the results of TCA peeling with  conventional Er:YAG laser resurfacing. Their  results  revealed that the overall improvement (irrespective of  the degree) was equal in both groups (60%). Our study showed 30% "excellent" results in the laser  group compared to 5% in the peeling group, and 45.5% "very good" results in the laser group compared to 15% in the peeling group.

Conclusion:

Skin  resurfacing with  medium-depth chemical  peel, using GA followed  by TCA was compared to the combined use of fractional and conventional Er:YAG  laser in patients with post-acne  scarring. The addition of GA in our peeling protocol increased the depth of penetration of  the low concentration TCA

absorption. The  combined Er:YAG laser therapy markedly improved the  results of resurfacing postacne scars and minimized the complications in our dark skin types population. The parameters and regimen recommended in this study were very effective in  the management of post-acne sequel and results were more superior and long lasting than with medium-depth chemical peeling.

Authors have no  financial interests to disclose.

Abbreviations:

C02 is carbon  dioxide laser,

Er:YAG  is Yattrium Aluminum Gamite laser.

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