http://informahealthcare.com/jdt ISSN: 0954-6634 (print), 1471-1753 (electronic) J Dermatolog Treat, Early Online: 1–4 ! 2015 Informa UK Ltd. DOI: 10.3109/09546634.2015.1024597
ORIGINAL ARTICLE
Effectiveness of erbium:YAG laser and cryosurgery in seborrheic keratoses: Randomized, prospective intraindividual comparison study Mehmet Salih Gurel1 and Burcak Bozdemir Aral2 J Dermatolog Treat Downloaded from informahealthcare.com by Nanyang Technological University on 04/26/15 For personal use only.
1
Dermatology Department, Istanbul Training and Research Hospital, Istanbul, Turkey and 2Dermatology Department, Hisar Intercontinental Hospital, Istanbul, Turkey Abstract
Keywords
Background and objective: Seborrheic keratoses (SK) are benign cutaneous lesions frequently seen in old age. The aim of the study is to compare the efficiency of Er:YAG lasers with cryotherapy in the treatment of SK. Patients and methods: The study was carried out on 42 patients with SK sized 0.5–3 cm, located on the back, chest, face and neck. Lesions with a similar size and location on the same patient were matched. In the same session, half of the lesions were treated with cryotherapy, while the other half were treated with Er:YAG lasers. All of the patients were clinically evaluated in two recalls with a one-month interval between appointments. The efficiency of the treatments was clinically evaluated. Results: Following the first treatment, complete healing was detected in all of the lesions (100%) treated with Er:YAG lasers, while the healing rate was 68% in the cryotherapy group (p50.01). In the Er:YAG laser-treated group, hyperpigmentation was significantly lower and more erythema developed than in the cryotherapy group. Conclusion: Er:YAG lasers offer a one-step procedure which is a very simple and economic treatment and provides an alternative treatment method with better cosmetic results compared to cryotherapy.
Benign skin neoplasm, cryosurgery, Er:YAG laser, seborrheic keratose treatment
Introduction Seborrheic keratoses (SK) are common lesions. The lesions usually appear in patients after the age of 30 and become more numerous with advancing age (1). SK are aesthetically important for patients that feel discomfort with them. A variety of therapeutic options are available, however, the use of liquid nitrogen cryotherapy is the most widely practiced (2). The Er:YAG laser is used to ablate or remove benign, premalignant and superficial malignant cutaneous lesions. Although it has been shown to be effective for the treatment of SK, to date there are no qualified trials to evaluate the efficacy and complications of this new treatment (3,4). The aim of this study is to compare the efficacy of Er:YAG lasers with standard liquid nitrogen cryotherapy for the treatment of SK. For this aim, we have evaluated the clinical outcome of Er:YAG laser therapy and cryotherapy in removing SK lesions.
Patients and methods Patients Forty-two patients with SK were enrolled in this randomized, prospective intraindividual (right–left) comparison study. To be considered eligible, a patient had to have SKs of similar size and location on both sides of the body. Two groups were formed by matching a minimum of two similar lesions on each patient. Correspondence: Assoc. Prof. Dr. Mehmet Salih Gurel, Department of Dermatology, Istanbul Training and Research Hospital, Samatya 34098, Istanbul, Turkey. Tel: +90 5323812204. Fax: +90 2126320060. E-mail: [email protected]
History Received 29 September 2014 Revised 22 December 2014 Accepted 22 December 2014 Published online 23 March 2015
A maximum of three pairs of SK lesions on each patient were allowed in the study. Left or right lesion randomization was performed by a coin flip. The patients with a history of keloid, cold intolerance or cryoglobulinemia were not included to study. Those having photosensitive disorders or using drugs that can cause photosensitization were also excluded. The study was performed according to principles in the Declaration of Helsinki. All patients signed an informed consent form prior to the procedure. Lesions A total of 120 SK lesions (0.5–3 cm in size) were treated. The lesions were located on the face, chest, back and upper extremities. Before treatment, each lesion was photographed, numbered and measured. Irritated lesions, with erythema, pain or bleeding were excluded. Study procedure At the baseline visit, eligible subjects received treatment by the same dermatologist with both Er:YAG lasers and conventional liquid nitrogen cryotherapy, randomly allocated to alternate sides of the body. Topical anesthesia (EMLA cream) was applied to all treatment areas. Double freeze–thaw cryotherapy (Brymill CRY-AC, Ellington, CT) was performed using liquid nitrogen spray for at least 10 s (an average 15–20 s) with an applicator size selected to achieve a 1–2mm frozen rim outside the marked outline of the lesion. An Er:YAG laser (Fotona, Twinlight 220A, Ljubljana, Slovenia) with a wavelength of 2940 nm was used in short pulse
2
M. S. Gurel & B. B. Aral
J Dermatolog Treat, Early Online: 1–4
J Dermatolog Treat Downloaded from informahealthcare.com by Nanyang Technological University on 04/26/15 For personal use only.
Table 1. The baseline characteristics of patients and lesions. Sex Male Female Age Mean ± SD Range Localization Facial Neck Back Chest Number of lesions 2 4 6 Lesion diameter Mean ± SD Range
n (%) 27 (64.3) 15 (35.7) (years) 61.60 + 9.94 43–80 N (%) 8 (6.7) 6 (5.0) 70 (58.3) 36 (30.0) N 26 14 2 (cm) 0.74 ± 0.24 0.5–2.3
(ablation) mode with 300– 500 mJ of energy, a frequency of 4–6 Hz and a 3–5 mm spot size. The lesions were removed on a layerby-layer basis. The patients’ eyes were covered with protective goggles and a smoke evacuator was used. To avoid potential bias, the procedures were carried out on the same day. All lesions were evaluated and photographed by two different dermatologists at baseline, weeks 4 and 8. The patients were recalled after 4 weeks and lesion response was classified as either a complete response (CR; complete disappearance of the lesion) or an incomplete response (NR; incomplete disappearance). Lesions with a NR after 4 weeks were retreated but residual lesions after 8 weeks were not retreated. The primary assessments were the lesion response at weeks 4 and 8. Secondary assessments were concerned with the cosmetic outcome and adverse effects including infection, postlesional erythema, hypopigmentation, hyperpigmentation, scar tissue and other structural changes. Differences between these two groups were analyzed using the k-square and Fisher’s exact k-square tests.
Figure 1. Er:YAG laser-treated lesions.
Er:YAG and cryosurgery in seborrheic keratoses
J Dermatolog Treat Downloaded from informahealthcare.com by Nanyang Technological University on 04/26/15 For personal use only.
DOI: 10.3109/09546634.2015.1024597
3
Figure 2. Cryosurgery-treated lesions.
Results A total of 42 patients with 120 SK lesions were included in the study. Each patient received Er:YAG laser and cryotherapy on alternate sides of the body. The baseline characteristics of cases are summarized in Table 1. At the first visit, 4 weeks after the application, 101 of the 120 (84.2%) lesions were completely healed. The remaining 19 lesions were retreated, and all except one were completely healed after 8 weeks (Figures 1 and 2). Lesions treated with Er:YAG lasers were completely healed (100%) after the first treatment session. In the second group, 41 lesions (63.8%) treated with cryotherapy showed a CR at week 4. After the first treatment session, there was a statistically
significant difference in CR rates between the two groups (p50.001). Eighteen of the 19 retreated lesions (31.7%) completely disappeared after the second treatment session at week 8 (Table 2). Erythema, hyperpigmentation and hypopigmentation were the side effects observed in treated lesions. The percentage of these side effects at weeks 4 and 8 was different between the two groups. Analysis of the unwanted adverse effects found after 4 weeks indicated that the Er:YAG laser was more likely to cause erythema than liquid nitrogen treatment but less likely to cause pigmentary changes. All of these findings were statistically significant.
4
M. S. Gurel & B. B. Aral
J Dermatolog Treat, Early Online: 1–4
Table 2. Healing results in treatment methods.
After first treatment After second treatment
Complete healing Incomplete healing Complete healing Incomplete healing
Cryotherapy
Laser
Lesions No. (%)
Lesions No. (%)
41 19 18 1
(68.3%) (31.7%) (4.7%) (5.3%)
60 (100%)a – – –
a
J Dermatolog Treat Downloaded from informahealthcare.com by Nanyang Technological University on 04/26/15 For personal use only.
Ki-kare test p50.01.
Eight weeks after treatment, the erythema rate was the same (23%) for both groups, but the pigmentation rate differed. Cryotherapy produced significantly more hyperpigmentation than the Er:YAG laser, while hypopigmentation reached 83% in the laser-treated group (p50.001). Topical anesthesia was used prior to administration. Therefore, severe pain, or interrupting of therapy due to pain, was not observed in our patients.
Discussion In our study, we compared the efficacy of two different methods for the treatment of SK. The Er:YAG laser can be used to ablate or remove benign, premalignant and superficial malignant cutaneous lesions (5,6). Khatri used the Er:YAG laser in 79 SK lesions and no recurrence was observed (7). In a similar study, complete healing was seen in eight patients with 20 SK lesions after the first session (8). Cryotherapy is a widely used treatment modality in dermatology. The equipment required is simple and relatively inexpensive, which makes cryotherapy an attractive option (9). Although few comparative studies have been published to date, both treatment modalities have been used effectively for SK lesions (2,3,10). Comparing the two different treatment methods on the same subjects eliminates the personal factors that can affect the outcome. Besides, the treatment groups were standardized by selecting lesions from the same area. Some of the reported adverse effects, such as infection, piyogenic granuloma, hypertrophic scars, contact dermatitis and milium formation, were not encountered in both treatment modalities (11,12). Corresponding with other studies, analysis of the adverse effects found after 4 weeks indicated that Er:YAG was more likely to produce erythema than cryotherapy (13,14). Postlesional erythema is a common finding associated with ablative lasers (12). After 8 weeks, this erythema was followed by hypopigmentation. Hyperpigmentation was observed mostly in the cryotherapy group.
The application period is another crucial issue that can affect treatment choice. While the application period is 40–50 se in cryotherapy, with Er:YAG lasers it can range from 90 to 300 s depending on the thickness of the lesion. The Er:YAG laser is an expensive treatment modality compared to cryotherapy. In addition, this technique requires additional equipment and the right circumstances. However, Er:YAG is a predictable one-step procedure and an effective treatment alternative for patients with high cosmetic expectations. As SK lesions are benign, the requirement for high cost laser therapy is an ongoing discussion.
Declaration of interest The authors report no conflict of interest.
References 1. Gill D, Dorevitch A, Marks R. The prevalence of seborrheic keratoses in people aged 15 to 30 years: is the term senile keratosis redundant? Arch Dermatol. 2000;136:759–62. 2. Andrews MD. Cryosurgery for common skin conditions. Am Fam Physician. 2004;69:2365–72. 3. Wood LD, Stucki JK, Hollenbeak CS, Miller JJ. Effectiveness of cryosurgery vs curettage in the treatment of seborrheic keratoses. JAMA Dermatol (Chicago, IL). 2013;149:108–9. 4. Hanke CW, Moy RL, Roenigk RK, et al. Current status of surgery in dermatology. J Am Acad Dermatol. 2013;69:972–1001. 5. Fitzpatrick RE. CO2 and Er:YAG laser resurfacing: practical approaches. Dermatol Ther. 2000;13:102–13. 6. Hohenleutner U, Hohenleutner S, Baumler W, Landthaler M. Fast and effective skin ablation with an Er:YAG laser: determination of ablation rates and thermal damage zones. Lasers Surg Med. 1997; 20:242–7. 7. Khatri KA. Ablation of cutaneous lesions using an erbium:YAG laser. J Cosmet Laser Ther. 2003;5:150–3. 8. Dmovsek-Olup B, Vedlin B. Use of Er:YAG laser for benign skin disorders. Lasers Surg Med. 1997;21:13–19. 9. Thai KE, Sinclair RD. Cryosurgery of benign skin lesions. Aust J Dermatol. 1999;40:175–84; quiz 185–6. 10. Herron MD, Bowen AR, Krueger GG. Seborrheic keratoses: a study comparing the standard cryosurgery with topical calcipotriene, topical tazarotene, and topical imiquimod. Int J Dermatol. 2004;43: 300–2. 11. Graham GF. Advances in cryosurgery during the past decade. Cutis. 1993;52:365–72. 12. Nanni CA. Handling complications of laser treatment. Dermatol Ther. 2000;13:127–39. 13. Ko NY, Ahn HH, Kim SN, Kye YC. Analysis of erythema after Er:YAG laser skin resurfacing. Dermatol Surg. 2007;33:1322–7. 14. Tanzi EL, Alster TS. Single-pass carbon dioxide versus multiplepass Er:YAG laser skin resurfacing: a comparison of postoperative wound healing and side-effect rates. Dermatol Surg. 2003;29:80–4.
ORIGINAL ARTICLE
Effectiveness of erbium:YAG laser and cryosurgery in seborrheic keratoses: Randomized, prospective intraindividual comparison study Mehmet Salih Gurel1 and Burcak Bozdemir Aral2 J Dermatolog Treat Downloaded from informahealthcare.com by Nanyang Technological University on 04/26/15 For personal use only.
1
Dermatology Department, Istanbul Training and Research Hospital, Istanbul, Turkey and 2Dermatology Department, Hisar Intercontinental Hospital, Istanbul, Turkey Abstract
Keywords
Background and objective: Seborrheic keratoses (SK) are benign cutaneous lesions frequently seen in old age. The aim of the study is to compare the efficiency of Er:YAG lasers with cryotherapy in the treatment of SK. Patients and methods: The study was carried out on 42 patients with SK sized 0.5–3 cm, located on the back, chest, face and neck. Lesions with a similar size and location on the same patient were matched. In the same session, half of the lesions were treated with cryotherapy, while the other half were treated with Er:YAG lasers. All of the patients were clinically evaluated in two recalls with a one-month interval between appointments. The efficiency of the treatments was clinically evaluated. Results: Following the first treatment, complete healing was detected in all of the lesions (100%) treated with Er:YAG lasers, while the healing rate was 68% in the cryotherapy group (p50.01). In the Er:YAG laser-treated group, hyperpigmentation was significantly lower and more erythema developed than in the cryotherapy group. Conclusion: Er:YAG lasers offer a one-step procedure which is a very simple and economic treatment and provides an alternative treatment method with better cosmetic results compared to cryotherapy.
Benign skin neoplasm, cryosurgery, Er:YAG laser, seborrheic keratose treatment
Introduction Seborrheic keratoses (SK) are common lesions. The lesions usually appear in patients after the age of 30 and become more numerous with advancing age (1). SK are aesthetically important for patients that feel discomfort with them. A variety of therapeutic options are available, however, the use of liquid nitrogen cryotherapy is the most widely practiced (2). The Er:YAG laser is used to ablate or remove benign, premalignant and superficial malignant cutaneous lesions. Although it has been shown to be effective for the treatment of SK, to date there are no qualified trials to evaluate the efficacy and complications of this new treatment (3,4). The aim of this study is to compare the efficacy of Er:YAG lasers with standard liquid nitrogen cryotherapy for the treatment of SK. For this aim, we have evaluated the clinical outcome of Er:YAG laser therapy and cryotherapy in removing SK lesions.
Patients and methods Patients Forty-two patients with SK were enrolled in this randomized, prospective intraindividual (right–left) comparison study. To be considered eligible, a patient had to have SKs of similar size and location on both sides of the body. Two groups were formed by matching a minimum of two similar lesions on each patient. Correspondence: Assoc. Prof. Dr. Mehmet Salih Gurel, Department of Dermatology, Istanbul Training and Research Hospital, Samatya 34098, Istanbul, Turkey. Tel: +90 5323812204. Fax: +90 2126320060. E-mail: [email protected]
History Received 29 September 2014 Revised 22 December 2014 Accepted 22 December 2014 Published online 23 March 2015
A maximum of three pairs of SK lesions on each patient were allowed in the study. Left or right lesion randomization was performed by a coin flip. The patients with a history of keloid, cold intolerance or cryoglobulinemia were not included to study. Those having photosensitive disorders or using drugs that can cause photosensitization were also excluded. The study was performed according to principles in the Declaration of Helsinki. All patients signed an informed consent form prior to the procedure. Lesions A total of 120 SK lesions (0.5–3 cm in size) were treated. The lesions were located on the face, chest, back and upper extremities. Before treatment, each lesion was photographed, numbered and measured. Irritated lesions, with erythema, pain or bleeding were excluded. Study procedure At the baseline visit, eligible subjects received treatment by the same dermatologist with both Er:YAG lasers and conventional liquid nitrogen cryotherapy, randomly allocated to alternate sides of the body. Topical anesthesia (EMLA cream) was applied to all treatment areas. Double freeze–thaw cryotherapy (Brymill CRY-AC, Ellington, CT) was performed using liquid nitrogen spray for at least 10 s (an average 15–20 s) with an applicator size selected to achieve a 1–2mm frozen rim outside the marked outline of the lesion. An Er:YAG laser (Fotona, Twinlight 220A, Ljubljana, Slovenia) with a wavelength of 2940 nm was used in short pulse
2
M. S. Gurel & B. B. Aral
J Dermatolog Treat, Early Online: 1–4
J Dermatolog Treat Downloaded from informahealthcare.com by Nanyang Technological University on 04/26/15 For personal use only.
Table 1. The baseline characteristics of patients and lesions. Sex Male Female Age Mean ± SD Range Localization Facial Neck Back Chest Number of lesions 2 4 6 Lesion diameter Mean ± SD Range
n (%) 27 (64.3) 15 (35.7) (years) 61.60 + 9.94 43–80 N (%) 8 (6.7) 6 (5.0) 70 (58.3) 36 (30.0) N 26 14 2 (cm) 0.74 ± 0.24 0.5–2.3
(ablation) mode with 300– 500 mJ of energy, a frequency of 4–6 Hz and a 3–5 mm spot size. The lesions were removed on a layerby-layer basis. The patients’ eyes were covered with protective goggles and a smoke evacuator was used. To avoid potential bias, the procedures were carried out on the same day. All lesions were evaluated and photographed by two different dermatologists at baseline, weeks 4 and 8. The patients were recalled after 4 weeks and lesion response was classified as either a complete response (CR; complete disappearance of the lesion) or an incomplete response (NR; incomplete disappearance). Lesions with a NR after 4 weeks were retreated but residual lesions after 8 weeks were not retreated. The primary assessments were the lesion response at weeks 4 and 8. Secondary assessments were concerned with the cosmetic outcome and adverse effects including infection, postlesional erythema, hypopigmentation, hyperpigmentation, scar tissue and other structural changes. Differences between these two groups were analyzed using the k-square and Fisher’s exact k-square tests.
Figure 1. Er:YAG laser-treated lesions.
Er:YAG and cryosurgery in seborrheic keratoses
J Dermatolog Treat Downloaded from informahealthcare.com by Nanyang Technological University on 04/26/15 For personal use only.
DOI: 10.3109/09546634.2015.1024597
3
Figure 2. Cryosurgery-treated lesions.
Results A total of 42 patients with 120 SK lesions were included in the study. Each patient received Er:YAG laser and cryotherapy on alternate sides of the body. The baseline characteristics of cases are summarized in Table 1. At the first visit, 4 weeks after the application, 101 of the 120 (84.2%) lesions were completely healed. The remaining 19 lesions were retreated, and all except one were completely healed after 8 weeks (Figures 1 and 2). Lesions treated with Er:YAG lasers were completely healed (100%) after the first treatment session. In the second group, 41 lesions (63.8%) treated with cryotherapy showed a CR at week 4. After the first treatment session, there was a statistically
significant difference in CR rates between the two groups (p50.001). Eighteen of the 19 retreated lesions (31.7%) completely disappeared after the second treatment session at week 8 (Table 2). Erythema, hyperpigmentation and hypopigmentation were the side effects observed in treated lesions. The percentage of these side effects at weeks 4 and 8 was different between the two groups. Analysis of the unwanted adverse effects found after 4 weeks indicated that the Er:YAG laser was more likely to cause erythema than liquid nitrogen treatment but less likely to cause pigmentary changes. All of these findings were statistically significant.
4
M. S. Gurel & B. B. Aral
J Dermatolog Treat, Early Online: 1–4
Table 2. Healing results in treatment methods.
After first treatment After second treatment
Complete healing Incomplete healing Complete healing Incomplete healing
Cryotherapy
Laser
Lesions No. (%)
Lesions No. (%)
41 19 18 1
(68.3%) (31.7%) (4.7%) (5.3%)
60 (100%)a – – –
a
J Dermatolog Treat Downloaded from informahealthcare.com by Nanyang Technological University on 04/26/15 For personal use only.
Ki-kare test p50.01.
Eight weeks after treatment, the erythema rate was the same (23%) for both groups, but the pigmentation rate differed. Cryotherapy produced significantly more hyperpigmentation than the Er:YAG laser, while hypopigmentation reached 83% in the laser-treated group (p50.001). Topical anesthesia was used prior to administration. Therefore, severe pain, or interrupting of therapy due to pain, was not observed in our patients.
Discussion In our study, we compared the efficacy of two different methods for the treatment of SK. The Er:YAG laser can be used to ablate or remove benign, premalignant and superficial malignant cutaneous lesions (5,6). Khatri used the Er:YAG laser in 79 SK lesions and no recurrence was observed (7). In a similar study, complete healing was seen in eight patients with 20 SK lesions after the first session (8). Cryotherapy is a widely used treatment modality in dermatology. The equipment required is simple and relatively inexpensive, which makes cryotherapy an attractive option (9). Although few comparative studies have been published to date, both treatment modalities have been used effectively for SK lesions (2,3,10). Comparing the two different treatment methods on the same subjects eliminates the personal factors that can affect the outcome. Besides, the treatment groups were standardized by selecting lesions from the same area. Some of the reported adverse effects, such as infection, piyogenic granuloma, hypertrophic scars, contact dermatitis and milium formation, were not encountered in both treatment modalities (11,12). Corresponding with other studies, analysis of the adverse effects found after 4 weeks indicated that Er:YAG was more likely to produce erythema than cryotherapy (13,14). Postlesional erythema is a common finding associated with ablative lasers (12). After 8 weeks, this erythema was followed by hypopigmentation. Hyperpigmentation was observed mostly in the cryotherapy group.
The application period is another crucial issue that can affect treatment choice. While the application period is 40–50 se in cryotherapy, with Er:YAG lasers it can range from 90 to 300 s depending on the thickness of the lesion. The Er:YAG laser is an expensive treatment modality compared to cryotherapy. In addition, this technique requires additional equipment and the right circumstances. However, Er:YAG is a predictable one-step procedure and an effective treatment alternative for patients with high cosmetic expectations. As SK lesions are benign, the requirement for high cost laser therapy is an ongoing discussion.
Declaration of interest The authors report no conflict of interest.
References 1. Gill D, Dorevitch A, Marks R. The prevalence of seborrheic keratoses in people aged 15 to 30 years: is the term senile keratosis redundant? Arch Dermatol. 2000;136:759–62. 2. Andrews MD. Cryosurgery for common skin conditions. Am Fam Physician. 2004;69:2365–72. 3. Wood LD, Stucki JK, Hollenbeak CS, Miller JJ. Effectiveness of cryosurgery vs curettage in the treatment of seborrheic keratoses. JAMA Dermatol (Chicago, IL). 2013;149:108–9. 4. Hanke CW, Moy RL, Roenigk RK, et al. Current status of surgery in dermatology. J Am Acad Dermatol. 2013;69:972–1001. 5. Fitzpatrick RE. CO2 and Er:YAG laser resurfacing: practical approaches. Dermatol Ther. 2000;13:102–13. 6. Hohenleutner U, Hohenleutner S, Baumler W, Landthaler M. Fast and effective skin ablation with an Er:YAG laser: determination of ablation rates and thermal damage zones. Lasers Surg Med. 1997; 20:242–7. 7. Khatri KA. Ablation of cutaneous lesions using an erbium:YAG laser. J Cosmet Laser Ther. 2003;5:150–3. 8. Dmovsek-Olup B, Vedlin B. Use of Er:YAG laser for benign skin disorders. Lasers Surg Med. 1997;21:13–19. 9. Thai KE, Sinclair RD. Cryosurgery of benign skin lesions. Aust J Dermatol. 1999;40:175–84; quiz 185–6. 10. Herron MD, Bowen AR, Krueger GG. Seborrheic keratoses: a study comparing the standard cryosurgery with topical calcipotriene, topical tazarotene, and topical imiquimod. Int J Dermatol. 2004;43: 300–2. 11. Graham GF. Advances in cryosurgery during the past decade. Cutis. 1993;52:365–72. 12. Nanni CA. Handling complications of laser treatment. Dermatol Ther. 2000;13:127–39. 13. Ko NY, Ahn HH, Kim SN, Kye YC. Analysis of erythema after Er:YAG laser skin resurfacing. Dermatol Surg. 2007;33:1322–7. 14. Tanzi EL, Alster TS. Single-pass carbon dioxide versus multiplepass Er:YAG laser skin resurfacing: a comparison of postoperative wound healing and side-effect rates. Dermatol Surg. 2003;29:80–4.
