May 1998Cosmetic Dermatology 27 FACIAL SKIN RESURFACING WITH THE ERBIUM:YAG LASER: NEW FINDINGS Laser resurfacing of facial skin is a very popular method of rhytide and scar removal. Until recent years the most popu- lar methods used for these purposes included dermabrasion and chemabrasion. 1 In the 1990s, the high-energy, short- pulsed carbon dioxide (CO 2 ) laser became the most popular method utilized for these purposes.
Studies have been pub- lished describing multiple methods of treatment with the different high-energy, short-pulsed CO 2 laser systems. 2-5 Histologic evaluation of the impact of different laser sys- tems has been extensively studied. 6 The short and long-term side effects of carbon dioxide laser resurfacing performed by multiple operators 7 and by a single operator 8 have been re- ported.
Despite the dramatic results seen with high-energy, short-pulsed CO 2 laser resurfacing of facial skin, the enthu- siasm for these systems has been diminished by the pro- longed recovery time, the persistent erythema seen in many patients and the limited safety margins leading to perma- nent side effects even in the hands of experienced laser sur- geons. he Erbium:YAG (Er:YAG) laser, with its 2940 nanometer (nm) wavelength, produces energy in the mid-infrared invisible light ... more. less.
spectrum. 9 This wavelength has 10-15 times greater water absorption than the CO 2 laser at 10,600 nm wavelength.<br><br> 10 The Er:YAG laser produces a pulse of 250-350 microseconds, which is less than the one mil- lisecond thermal relaxation time of the skin. Also, the Er:YAG laser causes tissue ablation with very little tis- sue vaporization and desiccation. 11 The ablation threshold of the Er:YAG laser for human skin has been calculated to 1.6 J/cm 2(12) as compared to 5 J/cm 2(13) calculated high-energy, short-pulsed CO 2 laser systems.<br><br> The Er:YAG laser is so exquisitely absorbed by water that it causes 10-40 microns of tissue ablation and thermal damage zones of 5-30 microns (depend- ing on the parameters used), specifically 2-15 microns at 4.2 J/cm 2 . 12,14,15 In contrast, the high-energy, short- pulsed CO 2 laser causes 100-120 microns of tissue damage which is composed of 50-60 microns of appar- ent tissue desiccation (ablation or coagulation) and an additional 50-75 microns of thermal damage. 6,16 Be- cause of the predictable penetration of the Er:YAG laser, more passes are required to achieve an equal level of penetration into the dermis as compared to the high-energy, short-pulsed CO 2 laser systems.<br><br> How- ever, for this comparable level of tissue ablation, there is significantly less thermal damage. This allows for more precise control for tissue ablation and less resid- ual thermal damage. As demonstrated with the different high-energy, short-pulsed CO 2 , 17 dermabrasion 18 and deep chemical peels, 19 tightening of the skin occurs also after Er:YAG laser facial resurfacing 20 via dermal remodeling in- duced by new collagen formation.<br><br> The objective of this study is to report our clinical experience with laser resurfacing of the face with class III rhytides using the Er:YAG laser. In addition, we re- port on the histologic evaluation of Er:YAG laser resurfacing of human ex vivo facial skin. Materials and Methods Fourteen patients were included in this study.All pa- tients were treated for facial rhytides.<br><br> All patients have Fitzpatrick skin phenotypes I-III. The patients 9 ages range from 50-75 years old. All patients showed class III rhytides.<br><br> Five patients underwent full face laser resurfacing, including the perioral and perior- bital regions. Four patients had laser resurfacing of only the perioral region. Another four patients had laser resurfacing of only the periorbital region.<br><br> One patient had resurfacing of both the perioral and peri- orbital regions. The type of laser utilized was the Er:YAG (Continuum Biomedical Inc., division of Con- tinuum Electro-Optics, Dublin, CA). The fluence uti- lized in all patients ranged from 5 J/cm 2 at 10 pulses/sec, well above the necessary ablation thresh- old.<br><br> The shoulders of each one of the rhytides were treated with 2-3 passes with the 2 mm spot size at 0.l74 J. Then the whole area to be treated was resur- faced with the following parameters: the periorbital area was treated with 4 passes of the Er:YAG laser; the perioral area 5-6 passes; the rest of the face including the cheeks, chin and forehead 7-8 passes using the 5 mm spot size at 1 J. The first 2 passes were stacked pulses with no more than 10% adjacent skin overlap.<br><br> Then, the treated areas were rehydrated with gauzes by Maritza I. Perez, M.D. and David E.<br><br> Bank, M.D. Maritza I. Perez, M.D.<br><br> is associate clinical professor of dermatology at Columbia University. David E. Bank, M.D.<br><br> is clinical assistant professor of dermatology at Columbia University. impregnated with xylocaine 1% and epinephrine. Once the tissue was rehydrated and the patient felt the area numbed by the xylocaine, the subsequent passes were then delivered stacked and with no more than 10% overlap of the adjacent skin.<br><br> In all cases these parameters removed the rhytides or showed blood-tinged oozing which was used as the end point. Apotent vacuum apparatus (Medlek Devius Inc., Buf- falo, NY) was utilized next to the laser handpiece to aspirate the plume of ablated tissue. The pre-operative evaluation included a complete history and physical exam, complete chemistry, blood counts, PT and PTT.<br><br> In preparation for surgery, the patients were instructed to avoid tobacco, alcohol, as- pirin and non-steroidal, anti-inflammatory or anti-co- agulant medications for 10 days prior to the proce- dure. Athorough history of previous and current medications, especially isotretinoin, was obtained. History of previous wound healing, pigmentary prob- lems and previous history of viral and bacterial infec- tions were obtained.<br><br> Patients with any medical condi- tion (cardiovascular, respiratory, psychological or immunologic deficiency), history of hypertrophic scar- ring or keloid formation, history of isotretinoin ther- apy less than 6 months prior to treatment and history of any recurrent or chronic viral disease were not con- sidered for the study.All treated patients, despite an absence of a previous history of bacterial or viral in- fections, were given Valtrex 500 mg twice daily for a week and Cefalexin 250 mg four times a day for ten days starting on the day before surgery.All patients applied topical tretinoin every night for at least two weeks before surgery. On the day of surgery the patient applied EMLA (Astra Pharmaceutical Products Inc., Westborough, MA) 1 1/2-2 hours before the procedure. The areas to be treated were cleansed with 4% Betasept (Purdue Frederick Co., Norwalk, CT) followed by sterile saline.<br><br> Supplementary anesthesia included xylocaine 1% with epinephrine 1:100,000 either by injection with a 30- gauge needle or applied topically by impregnated gauze. Some of the patients who had periorbital Er:YAG laser resurfacing received field block with xy- locaine with epinephrine. All patients treated in the periorbital area wore eye shields (Ellis Instruments Inc., Madison, NJ) during the procedure.<br><br> Patients who underwent full face resurfacing were covered post-operatively with a semipermeable trans- parent membrane (N-terface, Winfield Laboratories Inc., Dallas, TX) for 24 hours after treatment. Those who received perioral treatment were covered with extra-thin Duoderm (Convatec, division of LR Squibb and Son, Princeton, NJ), and those with periorbital resurfacing received a thick layer of bland emollient (Aquaphor healing ointment, Beiersdorf Inc., Nor- walk, CT). After 24 hours, all patients were instructed to apply acetic acid compresses (one teaspoonful per cup of tap water) twice daily followed by Aquaphor application.<br><br> Total sun avoidance was encouraged. Pa- tients were followed on a daily basis until re-epithe- lialization occurred as determined by confluent ery- thema without erosion, and weekly until disappearance of erythema. After re-epithelialization was observed, all patients were started on a tinted 60 SPF sun block (Fallene Ltd., King of Prussia, PA) and followed for 1 to 6 months.<br><br> All patients were photographed before treatment, during the healing process and a few months after the procedure. All pictures were evaluated by two differ- ent blinded observers who had to determine the be- fore and after pictures and categorize the improve- ment as follows: 0=no improvement; 1=mild improvement (<25%); 2=moderate improvement (25- 50%); 3=marked improvement (>50%). The blinded observers used global rhytide evaluation.<br><br> Facial skin was obtained from the preauricular area and intended for skin grafts to close defects created after Mohs surgery. This ex vivo human facial skin was treated with increasing passes of the Er:YAG laser and submitted for histopathological evaluation in or- der to determine the level of penetration by the laser. Results Ten patients were female and four were male.<br><br> The av- erage age of our patients was 68 years old. The aver- age healing time after Er:YAG laser was 3.8 days (ranging from 2-4 days). Marked redness changed to mild pink in average by 7.7 days (ranging from 6-9 days).<br><br> All evidence of erythema resolved between 3-8 weeks in all patients. All patients demonstrated some improvement. Marked improvement was seen in eight of the fourteen patients in whom 50-75% of class III rhytides (sharply defined deep lines with dermal elas- tosis and skin folds) improved.<br><br> Moderate improve- ment was seen in six of fourteen patients in whom 25- 50% of class III rhytides improved. The most dramatic improvement was noticed after full face resurfacing with the Er:YAG laser of a 70 y e a r-old woman with class III rhytides, pre m a l i g n a n t skin changes and facial dyschromia as shown in Figure 1 (Aand B, before and after). Pre - c a n c e rous lesions and dyschromia disappeared, as well as most of the class III rhytides which either disappeared or became class I rhytides.<br><br> Figure 2Ashows class III rhytides on 28 Cosmetic Dermatology May 1998 May 1998Cosmetic Dermatology 29 the outer canthus of a 65 year-old male who works outdoors, and shows extensive sun damage as com- p a red to his marked improvement 5-6 weeks after E r : YAG laser resurfacing of the periorbital region (Fig. 2B). Figure 3Ashows perioral and periorbital class III rhytides in a 68 year-old woman who demonstrated 50-75% improvement 8 months after Er:YAG laser resurfacing (Fig.<br><br> 3B). In contrast with the static im- Figure 1A: 70 year-old white female before full face Er:YAG laser resurfacing. Figure 1B: Same woman 2 weeks after Er:YAG laser full face resurfacing.<br><br> Figure 2A: 65 year-old white male with periorbital class III rhytides. Figure 2B: 50-75% improvement 1 1/2 months after Er:YAG laser resurfacing of the periorbital region. 30 Cosmetic Dermatology May 1998 p rovement observed in patients resurfaced with the h i g h - e n e rg y, short-pulsed CO 2 lasers, the patients resurfaced with the Er:YAG laser keep improving with time up to approximately 6 months after tre a t m e n t .<br><br> The histologic evaluation of the skin grafts donor skin treated with the Er:YAG laser revealed the fol- lowing findings: Figure 4Ashows that after one pass with the Er:YAG laser there is ablation of the epidermis down to the granular layer under which a thin layer of thermal damage lies and the sub- granular keratinocytes show intracellular edema. In F i g u re 4B, after 2-3 passes with the laser there is ablation of the epidermis down to the basal cell l a y e r, minimal thermal damage and swollen basal cell keratinocytes as well as slight reactive changes of the papillary dermis seen as compacted collagen. After 4-5 passes, full thickness ablation of the epi- dermis and the upper papillary dermis with a re a c- tive papillary dermis demonstrating loss of the fas- cicle-like arrangement of the collagen and perpendicular orientation of the collagen fibers is shown (Fig.<br><br> 4C). After 6-7 passes with the laser (Fig. 4D), there is total ablation of the epidermis and the papillary dermis with very little thermal n e c rosis.<br><br> The papillary, superficial and mid-re t i c u- lar dermis show loss of the fascicle arrangement of the collagen and perpendicular orientation of the collagen fibers. Discussion Rhytidectomies, blepharoplasties, varied-penetration chemical peels and dermabrasion, liposuction and injection of filler substances are a few of the tre a t- ments sought to improve imperfections of the skin and to regain a youthful appearance. 1 , 2 1 - 2 4 The in- c reased interest in rejuvenation has fostered rapid technological development of a variety of char- f re e carbon dioxide lasers used for skin re s u r f a c i n g .<br><br> 2 - 7 Some consider the high-energ y, short-pulsed CO 2 laser better suited for well-controlled removal of thin layers of skin as compared to chemical peeling and dermabrasion of the facial skin. 2 4 , 2 5 Hence, the h i g h - e n e rg y, short-pulsed CO 2 laser resurfacing of the skin has become a very popular modality for the t reatment of facial rhytides, acne scars, post-trau- matic scars and even post-surgical scars. The high- e n e rg y, short-pulsed CO 2 laser systems expose the t reated area to energy above the ablation thre s h o l d of 5 J/cm 2 calculated for them.<br><br> However, excessive thermal damage can be produced by these diff e re n t systems. Depth of ablation for the super-pulsed and flash-scanning CO 2 lasers has been calculated as 30- 50 microns by Kauvar et al 6 , and for the high-energ y, short-pulsed CO 2 laser as 20-30 microns, with addi- tional thermal necrosis ranging from 50-150 micro n s p roportional to the number of laser passes over the t a rget tissue. In contrast, the pulse Er:YAG laser 9 s Figure 3A: 68 year-old white female with class III rhytides in the periorbital and perioral region.<br><br> Figure 3B: Eight months after Er:YAG laser resurfacing of the perioral and periorbital region. May 1998Cosmetic Dermatology 33 Figure 4C: After 4-5 passes there is full thickness epidermal and some papillary dermis ablation with minimal thermal damage and significant papillary dermis reaction. Figure 4D: After 6-7 passes there is full epidermal thickness ablation down to papillary and superficial reticular dermis with minimal thermal damage and mid- reticular dermis reaction.<br><br> Figure 4A: After 1 pass with the Er:YAG laser, upper half of epidermis shows ablation, with a very thin layer of thermal damage under it followed by 2 layers of keratinocytes with intracellular edema. Figure 4B: After 2-3 passes there is epidermal ablation down to the basal cell layer/dermoepidermal juncture with limited thermal damage and the residual basal cell keratinocytes showing intracellular edema and slight papillary reaction. 34 Cosmetic DermatologyMay 1998 wavelength (2940 nanometers) may provide the ideal re q u i rements for skin rejuvenation.<br><br> Its tissue water absorption is ten times as effective as that of any CO 2 l a s e r. 9 , 1 0 Also, the ablation threshold for the E r : YAG laser has been calculated as 1.6 J/cm 2 , as c o m p a red to 5 J/cm 2 for the high-energ y, short- pulsed CO 2 lasers. Each laser impact ablates 25-40 m i c rons of tissue with as little as 5 microns of ther- mal damage.<br><br> 9 , 1 0 - 1 2 , 2 6 , 2 7 The diff e rent measurements of tissue ablation and thermal damage depends on the fluences used. Even, overlapping pulses at 4 J/cm 2 applied in a sweeping motion has proven to be opti- mal for efficient tissue ablation and with total cumu- lative thermal damage never exceeding 50 micro n s . 1 2 These features of the Er:YAG laser provide for both highly controlled tissue ablation necessary for fine, superficial resurfacing of the skin.<br><br> 2 8 This has been demonstrated by ourselves 2 8 and others 2 9 in vivo by a shorter healing period and the dramatically shorter post-treatment erythema as compared to the C O 2 lasers. In addition, the Er:YAG laser has a bacte- rial eff e c t 3 0 that might prevent the infection rate of 4% seen with the pulsed-CO 2 laser resurfacing for photoaged skin. 3 1 Our findings show that the Er:YAG laser can be used effectively for resurfacing of deep class III rhytides.<br><br> We also confirm findings of others 2 9 demonstrating shorter healing period and dramati- cally shorter post-treatment erythema in patients t reated with the Er:YAG laser than those tre a t e d with the high-energ y, short-pulsed CO 2 laser for fa- cial resurfacing. These results also suggest one set of parameters that yield optimal results in facial laser resurfacing with the Er:YAG laser, 5 J/cm 2 , stacked pulses, 3-8 passes depending on the area to be t reated. Furthermore, this report is helpful in deter- mining the level ablation and the coagulation para- meters, as determined by histologic evaluation, de- pending on the number of passes over the skin.<br><br> Additional challenges reside in the treatment of darker Fitzpatrick skin types (>skin type III), the t reatment of conditions other than facial cutaneous types such as the aging hands and neck and in im- p roving the cosmetic results of skin grafting fol- lowed by resurfacing. s References 1. Fulton JD.<br><br> Dermabrasion, chemabrasion and laser abrasion. Historical perspectives, modern der- mabrasion techniques and future trends. Dermatol Surg.<br><br> 1996;22:619-628. 2 . Fitzpatrick RE, Goldman MP, Satur NM, To p e WD.<br><br> Pulse carbon dioxide laser resurfacing of photoaged facial skin. A rch Dermatol. 1 9 9 6 ; 1 3 2 : 3 9 5 - 4 0 2 .<br><br> 3. Waldorf HA, Kauvar AN, Geronemus RG. 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