Er:YAG laser skin resurfacing using repetitive long-pulse exposure and cryogen spray cooling: I. Histological study

BACKGROUND AND OBJECTIVE: To evaluate histologically the characteristics of repetitive Er:YAG laser exposure of skin in combination with cryogen spray cooling (CSC), and its potential as a method of laser skin resurfacing. STUDY DESIGN/MATERIALS AND METHODS: Rat skin was irradiated in vivo with sequences of 10 Er:YAG laser pulses (repetition rate 20 Hz, pulse duration 150 or 550 micros, single-pulse fluence 1.3-5.2 J/cm(2)). In some examples, CSC was applied to reduce epidermal injury. Histologic evaluation was performed 1 hour, 1 day, 5 days, and 4 weeks post-irradiation. RESULTS: A sequence of ten 550-micros pulses with fluences around 2 J/cm(2) resulted in acute dermal collagen coagulation to a depth of approximately 250 microm, without complete epidermal ablation. CSC improved epidermal preservation, but also diminished the coagulation depth. Four weeks after irradiation, neo-collagen formation was observed to depths in excess of 100 microm. CONCLUSIONS: Dermal collagen coagulation and neo-collagen formation to depths similar to those observed after CO(2) laser resurfacing can be achieved without complete ablation of the epidermis by rapidly stacking long Er:YAG laser pulses. Application of CSC does not offer significant epidermal protection for a given dermal coagulation depth.     

Er:YAG Laser Resurfacing Using Combined Ablation and Coagulation Modes

BACKGROUND: The two main laser types used in resurfacing, the CO2 and the Er:YAG lasers, have their supporters and detractors, and each system has clear advantages and disadvantages. OBJECTIVE: The Er:YAG laser can be used in the usual efficient ablative mode, followed by reprogramming to achieve nonablative deeper dermal coagulation associated with the CO2 laser, thereby achieving the main advantages of both laser types. PATIENTS AND METHODS: Twenty-three female patients, ages 42-72 yrs, skin types I-IV, were treated. The epidermis was first removed in the ablative settings in a single pass with 50% overlap. The Er:YAG laser was reprogrammed for the subablative mode, and several passes produced controlled residual thermal damage (RTD) without further ablation. RESULTS: At 2 months postresurfacing the results were assessed. Thirteen patients were rated "very good," eight as "good," and two as "fair." CONCLUSION: The dual mode Er:YAG laser can first be used in the ablative mode to remove the epidermis with minimal RTD, following which, in the subablative mode, the same laser induces a controlled layer of dermal RTD, stimulating the dermis to achieve collagenesis and collagen remodeling and giving good long-term results.     

Er:YAG laser skin resurfacing using repetitive long-pulse exposure and cryogen spray cooling: II. Theoretical analysis

BACKGROUND AND OBJECTIVE: To analyze the effects of laser pulse duration and cryogen spray cooling (CSC) on epidermal damage and depth of collagen coagulation in skin resurfacing with repetitive Er:YAG laser irradiation. STUDY DESIGN/MATERIALS AND METHODS: Evolution of temperature field in skin is calculated using a simple one-dimensional model of sub-ablative pulsed laser exposure and CSC. The model is solved numerically for laser pulse durations of 150 and 600 microsec, and 6 msec cryogen spurts delivered just prior to ("pre-cooling"), or during and after ("post-cooling") the 600 microsec laser pulse. RESULTS: The model indicates a minimal influence of pulse duration on the extent of thermal effect in dermis, but less epidermal damage with 600 microsec pulses as compared to 150 microsec at the same pulse fluence. Application of pre- or post-cooling reduces the peak surface temperature after laser exposure and accelerates its relaxation toward the base temperature to a different degree. However, the temperature profile in skin after 50 msec is in either example very similar to that after a lower-energy laser pulse without CSC. CONCLUSIONS: When applied in combination with repetitive Er:YAG laser exposure, CSC strongly affects the amount of heat available for dermal coagulation. As a result, CSC may not provide spatially selective epidermal protection in Er:YAG laser skin resurfacing.     

Laser resurfacing with a long pulse erbium:YAG laser compared to the 950 ms pulsed CO(2) laser

BACKGROUND AND OBJECTIVE: Laser resurfacing with the 950 micros pulsed CO(2) laser is an effective treatment for photodamage and acne scarring; however, the potential for prolonged erythema and delayed re-epithelialization dissuade many patients from the procedure. With the use of erbium lasers alone, there is a decrease in the incidence and severity of these adverse sequelae; however, it is difficult to achieve the same degree of improvement as with the CO(2) laser because of the more superficial depth of resurfacing. Thus, new erbium lasers have been developed with longer pulse durations to deliver increased thermal effects to tissue. It is hypothesized that with the use of these lasers, diminished erythema and faster wound healing will be observed as well as enhanced clinical outcomes. STUDY DESIGN/MATERIALS AND METHODS: Sixteen patients were randomized to receive laser resurfacing on one-half of the face with the 950 micros pulsed CO(2) laser (UPCO(2)) followed by short pulse erbium:YAG ablation, and to the other half with a variable pulsed erbium laser (VP Er:YAG) followed by traditional short pulse erbium laser. Patients were evaluated clinically before resurfacing and at 1, 2, 4, 8, and 12 weeks post-operatively. Histologic samples taken at various time periods before and after resurfacing were also evaluated. RESULTS: Overall clinical improvement was equal for both UPCO(2) and VP Er:YAG treated sides with an average improvement in photoaging scores of 57%. Decreased erythema, less edema, and faster healing were observed on the VP Er:YAG treated side. CONCLUSION: The VP Er:YAG laser can achieve a similar degree of improvement as seen with short pulse CO(2) laser resurfacing with decreased thermal tissue effects and decreased risk for adverse sequelae.     

Ex vivo histological characterization of a novel ablative fractional resurfacing device

BACKGROUND AND OBJECTIVES: We introduce a novel CO(2) laser device that utilizes ablative fractional resurfacing for deep dermal tissue removal and characterize the resultant thermal effects in skin. STUDY DESIGN/MATERIALS AND METHODS: A prototype 30 W, 10.6 microm CO(2) laser was focused to a 1/e(2) spot size of 120 microm and pulse duration up to 0.7 milliseconds to achieve a microarray pattern in ex vivo human skin. Lesion depth and width were assessed histologically using either hematoxylin & eosin (H&E) or lactate dehydrogenase (LDH) stain. Pulse energies were varied to determine their effect on lesion dimensions. RESULTS: Microarrays of ablative and thermal injury were created in fresh ex vivo human skin irradiated with the prototype CO(2) laser device. Zones of tissue ablation were surrounded by areas of tissue coagulation spanning the epidermis and part of the dermis. A thin condensed lining on the interior wall of the lesion cavity was observed consistent with eschar formation. At 23.3 mJ, the lesion width was approximately 350 microm and depth 1 mm. In this configuration, the cavities were spaced approximately 500 microm apart and interlesional epidermis and dermis demonstrated viable tissue by LDH staining. CONCLUSION: A novel prototype ablative CO(2) laser device operating in a fractional mode was developed and its resultant thermal effects in human abdominal tissue were characterized. We discovered that controlled microarray patterns could be deposited in skin with variable depths of dermal tissue ablation depending on the treatment pulse energy. This is the first report to characterize the successful use of ablative fractional resurfacing as a potential approach to dermatological treatment.     

Resurfacing of Pitted Facial Acne Scars Using Er:YAG Laser with Ablation and Coagulation Mode

Although the conventional, short-pulsed erbium: yttrium-aluminum-garnet (Er:YAG) laser provides substantial clinical improvement for pitted, facial acne scars, it shows less effective hemostasis and limited residual thermal effect in the dermis. Recently, dual-mode Er:YAG laser systems with both ablation and coagulation modes have been developed. The purpose of this study was to evaluate the clinical and histologic effects of resurfacing pitted, facial acne scars with a dual-mode Er:YAG laser. Twenty patients with pitted facial acne scars underwent laser resurfacing using a computerized-scanning, dual-mode Er:YAG laser. All patients had Fitzpatrick skin types ranging III–V. Initially, the epidermis was removed in two passes using the ablative settings. This step was followed by two passes in a mixed ablation and coagulation mode, to produce further ablation and controlled, residual thermal damage. A final pass in a ablation mode was used to remove necrotic tissue. Laser overlapping was approximately 30%. The results of laser treatment were evaluated for the degree of clinical improvement, duration of erythema, pigmentary change, and any adverse events at two weeks, one month, and three months. In two patients, skin biopsies were obtained at the following intervals: immediately and two weeks postoperatively for histologic examination. There was a 75% average clinical improvement observed in pitted, facial acne scars after laser treatment. Complete wound healing occurred between six and eight days. On histologic examination, complete re-epithelialization was observed at two weeks. Erythema occurred in all patients after laser treatment and lasted longer than three months in 10 patients (50%). Post-inflammatory hyperpigmentation occurred in 12 patients (60%) two to four weeks after laser treatment and lasted longer than three months in one patient (5%). One patient (5%) experienced mild hypopigmention. Mild to moderate, postoperative acne flare-up occurred in seven patients (35%). No other adverse effects were observed. In conclusion, resurfacing with a dual-mode Er:YAG laser is a safe and effective treatment modality for pitted, facial acne scars.     

Variable pulse erbium:YAG laser skin resurfacing of perioral rhytides and side-by-side comparison with carbon dioxide laser

BACKGROUND AND OBJECTIVE: Laser resurfacing of facial rhytides has become a popular treatment option for many patients with wrinkles, photoaging, and acne scarring. Laser wavelength/pulse duration options and new techniques continue to shorten the healing phase associated with laser skin resurfacing while maintaining clinical efficacy. Variable pulse erbium:YAG (Er:YAG) laser systems are now available that offer the surgeon the ability to vary the Er:YAG pulse duration from a pulse that is primarily ablative to one that is more thermal. The objective of this study was to evaluate the histologic effects created with a variable pulse Er:YAG laser. To study prospectively the clinical effects on upper lip rhytides with a variable pulse Er:YAG laser when compared side by side with pulsed carbon dioxide (CO(2)) laser resurfacing. STUDY DESIGN/MATERIALS AND METHODS: Forty-two treatment sites on 21 patients were randomized and evaluated after treatment of the upper lip region with CO(2) laser resurfacing on one side and a variable pulse Er:YAG laser on the other. Patient diaries were maintained to assess erythema, crusting, pain, and pigmentary changes. Blinded objective grading of improvement was performed. Chromometer measurements were obtained to analyze erythema. RESULTS: The variable pulse Er:YAG laser treatment reduced the duration of crusting on average from 7.7 days with CO(2) to 3.4 days. Chromometer measurements noted decreased postoperative erythema. Grading by physicians in a blinded manner showed 63% improvement for the CO(2) treatment site and 48% improvement in the variable pulse Er:YAG site. No cases of permanent hyperpigmentation, hypopigmentation, or scarring occurred. CONCLUSION: The variable pulse Er:YAG laser resurfacing is a safe and effective resurfacing tool, which combines ablative and thermal modalities. The protocol used in this study approaches but does not equal the results we have traditionally seen with CO(2) laser resurfacing.     

Deep coagulation of dermal collagen with repetitive Er:YAG laser irradiation

BACKGROUND AND OBJECTIVE: Er:YAG lasers are known to effectively ablate human skin with minimal thermal damage to subjacent dermal tissue. We have investigated whether deep coagulation of dermal collagen, similar to that observed with the CO(2) laser, could be achieved with repetitive Er:YAG laser exposures. STUDY DESIGN/MATERIALS AND METHODS: Skin on the back of a Sprague-Dawley rat in vivo was irradiated with sequences of 1-10 Er:YAG laser pulses at a repetition rate of 10 or 33 Hz and single-pulse fluences from 0.8 to 1.4 J/cm(2). The resulting lesions were biopsied within 1 hour after laser exposure, and the histologic sections were examined by using optical microscopy. RESULTS: The depth of dermal collagen denaturation increases dramatically when 3-10 low-fluence Er:YAG laser pulses are stacked at a repetition rate of 10 or 33 Hz. CONCLUSION: Coagulation of dermal collagen deeper than 200 microm below the epidermal-dermal junction is feasible by using the appropriate settings of a repetitive Er:YAG laser.     

Histologic Effect of a Variable Pulsed Er:YAG Laser

BACKGROUND: Carbon dioxide (CO2) lasers used for laser resurfacing produce significant thermal damage. Short-pulsed Er:YAG lasers provide significant control over depth of ablation with minimal thermal damage. Newer combined short-pulsed/long-pulsed Er:YAG lasers offer the potential for both precise control over depth of ablation and degree of chosen thermal damage. OBJECTIVE: To determine the correlation between the histologic effects of an ablative short-pulsed Er:YAG laser and/or a thermally damaging longer-pulsed Er:YAG laser and the findings chosen on the touch panel of such a machine. METHODS: In situ lasing of abdominoplasty specimens was undertaken. Various depths of ablation and/or thermal effect were chosen on the machine. The tissue was laser irradiated, histologically analyzed, and ablation/thermal depths of damage were analyzed by a blinded dermatopathologist. RESULTS: Postlaser histologic depths of ablation after short-pulsed Er:YAG laser resurfacing correlated well with those chosen on the machine. However, when a longer, thermally damaging Er:YAG laser pulse was chosen, chosen ablative and/or thermal depths of damage showed histologic correlation only for the first pass. With repeated passes, using the variable pulse width, the histologic depth of ablation and residual thermal damage do not match the settings on the machine. CONCLUSION: A dual-mode Er:YAG laser provides the histologic control over depth of ablation seen with all short-pulsed Er:YAG lasers. In addition, the histologic thermal effect desired from CO2 lasers could be observed when such a system is used with longer Er:YAG laser pulses. Good correlation between chosen laser parameters and histologic findings are seen with all chosen levels of short-pulsed Er:YAG laser parameters. Good correlation is seen between the chosen laser parameters and histologic findings after a first pass of either a longer pulsed thermal damaging Er:YAG laser alone or in combination with a shorter pulsed ablative Er:YAG laser. However, subsequent laser passes in these modes showed poor correlation between the chosen laser parameters and histologic effect. Such findings have important implications when such a laser is used clinically.     

Correlation of histological findings of single session Er:YAG skin fractional resurfacing with various passes and energies and the possible clinical implications

BACKGROUND AND OBJECTIVES: Ablative fractional resurfacing shows promise for skin resurfacing and tightening and also to improve treatment of epidermal and dermal pigmentary disorders. This study aimed at determining any correlation between epidermal ablation and effects on the dermis when using an Er:YAG laser in ablative fractional resurfacing mode. MATERIALS AND METHODS: Ten female subjects participated in the study, mean age 52 years, Skin phototypes: 1 Fitzpatrick type II; 8 type III and 1 type IV. The degree of wrinkles (Glogau scale II or III) was similar in all cases. The laser used was the Pixel Er:YAG system (Alma Lasertrade mark, Israel) which delivers the laser beam via a hand-piece equipped with a beam splitter to divide the 2,940 nm beam into various microbeams of 850 microm in diameter in an 11 mmx11 mm treatment area. Using a constant energy of 1,400 mJ/cm(2), on a test area of 4 cmx2 cm. Two, 4, 6, and 8 passes on the preauricular area of the face were evaluated immediately after treatment. In all cases, the handpiece was kept in the same position, and rotated slightly around its perpendicular axis between passes, then moved on to the next spot. Biopsies were performed and tissue samples were routinely processed and stained with hematoxylin and eosin (H&E). RESULTS: No patient reported any noticeable discomfort, even at 8 passes. The histological findings revealed that, independent of the degree of the wrinkles, more laser passes produced more ablative removal of the epidermis. Residual thermal damage (RTD) with 2 laser passes was not observed but with 4 and 6 passes increased thermal effects and vacuole formation in the epidermal cells were noticed. With 8 laser passes, total epidermal removal was seen together with frank RTD-related changes in the upper part of the papillary dermis. CONCLUSION: In this study, we have demonstrated that high density fractional Er:YAG laser energy in a single session with multiple passes targeted not only the skin surface with elimination of the epidermis, but could also achieve heat deposition in the upper dermis. When performing ablative fractional resurfacing with an Er:YAG laser, treatment of varying degrees of damage could be achieved by varying the number of passes.     

Combined Laser Resurfacing with the 950-μsec Pulsed CO2+ Er:YAG Lasers

INTRODUCTION: Laser resurfacing with the 950 microsec pulsed CO2 laser has been proven to be efficacious in improving photodamaged skin and acne scarring. Unfortunately, prolonged erythema and delayed wound healing are common adverse sequelae, which require intensive patient education and intervention. These adverse effects may be due to the degree of nonspecific thermal damage present after resurfacing with the CO2 laser. Since erbium: YAG (Er:YAG) laser vaporization leaves far less thermal damage, it is hypothesized that its use after CO2 laser resurfacing will decrease the extent of nonspecific damage and result in improved wound healing. METHODS: Ten patients were randomized to receive laser resurfacing of one-half of the face with the 950 Msec pulsed CO2 laser with 3 passes at 300 mJ, utilizing the computer pattern generator (CPG) at settings of 596, 595, 584, and the other half of the face (randomly chosen) resurfaced with the 950 Msec pulsed CO2 laser 2 passes with the CPG at 300 mJ at settings of 596 and 595, followed by 2 passes with the Er:YAG laser (Derma-20 or Derma-K, ESC Medical Systems, Inc., Needham, MA) with a 4 mm diameter spot size at 1.7 J (approximately 14 J/cm2). Patients were evaluated in a "blinded" manner clinically and histologically before resurfacing, immediately after resurfacing, 2 to 3 days postoperatively, 1 week postoperatively, and, 4 to 8 weeks postoperatively. RESULTS: There was slightly less inflammation with the CO2/Er:YAG-treated patients. The epidermis re-formed 1 to 2 days faster with combination (UPCO2)/Er:YAG treatment than with UPCO2 laser treatment alone. In 7 of 10 patients, Er:YAG erythema resolved within 2-3 weeks with CO2 x 3 erythema persisting at the 8-week follow-up period in all patients. Three of 10 patients had no difference in the degree of erythema between the 2 treatment areas. Clinical findings correlated with histologic findings of vascularity. There was no difference in the extent or time of edema between techniques. The usual demarcation line between cheek and neck at the mandibular angle was less apparent when the UPCO2/Er:YAG combination was used. Two of 10 patients noted quicker healing with the combination laser technique. CONCLUSION: Treating a patient with the Er:YAG laser after treatment with the UPCO2 laser results in a decreased incidence of adverse sequelae without a noticeable difference in the degree of wrinkle improvement.     

In vivo histological evaluation of a novel ablative fractional resurfacing device

BACKGROUND AND OBJECTIVES: A novel carbon dioxide (CO(2)) laser device employing ablative fractional resurfacing was tested on human skin in vivo for the first time. STUDY DESIGN/MATERIALS AND METHODS: An investigational 30 W, 10.6 microm CO(2) laser system was focused to a 1/e(2) spot size of 120 microm to generate an array of microscopic treatment zones (MTZ) in human forearm skin. A range of pulse energies between 5 and 40 mJ was tested and lesion dimensions were assessed histologically using hematoxylin and eosin. Wound healing of the MTZ's was assessed immediately-, 2-day, 7-day, 1-month, and 3-month post treatment. The role of heat shock proteins was examined by immunohistochemistry. RESULTS: The investigational CO(2) laser system created a microscopic pattern of ablative and thermal injury in human skin. The epidermis and part of the dermis demonstrated columns of thermal coagulation that surrounded tapering ablative zones lined by a thin eschar layer. Changing the pulse energy from 5 to 30 mJ resulted in a greater than threefold increase in lesion depth and twofold increase in width. Expression of heat shock protein (hsp)72 was detected as early as 2 days post-treatment and diminished significantly by 3 months. In contrast, increased expression of hsp47 was first detected at 7 days and persisted at 3 months post-treatment. CONCLUSION: The thermal effects of a novel investigational ablative CO(2) laser system utilizing fractional resurfacing were characterized in human forearm skin. We confirmed our previous ex vivo findings and show for the first time in-vivo, that a controlled array of microscopic treatment zones of ablation and coagulation could be deposited in human skin by varying treatment pulse energy. Immunohistochemical studies of heat shock proteins revealed a persistent collagen remodeling response lasting at least 3 months. We successfully demonstrated the first in-vivo use of ablative fractional resurfacing (AFR) treatment on human skin.     

The Effects of Variable Pulse Width of Er:YAG Laser on Facial Skin

BACKGROUND: The use of CO2 and Er:YAG lasers for resurfacing has increased significantly in the past few years. Er:YAG laser causes pinpoint bleeding during and after treatment with a typical pulse width of 250 microsec. A longer pulse of Er:YAG laser can potentially coagulate dermal blood vessels and increase the residual thermal damage (RTD). OBJECTIVE: To evaluate the effects of various pulse durations of Er:YAG laser on the depth of RTD and bleeding. METHODS: The preauricular skin of a volunteer was exposed to Er:YAG laser at 250-, 350-, and 700-microsec pulse durations, with a fluence of 5 J/cm2. The number of passes varied between 6 and 16. The treated skin was excised and a histologic evaluation was done. RESULTS: The maximum depth of RTD was 50 microm and there was decreased bleeding with a 700-microsec pulse duration. CONCLUSION: The increased pulse duration of Er:YAG laser of 700 micros does not increase the maximum reported RTD and therefore would not change the recovery time and may have a beneficial effect on hemostasis.     

Single-Pass Carbon Dioxide Versus Multiple-Pass Er:YAG Laser Skin Resurfacing: A Comparison of Postoperative Wound Healing and Side-Effect Rates

BACKGROUND: Ablative laser skin resurfacing with carbon dioxide (CO2) and erbium:yttrium-aluminum-garnet (Er:YAG) lasers has been popularized in recent years and their side effects individually reported. No prior study, however, has directly compared the relative healing times and complications rates between the two different systems. OBJECTIVE: To evaluate and compare postoperative wound healing and short- and long-term side effects of single-pass CO2 and multiple-pass, long-pulsed Er:YAG laser skin resurfacing for the treatment of facial photodamage and atrophic scars. METHODS: A retrospective chart review and analysis of sequential clinical photographs were performed in 100 consecutive patients who underwent laser skin resurfacing with single-pass CO2 (Ultrapulse 5000; Coherent, Palo Alto, CA, N=50) or multiple-pass, long-pulsed Er:YAG laser resurfacing (Contour; Sciton, Palo Alto, CA, N=50). All laser procedures were performed by a single operator for the amelioration of facial rhytides or atrophic scars. The rate of re-epithelialization, duration of erythema, and presence of complications were tabulated. RESULTS: The average time to re-epithelialization was 5.5 days with single-pass CO2 and 5.1 days with long-pulsed Er:YAG laser resurfacing. Postoperative erythema was observed in all patients, lasting an average of 4.5 weeks after single-pass CO2 laser treatment and 3.6 weeks after long-pulsed Er:YAG laser treatment. Hyperpigmentation was seen in 46% of the patients treated with single-pass CO2 and 42% of the patients treated with the long-pulsed Er:YAG laser (average duration of 12.7 and 11.4 weeks, respectively). No incidences of hypopigmentation or scarring were observed. CONCLUSION: Skin resurfacing with single-pass CO2 or multiple-pass long-pulsed Er:YAG laser techniques yielded comparable postoperative healing times and complication profiles.     

Use of a novel erbium laser in a Yucatan minipig: a study of residual thermal damage, ablation, and wound healing as a function of pulse duration

BACKGROUND AND OBJECTIVE: Theoretical models show that varying pulse duration influences residual thermal damage in erbium YAG skin resurfacing. Accordingly, our objective was to compare residual thermal damage, ablation, tissue shrinkage, and wound healing between a variable pulsewidth erbium YAG laser and a popular CO2 resurfacing laser. STUDY DESIGN/MATERIALS AND METHODS: The erbium laser delivered a typical ablative pulse (250 microseconds), followed by a heating pulse of variable duration. Pulse durations for specific coagulation depths were selected based on existing heat transfer models. The bilateral flanks of one Yucatan pig were irradiated. Eight sites were treated per group. Biopsies were performed just after treatment and 1, 3, 7, 21, and 60 days postoperatively. RESULTS: Just after irradiation, gross examination of "cold" (without a coagulation pulse) erbium sites showed a reddish papillary dermis consistent with conventional erbium laser ablation. Two and three pass CO2 sites showed uniform surface yellowing. The longer pulsewidth ("hot") erbium groups showed only slight surface yellowing. Biopsies showed immediate thermal damage that increased with erbium pulse duration; however, actual residual thermal damage (RTD) was sometimes less than that predicted by the laser control panel. All wounds healed uneventfully by 14 days. CONCLUSIONS: An erbium laser with a variable macropulse pulsewidth was capable of achieving RTD of up to 80 mum. Even greater RTD depths may be obtainable with future manipulations of fluence and pulse duration.     

Analysis of Erythema after Er:YAG Laser Skin Resurfacing

BACKGROUND Postoperative erythema can be expected to occur in every patient after laser resurfacing, and pigmentary disturbances may be related to the intensity and the duration of erythema.
OBJECTIVE This study was undertaken to assess the clinical features of erythema, the factors that influence its duration, and the relation between the duration of erythema and the incidence of hyperpigmentation and hypopigmentation in skin of Asian persons after Er:YAG laser resurfacing.
METHODS A total of 218 patients (skin phototypes III to V) were recruited and treated with a short-pulsed Er:YAG laser, a variable-pulsed Er:YAG laser, or a dual-mode Er:YAG laser for skin resurfacing. Clinical assessments were performed retrospectively using medical charts and serial photographs.
RESULTS Postoperative erythema was observed in all patients after Er:YAG laser resurfacing with a mean duration of 4.72 months. In 98.2% of patients, erythema faded completely within 12 months. Postinflammatory hyperpigmentation was observed in 38.1% of patients after Er:YAG laser resurfacing.
CONCLUSIONS Skin phototype, level of ablation, and depth of thermal damage caused by a long-pulsed laser appear to be important factors that affect the duration of erythema. Moreover, prolonged erythema was related to the risk of postinflammatory hyperpigmentation.     

Laser Resurfacing of the Neck with the Combined CO2/Er:YAG Laser

BACKGROUND: Several clinical studies on laser resurfacing on the neck have yielded variable results with adverse sequelae of hypopigmentation and scarring using the CO2 laser. The Er:YAG laser on the neck resulted in an improved appearance with no adverse sequelae. The combined CO2/Er:YAG laser is a laser that combines a low fluence CO2 laser with the Er:YAG laser in a near simultaneous beam. OBJECTIVE: To study the effects of the CO2/Er:YAG laser on the neck. The decreased nonspecific thermal damage of the CO2/Er:YAG laser should result in decreased postoperative erythema and improved wound healing. METHODS: Eleven patients were treated with the CO2/Er:YAG laser on the neck as well as the face at identical settings. The face was treated with four passes while the neck was treated with two passes. The patients were evaluated for the first 2 weeks then 3-6 months postoperatively. Patients were asked about treatment satisfaction and improvement in skin texture and color using a 25% scale. Skin texture and color, as well as improvement in wrinkling and adverse results were judged by a dermatologist using a 0-4 scale. RESULTS: Moderate improvement was seen in skin color while a higher degree of improvement was seen in skin texture and wrinkling in all 11 patients. No adverse sequelae, including hypopigmentation or scarring, were observed. The majority of patients had a 75-100% improvement in skin texture and color in addition to a 75-100% overall satisfaction rating. CONCLUSIONS: There is a higher degree of overall patient satisfaction, as well as improvement in skin texture and skin color, compared to patients treated with the Er:YAG laser alone. The CO2/Er:YAG laser is a highly effective laser for neck resurfacing with no adverse sequelae to date.     

One-Pass CO2 Versus Multiple-Pass Er:YAG Laser Resurfacing in the Treatment of Rhytides: A Comparison Side-by-Side Study of Pulsed CO2 and Er:YAG Lasers

BACKGROUND: The CO2 laser is normally described as an aggressive resurfacing tool, whereas the erbium:YAG laser has enjoyed a reputation as the ideal tool for superficial resurfacing. The implication from many studies is that the CO2 laser is incapable of "minimally invasive" resurfacing. OBJECTIVE: To compare a short-pulsed CO2 laser with an Er:YAG laser over a range of parameters intended to produce equivalent microscopic and clinical injuries. METHODS: A prospective, randomized, comparative interventional trial was conducted in a tertiary care teaching hospital. Thirteen patients with facial wrinkles were enrolled in the study. A side-by-side comparison was performed using periorbital and perioral regions as treatment sites. One side was treated with a pulsed CO2 laser and the other with an Er:YAG laser. Postauricular skin was treated in an identical fashion to the study sites and biopsied for microscopic analysis. The biopsies were obtained before treatment, immediately after treatment, and either 3 or 6 months after treatment to evaluate the acute level of injury and subsequent degree of fibroplasia. Photographs were taken at baseline, immediately after treatment, 1, 2, and 6 weeks, and 3 and 6 months after treatment. Nine physicians evaluated the photographs for erythema, pigmentation, and wrinkle improvement. RESULTS: Investigator assessment showed no statistically significant differences between the lasers with respect to hyperpigmentation and wrinkle reduction. There was less erythema at the CO2 laser-treated sites 2 weeks after treatment; the differences had resolved by 6 weeks after treatment. Histologic examination demonstrated equivalent dermal thermal injury on immediate postoperative biopsies and equivalent fibroplasia on subsequent biopsies. Both CO2 and Er:YAG laser-treated sites showed overall modest wrinkle improvement compared to the pretreatment photographs. CONCLUSION: When CO2 and Er:YAG lasers are used in a manner such that there are equivalent immediate postoperative histologic results, equivalent healing and cosmetic improvement occurs. One can use CO2 laser with one pass to mimic a moderately aggressive Er:YAG laser treatment.     

Facial rhytides—subsurfacing or resurfacing? A review

STUDY DESIGN/BACKGROUND AND OBJECTIVES: Currently, ablative laser therapy (with CO2/Er:YAG lasers) is considered an effective and promising method of skin rejuvenation. The induction of collagen synthesis was observed after treatments with the CO2 laser and with the long-pulsed Er:Yag laser. In past years, the undesirable side effects and risks of these methods have led to intensified research efforts in the fields of non-ablative facial rejuvenation as well as subsurfacing by means of non-ablative laser systems and intense pulsed light systems. The objective is to achieve selective, heat-induced denaturalization of dermal collagen that leads to subsequent reactive synthesis of neocollagen but does not damage the epidermis. This article reviews the use of different types of lasers and intense pulsed light sources for the non-ablative treatment of facial rhytides. RESULTS: The results of numerous clinical and histological investigations have recently indicated that these new technologies are successful. Some studies demonstrated remarkable effects with non-ablative systems; others, however, showed only limited cosmetic improvement or none at all. CONCLUSIONS: After critical review and assessment of current literature on the treatment of rhytides, we have found that non-ablative methods do not appear to be a comparable alternative to ablative skin resurfacing in terms of their efficacy and side effects.     

Modulating the Er:YAG laser

BACKGROUND AND OBJECTIVES: In the past 2 years, there has been some controversy about the optimal laser system, or combination of systems, for cutaneous resurfacing. Initially, it seemed that the Er:YAG laser would have significant advantages over the CO(2) laser. In practice, some of those who jumped early onto the Er:YAG bandwagon have been unimpressed with the degree of skin tightening that can be achieved with this system. Also, the excessive bleeding induced by the Er:YAG lasers prevented deeper vaporization. During the past 18 months, three new "modulated" Er:YAG lasers have been produced that are said to be able to achieve CO(2) laser-like effects, while maintaining the Er:YAG laser advantages. The purpose of this article is to examine these new systems and to discuss their potential benefits, if any, over the "conventional" Er:YAG lasers, and the CO(2) lasers. STUDY DESIGN/MATERIALS AND METHODS: The author has collected data from his own experience and that of his colleagues in the department of dermatology at University of California at San Francisco. The author has used all three types of modulated Er:YAG laser on patients presenting for cosmetic laser resurfacing and the treatment of many benign conditions over an 18-month period. RESULTS: All three modulated forms of Er:YAG lasers have been demonstrated to provide better coagulation than the conventional Er:YAG lasers. The Derma-K and the Contour Er:YAG lasers were able to induce tissue contraction/desiccation similar to the CO(2) laser. The author and his colleagues have induced only two cases of permanent hypopigmentation in over 50 cases during the past 18 months while using the Er:YAG laser, significantly less than might be expected with the CO(2) lasers. CONCLUSIONS: If a laser surgeon is happy with the results obtained with a high-energy, short-pulse CO(2) laser, then there seems little reason to consider changing to an Er:YAG laser. The modulated Er:YAG lasers have definite advantages over the conventional Er:YAG lasers. They exhibit better control of hemostasis and can ablate tissue to a greater depth than the conventional Er:YAG lasers. The Er:YAG lasers might induce less permanent hypopigmentation than the CO(2) lasers.