Comparative study of CO2- and Er:YAG laser ablation of multiple cutaneous neurofibromas in von Recklinghausen's disease

With a prevalence of 1 in 3,000 births, neurofibromatosis type 1 (NF1) is one of the most common genetic disorders and is characterized by an uninhibited expansion of neural tissue. Occasionally, severe deformities occur, but frequently considerable cosmetic disfigurement is caused by the development of hundreds of benign cutaneous neurofibromas. The objective of this study was to evaluate the erbium:yttrium–aluminium–garnet (Er:YAG) laser as a therapeutic option for the removal of multiple cutaneous neurofibromas. In this prospective, comparative, in vivo study, 15,580 neurofibromas (44 operations on 21 patients) were removed via electrosurgery, CO₂- or Er:YAG laser ablation. In 12 adjacent test areas, we compared the zone of thermal necrosis, the postoperative pain, the time to reepithelialization, the duration of postoperative erythema and the cosmetic outcome of these surgical methods. When compared to electrosurgery and CO₂ laser ablation, the Er:YAG laser ablation outperformed the other methods of tumor removal. Rapid healing by second intention as well as the minimal discomfort and scar formation following Er:YAG laser ablation were noted. After 36 months of follow-up, permanent dyspigmentation was rare and hypertrophic scarring was not observed. Er:YAG laser vaporization of multiple cutaneous neurofibromas is a simple and rapid procedure that results in significantly better cosmetic results than CO₂ laser treatment or electrosurgery.     

Combination treatment utilizing fractional ablative and continuous wave CO2 lasers for hypertrophic burn scars

BackgroundHypertrophic scars are devastating outcomes of severe burn injuries, producing physical and mental burdens. Adequate treatment is of benefit to relieve these burdens. Laser therapy has shown scar reducing effects. In this study, we compared outcomes after combination of two different lasers or single laser treatment to treat severe hypertrophic burn scars.MethodsForty patients with hypertrophic burn scars were included in one of two therapeutic groups: continuous wave CO₂ laser and fractional ablative CO₂ laser group (group 1, n = 20) or fractional ablative CO₂ laser alone group (group 2, n = 20). Hypertrophic scars were evaluated by the observer-rated Vancouver Scar Scale (VSS) before and after treatment and by patient-completed questionnaires after treatment. Comparative analyses were performed before and after treatment, and time-dependent improvement was also analyzed.ResultsForty patients (54 hypertrophic scars) completed the laser treatment protocols. Group 1 exhibited significantly more improvement in VSS vascularity, pliability, and height indices than group 2 (p < 0.05). Time-dependent analysis of total VSS scores suggested that group 1 experienced more improvement during a shorter treatment period (p < 0.05). For patient-reported outcomes, group 1 noted better grades than group 2 in four indices, namely scar appearance, scar thickness, pain, and pruritus (p < 0.05).ConclusionEffective scar reduction was achieved using combination laser treatment, with significant improvement in multiple observer- and patient-reported outcomes. The shorter treatment period of the combination method can be a merit, as prolonged hypertrophic scars may increase morbidity. Nonetheless, cautious treatment protocols are necessary to avoid undesirable sequelae related to laser application.     

Effectiveness of artesunate combined with fractional CO2 laser in a hypertrophic scar model with underlying mechanism

Background and objectivesBoth artesunate and fractional CO₂ laser have been proved effective in the treatment of hypertrophic scars, yet little data are available for the efficacy of artesunate combined with fractional CO2 laser. In order to assess the pre-clinical significance and the underlying mechanism of this combined treatment profile, we attempted to observe the effectiveness of this therapy in rabbit models through determining the expression of BMP-7 and Fas.Materials and methodsTwenty-Four New Zealand white rabbits with established hypertrophic scar samples were randomly divided into control group and three treatment groups. Artesunate (20 μl/cm²) was injected into the rat’s scar of artesunate and combination groups, while fractional CO2 laser (Combo mode, deep energy:10 mJ, super energy: 50 mJ) was applied to rats in fractional CO2 laser and combination groups at week 4 after model establishment. All rabbits underwent a total of 3 sessions of treatment once every 2 weeks. Histological and immunohistochemistry study, Western blot assay, cell viability, ELISA and RT-QPCR were performed at week 10 to observe the aspects of hypertrophic scar sample changes and expression of BMP-7 and Fas in the scar tissues.ResultsCompared with control group, hypertrophic scars and the collagen fibers were significantly inhibited after treatment, and higher inhibition was seen in the samples in combination group compared to that in artesunate and fractional CO2 laser groups (P < 0.01). Meanwhile, BMP-7 and Fas expressions were both notably increased in all treatment groups, and upregulation of the two proteins was dominant in combination group (P < 0.01).ConclusionsArtesunate combined with fractional CO2 laser is effective in hypertrophic scarring in this rabbit model. Our findings can serve as a potential alternative strategy to treatment of hypertrophic scar in clinical practice.     

Efficacy and safety of fractional CO<Subscript>2</Subscript> laser versus fractional Er:YAG laser in the treatment of facial skin wrinkles

Ablative fractional lasers were introduced for treating facial rhytides. Few studies have compared fractional CO₂ and Er:YAG lasers on cutaneous photodamages by a split trial. The aim of the present study was to compare these modalities in a randomized controlled double-blind split-face design with multiple sessions and larger sample size compared to previous studies done before. Forty patients with facial wrinkles were enrolled. Patients were randomly assigned to receive three monthly treatments on each side of the face, one with a fractional CO₂ and one with a fractional Er:YAG laser. The evaluations included investigating clinical outcome determined by two independent dermatologists not enrolled in the treatment along with measuring skin biomechanical property of cheeks using a sensitive biometrologic device with the assessment of cutaneous resonance running time (CRRT). Moreover, possible side effects and patients’ satisfaction have been recorded at baseline, 1 month after each treatment, and 3 months after the last treatment session. Clinical assessment showed both modalities significantly reduce facial wrinkles (p value?<?0.05), with no appreciable difference between two lasers. Mean CRRT values also decreased significantly after the laser treatment compared to the baseline in both laser groups. There was no serious long-standing adverse effect after both laser treatments, but the discomfort was more pronounced by the participants after CO₂ laser treatment. According to the present study, both fractional CO₂ and fractional Er:YAG lasers show considerable clinical improvement of facial skin wrinkles with no serious adverse effects, but post-treatment discomfort seems to be lower with Er:YAG laser.     

Multiple laser pulses in conjunction with an optical clearing agent to improve the curative effect of cutaneous vascular lesions

Port-wine stain (PWS) birthmark is a congenital microvascular malformation of the skin. A 1064-nm Nd:YAG laser can achieve a deeper treatment, but the weak absorption by blood limits its clinical application. Multiple laser pulses (MLPs) are a potential solution to enhance the curative effect of a Nd:YAG laser. To reduce the pulse number (p_n) required for the thermal destruction of the blood vessel, the effect of glucose in conjunction with MLP was investigated. In vivo experiments were performed on a dorsal skin chamber model. Different concentrations (20, 25, 30, and 40%) of glucose were applied to the sub-dermal side of the hamster skin before laser irradiation. Identical vessels with diameters of 200?±?30 and 110?±?20 μm were chosen as representatives of typical PWS vessels. Instant thermal responses of the blood vessel were recorded by a high-speed camera. The required p_n for blood vessel damage was compared with that without glucose pretreatment. Results showed that the use of glucose with a concentration of 20% combined with MLP Nd:YAG laser to damage blood vessels is more appropriate because severe hemorrhage or carbonization easily appeared in blood vessels at higher glucose concentration of 25, 30, and 40%. When 20% glycerol is pretreated on the sub-dermal hamster skin, the required p_n for blood vessel damage can be significantly decreased for different power densities. For example, p_n can be reduced by 40% when the power density is 57 J/cm². In addition, generation of cavitation and bubbles in blood vessels is difficult upon pretreatment with glucose. The combination of glucose with MLP Nd:YAG laser could be an effective protocol for reducing the p_n required for blood vessel damage. Randomized controlled trial (RCT) and human trials will be conducted in the future.     

Early intervention by Z-plasty combined with fractional CO2 laser therapy as a potential treatment for hypertrophic burn scars

The aim of this study is to determine whether Z-plasty combined with fractional CO₂ laser therapy can be a potential management option for hypertrophic burn scars in the proliferation stage. A total of 105 patients (46 male and 59 female patients) diagnosed with hypertrophic scars under tension but without any functional limitations were enrolled in this study. The Vancouver Scar Scale (VSS) score and scar height were analyzed and compared. The VSS scores for all scars were improved in all groups after treatment. The scar height was also significantly decreased in each group after treatment (P < 0.05). In the C group, the scar height decreased significantly to 2.62 ± 0.21 mm, which was the maximum extent at the ≦ 6 month time point compared to the decrease in the other groups. Compared to the > 12 month time point for the C group, there was a significant difference between the ≦ 6 month time point for the L group and the > 12 month time point for the Z group. The proportion of satisfied patients was highest at 89.47% at the ≦6 month time point in the C group and lowest at 65.52% at the > 12 month time point in the L group. Six representative cases are presented. Z-plasty can decrease the thickness of a hypertrophic burn scar, which not only reduces the scar tension but also makes it easy to treat the scar with a fractional CO₂ laser. Subsequent treatment with a fractional CO₂ laser can better improve the color and texture of the scar.     

Transdermal delivery of three vitamin C derivatives by Er:YAG and carbon dioxide laser pretreatment

The objective of this study was to investigate the effects of two lasers (Er:YAG and CO₂) in enhancing skin permeation of three vitamin C derivatives, L-ascorbic acid 2-phosphate sesquimagnesium salt (MAP-1), magnesium L-ascorbic acid-2-phosphate (MAP-2), and 2-phospho-L-ascorbic acid trisodium salt (SAP). Dorsal skin of 1-week-old pathogen-free pigs was used for this in vitro study. Changes in permeation in laser-treated skin treated by the lasers were examined by confocal scanning electron microscopy. Transdermal flux of vitamin C derivatives was examined with a Franz diffusion cell. Fluxes of MAP-1, MAP-2, and SAP across Er:YAG laser-treated skin were 15–27-fold, 48–123-fold, and 22–56-fold higher, respectively, than their fluxes across intact skin. The fluxes of MAP-1, MAP-2, and SAP across CO₂ laser-treated skin were 28–36-fold, 116–156-fold, and 79–102-fold higher, respectively, than their fluxes across intact skin. Optimal fluency for the Er:YAG laser was 3.8 J/cm² for MAP-1 and 5 J/cm² for MAP-2 and SAP. Optimal fluency for the CO₂ laser was 5 W for all three derivatives. In conclusion, optimal fluency for all derivatives was 5 W for the CO₂ laser and 3.8 to 5 J/cm² for the Er:YAG laser.     

Vascular patterns in mature hypertrophic burn scars treated with fractional CO2 laser

Background and Objective

Fractional CO₂ laser has recently emerged as a promising therapeutic modality to improve the texture and appearance of burn scars. An issue in many burn scars is persistent erythema, which traditionally has been treated with vascular lasers. Interestingly, fractional CO₂ lasers have been shown to improve the appearance of burn scars, including erythema, but no mechanism has been proposed for this change. Our objective is to evaluate the histopathologic changes in vasculature in burn scars treated with fractionated CO₂ laser, and to attempt to describe the mechanism behind reduced erythema following treatment.

Study Design/Materials and Methods

Uncontrolled, prospective study of ten patients with mature burn scars, from a clinical and histological perspective. Biopsy specimens were obtained before and 2 months after 3 treatment sessions. Anti‐CD31 immunostaining was performed to highlight vascular patterns in biopsy specimens.

Results

In histological analysis, an increase in vascular density, particularly of small caliber vessels, was seen following treatment, with an 82.6% average increase in vasculature (P = 0.028). This increase in vascularity correlated with a decrease in clinical erythema and vascularity scores, measured using the Vancouver Scar Scale.

Conclusion

Mature hypertrophic burn scars treated with a fractional CO₂ laser showed a statistically significant increase in vascular density in the superficial dermis. A non‐statistical decrease in clinically perceived erythema and improvement of overall appearance was seen. To our knowledge, this is the first report of increased vascular density in burn scars treated with fractional CO₂ laser and suggests our prior assumptions on causes of erythema in mature hypertrophic scars may need to be challenged. Lasers Surg. Med. 46:597–600, 2014. © 2014 Wiley Periodicals, Inc.     

The effect of laparoscopic treatment of polycystic ovarian disease by CO2-laser or Nd:YAG laser

Summary The feasibility and efficacy of laparoscopic CO₂ laser and Nd:YAG non-contact laser application for the treatment of polycystic ovarian disease (PCOD) were evaluated in 30 patients (19 patients treated with the CO₂ laser, and 11 with the Nd:YAG laser). The criteria for inclusion of PCOD in our study were: amenorrhea or oligomenorrhea with chronic anovulation, failure to ovulate in response to clomide or human menopausal gonadotropin, elevated serum levels of luteinizing hormone (LH) or an elevated LH/follicle-stimulating hormone ratio, exaggerated LH response to gonadotrophin-releasing hormone (GnRH), elevated serum androgen levels, and ultrasonographic features of polycystic ovaries. Eight pregnancies after CO₂ laser and three after Nd:YAG laser were achieved. Decline of serum androgen concentrations was noted in both groups, but was significantly higher in the Nd:YAG laser group (from 3.4±0.4 ng/ml to 2.2±0.2 ng/ml). Nine patients checked before and after laser treatment showed a decrease in the characteristically exaggerated pituitary response to exogenous GnRH injection. There were no consistent findings of the pattern in LH pulsatility studied in 5 patients after Nd:YAG laser treatment. Ovarian status was investigated in 11 patients by second-look laparoscopy or cesarian section. There were absolutely no adhesions after Nd:YAG laser coagulation. Filmy adhesions were seen in 3 patients in the CO₂ laser group.     

Arthroscopic shoulder surgeyr with three different laser systems: An evaluation of laser applications

Twelve cadaveric shoulder arthroscopies were performed to evaluate the use of lasers as an adjunctive tool in arthroscopic shoulder surgery. The three most common lasers historically used in orthopedic surgery were examined: Holmium:YAG, Neodymium:YAG, and the CO₂. The following parameters were evaluated for each laser system: (1) each of use of the laser system and handpiece; (2) ability to excise and trim bursae, synovium, ligament, tendon, bone, and articular cartilage; and (3) ability to contract ligaments and capsule by heat transfer. None of these lasers efficiently cut bone, whereas all three systems readily debrided the soft tissues around the shoulder. The free-beam Ho:YAG and CO₂ systems heat contracted soft tissues with more control than the contact Nd:YAG. The fiberoptic delivery system of the Neodymium:YAG and Holmium:YAG laser performed well in the saline arthroscopy, and the CO₂ delivery system was cumbersome. Overall, the CO₂ system removed tissue better than the others, but its difficult use favored the Holmium laser as the best overall current laser system for shoulder arthroscopy.     

Carbon dioxide laser therapy of a widespread epidermal nevus

Background and Objective: The treatment of epidermal nevi is difficult and often unsatisfactory. Many therapeutic approaches have been tried, of which the surgical methods including lasers aim to avoid recurrences and hypertrophic scarring. Here we report the case of a widespread, life-impairing epidermal nevus, summarize the available treatment modalities, and discuss CO₂ laser therapy with respect to the clinically soft variants of these developmental defects. Study Design/Patients and Methods: A patient with a widespread, recurrent, biopsy-proven epidermal nevus was treated with a 10,600-nm CO₂ laser. After test treatments in local anaesthesia, four sessions were performed under general anaesthesia each with a follow-up time of 4 years to date. Results: CO₂ laser vaporization resulted in complete removal of the treated nevus without any obvious scarring. The patient is free of recurrence 4 years postoperatively. Conclusion. CO₂ laser treatment of epidermal nevi is a useful modality in selected variants. © 1995 Wiley-Liss, Inc.     

Nonablative Acne Scar Reduction after a Series of Treatments with a Short-Pulsed 1,064-nm Neodymium:YAG Laser

BACKGROUND: Effective treatment of facial acne scarring presents a major challenge. Nonablative lasers and radiofrequency devices work by thermally stimulating dermal collagen remodeling, thereby softening acne scars in a minimally invasive fashion. One such laser, a 1,064-nm short-pulsed Nd:YAG, uses rapidly scanned low-energy infrared pulses to heat the dermis selectively through the normal dermal microvasculature. OBJECTIVE: In this pilot study, the safety and efficacy of a novel short-pulsed Nd:YAG laser were investigated for the treatment of moderate to severe facial acne scarring. MATERIALS AND METHODS: Nine of 10 enrolled patients with moderate to severe facial acne scarring received eight sequential 1,064-nm Nd:YAG treatments (laser parameters 14 J/cm2, 0.3 milliseconds, 5-mm spot size, 7-Hz pulse rate, 2,000 pulses per side of face). Patients were graded for the presence and severity of three scar morphologies: superficial (rolling), medium-depth (boxcar), and deep (ice pick). Outcome measures included blinded evaluation of before and after photographs by three physician observers (scar severity score) and patient self-assessment. RESULTS: Acne scarring improved in 100% of the nine patients completing the study. Scar severity scores improved by a mean of 29.36% (95% confidence interval, 16.93%-41.79%; p = .006); 89% of patients noted greater than 10% scar improvement. No treatment-related adverse events were seen. CONCLUSION: Our findings support the use of a short-pulsed, low-fluence 1,064-nm Nd:YAG laser as a safe, effective treatment for facial acne scarring. Scar improvement was noted in all treated subjects with minimal discomfort and no downtime. This protocol appears to be most effective at reducing scar depth and softening scar contours. A laser upgrade needed for the study was provided to the authors at a reduced price.     

两种激光治疗中度寻常性痤疮对比研究

目的：观察比较1064nm Q开关脉冲激光、1320nm激光治疗中度寻常性痤疮的疗效及安全性,探索安全、有效的痤疮治疗方法。方法：对三组痤疮患者分别进行1064nm Q开关脉冲激光、1320nm激光以及口服美满霉素治疗,疗程为28天。结果：1064nm治疗组150例,共统计125例,有效率89.6%;1320nm组150例,共统计142例,有效率87.3%;美满霉素组60例,共统计55例,总有效率为89.1%。经统计学分析,三组疗效差异无统计学意义,且激光治疗副作用小。结论：两种激光治疗痤疮安全有效。     

Photoshop评价激光治疗痤疮凹陷性瘢痕疗效的探索

目的:探索Phot oshop在点阵Er:YAG激光治疗痤疮凹陷性瘢痕疗效分析中应用的可行性。方法:将点阵Er:YAG激光治疗痤疮凹陷性瘢痕患者的术前、术后照片输入计算机,并用Phot oshop CS5对每例患者正常部位及凹陷性瘢痕部位进行灰度值计算,然后计算激光术前灰度值差异率、激光术后灰度值差异率及凹陷性瘢痕改善率。结果:①激光术后灰度值差异率小于激光术前灰度值差异率,两组之间差异有显著性(P<0.05);②随着视觉评分的增高,凹陷性瘢痕灰度值改善率增加,评分为1分、2分组与评分为3分、4分组之间差异有显著性(P<0.05);③激光治疗次数为3次及3次以上组与治疗次数为2次及2次以下组凹陷性瘢痕灰度值改善率分别为3.3%及1.6%,但两组之间无显著性差异(P>0.05)。结论:①Phot oshop可以作为痤疮凹陷性瘢痕疗效性评价的客观评价方法;②点阵Er:YAG激光治疗痤疮凹陷性瘢痕有效。     

Skin pretreatment with lasers promotes the transdermal delivery of vitamin C derivatives

The objective of this study is to investigate the effects of two lasers (erbium:YAG and CO₂) on the ability to enhance skin permeation of two vitamin C derivatives, 3-O-ethyl ascorbic acid (EAC) and ascorbic acid 2-glucoside (AA2G). The study was taken in the skin of a female nude mouse (Balb/c-nu strain, 8 weeks old) in vitro. The histologic and ultrastructural changes of the nude mouse skin treated by the lasers were examined under light microscopy and transmission electron microscopy, respectively. The in vitro permeation of vitamin C derivatives was performed in Franz cell. The stratum corneum (SC) layer in the skin was partly ablated by erbium:YAG laser treatment, resulting in greater permeation of both vitamin C derivatives. The flux of EAC and AA2G across erbium:YAG laser-treated skin was 105 to 189-fold and 35 to 78-fold higher, respectively, than their flux across intact skin. The increase in enhancement ratio with increase in fluency decreases markedly for both compounds at the last dose escalation (from 5.0 to 6.3 J/cm²). Both SC ablation and a thermal effect may contribute to the effect of the CO₂ laser on skin structure. The flux of EAC and AA2G across CO₂ laser-treated skin was 181 to 277-fold and 82 to 117-fold higher, respectively, than their flux across intact skin. We concluded that both erbium:YAG and CO₂ laser pretreatment increased the transdermal flux of two stable vitamin C derivatives, EAC and AA2G. The optimal fluency for the Er:YAG laser was 5 J/cm².     

Experimental study of partial liver resection with a combined CO2 and Nd:YAG laser

The use of the CO₂ laser in liver surgery is mainly limited by the lack of coagulation of the larger vessels. In an experimental study, partial liver resections were performed on pigs with a Nd:YAG as well as with a combined CO₂ and Nd: YAG laser. The best cutting efficiency was obtained with the CO₂ laser. On the other hand, the Nd:YAG laser and the combined laser sources showed excellent hemostasis at the cutting edge corresponding with a width of necrosis at about 5 mm in histomorphometric examination and zones with histologically different characteristics. Rebleedings from the resection lines were avoided in all cases using the combined CO₂ and Nd:YAG laser.     

CO2 laser resurfacing of the face and neck.

Laser resurfacing with the short-pulsed, high-energy CO2 laser has been used to treat photodamaged skin and acne scars. Efficacy and safety have been demonstrated with this technique since 1992. Newer treatment methods, including sequential or combination treatment with the Er:YAG laser have led to increased efficacy with a decrease in adverse sequelae. This article details the author's experience with CO2 laser resurfacing and promotes the use of sequential CO2/Er:YAG laser resurfacing.     

Correlations between light penetration into skin and the therapeutic outcome following laser therapy of port-wine stains

. For several years the flashlamp-pumped pulsed dye laser (FPDL) has been the favoured method for the treatment of port-wine stains (PWS). The therapeutic outcome of FPDL laser therapy depends on the anatomical location of the PWS and is mainly attributed to morphological parameters such as size and depth of the PWS blood vessels. The aim of this study was to show a correlation between the therapeutic outcome following FPDL therapy and the optical properties of the skin overlying the PWS vessels. For this purpose the therapeutic outcome following FPDL treatment (585 nm; 0.45 ms) of 884 PWS situated on different body sites was evaluated by judging the grade of fading of PWS colour. On the other hand the light penetration into 123 skin samples (thickness 0.10–1.35 mm) was determined between 450 nm and 1030 nm and compared with the PWS laser therapy outcome for equal locations by statistical analysis. PWS on the neck, trunk, arms or legs yielded a higher mean grade of fading as compared to PWS on the head. Within the face, a wide range of fading was evident. The light penetration into skin increased linearly with increasing wavelength and location-dependent differences were found. The attenuation coefficient was 22.8±5.3 mm⁻¹ at 585 nm. No significant or strong correlation was observed between the therapeutic outcome of PWS laser therapy and the light penetration into skin. However, a correlation was obvious by plotting the respective profile plots. Therefore, among other effects, in particular morphological parameters of PWS vessels, the optical properties of the skin contribute to a small extent to the clinical outcome of PWS laser therapy. Paper received 2 May 2001; accepted after revision 21 June 2001.     

A randomized controlled clinical and histopathological trial comparing excisional biopsies of oral fibrous hyperplasias using CO<Subscript>2</Subscript> and Er:YAG laser

This study was conducted in order to compare clinical and histopathological outcomes for excisional biopsies when using pulsed CO₂ laser versus Er:YAG laser. Patients (n?=?32) with a fibrous hyperplasia in the buccal mucosa were randomly allocated to the CO₂ (140 Hz, 400 μs, 33 mJ) or the Er:YAG laser (35 Hz, 297 μs, 200 mJ) group. The duration of excision, intraoperative bleeding and methods to stop the bleeding, postoperative pain (VAS; ranging 0–100), the use of analgesics, and the width of the thermal damage zone (μm) were recorded and compared between the two groups. The median duration of the intervention was 209 s, and there was no significant difference between the two methods. Intraoperative bleeding occurred in 100% of the excisions with Er:YAG and 56% with CO₂ laser (p?=?0.007). The median thermal damage zone was 74.9 μm for CO₂ and 34.0 μm for Er:YAG laser (p?<?0.0001). The median VAS score on the evening after surgery was 5 for the CO₂ laser and 3 for the Er:YAG group. To excise oral soft tissue lesions, CO₂ and Er:YAG lasers are both valuable tools with a short time of intervention and postoperative low pain. More bleeding occurs with the Er:YAG than CO₂ laser, but the lower thermal effect of Er:YAG laser seems advantageous for histopathological evaluation.