Both the flashlamp-pumped dye laser and the long-pulsed tunable dye laser can improve results in port-wine stain therapy

BACKGROUND: At present, laser therapy of port-wine stains (PWS) using the flashlamp-pumped dye laser (FPDL) at 450 micros is accepted as the optimal approach. A few years ago, a new long-pulsed tunable dye laser (LPTDL, 1.5 ms) was introduced for the treatment of leg veins. OBJECTIVES: To investigate the efficacy and side-effects of FPDL vs. LPTDL therapy of PWS. METHODS: Sixty-two patients with untreated PWS underwent test treatments with the FPDL (585 nm; 7-mm spot size; 5.75--7.0 J cm(-2) fluence) and LPTDL (585, 590, 595, 600 nm; 5-mm spot size; 11--20 J cm(-2) fluence). With the LPTDL, the epidermis was additionally cooled (Spray cooling device). The fading was evaluated clinically 6 weeks after the test treatments. RESULTS: Optimal fading was achieved by the LPTDL (> or = 585 nm) in 30 patients and by the FPDL in 12 patients. No difference was found in 20 patients. At 585 nm, the lasers worked equally well in 12 (FPDL) and 13 (LPTDL) patients, respectively. Results were independent of the localization of the PWS and of the patient's age. In spite of the longer pulse duration, the LPTDL treatment did not result in more side-effects as long as sufficient cooling was provided. CONCLUSIONS: The results provide evidence that wavelengths longer than 585 nm can increase the efficacy of treatment in some PWS. Owing to the reduced light absorption by haemoglobin at longer wavelengths and consequently increased depth of the vascular injury, larger vessels can be damaged more adequately using an increased fluence. The LPTDL at 585 nm seemed to be slightly superior to the FPDL, while accepting that due to technical reasons the laser parameters were not directly comparable. Availability of both lasers increases the therapeutic possibilities in PWS.     

Results and tissue healing after copper-vapour laser (at 578 nm) treatment of port wine stains and facial telangiectasias

Twenty-four patients with port wine stains (PWS), and 33 patients with facial telangiectasias were treated with a copper-vapour laser (CVL) operating at 578 nm. Good to excellent results were obtained in 52% of PWS and 69% of facial teiangiectasias. Enzyme histochemistry revealed vessel-selective damage with energy densities up to 12 J/cm², but a non-specific coagulation necrosis with higher fluences (≥ 15 J/cm²). With vessel-selective fluences only moderate blanching was obtained in two PWS. All other evaluated patients were treated using non-selective energy densities. Tissue healing was comparable with that after argon laser treatment. The theoretically correct wavelength (578 nm) alone appeared to be no guarantee of vessel-selective damage. The laser employed laeked adequate power (only 1.3 W maximum) to transmit sufficient energy into the tissues in a short exposure time. However, the clinical results confirm the value of the CVL in the treatment of superficial cutaneous angiodysplasias.     

A comparative study of a 595-nm with a 585-nm pulsed dye laser in refractory port wine stains

BACKGROUND: The pulsed dye laser (PDL) is the treatment of choice for port wine stains (PWS); however, some patients' PWS become refractory to further treatments. Technological advances have enabled new machines with the advent of surface cooling devices to deliver longer wavelengths and higher fluence more safely. These advances have the potential to achieve improved response rates in refractory PWS. There are few studies comparing the efficacy of standard PDL treatments for refractory PWS with the wider choice of treatment variables available from newer PDL machines. OBJECTIVES: To determine if there is any advantage of using a longer wavelength (595 nm) and pulse widths (1.5 ms, 6 ms and 20 ms) over conventional PDL settings (wavelength 585 nm, pulse width 1.5 ms) in refractory PWS. METHODS: Eighteen consecutive consenting patients with Fitzpatrick skin types 1-4 with a mean age 35 years (range 17-59 years) with refractory PWS were treated routinely with three separate test areas using 595-nm PDL (using three different pulse width settings of 1.5 ms, 6 ms and 20 ms), compared with test areas treated with 585-nm PDL (pulse width 1.5 ms). All test areas were treated with an identical fluence (15 J cm(-2)), spot size (7 mm) and cooling setting (dynamic cooling 60 ms, delay 60 ms). RESULTS: We found a statistically significant advantage of 595-nm PDL (pulse width 1.5 ms) over 595-nm PDL (pulse width 6 ms) (P < 0.05) in the treatment of refractory PWS; however, we found no significant advantage using longer pulse widths of 20 ms compared with 1.5 ms with the 595-nm PDL. There was no statistically significant advantage in using a 595-nm PDL over a 585-nm PDL using identical pulse widths of 1.5 ms, spot size, fluence and cryogen cooling settings; however, the number of directly comparable test areas was smaller. Some individual patients in our study obtained a better response with certain 595-nm PDL settings (pulse width 1.5 ms and 6 ms) compared with 585-nm PDL (pulse width 1.5 ms). CONCLUSIONS: Our experience of high fluence PDL in the treatment of refractory PWS suggests patients treated with 585 nm (pulse width 1.5 ms) improve to a similar degree as patients treated with 595-nm PDL (pulse width 1.5 ms). However, the use of the 595-nm PDL with longer pulse widths yields no extra advantage. For those patients who have failed to improve with high-fluence 585-nm PDL (pulse width 1.5 ms), test areas using 595-nm PDL (pulse width 1.5 ms and 6 ms) should be undertaken to ascertain if individual patients may benefit from the longer pulse width 595-nm PDL.     

Potassium titanyl phosphate laser treatment of resistant port-wine stains

BACKGROUND: The pulsed dye laser (PDL; 585 nm, 450 micros pulse) has been established as the treatment of choice for port-wine stains (PWS), but only few patients have total clearance. A modulated potassium titanyl phosphate (KTP) laser (532 nm) has been developed that allows the adjustment of energy fluences within the 5-50 J cm-2 range with laser pulse widths between 1 and 50 ms at pulse rates from 1 to 20 pulses s(-1). OBJECTIVES: To determine the efficacy and side-effect rate of the KTP laser in treating PDL-resistant PWS. METHODS: Thirty patients were recruited. The site and colour of the PWS were recorded and assessed with erythemameter readings, videomicroscopy and photography both before and after treatment. All patients had test areas treated on their first visit and were then reviewed at 2-monthly intervals. Repeat treatments were given if no adverse effects had occurred and if the treated areas had shown between 25 and 100% lightening. RESULTS: Thirty patients were assessed, age range 11-63 years (mean 35.4) with 19 females. The PWS affected the face in 21 (70%) patients, leg in five (17%) and other sites in four (13%). Patients had one to four tests or treatments (mean 2.2) with the KTP laser. Overall, 16 (53%) patients showed > 25% response and five (17%) showed > 50% response to treatments with the KTP laser. Best responses were found with fluences ranging from 18 to 24 J cm(-2) with pulse width 9-14 ms. No correlation was found with the colour of the PWS or the number of previous treatments with PDL. Patients preferred the KTP laser treatments compared with the PDL (visual analogue score mean 9.8; n = 5) with less discomfort during treatments and minimal purpura post-treatment. Six patients (20%) developed side-effects: scarring (n = 2, 7%), hyperpigmentation (n = 3, 10%) and prolonged healing phase of over 4 weeks (n = 1, 3%). CONCLUSIONS: We have shown that the KTP laser can further lighten PDL-resistant PWS and that it is a useful addition to the laser treatment of PWS. Further studies need to assess the efficacy and side-effects of the KTP laser in previously untreated PWS.     

Copper vapour laser treatment of port wine stains: clinical evaluation and comparison with conventional argon laser therapy

The copper vapour laser (CVL), emitting at 578 nm. offers potential advantages over the argon laser in the treatment of port wine stains (PWS). In this study, two test areas were performed with each laser using a Hexascan delivery system in 31 patients with PWS. One area was treated at minimal blanching fluence and one at 75% of this fluence. The pulse width was constant for each patient (mean 155 ms). Four-month assessments were made using a fading scale of 0–4. and objectively by an index of light absorbence using reflectance spectrophotometry. The CVL-treated sites had significantly better fading scores than argon laser-treated sites at minimal blanching fluence (P<0.005) and lower absorbence indices (P<0.05). Fading was significantly greater at minimal blanching fluence than at 75% of this fluence by fading scores and absorbence index values for both lasers. Slight textural and pigmentary changes were seen in a smafl minority of both CVL and argon tests at minimal blanching fluence only. This study indicates that the CVL is superior to the argon laser in treatment of predominantly red-purple or purple PWS. The minimal blanching technique produces greater fading than a lower energy fluence.     

Copper vapour laser (578 nm) and flashlamp-pumped pulsed tunable dye laser (585 nm) treatment of port wine stains: results of a comparative study using test sites

The copper vapour laser (CVL), emitting at 578 nm, has recently become available for treating vascular skin lesions. Its place in the management of port wine stains (PWS) requires clarification. We have compared a CVL with a pulsed tunable dye laser (PTDL; 585 nm) in 43 patients with macular, blanchable PWS. Test areas were performed with the CVL, using a Hexascan and an energy fluence just sufficient to produce immediate tissue change (mean fluence 18.2J/cm² and mean pulse width 50 ms). Test areas were performed with the PTDL using a 5-mm spot at 6.5 J/cm². Assessments were made after 4 months, subjectively using a clinical fading score and objectively using an index of light absorbence derived from reflectance spectrophotometry. The fading produced by the PTDL was significantly better than the CVL, as determined by clinical assessment (mean fading scores 2.41 and 1.67, respectively, P<0.0005) and reflectance spectrophotometry (mean absorbence index 149 and 157 respectively, P<0.0005). These results indicate that the PTDL is the preferred treatment for most macular, blanchable PWS. However, in a proportion of lesions responses were equivalent with both lasers, and in a small proportion, the CVL produced a better response.     

595nm脉冲染料激光与1064nm长脉宽Nd-YAG激光治疗鲜红斑痣疗效对比

目的回顾性分析比较595 nm脉冲染料激光及1 064 nm长脉宽Nd-YAG激光治疗鲜红斑痣的疗效及不良反应。方法应用595 nm脉冲染料激光(能量为8~15 J/cm^2,脉宽为1.5~10 ms)及1 064 nm Nd-YAG激光(能量密度为120~130 J/cm^2,脉宽25~45 ms)共治疗鲜红斑痣1 150例,从年龄、性别、皮损类型、不同治疗次数及不良反应等方面比较2种激光的疗效。结果 595 nm激光与1 064 nm Nd-YAG激光治疗鲜红斑痣有总效率分别为70.33%、76.99%,差异有统计学意义(χ~2=6.58,P<0.05);尤其是增厚型皮损,有效率分别为23.08%、58.47%,差异有统计学意义(χ~2=23.84,P<0.01);瘢痕发生率分别为0.37%、3.48%,差异有统计学意义(χ~2=14.16,P<0.01)。结论 595 nm脉冲染料激光及1 064 nm Nd-YAG激光治疗鲜红斑痣均安全有效,后者疗效略高于前者,但瘢痕发生率也略高。     

Selective photothermolysis: contribution to the treatment of flat angiomas (port wine stains) by laser

Since 1962, lasers have been used in dermatology and have become the first choice in the treatment of superficial, vascular ectasia. Lasers are unique sources of light; they are coherent, monochromatic, collimated and intense. By careful selection of wavelength, pulse duration, and intensity, it is often possible to selectively confine a laser effect to a specific histologic structure in tissue, depending upon the tissue properties. The ideal treatment of Port Wine Stains (PWS) should irreversibly damage the ectatic vessels but minimize heating of the epidermis and superficial dermis. A theory, called selective photothermolysis, predicts the optimal combination of laser parameters of achieving this ideal treatment of PWS to be a wavelength of 577 nm, a pulse duration of 0.35-10 msec, and an energy per surface area of about 7-8 J/cm2. Laser wavelength: The wavelength of 577 nm is preferred because it: maximizes the selective absorption by hemoglobin, minimizes absorption by epidermal melanin, provides sufficient depth of penetration in the blood to coagulate 0.1 mm vessels allows penetration of light into dermis up to 1 mm. Laser pulse duration: A pulse-width in the range of 0.35-10 msec allows the temperature elevation to be uniform inside the vessel and to be confined to the vessel area. Shorter pulses superheat the red blood cells causing explosive boiling and hemorrhage. Longer pulses allow heat to diffuse away from vessels, requiring greater energies per pulse to achieve vessel damage. An increased energy per pulse increases the risk of excessive damage to surrounding tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of fluence and pulse-duration on purpuric threshold using an extended pulse pulsed-dye laser in the treatment of port wine stains

Laser therapy of port-wine stains (PWS) using the extended pulse pulsed-dye laser (EPPDL) is accepted as the optimal approach because the thermal relaxation time for the vessels in PWS is actually 1-10 msec. The purpose of this study is to elucidate the purpuric threshold using the EPPDL for treatment of PWS. One hundred and seventy-seven Japanese patients with PWS were recruited for this study. All the patients were dark-skinned with skin phototype III (n = 103) and IV (n = 74). PWS were treated with the EPPDL with a pulse duration ranging 1.5-10 msec, fluence ranging 9-15 J/cm(2), and a spot size of 7 mm. Cryogen spray cooling (CSC) was fixed to 30 msec of delay and 30 msec of spray duration. Patients returned to our clinic within 1 week after their initial laser therapy and the treatment sites were examined for the evidence of purpura formation. Of the 177 patients, 108 developed purpura. The lowest fluences that caused purpura and were seen in more than 50% of patients were 10 J/cm(2) with a pulse duration of 1.5 msec, 12 J/cm(2) with a pulse duration of 3 msec, 13 J/cm(2) with a pulse duration of 6 msec, and 13 J/cm(2) with a pulse duration of 10 msec. The fluence and pulse duration thresholds were 12.5 J/cm(2) and 1.65 msec, respectively. Because purpura is one of the treatment endpoints when using a pulsed-dye laser for PWS, higher fluences are necessary when using a long pulse duration.     

Effects of cryogen spray cooling and high radiant exposures on selective vascular injury during laser irradiation of human skin

BACKGROUND: Increasing radiant exposure offers a means to increase treatment efficacy during laser-mediated treatment of vascular lesions, such as port-wine stains; however, excessive radiant exposure decreases selective vascular injury due to increased heat generation within the epidermis and collateral damage to perivascular collagen. OBJECTIVE: To determine if cryogen spray cooling could be used to maintain selective vascular injury (ie, prevent epidermal and perivascular collagen damage) when using high radiant exposures (16-30 J/cm2). DESIGN: Observational study. SETTING: Academic hospital and research laboratory. PATIENTS: Twenty women with normal abdominal skin (skin phototypes I-VI). INTERVENTIONS: Skin was irradiated with a pulsed dye laser (wavelength = 585 nm; pulse duration = 1.5 milliseconds; 5-mm-diameter spot) using various radiant exposures (8-30 J/cm2) without and with cryogen spray cooling (50- to 300-millisecond cryogen spurts). MAIN OUTCOME MEASURE: Hematoxylin-eosin-stained histologic sections from each irradiated site were examined for the degree of epidermal damage, maximum depth of red blood cell coagulation, and percentage of vessels containing perivascular collagen coagulation. RESULTS: Long cryogen spurt durations (>200 milliseconds) protected the epidermis in light-skinned individuals (skin phototypes I-IV) at the highest radiant exposure (30 J/cm2); however, epidermal protection could not be achieved in dark-skinned individuals (skin phototypes V-VI) even at the lowest radiant exposure (8 J/cm2). The red blood cell coagulation depth increased with increasing radiant exposure (to >2.5 mm for skin phototypes I-IV and to approximately 1.2 mm for skin phototypes V-VI). In addition, long cryogen spurt durations (>200 milliseconds) prevented perivascular collagen coagulation in all skin types. CONCLUSIONS: Cryogen spurt durations much longer than those currently used in therapy (>200 milliseconds) may be clinically useful for protecting the epidermis and perivascular tissues when using high radiant exposures during cutaneous laser therapies. Additional studies are necessary to prove clinical safety of these protocols.     

Treatment of port wine stains using the pulsed-dye laser at 585 nm with the dynamic cooling device

Port wine stains (PWS) are common vascular malformations appearing more frequently on the face and neck. One of the most prevalent treatment modalities for PWS is the pulsed-dye laser (PDL). The first generation PDL was limited to a 450 &#119 s pulse width which was inadequate for the treatment of larger caliber vessels. Second generation PDLs have pulsed widths approximately three times longer (1.5 ms). This, along with the dynamic cooling device (DCD), which allows the safe use of higher fluences, should result in more clinical improvement in the treatment of PWS that were previously resistant or minimally responsive to first generation PDL treatment. We report a case of a 29-year-old white male with extensive PWS on the left face, left neck, and back, which displayed only mild changes with the first generation PDL. However, the use of the 1.5 ms PDL at 585 nm at high fluences in conjunction with the DCD resulted in marked improvement of the patient's PWS.     

(18) The treatment of portwine stains with the tunable dye laser at 577 nm

The treatment of portwine stains (PWS) by lasers has become established as the treatment of choice in recent years. Most experience has been with the argon laser which emits predominantly at 488 and 514 nm. These wavelengths do not coincide with the absorption maxima of haemoglobin at 415, 542 and 577 nm. Light at 577 nm is particularly well transmitted through the epidermis and selectively absorbed by haemoglobin. We have been treating patients with PWS with a Coherent CR599 argon-pumped continuous wave tunable dye laser emitting at 577 nm.
Seventy-one patients with PWS have been treated in Leeds, mean age 36·9 years, range 11–61 years. Ninety-six per cent had PWS on the face or neck. The majority were treated under local anaesthesia; the longest follow-up has been 42 months.
The minimal blanching method was used¹ with a spot diameter of 1 mm, power range of 0·3 – 0·5 W in most patients, with a pulse duration of 0·5–2 s. Energy fluence was 38–63 J/cm².
Improvement in the treated area from partial to complete paling occurred in 75% with scarring in 5% which was usually atrophic, and minor pigmentary changes in 7%.
These results are comparable with the best series reported from argon laser therapy and confirm the theoretical advantage of treatment with laser light at 577 nm.     

Does dye laser treatment with higher fluences in combination with cold air cooling improve the results of port‐wine stains?

BACKGROUND AND OBJECTIVE: The use of cold air cooling (CAC) and cryogen spray cooling during dye laser treatment of port-wine stains (PWS) has become a standard in recent years. Still unsolved is the question of which fluences are necessary in combination with CAC in order to achieve an optimum clearance and the lowest possible rate of side-effects. STUDY DESIGN: In a prospective study, we treated 11 patients with PWS with pulsed dye laser (Photogenica V, Cynosure, lambda = 585 nm, iota(p) = 0.5 ms, spot size = 7 mm). Each PWS was partitioned into three areas: (area 1) 6 J/cm(2) without CAC, (area 2) 6 J/cm(2) with CAC (level 4), (area 3) 9 J/cm(2) with CAC (level 4). RESULTS: Area 3 (mean, 59%) showed a slightly better clearance than area 1 (mean, 57%); in area 2, we observed a reduced clearance (mean, 45%). Compared with area 1, we achieved a reduction of pain through CAC in areas 2 and 3. The healing periods as well as the rate of side-effects were comparable in all areas. CONCLUSION: We observed a slight but not statistically relevant increase in clearance with the use of higher fluences and CAC compared with lower fluences without CAC. Because pain is lowered significantly when using CAC, and because this makes the treatment more comfortable for the patients, we tend to recommend the use of higher fluences (9 J/cm(2)) with simultaneous CAC for treating PWS.     

Nd:YAG 1064nm激光治疗鲜红斑痣动物模型的研究

目的 通过动物模型观察可调脉宽Nd:YAG 1064 nm激光对鲜红斑痣的治疗作用。方法 以10只莱亨鸡鸡冠作为鲜红斑痣动物模型,随机分为5组,每组2只,其中1组作为空白对照不给予照射,其余各组分别以90、100、110、120 J/cm²能量密度照射,脉宽11.5 ms,光斑直径均为6 mm,每只鸡鸡冠照射四个区域。分别观察照射后鸡冠形态学和组织学的变化,并对照射前后每高倍镜下血管数的变化进行统计学分析。结果 经1次照射,鸡冠被照射区域颜色变淡,光镜下可见真皮的血管层变薄,血管闭锁,血管数目减少,腔内少量或无红细胞。与照射前比较,照射后血管数有明显减少(P<0.05),在一定范围内,能量越高,变化越明显。结论 可调脉宽Nd:YAG 1064 nm脉冲激光可以引起真皮血管闭锁,血管减少,血管层变薄,从而达到对鲜红斑痣的治疗作用。     

Variable pulse frequency-doubled Nd:YAG laser versus flashlamp-pumped pulsed dye laser in the treatment of port wine stains

The flashlamp-pumped pulsed dye laser (FPDL) is regarded as the gold standard in the treatment of port wine stains. The purpose of this prospective, intra-individual, comparative clinical study was to investigate whether a frequency-doubled variable pulsed Nd:YAG laser (frequency-doubled Nd:YAG) is equally as safe and effective as established lasers. Forty-three patients with port wine stains were included in the study. Test treatments were performed using the frequency-doubled Nd:YAG laser (532 nm; 4 mm psi; 5-50 ms; 5.5 to 15 J/cm2) versus the FPDL (585 nm; 450 micros; 7 mm psi; 6 J/cm2). After 6 weeks, a full lesional treatment was performed using the device and the parameters showing the best clearance and the fewest side effects. The clearance of the lesions was generally good to fair. With the exception of poor results at 5 ms and 5.5 J/cm2 with the frequency-doubled Nd:YAG laser, there were no significant differences between the two laser devices. Scar formation, nevertheless, occurred in only 3% of the FPDL-treated sites versus up to 18% of the frequency-doubled Nd:YAG sites, increasing with pulse duration. In port wine stains, the FPDL remains the therapy of choice because of the somewhat better results and a lower frequency of side effects, especially scarring.     

Selective photothermolysis of blood vessels following flashlamp-pumped pulsed dye laser irradiation: in vivo results and mathematical modelling are in agreement

Laser therapy using the pulsed dye laser is the standard treatment for port-wine stains (PWS). But the mechanism of action has not been elucidated completely, yet. The dorsal skin-fold chamber model in hamsters was used to investigate the effects of laser treatment (lambda(em)=585 nm; pulse duration: 0.45 ms; fluence: 6 J per cm2) on blood vessels. Vessels (n=3394) were marked with FITC dextran (MW 150 kDa) and diameters (2-186 microm) were measured using intravital fluorescence microscopy up to 24 h following irradiation. Histology (H&E, TUNEL, CD31) was taken 1 or 24 h after irradiation. The experimental results were compared with the predictions of a mathematical model based on the finite-element method. Following irradiation treatment the number of unperfused vessels decreases with decreasing vessel diameter in vivo. Histology indicated a restriction of tissue injury to the irradiated area after 1 h. Blood vessels contained aggregated red blood cells. After 24 h tissue damage occurred also outside the irradiated area and thrombus formation was visible. These results were in agreement with the mathematical calculations. In addition to initial physical effects after pulsed dye laser treatment delayed biological processes contribute significantly to the reduction of perfused blood vessels. Because of incomplete photocoagulation of smaller blood vessels (diameter 2-16 microm) a complete bleaching of PWS seems to be unlikely.     

Q-switched ruby laser irradiation of normal human skin. Histologic and ultrastructural findings.

The Q-switched ruby laser is used for treatment of tatoos. The effects of Q-switched ruby laser pulses on sun-exposed and sun-protected human skin, as well as senile lentigines, were investigated with clinical observation, light microscopy, and transmission electron microscopy. A pinpricklike sensation occurred at radiant exposures as low as 0.2 J/cm2. Immediate erythema, delayed edema, and immediate whitening occurred with increasing radiant exposure. The threshold for immediate whitening varied inversely with skin pigmentation, ranging from a mean of 1.4 J/cm2 in lentigines to 3.1 J/cm2 in sun-protected skin. Transmission electron microscopy showed immediate alteration of mature melanosomes and nuclei within keratinocytes and melanocytes, but stage I and II melanosomes were unaffected. Histologically, immediate injury was confined to the epidermis. There was minimal inflammatory response 1 day after exposure. After 1 week, subthreshold exposures induced hyperpigmentation, with epidermal hyperplasia and increased melanin staining noted histologically. At higher radiant exposures, hypopigmentation occurred with desquamation of a pigmented scale/crust. All sites returned to normal skin color and texture without scarring within 3 to 6 months. These observations suggest that the human skin response to selective photothermolysis of pigmented cells is similar to that reported in animal models, including low radiant exposure stimulation of melanogenesis and high radiant exposure lethal injury to pigmented epidermal cells.     

Flashlamp pulsed dye laser and argon-pumped dye laser in the treatment of port-wine stains: a clinical and histological comparison

BACKGROUND: Port-wine stains (PWS) are congenital vascular malformations occurring in 0.3% of children. The pulsed dye laser is a well established treatment for PWS. OBJECTIVES: To compare, clinically and histologically, the effects of the flashlamp pulsed dye laser with the argon-pumped dye laser in the treatment of PWS. METHODS: Thirty patients were treated on two to four test areas with both laser types using different energy fluences. A flashlamp pulsed dye laser with 0.45 ms pulse duration and a spot size of 5 mm was compared with an argon-pumped dye laser, with a spot size of 1 mm delivered with a robotic scanning laser handpiece (Hexascan) and 70-190 ms pulse duration. Both were tuned to 585 nm. Twelve weeks later the degree of lightening was evaluated and biopsies were taken. To count the vessels the skin sections were stained with CD34 using an immunohistochemical technique. The vessels were divided into three groups by diameter (d): d < 10 microm, 10 < or = d < 20 microm, d > or = 20 microm. RESULTS: The clinical results showed a significantly better lightening using the flashlamp pulsed dye laser than with the argon-pumped dye laser. The histological results showed a significant decrease in the number of vessels of diameter larger than 20 microm in treated compared with untreated lesions. We found no histological difference in the number of vessels between the two laser treatments. However, there was a tendency towards more small vessels (diameter < 10 microm) after one treatment with the flashlamp pulsed dye laser compared with untreated PWS. CONCLUSIONS: The flashlamp pulsed dye laser is clinically superior to the argon-pumped dye laser in the treatment of PWS.     

Treatment technics in argon laser therapy

This study compares 50 msec and 200 msec laser pulses with continuous application of the argon laser to test sites within port-wine stains (PWS). It also assesses the effects of different irradiance, energy fluence, and spatial average energy fluence on PWS lightening. Test areas responded with diminution of lesional color and lack of scarring as well as or better than to laser treatment by continuous exposure. Despite differences in irradiance and energy fluence for each laser impulse, the total energy delivered to all test areas was similar. There appeared to be no greater specificity for destruction of vascular structures conferred by using the short, 50-msec pulse duration. Operation of the argon laser with continuous irradiation leads to good clinical results, is less tiring and easier for the laser surgeon, allows larger areas to be treated more quickly, and often produces less mottling and more uniform PWS lightening than does pulsed irradiation.     

Low-fluence CO2 laser irradiation: selective epidermal damage to human skin

The interaction of normal human skin with low-fluence CO2 laser irradiation was studied using a three-phase approach. In phase one, freshly excised skin was observed immediately after impact. In phase two, skin irradiated 2 h prior to excision was studied. In phase three, human volunteers were irradiated and biopsied at time zero, 24 h and 48 h. Seventy-five sites were exposed and 60 biopsies were performed. The earliest histologic changes were observed in the 6-10 J/cm2 fluence (radiant exposure) range and these changes included spindle and vacuolar changes in the basal layer of the epidermis. Papillary dermal coagulation was present to a maximum of 0.03 mm. At fluences of 10-25 J/cm2, superficial dermal necrosis (0.06-0.08 mm) was observed. At fluences above 25 J/cm2, transepidermal necrosis was present with increasing papillary dermal necrosis that was in proportion to the energy density delivered. At 2h, basal vacuolar changes were accompanied by diffuse keratinocytic cell death where contact was maintained between the epidermis and dermis, while where separation occurred limited keratinocytic death was observed. The earliest changes occurred at lower threshold fluences (4-6 J/cm2). After 24 h, these doses resulted in extensive epidermal necrosis with focal acute inflammatory infiltrates. At 48 h, the degree of epidermal "slough" was proportional to the energy density delivered and was maximal with a fluence of 5.7 J/cm2 delivered whereas with a fluence of 3.8 J/cm2 thin slough (0.02 mm) was observed. These findings suggest that low-dose CO2 laser irradiation may provide a new approach to selectively damage the epidermis with minimal dermal damage.