Societal-Perceived Health Utility of Hypertrophic Facial Port-Wine Stain and Laser Treatment

Background: Port-wine stain (PWS) is a congenital capillary malformation occurring commonly in the head and neck. Left untreated, affected areas may darken and hypertrophy over time, resulting in pronounced disfigurement, risk of spontaneous hemorrhage, and functional impairment. The burden of hypertrophic facial PWS and the benefit of laser therapy have not heretofore been well characterized. Herein, the health utility of these two states is assessed among naïve observers. Methods: Naïve observers (n = 262) ranked the utility of four randomized health states (monocular blindness, binocular blindness, hypertrophic facial PWS, and laser-treated facial PWS) by means of visual analogue scale (VAS), standard gamble (SG), and time trade-off (TTO) techniques. Health states are presented using standardized facial photographs. Results: Health utilities (VAS, SG, and TTO) were reported as follows (mean ± standard deviation): monocular blindness (0.73 ± 0.21, 0.86 ± 0.21, 0.87 ± 0.18), binocular blindness (0.51 ± 0.26, 0.72 ± 0.27, 0.69 ± 0.27), hypertrophic facial PWS (0.71 ± 0.24, 0.83 ± 0.23, 0.83 ± 0.21), and laser-treated facial PWS (0.87 ± 0.16, 0.91 ± 0.18, 0.92 ± 0.16). Laser-treated facial PWS showed significantly higher utility measures than the untreated hypertrophic state (p < 0.001, all measures), with a difference of 3.24 quality-adjusted life years. Linear regression analysis revealed that non-Caucasian race and higher level of education were associated with lower SG and TTO utility scores for the hypertrophic facial PWS state among naïve observers. Conclusions: Societal-perceived utility of hypertrophic facial PWS is similar to that of monocular blindness. Laser-treated facial PWS is perceived significantly more favorably than the untreated hypertrophic state. These findings provide insight into the societal burden of facial PWS and impact of laser treatment, facilitating objective comparisons with other disparate disease states.

Laser applications for benign oral lesions

BACKGROUND AND OBJECTIVE

Different subspecialists treat benign intraoral lesions using various approaches including surgical excision, medical therapy, sclerotherapy, and laser photocoagulation. The goal of this study was to establish whether lasers could effectively target and destroy oral lesions containing endogenous chromophores, while minimizing injury to unaffected adjacent tissues and critical structures.

MATERIALS AND METHODS

This retrospective study involved 26 cases of benign oral lesions, both vascular and pigmented, which were addressed by means of selective laser treatment. Pathologies were port-wine stains, hereditary hemorragic teleangectasia, hemangiomas, venous and arteriovenous malformations, pyogenic granuloma, and hairy reconstructive flaps. Electronic medical records and photographic documentation were reviewed. Three blinded staff personnel not involved with patient care in this study evaluated photographs taken prior to the first and after the final laser treatments. Observers rated the percentage clearance of the lesions or the ablation of bleeding, and the assessed values were averaged for each patient.

RESULTS

An average of 30-95% lightening was observed in the intraoral port-wine stains, 90% in the hemangiomas, 70% in arteriovenous malformations, 81% for venous malformations, 86% for venous lakes, and 100% for the pyogenic granuloma. Bleeding was ablated in all hereditary hemorrhagic telangiectasia lesions treated using the pulsed dye laser with or without the Alexandrite laser. Intraoral hair growing on the skin paddle of microvascular flaps was completely removed in one of the three cases treated using the Alexandrite laser. In the two remaining cases, some hair removal was achieved, but because the residual hairs were grey or white (absence of melanocytic chromophore), photocoagulation was less effective.

CONCLUSION

Lasers are a safe and effective means to selectively destroy specific chromphores. Such specific targeting ensures complete destruction of pathological tissue, decreasing the possibility of relapse and/or recurrence. Selective laser treatment of benign intraoral lesions represents a niche application that fills a gap in the multidisciplinary management of several conditions such as oral vascular anomalies and hairy reconstructive flaps.

Quantitative three-dimensional assessment of port-wine stain clearance after laser treatments

BACKGROUND AND OBJECTIVE

Outcomes analysis of laser treatment for port-wine stains has been hampered by the lack of an objective measure of surface area and volume; moreover, treatment success is often gauged by clinician subjective assessment. Three-dimensional (3D) surface imaging has been applied in several medical disciplines to quantify surface changes, with promising results. We hypothesized that 3D surface imaging could be used to objectively measure changes in area and volume of port-wine stains following laser treatment.

STUDY DESIGN/MATERIALS AND METHODS

We performed a retrospective review of consecutive patients with port-wine stains treated over a 20-month time period. Area and volume of the lesions were measured using 3dMD photogrammetric software (3dMD, Atlanta, GA) before and after a series of sequential pulsed dye laser and/or alexandrite laser treatments.

RESULTS

Fifty-five patients with 59 port-wine stains were included in the study. The initial average measured area was 44.3 cm(2) ; final average measured area decreased to 36.9 cm(2) (P < 0.001). The average volume change was 1.20 cc for all PWS included in the study and 1.90 cc for lesions that received at least 5 laser treatments within the study period.

CONCLUSION

Three-dimensional photography demonstrated area and volume changes in patients with port-wine stains after laser treatments. Future studies to determine if statistically significant changes correlate with clinically appreciable changes are warranted.

RASA1 mutations and associated phenotypes in 68 families with capillary malformation-arteriovenous malformation

Capillary malformation-arteriovenous malformation (CM-AVM) is an autosomal-dominant disorder, caused by heterozygous RASA1 mutations, and manifesting multifocal CMs and high risk for fast-flow lesions. A limited number of patients have been reported, raising the question of the phenotypic borders. We identified new patients with a clinical diagnosis of CM-AVM, and patients with overlapping phenotypes. RASA1 was screened in 261 index patients with: CM-AVM (n = 100), common CM(s) (port-wine stain; n = 100), Sturge-Weber syndrome (n = 37), or isolated AVM(s) (n = 24). Fifty-eight distinct RASA1 mutations (43 novel) were identified in 68 index patients with CM-AVM and none in patients with other phenotypes. A novel clinical feature was identified: cutaneous zones of numerous small white pale halos with a central red spot. An additional question addressed in this study was the "second-hit" hypothesis as a pathophysiological mechanism for CM-AVM. One tissue from a patient with a germline RASA1 mutation was available. The analysis of the tissue showed loss of the wild-type RASA1 allele. In conclusion, mutations in RASA1 underscore the specific CM-AVM phenotype and the clinical diagnosis is based on identifying the characteristic CMs. The high incidence of fast-flow lesions warrants careful clinical and radiologic examination, and regular follow-up.

Removal of colored tattoos with the Q-switched alexandrite laser

The Q-switched alexandrite laser at 760 nm and 50- to 100-ns pulse duration has been shown to effectively remove blue-black as well as green, red, and mauve in seven human subjects with colored tattoos. An average of 9.0 treatments were required to completely remove the green pigment at an average fluence of 5.80 J/cm2 compared with an average of 9.7 treatments at an average fluence of 6.10 J/cm2 for red and an average of 10 treatments at an average fluence of 6.20 J/cm2 for mauve. Orange and yellow were unaffected by the alexandrite laser over a range of fluences tested.

Role of the Alexandrite laser for removal of tattoos

BACKGROUND AND OBJECTIVE

The development of the Alexandrite laser for the removal of blue-black tattoos is described.

STUDY DESIGN/MATERIALS AND METHODS

The responses of an animal study, using professionally tattooed skin and a human study involving 22 (professional and nonprofessional) blue-black tattoos, to the Alexandrite laser are reported.

RESULTS

Histopathologic evaluation of tattooed pig skin biopsies demonstrated the method of removal of dermal tattoo pigment. An average 11.6 treatments were required to remove completely the ten human blue-black professional tattoos compared to an average of 10.3 treatments to reach the same endpoint in six subjects with nonprofessional tattoos.

CONCLUSION

Of significance was the fact that unlike the Q-switched Ruby and Nd:YAG lasers where punctate bleeding and tissue splattering have been reported to occur during laser tattoo removal, epidermal integrity was maintained during exposure of tattooed skin to the Q-switched Alexandrite laser at therapeutic fluences used.

Wavelengths for laser treatment of port wine stains and telangiectasia

BACKGROUND AND OBJECTIVE

This report presents analytical modelling of the influence of wavelength on the amount of volumetric rate of heat produced in dermal blood vessels by millisecond laser radiation.

STUDY DESIGN/MATERIALS AND METHODS

A new anatomical model is proposed that represents port wine stains as well as telangiectatic lesions. It consists of a target blood vessel, representing the deepest dermal blood vessel that requires irreversible injury, and a layer of whole blood, representing all other dermal blood vessels above the target vessel. The laser light that interacts with the blood vessels is assumed to be diffuse. Selective photothermolysis is the basis for the analysis. We consider wavelengths between 577 nm and 600 nm, the argon laser wavelengths at 488/515 nm, and the frequency doubled Nd:YAG laser wavelength at 532 nm.

RESULTS

The rate of volumetric heat production of absorbed laser light in the target blood vessel is expressed analytically as a function of blood absorption, the concentration of additional dermal blood, and the depth of the target vessel.

CONCLUSION

The model explains why 585 nm is a good compromise for treating port wine stains that vary widely in number of dermal blood vessels. It predicts that wavelengths between 577 nm and 582 nm are excellent for the treatment of port wine stains in young children, and it suggests a possible explanation as to why the argon laser is sometimes said to be capable of treating dark mature port wine stains. The copper vapour laser wavelength at 578 nm, and the frequency doubled Nd:YAG laser wavelength at 532 nm, are predicted to be suitable for the treatment of port wine stains that contain, respectively, a small to moderate and a moderate number of dermal blood vessels. When laser beam spotsize becomes smaller, the best wavelength for producing maximal rate of heat in the target vessel is predicted to shift to 577 nm.

Pulsed dye laser treatment of recalcitrant verrucae: a preliminary report

Patients with recalcitrant warts on the fingers and hands, periungual, and other parts of the body including verrucae plana and plantar surfaces were treated using the pulsed dye laser at 585 nm, 450 usec, and a spotsize of 5 mm diameter. Of the 39 patients treated, 28 (72%) were cleared of their warts after an average of 1.68 treatments at fluences of 6.25-7.5 J/cm2. Seven (18%) patients had a reduction of between 80-95% of their warts after 1.3 treatments, and verrucae reduced by 50% in four of the 39 patients after one treatment. The average follow-up period of the 28 cases cleared of their warts has been 5 months. Of this group, those with periungual warts have been followed for up to 6.4 months, compared to 4.8 months for those with warts on other parts of their body, 4.0 months for those with finger and hand warts, and 2.0 months for plantar warts. Only one of the 28 patients has had a recurrence after 3 months of clearance.

Alteration of argon laser-induced scars by the pulsed dye laser

Ten patients with portwine stains (PWS) with test sites previously exposed to an argon laser were evaluated and subsequently treated with five pulsed dye (585 nm) laser treatments over a 10 month period. Clinical assessments, skin surface texture analyses using optical profilometry, and light microscopic histological evaluations were performed prior to commencement and at the end of the study in all ten patients. A change in the skin texture with return of skin markings approximating those of normal skin measured by optical profilometry was observed in the argon treated PWS skin following pulsed dye laser treatments.

Long-term neonatal rat aortic smooth muscle cell cultures: a model for the tunica media of a blood vessel

Cultured neonatal rat aortic smooth muscle cells have been used to study the synthesis and accumulation of extracellular matrix components in many laboratories. These cells are capable of accumulating large amounts of insoluble elastin in the extracellular matrix and can be maintained in culture for long periods of time without subcultivation. This study examined the elastin and collagen contents of such cells in culture for 5, 21 and 43 weeks. The percent elastin and collagen observed in the 43-week cultures were strikingly similar to that seen in the intact neonatal rat aorta. It should be noted that the percent collagen varied significantly between 5 weeks and 43 weeks, whereas that for elastin remained relatively constant throughout the same time course. Histological examination demonstrated that the elastin fibers in the extracellular matrix of the cultures were arranged in a pattern similar to the elastic lamellae of the aortic tunica media. Data presented here suggest that these cells in culture mimic the donor tissue from which they were derived with respect to elastin and collagen content as well as elastic fiber arrangement, and possibly represent an organotypic culture of the medial layer of a blood vessel.

Pulsed dye laser treatment of benign cutaneous pigmented lesions

Superficial benign cutaneous pigmented lesions that commonly present to the dermatologists and plastic surgeons have been treated by many conventional modalities such as dermabrasion, depigmenting creams as well as several types of lasers. Many of these treatment modalities lack specificity of injury, which has meant that normally pigmented and even non-pigment containing structures such as collagen as well as the hyperpigmented lesion itself have all been indiscriminately destroyed. This has resulted variously in hypopigmentation, hyperpigmentation, in addition to scar formation in some cases. A coaxial 504 nm laser with a pulse duration of 300 nsec was used to treat fifty two patients with superficial benign cutaneous pigmented lesions. Although the number of treatments required to clear the lesion varied according to the type of lesions being treated, on average, between 2 and 4 treatments were required to completely eradicate the superficial benign cutaneous pigmented lesions using 504 nm pulsed dye laser. The skin at the site successfully cleared of the pigmented lesion remained normal in skin color, texture, markings, and mobility.

Pulse duration effects on cutaneous pigment

Melanin, an endogenous chromophore in pigment containing cells in skin, is being specifically altered by lasers using the principle of selective photothermolysis (SPT). This implies that a combination of specific laser parameters of wavelength, pulse duration, spotsize, and energy density are required to confine the delivered laser energy to the targeted cells alone. Because the bulk of cutaneous pigment is localized to epidermal basal cells, pigmentary incontinence has been found to occur in skin exposed to laser irradiation. This study demonstrates that pulse duration or exposure time of the laser affect the severity of pigmentary incontinence induced. Pigment granules are more abundant, aggregated, and located deeper in the dermis following exposure to 500 nsec pulse duration than 100 nsec at a wavelength of 504 nm. This relationship appears to be independent of the laser energy density used.

EMLA for laser treatment of portwine stains in children

Vascular-specific lasers with pulse durations of between 300 and 500 microseconds are the treatment of choice for portwine stains (PWS), particularly in children. Although the discomfort felt following laser irradiation from a single pulse is transient, these sensations are intensified when multiple pulses are delivered over a confined area of skin. Because 75-80% of PWS are located in the head and neck regions, laser treatment of these sites tends to be more painful than those located in most other parts of the body. A prospective double blind randomized study, assessing pain during laser irradiation on PWS skin occluded with either EMLA, placebo, or no cream (control) was performed in 73 PWS subjects between 5 and 16 years of age. Analysis of the data showed that the pain scores for EMLA-treated sites were the smallest, the control scores tended to be the highest, with the placebo scores in the middle. The differences between the treatments were significant (P < 0.0001).

Treatment of ulcerated hemangiomas with the pulsed tunable dye laser

Hemangiomas are the most common tumor of infancy and are characterized by rapid growth during the first 6 months of life. During the rapid growth phase, approximately 5% to 10% of the hemangiomas ulcerate. Ulcerated lesions are painful, may bleed, and are at risk for bacterial infection. Previous therapy has included daily local wound care, topical antibiotics, and local and systemic steroids. We treated nine infants (eight female and one male) with ulcerated hemangiomas by means of a vascular-specific (585-nm) pulsed (450-microsecond) tunable dye laser. Eight of the nine patients had a single ulceration, whereas one patient had two ulcerations within a large hemangioma. Six of the ulcerations healed with a single laser treatment. One ulceration required two treatments to heal, and the remaining two required three treatments. Pain was subjectively decreased within 2 to 3 days in all patients after a single treatment. The pulsed tunable dye laser should be considered in the treatment of all ulcerated hemangiomas.

Laser treatment of benign cutaneous vascular lesions

Benign cutaneous vascular lesions have been treated with a wide array of modalities. Lasers are a comparatively new form of treatment for cutaneous blood vessel abnormalities. Initially, results following laser treatment were disappointing, primarily because of widespread thermal injury to surrounding normal tissue. Recent developments in laser technology and the introduction of the tunable dye laser offer the ability to selectively target laser energy at specific chromophores such as oxyhemoglobin. The technique of selective photothermolysis provides successful treatment of benign vascular lesions with minimal damage to adjacent structures.

Location of port-wine stains and the likelihood of ophthalmic and/or central nervous system complications

Of 310 patients with port-wine stains, 68% had more than one dermatome involved; 85% had unilateral and 15% had a bilateral distribution of their port-wine stain. At the time of examination, 8% of all patients with trigeminal port-wine stains had evidence of eye and/or central nervous system (CNS) involvement. Extensive involvement, with port-wine stain over the trunk and extremities as well as the head and neck, was observed in 12%. Patients who did not have port-wine stains on the areas served by branches V1 and V2 of the trigeminal nerve had no signs or symptoms of eye and/or CNS involvement. Port-wine stains of the eyelids, bilateral distribution of the birthmark, and unilateral port-wine stains involving all three branches of the trigeminal nerve were associated with a significantly higher likelihood of having eye and/or CNS complications. Twenty-four percent of those with bilateral trigeminal nerve port-wine stains had eye and/or CNS involvement compared with 6% of those with unilateral lesions. All those who had eye and/or CNS complications had port-wine stain involvement of the eyelids; in 91% both upper and lower eyelids were involved, whereas in 9% only the lower eyelid was involved. None of those with upper eyelid port-wine stains alone had eye and/or CNS complications. In addition, 3 (75%) of the 4 subjects with seizures alone had bilateral port-wine stain involvement. A third group, these with unilateral V1, V2, and V3 port-wine stains, had eye and/or CNS complications in 3 (19%) of 16 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

585 nm for the treatment of port-wine stains

Although the flashlamp-pulsed-dye laser has been successfully used for the treatment of port-wine stains (PWS) at 577 nm, a number of adult patients had incomplete clearance of their birthmarks with this treatment modality because of residual vessels lying beyond the 0.75-mm penetration depth of 577-nm irradiation. Fifteen adult patients, of whom nine were previously treated with limited success at 577 nm (group A), and six untreated patients (group B) were included in the study. For the group A patients, treatment with 585 nm produced successful clearance of the birthmark. For the six patients in group B, parallel treatment of different sites of the same lesion coupled with skin biopsies and histologic examination revealed that a change in the wavelength from 577 to 585 nm allowed the laser light to penetrate from the midreticular dermis into the subcutaneous fat. This explained the clearance achieved at 585 nm and not at 577 nm.

Histologic comparison of the pulsed dye laser and copper vapor laser effects on pig skin

Albino pig skin was exposed to the copper vapor (CVL) and flash-lamp pulsed dye (PDL) lasers at 578 nm with a 3 mm diameter spotsize over a range of fluences until purpura and whitening were first established. The total irradiation time was the parameter that was varied in order for the CVL to reach the desired fluence. The lowest fluence producing each clinical endpoint was designated the threshold fluence: 34 J/cm2 was required to produce purpura using the CVL compared to 7.5 J/cm2 with the PDL laser. Histologically, skin exposed to purpura fluences from the CVL revealed the presence of constricted, disrupted papillary dermal blood vessels with trapped RBC's within them which were unlike those exposed to PDL where the irradiated vessels were dilated and packed with masses of intravascular agglutinated RBC's. The whitening threshold fluences for the CVL and PDL lasers were 67 J/cm2 and 29 J/cm2, respectively. Streaming of epidermal cells and dermal collagen denaturation were observed in CVL irradiated skin, compared to occasional dyskeratotic epidermal cells and focal dermal collagen denaturation following PDL exposure. The mechanisms responsible for the clinical and histologic changes produced by the two laser systems are discussed.

Action spectrum of vascular specific injury using pulsed irradiation

It has been clearly demonstrated that cutaneous blood vessels will be selectively damaged by a laser whose wavelength matches one of the three absorption spectral peaks of the chromophore, oxyhemoglobin, for example, 577 nm. A restriction in the application of this wavelength for the treatment of benign cutaneous vascular tumors, such as portwine stains, has been the penetration depth of 577 nm irradiation of approximately 0.5 mm from the dermal epidermal junction (DEJ). This study was undertaken to establish whether it was possible to increase the penetration depth from 0.5 mm by changing the wavelength to beyond 577 nm in albino pig skin. Results from this study confirm that penetration depth increases from 0.5 to 1.2 mm by changing the wavelength from 577 to 585 nm at 4 J/cm2, while maintaining the same degree of vascular selectivity as that previously described after 577 nm irradiation. This occurred in spite of a mismatch in the wavelength between 585 nm and the oxyhemoglobin absorption peak of 577 nm. Unlike 585 nm irradiation and in contrast with theoretical predictions, 590 nm laser light did not penetrate as deeply as 585 nm. Not only was there a reduction in the penetration depth of the laser beam from 1.2 mm at 585 nm to 0.8 mm at 590 nm, at 4 J/cm2, but there was also a decrease in vascular selectivity in albino pig skin exposed to 590 nm irradiation.

Effect of wavelength on cutaneous pigment using pulsed irradiation

Several reports have been published over the last two decades describing the successful removal of benign cutaneous pigmented lesions such as lentigines, café au lait macules' nevi, nevus of Ota, and lentigo maligna by a variety of lasers such as the excimer (351 nm), argon (488,514 nm), ruby (694 nm), Nd:YAG (1060 nm), and CO2 (10,600 nm). Laser treatment has been applied to lesions with a range of pigment depths from superficial lentigines in the epidermis to the nevus of Ota in the reticular dermis. Widely divergent laser parameters of wavelength, pulse duration, energy density, and spotsizes have been used, but the laser parameters used to treat this range of lesions have been arbitrary, with little effort focused on defining optimal laser parameters for removal of each type. In this study, miniature black pig skin was exposed to five wavelengths (504, 590, 694, 720, and 750 nm) covering the absorption spectrum of melanin. At each wavelength, a range of energy densities was examined. Skin biopsies taken from laser-exposed sites were examined histologically in an attempt to establish whether optimal laser parameters exist for destroying pigment cells in skin. Of the five wavelengths examined, 504 nm produced the most pigment specific injury; this specificity being maintained even at the highest energy density of 7.0 J/cm2. Thus, for the destruction of melanin-containing cells in the epidermal compartment, 504 nm wavelength appears optimal.

Treatment of children with port-wine stains using the flashlamp-pulsed tunable dye laser

Thirty-five children, three months to 14 years of age, with disfiguring port-wine stains were treated with a flashlamp-pulsed tunable dye laser. All had complete clearing of the stains after an average of 6.5 laser treatments to each lesional area; skin over bony prominences required approximately half as many sessions as skin on the cheek. Children less than seven years old required fewer sessions (mean +/- SD, 5.8 +/- 1.1) than older children (7.1 +/- 1.1; P less than 0.05). Treated skin was identical in texture and color to adjacent normal skin in 33 (94.3 percent) of the children, whereas 2 (5.7 percent) had small, isolated, depressed scars in areas accidentally traumatized soon after laser treatment. The only other side effect was transient hyperpigmentation, which occurred in 20 patients (57 percent). These results can be attributed to two distinguishing characteristics of the flashlamp-pulsed tunable dye laser: an emission wavelength of 577 nm, theoretically ideal for selective absorption by the intravascular target oxyhemoglobin, and a pulse duration of 360 microseconds, which closely matches the thermal relaxation time for dermal blood vessels and hence avoids diffuse nonspecific thermal necrosis with subsequent scarring of the treated skin.

Ultrastructural changes in red blood cells following pulsed irradiation in vitro

The careful choice of a combination of laser parameters such as wavelength, pulse duration, and dose has provided a means for confining laser energy to specific targets within tissue such as oxyhemoglobin within the cutaneous microvasculature. In the process of achieving such vascular selectivity, certain ultrastructural changes in red blood cell (RBC) cytoplasm have been observed, such as the generation of intracytoplasmic electron-lucent spherical structures. These structures, ranging in size from 80 to 1000A, were seen in RBCs exposed to laser doses at and above threshold, and appeared to represent a morphologically novel form of highly-specific tissue injury. This in vitro study using RBC in phosphate buffered saline (PBS) was undertaken to better understand the mechanism(s) that could have been responsible for these unique morphologic changes. We conclude that the intracytoplasmic electron-lucent spherical structures seen within RBCs were heat-fixed molds formed around vaporized water bubbles and were not produced by the release of oxygen from the oxyhemoglobin moiety during 577-nm laser irradiation.

193 nm excimer laser selective ablation of in vivo guinea pig epidermis

We have previously shown that 193 nm excimer laser irradiation cleanly and effectively ablates avascular tissue with minimal thermal damage to surrounding adjacent structures. In this study, the 193 nm excimer laser is used to remove guinea pig epidermis in vivo. The epidermis can be totally ablated with thermal damage extending only superficially into the dermis. Reepitheliazation of the ablated area takes place in 1 week or less. This technique may be applicable to the removal of benign epidermal lesions.

Selective vascular coagulation of rabbit colon using a flashlamp-excited dye laser operating at 577 nanometers

Previous studies have demonstrated that brief pulses of selectively absorbed optical radiation can be used to confine thermal injury to pigmented targets within tissues. We performed studies in rabbits to assess the usefulness of this technique for selectively coagulating the colonic vasculature. By measuring the optical absorbance of rabbit colon with a spectrophotometer, it was determined that hemoglobin exhibits strong absorption relative to the rabbit colon at a wavelength of 577 nm. Because light must be absorbed to affect tissue, it was hypothesized that laser pulses of this wavelength would selectively damage blood vessels. This hypothesis was tested by examining the effect of 300-microseconds-long 577-nm laser pulses on rabbit colon in vivo. For delivered radiant exposures between 4 and 8 J/cm2, selective coagulation of the colonic vasculature could be produced without damage to the surrounding colon. At greater radiant exposures, vessel hemorrhage was occasionally noted but no transmural thermal injury was produced with delivered radiant exposures as high as 22 J/cm2. This technique may form the basis of a safe and simple treatment of vascular lesions of the colon such as angiodysplasia.

Laser therapy for selected cutaneous vascular lesions in the pediatric population: a review

Three cutaneous vascular lesions of childhood (the spider angioma [nevus araneus], the strawberry hemangioma, and the port wine stain) are reviewed, with particular emphasis on the present and future role of laser therapy in their management.

Congo red binding of elastin in aortic smooth muscle cell cultures

These studies demonstrate that the strong binding capacity of elastin for Congo red can be used to advantage in aortic smooth muscle cell cultures. A fibrous elastin network fluoresces when Congo red is added. Congo red does not alter accumulation of elastin or of total protein, even when the cells are grown in the presence of the dye for long periods of time, indicating that it is not toxic. Porcine pancreatic elastase was used to solubilize elastin in these cultures, to determine the molar ratio of Congo red to elastin, thus making it possible to estimate the amount of elastin solubilized when the cultures are injured. Congo red binding to elastin will be useful in studying elastin accumulation and/or degradation in vitro and in vivo.

The treatment of port-wine stains by the pulsed dye laser. Analysis of pulse duration and long-term therapy

A flashlamp-pumped pulsed dye laser at 577 nm was evaluated in the treatment of port-wine stains. The degree of lesional lightening was compared following laser exposure with pulse durations of 20 and 360 microseconds. In addition, lesional therapy using the 360-microseconds pulse duration was evaluated for lightening and side effects following long-term patient observation and after repeated treatments of the same site. A total of 52 patients with port-wine stain were treated; their average age was 29 years, with eight patients less than 18 years, of whom 29 had comparative test site placement for the different pulse durations. Of these 29 patients, 25 demonstrated greater lightening at the 360-microseconds pulse duration test site. All 52 patients proceeded to receive full treatment placement with the 360-microseconds pulse duration, which resulted in an overall lightening of 42% after the initial treatment and 68% after re-treatment sessions. Forty-four percent of the patients had equal to or greater than 75% lesional lightening. Pretreatment anesthesia was unnecessary and only minimum posttreatment care was required. Mild adverse effects of epidermal change, depression, or pigmentary change appeared in only four cases and was limited to less than a 2% area in each of these lesions. These side effects did not recur when the lesions were re-treated at lower energy dosages. No posttreatment sclerosis or scarring appeared, even after multiple retreatment sessions to the same area, regardless of the anatomic location, color of the lesion, or age of the patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Spotsize effects on guinea pig skin following pulsed irradiation

Laser irradiation parameters such as wavelength, irradiance (W/cm2), and pulse duration have been clearly shown to influence the extent to which tissue is damaged. The careful choice of these parameters can result in confining laser injury to specific targets in tissue. Spotsize, a parameter not commonly appreciated in the application of lasers to medicine and surgery, has been shown, in this study, to contribute to the ultimate outcome of laser effects in tissue. A series of histological events occurring in the skin are demonstrated to be directly related to the effects of spotsize on tissue at a fixed exposure time and wavelength. Many of these changes could contribute to unwanted adverse effects, such as scarring, which occur following certain laser therapies.

Factitious dermatosis masquerading as recurrent herpes zoster

A 35-year-old nurse's aide presented with monthly episodes, during her menses, of self-induced cutaneous lesions intended to simulate recurrent herpes zoster. Features of the clinical presentation that prompted the correct diagnosis are discussed.

Pulsed dye laser (577 nm) treatment of portwine stains: ultrastructural evidence of neovascularization and mast cell degranulation in healed lesions

Portwine stains were examined before, immediately after, and 1 yr after successful clearance by a pulsed dye laser (577 nm) using ultrastructural techniques. Dilated vascular channels and mast cell hypoplasia characterized lesional skin before treatment. Immediately after treatment, widespread selective vessel necrosis, similar to changes previously described, was observed. One year after laser irradiation, the abnormally ectatic portwine stain vessels had been replaced by small venules and arterioles, similar in number and diameter to blood vessels in normal skin; the only difference noted was that these new vessels were surrounded by easily identifiable mast cells. Many of these mast cells exhibited evidence of activation and degranulation. We conclude that mast cells may play an important role in the neovascularization of portwine stains treated by 577-nm dye laser irradiation.

Treatment of port-wine stains at 577 nm: clinical results

A pulsed, dye laser at 577 nm was used to treat 65 patients with port-wine stains. Results clearly indicate that the laser parameters of dose, wavelength, and pulse duration contribute to the outcome of laser treatment of port-wine stains.

Ultraviolet excimer laser ablation: the effect of wavelength and repetition rate on in vivo guinea pig skin

Multiple dermatologic conditions that are currently treated with traditional cold-knife surgery are amenable to laser therapy. The ideal surgical treatment would be precise and total removal of abnormal tissue with maximal sparing of remaining structures. The ultraviolet (UV) excimer laser is capable of such precise tissue removal due to the penetration depth of 193 nm and 248 nm irradiation of 1 micron per pulse. This type of ablative tissue removal requires a high repetition rate for efficient lesional destruction. Excimer laser radiation at 193 nm is capable of high repetition rates, which are necessary while 248 nm radiation causes increasing nonspecific thermal injury as the laser repetition rate is increased.

Ultrastructure: effects of melanin pigment on target specificity using a pulsed dye laser (577 nm)

It has been shown recently that brief pulses of 577 nm radiation from the tunable dye laser are absorbed selectively by oxyhemoglobin. This absorption is associated with highly specific damage to superficial vascular plexus blood vessels in those with lightly pigmented (type I-II) skin. To determine whether pigmentary differences in the overlying epidermis influence this target specificity, we exposed both type I (fair) and type V (dark) normal human skin to varying radiant exposure doses over 1.5-microsecond pulse durations from the tunable dye laser at a wavelength of 577 nm. Using ultrastructural techniques, we found in type I skin that even clinical subthreshold laser exposures caused reproducible alterations of erythrocytes and adjacent dermal vascular endothelium without comparable damage to the overlying epidermis. In contrast, degenerated epidermal basal cells represented the predominant form of cellular damage after laser exposure of type V skin at comparable doses. We conclude that epidermal melanin and vascular hemoglobin are competing sites for 577 nm laser absorption and damage, and that the target specificity of the 577 nm tunable dye laser is therefore influenced by variations in epidermal pigmentation. This finding is relevant to the clinical application of the tunable dye laser in the ablative treatment of vascular lesions. We also found on ultrastructure that the presence of electron-lucent circular structures of approximately 800 A in diameter were observed only at and above clinical threshold doses in those with type I skin and at the highest dose of 2.75 J/cm2 in type V skin. It has been proposed that these structures might be heat-fixed molds of water vapor. Both this and ultrastructural changes of epidermal basal cells demonstrate mechanisms responsible for alteration of tissue after exposure to 577 nm, which are discussed.

The pulsed dye laser: its use at 577 nm wavelength

The ability to increase laser-induced cutaneous blood vessel damage selectivity is dependent upon optimizing various intrinsic laser parameters. Varying the laser emission wavelength, pulse duration, and/or incident energy dosage allows the clinician potential improvement in the laser treatment of cutaneous small blood vessel processes such as port-wine hemangioma and telangiectasia. The pulsed dye laser at 577 nm and a pulse duration of 300 to 400 microseconds, incorporates desired laser parameters into its design. Clinical evaluation of the therapeutic outcome with this laser reveals favorable results while significantly minimizing potential adverse side effects.

Tunable pulsed dye laser for the treatment of benign cutaneous vascular ectasia

A tunable pulsed dye laser emitting at 577 nm and 360 microseconds pulse width was used to treat benign cutaneous vascular ectasias other than port wine stain in 77 patients. Except for leg telangiectasias (34 patients), the overall response was excellent. Forty-two of forty-five patients with hemangiomas, spider nevi, angioma serpiginosum, venous lakes or facial telangiectasias showed excellent results after 1-4 consecutive treatments. Scarring was observed in none of the patients. These results confirm previous data on the use of the tunable dye laser in the treatment of port wine stain, and suggest that 577 nm wavelength and 360 microseconds pulse width allow the selective photothermolysis of vascular cutaneous ectasias with better clinical results than previously reported.

Effect of dye laser pulse duration on selective cutaneous vascular injury

The pulsed dye laser at 577 nm, a wavelength well absorbed by oxyhemoglobin, causes highly selective thermal injury to cutaneous blood vessels. Confinement of thermal damage to microvessels is, in theory, related to the laser exposure time (pulsewidth) on selective vascular injury. This study investigates the effect of 577 nm dye laser pulsewidth on selective vascular injury. Nine Caucasian, normal volunteers received 577 nm dye laser exposures at pulsewidths of 1.5-350 microseconds to their skin. Clinical purpura threshold exposure doses were determined in each volunteer, and biopsies of threshold and suprathreshold doses were examined in each volunteer. The laser exposure dose required to produce purpura increased as pulsewidth increased in all 9 subjects (p less than 0.001). This finding corresponds to laser pulsewidths equal to or exceeding the thermal relaxation times for dermal blood vessels. Histologically, vessel damage was selectively, but qualitatively, different for short vs long pulsewidths. Pulsewidths shorter than 20 microseconds caused vessel wall fragmentation and hemorrhage, whereas longer pulsewidths caused no significant hemorrhage. The purpura noted clinically appears to be due to a coagulum of intralumenal denatured erythrocytes. At 24 h, there was marked vessel wall necrosis at all pulsewidths. The short pulsewidths may cause erythrocyte vaporization, rapid thermal expansion, and mechanical vessel rupture with hemorrhage. Long pulsewidths appear to cause thermal denaturation with less mechanical vessel damage. The selective, nonhemorrhagic, vascular necrosis caused by the long-pulsewidth dye laser may lead to a more desirable clinical outcome in the therapy of blood vessel disease processes.

Histologic responses of port-wine stains treated by argon, carbon dioxide, and tunable dye lasers. A preliminary report

Although the blue-green argon laser light has been used successfully to treat port-wine stains (PWSs) for many years, it produces substantial epidermal damage. We have previously shown in normal human skin that pulsed yellow tunable dye lasers (577-nm wavelength) can cause highly selective damage to cutaneous microvessels with minimal injury to the overlying epidermis. Pulsed tunable dye lasers also produce selective vascular injury in the abnormal vessels of PWSs, with clinically apparent lightening of the lesions. Both epidermal injury and fibrosis are less severe with this laser treatment than with argon and carbon dioxide laser treatments. Clinical and histologic responses of PWSs treated by argon, CO2, and pulsed yellow dye lasers were compared and followed up for one month in three patients. Although larger and longer-term clinical trials are necessary to fully evaluate this new treatment modality, it appears that pulsed yellow laser radiation offers a more selective, less traumatic, and probably superior form of treatment for PWSs.

Effect of cutaneous hypoxia upon erythema and pigment responses to UVA, UVB, and PUVA (8-MOP + UVA) in human skin

The effect of oxygen deprivation upon UVA-, UVB-, and PUVA-induced pigment and erythema responses in normal human skin was examined. Before exposure, varying degrees of hypoxia in the skin of the forearm were achieved by inflating a sphygmomanometer cuff applied to the upper arm. After the transcutaneously measured pO2 had stabilized, sites on the inner forearm were exposed to UVA, UVB, or 8-MOP + UVA radiation, to determine dose thresholds for the induction of erythema and pigmentation at different cuff pressures. Inflation of the cuff to greater than systolic pressure completely inhibited immediate and delayed pigment responses (IPD, DT) to UVA doses greater than 10 times the normal pigmentation threshold dose. UVA-induced delayed erythema responses were partially inhibited by cuff inflation: 2.7 times the minimal erythema dose of UVA was necessary to cause an erythema response when exposure occurred during vascular occlusion. In contrast, erythema and pigment responses to UVB and PUVA were unaltered by cuff pressures exceeding systolic pressure during exposure. Inhibition of UVA-induced erythema and pigment responses by vascular occlusion were reversed by the transcutaneous diffusion of 100% O2. These findings indicate that the cutaneous responses to UVA and UVB occur by separate pathways differing with respect to O2 dependence. Our findings agree with those of other studies which indicate that PUVA-induced phototoxicity and melanogenesis are not O2-dependent.

Tunable dye laser (577 nm) treatment of port wine stains

Despite steady improvement in the laser treatment of port wine stains (PWS), hypertrophic scarring remains a serious side-effect in approximately 10% of patients. The tunable dye laser (577 nm) has been shown to cause selective vascular destruction in normal and PWS skin. We have treated ten patients using a tunable dye laser (577 nm, 300 mu sec) resulting in clearing of the PWS without any evidence of hypertrophic scarring. Treatment requires no anesthesia or wound care, and there were no postoperative infections.

Effect of skin temperature on selective vascular injury caused by pulsed laser irradiation

The effect of skin temperature on vascular-specific injury caused by pulsed laser irradiation was examined. Ten healthy human volunteers were exposed to 1.5 microsecond pulses from a dye laser tuned to 577 nm. Compared to normothermic conditions (33 degrees C skin temperature) significantly more laser energy (p less than 0.01) was required to produce grossly visible purpura when the skin was cooled to 20 degrees C or heated to 40 degrees C. Histologically, laser-induced damage was confined to blood vessels at all three skin temperatures studied. At purpura threshold dose, there was intravascular agglutination without extravasation of red blood cells at 20 degrees C whereas at 33 degrees and 40 degrees C there was extravasation of red blood cells.

Ultrastructural changes in human skin after exposure to a pulsed laser

Selective vascular injury following irradiation using a pulsed laser source at 577 nm was examined using ultrastructural methods in the skin of 3 fair-skinned healthy human volunteers. This vascular-specific damage was confined to the papillary dermis. Red blood cells were altered in several ways. As well as an increase in the electron density, configurational distortion modified the normal biconcave forms to ameboid structures. The most interesting finding was the appearance within these altered cells of well-defined circular/oval electron-lucent areas of 800 A diameter, possibly representing a heat-fixed record of steam formation within the red blood cell. In addition, considerable degenerative changes were evident in endothelial cells and pericytes, while mast cells, neutrophils, histiocytes, and fibroblasts as well as collagen bundles immediately surrounding most laser-damaged blood vessels appeared normal.