Advanced Techniques in Dermatologic Surgery - part 6

190 Kauvar Diode Lasers (Table 6) Millisecond-domain diode lasers are available at wavelengths of 800, 810, and 930nm. Like the alexandrite lasers, these systems are effective in treating larger telangiectasia, venulectasia, and feeding reticular veins of the lower extremities (42,43). Long-Pulsed Nd:YAG Lasers (Table 7) Compared to the other near-infrared lasers being applied to the treatment of cutaneous vascular lesions, Nd:YAG lasers provide enhanced depth of penetration (up to 5.0mm in depth) and minimal interference from melanin absorption. Long-pulsed Nd:YAG lasers are effective for the treatment of telangiectasia, venulectasia, and reticular veins of the legs because of their ability to photocoagulate larger diameter, more deeply situated vessels (44,45). Telangiectasia and venulectasia of the face can be successfully treated by using small (1.0–3.0mm) spot sizes, and by using high fluences to compensate for the decreased absorption coeffi-cient for hemoglobin at this wavelength (46). The pulsed Nd:YAG lasers are equipped with a variety of cooling systems including water-cooled chambers applied directly to the skin (Laserscope LyraÕ, Altus Cool-glideÕ, ESC VasculightÕ) and cryogen spray cooling (Laser Aesthetics VariaÕ and Candela Gentle YAGÕ). Intense Pulse Light Source (Table 8) The intense pulsed light (IPL) source was developed by ESC Medical (now Lumenis) in an effort to maximize the efficacy in treating leg veins. This high intensity pulsed flashlamp light source delivers broadband Table 6 Diode Lasers Light SLP Laser MedioStarÕ ApogeeÕ SkinPulseÕ ApexÕ SheerÕ EpiStarÕ 1000Õ Manufac-turer Asclepion-Meditec (Jena, Cynosure Dornier Iridex (Chelms- (Munich, (Mountain-ford, MA, Germany) view, CA, Lumenis (Santa Clara, Nidek Palomar (Fremont, (Burling-CA, ton, MA, Germany) Wavelength 810 (nm) Pulse 5–30 duration (msec) U.S.A.) 800 50–500 940 10 to continu-ous U.S.A.) 800 5–100 CA, U.S.A.) 800 5–100 U.S.A.) 810 200 U.S.A.) 810 50–100 Maximum fluence (J/cm2) Cooling 64 50 Contact Air 600 5–60 Contact 10–60 Contact 179 Contact Laser Treatment of Vascular Lesions 191 Table 7 Long-Pulsed Nd:YAG Lasers CoolGlideÕ/ Laser VantageÕ Gentle YAGÕ VariaÕ LyraÕ ImageÕ MydonÕ Manufac- Cutera Candela, ICN Laserscope Sciton Wavelight turer (Burlingame, CA, U.S.A.) (Wayland, MA, U.S.A.) (Costa Mesa, CA, U.S.A.) (San Jose, CA, U.S.A.) (Palo Alto, CA, U.S.A.) (Erlangen, Germany) Wavelength 1064 1064 1064 1064 1064 1064 (nm) Pulse duration (msec) Maximum fluence (J/cm2) Cooling 0.1–300 300 Contact 3 10–70 Cryogen 0.3–200 500 Cryogen/ contact 10–100 200 Contact 5–200 10–400 Contact/air 20–140 15–400 Contact/air light from 515 to 1100nm (47). Single, double, or triple pulses in the 2- to 20-millisecond domain can be delivered in a synchronized fashion. The broad emission spectrum, in the visible and near infrared region, targets both oxygenated and deoxygenated hemoglobin. The longer wavelengths penetrate deeper into the skin, enabling photocoagulation of deeper vessels, and the longer pulse durations produce uniform heating of larger vessels without inducing vessel rupture. Several IPL sources are now available. This technology has also been applied to the treatment of port wine stains, superficial hemangiomas (48), and facial telangiectasia Table 8 IPL Sources Light source Manufacturer Wavelength (nm) Pulse duration (msec) Maximum fluence (J/cm2) Cooling ProliteÕ Alderm (Irvine, CA, U.S.A.) 500–900 10–50 QuantumÕ Lumenis (Santa Clara, CA, U.S.A.) 515–1200 2–7 45 Contact VasculightÕ Lumenis (Santa Clara, CA, U.S.A.) 515–1200 0.5–2.5 90 Contact EsteluxÕ Palomar (Burlington, MA, U.S.A.) 500–1200 10–100 4–12 Contact Abbreviation: IPL, intense pulsed light. 192 Kauvar (49) yielding good results. IPL technology presently finds its application mainly in nonablative photorejuvenation to improve the pigmentary, vas-cular, and textural irregularities of photodamaged skin. CLINICAL APPLICATIONS Port Wine Stains The pulsed dye laser remains the treatment of choice for most port wine stains. Treatment of macular and mildly hypertrophic port wine stains with the 585-nm, 0.45-millisecond pulsed dye laser produces remarkable clinical lightening with minimal side effects. Multiple treatments are required for significant lightening. Early studies demonstrated 75% or more lightening in approximately 36% to 44% of adult patients with port wine stains, and at least 50% lesional lightening in 75% of patients after a total of four treatments (12,14–19,50). The laser has been proven safe and effective, even after 10 to 25 repetitive treatments (7). Treatment may be initiated soon after birth, without adverse effect. Clearing of port wine stain lesions depends on their anatomic location and size. Port wine stains located on the forehead, lateral cheeks, and neck respond better than those located on the central facial regions, specifically areas supplied by the second branch of the trigeminal nerve (51). Smaller lesions with areas less than 20cm2 respond far more quickly than larger lesions with areas greater than 20cm2. Head and neck port wine stains respond most favorably. Truncal lesions respond better than port wine stains located on the extremities, with distal extremity lesions being the most resistant. Newer generation pulsed dye lasers with a wavelength of 595nm and pulse duration of 1.5 milliseconds enable faster clearance of port wine stains in infants and adults. In studies using this laser in conjunction with cryogenspraycoolingtotreat16infants under12monthsofagewithfacial port wine stains, there was greater than 75% lightening in 63% of patients after four treatments using energy fluences of 11 to 12J/cm2 (35). Prospec-tive side-by-side comparison studies of hypertrophic adult port wine stains treated with energy fluences of 12 to 14J/cm2 using the 595-nm, 1.5-milli-second laser demonstrated increased clearance compared to a fluence of 10J/cm2, both in conjunction with cryogen spray cooling (36). Treatment of port wine stains with the 585-nm, 0.45-millisecond laser is usually performed with the largest spot size available to prevent reticulation. Typical treatment fluences using the 7mm spot are 5.0 to 7.0J/cm2 and 5.0 to 6.0J/cm2 with a 10-mm spot size, depending on the age of the patient and the thickness of the lesion. Using the 595-nm, 1.5-millisecond pulseddye lasersinconjunction withcryogen spray cooling, fluences of 8.0 to 11.0J/cm2 are used with a 7-mm spot size, and fluences of 5.0 to 6.5J/cm2 are used with the 10-mm spot size in infants and children. For adults with hypertrophic lesions, fluences up to 13J/cm2 can be used with a 7-mm spot size and fluences up to 7.5J/cm2 with a 10-mm spot size. Laser Treatment of Vascular Lesions 193 Determination of the appropriate fluence should be assessed with test performed on the target sites during the initial evaluation. Immediately after treatment with the 585-nm, 0.45-millisecond pulsed dye laser, intense blue–black purpura develops for approximately 10 to 14 days. The intensity and duration of purpura is significantly lower while using pulse duration of 1.5 milliseconds. If crusting occurs, patients are instructed to apply a topical antibiotic such as bacitracin or poly-sporin ointment daily until it resolves. Following the resolution of pur-pura, lesional lightening takes place over a period of four to six weeks. Repeat treatments are performed every 6 to 10 weeks until maximal lesional clearing is achieved. Even after 20 treatment sessions, further lesional lightening may be achieved (7). The development of various skin-cooling methods has obviated the necessity for local or general anesthesia in most cases. With the exception of young children, most infants, teenagers, and adults tolerate the treatment well with the use of a topical anesthetic cream such as Emla or Elamax. While pulsed dye laser technology remains the standard of care for port wine stain treatment, other technology has been successfully used for this indication. The IPL has been used to lighten port wine stains. Twenty-eight of forty patients treated in one study achieved greater than 75% lesional clearance after an average of four treatments for pink lesions, 1.5 for red ones, and 4.3 for purple-colored port wine stains (52). The lightening of the red or purple port wine stains by the three-millisecond long pulse alexandrite laser has also been found by the author and others (Dierickx C, personal communication) (52). Hemangiomas Superficial (capillary) hemangiomas and the superficial component of thin mixed-type hemangiomas respond best to pulsed dye laser therapy. Treat-ment of thin superficial hemangiomas can often clear these lesions in three to four treatment sessions (20,21,53–56). Thicker lesions may require additional treatments. The pulsed dye laser is also effective in reducing the superficial component of mixed-type hemangiomas; however, the deeper (cavernous) component may continue to proliferate despite laser therapy. Institution of pulsed dye laser therapy during the proliferative phase is helpful in slowing the growth of these lesions. Treatment of superficial hemangiomas helps in minimizing the enlargement of the tumor, prevents the development of complications such as bleeding and ulceration, and achieves improved cosmetic results. Treatment of proliferating hemangiomas is usually performed at two- to four-week intervals, in an effort to halt further tumor growth. The treatment interval for involuting hemangiomas is usually six to eight weeks. As with port wine stains, the newer 595-nm, 1.5-millisecond pulsed dye lasers, which can be used at higher fluences in conjunction with cryogen spray cooling, appear to achieve faster clearing of heman-giomas compared to historical controls, because of their ability to treat larger diameter and deeper blood vessels. The IPL has also been used 194 Kauvar for the treatment of superficial hemangiomas and the superficial compo-nent of mixed type hemangiomas with some success. Preliminary studies using millisecond-domain pulsed dye, diode, and Nd:YAG lasers show promising results with these wavelengths for thicker lesions. Telangiectasia Telangiectasia are capillaries, venules, or arteries that are 0.1 to 1.0mm in diameter and are visible as superficial cutaneous vessels. Facial telangiec-tasia are common, and in fair-skinned individuals, they are often asso-ciated with rosacea or actinic damage. Other etiologies include collagen vascular disease, genetic disorders, hormonal, primary cutaneous disease, and radiodermatitis. Spider angiomata are telangiectasia with a central feeding arteriole, typically appearing in preschool and school-age chil-dren with a peak incidence between the ages of 7 and 10. Most patients seek treatment for facial telangiectasia because of cosmetic concerns. Techniques used to treat facial telangiectasia have included electrosurgery, sclerotherapy, and treatment with continuous wave and quasi-continuous wave lasers, but these methods may produce textural and pigmentary irregularities. The development of pulsed lasers enabled efficient, effective, and low-risk treatment of these common skin lesions. A wide variety of vascular laser systems produce excellent clearance of facial telangiectasia. The 585- and 595-nm pulsed dye lasers with 0.45- and 1.5-millisecond pulse durations produce excellent results in one to two treatment sessions, but induce purpura lasting 7 to 14 days (37). Treatment is performed by applying contiguous laser pulses with approximately 10% overlap. The newer, millisecond-duration pulsed dye lasers, used at 6 to 10 milliseconds, clear facial telangiectasia, without purpura production. Effective treatment usually requires stacking of three to four laser pulses with an endpoint of vessel blanching or transient thrombosis. The 532-nm KTP laser produces excellent results for the treatment of facial telangiectasia in one to three treatment sessions (57,58). Contiguous laser pulses are applied directly over the vessels, with additional pulses, if necessary, to achieve visible vessel blanching. Some of the KTP systems are equipped with cooled sapphire hand pieces that enable easy gliding of the laser tip over the skin, when used with cold gel, and relatively painless treatment. Long-pulsed Nd:YAG lasers, used with spot sizes of 1 to 3mm and fluences of 120 to 250J/cm2, also produce excellent results for facial telangiectasia without purpura production. With the use of higher flu-ences, proper skin cooling and avoidance of pulse stacking are necessary to prevent epidermal damage, particularly around the nasal ala (46,59,60). The long-pulsed Nd:YAG lasers are particularly useful for the treatment of the larger caliber paranasal vessels that often require multiple, repetitive treatments with the shorter wavelength lasers. Venu-lectasia commonly seen on the lateral cheeks following rhytidectomy often usually clear in one treatment session. Visible facial veins have also ... - tailieumienphi.vn