INTRODUCTION
PWS, also regarded as “nevus flammeusâ€, are benign congenital vascular malformations consisting of ectatic
blood vessels, situated predominantly in the upper
dermis.1 Unlike hemangioma, PWSs do not have a tendency
to involute. These birthmarks occur in 0.3% to 0.5% of newborns and initially appear as flat, pink to red patches that may gradually progress into hypertrophic, red to purple lesions with age.2-4 Histologically, PWS demonstrate ectatic dilation of a normal number of post capillary venues of diameters
ranging from 10 to 150 μm and predominantly involve the papillary dermis.5, 6 They commonly occur on the head and neck (83%),7 which can be associated with significant cosmetic disfigurement and psychological distress, especially
when involving these exposed areas.8,9 So early treatment is recommended.
Although PDL is still the mainstay of treatment for majority of PWSs, not all lesions respond well. Complete clearance is achieved in < 10%, and roughly 20% of lesions fail to lighten at all.10 In some patients, PWSs become refractory to PDL. Limited
penetration depth of yellow light emitted by PDL may well explain
this. The depth of PWS ranges from 1 to 5 mm, which cannot be reached alone by 595-nm PDL.11 In order to improve outcomes in advanced deep red or purple PWS or even with overlying nodularity, treatment with a more deeply penetrating
millisecond-pulsed 1,064-nm Nd: YAG laser has been studied.12,13 However this wavelength has less hemoglobin absorption; thus, higher laser fluences are required to achieve adequate capillary heating. Additionally, the laser has a narrow
therapeutic window, which may result in increasingly risk of epidermal and dermal side effects, such as unacceptable
scarring. In order to improve efficacy and minimize side effects, hybrid lasers were advocated. Some research have found that combined PDL and Nd: YAG laser were effective for PWSs.14,15 However, controlled split-face clinical trials of PWSs treated with dual-wavelength laser are rare in literatures. The objective of this clinical study was to evaluate the efficacy and safety of a novel device that delivers sequential timed pulses of 595- and 1,064-nm wavelengths through a single handpiece in the treatment of neck and facial PWSs in Chinese patients.