Laser treatment of vascular lesions requires a complete understanding of the various cutaneous vascular diseases as well as the means by which they can be treated using laser technology. Once previously considered untreatable, cutaneous vascular lesions of the head and neck can cause significant morbidity and facial deformity. The use of lasers in the treatment of these lesions has become a historic step in the fields of both facial plastic surgery and applied laser technology.

The word LASER is an acronym for “light amplification by the stimulated emission of radiation,” as proposed in Albert Einstein’s landmark 1917 article, “Quantum Theory of Radiation.” In 1963, Solomon et al. introduced the use of lasers for the medical management of cutaneous vascular lesions, such as port-wine stains (PWS) and cavernous hemangiomas. By the early 1980s, laser therapy became the first effective treatment for PWS based upon the work of Anderson and Parrish and their theory of selective photothermolysis. This theory describes how light energy is used to target a specific light-absorbing chromophore residing at a particular depth within tissue while not injuring normal adjacent structures. Target selectivity is based upon each chromophore’s preferential absorption of a light at a specific wavelength(s). The overall parameters of laser therapy depend upon light wavelength, pulse duration, and energy density used. This is of critical importance as the precise control of thermal energy/injury is just as important as optical and tissue factors. One measure to maximize the spatial confinement of heat is to use a laser with pulse duration on the order of the thermal relaxation time (T_r) of the target chromophore. T_r is defined as the time required for the heat generated by the absorption of energy within the target chromophore to cool to 50% of the original value immediately after the laser pulse. During longer laser exposures, a more generalized heating, and less spatial selectivity, are produced and result in nonspecific thermal damage to adjacent structures. However, if the laser pulse is suitably brief, the energy is invested in the target chromophore before thermal diffusion extends out of the exposure field. Simply stated, shorter laser pulse durations confine the energy to smaller target regions with more spatial selectivity and less collateral damage.

The final consideration in selective photothermolysis is energy density, defined as transmitted light energy per unit area. The absorption of light in a specific region is attenuated by competing chromophores as well as the normal scattering of the optical beam. These factors must be considered in order to achieve an energy density adequate to induce selective destruction of the targeted chromophore/region. Additionally, the effect of spot size on energy density is an inverse and squared relationship. If the spot size is decreased by a factor of two, energy density increases by a factor of four. In similar fashion, doubling of the laser spot size results in a fourfold reduction in energy density.

With these central concepts in mind, there are a variety of lasers approved by the Food and Drug Administration (FDA) for the treatment of cutaneous vascular lesions. Recognition and understanding of the most common devices provides a necessary foundation for appropriate clinical therapy.

A complete general history is a requisite for each patient undergoing laser therapy. The history should include the location, dimensions, and duration of each lesion, as well as the growth rate and previous interventions undertaken. It is also important to identify any symptoms attributable to the lesions including mass effect, bleeding, sensation change, and pruritus. Specific attention must be paid to any direct or family history of similar lesions as well as aberrant scarring (i.e., hypertrophic scar or keloid formation), dermatologic diseases (e.g., allergic, immunologic, inflammatory), allergies, past complications in wound healing, degree of sun exposure, bleeding disorders, and prior skin procedures or surgery over the area to be treated. Complicating factors for wound healing, such as smoking, diabetes, and use of the isotretinoin should also be identified.

Approximately 60% of all vascular tumors and malformations involve the region of the head and neck. Vascular tumors, such as hemangiomas, are benign proliferations of endothelial cells found within the skin or mucosa with a spontaneous regression rate of 40% over a 12-year period. Vascular malformations, by comparison, originate from congenitally dysmorphic vessels that hypertrophy and never involute. Based on the vasculature involved, malformations are anatomically classified based on the prevailing vessel—capillary, lymphatic, venous, or arterial. These may be further divided into high- or low-flow lesions. Since these malformations occur during embryogenesis, vascular malformations may include combined channels (e.g., arteriovenous malformations). For clinical and therapeutic reasons, it is important to determine the classification of the vascular lesions being evaluated (Fig. 31.2).