Chapter 35: Ablative and Fractional Ablative Resurfacing

INTRODUCTION

Laser resurfacing began in the 1980s with fully ablative (confluent) skin resurfacing to address cosmetic concerns of aging skin. Chronologic aging contributes to deteriorating skin texture and tone. This process is exacerbated by years of ultraviolet light exposure leading to photodamage in the form of lentigines, rhytides, texture irregularity, and telangiectasia. Traditional resurfacing was first performed with a 10,600 nm carbon dioxide (CO₂) laser and later evolved with the 2940 nm erbium-doped yttrium aluminum garnet (Er:YAG) laser either as a short pulse after CO₂ laser or alone as a long-pulsed Er:YAG laser.

CO₂ laser resurfacing is based on the theory of selective photothermolysis.^1,2 Briefly, selective photothermolysis allows for the selective targeting of a chromophore by choosing a specific wavelength and appropriate pulse duration for that chromophore. The 10,600 nm wavelength specifically targets water as the primary chromophore to completely ablate the epidermis and the superficial dermis. A fluence of 5 J/cm² has been determined to be necessary to vaporize epidermal cells. The delivered energy must be within the thermal reaction time of the target, which is less than 1 ms for epidermal cells. The re-epithelialized skin has a more youthful appearance with improved texture and tone. For decades, fully ablative CO₂ lasers were considered the gold standard in skin resurfacing for rhytides, photodamage, and scars.^3–5 The results seen with traditional resurfacing are predictable and successful, but coincide with a risk of scarring, dyspigmentation, and prolonged downtime dependent on the extent of nonspecific thermally damaged tissue remaining after tissue vaporization. As a result, alternative approaches to circumvent the side-effect profile of traditional CO₂ and Er:YAG lasers were developed.

The nonablative laser-resurfacing devices that appeared on the market were initially met with great enthusiasm, but quickly fell out of favor due to marginal clinical improvement.^6,7 Nonablative technology was significantly advanced in 2004 with the introduction of fractional photothermolysis.⁸ In fractional photothermolysis, the laser beam is pixilated, delivering the energy to only a specific fraction of the epidermal and dermal architecture. The undamaged intervening areas of skin allow for more rapid healing and an improved side-effect profile. The first laser to employ this technology was a 1550 nm erbium-doped fiber laser. Although fractional nonablative devices showed more improvement than traditional nonablative devices, the results were still less impressive compared to ablative resurfacing and required a series of treatments.⁹ This led to the development of fractional ablative devices. Fractional ablative resurfacing produces significantly better clinical results than those seen with nonablative technologies and approaches but does not achieve the results seen with fully ablative resurfacing. Significant clinical improvement, along with decreased downtime and an enhanced safety profile, has advanced the adoption of fractional ablative lasers. This chapter will review the indications, patient selection, perioperative management and anesthesia, and complications for traditional ablative and fractional ablative lasers.

ABLATIVE LASERS