Laser Resurfacing

Ablative lasers vaporize the entire upper layer of the skin and cause scabbing and crusting in post operative period. If combined with good postoperative care, they give the optimum results. The non ablative technology does not remove the upper epidermis, hence leaving no downtime and quick recovery. The term “partially ablative” is perhaps more useful for describing treatments in which some but not all of the epidermis is removed. These treatments are associated with an intermediate downtime of greater than 1 or 2 days, but less than 1 week. It is important to note that for a given device, the degree of “ablativeness” depends on multiple factors, including the fluence, repetition rate, and the degree of coverage of the device. Other factors including patient skin types and anatomic sites can also affect the depth of the treatment.

Following are the 2 main types of ablative lasers:

• A) CO2 LASER - The carbon dioxide (CO2) laser heralded a new era in the field of photorejuvenation. These first CO2 lasers operated using a continuous wave (CW). While providing skin enhancement, the rates of side effects were high, including undesirable scarring. To increase control of how much and what type of tissue would be removed, short-pulse CO2 lasers were developed. However, this technique was still ablative and retained a long 2-week recovery period. Two main types of CO2 lasers are in use today. The first is a high-power pulsed CO2 laser, which operates at 1 millisecond or less (Ultrapulse). The pulses can be used manually at a 3mm diameter or a computer pattern generator can be used. The second type uses the scanning of a CW CO2 laser (AcuPulse). Most of these scanning lasers are fractionated. This second category uses computerized controls to ensure that no individual area receives treatment more than once. The scanning CO2 lasers, as well as other pulsed CO2 lasers, produce equivalent results, side effects, and histologic differences. Both produce hypopigmentation equivalent to the efficacy of the treatment.
• B) ER: YAG LASER -The erbium-doped yttrium aluminum garnet (Er: YAG) laser emits light at the 2940nm wavelength in the infrared range whose wavelength is much closer to the peak absorption range of water and thus has an absorption coefficient 16 times greater than the CO2 laser. This greater absorption decreases the penetration depth into the epidermis by a factor of ten. This is an advantage, as more precise ablation of skin is possible with even less damage to surrounding tissue.

The ablative and non-fractionated lasers are more painful than non-ablative and fractionated lasers. A topical anaesthesia is generally applied for 30 to 60 minutes before procedures. Ablative lasers may require nerve blocks sometimes.

To understand this concept, let us look at the pixels that compose a tv image. The fractionated device treats only certain pixels while the non fractionated device treats every single pixel.

This class of lasers is aimed toward improving texture, mild to moderate wrinkles, and acne scarring as well as treating hyperpigmentation due to sun damage and aging. The neck, chest, and extremity regions are also safely and effectively respond to these lasers. These lasers are also effective in darker-skinned individuals with less risk of discoloration as they induce limited tissue damage and melanocyte stimulation. Treatment can be painful, and topic anesthetics help decrease patient discomfort. 1440 Nd: YAG laser and 1550 nm erbium Glass laser are few examples.

The recovery period depends on the type of laser and the depth of penetration. A CO2 laser may require upto 2 weeks of downtime while newer non-ablative lasers require less than a week or 3 to 4 days. A strict sun protection is mandatory along with usage of hydroquinone or glycolic agents required to prevent hyperpigmentation.