YSGG 2790-nm Superficial Ablative and Fractional Ablative Laser Treatment




The 2790-nm wavelength YSGG laser was introduced for aesthetic purposes under the trade name Pearl by Cutera in 2007. In clinical use, the Pearl superficial resurfacing laser has proved effective and well tolerated for the correction of superficial brown epidermal dyschromia and superficial fine lines and scars, and the Pearl Fractional laser produces excellent improvement in both dyschromia and improvement of deeper lines and moderately deep acne scarring. The two laser treatments can be combined in a single treatment session on different parts of the face or on the entire face, depending on patient needs and priorities.


The 2790-nm wavelength yttrium-scandium-gallium-garnet (YSGG) laser was introduced for aesthetic purposes under the trade name, Pearl, by Cutera in 2007. Like 10,600-nm CO 2 and 2940-nm erbium:yttrium-aluminum-garnet (Er:YAG) ablative resurfacing lasers, the YSGG 2790 nm uses as its chromophore water in the top 1 mm of the skin ( Fig. 1 ).




Fig. 1


Absorption of energy by water as a function of wavelength. Energy from the 10,600-nm CO 2 laser has a low coefficient of absorption by water of approximately 1000, which produces a high amount of coagulation in proportion to ablation. 2790-nm (YSGG) laser energy has an intermediate coefficient of absorption of approximately 5000, which produces a balanced amount of ablation in proportion to coagulation. 2940-nm (Er:YAG) laser energy has a high coefficient of absorption at approximately 12,500, causing a high amount of ablation in proportion to coagulation. In some Er:YAG systems, the initial short ablative pulse of the Er:YAG is followed by 1 or more longer, lower-powered coagulative pulses (see Fig. 2 ), giving a final balance between ablation and coagulation approximating that produced by the YSGG laser (see Fig. 3 ).


YSGG 2790 nm was chosen by Cutera because it was considered to produce a better blend of coagulation and ablation than the CO 2 laser, which deposits a large amount of coagulation-causing thermal energy in the skin for a given amount of ablation, or the Er:YAG laser, which deposits little thermal energy in the skin for a given amount of ablation ( Fig. 2 ). Some Er:YAG lasers can be made to produce a train of subpulses, which, at appropriate parameters, can produce a greater degree of coagulation in proportion to ablation ( Fig. 3 ), so approximate the ratio of ablation to coagulation created by the YSGG. All 3 types of fractional lasers are capable of penetrating more than 1 mm into the skin.




Fig. 2


The relative sizes of the zones of coagulation in this schematic diagram are shown in red. Note that in some variants of fractional ablative Er:YAG laser systems, 1 or more lower-powered coagulative pulses, which are nonablative, follow the initial ablative pulse, and the effect of this series of pulses approximates the ablation/coagulation balance of the YSGG laser.



Fig. 3


The addition of a subablative pulse after the ablative pulse gives some Er:YAG systems an improved ratio of coagulation to ablation.


During fractional resurfacing, thermal energy is useful to the extent that it turns on repair and remodeling systems in the skin and coagulates blood vessels to limit pinpoint bleeding. Too much thermal energy can cause a burn, with attendant risks of scarring, pigment loss, and prolonged healing. Not enough thermal energy can result in reduced skin tightening and remodeling and troublesome pinpoint bleeding during the procedure.


In clinical use, the Pearl superficial resurfacing laser has proved effective and well tolerated for the correction of superficial brown epidermal dyschromia and superficial fine lines and scars, and the Pearl Fractional laser produces excellent improvement in both dyschromia and improvement of deeper lines and moderately deep acne scarring. The 2 laser treatments can be combined in a single treatment session, either on different parts of the face or on the entire face, depending on a patient’s needs and priorities ( Fig. 4 ).




Fig. 4


There are 2 Pearl YSGG 2790-nm laser systems, one optimized for superficial resurfacing and the other for fractional ablative resurfacing. Either or both systems can be used in a single treatment session, depending on a patient’s needs and priorities.


The risks of treatment using the YSGG lasers are similar to other ablative and fractional ablative resurfacing lasers. The risk of bulk heating, which can cause scarring and pigment loss, seems to be lower with YSGG than in CO 2 fractional ablative lasers and perhaps lower than Er:YAG fractional ablative systems when they are operated with a high level of coagulation. Scarring and pigment loss have been reported after fractional CO 2 laser but as of late 2010 not with Pearl fractional YSGG, probably because the Pearl Fractional ablative system delivers a lower thermal load to the skin. All fractional ablative lasers can occasionally cause superficial pitting of the skin ( Fig. 5 ), and this can persist for many months after treatment and occasionally is permanent. The cause of this pitting has not been determined, and an effective treatment protocol for it has not been defined. The risk of pitting may increase with spot size.




Fig. 5


Female patient before ( left ), and 7 weeks after ( middle ) YSGG fractional ablative laser resurfacing, illustrating pitting of the skin. Patient was treated a second time with YSGG fractional ablative laser resurfacing at low fluence [60 mJoules] and high density (5), three passes, and had marked resolution of pitting ( right ) at five months after the second procedure.


Actual use of YSGG lasers


The Consultation


When considering the range of treatments a patient might benefit from, YSGG superficial resurfacing laser comes into play with patients who have brown epidermal dyschromia and/or fine lines or superficial acne scarring Fig. 6 . Such patients might benefit from a series of 3 to 6 intense pulsed light treatments but might benefit more (and with only 1 or 2 treatments) from YSGG resurfacing.




Fig. 6


Woman with brown dyschromia and superficial fine lines and acne scarring before and after Pearl resurfacing.


Patients need to understand that it took several years for their skin to get to the point where corrective treatment was needed, and patients need to allow approximately 4 to 5 days for sunburn-like social downtime, after which makeup can usually be worn, plus another week or two of somewhat pink skin ( Fig. 7 ). Usually, the greatest degree of inflammation and erythema occurs at 48 to 72 hours after treatment. Patients should expect that they usually see improvement by approximately 3 weeks, and maximum improvement is reached by 3 to 6 months after treatment.


Sep 2, 2017 | Posted by in General Surgery | Comments Off on YSGG 2790-nm Superficial Ablative and Fractional Ablative Laser Treatment

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