To prepare a patient for fractional photothermolysis with the FraxelrM laser (Reliant Technologies, Mountain View, CA), the skin should be washed with cleanser A lipid- based topical ane sthetic (e. g. 7 o/o ltdo caine / 7 o/o te tracainel is then applied for 45 minutes to I hour. Before laser treatment, the anesthetic is removed and a water-soluble blue dye (OptiGuiderM Blue, Reliant Technologies, Moun- tain View, CA) is applied in a thin layer to allow the laser's optical tracking system to detect contact and movement with the skin and adjust the pattern of microthermal treatment columns with respect to hand velocity The blue dye does not need to be applied in a uniform manner as the optical mouse detects differences in density of the
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blue dye on the skin's dermatogliphs. The blue dye is also detected at the center of the laser handpiece, which makes application close to the eyelid unnecessary
Another layer of either topical anesthetic ointment or petrolatum-based ointment is applied to help the hand- piece glide along the skin's surface Once the handpiece comes into contact n'ith the skin, it should be moved in a straight line consisting of one stroke until the end of the cosmetic unit is reached (Fig. z.l) The hand piece should then be retraced back over the same row to return to the starting point, completing two passes. Concomitant forced air cooling with the Zimmer device is useful to prevent bulk heating and achieve a greater degree of analgesra
The handpiece tip has markings that help guide the position of successive passes The first stroke of the third pass should be positroned either by overlapping the prior pass by 500/o or with no overlap. Again, when the end of the cosmetic unit is reached, the handpiece should be retraced back over the same row A 7 mm tio is available for use in the treatment of small areas such as the nasal b r i d g e o r p e r i o c u l a r s k i n .
After a cosmetic unit has been treated entirely with overlapping strokes from side to side, the direction of the rou.s should change by 90 degrees, and the process repeated from top to bottom. Each square centimeter of skin should end up with eight passes. If the 500/o overlap technique is used, then four to-and-fro motions are per- formed If the no-overlap technique is used, a total of six to-and-fro motions are performed. Thus, if the laser was set at 250 MTZ/clr'z, the end treatment density would be 2000MTZ/cm2 with approximately 5-8kJ of energy delivered over a ful1-face treatment. When the 500/o overlap technique is used, the edges of the treatment area will receive fewer passes because of the stroke pattern, providing a built-in feathering effect.
Fig. 2.5 Fractional photothermolysis treatment-the area is lightly coated with a water-soluble blue dye (OptiGuiderM Blue, Relianl Technologres, Mountain View, CA), which allows the laser's optical tracking system to detect contact and movemenl o{ the handpiece with the skin and adjust the pattern o{ microthermal treatmenl columns with respect to hand velocity
Ablative Laser Resurfacing ll
Treatment parameters can be adjusted according to the desired depth of injury The energy setting controls the depth of injury, while the density setting controls the percentage of skin that is treated (Fig. 2.6J . Therefore, for the treatment of superficial targets such as pigment, a typical course might consist of three to five treatments at low energies (8-10 mJ) and higher densities (2000- 3000 MTZlcm2) spaced 2-4 weeks apart For the treat- ment of deeper lesions such as acne scars, a typical course might consist of four to six treatments at higher energies [16-20 mJ with the Fraxel SR'M and 30-40 mJ with the Fraxel SR l500rM) and lower densities [1000-1500 MTZI cm2J spaced 2-4 weeks apart (Table z.z; Rahman et al
2006c1
A 'targeted'
treatment algorithm can be employed where higher energies are used in areas of deeper rhytides such as the perioral region and lower energies can be employed on the forehead and nose. This also increases patient comfort significantly during treatment Off-face resurfacing, except when treating for acne scars, should be treated at lower energies as well.
Treatment algorithms can be tailored to patients A 'lighter' treatment with less downtime requiring a great number of total treatments (five or more) can be used in patients who cannot tolerate any edema while a 'high- leve1' treatment with greater downtime and fewer total treatments (approximately four) can be used in those patients who can tolerate a few days of edema and ery- thema fRahman et al 2006dJ
Some comparative high- versus low-energy data with the FraxelrM laser shows improved results with higher energy treatments This is believed to be based on the concept of a larger volume of tissue treated at higher ener- gies allowing for deeper collagen remodeling
Treatments with the fractional Er:YAG lasers (1540nm Fractional Er:YAG, Palomar Medical Tech- nologies Inc., Burlington, MA and 1440 nm YAG laser, Af{rrmrM, Cynosure Inc., Westford MA) have been more recently described. Each appears to be somewhat less involved than FraxelrM treatments. Optical tracking is avoided, so the need for a skin colorant applied before the procedure is ehminated. In addition, topical anesthesia is only occasionally required, with reports ofthe procedures being more comfortable compared with the Fraxelrt laser resurfacing treatment. There have been no split-faced reports of pain scores comparing the various fractional devices at comparable energies
o Plasma skin regeneration
Patients undergoing PSR should arrive at least I hour beforehand so that a topical anesthetic cream can be applied to the treatment area. Patients undergoing high- energy treatments will require adjunctive oral analgesia and/or sedation
Generally, it is a good idea to work in esthetic seg- ments of the face [i e , forehead, nose, cheek, chin, etc ), removing the anesthetic cream for each area immediately
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Lasers and Lights Volume ll
Application
Melasma
Off-face resufacing
Mild-to-moderate rhytides. and pigmentation (Glogau ll-lll)
Severe rhytides.
and pigmentation (Glogau lV); scars-
Coverage (%)
1 0 1 0 1 4 22 1 0 - 1 4 1 4 - 1 9 22-29 1 0 - 1 4 't4-19 20-24
I J
1 8 24 1 5 1 9
Z J
1 4 - 1 6 19-22 24-27
Energy (mf)
6
8
8-1 0
8-1 0
1 2
t 3
z v - z ?
Treatment density (MTZIcm')
1 000 1 500 2000 1 500 2000 3000 1 500 2000 3000 1 500 2000 2s00 1 250 1 500 2000 1 000 1250 1 500
t 5 u
1 000 1250
Pass density (MTZIcm')
250 250 250 250 250 250 250 250 250 z5u 250 250 125 zau 250
t z J t z J
125 125 125 125
Number of passes
4 o 8 6 8 1 2
6 8 1 2
o 8
1 0 1 0
o
8 8 1 0 1 2
o
8 1 0
*Fraxel laser is FDA approved for periorbital rhytides, acne scars, and surgical scars.
before treating that area rather than removing the cream for the entire face at once Hvdration of the eoidermis has been found to influence the amount of energy atsorbed, so the physician should develop a protocol to standardize the delay time between removal of topical anesthesia and starting the procedure.
Topical anesthetic should be gently wiped off the segment to be treated with dry gauze. It is not necessary to use water- or alcohol-soaked gauze as this will change the hydration properties of the skin Once a faciai segment is ready for treatment, the tip of the handpiece should be held approximately 5 mm from the skin's surface (Fig.
z.Z) The pulses are delivered in a paint-brush fashion in rows of one direction (either all right to left or all left to right) because a zig-zag pattern has been found to cause heat buildup at the corners where one changes direction.
Pulses should not be overlapped more than approximately 100/0. Wet gauze should be placed over the patient's eyes,
brows, and hairline when working in adjacent areas. Fig. 2,6 Fractional photothermolysis treatment ranges for the Fraxel SRrM laser
Coverage Chart
3 5 3 0 2 5 20 1 5 1 0
0
T@tmant Density MfZl<m2 - f f i - . € 3 m
2 5 m
- 1 5 0 0
. 1250
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There are three recommended treatment guidelines, termed PSRI, PSR2, and PSR3 (Table z.l) The PSRI protocol uses a series of 1ow-energy treatments spaced 3 weeks apart The first treatment is performed at 7.0-7.2 J, and energies are increased as tolerated at subsequent visits Recovery time is 3-4 days. The PSRI protocol is a good choice for those with mild-to-moderate photodam- age or those who cannot tolerate more than a few days of healing time The PSR2 protocol uses one hlgh-energy pass (3 0-4.0 J) with a recovery time of 5-7 days, and the PSR3 protocol uses two high-energy passes (3.0-4.0J) with a recovery time of 6-10 days. The PSRZ protocol is a good choice for those with moderate photooamage, while the PSR3 protocol is a good choice for those with moderate-to-severe photodamage and those who desire a greater degree of skin tightening. A series of treatments in the mid-energy group (1.5-3.0J) has good results in improving skin texture and discoloration, but has only slightly less recovery time than a single high-energy treat- ment. Therefore, most practitioners prefer to use the suggested PSRl, 2, or 3 protocols.
To avoid lines of demarcation with the high-energy protocols, the borders of the treatment area should be feathered by increasing the distance of the nozzle from the surface of the skin to approximately I cm. Feathering can also be achieved by holding the handpiece nozzle at an angle with respect to the skin surface or reducing the power setting There is no need for feathering in the 1ow- energy PSRI protocol.