Nonablative technology for treatment of aging skin 63Table 6.5 Studies of the use of radiofrequency RF for skin tightening patients J/cm 2 treated Efficacy effects months 73 40 — Face,
Trang 1sequentially through a bipolar electrode tip with
epidermal cooling Three treatments were given at
3-week intervals to 20 patients with mild to moderate
rhytids and skin laxity Optical and RF fluences ranged
from 30 to 40 J/cm2and from 50 to 85 J/cm3,
respec-tively The prospective study showed a mean clinical
improvement of superficial rhytids at 6 months of
1.63/4 For skin laxity of the jowl and cheek,
improve-ment scores reached 2.00/4 at 6 months Patient
assessments were similar Side-effects were mild In a
combined study62of ELOS with both IPL and a diode
laser (Fig 6.8), overall effectiveness scores in multiple
measures of photodamage was approximately 26%
NONABLATIVE TECHNOLOGIES FOR
SKIN TIGHTENING
From the evidence that collateral heating of the dermis
while targeting vascular and pigmented lesions created
new collagen and decreased wrinkles sprang the idea of
bulk dermal heating Bulk dermal heating requires
rela-tively deep energy deposition over a period of seconds
as opposed to microseconds, with cooling to protect
the epidermis.The intent of tissue tightening is to
actu-ally lift or firm tissue in a three-dimensional manner
This is not the same as stimulating collagen to fill in
superficial scars or wrinkles, but a deeper shift in tissue
volumes, leading to a remodeling of the entire softtissue envelope, a completely new aesthetic capability.Collagen fibers consist of protein chains held in atriple helix When collagen is heated, non-colaventbonds linking the protein strands together are rup-tured, producing an amorphous arrangement of ran-domly coiled chains.63As the chains rearrange, fibers
of the denatured collagen become shorter and thicker.Heat-induced contraction of collagen and long-termfibroblastic stimulation are is the basis for the treat-ment of skin laxity.64
For exposures lasting several seconds, the denaturationtemperature of collagen has been estimated at 65°C.65,66
In practice, however, collagen denaturation has a complexdependence on temperature described by the Arrheniusreaction-rate equation.This relationship may not hold forvery short time exposures to heat, because the kinetics ofcollagen denaturation are not known.66
There are two technologies supported by reviewed literature at present for evaluation: RF andbroadband infrared (IR) light
peer-Radiofrequency-based tissue tightening
RF energy interacts with tissue to generate a current
of ions that, when passed through tissues, encountersresistance This resistance, or impedance, generates
62 Clinical procedures in laser skin rejuvenation
Fig 6.9 Partially denatured collagenafter Thermage treatment as 160microns by electron microscopy
(Reproduced courtesy of Dr BrianZelickson and Thermage Corp.)
Trang 2Nonablative technology for treatment of aging skin 63
Table 6.5 Studies of the use of radiofrequency (RF) for skin tightening
patients (J/cm 2 ) treated Efficacy effects (months)
73 40 — Face, 70% of patients Moderate pain 1, 2, 3
anterior noticed significant during treatment;
neck improvement in 3/40 patients
skin laxity and experienced texture at 3 months superficial blistering
74 15 52 (only Face 14/15 patients responded; Minimal 6–14
for 2 nasolabial folds: 50% of discomfort patients patients had at least 50% during treatment treated with improvement; cheek contour: in all patients;
1 cm 2 tip) 60% had 50% improvement; superficial
mandibular line: 27% had at burn (1 patient) least 50% improvement;
marionette lines: 65% had
at least 50% improvement.
69 86 58–140 Periorbital Fitzpatrick wrinkle scores Minimal erythema, 6
wrinkles, improved by 1 point or edema, 2nd-degree brow more in 83.2% of patients; burn; small residual position) 50% of patients satisfied scar at 6 months in
to very satisfied; 61.5% of 3 patients eyebrows lifted by 0.5 mm
70 16 — Cheeks, jaw 5 of 15 patients contacted Mild, transient 6
line, upper neck were satisfied with results erythema and edema
78 17 125–144 Brow, jowls, Gradual tightening Mild, temporary 4
nasolabial folds, erythema puppet lines
75 50 97–144 Mild to Significant improvement Mild and temporary 6
(cheeks) moderate in most patients; patient edema, erythema, 74–110 skin laxity satisfaction was similar rare dysesthesia (neck) in neck to observed clinical
and cheek improvement
68 24 — Upper third Objective data showed Pain during 4–14 weeks
of face; brow non-uniform (asymmetric) treatment;
elevation; improvement; patient redness forehead, satisfaction low; 72.7%
temporal said they would not have regions the procedure again;
results not predictable
57 7 73.5 Face; laxity, About 16% median None 2–6
wrinkles, pores, improvement in wrinkles pigmentation, and skin laxity; about 16%
texture improvement in texture,
pores, and pigmentation;
patients satisfied; improvement maintained 2–6 months
Trang 3heat in proportion to the amount of impedance.
Tissues with high impedance will be heated more than
tissues of low impedance.67
Traditional RF devices used in skin surgery deliver
therapeutic energy through the tip of an electrode
in contact with skin The concentrated thermal
energy produces heat at the surface of the skin, which
injures both the dermis and epidermis.68To reduce
heat-induced epidermal injury while heating the
der-mis, developed the ThermaCool, a device that delivers
RF energy to the skin via a thin capacitive coupling
membrane that distributes RF energy over the tissue
volume beneath the membrane’s surface (rather than
concentrating the RF energy at the skin surface) while
cooling the epidermis by cryogen spray.69,70Although
the deep dermal layer can theoretically reach
tempera-tures exceeding 65°C, permitting the heat-sensitive
collagen bonds to go beyond their 60° denaturationthreshold, the temperature of the epidermis is main-tained between 35°C and 45°C.68A study of the histo-logical and ultrastructural effects of RF energysuggested that collagen fibrils contract immediatelyafter treatment and that production of new collagen isinduced by tissue contraction and heat-mediatedwounding (Fig 6.9).71
The first clinical study of the ThermaCool assessedskin contraction, gross pathology, and histologicalchanges for a range of RF doses.70,72 Iyer et al73
reported that 70% of patients noticed skin laxityimprovement 3 months after a single RF treatment andthat improvement increased with additional treat-ments A subsequent report described a prototypedevice designed to produce heat in the dermal layer oftissue while protecting the epidermis by cryogen spray
64 Clinical procedures in laser skin rejuvenation
Fig 6.10 Before (a) and 8 months after (b) tissue tightening treatments: one radiofrequency treatment on the left side of theface and two broadband infrared light device treatments on the right Note the decreased depth of the nasolabial folds andmarionette lines, the firming of the skin over the mid cheek and the restoration of the shape of the face toward an oval, instead of
a rectangle (Photographs courtesy of Amy Forman Taub MD.)
Trang 4cooling.74Of the 15 patients,14 responded to a single
treatment without wounding or scarring Pain was
used to indicate the tolerability of treatment Patients
resumed normal activities immediately after
treat-ment
Other RF studies that followed are summarized in
Table 6.5 In each study, patients had a single
treat-ment, local anesthesia was used during treattreat-ment, and
results were evaluated by comparing pre- and
post-treatment photographs Improvements with a single
treatment were gradual and subtle and lasted for
sev-eral months Higher fluences were required with thick
skin.69When low fluences were used, improvements
were less pronounced.70,75
Initially, it was believed that the highest fluences
would yield the best results However, this was
accom-panied by significant patient discomfort and a
rela-tively high rate of significant side-effects,76 such as
scars and changes in skin surface textures (e.g.,
inden-tation or waffling) A different model based on a
lower-fluence, multiple-pass protocol was shown via
ultrastructural analysis of collagen fibril architecture
to provide much more collagen deposition deeper in
the dermis than the high-fluence protocol.77This is
believed to yield more consistent results, higher
patient tolerability, and fewer complications Recent
advances include specialized tips for more superficial
areas (eyelids) and body areas (arms and abdomen)
Infrared light-based tissue tightening
A broadband infrared light tightening device hasrecently been developed as an alternative technologyfor tissue tightening (Titan, Cutera, Brisbane, CA).This generates energy of up to 50 J/cm2 energy at1100–1800 nm wavelengths, with pre- and postcool-ing being built into the multisecond pulse The longwavelengths of near- and mid-IR radiation offer threemajor advantages over shorter wavelengths: (1) deeperpenetration into the dermal layer (2) less absorption
by melanin, and (3) reduced risk in dark-skinnedpatients.56This device targets the dermis at a depth of1–2 mm, which is more superficial than the RF device.The author has found this to be an advantage for thin-ner skin, whereas the RF technology may be better forthicker skin with more subcutaneous tissue attached –but these observations are anecdotal However, inmany skin types, the results may be similar (Fig 6.10).Studies of the use of infrared light in tissue tighteningare summarized in Table 6.6
THE FUTURE AND CONCLUSIONS
A major advantage of nonablative techniques is thattreatment requires little or no downtime for patients.The importance of this feature is evident from the
Nonablative technology for treatment of aging skin 65
Table 6.6 Studies of the use of broadband infrared (IR) light for skin tightening
Device
No of (No of Fluence Local Treatment Adverse Follow-up Ref patients treatments) (J/cm 2 ) anesthesia target Efficacy effects (months)
79 25 1100– 20–40 For first 5 Forehead; Immediate Small Up to 12
1800 nm patients lower improvement in 22 burns (1–3) face and patients, persisted
neck for follow-up period;
all patients satisfied
80 42 1100– 30–38 Sometimes Face, Improvement Transient 4
(2) abdomen higher in 52.4% swelling
of patients and
erythema, rare blister
Trang 5growth and proliferation of nonablative devices since
they were introduced in the late 1990s Disadvantages
are that efficacy is modest and multiple treatments are
required to achieve results Future efforts will be
focused on increasing efficacy and reducing the
num-ber of treatments, making treatment more affordable
for more patients
REFERENCES
1 Fitzpatrick R, Rostan E, Marchell N Collagen tightening
induced by carbon dioxide laser versus erbium:YAG laser.
Lasers Surg Med 2000;27:395–403.
2 Nelson J, Majaron B, Kelly K What is nonablative
photorejuvenation of human skin? Semin Cutan Med Surg 2002;21:238–50.
3 Grema H, Greve B, Raulin C Facial rhytids –
subsurfac-ing or resurfacsubsurfac-ing? A review, Lasers Surg Med 2003;32:
405–12.
4 Herne K, Zachary C New facial rejuvenation techniques.
Semin Cutan Med Surg 2000;19:221–31.
5 Ross E, Sajben F, Hsia J,et al Nonablative skin
remodel-ing: selective dermal heating with a mid-infrared laser and contact cooling combination Lasers Surg Med 2000;
26:186–95.
6 Kelly K, Nelson J, Lask G, Geronemus R, Bernstein L.
Cryogen spray cooling in combination with nonablative laser treatment of facial rhytids Arch Dermatol 1999;
135:691–4.
7 Goldberg D Full-face nonablative dermal remodeling
with a 1320 nm Nd:YAG laser Dermatol Surg 2000;
26:915–18.
8 Goldberg D New collagen formation after dermal
remodeling with an intense pulsed light source J Cutan Laser Ther 2000;2:59–61.
9 Trelles M, Allones I, Luna R Facial rejuvenation with a
nonablative 1320 nm Nd:YAG laser: a preliminary clinical and histologic evaluation Dermatol Surg 2001;
27:111–16.
10 Fournier N, Dahan S, Barneon G, et al Nonablative
remodeling: a 14-month clinical ultrasound imaging and profilometric evaluation of a 1540 nm Er:Glass laser.
Dermatol Surg 2002;28:926–31.
11 Bitter P Noninvasive rejuvenation of photodamaged skin
using serial, full-face intense pulsed light treatments.
Dermatol Surg 2000;26:835–42.
12 Weiss R, McDaniel D, Geronemus R, Weiss M Clinical
trial of a novel non-thermal LED array for reversal of photoaging: clinical, histologic, and surface profilometric results Lasers Surg Med 2005;36:85–91.
13 Zelickson B, Kilmer SL, Bernstein E, et al Pulsed dye laser therapy for sun damaged skin Lasers Surg Med 1999;25:229–36.
14 Rostan E, Bowes L, Iyer S, Fitzpatrick R A double-blind, side-by-side comparison study of low fluence long pulse dye laser to coolant treatment for wrinkling of the cheeks J Cosmet Laser Ther 2001;3:129–36.
15 Lee M Combination 532-nm and 1064-nm lasers for noninvasive skin rejuvenation and toning Arch Dermatol 2003;139:1265–76 [Erratum: 2004;140:625].
16 Menaker G, Wrone D, Williams R, Moy R Treatment of facial rhytids with a nonablative laser: a clinical and histo- logic study Dermatol Surg 1999;25:440–4.
17 Goldberg D Non-ablative subsurface remodeling: clinical and histologic evaluation of a 1320-nm Nd:YAG laser.
J Cutan Laser Ther 1999;1:153–7.
18 Sadick N, Alexiades-Armenakis M, Bitter P Jr, Hruza G, Mulholland R Enhanced full-face skin rejuvenation using synchronous intense pulsed optical and conducted bipolar radiofrequency energy (ELOS): introducing selective radiophotothermolysis J Drugs Dermatol 2005; 4:181–6.
19 Goldberg D, Amin S Russell B,et al Combined 633-nm and 830-nm LED treatment of photoaging skin J Drugs Dermatol 2006;5:748–53.
20 Manstein D, Herron G, Sink R, Tanner H, Anderson R Fractional photothermolysis: a new concept for cuta- neous remodeling using microscopic patterns of thermal injury Lasers Surg Med 2004;34:426–38.
21 Weiss R,Weiss M, Beasley K, Munavalli G Our approach
to non-ablative treatment of photoaging Lasers Surg Med 2005;37:2–8.
22 Geronemus R Fractional photothermolysis: current and future applications Lasers Surg Med 2006;38:169–76.
23 Kauvar A, Rosen N, Khrom T A newly modified 595-nm pulsed dye laser with compression handpiece for the treatment of photodamaged skin Lasers Surg Med 2006;38:808–13.
24 Bjerring P, Clement M, Heickendorff L, Egevist H, Kiernan M Selective non-ablative wrinkle reduction by laser J Cutan Laser Ther 2000;2:9–15.
25 Tanghetti E, Sherr E, Alvarado S Multipass treatment of photodamage using the pulse dye laser Dermatol Surg 2003;29:686–90.
26 Hsu T, Zelickson B, Dover J, et al Multicenter study of the safety and efficacy of a 585 nm pulsed-dye laser for the nonablative treatment of facial rhytids Dermatol Surg 2005;31:1–9.
27 Goldberg D, Cutler K Nonablative treatment of rhytids with intense pulsed light Lasers Surg Med 2000;26: 196–200.
28 Negishi K, Tezuka Y, Kushikata N, Wakamatsu S Photorejuvenation for Asian skin by intense pulsed light Dermatol Surg 2001;27:627–631; discussion 632.
66 Clinical procedures in laser skin rejuvenation
Trang 629 Huang Y, Liao Y, Lee S, Hong H Intense pulsed light for
the treatment of facial freckles in Asian skin Dermatol Surg 2002;28:1007–12.
30 Goldberg D, Samady J Intense pulsed light and Nd:YAG
laser non-ablative treatment of facial rhytids Lasers Surg Med 2001;28:141–4.
31 Sadick N, Weiss R, Kilmer S, Bitter P Photorejuvenation
with intense pulsed light: results of a multi-center study.
J Drugs Dermatol 2004;3:41–9.
32 Brazil J, Owens P Long-term clinical results of IPL
photorejuvenation J Cosmet Laser Ther 2003;5:168–74.
33 Kligman D, Zhen Y Intense pulsed light treatment of
photoaged facial skin Dermatol Surg 2004;30:1085–90.
34 Carniol P, Farley S, Friedman A Long-pulse 532-nm
diode laser for nonablative facial skin rejuvenation Arch Facial Plast Surg 2003;5:511–13.
35 Tan M, Dover J, Hsu T, Arndt K, Steward B Clinical
eval-uation of enhanced nonablative skin rejuvenation using a combination of a 532 and a 1,064 nm laser Lasers Surg Med 2004;34:439–45.
36 Butler E, McClellan S, Ross E Split treatment of
photo-damaged skin with KTP 532 nm laser with 10 mm piece versus IPL: a cheek-to-cheek comparison Lasers Surg Med 2006;38:124–8.
hand-37 McDaniel D,Weiss R, Geronemus R, Ginn L, Newman J.
Light-tissue interactions I: Photothermolysis vs lation laboratory findings Lasers Surg Med 2002;14:25.
photomodu-38 Weiss R, Weiss M, Geronemus R, McDaniel D A novel
non-thermal non-ablative full panel LED tion device for reversal of photoaging: digital microscopic and clinical results in various skin types J Drugs Dermatol 2004;3:605–10.
photomodula-39 Russell B, Kellet N, Reilly L Study to determine the
effi-cacy of combination LED light therapy (633 nm and
830 nm) in facial skin rejuvenation J Cosmet Laser Ther 2005;7:196–200.
40 Nestor M, Gold M, Kauvar A, et al The use of
photody-namic therapy in dermatology: results of a consensus conference J Drugs Dermatol 2006;5:140–154.
41 Ruiz-Rodriguez R, Sanz-Sanchez T, Cordoba S
Photo-dynamic rejuvenation, Dermatol Surg 2002;28:742–4.
42 Touma D,Yaar M, Whitehead S, Konnikov N, Gilchrest
BA A trial of short incubation, broad-area photodynamic therapy for facial actinic keratoses and diffuse photodam- age Arch Dermatol 2004;140:33–40.
43 Lowe N, Lowe P A pilot study to determine the efficacy
of ALA–PDT photorejuvenation for the treatment of facial ageing J Cosmet Laser Ther 2005;7:159–62.
44 Hall J, Keller P, Keller G Dose response of combination
photorejuvenation using intense pulsed light-activated photodynamic therapy and radiofrequency energy Arch Facial Plast Surg 2004;6:374–8.
45 Bhatia A, Dover J, et al Adjunctive use of topical levulinic acid with intense pulsed light in the treatment
amino-of photoaging Paper presented at: Controversies and Conversations in Cutaneous Laser Surgery, Mt Tremblant, Canada, August 2004.
46 Gold M, Bradshaw V, Boring M, Bridges T, Biron J face comparison of photodynamic therapy with 5- aminolevulinic acid and intense pulsed light versus intense pulsed light alone for photodamage Dermatol Surg 2006;32:795–801.
Split-47 Dover J, Bhatia A, Stewart B, Arndt K.Topical vulinic acid combined with intense pulsed light in the treat- ment of photoaging.Arch Dermatol 2005;141:1247–52.
5-aminole-48 Gold M Intense pulsed light therapy for tion enhanced with 20% aminolevulinic acid photody- namic therapy J Lasers Med Surg 2003; 15(Suppl):47.
photorejuvena-49 Goldman M, Atkin D, Kincad S PDT/ALA in the ment of actinic damage: real world experience J Lasers Med Surg 2002;14(Suppl):24.
treat-50 Avram D, Goldman M, Effectiveness and safety of ALA– IPL in treating actinic keratoses and photodamage.
J Drugs Dermatol 2004;3(1 Suppl):S36-S39.
51 Alster T,Tanzi E,Welsh E Photorejuvenation of facial skin with topical 20% 5-aminolevulinic acid and intense pulsed light treatment: a split-face comparison study.
J Drugs Dermatol 2005;4:35–8.
52 Lupton JR,Williams CN,Alster TS Nonablative laser skin resurfacing using a 1540 nm erbium glass laser: a clinical and histologic analysis Dermatol Surg 2002;28:833–5.
53 Fournier N, Mordon S Nonablative remodeling with
a 1,540 nm erbium:glass laser Dermatol Surg 2005;31: 1227–35.
54 Lee M Combination visible and infrared lasers for skin rejuvenation Semin Cutan Med Surg 2002;21:288–300.
55 Tanzi E, Williams C, Alster T Treatment of facial rhytids with a nonablative 1,450-nm diode laser: a con- trolled clinical and histologic study Dermatol Surg 2003;29:124–8.
56 Dayan SH, Vartanian AJ, Menaker G, Mobley SR, Dayan
AN Nonablative laser resurfacing using the long-pulse (1064-nm) Nd:YAG laser Arch Facial Plast Surg 2003; 5:310–15.
57 Taylor M, Prokopenko I Split-face comparison of radiofrequency versus long-pulse Nd-YAG treatment of facial laxity J Cosmet Laser Ther 2006;8:17–22.
58 Dang YY, Ren QS, Liu HX, Ma JB, Zhang JS Comparison
of histologic, biochemical, and mechanical properties of murine skin treated with the 1064-nm and 1320-nm Nd:YAG lasers Exp Dermatol 2005;14:876–82.
59 Dang Y, Ren Q, Hoecker S, et al Biophysical, histological and biochemical changes after non-ablative treatments with the 595 and 1320 nm lasers: a comparative study.
Nonablative technology for treatment of aging skin 67
Trang 7Photodermatol Photoimmunol Photomed 2005;21:
204–9.
60 Orringer JS, Voorhees JJ, Hamilton T, et al Dermal
matrix remodeling after nonablative laser therapy J Am Acad Dermatol 2005;53:775–82.
61 Doshi S, Alster T 1,450 nm long-pulsed diode laser for
nonablative skin rejuvenation Dermatol Surg 2005;31:
1223–6.
62 Alexiades-Armenakas M Rhytides, laxity, and
photoag-ing treated with a combination of radiofrequency, diode laser, and pulsed light and assessed with a comprehensive grading scale J Drugs Dermatol 2006; 5:731–8.
63 Lennox MA Febrile convulsions in childhood; a clinical
and electroencephalographic study Am J Dis Child 1949;78:868–82.
64 Ruiz-Esparza J Near painless, nonablative, immediate
skin contraction induced by low-fluence irradiation with new infrared device: a report of 25 patients Dermatol Surg 2006;32:601–10.
65 Koch D Histological changes and wound healing
response following noncontact holmium:YAG laser thermal keratoplasty Trans Am Ophthalmol Soc 1996;
94:745–802.
66 Ross E, McKinlay J, Anderson R.Why does carbon
diox-ide resurfacing work? A review Arch Dermatol 1999;
135:444–54.
67 Taub A Harnessing radiofrequency energy Skin Aging
2003;11:52–8.
68 Bassichis BA, Dayan S, Thomas JR Use of a nonablative
radiofrequency device to rejuvenate the upper one-third of the face Otolaryngol Head Neck Surg 2004;130:397–406.
69 Fitzpatrick R, Geronemus R, Goldberg D, et al.Multicenter
study of noninvasive radiofrequency for periorbital tissue tightening Lasers Surg Med 2003;33:232–42.
70 Hsu T, Kaminer M.The use of nonablative radiofrequency
technology to tighten the lower face and neck Semin Cutan Med Surg 2003;22:115–23.
71 Zelickson B, Kist D, Bernstein E, et al Histological and ultrastructural evaluation of the effects of a radiofre- quency-based nonablative dermal remodeling device: a pilot study Arch Dermatol 2004;140:204–9.
72 Kilmer S A new, nonablative radiofrequency device: liminary results In: Controversies and Conversations in Cutaneous Laser Surgery Chicago: American Medical Association Press, 2002:95–100.
pre-73 Iyer S, Suthamjariya K, Fitzpatrick R Using a quency energy device to treat the lower face: a treatment paradigm for a nonsurgical facelift Cosmet Dermatol 2003;16:37–40.
radiofre-74 Ruiz-Esparza J, Gomez J.The medical face lift: a sive, nonsurgical approach to tissue tightening in facial skin using nonablative radiofrequency Dermatol Surg 2003;29:325–32.
noninva-75 Alster T, Tanzi E Improvement of neck and cheek laxity with a nonablative radiofrequency device: a lifting experi- ence Dermatol Surg 2004;30:503–7.
76 Narins RS,Tope WD, Pope K, Ross E Overtreatment effects associated with a radiofrequency tissue-tightening device: rare, preventable, and correctable with subcision and autolo- gous fat transfer Dermatol Surg 2006;32:115–24.
77 Kist D, Burns AJ, Sanner R, Counters J, Zelickson B Ultrastructural evaluation of multiple pass low energy versus single pass high energy radio-frequency treatment Lasers Surg Med 2006;38:150–4.
78 Narins D, Narins R Non-surgical radiofrequency facelift.
J Drugs Dermatol 2003;2:495–500.
79 Ruiz-Esparza J Near painless, nonablative, immediate skin contraction induced by low-fluence irradiation with new infrared device: a report of 25 patients Dermatol Surg 2006;32:601–10.
80 Taub A, Battle E Jr, Nikolaidis G Multicenter clinical spectives on a broadband infrared light device for skin tightening, J Drugs Dermatol 2006;5:771–8.
per-68 Clinical procedures in laser skin rejuvenation
Trang 8Acne vulgaris is an exceedingly common multifactorial
disease of the pilosebaceous unit, believed to affect
approximately 40 million adolescents and 25 million
adults in the USA alone.1It is thought to be physiologic
in adolescence due to its affect on nearly 85% of young
people between the ages of 12 and 24 years.2However,
12% of adult women and 3% of adult men will have
clinical acne until the age of 44.3Many authors have
described that, in addition to long-term scarring, which
can be disfiguring, patients with acne often carry
signif-icant psychosocial morbidity, including anxiety, sleep
disturbances, clinical depression, and suicide.4–8
In many cases, acne can be successfully treated using
conventional topical or oral medications such as
antibacterials, antimicrobials, and retinoids However,
this approach often has drawbacks involving side-effect
profiles, length of treatment, and patient
compli-ance.9–13With oral retinoids, practitioners are faced
with federally mandated paperwork that takes not only
time, but also several patient visits in order to deliver
treatment.14,15
For the subset of patients who have failed these
treatment modalities, laser and light-based systems
have emerged as standalone and adjunct therapies
These devices work by targeting the components of the
pilosebaceous unit that lead to acne lesions, namely
either the resident bacterium Propionibacterium acnes,
inflammation, or the pilosebaceous unit itself
THE BUILDING BLOCKS OF ACNE
VULGARIS
In order to select the appropriate device for treating
acne, it is essential to understand the pathogenesis of
the acne lesion itself (Fig 7.1) Acne vulgaris can bebroken down into lesion types based on pathogenesisand severity: comedones, inflamed papules, nodules,and cysts The majority of data involving laser andlight-based therapies are based on the treatment of thenon-cystic form of acne vulgaris
Simply put, acne has four main pathophysiologicalfeatures: hyperkeratinization, sebum production,bacterial proliferation, and inflammation The earlycomedone is produced when there is abnormal pro-liferation and differentiation of keratinocytes in theinfundibulum, forming a keratinous plug This leads
to impaction and distention of the lower lum, creating a bottleneck affect.As the shed keratino-cytes form concretions, the sebum in the follicle thusbecomes entrapped This stage represents the nonin-flammatory closed comedone As accumulationincreases, so too does the force inside the follicleitself, eventually leading to rupture of the comedowall, with extrusion of the immunogenic contentsand subsequent inflammation Depending on thenature of the inflammatory response, pustules, nod-ules, and cysts can form
infundibu-One factor in the pathogenesis of acne vulgaris is therole of the resident P acnes found deep within the seba-ceous follicle.16–18P acnesis a slow-growing, gram-posi-tive anaerobic bacillus It contributes to the milieu ofacne production in the lipid-rich hair follicle by pro-ducing proinflammatory cytokines (e.g., interleukin-1(IL-1) and tumor necrosis factor α(TNF-α)), as well
as many lipases, neuraminidases, phosphatases, andproteases True colonization with P acnes occurs 1–3years prior to sexual maturity, when numbers canreach approximately 106/cm2, predominantly on theface and upper thorax.19Although some suggest thatthe absolute number of P acnes does not correlatewith clinical severity,16 it is common belief that the
7 Lasers, light, and acne
Kavita Mariwalla and Thomas E Rohrer
Trang 970 Clinical procedures in laser skin rejuvenation
Sebum Resident P acnes
Hair shaft
Pore
Sebaceous lobule
The pilosebaceous unit
Hair shaft
Pore
Retained keratin and lamellar concretions
Inflammation
Sebaceous lobule regression
P acnes proliferation
Inflammatory papule/pustule
Fig 7.1 The pathogenesis of acne Lasers & light based devices target either the pilosebaceous unit, to decrease sebum
production or improve sebum flow out of the gland, or the resident Propionibacterium acnes to combat acne vulgaris Comedonesresult from hyperkeravatosis at the level of the infundibulum along with increased sebum secretion.As the accumulated keratin andsebum form a plug, inflammation and proliferation of P acnes produces the clinically inflammatory acne papule
Trang 10proinflammatory mediators released by these bacteria
are at least partially responsible for the clinical acne
lesion
In practice, acne is predominantly found on the face
and to a lesser degree on the back, chest, and
shoul-ders.The majority of studies using laser and light-based
systems target acne on the face, although we present
data from a limited number of studies performed
else-where on the body
CLINICAL EXPERIENCE AND
CONSIDERATIONS
Patient screening
As new laser- and light-based systems emerge for the
treatment of acne vulgaris, the selection of patients
and the type of device to use for each one can seem
daunting In our clinical practice, we use a series of
simple guidelines before initiating laser or light-based
therapies
1 Is the patient a topical or oral medication failure?
2 Has the patient tried isotretinoin or are there
circumstances that make isotretinoin a ideal medication for the patient?
less-than-3 Is the patient’s acne mainly comedonal or are there
inflammatory acne papules as well? To what extent
is the patient’s acne nodulocystic?
4 Does the patient have acne and acne scarring?
It is important to keep in mind that most laser
systems will work to some extent Topical and oral
medications should be optimized and are generally
continued during the initial phase of treatment with
any of the devices Occasionally, laser and light-based
treatments may be used as first-line therapy, with or
without topical and oral medications, in patients
presenting with both active acne and acne scars who
also want treatment of their scars
The patient encounter
In the initial evaluation of the patient, it is important
to set realistic expectations Although many patients
see dramatic improvement with laser and light-based
therapy, some see little to no improvement Comparedwith conventional therapy, laser and light devicesrequire no daily routine, are not altered by antibioticresistance, have few systemic side-effects, and are easy
to administer, and some (infrared and radiofrequencydevices) offer significant textural improvement of acnescars On the other hand, these modalities are muchmore expensive, involve some degree of patient dis-comfort during treatment, have post-treatment recov-ery/downtime due to erythema, and require multipletrips to the dermatologist’s office As with any laserprocedure, patients’ skin phototype and underlyingpsychosocial disturbances should be considered
Choosing the appropriate laser
In most practices, the choice of device depends onwhat is available to the practitioner When multipledevices are available, it is crucial to keep in mind thearea of involvement and the presence of scarring Forexample, in large areas such as the chest and back,treatment with infrared lasers with a 4–6 mm spot size
is generally too time-consuming and painful for thepatient Instead, for wide treatment areas, light-basedtherapy with or without δ-aminolevulinic acid can be
used In cases of significant acne scarring, infraredlasers are often used, since these devices are also fre-quently employed to improve the texture of the skin,including scars The ultimate decision, however, is up
to the individual practitioner and the patient, andshould be evaluated in terms of what the treatment istargeting: the sebaceous gland or P acnes itself
TARGETING P.ACNES
P acnes produces and accumulates endogenous phyrins, namely protoporphyrin, uroporphyrin, andcoproporphyrin III,20,21as part of its normal metabolicand reproductive processes These porphyrins absorblight energy in the near-ultraviolet (UV) and blueregions of the spectrum, and can be visualized byWood’s lamp (365 nm) examination, under which theyfluoresce coral red.22
por-Porphyrins have two main absorption peaks, the Soretband (400–420 nm) and the Q-bands (500–700 nm),which make them susceptible to excitation by lasers and
Lasers, light, and acne 71
Trang 11light sources emitting wavelengths in the visible lightspectrum (400–700 nm) (Fig 7.2) Once induced,these photosensitizers generate highly reactive free-radical species, which cause bacterial destruction23,24
(Fig 7.3).The singlet oxygen formed in the reaction is
a potent oxidizer that destroys lipids in the cell wall of
P acnes Although absorption and photodynamic tion are most efficient between the wavelengths of 400and 430 nm, with enough light, the reaction may be ini-tiated with a variety of different wavelengths.Porphyrin concentration, effective fluence, wavelength
excita-of the emitted photons, and temperature at whichthe reaction is carried out all play a role in P acnesphotoinactivation.25
Photoinactivation of P acnes with visible light
UVA/UVBAfter sunlight exposure, as many as 70% of patientsreport improvement in their acne.26It is not knownwhether the UV or visible light component is primarily
72 Clinical procedures in laser skin rejuvenation
Excited porphyrin molecules
Fig 7.2 Excitation spectrum of protoporphyrins.The Soret
band represents the highest peak of light absorption and thus
sensitizer activation, while the Q-bands represent the several
weaker absorptions at longer wavelengths Because the
highest peak of absorption of porphyrins is on the blue
region (415 nm), this wavelength is used by several light
source systems for acne treatment
Fig 7.3 Mechanism of P acnes destruction by visible light interaction with porphyrins.When exposed to absorbed light lengths, porphyrins act as photosensitizers and generate highly reactive free-radical species, one of which is singlet oxygen.Theseradicals are potent oxidizers and destroy the lipids in the cell wall of P acnes
Trang 12wave-responsible for this effect In vitro experiments have
shown that P acnes can be inactivated by low-dose
near-UV radiation; however, given the potential
carcino-genicity of UVA and UVB therapy, in vivo studies have
not been able to justify this means of acne treatment,
regardless of the treatment parameters.27,28
Conclusion: While anecdotal evidence of acne
improvement over the summer has a rational basis, the
potential side-effects of prolonged UV radiation are
unacceptable risks, and other modalities should be
sought.
Blue light
The strongest porphyrin photoexcitation coefficient
(407–420 nm) lies in the Soret band It comes as no
surprise, then, that irradiation of P acnes colonies with
blue light (415 nm) leads to bacterial destruction
In vitro, colony counts of P acnes have decreased by
four orders of magnitude 120 minutes after exposure
to a metal halide lamp with a wavelength of
405–420 nm (ClearLight, Lumenis Ltd, Santa Clara,
CA) Kawada et al29used this light source on mild to
moderate acne lesions in 30 patients and found a 64%
mean acne lesion count reduction after 10 Clearlight
treatments over a 5-week period with a one- to
two-order decrease in P acnes colony count in correlated in
vitro experiments The study showed that papules and
pustules improved more than comedones, but 10% of
patients actually experienced an increase in acne
Another study utilizing the blue light source failed to
show bacterial count changes by polymerase chain
reaction (PCR) after therapy; however, damaged
P acneswere observed at the ultrastructural level.30
Shalita et al31used the ClearLight to treat 35 patients
with lesions on the face and back using 10-minute light
exposures twice weekly over a 4-week period.There was
an 80% improvement of noninflammatory and a 70%
improvement of inflammatory lesions as assessed 2 weeks
after the last treatment Using the same device, Elman
et al32carried out a split-face double-blind controlled
study (n=23) in which patients were treated a total of
eight times for 15 minutes (420 nm, 90 mW/cm2) In
this group, 87% of the treated sides showed at least a 20%
reduction of inflammatory acne lesions with a 60% mean
reduction of lesions in responders that remained steady at
2, 4, and 8 weeks post therapy In the same trial, Elman
et al32treated 10 patients with papulopustular acne in asplit-face dose-response study, exposing them tonarrowband visible blue light (90 mW/cm2) for either 8minutes or 12 minutes Although there was a more than50% decrease in inflammatory lesions in 83% of thetreatment areas, there was little difference between8- and 12-minute exposure times (a decrease of 65.9%versus 67.6%, respectively).32
Success in the treatment of acne vulgaris with theblue light may be dependent on the lesion morphol-ogy For example, Tzung et al33 showed a 60%improvement in papulopustular lesions in skin photo-types III and IV with four biweekly treatments (F-36W/Blue V, Waldmann, Villingen-Schwenningen,Germany) and worsening of nodulocystic acne in 20%
in patients using 1% clindamycin solution twice daily.The authors of this study, however, acknowledge that alimiting factor in their trial was sample size (n=13 forthe clindamycin arm and n=12 for the light therapyarm), making it difficult to draw a conclusion regard-ing diligent topical antibiotic use versus blue lighttherapy alone In fact, if all patients entered into thestudy are considered, there is no difference in theamount of clearing
Conclusion: Blue light is effective for papules and pustules more than comedones, and carries the risk of worsening nodulocystic acne It is effective in varying skin types.
Combination blue and red lightOne of the main restraints of blue light therapy foracne is that it is highly scattered in human skin and thuspenetrates poorly Red light, while less effective inphotoactivating porphyrins,35has increased depth ofpenetration into the epidermis to reach the porphyrins
in the sebaceous follicles Red light can also potentiallyinduce anti-inflammatory effects by stimulatingcytokine release from macrophages.36
Lasers, light, and acne 73