Energy-based treatment of the ageing face for skin resurfacing – Ablative and non-ablative lasers & Photodynamic therapy Flashcards
1
Q
Regarding photodamage, ablative laser skin resurfacing offers the most substantial clinical improvement.
A
T
2
Q
Regarding photodamage, non-ablative laser resurfacing is associated with several weeks of postoperative recovery.
A
F True for ablative laser skin resurfacing.
3
Q
Ablative laser skin resurfacing provides a modest improvement of photodamaged skin with a limited post-treatment recovery period.
A
F True for non-ablative laser skin resurfacing.
4
Q
Fractionated laser systems provide the benefits of higher energy treatments with fewer side effects than traditional lasers.
A
T
5
Q
Extrinsic ageing effects are usually limited to the epidermis and upper papillary dermis and are therefore amenable to treatment with laser.
A
T
6
Q
Ablative lasers are selectively absorbed by water and act to vaporise skin in a controlled manner.
A
T
7
Q
Ablative laser resurfacing carries a reduced risk of scarring and pigmentary alteration compared to non-ablative methods.
A
F Increased risk.
8
Q
Ablative laser resurfacing can be safely carried out in patients with darker skin types.
A
F Ideally skin type I or II.
9
Q
Preoperative use of topical tretinoin, hydroquinone or glycolic acid for several weeks reduces the incidence of postablative laser hyperpigmentation.
A
F
10
Q
Prophylactic antibiotics should be used postablative laser to reduce the possibility of bacterial contamination and overgrowth in the de-epithelialised skin.
A
F Controversial. Studies haven’t shown any significant change in infection rate.
11
Q
Pts with a history of herpes labialis should receive prophylactic oral antivirals starting 1 day prior to resurfacing and continuing for 10 days postoperatively.
A
T
12
Q
Ablative resurfacing lasers include: pulsed CO2 (10600nm), pulsed erbium:YAG (2940), and fractionated (10600 and 2940nm)
A
T
13
Q
Using CO2 laser, water-containing tissue is vaporised to a depth of approximately 20-100um, producing a zone of thermal damage ranging from 20 to 150um.
A
F Vaporisation depth 20-60um.
14
Q
Using CO2 laser, depth of ablation is directly correlated with number of passes performed and is usually restricted to the epidermis and upper papillary dermis.
A
T
15
Q
Using CO2 laser, stacking of laser pulses doesn’t cause excessive thermal injury.
A
F Does. Risk of scarring.
16
Q
Using CO2 laser, an ablative plateau is reached, with less effective tissue ablation and accumulation of thermal injury.
A
T This effect is due to reduced water content after initial dessication.
17
Q
With any laser system, complete removal of partially dessicated tissue and avoidance of pulse stacking is paramount to prevention of excessive thermal accumulation.
A
T
18
Q
The objective of ablative laser skin resurfacing is to vaporise tissue to the reticular dermis.
A
F Papillary dermis.
19
Q
Limiting the depth of ablative laser penetration to the reticular dermis decreases the risk for scarring and permanent pigmentary alteration.
A
F Papillary dermis.
20
Q
For CO2 laser, whether or not previous treatments have been delivered to an area is irrelevant when choosing treatment parameters.
A
F
21
Q
Areas with thinner skin require fewer passes with a CO2 laser.
A
T
22
Q
CO2 laser resurfacing of non-facial areas (eg neck, chest) should be avoided due to the relative paucity of pilosebaceous units in these areas.
A
T
23
Q
CO2 laser resurfacing can offer at least a 50% improvement over baseline in overall skin tone and wrinkle severity.
A
T
24
Q
The most profound effects of CO2 laser resurfacing occur in the epidermis.
A
F Papillary dermis – elastotic material replaced with normal collagen bundles.
25
The advantages of CO2 laser skin resurfacing are the excellent tissue contraction, haemostasis, prolonged neocollagenesis and collagen remodelling.
T
26
Absolute CI to CO2 laser resurfacing includes active infection or an inflammatory skin condition involving the areas to be treated.
T
27
Contraindication to CO2 laser resurfacing includes the use of isotretinoin within the preceding 2 years.
F Preceding 6-12 months.
28
Contraindication to CO2 laser resurfacing includes a history of keloids.
T
29
YAG laser emits a 2940nm wavelength light corresponds to the 3000nm absorption peak of water-
T
30
The absorption coefficient of the Er:YAG laser makes it less efficiently absorbed by water-containing tissue compared with the CO2 laser.
F 12-18 times more efficiently absorbed.
31
The pulse duration for Er:YAG is much shorter than the CO2 laser, resulting in decreased thermal diffusion, less effective haemostasis and increased intraoperative bleeding which hampens deeper dermal treatment.
T
32
The amount of collagen contraction is increased with Er:YAG compared to CO2 laser.
F Decreased due to limited skin injury.
33
Much narrower zones of thermal necrosis are produced with Er:YAG compared to CO2 laser.
T
34
There is no distinctive popping sound with Er:YAG laser use compared to CO2 laser.
F Popping sound produced by ejection of dessicated tissue.
35
With Er:YAG laser, because little tissue necrosis is produced with each pass of the laser, manual removal of dessicated tissue is often unnecessary.
T
36
short-pulsed erbium laser fluences used most often range from 30-50um J/cm2, depending on the degree of photodamage and anatomic location.
F 5 to 15 J/cm2.
37
When lower fluences are used, it is often necessary to perform multiple passes to ablate the entire dermis with Er:YAG laser.
T
38
The depth of ablation with the short-pulsed Er:YAG doesn’t diminish with successive passes.
T Because the amount of thermal necrosis is minimal with each pass.
39
It takes 3-4 times as many passes with the CO2 laser to achieve similar depths of penetration as with one pass of the Er:YAG laser at typical treatment parameters.
F Other way around.
40
Because more pulses must be used with the Er:YAG laser, there is an increased possibility of uneven tissue penetration.
T
41
Areas treated with Er:YAG immediately whiten after treatment and then the white colour quickly fades.
T
42
Short-pulsed Er:YAG can be used for superficial or dermal lesions
T
43
Short-pulsed Er:YAG tends to have a longer recovery period.
F Shorter.
44
Re-epithelialisation post Er:YAG laser is completed within 8.5 days on average, compared with 5.5 days for multiple-pass CO2 laser procedures.
F Other way around.
45
Post-operative pain and duration of erythema are reduced after short-pulsed Er:YAG compared to CO2 laser.
T
46
Post-op erythema from Er:YAG resolves within 1-2 weeks.
F 3-4 weeks.
47
Er:YAG is contraindicated in darker skin phototypes.
F
48
The major disadvantage of short-pulsed Er:YAG is its limited ability to effect significant collagen shrinkage.
T
49
The final result with Er:YAG ablation is typically less impressive compared with CO2 resurfacing for deeper rhytides.
T
50
For mild photodamage, Er:YAG only typically produces improvement of about 20%.
F 50%.
51
Ablative fractional resurfacing devices have the ability to achieve comparable clinical results to non-fractional methods.
T
52
Ablative fractional resurfacing devices can keep the majority of the dermis intact, thus allowing quicker recovery periods and an improved safety profile.
F Epidermis.
53
Fractional lasers deliver energy through macroscopic zones of thermal injury, leading to coagulation necrosis and resultant new collagen formation.
F Microscopic.
54
Annular coagulation of dermal collagen occurs with fractional ablative laser, with increasing fluences resulting in increasing treatment depths.
T
55
With fractional ablative laser, the deep dermal ablated zones are surrounded by zones of sparing, which result in quicker recovery compared to non-fractional methods.
T
56
Using fractional ablative laser, multiple treatments are required for any noticeable clinical improvement.
F Improvement in texture, dyschromia and mild laxity after one treatment.
57
Fraxel is a fractionated CO2 laser.
T
58
With fractional laser, ablation depth and the residual thermal damage depend on energy density and the number of stacked pulses used.
T
59
Fractional and non-fractional laser treatments should never be combined.
F
60
Fractional laser ablation requires longer recovery time than other ablative lasers.
F Average 5-7 days.
61
Temporary bronzing, acneiform eruptions and milia formation can occur after fractional laser ablation.
T
62
Results from a single fractional laser ablative treatment are noted 3-6 weeks after the procedure.
F 3-6 months, after collagen remodelling complete.
63
Ablative fractional laser resurfacing cannot be performed on the neck and chest.
F
64
Scarring and pigmentary alteration are potential side effects of ablative fractional laser.
F These have never been reported.
65
Expected side effects of ablative laser resurfacing include erythema, oedema and pruritus.
T
66
Mild complications of ablative laser include extended erythema, milia, acne and contact dermatitis.
T
67
Severe complications of ablative laser include hypopigmentation, hypertrophic scarring and ectropion.
T
68
Erythema after ablative laser is always mild and resolves quickly.
F Can be intense and may persist for months.
69
Degree of erythema is unrelated to the depth of ablation and the number of laser passes performed.
F Correlates directly with this.
70
Underlying rosacea or dermatitis can aggravate the erythema seen post-laser ablation.
T
71
Post-operative erythema resolves spontaneously
T May be reduced with the application of topical ascorbic acid
72
Topical ascorbic acid should be avoided post-laser ablation.
F Can reduce postoperative erythema.
73
Topical ascorbic acid can be used immediately after laser ablation.
F Should wait at least 4 weeks.
74
Topical agents such as retinoids, glycolic acid and fragrance-containing or chemical-containing cosmetics and sunscreens should be strictly avoided in the early postoperative period after ablative laser.
T
75
Minor side effects of laser resurfacing include milia formation and acne exacerbation.
T
76
Milia and acne seen post ablative laser are thought to be due to occlusive dressing and ointments in the postoperative periods, particularly in patients who are prone to acne.
T
77
Reactivation of labial HSV post laser ablation is most likely due to thermal tissue damage and epidermal disruption.
T
78
After CO2 resurfacing, approximately 20% of patients develop a localised or disseminated form of HSV.
F 7-10%, even with appropriate prophylaxis
79
Infections of HSV occurring as a complication of laser resurfacing tend to develop within the first postoperative week.
T
80
For HSV prophylaxis in the setting of ablative laser, patients should begin prophylaxis 1 week prior to surgery and continue for 1 week postoperatively.
F Begin by day of surgery, continue 7-10 days postop.
81
Ectropion of the lower eyelid is more likely to occur post ablative laser in patients who have had previous blepharoplasty or other surgery of the periorbital area.
T
82
The snap test should be performed on the lower eyelid prior to ablative laser – laser resurfacing should be avoided if the skin does not return briskly to its normal resting position.
T
83
There is no indication for altering fluence of laser passes when treating the periorbital area.
F Use lower fluence and fewer passes to reduce risk of lid eversion.
84
Postoperative hypopigmentation is often not seen for several months after ablative laser.
T
85
There is a lower risk of infection associated with the use of ‘closed’ dressing techniques post ablative laser.
F Higher risk reported.
86
Pale skin tones have a lower incidence of undesirable postoperative hyperpigmentation after ablative laser.
T
87
There are no risks associated with ablative skin resurfacing in scleroderma, LE or vitiligo.
F These conditions can worsen.
88
Koebnerisation of psoriasis, verrucae and molluscum can occur after ablative skin resurfacing.
T
89
Concomitant isotretinoin use could potentially lead to increased risk of postoperative hypertrophic scar formation.
T Due to effects on wound healing and collagenesis.
90
Treatment with laser skin resurfacing should be delayed for at least 1-2 years after cessation of isotretinoin.
F 6-12 months
91
There is a greater risk of scar formation after laser resurfacing, independent of the laser’s selectivity and the operator’s expertise.
T
92
Complete control of acne should be obtained prior to ablative laser skin resurfacing.
T
93
patients with mild to moderate facial photodamage with realistic treatment expectations are the best candidates for non-ablative procedures.
T
94
There is no need to avoid sun exposure prior to non-ablative laser procedures.
F Should be avoided, esp with PDL or IPL (shorter wavelength systems).
95
Non-ablative laser systems stimulate collagen production and dermal remodelling without wounding the epidermis.
T
96
Non-ablative lasers include mid-infrared lasers, visible light lasers and IPL systems.
T
97
Devices which emit light within the infrared portion of the electromagnetic spectrum (1000-1500nm) are weakly absorbed by superficial water-containing tissue, thereby they don’t penetrate deep tissue.
F Deeper tissue penetration is affected.
98
Contact cooling hand pieces or dynamic cryogen devices are used for all ablative laser systems.
F Non-ablative laser systems.
99
Treatment of facial photodamage with non-ablative technology does not produce results comparable to those of ablative carbon lasers.
T
100
The long pulsed Nd:YAG 1320nm wavelength laser is associated with a high scattering coefficient that allows for dispersion of laser irradiation throughout the dermis.
T
101
The long pulsed Nd:YAG 1320nm wavelength hand piece contains two portals: the laser beam itself, and a dynamic cryogen spray apparatus used for epidermal cooling.
F 3rd portal – thermal feedback sensor.
102
Using the Nd:YAG laser, epidermal temperatures must be kept lower than 50deg C in order to prevent unwanted sequelae from excessive heat production.
T
103
Only one treatment session with the Nd:YAG laser is usually needed for maximum mitigation of fine rhytides.
F Usually three or more typically once a month.
104
Side effects of Nd:YAG long pulsed laser are generally mild and include transient oedema and erythema.
T
105
The long-pulsed Diode laser has a wavelength of 1540nm.
F 1450nm.
106
The diode laser targets dermal water and penetrates skin to an approximate depth of 100nm.
F 500nm.
107
For non-ablative lasers, the perioribtal area is usually more responsive to laser treatments than the perioral area.
T
108
The Erbium:glass laser has a wavelength of 1450nm.
F 1540nm.
109
The erbium:glass laser has the least amount of melanin absorbed compared with the long-pulsed Nd:YAG and diode laser systems.
T
110
Pulsed-dye lasers used for ablation have a wavelength of 585nm and 595nm.
T
111
The most common side effects of PDL treatment include mild oedema, purpura, and permanent post-inflammatory hyperpigmentation.
F Transient post-inflammatory hyperpigmentation.
112
IPL emits a broad continuous spectrum of light in the range of 515-1200nm.
T
113
For IPL, cut-off filters are used to eliminate shorter wavelengths depending on the clinical application, with shorter filters favouring heating of melanin and haemoglobin.
T
114
IPL can improve wrinkling, skin coarseness, irregular pigmentation, pore size and telangiectasia.
T
115
Ablative fractional lasers produce microscopic treatment zones (MTZs).
F Non-ablative.
116
In MTZs , the epidermis is left intact, allowing for rapid repopulation of the ablated columns of tissue.
T
117
Re-epithelisiation after fractional laser treatment is completed within 2 days following treatment.
F 1 day.
118
Healing post fractional laser takes place through extrusion of microepidermal necrotic debris (MEND), which represents damaged epidermal components.
T
119
MEND is clinically manifest as superficial exfoliation.
T
120
During the reparative phase after non-ablative fractional laser, the skin appears erythematous.
F Bronze.
121
Treatment of complete cosmetic units, or the whole face, is generally recommended with non-ablative fractional laser.
T
122
MTZs are completely replaced by new collagen over the course of 6 months.
F 3 months.
123
The two treatment parameters in non-ablative fractional laser are the treatment energy and the treatment density (ie. the total number of MTZs per square cm.
T
124
For scarring purposes, higher treatment energies are used with lower treatment densities for non-ablative fractional lasers.
T
125
For textural improvement with non-ablative fractional lasers, a medium energy is utilised.
T
126
With non-ablative fractional lasers, pigmentary disturbances are best treated with lower treatment energies which allow for deeper penetration.
F More superficial penetration.
127
Darker skin phototypes should not be treated with non-ablative fractional lasers.
F Treat safely by reducing total treatment density while maintaining energy setting.
128
Melasma can paradoxically darken following fractional photothermolysis.
T
129
For topical anaesthesia, preparations containing tetracaine should be avoided in patients with a known allergy to sulfa-containing medications.
T
130
The expected side effects of fractional non-ablative laser (erythema, oedema, xerosis) usually resolve within 2 weeks.
F 4 days.
131
Reactivation of herpes labialis tends not to occur with non-ablative laser skin remodelling.
F Can occur due to intense heat produced by laser.
132
Non-ablative dermal remodelling treatments are typically delivered at monthly intervals, with final clinical results taking several months after laser irradiation to be realised.
T
133
The topical photosensitiser aminolevulinic acid (ALA) is a 20% concentration solution.
T
134
The topical photosensitiser methyl aminolevulinate cream (MAL) is commercially available as a 100mg/g cream.
F 160mg/g cream.
135
Both ALA and MAL are strongly absorbed into sun-damaged cells and NMSCs, but not the pilosebaceous unit.
F Are absorbed into pilosebaceous unit.
136
ALA and MAL are transformed via the heme pathway into their active form, protoporphyrin IX (PpIX).
T
137
ALA should be used with a blue light source of 630nm peak output for PDT.
F 417nm peak output.
138
MAL cream under occlusion for 3 hours followed by illumination with a red light source for PDT.
T 630nm peak output.
139
After PDT, post-treatment crusting and erythema typically resolve within 2 days.
F Persist up to 10 days.
140
PDT can improve fine lines, skin texture, erythema and pigmentation.
T
141
Patients must adhere to strict sun and bright light avoidance for 48 hours after PDT.
T
142
There are no contraindications for PDT – it is a safe treatment method for NMSCs, AKs and photodamage.
F CIs incl porphyrin disorder, photosensitivity disorder or photosensitising meds.
143
Topical anaesthesia is required prior to application of the light source in PDT.
T
144
Forced air cooling devices can be used to alleviate any discomfort associated with PDT.
T
145
During the illumination, short breaks with cold water mists should not be used to help patients better tolerate the procedure.
F Can be used.
146
MAL cream should be removed prior to light activation during PDT.
T
147
Eye protection does not need to be worn during PDT.
F
148
For photodamage, PDT can be repeated monthly until desired cosmetic results are achieved.
T
149
Any remaining lesion after PDT for AKs/photodamage should be treated with further cycles.
F These should be biopsied.
150
After light activation during PDT, the skin should not be cleansed.
F Should cleanse thoroughly w mild soap/water.
151
Further activation of PpIX can occur for up to 48 hours after PDT.
T
152
Phototoxicity after PDT should to be treated urgently with systemic corticosteroids, emollient and ice to avoid scarring or dyspigmentation.
T
