Laser Treatment Flashcards
(99 cards)
1
Q
A 42-year-old woman is scheduled to undergo facial resurfacing with a fractionated carbon dioxide laser. This procedure acts by targeting which of the following substances in skin? A) Collagen B) Elastin C) Hyaluronic acid D) Melanin E) Water
A
E) Water
2
Q
Water and skin resurfacing
A
The principle of selective photothermolysis as applied to skin resurfacing (ablation) is based upon water content. The epidermis is composed of 90% water and is vaporized at temperatures in excess of 212°F (100°C). The carbon dioxide laser has water as its chromophore. The carbon dioxide laser has a wavelength of 10,600 nm and has a water absorption coefficient of 800/cm.
3
Q
A 45-year-old woman comes to the office because of a rash and a burning sensation on her face 1 week after undergoing carbon dioxide cutaneous laser resurfacing. Physical examination shows erythematous pustules on the right side of the face in the V3 distribution. Which of the following agents is the most appropriate treatment? A ) Oral acyclovir B ) Oral cephalexin C ) Oral prednisone D ) Topical bacitracin E ) Topical petrolatum
A
A ) Oral acyclovir
4
Q
Most common infectious complication associated with skin resurfacing
A
The most frequent infectious complication associated with resurfacing is a reactivation of the herpes simplex virus (HSV). It is suspected that direct laser trauma to the skin leads to latent viral activation and shedding.
5
Q
Percent of patients undergoing laser resurfacing with HSV outbreak and prophylaxis indications
A
Herpetic outbreaks are experienced by roughly 2 to 7% of all laser-treated patients despite antiviral prophylaxis. In addition, due to the high incidence of latent HSV infection, any patient (regardless of prior HSV history) planning to undergo full-face or perioral resurfacing should be given oral antiviral prophylaxis in an effort to reduce viral reactivation, which could subsequently lead to scarring.
6
Q
Early detection of post laser HSV
A
Early postlaser detection of HSV is often difficult because there is no intact epithelium, and, rather than the characteristic grouped vesicles or pustules, infection is manifested by small, superficial erosions. Symptoms of HSV reactivation include tingling, burning, or discharge from isolated foci within the treated areas.
7
Q
Extensive postlaser eruptions of HSV: complications
A
Extensive eruptions can result in disseminated infection and atrophic scarring, and therefore, must be recognized early and treated aggressively
8
Q
Treatment of peri-laser resurfacing HSV outbreak
A
Oral antiviral agents, such as acyclovir, famciclovir, or valacyclovir, are routinely administered 1 to 2 days before the laser resurfacing procedure and are continued for another 7 to 10 days until reepithelialization is complete. If a herpetic outbreak occurs despite prophylaxis, patients should either be switched to a different antiviral agent or have their dosage increased to maximal herpes zoster doses (acyclovir 800 mg 5 times daily or famciclovir or valacyclovir 500 mg 3 times daily).
9
Q
A 45-year-old woman is being evaluated because of discrete, red, facial capillaries that she would like to have removed. Which of the following lasers is most appropriate to ablate the vessels? A ) KTP (532-595 nm) B ) Q-switched ruby (694 nm) C ) Nd:YAG (1064 nm) D ) Er:YAG (2940 nm) E ) Carbon dioxide (10,600 nm)
A
A ) KTP (532-595 nm)
The 532-595 nm wavelength is the most appropriate choice, as it has the highest affinity for the vessels and can be more effective with the appropriate settings.
10
Q
1064-nm laser application
A
The 1064-nm laser can be used for hair reduction or collagen stimulation but works on the deeper layers and is more specific for darker pigmentation of vessels, such as blue. It can be used for vessel reduction in the leg; however, facial vessels are more superficial and often more red than blue in coloration.
11
Q
A 50-year-old woman comes to the office because she developed a vesicular rash five days after undergoing full face carbon dioxide laser resurfacing to treat sun-damaged skin and acne scars. Which of the following is the most appropriate initial step in management?
A ) Administration of an antibiotic
B ) Administration of an antimicrobial scrub
C ) Administration of an antiviral agent
D ) Administration of a corticosteroid
E ) Observation
A
C ) Administration of an antiviral agent
12
Q
HSV incubation period from time of skin resurfacing procedure
A
HSV infection has a three-to five-day incubation period from the time of the procedure to the onset of clinical infection.
13
Q
A 59-year-old woman comes to the office because she is unhappy with the long-term results of carbon dioxide laser resurfacing performed three years earlier to treat rhytides on the upperlip. Which of the following is the most likely complication that is causing her dissatisfaction? A ) Hyperpigmentation B ) Hypertrophic scarring C ) Hypopigmentation D ) Persistent erythema E ) Telangiectasia
A
C ) Hypopigmentation
14
Q
The success of carbon dioxide laser skin resurfacing is generally attributed to:
A
The success of carbon dioxide laser skin resurfacing is generally attributed to long-termne collagenesis and neoelastogenesis
15
Q
Main drawback of carbon dioxide laser resurfacing; other potential complications
A
The main drawback is a high rate of hypopigmentation, which is very distressing to patients.
Although persistent erythema and hyperpigmentation can be troublesome in the first year after treatment, neither is typically seen as long-term sequelae of the procedure. Hypertrophic scarring is a possible complication of treatment; however, it is not reported as a common long-term complication of the procedure in several large series of studies.
16
Q
Effectiveness of carbon dioxide laser resurfacing on the upper lip
A
Carbon dioxide laser resurfacing is a highly effective treatment of rhytides of the upper lip that will last for a long time (more than six years) with low rates of recurrence.
17
Q
(Red, purple, green, yellow, blue, black…CF)
A 35-year-old woman comes to the office for removal of the tattoo shown in the photograph. The tattoo was professionally applied. The patient undergoes five treatments with a Q-switched Nd:YAG (1064 nm) laser. After completion of laser therapy, areas of red pigment remain. Additional treatment with which of the following lasers is the most appropriate next step in management?
(A)Erbium: YAG (2940 nm)
(B)Q-switched alexandrite (755 nm)
(C)Q-switched Nd:YAG (532 nm)
(D)Q-switched ruby (694 nm)
(E)Ultrapulsed CO2 (10,600 nm
A
C)Q-switched Nd:YAG (532 nm)
18
Q
Estimated percent of people who have considered tattoo removal
A
An estimated seven to 20 million people in the United States have at least one tattoo, and approximately 17% have considered tattoo removal.
19
Q
Professional vs amateur tattoos
A
Compared with amateur tattoos, professional tattoos often contain various densely packed colored pigments at a uniform depth
20
Q
Type of laser for tattoo removal
A
Quality-switched (Q-switched) lasers enable the deposit of energy very quickly, thus rupturing cells containing pigment and triggering phagocytosis and packaging of tattoo fragments for lymphatic drainage. Because different pigments respond to different wavelengths, it is rare that one laser system can be used alone to remove all combinations of inks.
21
Q
Q-switched Nd:YAG 1064 nm and tattoos
A
The Q-switched Nd:YAG 1064 nm has the deepest penetration and carries the least risk of hypopigmentation but is least effective in removing brightly colored tattoos.
22
Q
Q-switched Nd:YAG 532 nm and tattoos
A
The Nd:YAG 532 nm is effective for red, orange, and occasionally yellow ink. Because this wavelength is also absorbed by hemoglobin, purpura often occurs after treatment and can last for seven to 10 days
23
Q
Q-switched alexandrite and ruby lasers vs tattoos
A
The Q-switched alexandrite and ruby lasers are effective for the treatment of black, blue, and green pigment; however, because their wavelengths are well absorbed by melanin, transient hypopigmentation and even permanent depigmentation can be a problem, particularly in patients with Fitzpatrick type V or VI skin types
24
Q
An Er:YAG laser targets which of the following chromophores? (A)Blue dye (B)Collagen (C)Hemoglobin (D)Melanin (E)Water
A
(E)Water
25
Amount of heat generated by a laser is a function of:
Lasers generate heat in the target tissue that dissipates by conduction. The amount of heat generated is a function of the wavelength of the laserand the duration of exposure.
26
Selective tissue injury of a laser is caused by:
Selective tissue injury is caused by the choice of a wavelength of energy that is specific for a particular target chromophore within the skin.
27
Er:YAG laser
The Er:YAG laser is an ablative laser with a wavelength of 2940 nm and a targetchromophore of water. There is less thermal diffusion to the surrounding tissues with an Er:YAG laser than with a CO2 laser, although both have the same target chromophore
28
Nd:YAG laser
The Nd:YAG laser affects blood vessels, red blood cells, collagen, and melanin.
29
Fractional photothermolysis
Fractional photothermolysis uses a blue dye template, which also serves as the target chromophore, and divides the skin into microscopic thermal zones.
30
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A 42-year-old woman comes to the office for consultation regarding improvement of the appearance of her facial skin. Resurfacing with a carbon dioxide laser is contraindicated in this patient if she has been treated recently with which of the following drugs?
(A)Acyclovir
(B)Glycolic acid
(C)Hydroquinone
(D)Isotretinoin
(E)Tretinoin
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(D)Isotretinoin
31
Isotretinoin and skin resurfacing procedures
Isotretinoin (Accutane) is contraindicated in any skin resurfacing procedures. Although its use for the treatment of acne is regulated, because of its significant risk for causing birth defects, it may also interfere with healing after resurfacing procedures. This complication may occur even if themedication has not been used for one year.
32
Duration between isotretinoin treatment and skin resurfacing procedure
Isotretinoin use should be discontinued for at least one year - 18 months before skin resurfacing procedures
33
A 37-year-old woman who underwent full-face resurfacing with a carbon dioxide laser seven days ago comes to the office because she has chills, malaise, and painful lesions of the face. Temperature is 38.7EC (101.7EF). Physical examination shows ulcerated, diffusely distributed lesions over the face. A four-day regimen of acyclovir 400 mg three times daily has not alleviated the patient’s symptoms. Results of Tzanck smear and viral culture are pending. Which of the following therapies is the most appropriate next step in management?
(A)Intravenous acyclovir and ciprofloxacin
(B)Oral acyclovir at a higher dose
(C)Oral acyclovir at a more frequent dose
(D)Oral valacyclovir
(E)Oral valacyclovir and ciprofloxacin
(A)Intravenous acyclovir and ciprofloxacin
Herpes simplex is difficult to recognize on resurfaced skin. Moreover, primary or secondary bacterial infection cannot be overlooked. Therefore, antibiotic coverage is prudent, particularly until culture results are available.
This patient presented with signs and symptoms of systemic herpetic infection, which may include disseminated cutaneous lesions, shortness of breath, high fever and chills, malaise, headache, and neurologic changes. When these are present, hospital-based treatment with intravenous antiviral and antibiotic therapy is warranted.
34
Workup when a patient experiences an outbreak of herpes simplex despite use of antiviral prophylaxis
When a patient experiences an outbreak of herpes simplex despite the use of antiviral prophylaxis, the physician should perform a Tzanck smear and send viral, fungal, and bacterial cultures. The anti-herpetic dosage should be increased to zoster levels as well (acyclovir 800 mg five times a day, valacyclovir 500 mg three times a day.
35
Signs and symptoms of systemic herpetic infection
Signs and symptoms of systemic herpetic infection may include disseminated cutaneous lesions, shortness of breath, high fever and chills, malaise, headache, and neurologic changes. When these are present, hospital-based treatment with intravenous antiviral and antibiotic therapy is warranted.
36
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A 28-year-old womanundergoes laser removal of a multicolored tattoo on the upper arm. The tattoo was professionally applied. Which of the following laser wavelengths is most appropriate to remove the yellow portions of this tattoo?
(A) 532 nm
(B) 698 nm
(C) 755 nm
(D) 1064nm
(E) 1320 nm
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(A) 532 nm
37
Orange and yellow tattoo inks are targeted by _____ range lasers
Orange and yellow tattoo inks are targeted specifically by lasers in the low (500-nm) range, making the 532-nm Q-switched Nd:YAG laser or the 510-nm pulsed-dye laser optimal for treatment.
38
First laser system developed solely for non ablative skin remodeling
Nd:YAG, long-pulsed 1320-nm laser treatment was the first system developed solely for nonablative skin remodeling.
39
Black tattoo inks may be targeted by _____ range lasers
The Q-switched Nd:YAG (1064-nm) laser is optimal for black pigment.
40
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A 40-year-old woman with Fitzpatrick type II skin is scheduled to undergo carbon dioxide laser resurfacing for facial rhytides. Current use of which of the following medications is a contraindication for use of carbon dioxide laser resurfacing in this patient?
(A) Hydroquinone
(B) Isotretinoin
(C) Nicotine patch
(D) Oral contraceptive
(E) Valacyclovir
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(B) Isotretinoin
41
Isotretinoin suppresses re-epithelialization via:
| This is important because:
Isotretinoin suppresses skin appendageal activity and, therefore, prevents normal reepithelialization after resurfacing.
If the wounded skin is not reepithelialized within 10 days, scarring may result.
42
Hydroquinone
Hydroquinone is a tyrosinase inhibitor and results in lightening (bleaching) of the skin. It is frequently used before and after skin resurfacing to prevent hyperpigmentation
43
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Which of the following treatment systems activates thetopical formulation of 5-aminolevulinic acid?
(A) Erbium laser
(B) Phenol
(C) Pulsed-dye laser
(D) Radiofrequency
(E) Tretinoin
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(C) Pulsed-dye laser
44
5-Aminolevulinic acid
5-Aminolevulinic acid (ALA) is a topical medication that, when placed on the skin, penetrates the altered epithelial epidermis and is absorbed into the keratinocytes, whereby it is converted enzymatically into protoporphyrin IX. The application of light results in the release of cytotoxic radicals, which render this drug useful for the treatment of cutaneous lesions.
Protoporphyrin IX has a maximum absorption at 410, 630, and 690 nm. Because of this, blue light systems (400B450 nm), pulsed-dye systems (585B595 nm), and photo rejuvenation systems (560B1200 nm) all may activate the drug.
45
Systems that activate 5-Aminolevulinic acid
Blue light systems (400B450 nm), pulsed-dye systems (585B595 nm), and photo rejuvenation systems (560B1200 nm) all may activate the drug.
46
Use for 5-Aminolevulinic acid
5-Aminolevulinic acid has been used for the treatment of acne vulgaris as well as aging.
47
Complications of use of 5-Aminolevulinic acid
5-Aminolevulinic acid requires up to one hour of application time before initiation of therapy and may result in several days of swelling, erythema, and exfoliation. Patients also tend to be photosensitive for up to 48 hours after treatment.
48
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A 32-year-old woman comes to the office for consultation regardingremoval of a black and red tattoo from the left breast. The most effective intervention for removal of this patient’s tattoo is treatment with which of the following types of lasers?
(A) Carbon dioxide
(B) Pulsed-dye
(C) Q-switched alexandrite
(D) Q-switched Nd:YAG
(E) Q-switched ruby
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(D) Q-switched Nd:YAG
49
A Q-switched laser reduces damage to surrounding normal skin via
A Q-switched laser delivers short pulses, which reduces damage to surrounding normal skin.
50
Mechanism of action of a frequency-doubled Q-switched Nd:YAG laser
A frequency-doubled Q-switched Nd:YAG laser has a crystal that doubles the frequency of the Nd:YAG laser from 1064 nm to 532 nm. In the 532-nm (green) wavelength, the laser removes red pigments effectively. When switched to the full 1064-nm (red) wavelength, it effectively removes black pigments. The mechanism of action is believed to be selective fragmentation of the targeted pigment followed by phagocytosis and lymphatic clearing
51
Why does a carbon dioxide laser pose a high risk in tattoo removal?
A carbon dioxide laser removes tattoos by targeting water in the skin. Therefore, it nonselectively destroys tissue, including pigment-bearing cells. Because it poses a high risk of hypopigmentation and hypertrophic scarring, it is not the laser of choice for removing professional tattoos
52
An 18-year-old woman has a large arteriovenous malformation on the face that has ulcerated and bled vigorously several times. Which of the following is the most appropriate treatment option?
(A) Intralesional administration of interferon
(B) Distal embolization under superselective angiographic control
(C) Ligation of the feeding vessels
(D) Intralesional excision to minimize tissue loss
(E) Aggressive resection with immediate flap reconstruction
(E) Aggressive resection with immediate flap reconstruction
Distal embolization of the lesion can be performed under angiographic control before excision to limit blood loss but is not an effective treatment in itself.
Intralesional excision is associated with a high risk for recurrence.
Intralesional interferon has not been shown to provide benefit in the treatment of arteriovenous malformations.
53
Management of large AVM of the face with ulceration and bleeding
Large arteriovenous malformation (AVM) on the face characterized by ulceration and bleeding:
The most appropriate management is aggressive resection to eliminate the lesion immediately. In addition, because aggressive resection of an AVM typically exposes vital structures and leaves a cosmetically disfiguring defect, immediate reconstruction with a flap is indicated. Arteriography, Doppler ultrasonography, and/or MRI should be obtained preoperatively to delineate the extent of the lesion.
Distal embolization of the lesion can be performed under angiographic control before excision to limit blood loss.
54
Result after ligation of feeding vessels of AVM
Ligation of the feeding vessels without subsequent resection will further worsen the AVM because it will result in the development of new collateral vessels.
55
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Which of the following laser wavelengths is ideal for treating the lesion shown above? (Port wine stain)
(A) 532 nm
(B) 585 nm
(C) 788 nm
(D) 810 nm
(E) 2940 nm
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(B) 585 nm
56
Demographics of port wine stain
These lesions may occur anywhere on the body but are most commonly seen on the face. They occur unilaterally in 85% of patients and involve more than one dermatome in almost 70% of patients. These lesions are more commonly seen in women than in men (3:1) and may be hereditary (25%).
57
Port wine stain progression
The natural progression of these lesions with age includes darkening of the lesion due to the presence of deoxyhemoglobin, with thickening of the dermis and a cobblestoning appearance. It should be noted that as the lesions get darker, they are more difficult to treat.
58
Port wine stain treatment
Because of its depth, penetration, and specificity for vascular targets, the 585-nm laser is the best treatment choice for these lesions. Treatment with the pulsed-dye laser typically results in less epidermal injury and risks for scarring. It should be used with caution in patients with pigment.
59
532-nm laser (KTP)
The 532-nm laser (KTP) is useful for superficial vascular telangiectasis.
60
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Which of the following light sources is non coherent?
(A) Alexandrite
(B) Diode
(C) Intense pulsed
(D) Pulsed-dye
(E) YAG
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(C) Intense pulsed
61
Intense pulsed light overview
Intense pulsed (broadband) light is a high-intensity light source that emits polychromatic energy. It supplies noncoherent light over a broad spectrum of wavelengths from 510 to 1200 nm. This broad spectrum allows variability regarding target selection and skin types.
62
Intense pulsed light uses
Intense pulsed-light systems are commonly used to treat hyperpigmentation, telangiectasis, rosacea, excessive or unwanted hair, rhytids, and vascular malformations. When used for photoaging, they have been shown to produce long-term positive results on the face, neck, and chest. They have also demonstrated improvement in telangiectasis and pigmentation
63
Intense pulsed light side effects
Adverse effects of intense pulsed light include crusting, erythema, and purpura
64
A 23-year-old woman has carbonaceous material embedded in the skin after sustaining injuries in a combustion accident at work. A photograph is shown above. Which of the following is the most appropriate management?
(A) Carbon dioxide laser therapy
(B) Nd:YAG laser therapy
(C) Deep dermabrasion
(D) Wide local excision and coverage with a thin split-thickness skin graft
(B) Nd:YAG laser therapy
In the past, traumatic tattoos were removed with mechanical abrasive techniques, including dermabrasion, salabrasion, and the rubbing of table salt into the skin, each of which produced satisfactory results in superficial tattoos. However, better results have recently been demonstrated with laser therapy, which involves the removal of successive layers of skin to expose the intradermal pigment, which is subsequently vaporized
65
Treatment of choice for patients with certain types of foreign material embedded in the skin
In patients who have certain types of foreign material embedded in the skin, especially road asphalt, carbonaceous material, or ink from amateur tattoos, the most appropriate method of removal is multiple treatments with the Nd:YAGlaser.
In the past, traumatic tattoos were removed with mechanical abrasive techniques, including dermabrasion, salabrasion, and the rubbing of table salt into the skin, each of which produced satisfactory results in superficial tattoos. However, better results have recently been demonstrated with laser therapy, which involves the removal of successive layers of skin to expose the intradermal pigment, which is subsequently vaporized
66
Special concern when treating gunpowder or fireworks accidents
The surgeon should take great care while administering Nd:YAG laser treatments in any patient who has sustained injuries resulting from a gunpowder or fireworks accident, as the unburned, embedded gunpowder can actually combust during treatment, leading to unacceptable scarring.
67
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Which of the following findings is more likely in patients who undergo resurfacing with the erbium:YAG laser than in patients treated with the carbon dioxide laser?
(A) Erythema
(B) Hypopigmentation
(C) Scarring
(D) Skin tightening
(E) Transudate wound
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(E) Transudate wound
Scarring may occur with any type of laser and is related to the amount of heat generated from the laser, also known as its pulse.
Likewise, skin tightening occurs with both the Er:YAG and the carbon dioxide laser.
68
Treatment of choice for ablative resurfacing of the skin
The erbium:YAG (Er:YAG) laser is now the treatment of choice for ablative resurfacing of the skin. This laser emits light at a wavelength of 2940 nanometers (nm) and is absorbed by water within the epidermis a minimum of 10 times more efficiently than the carbon dioxide laser.
69
Dermal heating with YAG
The YAG laser emits light at a wavelength of 2940 nanometers (nm) and is absorbed by water within the epidermis a minimum of 10 times more efficiently than the carbon dioxide laser. The decreased dermal heating that occurs during treatment with the Er:YAG laser results in minimallong-term contraction of the dermis, but produces a transudative wound once the epidermis has been eliminated. The transudation becomes more profuse as the surgeon ablates deeper into the dermis.
70
Mechanism of action of the Er:YAG laser
Because the mechanism of action of the Er:YAG laser is photomechanical rather than photothermal, coagulation necrosis is limited and hyperemia is decreased. As a result, permanent hypopigmentation occurs in less than 5% of patients undergoing treatment with the Er:YAG laser. (Vs permanent hypo pigmentation in as many as 40% of patients undergoing carbon dioxide laser tx)
71
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Which of the following laser wavelengths has the greatest affinity for water?
(A) 585 nm
(B) 1064 nm
(C) 1320 nm
(D) 2940 nm
(E) 10,600 nm
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(D) 2940 nm
72
Er: YAG overview
The erbium:YAG (Er:YAG) laser emits light at a wavelength of 2940 nanometers (nm) and is absorbed by water within the epidermis a minimum of 10 times more efficiently than the carbon dioxide laser. Its mechanism of action involves photomechanical injury to the targeted tissue
73
Utility of the 585-nm pulsed-dye laser
The 585-nm pulsed-dye laser is used in the treatment of cutaneous vascular lesions
74
Utility of the double Q-switched Nd:YAG laser
The double Q-switched Nd:YAG laser is appropriate for the removal of hair or tattoos
75
Utility of the millisecond pulsed Nd:YAG laser
the millisecond pulsed Nd:YAG laser is indicated for treatment of vascular lesions
76
Utility of the 1320-nm wavelength
The 1320-nm wavelength is incorporated by many nonablative lasers that stimulate collagen production within the dermis. Although the target of these 1320-nm lasers is water, they have 50% less affinity for water than the Er:YAG laser
77
The carbon dioxide laser emits light at a wavelength of:
The carbon dioxide laser emits light at a wavelength of 10,600 nm.
78
The carbon dioxide laser produced _______ injury
The carbon dioxide laser produces photothermal injury. I
79
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Which of the following characteristics of the carbon dioxide laser best explains the greater level of peripheral dermal injury that occurs with this laser than with the Er:YAG laser?
(A) Decreased thermal diffusion
(B) Less collagen contraction
(C) Limited coagulative necrosis
(D) Lower affinity for water
(E) Shorter pulse duration
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(D) Lower affinity for water
80
Er:YAG laser vs Carbon dioxide laser
Although the carbon dioxide and Er:YAG lasers are both absorbed by water, the Er:YAG laser has an affinity for water that is ten times greater than the carbon dioxide laser. It has an efficient rate of absorption and a short duration of exposure; each pass of the laser results in only minimal tissue necrosis. In addition, the pulse duration of the Er:YAG laser is shorter. Because it produces limited coagulative necrosis, the effect of erbium is photomechanical, rather than photothermal, and the amount of collagen contraction is much less than that produced by the carbon dioxide laser.
81
Benefits of carbon dioxide laser over Er:YAG
Although the Er:YAG laser is well suited for fine ablation of the epidermis, it does not stimulate continued collagen remodeling.In contrast, the carbon dioxide laser produces a greater thermal effect on surrounding tissue and subsequent collateral injury, resulting in continued remodeling of collagen and a greater overall cosmetic improvement.
82
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A 17-year-old girl wishes to undergo removal of a butterfly-shaped tattoo that was professionally drawn in black ink on the skin overlying the right scapula. Which of the following lasers is most appropriate for removal?
(A) Carbon dioxide
(B) Copper vapor
(C) Erbium
(D) Nd:YAG
(E) Pulsed dye
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(D) Nd:YAG
83
Nd:YAG laser
The Nd:YAG laser emits light at a wavelength of 1064 nm and is preferentially absorbed by dark pigments, such as blue and black. It penetrates the skin to a depth of 2 to 6 mm, which will result in disruption of the tattoo pigment. Multiple treatments are typically required
84
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In a 5-year-old child who has a large capillary vascular malformation on the upper eyelid, which of the following lasers is most appropriate for removal?
(A) Alexandrite
(B) Carbon dioxide
(C) Nd:YAG
(D) Pulsed dye
(E) Q-switched ruby
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(D) Pulsed dye
85
Removal of the capillary vascular malformation, or port-wine stain, is best accomplished with use of a ________________ laser.
Removal of the capillary vascular malformation, or port-wine stain, is best accomplished with use of a flashlamp-pumped pulsed dye laser.
86
Flashlamp-pumped pulsed dye laser
The flashlamp-pumped pulsed dye laser delivers short pulses (450 msec) of 585 nm of yellow light that are selectively absorbed byhemoglobin and oxyhemoglobin chromophores
87
Vascular lasers and selective thermolysis
Vascular lasers and other pigment-specific lasers function according to the principle of selective photothermolysis, which describes the resultant localized tissue damage. Target tissue damage occurs when light of a particular wavelength is delivered to and absorbed by the target, but not the surrounding tissue, during a pulse duration less than or equal to the thermal relaxation time of the target.
88
A 23-year-old man who has the blue-green tattoo shown in the above photograph wishes to undergo tattoo removal. Which of the following is the most appropriate management?
(A) Carbon dioxide laser ablation
(B) Serial excision
(C) Excision and full-thickness skin grafting
(D) Multiple treatments with the Q-switched Nd:YAG laser
(E) Dermabrasion
(D) Multiple treatments with the Q-switched Nd:YAG laser
89
Best laser(s) for removal of blue-green tattoo pigments
The Q-switched Nd:YAG and alexandrite lasers are best used for removal of blue-green tattoo pigments.
90
Best laser(s) for removal of red,brown,orange tattoo pigments
The Nd:YAG laser works best for red, brown, and orange pigments.
91
Best laser(s) for removal of violet-purple tattoo pigments
The Q-switched ruby laser is used to remove tattoos with violet and purple pigments.
92
A 55-year-old woman with moderate sun damage to facial skin and facial wrinkles comes to the office for laser skin resurfacing. Which of the following is the most appropriate management regarding respiratory protection from the laser smoke plume?
A) High-efficiency smoke evacuator placed 20 to 25 cm away from the site of the laser plume
B) High-efficiency smoke evacuator placed within 1 to 2 cm of the smoke plume
C) Standard surgical mask alone
D) Standard wall suction
E) No specialized equipment or protection is necessary
B) High-efficiency smoke
Along with ocular hazards and fire hazards, laser smoke plume is a significant occupational hazard, which is often ignored when lasers are used. There are numerous substances, some carcinogenic and mutagenic, released during laser pyrolysis of tissue. Viable skin bacteria, including coagulase-negative Staphylococcus, Corynebacterium, and Neisseria, have been recovered from the laser plume following laser skin resurfacing. In addition, intact viral DNA, particularly of human papillomavirus, has been isolated from carbon dioxide laser plume. Most surgical masks only filter particles that are 5 microns in diameter or larger; however, 77% of particles in the laser plume are 1 micron or smaller. Therefore, well-fitted high-filtration or laser masks should be used instead of standard surgical masks. A high-efficiency smoke evacuator should also be used, but it needs to be within 1 to 2 cm of the laser smoke plume source. The effectiveness of the smoke evacuator is decreased from 99 to 50% as the distance from the laser-treated site is increased from 1 to 2 cm, so 20 to 25 cm away is ineffective.
93
Which of the following is most effective in decreasing the risk of fire when using a carbon dioxide laser for facial resurfacing?
A) Clamp the laser cord to surgical drapes
B) Intubate laser patients to prevent oxygen accumulation on the field
C) Provide supplemental oxygen with a nasopharyngeal cannula
D) Use conscious sedation, nerve blocks, and no supplemental oxygen
E) Use foot pedals only for activating the laser
D) Use conscious sedation, nerve blocks, and no supplemental oxygen
Carbon dioxide laser treatments can cause operating room fires. Several papers have shown that a nasopharyngeal oxygen delivery can decrease oxygen levels in the operative field when it is required, but the best way to decrease the level of oxygen on the field is not to use it. Foot pedals can be accidentally activated and should be avoided. Clamping the laser cord can damage the fibers and ignite the laser fiber sheath. Laser skin surfacing can be accomplished without intubation.
94
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A 24-year-old woman comes to the office because of a capillary malformation of the right cheek. Which of the following lasers is the most appropriate treatment in this patient?
A) Carbon dioxide laser (10,200 nm)
B) Er:YAG (2940 nm)
C) Nd:YAG (1064 nm)
D) Pulsed-dye (585 nm)
E) Q-switched ruby (694 nm)
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D) Pulsed-dye (585 nm)
The chromophore for the pulsed-dye laser at a wavelength of 585 nm is oxyhemoglobin. Thus, this laser is best suited to treat vascular lesions. Rhytides, acne scars, and dyschromias can also be managed by ablative resurfacing techniques, such as a carbon dioxide laser, which is absorbed by water. Er:YAG has a wavelength of 2940 nm and is absorbed by water. This laser causes less collateral thermal necrosis than a carbon dioxide laser. Acne scarring is best managed with infrared lasers at wavelengths of 1064 to 1540 nm. These include the Nd:YAG, diode, and erbium lasers. Tattoos are best managed with a Q-switched ruby laser at a wavelength of 694 nm, which is absorbed by melanin and carbon pigments.
95
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A 54-year-old woman comes to the office because of severe facial rhytides and photodamage. Examination shows Fitzpatrick skin type III. Ablative laser resurfacing is planned. Which of the following is the most likely complication of laser resurfacing in this patient?
A) Acneiform eruption
B) Bacterial infection
C) Erythema
D) Hyperpigmentation
E) Scarring
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D) Hyperpigmentation
Hyperpigmentation is the most common adverse effect of laser resurfacing. It occurs in 36% of patients and is most common in people with Fitzpatrick skin Types III to VI. Treatment consists of hydroquinone and tretinoin. Sun exposure should be avoided. Rates of hyperpigmentation can be reduced in those pretreated with retinoic acid and bleaching agents. While hyperpigmentation can be permanent, with proper treatment it usually resolves within a few months.
Acne can occur post-laser treatment. It is especially common in patients with a prior history and should be treated with standard acne therapies. Infection risk from bacteria is minimized with prophylactic antibiotics and good topical care. Viral herpes simplex outbreaks can occur in those with and without a history. Antiviral prophylaxis is now used in all patients undergoing laser resurfacing. Yeast infections are also a possible infectious complication. These respond well to systemic antifungals. Scarring can occur with improper technique that causes excessive thermal damage (i.e., too many passes and excessive energy fluencies). Areas that develop scarring can be treated with topical and intralesional corticosteroids, silicone sheeting, and pulsed-dye laser. Erythema is not considered a complication and is a normal part of the healing process. It can last 1 to 4 months depending on the type of laser used.
96
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A 46-year-old woman comes to the office for evaluation of persistent erythema 2 weeks after she underwent full-face carbon dioxide laser resurfacing. Which of the following topical treatments is most appropriate to decrease this patient's postoperative erythema?
A) Amoxicillin
B) Ascorbic acid
C) Hydroquinone
D) Prednisone
E) Valacyclovir
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B) Ascorbic acid
Erythema following laser resurfacing is an anticipated consequence of therapy. Posttreatment erythema is more severe and of longer duration with carbon dioxide laser resurfacing when compared to the fractionated carbon dioxide or Er:YAG laser. Postoperative topical application of ascorbic acid has been shown to decrease the duration as well as the severity of erythema. Topical therapy with ascorbic acid should be applied following reepithelialization. Antibiotics or antivirals have not been shown to decrease erythema. Hydroquinone is a skin bleaching agent that does not treat erythema. Topical corticosteroids postoperatively may delay reepithelialization and have not been associated with a decrease in erythema.
97
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A 38-year-old woman comes for consultation regarding facial laser resurfacing. Physical examination shows Fitzpatrick Type III skin with facial dyschromia. Which of the following is the most likely side effect of fractional carbon dioxide laser resurfacing in this patient?
A ) Contact dermatitis
B ) Dermal scarring
C ) Ectropion
D ) Hyperpigmentation
E ) Rosacea
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D ) Hyperpigmentation
Pigmented skin, Fitzpatrick Type III or IV, tends to absorb about 40% more laser energy than nonpigmented skin. Thermal damage can extend beyond the area of treatment. For these reasons, physicians should be aware of the side effects and complications of ablative laser treatment in pigmented skin.
The most common side effect is hyperpigmentation. Hyperpigmentation usually occurs within 6 weeks to 6 months following laser ablation and is present in 100% of darkly skinned patients. Hyperpigmentation is most often transient and can persist for 9 months to 1 year. Recommended treatment is hydroquinone.
Contact dermatitis can occur secondary to topical antibiotic therapy such as neomycin or bacitracin. Less common side effects include dermal scarring, herpetic infections, or ectropion.
98
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A 22-year-old man comes for consultation regarding laser removal of a tattoo located on the upper lateral arm. He said his friend tattooed him 6 years ago using a sewing needle and black pen ink. Physical examination shows Fitzpatrick Type IV skin. Which of the following laser treatments is most likely to decrease the risk of scarring in this patient?
A ) Argon-pumped tunable dye
B ) Carbon dioxide
C ) Er:YAG
D ) Flash lamp-pumped pulsed-dye
E ) Q-switched ruby
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E ) Q-switched ruby
Most amateur tattoos are characterized by pigment deposited at variable, sometimes excessive depths compared with those produced by a professional apparatus. This may compromise the ability to erase the tattoo in a single session or at all without resorting to more traditional measures, such as direct excision. The chromophore of the carbon dioxide laser is water; therefore, it will indiscriminately destroy unaffected skin, as well as the skin containing tattoo pigment. Fitzpatrick Type IV skin is that which, while resistant to sunburn, is more likely to demonstrate a genetic predisposition to hypertrophic scarring. Ablative laser treatment has been shown to adversely affect the risk of hypertrophism. Current safety guidelines require that all individuals present during laser therapy don appropriate eyewear, selected according to the laser wavelength. Q-switched lasers, including ruby, Nd:YAG, and alexandrite types, are based on the principle of selective photothermolysis. They are suited for removal of black tattoo pigments as well as a variety of colors while minimizing the risk of scar.
99
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An 8-month-old boy is brought to the office for evaluation of a capillary malformation involving the right side of the chest and right cheek. Physical examination shows red cutaneous discolorations in a dermatomal distribution. Which of the following lasers is most appropriate to treat this condition?
A ) Carbon dioxide laser (10,200 nm)
B ) Nd:YAG (1064 nm)
C ) Pulsed-dye (585 nm)
D ) Q-switched alexandrite (755 nm)
E ) Q-switched ruby (694 nm)
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C ) Pulsed-dye (585 nm)
Pulsed-dye laser with epidermal cooling remains the standard means of treating port-wine stains in the pediatric population. Intense pulsed-light devices have also been used with some effectiveness. The principles of selective thermolysis play a critical role in optimizing the treatment of port-wine stains. Oxyhemoglobin serves as the target chromophore, exhibiting three absorption peaks (418, 542, and 577 nm). Currently, the 585-nm and 595-nm pulsed-dye lasers appear to be the most popular choices and are most effective because of their proximity to an absorption peak and even deeper penetration. Depth of penetration is further enhanced by using a larger spot size (10 mm).
Neodymium: yttrium-aluminum-garnet (Nd:YAG) laser treatment has surfaced as an effective treatment for superficial venous malformations. The Q-switched alexandrite laser is effective in tattoo removal of black, blue, and green inks. The Q-switched ruby laser is effective in removing tattoos with minimal scarring and removes black, blue-black, and green ink.
