Laser and Light Treatment of Acquired and Congenital Vascular Lesions Flashcards
Lasers produce selective photocoagulation of vessels using wavelengths of light that are well absorbed by haemoglobin.
T
Lasers produce selective photocoagulation of vessels using pulse durations equal to or longer than the thermal relaxation time (or cooling time) of the vessels.
F Equal to or shorter than thermal relaxation time.
Larger-diameter and deeper vessels require shorter wavelengths of light and shorter pulse durations.
F Longer wavelength and longer pulse durations.
Lasers and light devices used to treat vascular lesions include KTP, pulsed-dye, alexandrite, diodie and Nd:YAG lasers, in addition to IPL.
T
Laser stands for Light Amplification by the Stimulated Emission of Radiation.
T
Fluence is measured in J/cm2.
T
The major chromophores in skin are haemoglobin and melanin.
F And water.
When targeting a vascular lesion, the wavelength of light chosen should be well absorbed by haemoglobin and poorly absorbed by melanin.
T
Selective heating of the laser target is produced when the energy is deposited at a rate faster than the rate for cooling of the target structure.
T
Pulsed KTP laser has a wavelength of 532nm.
T
Pulsed dye laser has a wavelength of 595nm.
F 585nm (long-pulsed dye is 585-600nm).
Long-pulsed alexandrite laser has a wavelength of 755nm.
T
Diode laser uses 800, 810 or 840nm wavelength.
F 800, 810 or 940nm.
Long-pulsed Nd:YAG laser has a wavelength of 1064nm.
T
IPL uses a wavelength of 515-920nm.
F 515-1200nm.
For a given wavelength of light, the optical penetration into skin depends on absorption and scattering.
T
The most penetrating wavelengths are in the 650-1200nm red and near-infrared region.
T
Longer wavelengths (600-1200nm) penetrate deeper, but with more scattering
F Deeper with less scattering
The least penetrating wavelengths are in the far UV, where protein absorption dominates, and the far-infrared, where water absorption dominates.
T
The depth of penetration gradually decreases with longer wavelengths.
F Increases with longer wavelengths.
With smaller spot sizes, a greater fraction of photons scatter outside the beam area and are rendered ineffective.
T
Cooling the skin does not effect tissue injury caused by laser procedures.
F Cooling before/during/after reduces tissue injury.
Cooling can be achieved by using a liquid cryogen spray during treatments
T
Pulsed-dye laser produces transient blue-black purpura due to haemorrhage and a delayed vasculitis.
T
For v essels 10-50microm in diameter, the thermal relaxation time would be 0.1-10ms, with an average of 1.2ms
T
Pulsed-KTP lasers emit in the green light spectrum.
T
Longer pulse durations increase photomechanical injury and post-treatment purpura.
F Reduce.
Lasers with near-infrared wavelengths are not suitable for treating larger vascular anomalies or larger leg veins.
F Alexandrite, diode and Nd:YAG used for this.
Vascular lasers can be used for capillary malformations, haemangiomas, venous malformations, telangiectasias, facial erythema, cherry angiomas, venous lakes and poikiloderma of Civatte.
T
Striae distensae cannot be treated with vascular laser.
F Striae rubra shows best response.
The hypopigmentation of striae distensae responds well to vascular laser.
F No effect.
Port wine stains can regress.
F Never regress.
Port wine stains darken in colour and become increasingly nodular with age.
T
The hypertrophy or nodularity of a PWS are associated with a risk of spontaneous bleeding or haemorrhage with injury to the site.
T
PWS should not be treated ideally until adulthood.
F Childhood better.
Treatment of PWS in early life enables more rapid clearing, however there may be partial return of the PWS 5-10 years after treatment.
T
Greater PWS clearance in children is attributed to thinner skin allowing better laser penetration, smaller vessel diameter, and smaller lesional surface area.
T
Gradual clearing of PWS is produced with successive PDL treatments usually performed at 2-4 week intervals.
F 4-6 week intervals.
PDL can be safely used in skin types I-IV.
T
With PDL, longer wavelengths and longer durations improve PWS clearance.
T Longer wavelengths provide more deeply penetrating light to target deeper vessels.
The response of a PWS to PDL treatment depends on its size, anatomic location and the types of vessels that comprise the lesion
T
PWS that are present in the central facial area or in a V2 dermatomal distribution respond faster than PWSs located elsewhere on the head and neck.
F More slowly.
PWS on extremities respond more slowly to laser therapy than lesions on the trunk, and lesions on the distal extremity respond the slowest.
T
Smaller PWSs respond better to PDL.
T
The best response to PDL is seen in PWSs located deeper, with smaller diameter vessels.
F Superficially located, larger-diameter vessels
Vessel morphology does not correlate with PWS colour.
F Pink = smaller vessel, purple = larger vessel.
Red PWS lesions are composed of more superficially located vessels than pink or purple ones.
T
Red coloured PWSs respond poorly to laser, while pink coloured PWSs respond better.
F Red better, pink worse.
Even slowly responsive PWSs continue to clear with repetitive PDL treatment with no increased risk of adverse effects.
T
PDL treatment for PWS during infancy is not recommended.
F Safe and rapid clearance possible.
Treatment of PWS with PDL is usually performed with the smallest spot size available to prevent reticulation.
F Largest spot size.
PDL treatment of PWS should be performed with the lowest fluence possible that produces purpura without tissue graying or whitening.
T
Improved technology in skin cooling has been a major advancement in treatment of PWS
T
Appropriate cooling can be achieved by applying millisecond-duration cryogen spurts, preceding each laser pulse with maintenance of the temperature of the laser-heated dermal vessels
T
There may be a delayed final tissue reaction after PDL, so the patient should be observed for several minutes after treatment.
T
Intense purpura develops 7-10 days after PDL.
F Immediately.
The post-treatment purpura associated with PDL takes 2-4 weeks to resolve.
F 7-10 days.
Following resolution of purpura after PDL, lesional lightening takes place over 4-8 weeks, when repeat treatments are performed.
T
Subsequent treatment sessions with PDL should be delayed until all traces of relative erythema have subsided.
T
Treatment should be performed with the lowest possible fluence that produces purpure without tissue graying or whitening
T
When tissue graying is encountered, skin should be cooling immediately with ice-packs to avoid epidermal necrosis, crusting and potential scarring
T
Subsequent treatment sessions for PWS can continue despite the development of reactive erythema
F Should be delayed until all traces of reactive erythema have subsided
IPL devices are broadband filtered xenon flashlamps that work on the principles of selective photothermolysis.
T
The IPL emission spectrum of 515-1200nm is adjusted with the use of a series of cut-off filters.
T
The pulse duration of IPL ranges from approximately 100 to 200ms.
F 0.5 to 100ms
IPL is the treatment of choice for PWS.
F PDL.
IPL can be used to treat PDL-resistant PWS.
T
KTP laser provides relatively equal absorption and depth of penetration to the PDL, but the overall rate of side effects is higher due to its higher absorption by melanin.
T
Long-pulsed alexandrite and Nd:YAG lasers are effective in treating hypertrophic or nodular PWS.
T
The alexandrite laser can produce bulk heating and necrosis if used too aggressively for the treatment of PWS.
F This is true for Nd:YAG.
The Nd:YAG laser has a higher incidence of post-inflammatory hyperpigmentation compared to the PDL.
F This is true for the alexandrite laser.
Haemangiomas occur in females three times as often as males.
T
60-70% of haemangiomas occur on the trunk.
F Head and neck.
Haemangiomas are composed of numerous small blood vessels and infiltrating vascular endothelial cells that express GLUT1.
T
Infantile haemangiomas initially appear as white or pink macules, or telangiectasia with surrounding vasoconstriction.
T
Approximately 5% of patients with haemangiomas have incomplete involution.
F 50%
Superficial haemangiomas appear as bright red vascular papules or plaques when fully developed.
T
Deep haemangiomas appear as bluish-coloured nodules within the skin with only a subcutaneous component.
T
Haemangiomas may be only either superficial or deeply located.
F Compound haemangiomas occur.
Focal haemangiomas account for 85% of lesions.
T
Focal haemangiomas occur on any site in random distribution.
F Occur along lines of embryological fusion.
Diffuse hamangiomas occur on any body site in random distribution.
F Segmental distribution.
Diffuse haemangiomas tend to be deep lesions.
F Superficial or compound.
Diffuse haemangiomas carry a high risk of ulceration.
T
Laser therapy for haemangiomas can only be performed once the lesion has involuted.
F Perform during both proliferation and involution.
PDL prevent haemangioma enlargement, promote involution, induce re-epithelialisation of ulcerations, and reduce ectasia.
T
Thin haemangiomas (
T
Haemangiomas treated early in the prodromal phase respond better than those treated during active proliferation.
T
Laser treatment usually slows the proliferation of the superficial component of haemangiomas and promotes early regression.
T
Haemangiomas should be treated using the same laser parameters as for PWS.
F Lower fluence, larger spot size.
Ulceration is not a common complication of haemangiomas.
F Most common complication.
Approximately 12% of diffuse haemangiomas and 65% of focal haemangiomas ulcerate.
F 12% focal, 65% diffuse.
Ulcerated haemangiomas usually result in a scar.
T
Ulcerated haemangiomas respond well to PDL if the ulceration is limited and the haemangioma is not undergoing rapid proliferation.
T
Segmental haemangioms are best treated in the early growth phase with PDL.
F Laser can cause ulceration in this context.
Pulsed-dye lasers can greatly effect the subcutaneous component of haemangiomas.
F Little effect due limited depth of penetration.
CO2 lasers and long-/short-pulsed Er:YAG lasers produce excellent improvement in the atrophic scarring and textural change that accompany haemangioma involution.
T
The peak incidence of spider angiomata between the ages of 30 and 40 years old.
F 7-10yo.
Treatment of telangiectasiae with PDL is performed by applying contiguous laser pulses with no overlap.
F Approx. 10% overlap.
Nd:YAG can be very safely used around the nasal ala to treat telangiectasiae.
F Need proper skin cooling and avoidance of pulse stacking to prevent epidermal damage.
Long-pulsed Nd:YAG lasers are particularly useful for the treatment of larger-calibre paranasal vessels.
T
Nd:YAG treatment of visible facial veins is limited to those outside the orbital rim.
T Risk of damage to eye with this deeply penetrating wavelength.
IPL cannot be used to treat facial telangiectasiae.
F
Laser treatment of poikiloderma should be delayed for a minimum of 4 weeks following sun exposure.
T
Compared to the treatment of telangiectasia, fluences for poikiloderma should be lowered by approximately 50-70% to avoid adverse effects.
F 25-30%.
IPL systems for the treatment of poikiloderma generally use 515-550nm cut-off filters.
T
During IPL treatment, a thin layer of gel is applied to the skin surface to aid in skin cooling.
T
Erythema and oedema may be present for 2-3 weeks following laser or IPL treatment of poikiloderma.
F 2-3 days.
PDL is not suitable for the treatment of scars.
F Use for erythematous and hypertrophic scars.
PDL treatment for scars reduces erythema, scar height and surface texture changes.
T
Multiple PDL treatment sessions are often necessary for scars.
T
Scars should be treated with lasers in intervals of 6-8 weeks.
T
PDL are not very effective in treating condyloma acuminata, plantar warts, periungual wart, flat warts and verrucae vulgaris.
T
Recalcitrant warts post-laser treatment are best treated with a different method.
F Require 3-4 treatments at 3-4 week intervals.
Laser and IPL beams should always be directed away from the orbit when treating in the eye region.
T
PDL is capable of igniting a fire in the presence of oxygen and nitrous oxide.
T
Topical anaesthetic cannot be used with vascular lasers and light sources.
F
With PDL, larger spot sizes are less efficacious and increase the potential for reticulation.
F Greater efficacy, reduce potential for reticulation between Rx sessions.
With PDL, post-treatment purpura is most intense with the 0.45ms pulse duration and requires approx. 10 days for resolution.
T
With epidermal cooling techniques, blistering or crusting after PDL occurs rarely.
T
At pulse durations greater than 6ms, purpura is not produced with PDL.
T Urticarial papules resolve over several hrs.
Most vascular lesions only require one treatment session.
F Multiple Rx sessions.
Suntanned individuals can be treated with PDL and KTP laser.
F Risk of absorption by epidermal pigment.
Facial telangiectasia and erythema respond well to millisecond-duration KTP lasers.
T
Patients with skin types V and VI can be treated with KTP laser.
F
Following treatment with KTP laser, there may be erythema and urticarial oedema of the treated skin lasting up to 24 hours.
T
Scarring can occur after KTP laser due to excessive fluence, overlapping of laser pulses, or in adequate skin cooling, which results in non-selective thermal damage to the epidermis/dermis.
T
Nd:YAG laser is the first-line device for treatment of superficial telangiectasia-
F
Larger paranasal and periauricular telangiectasia and venulectasia, that may not clear with green and yellow light, don’t respond well to Nd:YAG laser.
F Do respond well due to its greater depth of penetration.
The Nd:YAG laser produces bulk tissue heating.
T
Nd:YAG laser pulses can be safely stacked.
F Never – leads to ulceration and necrosis.
IPL uses a large rectangular footprint.
T
With IPL, shorter wavelength filters (515nm) and the single pulse mode are used on skin type I with fine superficial vessels.
T
With IPL, larger and deeper vessels are treated with longer cut-off filters (570 and 590nm) and double or triple pulse modes.
T
With IPL, shorter wavelength and shorter interpulse delays are used for darker skin types.
F Longer wavelength and interpulse delay.
Gel is not needed when treating with IPL.
F
Pulse durations of 10ms or higher are generally required to avoid purpura formation.
T
In contrast to treatment for telangiectasia, fluences should be lowered by 25-30% to avoid adverse effects in treating poikiloderma
T
PDL can be applied to treat hypertrophic scars but have a poor response
T good response (57-83%)
Pulsed dye lasers are very effective in treating the cutaneous lesions of HPV
T Via thermal alteration of the virally infected tissue
Low fluence pulsed-dye laser therapy also improves the appearance of striae
T
