Multiple diode lasers are now available, and differentsystems can emit infrared light at a variety ofwavelengths, including 800, 810, 940, and 980 nm. All of these devices are capable of being absorbed bythe tertiary hemoglobin peak and can be effective intreating leg telangiectases. The longer diode laserwavelengths penetrate more deeply than yellowlight and are poorly absorbed by melanin, but theyalso have limited but significant hemoglobin absorption.For that reason, the 980-nm diode lasercan be safely used in patients with skin typesI to IV skin.
The 800-nm diode can also be used to provideeffective treatment of leg blood vessels by usingstacked pulses (5–8 stacked pulses), a 50-ms pulseduration, a 3-mm spot size, and fluences of 210 to336 J/cm2. Using up to three separate treatments, itwas possible to achieve 50% to 74% improvementin 60% of patients (6/10).
The 810-nm pulsed diode used with a fluenceof 80 to 100 J/cm2, a 12-mm spot size, and a60-ms pulse duration demonstrated complete clearanceof leg vessels in 15 of 35 patients after asingle treatment,33 although at 6-month follow-up,only six patients maintained complete resolutionof vessels.
The 940-nm-diode laser had no effect when used totreat small blood vessels but was capable of improvinglarger visible leg veins of 0.8 to 1.4mm in88% of patients in one study.34 Twelve of 26 patients treated with the 940-nm diode laser at fluences of300 to 350 J/cm2, 40- to 70-ms pulse durations, anda 1-mm handpiece demonstrated greater than 75%clearance after 4 weeks.35 A study of 20 patientstreated with a single pass of the 940-nm diode laserat 300 to 350 J/cm2, 40 to 70-ms pulse duration,and a 1-mm spot achieved greater than 75% clearanceof treated blood vessels in 75% of patientsat 12 months of follow-up.
A study of the 980-nm diode used to treat blue legtelangiectases achieved greater than 50% clearanceof treated blood vessels in five of 10 patients.37One patient developed post-treatment hypopigmentation,and one developed telangiectatic matting. Bycombining 980-nm diode pulses with radiofrequencycurrent, lower fluences of 60 J/cm2 could beused for effective vessel clearance (50% of patientsachieved greater than 75% clearance rate at6 months), which may decrease the side-effectprofile.38 Biopsies showed contracted vessels withhyalinization, suggesting that the combineddiode and radiofrequency current therapy is aneffective treatment for leg veins. Combiningthe 915-nm diode with radiofrequency currentdemonstrated greater than 50% vessel clearance in75% of patients.
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