Abstract
Background and Objectives
Pulsed dye lasers (PDL) with extended pulse‐durations create new opportunities in the treatment of vascular lesions. Development of extended pulse methods requires understanding of tissue effects of extended pulse‐durations. We evaluated tissue effects of extended pulse‐duration PDL (EPDL) with cooling. Effects of increasing pulse‐duration, fluence, and multiple passes were evaluated to determine purpuric threshold and delayed purpuric response.
Study Design/Patients and Methods
Ten patients were treated with EPDL and air‐cooling on normal buttocks skin. Exposure pulse‐durations of 0.5, 2, 20, and 40 milliseconds and increasing fluences 3–20 J/cm^2^, pulse‐duration dependent. Exposures were evaluated 0.5, 1, and 24 or 48 hours determining purpuric threshold and side effects.
Results
Immediate purpuric threshold increased from 6.2 to 8, 10.4, and 13.8 J/cm^2^ at pulse‐durations of 0.5, 2, 20, and 40 milliseconds, respectively. Purpuric threshold dropped after 24 hours to 5.2, 7.1, 9.3, and 11.9 J/cm^2^, respectively. Multi‐pass treatment lowered purpuric threshold by 1 J/cm^2^. EPDL purpura resolved in less time than traditional PDL. No side effects were noted.
Conclusions
EPDL exhibits increasing purpuric threshold with increasing pulse‐durations, and risk of delayed onset of purpura. Lasers Surg. Med. 31:363–366, 2002. © 2002 Wiley‐Liss, Inc.