INTRODUCTION
Ablative skin resurfacing (ASR) provides significant improvement
in reversing signs of cutaneous photoaged
skin1-6 but is limited by adverse postoperative sequelae
such as extended recovery times, risk of infection, scarring,
and persistent pigmentary changes.7,8 In contrast to ASR, which
aims to achieve homogeneous thermal damage at a particular
depth within the skin,9 ablative fractional photothermolysis
produces arrays of microscopic thermal zones, creating small
columns of thermal injury without injuring surrounding tissue.
10 This fractionated skin injury leaves small bridges of normal
skin intact, which is thought to act as a natural bandage
promoting reepithelialization within less than 48 hours with no
loss of epithermal barrier function.1,11-13
Ultrapulse-mode fractional carbon dioxide (UPCO2) and superpulse-
mode fractional carbon dioxide (SPCO2) are 2 commonly
used modes in treating photoaged skin. Theoretically, UPCO2 delivers
a "flat-top" pulse beam, with a higher fluence and shorter
pulse duration, while SPCO2 delivers a stack of superpulse-shaped
beams, which at the beginning of the pulse, produce a burst of energy
that tails off throughout the duration of the pulse.14 Although
the peak fluence of SPCO2 is only one third of UPCO2, the pulse
duration is 3 times longer. It is postulated that the longer dwelling
time compensates for the insufficiency of the pulse energy so
that epidermal ablation can occur. We designed a split-face study
to compare the efficacy and side effects of UPCO2 and SPCO2 in
treating photoaged skin in Chinese subjects.
PATIENTS AND METHODS
Subjects
Eighteen female Chinese subjects (mean ± standard deviation
age, 50±5.03 years; Fitzpatrick skin type IV) with obvious
photoaged skin manifested as fine rhytids, irregular pigmentation,
wrinkles, and skin laxity were enrolled from November
2009 to February 2010.15 The exclusion criteria were patients
with concomitant treatments, pregnancy, skin cancer, a history
of keloid, vitiligo, recurrent facial herpes simplex infection,
diabetes, coagulation malfunction, infectious lesions, recent
extensive sun exposure, and oral administration of photosensitive
drugs.16 The study was approved by the Medical Ethics and
Human Research Committee of China Medical University. All
patients were informed of the risks, benefits, and possible complications
of the treatment before enrollment into the study.
Informed consent was obtained from each patient.
Equipment
The UPCO2 treatment was performed with the DeepFXTM handpiece
of the UltraPulse CO2 fractionated laser (Lumenis Inc,
