Biomedical Engineering Reference
In-Depth Information
submentum, showed better results, suggesting a dose-response
relationship.
Nonetheless, Prado and colleagues conducted a prospective
randomized, double-blind controlled clinical trial comparing
LAL with conventional suction lipoplasty in 25 patients and
found no major clinical differences between conventional suc-
tion lipoplasty and laser-assisted liposuction (41). They used
the SmartLipo System and applied 500 J for each area equiva-
lent to the size of the patient's “palm” of the hand on one side
followed by aspiration with a 3-mm cannula. The contralateral
side was also infi ltrated with tumescent fl uid and aspirated
with a 3-mm cannula. There was no difference in cosmetic
results, ecchymosis, edema, and retraction between the two
groups. There was less pain in the LAL side; however, surgical
time was longer for the LAL side (median 60 minutes; range
45-80 minutes) compared with the suction-assisted lipoplasty
side (median 45 minutes; range 40-80 minutes).
Goldman and colleagues have examined the effect of the
1064-nm LAL platform in several treatment areas. In one
study, 82 subjects with submental lipodystrophy were treated
using a 1064-nm Nd:YAG laser, with 6-W power, 40-Hz fre-
quency, 150-mJ energy, and 100-µs pulse width parameters
(SmartLipo, Cynosure) (17). Histology was performed on fatty
tissue samples. Some patients received liposuction immedi-
ately following LAL. The histologic studies revealed coagula-
tion of small blood vessels, rupture of adipocytes, reorganization
of the reticular dermis, coagulation of collagen, and the app-
earance of channels produced by the laser action. However, the
fi nal results obtained with LAL were similar to the results uti-
lizing traditional liposuction. In a separate study by Goldman
and colleagues (19), laser liposuction using the 1064-nm
SmartLipo device was compared with liposuction alone in 28
female patients with skin fl accidity and lipodystrophy of the
arms. One arm in each patient was treated with laser liposuc-
tion followed by traditional liposuction. The contralateral arm
was treated with pretunneling of the SmartLipo device with no
optical fi ber, followed by traditional liposuction. Treatment
end points 3 months postprocedure included blinded, clinical
photographic comparisons and arm circumference measure-
ments. Arm circumference reduction was superior in the laser-
treated group compared with liposuction alone (
P
= 0.001).
Skin retraction in the laser-treated group versus liposuction
alone-treated group was 11.4% ± 3.17% versus 8.70% ± 2.40%,
respectively. These results complemented higher photographic
clinical outcome ratings in the laser- versus liposuction alone-
treated groups.
Another 1064-nm pulsed Nd-YAG device became available
for LAL in the US market in May 2008. Lipolite
TM
(Syneron,
Yokneam, Israel) consists of a variable pulse system (pulse
width of 100-800 ms) with a maximum power of 12 W, maxi-
mum pulse energy of 800 mJ/pulse, and a repetition rate up to
50 Hz. Energy is delivered with a 550-µm fi ber ensheathed
within a 1.2-mm microcannula. Like the SmartLipo system,
aspiration must be performed in a separate step following LAL.
Therefore, LAL using an Nd:YAG laser has been shown to be
effective and safe in previous studies, with apparent advan-
tages over traditional liposuction such as fast patient recovery
and a possible skin tightening effect. A longer operative time is
also a minor relative drawback, which needs to be measured
against the possible advantages. Some authors defend that
early reports regarding the lack of effi cacy of skin tightening
were related to the steep learning curve of the procedure, inad-
equate energy delivery, or insuffi cient heat application (42).
However, further studies are still needed to standardize meth-
ods that will optimize results, safety, and effi cacy.
The 1320-nm Device
This wavelength is effi ciently absorbed by fat and water
(22,26) and targets mostly dermal and subcutaneous colla-
gen, water-containing adipocytes, and collagen-bound water
(33). The 1320-nm device may provide less collateral tissue
damage, as energy deposition to tissues is concentrated
around the laser tip (22,26). Because of its preferential target-
ing of water, the 1320-nm laser device may allow for greater
tissue tightening (22).
The 1320-nm device was FDA approved in January 2008 and
marketed as CoolLipo (CoolTouch, Roseville, California,
USA). CoolLipo delivers a maximum of 25 W through 200-,
320-, and 500-µm fi bers. The pulsed fi ring is delivered with a
100-ms pulse width at 20-50 Hz (14). A dual-port microcan-
nula allows both LAL and aspiration to occur simultaneously
(Figs. 14.2-14.6).
One study has examined the clinical effects of the 1320-nm
device to the 1064-nm and multiplex (1064 + 1320 nm) devices
(28). Mild-to-moderate improvement in skin laxity was noted
in 10 patients undergoing LAL of the arms, abdomen, fl anks,
or thighs with the 1320-nm device at 10 W, 40-50 Hz, followed
by aspiration. However, there was not a control of liposuction
only to determine whether the improvement in skin laxity was
much greater than liposuction alone.
Multiplex Devices
The 1064/1320-nm multiplex device (SmartLipo MPX, Cyno-
sure, Inc.) incorporates sequential fi ring of the dual wave-
lengths although either wavelength can be fi red alone (14).
The newer platform also includes a handpiece with motion-
sensing feedback, termed “SmartSense,” allowing an automatic
shut-off mechanism when maximum temperatures are
reached. The platform is capable of fi ring a maximum of 20 W
at 1064 nm and 12 W at 1320 nm through a 600-µm fi ber con-
tained within a 1.0- to 1.5-mm microcannula (14).
The scientifi c premise for combining the 1064- and 1320-nm
wavelengths is to exploit their individual properties and allow
for them to act synergistically, particularly in regard to hemo-
stasis. The 1320-nm wavelength converts hemoglobin to met-
hemoglobin (22). The 1064 nm not only targets oxygenated
hemoglobin but also has a great affi nity to methemoglobin,
thereby enhancing the effects of the 1320-nm fi ring (22).
McBean and Katz evaluated the safety and effi cacy of the
1064/1320-nm (SmartLipo MPX
TM
, Cynosure, Inc.) system for
lipolysis of localized fat and skin tightening in 20 patients (27).
Five of the subjects had 4 × 4 cm temporary India ink tattoos
placed at treatment sites and the tattooed areas were measured
at baseline and 1-month and 3-month intervals. Suction aspi-
ration followed laser treatment to remove the liquefi ed adipose
tissue. Independent observers found reduction in localized fat
in all patients (76-100% improvement in 85% of subjects and
51-75% improvement in 15% of subjects) with no adverse
events. India ink tattoo maps demonstrated an 18% decrease
in surface area indicating a signifi cant skin tightening effect.
