Hot Topics
External Ultrasound: New Clinical Applications
T
raditional therapeutic external ultrasound has
been used primarily for physical therapy. However, external ultrasound treatment is undergoing
a new birth in the field of cosmetic medicine and surgery.
Although carefully controlled and peer-reviewed scientific studies have been scarce, they are now emerging to
better define the benefits of these new uses.
Energy levels, frequency, and pulse patterns are the vital
parameters that aesthetic surgeons must understand for
the application of external ultrasound. Other practical
technique-related issues of genuine importance are pattern of movement of the sound head, duration of treatment, safety feedback loop design, and such matters as
avoiding treatment beyond the orbital rim and properly
sterilizing the sound head between patient treatments.
Five major areas for the potential use of external ultrasound are addressed here.
External Ultrasound-assisted Lipoplasty
Several recent studies have reviewed this application in
detail.1-3 A clear consensus on the clinical benefits of this
procedure has not yet emerged, but there appears to be a
reasonably consistent pattern of physician and patient
satisfaction. Optimal techniques and parameters have not
yet been defined.
External Ultrasonic Body Contouring for Cellulite
This controversial application is not yet well defined or
supported by well-controlled clinical trials.4 Our research
team evaluated external ultrasound for treatment of cellulite several years ago, but the results were not published because of concerns regarding the accuracy and
objectivity of the study model; some possible improvement was noted, however. Current evaluation of therapy
for cellulite is limited by the absence of a truly objective
experimental model for the study of cellulite therapies.
However, a more objective experimental model is now
being developed by our research group and by others,
and truly objective studies will soon be possible.
AESTHETIC
Tissue Tightening or the
Ultrasonic Face Lift
This potentially exciting
application has popular
appeal in light of the growing patient/consumer interest in nonsurgical anti-aging
procedures. As with the
David H. McDaniel, MD,
aforementioned applicaVirginia Beach, VA, is a boardtions, well-controlled and
certified dermatologist.
objective peer-reviewed
clinical trials from multiple
investigative sites have not yet emerged. Good objective
clinical documentation will be challenging for this
application. The use of continuous wave (CW) pulse
generation would certainly assist in elevating the tissue
temperature, but controlling it within a safe zone in temperature and depth is another matter. The depth can be
controlled by selecting the proper frequency, but obtaining the proper temperature and delivering it uniformly
across the entire face may prove a more elusive goal.
Currently, the nonablative CoolTouch laser (CoolTouch
Corp., Roseville, CA) and the Intense Pulsed Light Source
(ESC, Norwood, MA) are the gold standards for efficacy
and safety in photo rejuvenation. The CoolTouch offers
the best analogy to proposed ultrasonic skin tightening.
It is an erbium laser-like device that delivers precisely
controlled doses or packets of light energy to a relatively
well-controlled depth in the dermis. A miniature thermal
sensor aimed at the point of laser beam impact monitors
the temperature before and after the beam/skin impact,
while a stream of cold cryogen spray is directed at the
same impact point. When the device is properly calibrated, the skin surface is protected from excessive heat, so
there is no blistering or recovery period. If this device is
used to perform test spots around the face before treatment is initiated, the variability of temperature on the
face is impressive.
This procedure is a rather complex and multivariable
equation—one for which researchers are seeking a safe
and effective clinical solution. We believe that a genuine
risk of significant adverse events exists if either the param-
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A
B
C
D
Figure. A and C, Preoperative views of a 62-year-old woman. B and D, Postoperative views after 6 weekly treatments
using positive pressure salt microdermabrasion alone (B) and the identical microdermabrasion treatments followed by
30% glycolic acid/ultrasound treatment (D). Note crow’s feet line improvements.
eters or the technique is not properly selected. Although
we look forward to the publication of controlled studies
and further research for tissue tightening applications, we
believe that all aesthetic surgeons should proceed with
due scientific caution and not prematurely promote this
procedure to the general public.
Ultrasonic Skin Rejuvenation and Intradermal
Drug Delivery
These are two exciting new applications, each of which
involves the use of 3-MHz (or higher) frequencies with
pulsed delivery of relatively low energy. This approach
concentrates energy delivery within the epidermis and
dermis. An ultrasonic wave may temporarily widen the
intracellular spaces of the skin’s outer barrier layer,
known as the stratum corneum. Therefore, the route for
passive diffusion of topically applied agents into the skin
is enhanced. If a second treatment with the ultrasound is
performed—after the topical agent is applied—the agents
can be actively “driven” into the skin with sonic waves.
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The potential for adverse irritation and allergic reaction
is increased when special formulations are not followed;
this is because of the increased penetration of these
agents. The composition of topical agents to be optimized
for this use is significantly different from that of current
skin care product formulations. Our research team has
performed several blinded and controlled studies for
future publication that document this.
Although the application of the proper parameters of
external ultrasound used on normal skin does produce
some benefits, combining this external ultrasound with
prior microdermabrasion significantly improves the clinical result.5 If one envisions the stratum corneum barrier
layer as a brick wall and the ultrasound effect as increasing the space or mortar between the bricks, then a lengthy
“maze” must still be traversed. However, if prior microdermabrasion is used to remove the upper portion of the
brick wall—abrading as deeply as possible while avoiding
pinpoint bleeding—then this may be viewed as a much
more efficient and shorter path for penetration. Because
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topical agents and cosmeceuticals do not polish the skin
surface, the combination of these two modalities is highly
complementary.
In one of our studies, 12 photoaged female patients of
diverse ethnic skin types were treated in a randomized
split-face clinical trial. In this study, the entire face was
treated with positive-pressure salt microdermabrasion,
and one side received an additional treatment of 30%
glycolic acid and external 3-MHz ultrasound pulsed at
25% pulsed duty cycle. Glycolic acid is known to produce increased dermal collagen and glycosaminoglycans
and can thus improve skin elasticity. In this study, skin
elasticity meter data suggested a greater increase in epidermal and dermal elasticity when the combined treatment
was used (Figure). A similarly designed and controlled
study evaluating split faces, in which the entire face was
treated with the same glycolic peel and then one side was
additionally treated only with glycolic acid (no ultrasound), revealed only small differences in elasticity measurements. Both studies are complete, and data analysis is
currently underway. No significant adverse events resulted from any of the treatments.
To avoid possible lidocaine toxicity, which may occur at
unexpectedly low application dosages, precautions
should be taken when this procedure is used to enhance
the effect or penetration of topical lidocaine anesthesia.
In particular, care should be taken when using 1 MHz.
Early controlled studies suggest that externally applied
ultrasound can result in significant clinical skin rejuvenation benefits while maintaining an excellent safety profile—provided that proper parameters are followed and
the correct technique is used. To optimize this new thera-
External Ultrasound: New Clinical Applications
AESTHETIC
peutic option, a new generation of skin rejuvenation
products specially formulated for this new application
are needed, and further studies must be conducted. Used
wisely in combination with our other established aesthetic procedures, external ultrasound may enhance and
extend aesthetic results and can blend or transition the
neck and chest areas after facial aesthetic procedures. ■
I would like to acknowledge John B. Newman, MD, chief
resident in the Department of Surgery, Naval Medical
Center Portsmouth, and a former research fellow, for his
help in the preparation of this article.
Dr. McDaniel is the director of Anti-Aging Research &
Consulting, LLC at the Laser Center of Virginia, and also
serves as Assistant Professor of Clinical Dermatology &
Plastic Surgery at Eastern Virginia Medical School and
Command Consultant in Plastic Surgery at the Naval
Medical Center Portsmouth.
References
1. Rosenberg GJ, Cabrera RC. External ultrasonic lipoplasty: an effective
method of fat removal and skin shrinkage. Plast Reconstr Surg 2000;
105:785-791.
2. Cook WR. Utilizing external ultrasonic energy to improve the results of
tumescent liposculpture. Dermatol Surg 1997;23:1207-1211.
3. Butterwick KJ, Tse Y, Goldman MP. Effect of external ultrasound postliposuction: a side-to-side comparison study. Dermatol Surg 2000;26:
433-435.
4. Kinney BM. Body contouring with external ultrasound. Plastic Surgery
Educational Foundation DATA Committee. Device and Technique
Assessment. Plast Reconstr Surg 1999;103:728-729.
5. McDaniel DH, Newman J. Ultrasound enhanced skin rejuvenation combines modalities. Med Laser Insights 2000;8:2-3.
Reprint orders: Mosby, Inc, 11830 Westline Industrial Drive, St Louis, MO
63146-3318; phone (314) 453-4350; reprint no. 70/1/112063
doi:10.1067/maj.2000.112063
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