Clinical Applications for Ultrasound and Electrical Stimulation in by a76m823ik


									      Clinical Applications for Ultrasound and Electrical
              Stimulation in the Aesthetic Office

  Printed in the Winter 2001 Edition “Specialty Skin Care” Official
   Publication of the Society of Plastic Surgical Skin Care Specialists

Minimally invasive cosmetic procedures, such as microdermabrasion,
application of prescription topicals and non-ablative laser treatments are
gaining in popularity. It seems more and more people are willing to achieve
their cosmetic goal with less traumatic sequential treatments and virtually no
down time. Common clinical goals seem to include collagen stimulation (for
skin texture improvement and the reduction of fine lines), pigment
reduction, and general skin rejuvenation from photoaging. Ultrasound and
electrical stimulation can play a distinct role in the overall treatment of these

Both ultrasound and electrical stimulation are excellent methods of
increasing blood flow and have an extensive history in the treatment of
wounds. Although ultrasound and electrical stimulation accomplish many of
the same things, their mechanics are considerably different. It is imperative
to fully understand their unique characteristics in order to safely utilize them
in cosmetic applications.

Sound waves are mechanical pressure waves that are described in terms of
their frequency. Audible sound has an approximate frequency range of 50 to
20,000 hertz. Ultrasound waves have frequencies greater than 20,000 cycles
per second. Depth of penetration into tissue is determined by the frequency
of the ultrasound. The lower the frequency, the greater the depth of
penetration and the higher the frequency, the less the depth of penetration.
An example of this is how apartment dwellers can hear musical deep bass
notes through their walls and very little of the high frequency sounds. One
MHz (one million hertz) is the most common therapeutic ultrasound
frequency. Physical therapists prefer this frequency because of its depth of
penetration, which is about 3  -5cm. Deeper penetration is required when
treating shoulder and hip joints. Therefore, higher frequencies are more
appropriate on the face because of thinner tissue. 2 MHz penetrates about
15mm. 3 MHz penetrates even less, but stands a greater chance of rapidly
overheating superficial tissues.

When ultrasound enters the body it reacts in various ways--it is absorbed
more readily by muscle, tendons and bone than by fat. Harder surfaces like
bone will absorb and reflect ultrasound energy. All of these factors will play
a role in the eventual total tissue temperature rise. Researchers have found
that by raising the tissue temperature by 10 degrees C, the local metabolic
rate will increase 3 to 4 times. This in turn dramatically increases Oxygen to
the cells and the removal of waste products. Tissue can be heated to
between 40 and 45 C without damage. Using a 2 MHz ultrasound at 1.5
watts per centimeter squared for 5 minutes will raise tissue temperature
about 5 degrees C. Ultrasound intensity and time on tissue determines the
amount of heat generated. Studies have shown that there also non-thermal
benefits from ultrasound. These would be in the range of .5 watts per
centimeter squared or less and or on pulsed.

Known Clinical Uses for Ultrasound Include:

   • Treatment of inflammation and edema reduction: Post trauma, either
     surgical or from a non-ablative laser, causes degrees of inflammation.
     The goal is to reduce this swelling quickly to eliminate any further
     cellular damage. Low intensity ultrasound alters cell permeability and
     aids in the reabsorption of interstitial fluid. Heat generating settings
     should never be used because heat would only exacerbate an already
     swollen situation.
   • Tissue Healing: Ultrasound has been shown to enhance tissue repair
     through increases in macrophages, fibroblasts, endothelial cells and
     collagen. Some feel that these stimulated repair mechanisms are from
     the heat generated by ultrasound, while others feel that the non-
     thermal effects of cellular micromassaging are the cause. The bottom
     line is that ultrasound has been proven to advance the healing process.
     Wounds, of course, represent the extreme; however, stimulating photo
     damaged or sub-optimal aging skin will result in healthier more
     vibrant skin.
   • Phonophoresis: is the use of ultrasound to drive medications or
     topical products into the skin. The American Society for Aesthetic
     Plastic Surgery recently stated: “New skin care product
     formulations, used in conjunction with ultrasound, will allow for

     deeper penetration of topically applied rejuvenating agents into
     the skin, resulting in significantly improved aesthetic results.”
     This is accomplished by the combined mechanical piston like effect of
     ultrasound and the altering of cell permeability. This process does not
     alter the chemical composition of the topical and is pleasant for the
   • Increases extensibility of collagen tissue: Ultrasound used in higher
     intensities coupled with stretching can improve the appearance and
     texture of scars.

Electrical stimulation comes in many waveforms. The waveform described
here is the one most accepted as an optimum stimulating waveform. This
twin peaked, fast rise time, high voltage/micro amperage waveform most
closely mimics the bodies endogenous bioelectric system. This enhancement
of the natural electrical network has been shown to be valuable in a wound
situation or where cells are not performing optimally. The goal with any
form of stimulation is to achieve the proper depth in tissue with no harm to
collateral tissue. This waveform is totally safe and comfortable for the

Known Clinical Benefits of Electrical Stimulation Include:

   • Improves blood flow and wound tensile strength: Improved blood
     flow is extremely important in most tissue related problems, whether
     the problem is an open wound or damaged cells. The mechanism of
     improved blood flow is related to electron flow and mild muscular
   • Stimulates protein and DNA synthesis in human fibroblasts:
     Electrical stimulation has been successfully used to treat decubitus
     ulcers for years. The U.S. Department of Health and Human Services
     stated that electrotherapy was the only adjunctive therapy they
     recommended for treating pressure ulcers. This was after evaluating
     hyperbaric oxygen, low-energy lasers, cytokine growth factors and a
     variety modalities and topicals.
   • Promotes migration of epithelial, fibroblast, neutrophil, and
     macrophage cells: These necessary factors of repair seem to be
     attracted to damaged tissue, and are required to contribute to
     granulation tissue formation and anti-inflammatory activities.

   • Edema reduction: Swelling reduction is important, especially in
     acute trauma. This is the reason that every major sports team uses E-
     Stim to dramatically reduce swelling in acute injuries. This same
     concept may be applied to post laser resurfacing, liposuction, etc.

Contraindications and precautions include not using any form of stimulation
when tumors (either malignant or benign) are present, cardiac pacemakers,
over the eyes and pregnancy. Electrical stimulation may be felt stronger in
sensitive teeth and where Botox injections have been given. With any form
of stimulation, caution should also be used around the carotid area on the

The FDA considers all forms of ultrasound and electrical stimulation to be
class II devices. This means that they may only be sold to and used under
the guidance of a licensed physician. The FDA simply classifies devices
that have the potential to create harm. It remains the responsibility of
licensing boards of individual states to regulate their members.

There are important safety and reproducibility considerations with
ultrasound equipment, just as with lasers or any other medical cosmetic
device. The main goal in cosmetic ultrasound is to properly stimulate tissue
to achieve optimum skin health. Choose an ultrasound with the proper
frequency and safety features for the face. Standard off of the shelf physical
therapy devices with 1 MHz sound heads are too penetrating for cosmetic
work. Accuracy at low and high power is critical because sometimes your
goal will be non-thermal and other times heat generation is required. An
inaccurate device may afford results ranging from no results at all to the
exact opposite of the desired result. An ultrasound that maintains your
setting, regardless of the varying tissue impedances encountered, is ideal.
Another important issue is the equal distribution of ultrasound energy across
the entire surface of the soundhead. If all the energy is being emitted from
the center of the surface there is an extreme high power density, and once
again, you might be damaging cells rather that stimulating them. Think of
the soundhead as an iron. You want a totally uniform delivery of heat. If all
the heat came out of a small portion of the iron your results would be less
than desirable. Ultrasounds are available in stand alone units, as are
electrical stimulators. There are also systems that combine both.

A successful skin care program will incorporate various tools to meet the
patient’s individual needs. Ultrasound and E-Stim offer solid clinical

benefits that are cost effective. These systems not only offer their own
specific benefits, but work adjunctively with lasers and a wide variety of
topical products.

Michael Mosk
Pentech, Inc.


To top