Skin Tightening: Fact or Fiction?
Where does the term skin tightening come from? Is it a physical terminology for properties of the skin or is it in relation to the appearance of the skin (skin’s optical reflectance)? Fundamentally the answer is both. As you change the physical properties of the skin you must also change the way the skin reflects light, which then alters what is perceived by the human eye. So according to this there is no debate that if we change the properties of the skin, we can make the skin “look” tighter. The real question then is how and what properties of the skin quality need to change to give it the appearance of being tighter? Starting here, we can look at the current methods used to claim “Skin tightening”, in an effort to demystify this all-encompassing consumer friendly expression.
So let us start with the basics. Few would argue that a face-lift performed by an accredited surgeon does not cause skin tightening. The question then is not that a face-lift causes skin tightening but rather it is what has changed in the properties of the skin in order to achieve this “tighter skin” result.
Unfortunately there is no winch or pulley behind our ear which we can just turn to increase the tension in our skin. In actual fact there is not any current, reliable way to increase the tension in a person’s skin at all, but we will address that later. So let us instead look at what we can do surgically for sagging skin.
Step 1 - Tightening the SMAS (A thin connective structure overlying the facial muscles) by folding it on top of itself or by excising the desired amount.
Step 2 - Re-drape the skin over the newly “tightened” facial structure.
Step 3 - Remove the excess skin
* Note - This is an example of a SMAS plication/excision surgical technique. It is by no mean the way all facelift surgical procedures are performed. As with any surgical techniques, operative procedures must be tailored for each individual patient.
Now for the big question. In any of these steps above did we tighten the skin? No, we actually removed it, and usually quite a significant amount of it. So lets move on, to another way to remove skin that has been associated with skin tightening; traditional laser resurfacing.
This is where things start to get a little tricky, and just a little bit controversial. Yes laser resurfacing removes skin, but is it the removal of this skin that causes the skin to be tighter? Possibly, but to understand, as with any energy based procedure, what is the most plausible mechanism of action for the appearance of tightened skin, we again must break it down into steps.
Step 1 – Evaporate the whole upper layer of the skin. As far as volume of tissue removed is concerned this is miniscule. Even in the traditional resurfacing sense, the couple of hundred microns of tissue removed from the face, pails in comparison to what can be removed surgically. Below is an example on how massive the gap is:
Assume a face is roughly 370sqcm in area, and another ½ a cm in depth. This gives us 185cm3 in facial skin volume. Now lets assume that when we do a facelift we remove above 1.25cm by 5cm or ½ inch by and 2 inch’s away from each preauricular area affecting the lower part of the face (92.5cm2 volume). This would give us a total volume of removed tissue of 6.25cm3, or roughly 6.75% of removed skin volume in the lower face.
Now let us do the calculation for the laser resurfacing.
With the whole lower face being resurfaced (non fractional) at the most aggressive ablative depth of 200microns(.02cm) we have a removed a volume of 3.7cm3 or ~2%
Even in this example the difference is massive – A more than 3x factor of difference in tissue volume.
Step 2 - This is a much larger variable as it very strongly correlates to the physician and their device determining the amount of tissue change. In this step we look at the amount of coagulated (irreversibly) damaged tissue in the resurfacing process. Since this tissue is not removed, and we have never seen histology of this tissue staying in it’s shrunken state of a healed deep partial thickness burn,we will assume that this is not physically tightened tissue. It is tissue, however, that will be built upon and remodeled as nearly all histology samples of partially denatured collagen at 3,6, 9 and even 12mths post procedures show. It is important to note, just because coagulated tissue doesn’t stay that way it doesn’t mean that it cannot be responsible for the appearance of tighter skin. On the contrary, this remodeling process it seems is imperative, in conjunction with the minimal tissue removed, in providing the best examples of the appearance of tighter more youthful skin of any of the non-surgical energy based devices to date.
Now since most of traditional resurfacing today has been replaced by fractional methods, most people might argue that it is more important to address how fractional resurfacing tightens skin.
Thankfully, the fractional method of skin resurfacing is literally a mathematical modification of the traditional technique, albeit changing two of the axes’. Instead of removing more of the tissue area (the x and y axis), it uses depth (z axis) of injury to balance the amount of total tissue volume removed. In the best-case scenario, this means that ablative fractional resurfacing could remove up to the same amount of tissue volume, as it’s traditional resurfacing volume, not more.
So here we have three examples of skin appearing to be tighter but not actually being tightened, which is not a bad thing. In the end, that is exactly what we want “the appearance” of tighter skin, not the literal interpretation of the expression.
There is however one area we did not touch on that may also hold they key to demystifying non-surgical skin tightening. Skin Elasticity - improving the skins elastic recoil and therefore its resistance to gravity.
Will our newfound love for elastin help unlock the mysteries of skin tightening? Only time will tell...
Laser Resurfacing 101
What is laser resurfacing? The simplest explanation is that it is the use of a laser to remove a portion of the outer layers of the skin. If 100% of the skin surface area is removed we call it full field resurfacing. If a portion of the outer layer is removed leaving some portion untreated it is called fractional resurfacing. It all started in the mid 1990’s with the introduction of the carbon dioxide laser which has a wavelength of 10,600nm and an absorbing chromophore of water and is used to vaporize tissue. Carbon dioxide resurfacing became very popular and replaced chemical peels and dermabrasion in many practices. There were many devices from different manufacturers which caused some tissue ablation and left some residual thermal damage. These were full field devices that most of the time were used to take off 100% of the epidermis and some of the dermis. The energy used and the number of passes controlled the depth of treatment. Short term results were often fantastic with wrinkle eradication and tissue tightening. Unfortunately, longer term studies showed hypopigmentation in a large percentage of patients. These pigmentary complications and the considerable downtime created for the patient led to the demise of “full field” carbon dioxide laser resurfacing around the turn of the century.
Erbium:YAG lasers (2940nm) were introduced around 2000 and have a higher water absorption coefficient than carbon dioxide lasers (about 10 times more efficient). This means that they ablate tissue with much less thermal damage (5-10 microns). Complications were fewer yet downtime appeared to be similar to carbon dioxide systems. Combination systems of carbon dioxide and erbium lasers were popular for a short time (Derma-K, Lumenis lasers, Yokneam, Israel). Variable or long pulse erbium lasers (Sciton Inc, Palo Alto, CA) allow variation of pulse width allowing control over the amount of residual thermal injury produced for a given amount of tissue removal. These variable pulse Erbium:YAG systems produce skin tightening and wrinkle reduction similar to carbon dioxide lasers with a much shorter period of erythema and much lower risk of hypopigmentation.
Other wavelengths for skin resurfacing have been introduced (2780nm and 2790nm) (Cutera Lasers, Palomar Lasers) which allow variable degrees of thermal damage and ablation settings but with limited commercial success.
In 2004 Manstein et al introduced the concept of fractional photothermolysis. These lasers resurfacing treat a small ‘fraction’ of the skin at each session, leaving skip areas between each exposed area. This was first performed using non-ablative fluences at 1550 nm (Reliant technologies Mountain View, CA – now Solta Medical). These non-ablative fractional lasers created a column of thermal damage with intact epidermis. Healing occurred from deeper structures as well as from adjacent structures. Advantages include avoidance of an open wound and very low risk of pigment disturbance or scarring. Disadvantages include the need for multiple treatments and somewhat less clinical response than with full field ablative resurfacing. There are now many manufacturers with similar non-ablative fractional devices with wavelengths of 1440nm 1540nm and 1550nm.
Fractional ablative resurfacing with carbon dioxide, erbium, and YSGG systems were then introduced which ablate a channel into the skin. These devices differ not only in wavelength but in system power, spot size and amount of thermal damage created adjacent to and deep to the ablated hole. As with the non-ablative fractional systems direct comparisons between devices are difficult as devices differ in power output, spot size, density and degree of thermal damage but similar degrees of injury should produce similar clinical results.
The newest wavelength to be introduced into the fractional arena is the Thullium (1927nm) by Solta Medical. This non-ablative fractional device is especially effective in removing superficial pigment.
Full field ablative resurfacing and both fractional ablative and non-ablative systems remain very popular in clinical use at this time.
Dr. Jason Pozner
Unwanted Armpit Sweating: Treatment with the miraDry Microwave Device
Axillary (armpit) hyperhidrosis is thought by many to be an under reported problem with few treatment options. In a 2002 survey, 2.8% of individuals were thought to have excessive or abnormal sweating with 1.4% feeling that the problem was concentrated in their armpits. In another 2008 online survey, 33% of adults felt they had excessive underarm sweating, but only 5% sought any form of help. In another survey conducted in 2009, 4% of US adults were diagnosed by a physician to have hyperhidrosis. Another 17% were bothered by their amount of non-exercise induced sweating. Of note, the impact that excessive sweating has on the quality of life is thought to be similar to that of both psoriasis and acne. The Dermatology Life Quality Index (DLQI) mean baseline score for axillary hyperhidrosis is 10.45, whereas the DLQI doe psoriasis is 10.53 and the DLQI for acne is 7.45.
There are few treatment options for axillary hyperhidrosis. Antiperspirants can do only so much; many patients do not want botulinum toxin injections for this purpose. A new procedure based on microwave technology (miraDry) was FDA approved for the treatment of primary axillary hyperhidrosis in January 2011. It has now just become commercially available. The technique uses microwave energy and results in thermal damage of the sweat glands. This microwave energy is part of the electromagnetic spectrum lying somewhere between radiofrequency and laser energy.
The miraDry technology focuses energy delivery to the dermal-fat interface. The energy becomes concentrated along this interface and creates a focal energy zone. This heat zone is concentrated at the level of the sweat glands. The overlying epidermis is not affected because of continuous surface cooling that prevents backward thermal conduction of heat.
In a study presented at the 2011 American Society for Lasers in Medicine and Surgery meeting, data from a 7 site study was presented. In the study, entitled DRIUP (Dermatologic Reduction in Underarm Perspiration), 120 subjects were treated. 2/3 of the subjects were treated with a prototype of the current miraDry device while 1/3 was treated with a sham control device. A 6 month follow-up of sham treated subjects was undertaken while a 12 month follow-up was undertaken for those treated with the active microwave device. Two different analyses were undertaken. The first looked at the Hyperhidrosis Disease Severity Scale (HDSS) while the 2nd evaluated the actual weight of sweat emitted after treatment.
In the study, almost 2/3 of treated individuals were women and a little more than 1/3 were male; 85% were Caucasian. In those treated with the miraDry technology a significant decrease in the HDSS was noted with the greatest results seen at 6 months. The gravimetric weight of sweat also decreased more than 50% with the greatest results once again seen at 6 months. Of note, some improvement was still noted at 12 months. Adverse events were quite mild and usually consisted of reports of transient altered armpit sensation. All adverse events resolved over time. No treated subjects felt the adverse events impacted on their daily activities.
MiraDry microwave treatment represents an exciting new approach to the treatment of unwanted armpit sweating.