Commentary

As physicians, we are constantly inundated with calls and inquiries about laser lypolysis, which, like most laser procedures, is surrounded by “hype,” despite the fact that there is little objective, scientific support for its use. I therefore believe that the article by DiBernardo and Reyes is an important addition to the literature on this topic because it begins to scientifically evaluate some of the anecdotal claims that have been made about laser lipolysis.

It has been some time since a procedure has elicited as much discussion and debate as laser lipolysis. Over time, laser lipolysis devices have transitioned away from being used primarily for fat removal. In fact, most companies are now promoting these devices for skin tightening rather than lipolytic purposes—and for good reason. Most of the wavelengths used for laser lipolysis are targeting water. Intuitively, this does not add up. Adipocytes are composed primarily of triglycerides and some cholesterol esters. The water content of a fat cell has been poorly researched. In one study performed in a rat model, water within fat was found to contribute less than 23% of the total tissue water.1 In essence, this means that water may not be the ideal target for laser lipolysis. The inefficiency of these wavelengths for lipolysis results from difficulty moving through the tissues, which has led to manufacturers and practitioners making the two following changes:

DiBernardo and Reyes confirm this, concluding that “the unique quality of adding a laser to lipolysis procedure is its effect on the subdermal connective tissue structure.” There are some devices that are available for treatment in the 900-nm range, which may be more efficient at liquefying or disrupting fat.

This principle is vaguely familiar from ultrasound-assisted lipoplasty (UAL), which was introduced in the United States more than a decade ago.2, 3, 4, 5, 6 As we began to learn about UAL, we heard proponents tout its wonderful ability to tighten the skin. This led to a focus of ultrasound energy on the subdermis as the key component of the procedure. As we all recall, patients would either have tremendous skin tightening or an equally impressive skin injury. The margin for error when heating the subdermis seems precarious at best and the problems associated with UAL occur even in the most skilled of hands. What is most troubling about this promotion of laser lipolysis as a skin tightening device is that these devices are being used not only by surgeons, but also by others with no surgical background or experience in liposuction.

The endpoint of laser lipolysis, in this study, was a surface temperature of 40°C to 42°C. This is cause for additional concern. I am not sure that we all have the luxury of a handheld skin temperature device. As DiBernardo and Reyes state, the temperature at the treatment site is 5° higher than the surface temperature and will tend to increase as heat rises. If we wait until the epidermal temperature is 40°C to 42°C and allow for the heat to rise, this will ultimately result in an even higher temperature. In inexperienced hands, the patient may be susceptible to further injury.

What about the results? A preliminary study by DiBernardo and Reyes prospectively evaluated the skin tightening results of laser lypolysis in five patients undergoing contouring of the anterior abdomen. The patients were evaluated objectively via digital photography and measurement of skin elasticity along with thorough subjective assessments by both the patient and physician. The study reports an average of 22% skin shrinkage after one month and a 17% reduction at three months when compared to baseline. The skin tightening index was also found to be significantly higher than that at baseline, with an average of 26% at three months. The physician evaluated the overall reduction of adiposity as “good” and skin firmness as “excellent” in 80% of the patients. The subjects graded their skin tightening as “fair” at one month and “good” at three months.

While these data points may be promising, there are a few problems with this study, some of which have been recognized by the author. Most obvious is the fact that this study compared the laser treatment sites to baseline measurements rather than comparing them to standard liposuction. We therefore do not know how much skin tightening these patients would have experienced with traditional techniques alone; it remains unknown whether there is in fact a benefit using laser technology for skin tightening.

Furthermore, the authors noted that three out of the five patients lost an average weight of 4 lb, meaning that 60% of the patients had volume loss and possibly would have had subsequent skin tightening from weight loss alone.

Finally, I was intrigued by the authors' evaluation of the skin tightening index. They used an elasticity device that measured changes in movement in response to a vacuum pump and measured the pressure required to lift the skin to specific points. The stiffness of the skin was correlated to skin elasticity. We are left with the assumption that this increase in stiffness is directly related to a change in the elastic properties of the skin caused by the laser. However, it is worth noting that if the patient experienced “scarring” along the subdermal plane, this would have had an effect on the measurement, so the noted changes do not necessarily translate into an increase in elasticity. The true source of the results could be seen in a histologic evaluation, but the focus of the histologic examination in this study was the fat, not the dermis. In short, while the preliminary data are encouraging, a larger study is necessary to draw meaningful conclusions.

We congratulate the authors (and the manufacturer) for introducing scientific inquiry into a field desperately in need of it. In the future, we would hope that the manufacturers of new technology will investigate their claims before promoting their products to physicians and the general public. We also look forward to further investigation by DiBernardo et al.