Extracorporeal Shock Wave Treatment for Cellulite

Gynoid lipodystrophy - better known as cellulite - represents the most common lipodystrophic disease and is found in 85% of post-adolescent women. Cellulite usually develops in particular anatomical areas such as the thighs, buttocks, abdomen, and upper arms and becomes visible through its classical 'orange peel' appearance - an irregular, dimpled skin surface with thinning of the epidermis/dermis and the presence of nodular clusters of fat cells. It represents not only a cosmetic concern for women, but often becomes a major psychological problem impairing sports activities, clothing choice, and social interaction.

The pathophysiology of cellulite is related to various predisposing factors such as biotype, heredity, race, body weight, age, hormonal changes, smoking, and genetic predisposition. Four main hypotheses regarding the etiopathogenesis of cellulite have emerged over the last decades: a different anatomical conformation of the subcutaneous tissue in women compared to men, changes of the biomechanical properties of epidermal and dermal tissues, excessive hydrophilia of the extracellular matrix increasing interstitious pressure and causing edema of the fatty tissue, and alterations of both microvascular and lymphatic circulation that result in the often painful protrusion of subcutaneous adipose tissue into the lower reticular dermis, causing the distinctive mattress-like surface irregularities. However, these hypotheses are mutually conflicting and do not consider recent advances in our understanding of the complex physiopathology of the adipose organ. For instance, one cannot exclude that inflammation also contributes to the formation of cellulite.

Nevertheless, various treatments for cellulite have been developed over the last decades, focusing on skin tightening with radiofrequency or lasers, improving blood and lymphatic circulation using both physical treatments and pharmacotherapy, and treating deeper deformities with surgical subcision, laser treatments, ultrasound devices, or liposuction. However, there is no single treatment of cellulite that is completely effective.

In recent years, extracorporeal shock wave therapy (ESWT) and radial shock wave therapy (RSWT) have been introduced as safe and effective treatment options for cellulite. A shock wave is an acoustic pressure wave that is produced in any elastic medium such as air, water, or even a solid substance. Shock waves differ from sound waves in that the wave front, where compression takes place, is a region of sudden change in stress and density. Therapeutic shock waves are characterized by a high positive peak pressure (usually between 10 and 100 MPa), a fast initial rise in pressure (less than 1 µs), a diffraction-induced tensile wave (up to -10 MPa) following the positive pressure amplitude, and a short life cycle of approximately 10-20 µs. Extracorporeal shock wave lithotripsy (ESWL) is widely used for stone management in urology. ESWT and RSWT are byproducts of lithotriptor technology. Since the late 1980's they have been introduced into the treatment for various diseases of the musculoskeletal system such as plantar fasciopathy, Achilles tendinopathy, medial tibial stress syndrome, greater trochanteric pain syndrome, lateral and medial epicondylitis, and calcifying tendonitis of the shoulder. Shock waves have both a direct and indirect effect on treated tissues. The direct effect is the result of the energy of the shock wave being transferred to the targeted tissues. The indirect effect is the result of the creation of cavitation bubbles in the treated tissue. It has been hypothesized that both the direct and indirect effects produce a biological response in the treated tissues. ESWT devices share two technical key characteristics of ESWL devices used for stone management, namely the electrohydraulic, electromagnetic, or piezoelectric generation of pressure waves and the generation of focused or so-called defocused pressure waves. Radial shock waves are generated ballistically, i.e., by accelerating a bullet that strikes an applicator, transforming the kinetic energy of the bullet into a radially expanding pressure wave.

Unaddressed in the studies on ESWT/RSWT for cellulite carried out to date is whether the individual clinical outcome of the therapy can be predicted by means of the patient's cellulite grade at baseline, age, body mass index (BMI), weight, height, and/or age. This was addressed in the present study using RSWT. We hypothesized that the individual clinical outcome of RSWT for cellulite can be predicted by means of the patient's cellulite grade at baseline and the patient's BMI.