Does Radiofrequency Assistance Improve Skin Contraction after Liposuction?

Sir:

Chia et al¹ conclude that radiofrequency-assisted liposuction provides greater skin contraction of the arms than aggressive superficial liposuction. Unfortunately, no measurement data are presented, only the percentage changes in 10 patients. Two patients underwent skin excisions. The authors do not report the inclusion rate or whether their study was prospective or retrospective.

Area varies as the square of any linear dimension of an equilateral triangle (Fig. 1). If the height decreases approximately 20%,¹ one would expect the surface area to drop 36% [(100 – (80 x 80%)]. Surprisingly, the reported reduction in triangular surface area (8.1%–15.0%¹) is less than the reduction in height—the opposite of what is expected. This discrepancy is impossible to reconcile with basic geometry.

Fig.1.

A 58-year-old woman is seen before (A) and 1 year after (B) ultrasonic liposuction of the arms and axillae using a single axillary incision and superwet infiltration. The liposuction aspirate volume was 125 mL from the left upper arm. An equilateral triangle has been superimposed. Side measurements are shown. The height is depicted as a vertical line from the base of the triangle to its apex. This height measurement is analogous to the point of maximum dependency measurement used by the authors. The authors reported that after surgery the point of maximum dependency decreased approximately 20% (B). For an equilateral triangle, area = (side length)²√3/4. Height = (side length)√3/2, and varies in a squared relationship with area. A 20% decrease in this linear measurement produces a 36% reduction in area (B). Note that these triangles are for illustration purposes only. They do not reflect any real difference in skin landmarks in this patient. The photographs are matched for size and orientation using the Canfield Mirror 7.4.1 imaging software (Canfield Scientific, Fairfield, N.J.).

The authors write, “The procedures were either performed under Institutional Review Board protocol (Essex Inc., Lebanon, N.J.) (sic).”¹ Oddly, this sentence is incomplete. After being repeatedly cited for deficiencies by the U.S. Food and Drug Administration,² Essex dissolved in 2011.³ Hence, it is not clear that proper institutional review board approval and informed patient consent were obtained. BodyTite (Invasix, Yokanem, Israel) is not for sale in the United States and has not been cleared by the U.S. Food and Drug Administration.⁴ Author travel expenses were reimbursed and all patients were Fitzpatrick III to V skin types.¹ Was this study done in Colombia? Photographs include patients who were not in the study. Figure 8 is duplicated from a previous publication.⁵ This patient could not have undergone surgery during the July 2012 to July 2013 study period because she was included in the previous study of patients treated (under local anesthesia) between April 2009 and February 2012.⁵

It is risky to suggest that a larger sample would have demonstrated a significant treatment benefit.¹ Observational error is unavoidable when measuring the sides of small triangles on the skin. Distances are likely to shorten simply as a result of reducing bulk. If the skin is subjected to the same degree of stretch, any perceived contraction might disappear.

Aggressive superficial liposuction is not generally recommended because of an increased risk of complications.⁶ If one side is treated more aggressively and more superficially,¹ the contractility of the skin may be impaired, creating a confounder that undermines the comparison. The average total aspirate volume is reported as 957 mL, and 534 mL per arm.¹ One would expect the mean aspirate volume per arm to be half the total. Using traditional liposuction cannulae, the entire upper arm and axilla can be accessed from a single axillary incision (Fig. 1), avoiding unnecessary scars and minimizing risk to the ulnar nerve. The learning curve clearly favors traditional (not aggressive, superficial) liposuction.

The article does not include a discussion of its limitations, which are remarkably similar to those of another commercially sponsored study⁷ claiming improved skin contraction after ultrasonic liposuction.⁸ Objectivity is sacrificed when the investigators have a financial interest.^8–10 Plastic surgeons must remain diligent to ensure that our publications are based on sound data, and do not become simply marketing tools.¹⁰

DISCLOSURE

The author has no financial interest to declare in relation to the content of this article. The Article Processing Charge was paid for by the author.

Eric Swanson, MD
Swanson Center
Leawood, Kans.