Commentary on: Bipolar Fractional Radiofrequency Treatment of Suprapatellar Skin Assessment Using Noninvasive Devices and Microbiopsy

Based on this paper, would you feel safe and confident to use a transcutaneous, bipolar radiofrequency device for an off-label location? Would you purchase a transcutaneous, bipolar radiofrequency device to treat suprapatellar skin based on a positive molecular change in the underlying dermis? Most importantly, would you want the ability to consistently reduce undesirable skin wrinkles in the knee region of your patients?

The authors have taken on a difficult task. There have been few peer-reviewed publications on radiofrequency or ablative energy treatment of suprapatellar skin to improve skin wrinkling. The title of this paper does not represent its scope. There are 2 separate issues addressed: the efficacy of the Profound System (Candela Corporation, Wayland, MA), a bipolar radiofrequency device for treating skin wrinkles in the suprapatellar region, an off-label use; and the ability/accuracy of employing multiple noninvasive devices and microbiopsy to confirm wrinkle reduction.¹

On its website Candela describes only facial applications for its system.^2-7 Thus, the challenge for this study was to show efficacy in nonfacial regions. The authors have provided an IRB-approved study for the off-label use of the Profound System device.

In their introduction, the authors state that the skin of the suprapatellar region is similar to the skin of the lower face and neck. Although this may be true histologically, I contend that there is a significant difference in the dynamic, functional impact of repetitive flexion of the suprapatellar skin that makes any skin wrinkle reduction treatment in this region different compared to the face and neck regarding lasting improvement. The authors confirm this in their discussion.¹ Essentially, technology that works on the face and neck may not be efficacious in locations such as the knee or elbow when following facial treatment protocols.

Beyond anatomic location, there may be other issues affecting the results. The methods section does not identify if all patients were treated by a single clinician or report the expertise of the treating clinician with the Profound System device. The stated patient exclusion criteria were, “individuals who had undergone dermatologic procedures for the treatment of wrinkles, skin resurfacing, or skin rejuvenation in the treatment area within 1 year of study participation.” Ideally, study patient exclusion criteria should have included conditions that affect wound healing such as diabetes, patients with an autoimmune disorder, or previous surgical treatment in the knee region, and should have made reference to the physical, occupational, and recreational activity levels of the study subjects. There were not enough patients in the study to segregate patient age as a factor to assess treatment efficacy. All these factors can affect device efficacy.¹

Another concern about the methods centers on the data obtained from the many noninvasive devices utilized. Who operated these devices and what was the expertise of these operators? This paper did not demonstrate any proficiency-reproducibility of data capture by these tools on nonstudy patients by the investigator(s). Such information provides the baseline of evaluator competence/reproducibility when utilizing these devices; essentially, this serves as a “control” group for the use of such technology. The use of several noninvasive devices was described: the AquaFlux AF200-01 (BioX Systems Ltd, London, UK), the VivoSight optical coherence tomography system (Michelson Diagnostics, Maidstone, UK), the DUB SkinScanner75 (taberna pro medicum GmbH, Lüneberg, Germany), and the BTC-2000 (SRLI, Nashville, TN). I doubt that most readers have an understanding of these analytic tools, although the study results are based in part on data acquired with these noninvasive devices.¹ Hence the value of determining the reproducibility of data capture by these noninvasive devices on nonstudy patients by investigator(s) prior to performing the actual study: this approach would have validated the “hands-on” accuracy of the analytic technology used by the investigator(s).

Photographic assessment was also used to access efficacy. There is a lacuna in the description of image capture given in the methods section. The section states, “Standard and close-up photography of the suprapatellar region of both legs were obtained to be used for evaluation of skin texture and laxity.” It is not clear what “standard” photographs represent and whether these are acceptable for longitudinal analysis. Without a described, reproducible method for obtaining photographic images, it is hard to base study results on images. From my experience, underlying muscle contraction, lighting, and patient positioning can affect how static digital images show skin surface contour/texture. The methods section does not delineate how the image capture was performed to confirm reproducibility for longitudinal evaluation. In addition, the picture evaluators were a plastic surgery fellow, a plastic surgery resident, and a medical student.¹ The selection of study picture evaluators ideally would have been off-site, “blinded” clinicians who have expertise with the Profound System device rather than the trio used in the paper.

Providing lasting wrinkle reduction in the knee region is something that all clinicians and patients want regardless of the technology. I encourage the authors to continue their research. Photographs used for analysis should be truly “standardized” and the methodology used to capture them explained to allow for an accurate longitudinal analysis. Multiple noninvasive analytic technologies were used in this study. The skill set of the investigators with such tools should be confirmed in advance.

In future work on the knee region, the authors could consider investigating multiple treatments with the Profound System device at intervals to allow for dermal healing and skin contraction. Future IRB-approved studies could utilize different device energy settings that do not parallel facial treatment energy settings. The authors treated roughly 180 cm² of suprapatellar skin; extending the treated area may give different results.

Disclosures

The author declared no potential conflicts of interest with respect to the research, authorship, and publication of this article.

Funding

The author received no financial support for the research, authorship, and publication of this article.

References

Author notes