The authors are to be commended for their investigation of the next generation of a bi-polar radio frequency device for the improvement of glabellar wrinkles. There are patients that desire correction of forehead furrows but do not want a neurotoxin instilled or developed antibodies. All patinets and clinicians would like a non-surgical or minimally invasive treatment to provide a long-term reduction in glabellar lines. This paper illustrates the possible motor nerve pathways and anticipated deposition of focused ablative, bipolar radiofrequency energy to temporarily block the electrical conduction of specific nerve fibers to muscles that contribute to brow furrows. The dynamic feedback when providing energy via muscle stimulation and an audio signal is helpful to standardize energy delivered and contributes to better treatment consistency. Post treatment pain management was not an issue. Independent review at three months showed nearly an 86% one-point improvement and an 81% 2-point improvement using the visual scale developed by Flynn et al. ¹ Patient satisfaction was also high at three months after treatment. Adverse events were mild and only required over the counter medications.

Percutaneous radiofrequency energy – bi-polar vs. monopolar?

Using a monopolar radio frequency device, Dr. Jun Hyung Kim et al also demonstrated an improvement in glabellar furrows. ² Pain management during treatment was an important component. The majority of patients 93%, received IV sedation using propofol and fentanyl. Two independent evaluators assessed post treatment results for a minimum of 12 months. Study photographs showed impressive improvement at a mean follow up time of 18 months after treatment using a different credible visual analysis scale. ³ Results lasted more than 12 months in 78% of the patients. One patient had a skin burn that resolved with conservative care. Commentary by Dr. David M. Knize ⁴ sheds some light on the acceptability of this radio frequency device – “Clearly, the success of the nerve ablation depends on the surgeon’s skill in maneuvering the probe tip for positioning of the electrode.”

Variables that make treatment predictability claims difficult.

In this multi-center study the authors make reference to “more predictable results” using this current version of the bi-polar device. Patient satisfaction is an important component when considering efficacy but not predictability. Predictability of results is dependent upon many factors including reproducibility of treatment, patient selection and the method of evaluation. In this study, 21% of the patients required a repeat treatment; re-insertion of the probe into one or more sites during the session. This appears to be a high number of patients that needed additional nerve ablation after their initial intervention was considered successful by the skilled investigators. This contributed to a treatment time ranging from 35 minutes to 1 hour and 40 minutes. Was the need for additional probe reinsertions due to treater expertise, impact of local anesthesia, requisite of patient input or combination of these variables? A successful “temporary conduction block” confirmed by the patient’s ability to demonstrate impaired frowning during treatment could be influenced by their state of sedation, local anesthesia injected for pain control and patient tolerance of receiving additional insertions – nerve ablations.

Ideally, to develop reproducibility, a patient under various levels of sedation would not be relied upon to provide the therapeutic endpoint considered trustworthy by the clinician for consistent treatment. Table 1 shows the wide span of nerve lesions delivered ranging from 2-13 for the corner orbital site targeting the temporal facial nerve, to 1-8 for the nasolabial groove insertion site targeting the angular nerve. Optimal treatment requires effective pain control during nerve ablation. This study allowed for a variety of pain management techniques prior to treatment. It is unclear as to which sedation protocol was associated with patients that did not need probe re-insertion or had improvement at 6, 9 and 12 months. Coaching patients to provide maximum brow furrowing to obtain photographic image capture for analysis is unavoidable but impacts current study results. This could be mitigated by an analysis of pre and post treatment muscle function using a dynamic video recording of muscle activity.

Another factor to consider in terms of brow positioning is the role of the orbicularis oculi muscle whose impact varies based on patient age and not targeted in minimally invasive radiofrequency therapy. Using electromyography, these authors demonstrated that the orbicularis oculi muscle recruitment unlike the frontalis and corrugator supercili muscles increased with older patients and contributed to dynamic brow positioning. ⁵ The dynamic impact of the orbicularis oculi may factor into the initial and long-term efficacy in patients treated with radiofrequency energy that solely focuses on the nerves impacting the procerus, depressor supercili and corrugator muscles.

Claims of long-term efficacy and a more natural result vs. neurotoxin have not been confirmed.

One of the purported claims of this study is a sustained benefit. Reference is made to the length of neurotoxin effectiveness as a basis of comparison. The authors state their variable range of long-term efficacy determined by investigator analysis was due to initial patient selection, which required study patients to have moderate to severe glabellar lines. The same impact of long-term effectiveness could be forwarded for study patients that receive a neurotoxin. A “more steady plateau effect” with radiofrequency treatment vs. neurotoxin as the ablative impact resolves is speculation. Providing a more natural result via radiofrequency therapy is conjecture. This study did not evaluate a comparison to a neurotoxin for glabellar furrows. The method of evaluation hinders long-term claims. The visual analysis of standardized photographs by 3 independent reviewers was limited to the 3-month, post treatment period. In contrast, evaluation by the investigators at 3-months showed a slightly higher improvement rate, 92% vs. 85.9%. Subsequent evaluation at 6, 9 and 12 months after treatment was only performed by the investigators. The change in evaluators and method of evaluation impacts the standardization of study results and long-term efficacy claims.

What is the next step?

Going forward the authors are encouraged to continue their research efforts. Currently, the application of this technology is an art form. Initial success is dependent upon multiple treatment components. Some of these variables may be an essential part of this therapy. Validation of subsequent study results regarding long-term efficacy could be improved. Visual analysis by blinded, independent evaluators for the length of the study using standardized pre and post-treatment video recordings would be helpful. Using 3-D image capture technology that utilizes computer algorithms for data analysis vs. a clinician’s interpretation of a visual analysis scale would add credibility to claims based on comparisons of standardized, static photographs. ^6-9 These devices can be rented and data analyzed by a non-study, blinded individual for all sites.¹⁰ Potential adverse effects in patients that receive subsequent radio frequency sessions needs to be addressed. As more patients receive repeated nerve ablation therapy, nerve dyskinesia and other safety issues may surface. A prospective study comparing the effectiveness of this technology vs. a neurotoxin would help substantiate claims made in this paper and add clarity to cost comparisons.

This article has been accepted for publication in Aesthetic Surgery Journal Published by Oxford University Press.

Disclosure – I have no conflict of interest.

Resources

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10. Personal correspondence. Canfield Scientific, Parsippany, NJ.