Objective measurements taken from standardized photographs. M indicates distance from medial canthus to brow; P, distance from midpupil to brow; and I, distance between medial brows.
Photographs taken before (top) and after (bottom) treatment with botulinum toxin type A (Botox, Allergan, Irvine, Calif), showing a patient judged to have a raise in her medial brows.
Photographs taken before (top) and after (bottom) treatment with botulinum toxin type A (Botox, Allergan, Irvine, Calif), demonstrating higher medial brow position after the injections.
Photographs taken before (top) and after (bottom) treatment with botulinum toxin type A (Botox, Allergan, Irvine, Calif), demonstrating an improvement in frown lines but no change in brow height.
Andrew S. Frankel, Frank M. Kamer. Chemical Browlift. Arch Otolaryngol Head Neck Surg. 1998;124(3):321–323. doi:10.1001/archotol.124.3.321
To determine if the medial brow can be elevated following administration of botulinum toxin type A (Botox, Allergan, Irvine, Calif).
A before-after interventional study comparing pretreatment and posttreatment brow height. Objective measurements and subjective comparisons of pretreatment and posttreatment slides were made by 7 independent observers unaware of treatment status. All measurements and observations were based on standardized photographs taken with identical lens settings.
Private facial plastic surgery practice. All injections were performed in office examination rooms without anesthesia or sedation.
Thirty adult patients electively seeking improvement of glabellar frown lines or low-positioned medial brows (angry appearance).
Twenty units of botulinum toxin type A was injected into the corrugator supercilli and procerus muscles. An electromyographic needle was used for the initial 10 injections, and a 30-gauge needle was used for the remainder.
In the objective arm, change in brow height was measured from the medial canthus and midpupil directly vertical to the brow hairs; the change in interbrow distance was also measured. In the subjective arm, the number of patients who were found to have an elevated medial brow by the independent observers was noted. Objective and subjective findings were correlated.
Objective measurements yielded a raise in the medial brow in 8 (32%) of 25 patients from the medial canthus and in 12 (48%) of 25 from the midpupil and an increase in interbrow distance in 17 (59%) of 29 patients. Subjective comparison found 18 (62%) of the 29 patients to have higher medial brows after treatment.
Botulinum toxin type A treatment can create a chemical browlift. Further studies with more specific selection criteria are needed to better evaluate this effect.
THE USE of botulinum toxin type A (Botox, Allergan, Irvine, Calif) for treating hyperfunctional lines and wrinkles has been well-described, and the toxin is rapidly establishing its place in the practice of cosmetic surgery.1- 6 By blocking the release of acetylcholine at the neuromuscular junction, botulinum toxin type A temporarily paralyzes the affected muscles and as a result, the lines in the skin formed by the continuous activity of these muscles tend to smooth out in time.1,2,7,8 During use for treating glabellar frown lines, it became apparent that many patients were experiencing elevation of their medial brows. To explain this phenomenon, it was proposed that the botulinum treatment had selectively paralyzed the muscles that depress the brows and resulted in unopposed action of the frontalis fibers that raise them. The overall effect of this shift in the equilibrium led to brow elevation. With some anecdotal evidence and a working hypothesis in hand, we undertook to determine if botulinum toxin type A is capable of creating a medial browlift.
Thirty patients were entered into this study. All patients were seeking elective improvement of glabellar frown lines or low-lying medial brows, which gave them an angry appearance. Standardized photographs were taken of each patient in full repose before treatment. Each patient underwent injection of a total of 20 units of botulinum toxin type A to the glabellar region. The injection technique involved having the patients frown and relax repetitively to treat only those muscles directly responsible for pulling the brows downward or causing the furrows. In an attempt to be as specific as possible, the first 10 injections were performed with an electromyographic needle. After noting no discernible advantage to using this needle, it was abandoned in favor of a 30-gauge needle for the remainder of the injections. Posttreatment instructions were given to each patient. Each patient underwent evaluation after 2 weeks to ensure that the injection had worked, and photographs were taken in the same manner as were the pretreatment photographs.
Our study was designed to compare pretreatment and posttreatment brow position by examiners who were unaware as possible of the treatment status of the patients. Objective and subjective mechanisms of comparison were used. The objective comparison consisted of taking several measurements from the photographs, including the distance from the medial canthus directly vertical to the inferiormost brow hair, from the midpupil in a direct vertical line to the brow hair, and between the left and right medial brows (interbrow distance) (Figure 1). These measurements were taken without knowledge of whether the photograph was obtained before or after treatment. The subjective comparison involved pretreatment and posttreatment slides examined by a group of 4 facial plastic surgeons, 1 general plastic surgeon, 1 dermatologist, and 1 registered nurse. Each examiner was asked to record whether 1 photograph subjectively demonstrated a higher medial brow or more open interbrow appearance. If no demonstrable difference was appreciated, then it was recorded as such. Examiners were specifically asked to refrain from any observation of frown lines, as this was not the end point for this study. Results of the evaluations were tabulated to determine if a majority or unanimous opinion existed regarding each particular patient.
One patient was excluded from any analysis because of poor photographic standardization. Of the 29 remaining patients, 25 were women and 4 were men. Ages ranged from 32 to 62 years. Occasionally, it was not possible to make accurate measurements because of inadequate brow hair or ill-defined points of reference. In these cases, the measurements were not included in the results. At the medial canthus, measurements in 8 (32%) of 25 patients showed an elevated brow; in 15 (60%) of 25, no change; and in 2 (8%) of 25, a drop in height. From the midpupil, measurements in 12 (48%) of 25 patients showed an elevation; in 10 (40%) of 25, no change; and in 3 (12%) of 25, a drop in brow height. Measurements of the interbrow distance showed an increase in 17 (59%) of 29 patients, no change in 11 (38%) of 29, and a decrease in 1 (3%) of 29 . For those patients whose brow measurements showed elevation, the mean increases in height were 10% and 14% of the initial distances from the medial canthus and midpupil to inferior brow hairs, respectively. The subjective examiners found 18 (62%) of 29 patients to have a more open or higher medial brow after treatment. Ten (34%) of 29 patients were thought to be unchanged, and 1 (3%) of 29 patients was thought to have lower brows. The number of patients determined to have higher brows by any particular examiner ranged from 36% to 79%, and 8 (28%) of the 29 patients were determined to have higher brows by all examiners. Twelve (71%) of the 17 patients whose posttreatment interbrow distance measurements were higher were also subjectively found to have higher brows by most examiners. Ten (83%) of 12 and 7 (88%) of 8 patients whose brow measurements were higher at the midpupil and medial canthus, respectively, were also deemed to have higher brows by the examiners. Of the 15 patients subjectively judged to have a higher brow after treatment, 10 (67%) had higher measurements at the midpupil and 7 (47%), at the medial canthus. Twelve (67%) of 18 patients were judged to have larger interbrow distances.
Although the primary aesthetic use of botulinum toxin type A has been for minimizing various lines and wrinkles caused by underlying muscles, its unique mechanism of action may lead to alternative applications. The eyebrow is a dynamic structure whose shape and height depend on the interaction of specific muscles. The relevant muscles include the frontalis muscle, which elevates the brows, and the procerus, corrugator, orbicularis oculi, and depressor supercilli muscles, which depress the brows. The depressor supercilli muscle has been described as part of the corrugator or orbicularis oculi or as a distinct entity. A recent report by Daniel and Landon9 found the depressor supercilli muscle to be a distinct entity whose disruption led to marked elevation in the medial brow. The vertical fibers of the depressor supercilli muscle originate from the nasal process of the frontal bone and insert into the skin beneath the medial head of the eyebrow.
Although the patients in our study were being treated primarily for their frown lines and not necessarily to raise their brows, 62% did have elevation of their medial brow, creating a more open and relaxed appearance in this area (Figure 2, Figure 3, and Figure 4). We hypothesized that botulinum toxin type A selectively dennervates the muscles that depress the brows and the unopposed action of the frontalis muscle, resulting in slight elevation. To explain those patients whose medial brows were found to be lower after treatment, we suspected that some frontalis fibers were inadvertently affected, allowing for some unopposed depressor activity or passive downward movement of the brows.
We attempted to minimize error by including direct measurements and subjective comparisons and by using evaluators who were unaware of treatment status when feasible. We accept, however, that any study that attempts to measure brow height contains inherent sources of error, because photographs represent only a moment in time, and patients may be caught in various phases of frowning and relaxation. Also, despite the evaluators being unaware of whether the photographs were taken before or after treatment, they still could notice the effect of the botulinum treatment on the frown lines if they focused on this, which perhaps marred the results. Although these potential sources of error undoubtedly exist, the results nevertheless did show a correlation between objective measurement of a raise in brow height and subjective impression of a browlift. The interbrow distance was the most sensitive predictor of a subjective increase in brow height, and increased height at the medial canthus was the most specific determinant.
Although our findings do not guarantee that treatment with botulinum toxin type A will elevate the brow in any particular patient, they do allow for the possibility of it in more than half of those treated and perhaps even more if the injection technique were to be specific for elevating the brows. It is understood that an elevation of the medial brow is not always aesthetically pleasing; however, it may be desirable in patients bothered by an angry appearance or low medial brow and who do not want or cannot afford a forehead lift. It may also be instrumental in allowing patients to predict what they would look like after a browlift. Botulinum toxin type A has been proven to be very safe; it is relatively inexpensive; and its effects are only temporary, making it a very attractive option for certain patients. A more thorough investigation is needed to elucidate specific indications and precise techniques for applying botulinum toxin type A to achieve a chemical browlift and to better evaluate its effectiveness for improving overall facial aesthetics.
Accepted for publication December 10, 1997.
Presented at the autumn meeting of the Academy of Facial Plastic and Reconstructive Surgery, San Francisco, Calif, September 4, 1997.
Reprints: Andrew S. Frankel, MD, Lasky Clinic, 201 S Lasky Dr, Beverly Hills, CA 90212.