Association of Corrugator Supercilii and Procerus Myectomy With Endoscopic Browlift Outcomes

This cohort study evaluates the association of corrugator supercilii and procerus myectomy with endoscopic browlift procedure outcomes.

Key Points

Question

Is the addition of corrugator and procerus myectomy to browlift procedures associated with improved outcomes?

Findings

In this comparative cohort study of 23 patients who underwent browlift surgery with or without corrugator and procerus myectomy, the browlifts with muscle resection were associated with superior glabellar wrinkle reduction compared with the browlifts without muscle resection.

Meaning

In browlift procedures, the incorporation of corrugator and procerus myectomy may result in improved aesthetic outcomes in the glabellar region.

Abstract

Importance

Glabellar wrinkling is a critical component of upper facial aging.

Objective

To compare the long-term outcomes on the wrinkle lines of the glabella and forehead following browlifts with vs without corrugator and procerus muscle resection.

Design, Setting, and Participants

A prospective cohort comparative trial was conducted of 23 patients who underwent browlift procedures by a single surgeon at a single institution (16 with glabellar muscle resection and 7 without muscle resection) between May 1, 2016, and July 1, 2017. All analysis took place between May 1, 2016, and May 14, 2018. The mean follow-up period was 16 months (range, 12-21 months). Sixteen of the 23 patients underwent a browlift with muscle resection procedure alone or in combination with other facial rejuvenation procedures to the brow, midface, jowl, and neck. Four of the 23 patients underwent browlifts only, and 19 had browlifts with other procedures. Seven of the 23 patients had browlift procedures without muscle resection and were designated as controls.

Interventions

Endoscopic browlift surgery was performed either with procerus and corrugator muscle resection or without muscle resection.

Main Outcomes and Measures

Neutral gaze and dynamic photographs of the upper face obtained preoperatively and after the 1-year postoperative mark were reviewed and scored in a blinded fashion by 2 physicians not affiliated with the study team using a modified Fitzpatrick Wrinkle Assessment score (FWA; from 0 [no wrinkling] to 5 [deep wrinkling with redundant skin]).

Results

The 23 study patients had a mean age of 60 years (range, 48-74 years); 21 were women, and 2 were men. There was a significant difference between the myectomy and control groups in the 12-month postoperative improvement in dynamic glabellar FWA scores (2.56 vs 1.07, P = .01). There was a difference between the myectomy and control groups in the improvements in resting glabellar FWA scores at 12-month follow-up, but it did not reach statistical significance (1.28 vs 1.00, P = .38). The 12-month postoperative improvements in dynamic (1.19 vs 1.29, P = .86) and resting forehead (1.0 vs 1.1, P = .70) FWA scores were not significantly different.

Conclusions and Relevance

In this study, the use of procerus and corrugator myectomy techniques appeared to achieve a superior long-term reduction in glabellar wrinkles vs forehead rejuvenation techniques without muscle resection.

Level of Evidence

3.

Introduction

Aesthetic surgery of the aging forehead has been evolving since the earliest descriptions of browlift surgery by Passot in 1919.¹ The traditional coronal technique, often considered the gold standard, has drawbacks such as long scars, scalp numbness, hairline elevation, and alopecia. Several browlift techniques have been developed to address these widely perceived limitations. Many surgeons now support an endoscopic approach, including subperiosteal and subfascial dissections.² Others have promoted an open pretrichial or trichophytic via a subperiosteal approach.³ In addition to elevation of the forehead soft tissues, Hunt in 1926 and Passot in 1930 performed excisions on the glabellar region and above the eyebrows to manage the glabellar creases and to elevate the eyebrows, specifically the procerus and corrugator muscles.⁴ Ever since more recent techniques of ablation of the procerus and corrugator muscles were described in 1992 by Liang and Narayanan,⁵ much debate has ensued over the benefits of this technique. Many support this maneuver only anecdotally, noting a more natural refinement of the glabellar wrinkle lines. Critics portray this as a pyrrhic victory, gained at too great a cost in the form of prolonged convalescence and potential nerve injury. Still others question altogether the longevity of glabellar improvement.

Questions about the benefits of glabellar muscle resection are not new, yet there has been a scarcity of objective evidence to corroborate or refute these judgments. This may relate to the inadequacies inherent in judging browlift results. Short of unwieldy 3-dimensional imaging systems, no practice-friendly device or method exists for reproducibly measuring real changes in forehead rejuvenation, although promising personal computer–based applications are on the horizon.⁶ While commendable, recent comparisons of browlift techniques have largely relied on subjective evaluation or on photographic criteria.^7,8,9,10 In 2 studies specifically investigating the outcomes of procerus and corrugator muscle resection in browlift surgery,^11,12 both of the evaluations relied on retrospective results over several decades without control groups. To our knowledge, there have been no high-quality, prospective, blinded studies investigating the outcomes of procerus and corrugator muscle resection. This lack of definitive evidence allows critics to claim that resection of the corrugator and procerus muscles accomplishes nothing more than to increase operating time, complication risk, and surgeon apprehension.

This stands in stark contrast to the experiential account of those who routinely use the glabellar myectomy in browlift, which is translatable into measurable advantages for the patient and the practice. The senior author (D.A.S.) has over 20 years of results that demonstrate the sustained outcomes of procerus and corrugator muscle removal on the glabella. However, the question remains as to what the glabellar myectomy achieves, and how the change (if any) can be measured.

We sought to submit prevailing browlift techniques to objective intraoperative testing using well-accepted anthropometric measurement tools. To eliminate confounding variables, we standardized the browlift approaches so that the presence or absence of glabellar myectomy maneuver remained the only dependent variable. Our results suggest some important conclusions regarding the merits of the technique used.

Methods

All patients electing to undergo an endoscopic browlift from a single surgeon (D.A.S.) from May 1, 2016, to July 1, 2017, were eligible for inclusion in the study. One patient was excluded because of failure to follow up. Twenty-three consecutive patients who agreed to participate in the study were included, with a mean age of 60 years (age range, 48-74 years). There were 21 women and 2 men. The study was approved by the University at Buffalo institutional review board, and all patients provided their written informed consent to participate. All 23 of the procedures were primary browlifts, and none of the procedures were secondary browlifts. Concurrent procedures included 1 lower and 11 upper blepharoplasties, 9 rhytidectomies, and 4 perioral dermabrasion procedures.

The patients were enrolled to receive either a browlift with muscle resection or a browlift without muscle resection, while all other lift variables were held constant. Photographs were taken preoperatively, and again at 3 months, 6 months, and 12 months postoperatively. The patients posed with neutral expression, with dynamic brow furrowing to demonstrate glabellar muscle action, and with brow elevation to demonstrate frontalis action. A clinically validated wrinkle assessment tool was used, the modified Fitzpatrick Wrinkle Assessment score (FWA) to evaluate the depths of facial wrinkling, with 0 indicating no wrinkling; 1, almost imperceptible wrinkling; 2, mild wrinkling; 3, moderate wrinkling; 4, severe wrinkling; and 5, severe wrinkling with redundant tissue (Figure 1).¹³ The patients were all evaluated by 2 blinded otorhinolaryngology surgeons not affiliated with the study group. Additionally, a postoperative questionnaire was administered to all patients at 3 months, 6 months, and 12 months postoperatively. The questionnaire inquired about the severity of factors such as pain, numbness, muscles weakness, and satisfaction with their results.

Figure 1. Photographic Illustration of the Modified Wrinkle Assessment Scale.

Arrowheads point to the particular area of assessment.

Postoperative patient satisfaction surveys were dispensed to the patients during their routine follow-up, inquiring about their levels of muscle weakness, forehead numbness, pain, and overall satisfaction.

Statistical analysis was performed using JMP software (version 14, SAS Institute Inc). A 2-tailed, unpaired t test was used to analyze the mean aggregate FWA scores as previously described.¹³ For additional statistical validation, visual analog and Likert-type scales were separated and analyzed independently using a 2-tailed Mann-Whitney test for independent, nonparametric data. Differences at P < .05 were considered to be statistically significant.

Surgical Technique

In the endoscopic browlift procedure, 5 minimal access points just inside the hairline were made at a single median position, paired paramedian positions, and paired temporal positions. A subperiosteal elevation was used in the forehead, and planes between the superficial layer of the deep temporal fascia and temporoparietal fascia in the temporal regions were connected to the subperiosteal cavity in the forehead. The arcus marginalis was bluntly released along the entire level of the superior orbital rims from lateral canthus to lateral canthus using a flat elevator. The release of the arcus marginalis was complete to expose subcutaneous fat laterally and the brow musculature medially. Care was taken to identify and preserve the supraorbital neurovascular pedicles. At this point, the forehead soft tissue was lifted and suspended with percutaneous screws at the paramedian incisions. Laterally the temporoparietal fascia was lifted and sutured into the deep temporal fascia with 3-0 polydioxanone suspension sutures. A suction drain was brought out of a small stab incision in the temporal hair.

In the patients who underwent browlift with glabellar myectomy technique, the procerus and corrugator muscles were divided and partially removed after complete release of the arcus marginalis (Figure 2). The myectomy was performed by using insulated endoscopic grasping forceps to gently grab the fibers of the corrugator and procerus muscles and strip them. The location of the supratrochlear neuromuscular bundle was identified by our previously described technique of using the vertical glabellar crease as a topographic landmark.¹⁴ In that study, transcutaneous pin placement through the vertical glabellar rhytids consistently approximated the supratrochlear neurovascular bundle during endoscopic visualization. The myectomy then involved removal of redundant muscle tissue after stripping. This movement was repeated until the supratrochlear nerves and blood vessels could be visualized, and the glabellar musculature was completely released. The remainder of the operation was then performed similarly to the group who did not undergo myectomy.

Figure 2. Intraoperative Photographs of Glabellar Muscle Resection.

A, Release of the arcus marginalis and exposure of the right corrugator supercilii and procerus muscles. B, Resection of the right corrugator muscle. C, Resection of the procerus muscle. D, View of subcutaneous fat in glabellar region with procerus and corrugator muscles having been divided. The letter C set within the operative areas in several of the panels indicates corrugator supercilii; P, procerus.

Results

The 12-month postoperative improvement in neutral gaze glabellar wrinkle scores were 1.28 and 1.00 (P = .38) for the glabellar myectomy and control groups, respectively (Table and Figure 3). The 12-month improvements in furrowed gaze glabellar wrinkle scores were significant at 2.56 and 1.07 (P = .01) for the glabellar myectomy and control groups, respectively (Figure 4). The 12-month improvements in neutral gaze forehead wrinkle scores were similar at 1.0 and 1.1 (P = .70) for the glabellar myectomy and control groups, respectively. The 12-month reductions in raised brow forehead wrinkle scores were similar at 1.19 and 1.29 (P = .86) for the glabellar myectomy and control groups, respectively.

Table. Glabellar and Forehead Wrinkle Assessment Scores.

Facial State	Preoperative			12-Month Postoperative			12-Month Reduction
	Myectomy (n = 16)	Control (n = 7)	P Value	Myectomy (n = 16)	Control (n = 7)	P Value	Myectomy (n = 16)	Control (n = 7)	P Value
Glabella Wrinkle Scores, Mean (SD) [95% CI]
Neutral gaze	1.90 (0.54) [1.64-2.23]	2.60 (1.67) [1.03-4.12]	.36	0.60 (0.65) [0.31-1.00]	1.60 (1.48) [0.20-2.9]	.16	1.28 (0.60) [0.95-1.60]	1.00 (0.71) [0.35-1.65]	.38
Dynamic motion	4.30 (1.17) [3.66-4.90]	4.30 (1.25) [3.13-5.45]	.99	1.70 (1.21) [1.07-2.36]	3.20 (1.44) [1.88-4.55]	.04	2.56 (1.54) [1.74-3.38]	1.07 (0.79) [0.34-1.80]	.01
Forehead Wrinkle Scores, Mean (SD) [95% CI]
Neutral gaze	1.80 (0.87) [1.38-2.31]	2.30 (1.14) [1.30-3.42]	.31	0.80 (0.75) [0.45-1.24]	1.20 (0.70) [0.57-1.86]	.27	1.00 (0.58) [0.69-1.31]	1.10 (0.85) [0.35-0.93]	.70
Dynamic motion	4.00 (1.37) [3.23-4.76]	4.40 (0.85) [3.57-5.15]	.46	2.80 (1.55) [1.88-3.59]	3.10 (1.69) [1.50-4.64]	.66	1.19 (1.05) [0.63-1.75]	1.29 (1.22) [0.16-2.4]	.86

Figure 3. Photographs of Browlift Patients With and Without Myectomy at Neutral Gaze.

A and B, Browlift plus myectomy patient preoperatively (A) and 12 months postoperatively (B). C and D, Browlift-only (control) patient preoperatively (C) and 12 months postoperatively (D). The 12-month postoperative improvements in neutral gaze glabellar wrinkle scores were 1.28 and 1.00 (P = .38) for the glabellar myectomy and control groups, respectively. These patients’ scores reflected the mean values for their respective myectomy and control groups.

Figure 4. Photographs of Browlift Patients With and Without Myectomy at Furrowed Gaze (Dynamic Glabellar Contraction) .

A and B, Browlift plus myectomy patient preoperatively (A) and 12 months postoperatively (B). C and D, Browlift-only (control) patient preoperatively (C) and 12 months postoperatively (D). The 12-month postoperative improvements in furrowed gaze glabellar wrinkle scores were 2.56 and 1.07 (P = .01) for the glabellar myectomy and control groups, respectively. These patients’ scores reflected the mean values for their respective myectomy and control groups.

Extensive release and resection of the corrugator and procerus muscles was almost invariably associated with good repositioning of the brow line. Some patients with more elastic tissues obtained radical reductions in glabellar wrinkle lines with scale level decreases of 4 levels, while a few with inelastic tissues achieved mild glabellar wrinkle reductions of only 1 level. There was no patient who underwent corrugator and procerus myectomy who did not have improvement in their observer glabellar wrinkle score at 1 year postoperatively. Blinded observers also graded 100% of the patients as appearing “more refreshed” in their 1-year postoperative photographs compared with their preoperative photographs, in both the myectomy and the control groups.

On patient postoperative questionnaire forms, both groups reported minimal to no pain. Among the myectomy group, 15 of 16 patients reported no pain, and the remaining patient reported mild pain. Among the control group, 6 of 7 patients reported no postoperative pain, and the remaining patient reported mild pain. Regarding forehead numbness at 3 months in the myectomy group, 9 of 16 patients reported none, 6 of 16 reported mild, and 1 of 16 reported moderate. By 12 months, 15 of 16 patients reported no numbness, and 1 of 16 reported mild numbness. In the control group at 3 months, 4 of 7 reported no numbness, and 3 of 7 reported mild numbness. By 12 months, 6 of 7 reported no numbness, and 1 of 7 reported mild numbness. Regarding muscle weakness at 3 months, in the myectomy group, 12 of 16 patients reported none, and 4 of 16 reported mild. By 12 months, 15 of 16 patients reported no weakness, and 1 of 16 reported mild weakness. In the control group at 3 months, 5 of 7 reported no weakness, and 2 of 7 reported mild weakness. By 12 months, 6 of 7 reported no weakness, and 1 of 7 reported mild weakness. Regarding satisfaction with the procedure at 3 months, in the myectomy group, 12 of 16 patients reported that they were largely satisfied, 2 of 16 reported that they were somewhat unsatisfied, and 2 of 16 reported that they were largely unsatisfied. Interestingly, by 12 months, all 16 patients who had undergone myectomy reported that they were largely satisfied with the results. In the control group at both 3 and 12 months, 7 of 7 patients reported that they were largely satisfied with the results. Of note, there may have been a slightly quicker time to complete satisfaction in the control group, since a greater percentage of these patients’ procedures had functional indications and therefore lesser aesthetic goals.

There were no cases of complications within either group, such as hematoma, excessive bleeding, requests for revision, asymmetry, alopecia, or infection.

Discussion

This study exposed robust distinctions between the browlift procedures with and without glabellar myectomy for the degree of wrinkle reduction attained specifically within the glabellar region. During dynamic contraction of the brow, more than double the wrinkle reduction, as measured by the FWA was seen (2.56 vs 1.07, P = .01) in those undergoing corrugator and procerus muscle resection vs controls. The senior author (D.A.S.) often refers to this outcome as “partial permanent botulinum toxin” in preoperative discussions, yielding long-term reduction and prevention of vertical glabellar rhytid formation. The patients in the control group who did not have any division and removal of the glabellar musculature also had improvements in the glabellar wrinkles at rest and during furrowing (wrinkle score reductions of 1.0 and 1.1, respectively). This is likely owing to the traction on the musculature during the browlift procedure. Additionally, cutting the arcus marginalis probably damaged the procerus and corrugator somewhat. Finally, it is possible that the skin stretch during the browlift would increase the tension, so the skin would not furrow as obviously. Meanwhile, these improved outcomes with the incorporation of myectomy techniques did not result in any increased risk of complications. There were no complications in the myectomy group such as hematoma, glabellar flattening, or medial brow lateralization. Additionally, there were no significant differences between myectomy and control groups from patient survey responses regarding pain, motor weakness, or numbness.

Limitations

Although minimally invasive techniques and avoidance of muscle manipulation occupy center stage in the public eye, our data present compelling evidence to promote a more aggressive tack. Our study is not without limitations, however. The arbitrary method of testing used was perhaps a necessary evil, since no accepted standard exists for the objective measurement of facial rejuvenation procedures in the aging face. The wrinkle assessment scale chosen may have overexposed or underexposed real or imaginary differences in the intraoperative outcomes. However, the evaluators uniformly described the patients as “more refreshed” in their postoperative photographs. Further fortification evaluation methods might have disclosed an even more vigorous disparity between the groups.

And what can be made of the sticky question of purported drawbacks of glabellar myectomy? Some surgeons predict eventual muscle regrowth and limited benefits of this maneuver. The data presented here demonstrate the persistent improved outcomes beyond 12 months postoperatively, well beyond the time frame of when one would expect some muscle regrowth. Surgeons who oppose extensive muscle resection techniques will point to conservative decreases in the wrinkle assessments as evidence of a lack of clinical utility, despite the statistical significance of our results. These measures should not be disparaged. The human eye is capable of almost submillimetric discrimination between features.¹⁵ Surgeons exploit this attribute to achieve natural enhancements via subtle changes.

The chief limitation of this study lies in the inability to reproduce such measures to establish the long-term stability of the benefits achieved beyond 1 year postoperatively. Our data serve to elucidate these conclusions, notwithstanding the intrinsic weaknesses of past inferences derived from subjective and photogrammetric evaluations. In absolute terms, the slightest improvements were achieved in the glabella. In relative terms, the glabella was proportionately the greatest beneficiary in this study, with more than double the wrinkle improvement achieved compared with browlifts without muscle resection. Erosion of the browlift improvements by parallel aging of all facial subunits might demonstrate the benefit of the improvement in the glabellar wrinkle lines. In other words, the glabellar wrinkles do not have as far to age in the years following a browlift. The resection of the corrugator and procerus muscles should diminish the repetitive skin contractions and wrinkle formation. Intuition suggests that these proportionate changes, however small, should be maintained with passage of time, thereby preserving the relative superiority of the myectomy technique over its less invasive alternative techniques. Although something must be said for clinical experience and instinct, the lasting effects of a technique cannot be fully endorsed by intuition alone. Further answers to this worthy question will perhaps be borne out with time and improved study techniques.

Conclusions

The ultimate driver of our specialty, more than any other, is patient satisfaction. Browlift of any kind has long been associated with a high level of patient approval ratings, which necessitates population surveys of such a large scale so as to render them nearly impossible. Many surgeons are understandably discouraged from initiating extended techniques such as corrugator and procerus muscle resection to improve on what is already considered a reliable operation. The recent resurgence of minimally invasive techniques is a testament to our need to answer to other patient demands such as negligible risk and minimal downtime. On the other hand, a technique’s capacity to provide an unquestionably greater improvement of enduring longevity can weigh heavily in a patient’s decision-making process. As with any study, deductions drawn from our data fall within the realm of interpretative experience. Our data strongly demonstrate a reduction in dynamic glabellar wrinkles associated with the myectomy procedures, with no increased risk of complications or adverse effects. We believe that these intraoperative findings support our continuing experience of a natural and lasting forehead and glabellar enhancement achieved using the corrugator and procerus myectomy technique.