Eyebrow lifting using multidirectional absorbable thread

Thread lifting is a common procedure in minimally invasive esthetic techniques and can also be used to raise the drooping soft tissue of the forehead by vertically inserting threads into the forehead.


| INTRODUC TI ON
Thread lifting is a widely used facelifting technique because it is less invasive than traditional methods and provides an easy way to move facial soft tissues in the desired direction. 1Thread lifting using insoluble polypropylene was first introduced, followed by thread lifting using absorbable polydioxanone (PDO). 2 Thread lifting is also used to remove wrinkles on the forehead and raise eyebrows.It is also possible to raise drooping soft tissue of the forehead by vertically inserting threads into the forehead. 3 forehead area, there are some important vessels, such as the supratrochlear and supraorbital arteries.Also, it should be considered that the frontal branch of the superficial temporal artery can be located on the lateral side of the forehead.Sometimes, it is useful to check the position of these vessels using doppler ultrasound before the surgery.Since the threads are inside a blunt cannula, this procedure is relatively safer than when using a needle.Also, surgeons should consider the frontal branch of the facial nerve when performing thread lifting on the forehead.
When surveying the satisfaction of patients who underwent forehead lifting at our clinic, patients reported that it was easier to open their eyes and that their eyes appeared larger compared with before the thread insertion.It is known that a relationship exists between the forehead tissue and the opening of the upper eyelid when forehead tissue is elevated.For instance, blepharoptosis is exacerbated when botulinum toxin (Botox) is excessively applied to improve forehead wrinkles, [4][5][6] and a frontalis sling procedure is performed in patients with severe ptosis. 7Thus, we aimed to perform forehead thread lifting and examine the elevation of the eyebrow and improvement of eye opening.

| Materials and Operative Technique
MINT LIFT® UP threads (Multidirectional PDO thread, HansBioMed Co. Ltd., Seoul, South Korea) were used for eyebrow elevation (Figure 1).The threads were designed as multidirectional threads inside a cannula and unidirectional outside the cannula.The threads were 7-10 cm in length for easy handling.In each patient, eight MINT LIFT® UP threads were used on the forehead, and the procedure was performed by inserting a thread upward at four points on the lower margin of each eyebrow (Figure 2).The threads were inserted into the subcutaneous layer, which lays above the muscle tissue.
The study protocol followed the ethical standards of the institutional and national research committee (P01-202103-21-011) and the ethical principles expressed in the Declaration of Helsinki.All patients provided written informed consent.

| Patients
In total, 31 patients who underwent facial thread lifting from March to April 2020 were included in this study (Table 1).Patients who had received any other procedure involving the forehead, including botulinum toxin injection, within 12 months were excluded from the study.MINT LIFT® UP threads were placed on the forehead of all patients.Facial photographs were taken before, and 1 day, 1 week, and 12 weeks after surgery.However, 16 patients were lost to follow-up; therefore, photographic analysis was performed on 15 patients.The ImageJ program (Wayne Rasband, NIH, Bethesda Maryland, USA) was used to measure the degree of eyebrow elevation and eye-opening.First, the center of the cornea was defined as the central point of the line connecting the upper and lower ends of the cornea.To measure the degree of eyebrow elevation, a vertical line was drawn from the center of the cornea to find the point where it met the lower eyelid.From that point, a vertical line was drawn upward to measure the distance to the point where the upper and lower borders of the eyebrows met.The degree of eyeopening was analyzed in terms of marginal reflex distance (MRD) 3, which was measured by drawing a vertical line from the central point of the cornea.MRD 1 was excluded from the analysis because the position of the cornea with respect to the lower eyelid changed during the measurement period (Figure 3).Using the ImageJ program, the distance of the lines on the photograph depends on the inserted scale line.

| Statistical analysis
The paired t-test was used to determine the statistical significance of There was no significant change in eyebrow position immediately after surgery (Table 2, Figure 4).
In the first week after surgery, the upper margin of the right eye-

F I G U R E 4
The effect of forehead thread lifting on eyebrow and upper eyelid elevation.
12 weeks after surgery, with increases of 0.58 ± 0.05 mm (p < 0.05) on the right side and 0.57 ± 0.05 mm on the left side (p < 0.05).
We also analyzed whether the degree of eyebrow elevation was related to upper eyelid elevation.The changes in the upper and lower margins of both eyebrows at 1 and 12 weeks compared with the preoperative state were not significantly correlated with the change in MRD 3 in the corresponding eye (p > 0.05).

| DISCUSS ION
The results of this study indicate that forehead thread insertion can affect the eye-opening system by increasing the maximum elevation of the upper eyelid.However, the lack of a correlation between brow elevation and eyelid elevation implies that the upward traction force itself did not contribute to the increased palpebral height.
To the best of our knowledge, the effect of upper facial thread lifting on the eyelids has not yet been discussed.A helpful point for the interpretation of our results is that the frontalis show compensatory stimulation in cases of severe eyelid ptosis. 8,9This is because the levator palpebrae superioris and frontalis both contribute to eyelid opening, and when the levator is weak, the frontalis is stimulated.Therefore, we hypothesize that thread insertion decreases the function of the frontalis, 10 resulting in increased levator stimulation, which might explain why ptosis was improved by thread insertion into the forehead.Therefore, our findings indicate that the effect of inserting PDO thread into the frontalis muscle on reducing muscle action depends on the level of insertion into the forehead.
To understand the fixation effect of the frontalis, which may explain our results, it is necessary to compare it with the paralytic effect of Botox on the frontalis. 11We empirically assumed that the increased levator function resulting from frontalis paralysis improves eyelid ptosis, but this possibility has not been proven yet.Although the levator is stimulated by Botox injection into the frontalis, this may not suffice to increase the palpebral height, due to the eyebrow depression effect. 12read insertion exerts both fixation and tightening effects. 3erefore, in contrast to Botox, the eyebrow is also elevated.If tightening can contribute to eyelid ptosis correction, a comparable eye enlargement effect to conventional forehead lifting can occur.
However, to our knowledge, there are no reports of enlarged eyes after Endotine forehead lifting.This may be because the tightening effect alone, without stimulation of the levator, has a limited ability to enlarge the eye itself.Therefore, direct eyebrow lifting cannot solve eyelid ptosis; instead, it mostly addresses the problem of excess skin in the lateral third of the upper eyelid. 13,14erall, if levator stimulation occurs due to the fixation of the frontalis and the eye enlarges, this procedure will be a viable option in patients whose levators can be stimulated.Based on clinical experience, the maximal effects of eyebrow lifting last 1-3 months after surgery and can be maintained for more than 6 months; mild blepharoptosis correction occurs for the same duration.Further investigation is needed in the future to identify which patients will benefit from this procedure.
differences in the position of the eyebrow and upper eyelid at four time points during the study period.SPSS version 23 (IBM Corp) was used for all statistical analyses.F I G U R E 1 Image of MINT LIFT® UP.F I G U R E 2 Method of inserting threads into the forehead.TA B L E 1 Patients' demographics.

brow was lowered by 1 .TA B L E 2
70 ± 0.28 mm (p < 0.05) and the lower margin by 1.41 ± 0.16 mm (p < 0.05).The upper margin of the left eyebrow was lowered by 1.68 ± 0.25 mm (p < 0.05) and the lower margin by 1.39 ± 0.16 mm (p < 0.05).At 12 weeks after surgery, the upper margin of the right eyebrow was raised by 1.24 ± 0.34 mm (p < 0.05) and the lower margin by 0.99 ± 0.23 mm (p < 0.05).The upper margin of the left eyebrow was raised by 1.04 ± 0.33 mm (p < 0.05) and the lower margin by 0.73 ± 0.19 mm (p < 0.05).The eye-opening improvement was not significant immediately or 1 week after surgery, but significant changes were observed F I G U R E 3 Measurement landmarks.Landmarks are depicted from above: (1) the upper margin of the upper eyebrow, (2) the lower margin of the upper eyebrow, (3) the margin of the upper eyelid, (4) the center of the cornea, and (5) the margin of the lower eyelid.Effect of forehead thread lifting on eyebrow and upper eyelid elevation.