Radiofrequency (RF) devices are used to destroy cancer cells through heat generation. However, they can also be used for skin rejuvenation, such as tightening, dermal remodeling, and fat remodeling [1,2].

In recent years, several types of RF devices have been developed and used for non-invasive lower eyelid rejuvenation [3]. Among them, Inus is unique in that it delivers its bipolar RF current through a specialized vacuum edge line, ensuring optimal needle insertion into sensitive areas with high skin laxity, such as the eyelids and neck [4].

Clinical manifestations of aging lower lids include deflation and laxity with wrinkles, protruding orbital fat, increased vertical length of the lid-cheek junction (LCJ) with development of tear trough deformity, palpebromalar groove, and continuation of mid-cheek furrows [5]. The challenges with lower lid rejuvenation are the anatomical abutments of the eye and surrounding regions, such as the midface and temple.

To date, incisional lower blepharoplasty is still recognized as the most effective surgical treatment; however, improvements following non-surgical treatment are almost equivalent [6].

Monopolar fractional microneedle radiofrequency (FMR) has been used as a non-surgical treatment for facial skin rejuvenation. However, to date, there is no report on the application of bipolar FMR for the rejuvenation of lower lids.

This study aimed to evaluate the rejuvenating effect of Inus, a bipolar FMR device, on the aging lower lids, lateral canthal regions, and temporal hollows.

Patient group and follow-up

From July 2017 to August 2017, 11 female who underwent Inus treatment, with relatively good follow-up, in the Seoul Cosmetic Surgery Clinic were chosen as study participants. The total number of cases was 22, and the total follow-up period was 8 weeks.

Application of Inus

The Inus unit was developed by Medromed Division Ltd. (Seoul, Korea) to rejuvenate eyelids. It is equipped with a specialized apparatus known as the vacuum edge line that allows easy and precise insertion of microneedles into lax skin with a reduced degree of pain and swelling during the procedure [4].

Topical anesthesia was applied to the treated area for an average of 45 minutes. Following disinfection using benzalkonium chloride solution (10%), a temporary Inus tip with 25 microneedles was gently placed in contact with the skin of the orbital and periorbital regions, including the proximal skin of the midface, lateral canthal regions, temporal hollows, and lateral brows, in a vertical orientation.

Inus of 0.5 or 2.0 MHz was used with microneedles of depth 1.0 mm or 0.8 mm, respectively, on the entire lower lid during three sessions, held at intervals of 2 weeks each [4].

Because the peripheral skin was drawn into the vacuum edge line by negative pressure, 25 microneedles were simultaneously inserted into the central skin (Table 1; Supplementary Video). Throughout the procedure, 3.0 ml of multi-peptide mesotherapy solution (MISTCELL; Meso Pharmaco., Ltd., Seoul, Korea) was continuously applied to the lower lid and surrounding skin.

Table 1 . Inus parameters of the fractional radiofrequency microneedle in the authors’ study [4].

Parameter	0.5 MHz bipolar mode		2.0 MHz bipolar mode
	First pass		Second pass
Treatment site	Entire lower lid, lid cheek junction, and lateral canthal area
Depth of needle (mm)	1.0		0.8
Intensity of power (W)	0.88		0.66
Pulse width (ms)	130		140
Suction interval/level	0.5s/1		0.5s/1
Mean tip count	Range, 90–110/each eyelid

Postoperative care and consent

After the procedure, the patient was instructed to apply an antibiotic ointment to the treated area for 2 days. Adequate oral hydration and the use of cosmetics for proper skin hydration were recommended, and sunscreen was applied two days after the procedure. Each patient was given the opportunity to review the manuscript and consented to publication.

Measurement of shape change; horizontal palpebral width, canthal tilt, and lid-cheek junction

Pre- and postoperative photographs were taken during the first visit and 2 weeks after the third session, respectively. From the pre-and postoperative photographs of the patient, the horizontal palpebral width, canthal tilt, and vertical length of the LCJ were identified and estimated using a protractor, as shown in Fig. 1.

Figure 1. Measurements of the horizontal palpebral width, canthal tilt, and distance of lid-cheek junction. a) a line between the medial and lateral canthi, b) a transverse parallel line from the medial canthus, c) lid-cheek junction, d) a vertical line of the lateral canthus, and e) a vertical line of the medial canthus. Blue-colored round arrow indicates canthal tilt; yellow-colored transverse arrow, horizontal palpebral width; white-colored vertical arrow, distance of the lid-cheek junction.

Statistical processing method

As the sample size of 11 patients was too small to verify the effect of the procedure with one method, statistical analyses were performed using two methods for reliable verification. The mean and standard deviation of the horizontal palpebral widths, canthal tilt, and distance of the LCJ of the patients were calculated, and comparisons were made using a paired t-test and the Wilcoxon signed-rank test, which is a method of analysis using rank. A p-value <0.05 was considered significant. Overall, the effect of the procedure was verified by confirming that the difference before and after the procedure was significant in all parts. All date were analyzed using Wilcoxon-signed rank test (IBM SPSS Corp, Armonk, NY, USA).

Looking at the pre- and postoperative distance of the LCJ in Fig. 2, it can be seen that the length of the left was long among all but two patients; however, after the procedure, the length of the right was longer among all but three patients. When comparing the lengths before and after LCJ treatment, it was found that the difference in length was greater on the left than on the right. Based on this result, it can be predicted that the left side has a greater effect than the right side, as the length of the left side substantially decreased after the procedure.

Figure 2. Pre- and postoperative distance of lid-cheek junction. RT, right; LT, left.

We received the patient’s consent form about publishing all photographic materials.

Statistical analysis

The mean patient age was 55.25±5.25 years, and 7 out of 11 patients had previous transcutaneous lower blepharoplasty (TLB). A statistical analysis of the changes in the horizontal palpebral width, canthal tilt, and LCJ is shown in Table 2. In Fig. 2, the horizontal palpebral width was increased by 0.6 mm on the right side and 0.74 mm on the left side. In canthal tilt, the right side increased by 0.45° on average, and the left side increased by 0.6°. And the distance of the LCJ decreased by 2.2 mm on the right side and by 2.67 mm on the left side.

Table 2 . Changes and variations in the horizontal palpebral width, canthal tilt and distance of lid-cheek junction (LCJ) after Inus treatment.

No. of case	Age (yr)	Horizontal palpebral width (mm)			Canthal tilt (°)			Distance of LCJ (mm)			Past history
		Preoperative (RT/LT)	Postoperative (RT/LT)		Preoperative (RT/LT)	Postoperative (RT/LT)		Preoperative (RT/LT)	Postoperative (RT/LT)		Lower blepharoplasty
1	59	19.6/19.3	19.6/20.1		8.5/7.7	8.7/8.1		15.6/15.9	13.2/13.8		+
2	53	20.9/21.2	21.7/22.0		7.4/5.2	8.2/6.0		14.8/19.1	13.5/12.7		+
3	42	23.0/22.8	23.5/23.5		11.8/8.5	12.9/9.4		18.5/22.0	17.5/16.7		-
4	61	20.9/19.8	21.4/21.7		7.0/6.0	7.1/6.9		19.8/13.5	14.3/12.4		+
5	58	19.1/19.3	19.8/19.9		6.7/5.5	8.0/6.7		17.7/18.3	13.0/14.8		-
6	58	22.2/22.0	22.5/21.7		8.0/8.1	8.6/8.5		15.3/16.9	14.6/15.6		+
7	52	23.3/22.0	23.6/22.8		9.2/7.9	10.0/8.8		16.7/18.8	15.6/14.8		-
8	59	20.9/20.9	23.0/22.0		8.8/8.7	10.0/9.1		13.5/14.8	11.6/13.8		+
9	55	22.8/22.0	23.8/23.0		7.0/6.0	7.0/6.4		17.7/18.3	16.4/15.3		+
10	53	22.8/22.0	23.0/23.3		9.7/10.1	10.4/11.0		18.8/16.7	15.9/15.1		+
11	57	19.6/19.1	19.6/19.1		8.2/7.4	8.3/8.0		13.5/14.0	13.2/14.0		-
Mean	55.25	21.4/21.0	22.0/21.7		8.4/7.4	9.0/8.0		16.5/17.1	14.4/14.5
SD	5.25	1.6/1.3	1.6/1.5		1.5/1.5	1.5/1.4		2.2/2.5	1.8/1.3
p-valuea)		0.009/0.001			0.024/<0.001			0.002/0.001
Median		20.90/21.20	22.49/21.96		8.20/7.70	8.30/8.10		16.70/16.90	14.30/14.80
Q1–Q3b)		(19.60–22.75)/ (19.30–21.96)	(19.84–23.50)/ (21.10–23.02)		(7.00–9.16)/ (5.97–7.70)	(7.71–10.01)/ (6.48–9.14)		(14.80–18.50)/ (14.80–18.80)	(13.20–15.90)/ (13.80–15.30)
p-valuec)		0.008/0.007			0.041/0.003			0.003/0.005

RT, right; LT, left..

^a)Paired t-test, any statistical hypothesis test in which the test statistic follows a Student’s t-distribution under the null hypothesis; ^b)Q1–Q3, standard deviation; ^c)Wilcoxon signed rank test, a non-parametric statistical hypothesis test used either to test the location of a population based on a sample of data, or to compare the locations of two populations using two matched samples..

Morphological analysis

Fine wrinkles

In almost all cases, static and dynamic wrinkles significantly improved in the lateral and medial regions of the lower eyelids (Fig. 3-6).

Figure 3. Photos of case 4. (A) Before and (B) 2 weeks after the third session of Inus (8 weeks after the first session). A 61-year-old female who underwent transcutaneous lower blepharoplasty complained about lax, deflated, and wrinkled lower lids with depressed scars. Preoperatively, ectropion due to lid laxity was observed. Postoperatively, the lower lids show significant volume increase and lifted appearance in the superolateral direction. Additionally, the contour of lower lids was also changed from a rounder to a straighter shape. Tightened lower lids with upwardly shifted lid position and increased canthal angle are observed. Eventually, it leads to improvement of ectropion and wrinkles.

Figure 4. Photos of case 5. (A) Before and (B) 2 weeks after the third session of Inus (8 weeks after the first session). Three sessions of Inus treatment were performed on a 61-year-old female who did not want invasive rejuvenation treatment. Preoperatively, due to her well-developed zygomatic bones, her lower lids look relatively tightened compared to that in case 4. Instead, lax skin and wrinkles with protruded orbital fats and deep tear trough deformity combined with deep mid-cheek furrows are observed in the maxillary regions. Postoperatively, the lower lids are tightened and volumized with a reduction of protruding orbital fat, and significant improvement of tear trough deformity and mid-cheek furrows are observed. This case shows that the volume improvement effect was better than that of wrinkle improvement.

Figure 5. Photos of case 6. (A) Before and (B) 2 weeks after the third session of Inus (8 weeks after the first session). Inus was applied to improve fine wrinkles and irregularities with whitish linear scars and syringoma on a 61-year-old female who underwent transcutaneous lower blepharoplasty. Post-treatment, the whole surface of the lid skin looks smooth and tightened, and a substantial reduction of syringoma and linear scars are observed. Wrinkles near the medial canthal regions are significantly reduced. However, transverse wrinkles, as an unexpected complication, are found near the lid-cheek junction (arrow). Interestingly, improvement of large skin pores below the lid-cheek junction is also seen.

Figure 6. Photos of case 7. (A) Before and (B) 2 weeks after the third session of Inus (8 weeks after the first session). Inus was applied to the relatively thin, lax, and wrinkled lower lids of a 59-year-old female who had no history of cosmetic procedures for lower lids. Post-treatment, the entire lower lids become distinctly thickened and significantly volumized. Increased pretarsal volume is also shown. On the other hand, the lid cheek junctions became more distinct with the appearance of deep tear troughs. Simultaneously, significant volume increase below the lid-cheek junctions, as a region of the midface is also seen. Transverse wrinkles become more distinct in the middle of the lid near the lid-cheek junction.

Pretarsal atrophy

Pretarsal augmentation was observed in almost all cases. However, the degree of improvement differed depending on the patient’s preoperative condition. Significant results were observed in case 7 (Fig. 6).

Orbital fat protrusion

Severe and mild orbital fat protrusions in cases 5 and 7 (Fig. 4, 6) were significantly improved. However, as in case 4 (Fig. 3), it appeared to be observed more distinctly postoperatively.

Tear trough deformity

In all cases, the deformity significantly improved, with a more distinct appearance. The entire contour of the tear trough and the palpebromalar groove changed from a V-shape to a round shape (Fig. 3-6).

Deflated lids

In all cases except cases 3 and 11, which had relatively thin lid skin preoperatively (Figure is not shown), the deflated lids were significantly volumized and tightened (Fig. 3-6).

Lid laxity

The shape of the lower lids changed from rounder to straighter, and the position of the lower lids shifted upward. Moreover, decreased lateral angles were observed (Fig. 3-6).

Scars

TLB was preoperatively performed in seven out of the 11 cases. Among them, three cases of depressed scars (cases 1, 4, and 10) and 4 cases of linear scars (cases 2, 6, 8, and 9) were observed. Most scars were significantly improved, as shown in Fig. 3 and 5.

Syringoma

Multiple syringomas scattered in the upper half of the lower lids were significantly reduced, and skin irregularities were also greatly improved (Fig. 5).

Complications

1) Erythema

Transient erythema lasted only 1 or 2 days without any other sequelae (data not shown).

2) Unexpected transverse wrinkles

Obvious transverse wrinkles were observed in the middle part of the lids near the LCJ only in cases 6 and 7 (Fig. 5, 6).

3) Ectropion

Mild eversion of the lower lids was only observed in case 3 (Figure not shown), who had protruded eyes with thin skin preoperatively. However, the patient did not notice or complain of any related symptoms.

A rejuvenating effect of FMR was achieved by combining physical stimulation with microneedles and heating using RF current. This may be due to the promotion of wound healing through dermal remodeling, such as neoelastogenesis, neocollagenogenesis, and, eventually, dermal thickening [7].

Non-ablative FMR devices are known to be effective in treating malar bags and wrinkles, inflammatory acne vulgaris and related scars, large facial pores, primary axillary hyperhidrosis, striae, and skin laxity. However, it is difficult to determine the application of FMR in lower-lid rejuvenation. To date, two cases have been reported on the rejuvenating effect of a monopolar microneedle RF device for lower eyelid fat bulging [8] and a bipolar FMR device for TLB-induced scars [7] on the lower eyelids.

In this study, a bipolar FMR device (Inus) was used to correct aging lower lids in seven patients who underwent TLB and 4 patients who did not undergo TLB.

The entire region of the eyelid had a volumized and lifted appearance owing to the distinct improvement in their contour (Fig. 3-6). The contour and position of the lower lid and lateral canthus changed significantly. This corresponds with the increased horizontal palpebral width, increased canthal tilt, and decreased LCJ (Table 2). Indeed, it is difficult to believe that this lifting does not occur solely because of skin thickening. These results suggest a possible contribution from the complementary stimulation of the underlying muscles and fascia in the orbital, periorbital, and temple regions by the microneedle at a 1.0-mm depth.

Fine wrinkles in the medial and lateral parts of the lower lids were significantly improved (Fig. 3-6). This is mainly due to dermal thickening. The lifted appearance in the superolateral direction influences the severity of wrinkles. However, unexpected transverse wrinkles were observed in the middle part of the lids above the LCJ (Fig. 5, 6). They are thought to be accentuated by the superolateral shifting of the lids and by the direct contraction of the oribicularis oculi muscle by the application of inappropriate needle depth. In this region, the needle depth and RF intensity should be reduced to prevent wrinkles.

The deflated and sagged appearance of the lids and atrophic pretarsus was significantly improved (Fig. 3-6). This can be explained by the well-known rejuvenating effect of FMR. However, pretarsal augmentation and sagging appearance are also influenced by lower lid lifting in the superolateral direction, as is the case with suborbicular oculi fat lifting in the TLB [9].

The contour of the lower lids changed from a round to a straighter shape, and the lid position shifted upward in almost all cases. This result is usually observed after lid laxity correction surgery. Horizontal palpebral width and canthal tilt significantly increased (p<0.05), and the distance of the LCJ decreased (p<0.05). These two results were in good agreement (Fig. 3-6; Table 2). The effects achieved in this study exceeded our expectations.

As reported by Kwon et al. [4], TLB-induced scars greatly improved. Insufficient contact of the tip in the central pre- tarsal regions may result from using a non-needle vacuum edge line or inappropriate needle depths. Therefore, another rectangular tip with ten microneedles in one line is useful for prevention.

It may be argued that the improvement of the tear trough deformity was because the line of the LCJ became more distinct with the appearance of deep tear troughs. This phenomenon may be attributed to two reasons: first, the skin of the tear trough was extremely thin, resulting in a reduced degree of improvement due to inappropriate needle depth; second, the lifting of the orbital, periorbital, and temple regions influenced the depth and texture of the tear trough. Contour changes in the LCJ from a V-shaped to a round shape and decreased distance of the LCJ can explain this lifting hypothesis.

In this study, it may be controversial to describe the effect of orbital fat protrusion because seven out of 11 patients had already undergone TLB, which could not be inserted into the protruded orbital fat. However, it is possible to apply Inus to correct orbital fat protrusion because the length range of the Inus needle is from 0.5 mm to 3.5 mm.

Syringomas are benign eccrine sweat duct tumors typically found in the eyelids and are more common in middle-aged Asian women [10]. The various treatment methods include carbon dioxide lasers, dermabrasion, surgical excision, electrocoagulation, and chemical peeling. Many of these methods are time-consuming, require multiple treatment sessions, and are associated with side effects, such as redness, skin discoloration, pain, blistering, and scarring. Application of Inus improved multiple syringomas without any possible side effects. It is thought that both physical damage and thermal energy irradiated from Inus directly destroyed the eccrine sweat glands.

No serious complications occurred except for temporary mild erythema, 1 case of mild ectropion, and transverse wrinkle formation in two cases. These side effects can be prevented by modifying the RF energy and needle depth and by appropriate selection of patients who do not have protruded eyes with thin skin.

In this report, various benefits of the application of FMR on aging lower eyelids were observed. Some limitations were the low number of cases and short follow-up period; however, the findings suggest that FMR is safe and effective for correcting aging lower lids. A large-scale and well-designed trial may be necessary to investigate the efficacy and safety of FMR further and provide guidelines for treating the ocular and periocular regions.

In conclusion, Inus is recommended as a safe and reliable bipolar FMR device for rejuvenating aged lower eyelids.

Supplementary materials can be found via https://doi.org/10.25056/JCM.2022.6.1.20.

The authors have nothing to disclose.