ABSTRACT

‍For many patients, it is important to improve skin quality and to appear younger. Many aesthetic treatment methods are used for this purpose. The objective of this study is to investigate the effectiveness of PLLA on skin quality. Two groups of patients took part in the study. The first group received only PLLA/PCL Aptos threads and the second group received HIFU and PLLA /PCL Aptos thread combined treatment. The treatment covered a 3-month period. The differences before and after the treatment were assessed with the help of photographs and a statistical program. The results were evaluated by both the patient and the doctor. By means of a survey, the evaluations concentrated on skin hydration, color, fine lines, jawline, mouth lines, eye lines, skin elasticity, and thread pain. The survey data revealed improvements for 65% of patients in the PLLA/PCL Aptos thread group and 76% of the patients in the combined treatment group. Specifically, the jawline, mouth lines and skin elasticity results showed a high degee of improvement. The results showed that, PLLA/PCL Aptos thread has a significant effect on skin quality. In addition, the treatment reduces fine lines, increases flexibility and creates a younger and brighter appearance.

KEYWORDS

PLLA, Poly-L-Lactic Acid, skin quality, skin hyration, aptos thread lift, skin elasticity, Ulterapy, HIFU


INTRODUCTION

1. Skin structure

‍The skin is a sense organ that covers the body. It regulates the body temperature, gets pale with sweating, serves as both a thermostat and a protection barrier (1-3). Its thickness is between 1 mm and 4mm. It is the largest and heaviest organ of the body, constituting 16% of the total body weight. The thinnest skin is to be found on the eyelids while the thickest on the sole of the foot. The basic structure of the skin has three different layers:
Epidermis: It is the outermost layer of the skin that acts as a protective layer. The skin renewal takes place in this layer.
Dermis: It is the middle layer which is effective in the durability of the skin. Hair follicles, sweat glands and sebaceous glands are found in this section.
Hypodermis: An inner layer of subcutaneous fat. It provides energy to the skin and is responsible for the insulation function1-3.
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2. Poly-L-Lactic Acid (PLLA)

‍Poly-L-Lactic Acid (PLLA) based filler was first introduced in Europe in 1999 under the trade name ”New Fill” and then in 2004 in the United States market under the trade name Sculptra L for use in HIV-related lipoatrophy cases. Approximately 150,000 patients were treated in the 10-year period after use9,10. Several studies have been conducted on PLLA safety, efficacy and persistence11-13. PLLA is mostly used in the face but there are sources in the literature that show it can be used in other areas. PLLA has been used as a suture material and absorbable screw for approximately 40 years in medicine. Its biocompatibility and efficacy have been shown in previous studies. In a study conducted in Brazil in 2008, it was reported that the injection to nasolabial folds still persists after 3 years14. PLLA creates a foreign tissue reaction at the site where it is applied, increasing the number of macrophages, mast cells and lymphocytes in that region, decreasing fibroblastic activity and increasing neocollagenesis slowly15. New collagen formation appears at 1 month, and until the 9th month, the formation is observed to increase. In the previous studies the PLLA particles showed signs of disappearance in the 6th month and they are eliminated completely in the 9th month 15.
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METHODOLOGY

The experiment was performed on patients aged between 34 and 61 years old, some of whom had undergone medical aesthetic treatments, while the remaining patients had not. The participants were divided into 2 groups. There were 10 participants in each group. Information about the groups is given below: Group 1: In this group, 10 patients received APTOS brand PLLA/CL. No other medical aesthetic procedures were performed at the same time and no other medical aesthetic procedure was performed for 3 months. Group 2: In this group, 10 patients were treated with HiFu application and PLLA / CL were applied to the face during the same week. No other medical aesthetic procedure was applied for 3 months.
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After the applications, the participants were evaluated with VAS questionnaire from 0 to 10 points. Thewith VAS questionnaire from 0 to 10 points. The questions were answered by both the practitioner and the participant before, during and after the application twice, first, 1 month after the application and then 3 months later. The skin color and stains, skin moisture, fine lines, elasticity and sag (especially in the jaw line) were evaluated. A statistical program and photographs were used to evaluate the results. Statistical analyses were performed using SPSS software (version 25.5). Basic descriptive statistics were assessed to describe the survey results as the means ± standard deviations.
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RESULTS

The total VAS score is shown in Table 1 and Figure 2. In the first group of patients undergoing PLLA/PCL Aptos thread, the total VAS score of the patients was 30.60±6.5 before the treatment and 37.5±6.88 after the treatment. This value was determined as 50.5±4.6 3 months after the treatment. These results indicate a improvement of 65% after a 3 month-treatment according to patient evaluation. The total VAS score was found to be 32.8±6.08 before the treatment and 53.0±5.92 after 3 months of treatment, and the healing rate was 62% according to doctor evaluation.
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In the second group with HIFU and PLLA/PCL Aptos thread combined application, the total VAS score was found to be 30.8±11.9 before the treatment, 39.6±11.5 after the treatment, 46.2±9.97 1 month after the treatment and 54.2±8.48 3 months after the treatment. The rate of recovery was 29% after treatment, 50% after 1 month of treatment and 76% after the 3 month-treatment. In this group, the total VAS score was found to be 35.9 ± 9.82 before the treatment and 55.8 ± 7.65 after the treatment and the recovery rate was found to be 55% according to doctor evaluation. Table 2 shows the skin characteristics according to the patients. In the evaluation of the study, the skin hydration was found to be 5.10 ± 1.79 before the treatment in the first group and 7.20 ± 1.31 the third month after the treatment. In the second group, the mean pre-operative average was 4.5 ± 2.8, and the mean value after treatment was 3.40 ± 2.01. Skin hydration increased by 42% in the first group and 65% in the second group.
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Before the treatment the mean skin color was 4.90 ± 2.42 in the first group and 4.8 ± 2.29 in the second group. In the first group, mean skin color was measured as 5.30 ± 2.00, 1 month after the treatment and as 6.01 ± 0.56, 3 months after the treatment. In the second group, the mean skin color was 6.50 ± 2.41 after 1 month and 7.20 ± 2.20 after 3 months of treatment. An improvement of the skin color was observed by 22% and 50% for the first group and the second group respectively. The presence of fine lines was determined as 6.5 ± 2.71 in the first group and 5.2 ± 3.15 in the second group before the treatment.

At the end of the treatment, there was an improvement of 17% in the first group and 50% in the second group. In the evaluation of the jaw line, the mean value was 3.30 ± 1.63 in the first group and 3.4 ± 1.57 in the second group before the treatment. The evaluation on the third month following the treatment revealed that, the mean of the first group was 8.0 ± 0.94 and the second group was 8.30 ± 1.15.

The flatness and tension of the jaw line increased by 142% in the first group and 144% in the second group. The recovery rate of the lines around the mouth was 112% in the first group and 142% in the second group. The improvement in the lines around the eyes was recorded at 25% in the first group and 58% in the second group. In the evaluation of skin elasticity, the mean pre-treatment in the first group was 3.30 ± 1.33, 5.01 ± 0.05 1 month after the treatment and 6.90 ± 0.87 3 months after the treatment. In the second group, the mean pre- treatment, 1 month after the treatment and 3 months after the treatment was 4.6 ± 1.83, 6.51 ± 0.26 and 7.60 ± 1.26 respectively.

The increase in skin elasticity was 109% in the first group and 65% in the second group. During the treatment, the pain level was determined as 7.20 ± 2.04 in the first group and 9,6 ± 0,69 in the second group. Table 3 shows the skin characteristics evaluations by the doctor. The skin hydration was evaulated at 5.10 ± 1.79 before the treatment in the first group and 7.70±0.82 the third month after the treatment. In the second group, the pre-treatment average was 5.1±1.83, and the mean value after 3 months of treatment was 7.80±1.81. Skin hydration increased by 50% in the first group and by 53 % in the second group.
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The mean skin color was 4.8±2.52 in the first group and 5.50±2.22 in the second group. In the first group, skin color after 1 month was measured as 5.40±2.01, and after 3 months of treatment as 6.40±1.57. In the second group, the skin color was 7.30±1.88 after 1 month and 7.90±1.72 after 3 months of treatment. An improvement of the skin color was observed at 33 % for the first group and 44 % for the second group.

The presence of fine lines was determined as 6.50±2.79 in the first group and 5.90±2.68 in the second group before the treatment. After the end of the treatment, there was an improvement of 17% in the first group and 36 % in the second group. In the evaluation of the jaw line, the mean value was 3.20±1.93 in the first group and 4.10±1.52 in the second group before the treatment. 3 months after treatment, the mean of the first group was 8.40±0.96 and the second group was 8.20±1.13. The flatness and tension of the jaw line increased by 162% in the first group and by 100% in the second group. The recovery rate of the lines around the mouth was 130% in the first group and 93% in the second group. The linesaround the eyes were improved by 33% in the first groupand by 32% in the second group.

In the evaluation of skin elasticity, the mean pre-treatment in the first group was 3.10±1.37, 5.20±1.03 after 1 month of treatment and 7.30±1.15 after 3 months of treatment. In the second group, the mean pre-treatment, after 1 month-treatment and after 3 month-treatment was 5.20±1.54, 6.90±1.37 and 8.0±0.81 respectively. The increase in skin elasticity was 135% in the first group and 54 % in the second group. During the treatment, the pain level was determined as 7.70±1.49 in the first group and 9.70±0.48 in the second group.
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DISCUSSION

The main reason for patients trying an aesthetic treatment is to counteract the symptoms of ageing. However, most facial treatments and methods offer relief only for some wrinkles or shrink-wrapped failing skin outwardly responding to the volume and forms of a fresh face. Injectable poly-L-lactic acid is a biodegradable artificial polymer for the improvement of lipoatrophy and is widely used in Europe. Sculptra was famously applied for improvement of nasolabial folds, lack of medial and lower face volume, jawline slack, and anothertype of facial ageing. Sculptra treatment is a minimally invasive and efficient method.

There are main directions for the application of PLLA: bone resorption, fat death and skin laxity; and at which layer of the face and at what level PLLA is determined depends on the patient’s health17-19. Also, for skin laxity, the contrast happens–as PLLA needs to be practised just under the skin, into the subdermal level, with needles or cannulas, but with no fat in connecting tissues. It is in this layer that the best skin quality results can be achieved, which is the idea of this study.

Whenever PLLA is injected into a subdermal plane there is an improvement in skin quality of three types. The first being clear glow-luminosity produced by thehydration of the treated skin, providing the effect of a healthy, young and well-ageing skin. An addditional benefit is the reduction of skin atrophy associated with aging. Moreover, it reduces skin laxity by increasing skin adherence to lower-level tissue. This is normally due to the generation of collagen fibres resulting from the PLLA applications.

In the study carried out by Avelar et al.23 three sessions were applied to the patients at intervals of 45-60 days. Notwithstanding PLLA being supported for many uses - bone resorption, fat loss and skin laxity - there is a regular increase in skin quality after treatment. However, not only is it necessary to know PLLA but also to define the level of injection.

In a previous study, a patient with poor skin quality was treated with a 12-week PLLA treatment. Due to the poor quality of the skin, the first and second treatments were applied for four weeks, allowing sufficient time for collagen restoration and repair. Four weeks after her initial treatment, the patient showed little or no cosmetic improvement. After the second treatment, an improvement of between 20% and 30% in tissue quality was observed according to the comparison of the photos of the patient before and after the treatment and the patient’s opinion on the results of the treatment. Eight weeks after the second treatment, a third treatment was performed to resume collagen repair. No side effects related to treatment were observed. After completing the treatment, visual inspection and skin quality improvement resulted in significant results in terms of elasticity. In addition, as a result of the 12-week PLLA administration, an increase in fibrotic layer in the dermis and subdermal layer and skin shine were observed. In addition, collagen restoration resulted in a healthier skin, reduced pores and a more youthful appearance. No adverse effects were observed during the annual follow-up of the patient.

In another study, participants were treated with injectable PLLA or human collagen for 3 weeks. There is a 3-week period between treatments. For the members of the PLLA group, 3 injection sessions were completed. Three weeks after the last treatment with injectable PLLA, an important development was recognised in the wrinkle assessment scores compared to the baseline. Changes continued to appear until the 13-month evaluation period and were reported during the 19 and 25-month evaluation points. After the injection of PLLA, the number of nodules and papules was 7% and 9%, respectively. Further investigations can serve to maintain the advantage of injectable PLLA performance for aesthetic improvement of facial shape dysfunctions and help manage suitable patient choice criteria for treatment of this strategy29,30. In a similar study, 210 female participants were chosen to correct injectable (PLLA) age and disease-related facial volume deficits. The questionnaire was sent to patients treated with PLLA 6 months earlier or more. After the treatment, some of the patients had papules or nodules. After treatment, some of the patients had papules or nodules. One questionnaire was posted to 281 patients previously treated with PLLA for 6 months or more. PLLA was reconstituted by adding 5 mL of sterile water before injection and 1 mL of 1% xylokine before injection. Patients treated with PLLA had a recovery time of 24months. The maximum improvement was seen after several treatment sessions.

In our study we evaluated the effect of PLLA. Similar to the results reported in the literature, PLLA use increased skin collagen. A skin increase of 42% was observed in the skin group with PLLA. This rate was higher in the HIFU and PLLA group. There was a moderate improvement in skin color. In particular, there was a significant improvement in the jaw line, and both groups had close rates in skin flexibility only. In the PLLA group, a higher rate than in the HIFU and PLLA group was found. This can be considered as evidence that PLLA significantly increases skin elasticity and eliminates the signs of aging. In this study, it was observed that there was little recovery immediately after application. However, a high rate of improvement was achieved 1 month and 3 months after the treatment. This is in line with the studies in the literature.
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CONCLUSION

In this study, we investigated the effect of PLLA/PCL Aptos thread treatment on 20 female patients. The treatment covers a period of 3 months. No side effects were reported by the patients. Evaluations were made through questionnaires and photographs. Both the patient and the physician evaulated the results and similar data were obtained.
• When the survey data were evaluated, an improvement of only 65% in the PLLA /PCL Aptos thread group and 76% in the combined treatment group was observed. These results showed close values in the evaluation of patients and doctors.
• Combined treatment with skin hydration and skin color gave better results.
• In the presence of fine lines, there was a moderate improvement in PLLA/PCL Aptos thread application.
• A high improvement was observed in the jaw line and mouth lines. A smoother and taut image was obtained.
• As for skin elasticity, only PLLA/PCL Aptos threadapplication showed a better result than combined application.

In general, when the results are evaluated, it can be said that PLLA/PCL Aptos thread application is effective on skin quality. This effect depends on the time of the application and the patient’s condition prior to the treatment. A minimal improvement immediately after the application but a high recovery after 3 months emphasize the importance of application time.
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ABBREVIATIONS

PLLA: Poly-L-Lactic Acid
HIV: Human Immunodeficiency Virus
APTOS: Anti-Ptosis
SPSS: Statistical Package for the Social Sciences
VAS: Vısual Analog Scala
HIFU: High Intensity Focused Ultrasound