SUMMARY
The tensor threads have become a great minimally invasive alternative to surgical necklift for some patients.
Luxeface is the first Swiss method in the world for lifting and rejuvenating the skin using absorbable threads.
Developed in 2010 by the Dr Dorina Donici, it is based on a lot of scientific and clinical evidence.
The depth of insertion of the wires, the distance between them, the number and types of wires were carefully studied.
The method is based on 3 treatment steps: regeneration, lifting and restoration of tissue volume.
For each phase, a specific range of uniquely designed threads is designed for a long-lasting natural effect and a short recovery period.
Our article summarizes the mechanisms of action, the numerous indications and different techniques used with this type of resorbable thread.
Keywords: Aesthetic medicine, minimally invasive method, resorbable tensor threads, lifting, rejuvenation, volumizing.
INTRODUCTION
In an aesthetic medicine that is constantly evolving, tensor threads have become a great minimally invasive alternative to surgical neck and face lifts for certain patients.
Luxeface® & Luxebody is the world's first Swiss method of lifting and rejuvenating the skin with absorbable threads, based on over 13 years of scientific and clinical experience.
It was developed in 2010 by the Dr Dorina Donici with the support of A SWISS GROUP.
The author of this method has carefully studied the depth of insertion of the wires, the distance between them, the number and types of wires in order to obtain the best lifting effect and without risk for the patients.
The method is based on 3 treatment steps: regeneration, lifting and restoration of tissue volume.
For each phase, a specific range of uniquely designed threads is designed for a natural, long-lasting effect and a short recovery period.
In only thirteen years, Luxeface has recorded a spectacular performance.
It is a unique concept with a wide range of biocompatible products.
Every month, numerous trainings are held around the world. The Luxeface technique is used in more than 45 countries by over 10,000 dermatologists and plastic surgeons in Europe, the Middle East and Asia.
The combination of innovative insertion techniques and high quality products has brought Luxeface worldwide recognition and impressive success.
Our article is based on the communication from Dr Dorina DONICI during the AIME Marrakech congress in November 2022 summarizing the mechanisms of action, the different indications and the different techniques used with this type of resorbable thread.
PHYSIOLOGY AND BIO-MECHANISM OF TENSOR THREADS
Multiple actions
Luxeface threads have a multiple action: they restore the subcutaneous matrix, stimulate neo-collagenesis, accelerate lymphatic drainage in the intercellular space and increase microcirculation in the tissue. As a result, an anti-oxidant and anti-inflammatory action is obtained.
During skin aging, there is a loss of skin elasticity due to the lack of elastin production and a decrease in firmness due to the decrease in type I and III collagen.
Thus, thanks to the action of these resorbable threads introduced using the Luxeface method, the skin acquires new contours and improves its color, quality and elasticity.
Furthermore, Luxeface® sutures have been scientifically proven to be non-allergenic. The threads are made of polydioxanone (PDO) and polycaprolactone (PCL) alone or combined with poly-L-lactic acid (PLLA) - three biocompatible materials that completely decompose into natural metabolites (H2O, CO2 and glucose).
"Shrink effect - The constriction effect of the fabric
Several studies with histological analysis have been done on the animal model with similarity to human skin. The insertion of these tensor threads was tested at different depths and distances between them. The studies have shown that in order to obtain an optimal result of stimulation of neo-collagenesis, it is essential to insert several Luxeface threads at the same depth and distance between them [1].
After 2 months, the polydioxanone (PDO) threads will form connections between them thanks to the production of type I and type III collagen, thus restoring firmness to the tissue.
After 3 months, the tissues stimulated by the tensor threads acquire a constriction effect. The so-called "Shrink effect" can be observed on the tissues in histology. 
The distance between the tensor wires due to the connections that have been made can decrease to 25 %.
Twist effect
The other interesting point is the mechanical stimulation of the tissues by the tensor threads, which on the one hand synergistically increases the "Shrink effect" of the tissue and on the other hand the rejuvenation effect of the tissues. 
In fact, several scientific studies, particularly histological ones, show that "twisting" the needles several times (on average about twenty times) after the introduction of the tensor threads into the extracellular matrix, allows the latter to be bio-mechanically stimulated.
Thus, the fibroblast cells responsible for the production of collagen, other regenerative peptides and numerous growth factors are activated.
Cellular metabolism
Another interesting biomechanical effect published in a 2013 study [3] is that the introduction of tensor threads stimulates the production of the Rho3 protein. This has an effect on cell metabolism by activating the mitochondria responsible for the production of energy by ATP in the extracellular space. This has an effect on pain, inflammation and tissue elasticity.

Biostimulation of cell metabolism and cell repair: the Rho3 protein.

In 2020, studies [4] have shown that the extracellular matrix, through this mechanical stimulation, activates numerous chemical signals responsible for global tissue repair.
Many studies have been done on the matrisome, which is defined as the set of genes coding for the extracellular matrix containing more than 300 proteins (43 collagens, 36 proteoglycans and many growth factors).
In clinical practice, it has been shown that it is best to perform sessions every 6 months to maintain and boost the production of extracellular matrix components (collagens, proteoglycans, neovascularization...) and thus maintain a lasting firmness of the tissues.
Needles and tensor threads
The Luxeface thread line includes more than thirty types of biocompatible resorbable needles and tensor threads made of polydioxanone (PDO) and polycaprolactone (PCL) alone or combined with polylactic acid (PLLA). The tensor sutures are completely resorbable without risk and without leaving toxic metabolites in the tissue. It is important to work with good needles that do not leave metallic dust in the tissue that can cause inflammatory or allergic reactions or stimulate the creation of fibrosis.

The different needles and tensor threads of the Luxeface® range.

Mono or multi-filament tensor threads.
It is important to know the quality of the notched wire with the type of notches (COG).
Microscope photos of PDO wires: A. Dehydrated with risk of rapid lysis B. Notches (COG) too thin. C. Opening of the notch (COG) not wide enough to catch the fabrics. D. Good quality COG.

THE LUXEFACE METHOD® IS BASED ON THREE STEPS

 

1 - Action of regeneration with "PDO double curled mono needle" threads
First Session: Vertical Insertion
The first session uses the vertical insertion technique. For this, a mono needle with double curled mono needle is used.
For optimal effectiveness, LuxefaceÒ wires should be kept at the same distance from each other (approximately 3 to 5 mm between each wire on the face and 5 to 8 mm on the body) and at the same depth of insertion. This maximizes the constriction effect.
General rules for Luxeface® thread insertion techniques®.
Needles of 27-29 G (gauge) of length 60 mm and wires of length 90 mm should be used with a total of 10 to 15 wires per zone. Insertion should be vertical from top to bottom and from bottom to top while remaining parallel to the nasolabial fold and perpendicular to the mandibular line.
Session Two: Horizontal Insertion
The second session using the horizontal insertion technique should not be done before the third month to increase the effect of tissue constriction. The insertion is done from the outside to the inside, slightly obliquely, going up to the nasolabial fold. Approximately 6 tensor sutures per area are required, with a total of 20 to 25 tensor sutures.

Horizontal insertion technique. 

Here is an example of a patient who benefited only from the Luxeface regeneration step with PDO tensor threads mono double curled and two spaced sessions using the vertical and horizontal techniques. This is a result showing the before and after of the third month following the second session. There is a real effect on tissue firmness.
In conclusion, the regenerative step will have an important influence on the quality of the skin. It improves microcirculation, neo-collagenesis and thus the formation of a new extracellular matrix by using delicate double-looped monofilaments.
2 - Stage of facelift with the double-needle threads
This technique uses polydioxanone (PDO) sutures for a short-term lift and polycaprolactone (PCL) sutures with spiral notches attached to a needle on each side for a long-lasting result.
The aim of the tensor thread insertion techniques is to tighten the various cervico-facial ligament packages.
Although it is often recommended to place the threads in the fatty subcutaneous tissues, the Luxeface technique recommends inserting them as close as possible to the SMAS in order to cling to the fascia in order to obtain an optimal result.
The Luxeface U-shaped insertion technique®.
Diagram of the insertion of single and double needle tensor sutures on a patient.
1- Local anesthesia should be performed with a 30 gauge (G) infiltration needle, 40 mm long. Because of its size, it is not very painful and carries little risk of ecchymosis and hematoma.
2- It is recommended to make the entry point on a capillary area to avoid the risk of scars. It is necessary to use polycaprolactone (PCL) tensor sutures with double 21G needle and 18 cm length. It is recommended to use only one tensor thread with double needle in one area. For more fixation, another double-needled tensor thread can be introduced in another session after 8-12 months. The tensor effect lasts for 3 to 5 years.
3- The first needle enters the scalp up to the superficial temporal fascia, exiting just after the nasolabial fold. If you are in the right plane, the needle and thread advance without any resistance.
4- The second needle enters at the second temporal entry point and exits just before the commissure.
5- The entry points close by themselves. Then you have to adjust the wires and cut them.
6- It is recommended to add the mono tensor threads to the treatment with the rejuvenation step.
7- A Luxeface® mask with arnica, aloe vera and collagen can be applied after the procedure to prevent bruising and reduce swelling.
In conclusion, the lifting step results in a natural and durable fixation. Thanks to flexible cannulas and strong threads, the Luxeface thread can be easily inserted and fixed in any type of tissue.
Another application in clinical practice: fox eyes
The "fox eyes" look is characterized by almond-shaped eyes and a stretched look. Like cat eyes, this eye shape is known to be more seductive, more mysterious, but also softer.
It is a fashion phenomenon that appeals mainly to young women. Some doctors and plastic surgeons may be reluctant to use tensor threads on young women to achieve this effect. They may advise using makeup to obtain this type of look until they have better results. It is important to remain a doctor and to know how to advise the patient with the right indication.
We can then use double-needle tightening sutures type PDO/PCL with spiral notches for the eyebrow lift. The duration of the result is approximately 2 to 3 years and sometimes up to 5 years.
The infiltration is done with a 30 gauge needle. There are several possible marking lines for the fox eyes (red and yellow line). A marking of the exit of the needles below the eyebrow can be done with a felt pen. It is necessary to use one or two entry points.
The method consists of bringing the needles and wires in through the scalp to the SMAS fascia and out at the eyebrow.
Example of "fox eyes" makeup in comparison with tensor threads.
We can then use double-needle tightening sutures type PDO/PCL with spiral notches for the eyebrow lift. The duration of the result is approximately 2 to 3 years and sometimes up to 5 years.
The infiltration is done with a 30 gauge needle. There are several possible marking lines for the fox eyes (red and yellow line). A marking of the exit of the needles below the eyebrow can be done with a felt pen. It is necessary to use one or two entry points.
The method consists of bringing the needles and wires in through the scalp to the SMAS fascia and out at the eyebrow.
3 - Restoration stage of the volumes
The goal is to restore the natural volume of the skin by inserting tensor threads. The implantation of classic spring threads allows the correction of wrinkles by the formation of a new collagen matrix around the thread.
CONCLUSION
Tensor threads have become a great alternative to surgical necklifts for some patients. For the Luxeface method, the depth of insertion of the threads, the distance between them, the number and types of threads have been carefully studied in order to obtain the best lifting effect without risk for the patients.
The method is based on 3 treatment steps: regeneration, lifting and restoration of tissue volume. It is the first method in the world structured in stages that has proven the therapeutic effect of threads in addition to the aesthetic result.
The indications for use are numerous: wrinkles and fine lines, fox eyes, crow's feet, acne and post-acne scars, facial asymmetry, lowered eyebrows, nasolabial folds, ptosis of the skin, hyperpigmentation, changes in skin relief.
REFERENCES
  1. Skin rejuvenation to make use of absorbable PDO thread in regenerative medicine. Jung-Hyun Yoon, 2013.
  2. Mechanical signaling through connective tissue:a mechanism for the therapeutic effect of acupuncture. Langevin H.M., Churchill D.L., Cipolla M.J. Department of Neurology, University of Vermont, Burlington, Vermont 05405, USA Vol. 15 October 2001 The FASEB Journal.
  3. Helene M. Langevin Apr 30, 2013, The Science of Stretch. https://www.the-scientist.com/features/the-science-of-stretch-39407
  4. Sparavigna A. Role of the extracellular matrix in skin aging and dedicated treatment - State of the art. Plastic and Aesthetic Research. 2020; 7:14. https://parjournal.net/article/ view/3396
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