[Scar Treatment] #2. Recent Trend of Scar Treatment

Treatment of Atrophic Scars

Atrophic scars can be variously categorized depending on the reason: in therapeutic terms, atrophic scar varies from atrophy due to the lack of collagen in the dermis, as in the case of acne scars, to the lack of deep tissues under the adipose tissues due to trauma or surgery. Less invasive laser, peeling and supplements are enough to provide good outcome when dermal defect is the main problem; however, invasive methods, such as fat grafting and surgical removal, are necessary when defects of the adipose tissues and others are accompanied.



1. Treatment of acne scars

Acne scars are the most common condition among scar treatments in dermatology and plastic surgery. As acne scars present as various forms, it is very important to classify and treat them accordingly.



2. Trend of atrophic scar treatment using laser and other devices: listed in the order of development

1) Removal of the epidermis and dermis: Ablation using carbon dioxide or erbium:YAG laser

2) Stimulation of the dermis only without injury to the epidermis: Non-ablative remodeling laser, various radiofrequency devices

3) Deep dermal injury with minimal epidermal injury: Non-ablative fractional laser

4) Appropriate epidermal injury and deep dermal injury: Ablative fractional laser

5) Deep dermal injury without epidermal injury: Focused Ultrasound Devices, Fractional Microneedle Radiofrequency Devices.

Table 1. Goodman GJ,Baron JA, MDyPostacne Scarring: A Qualitative Global Scarring Grading System. DermatolSurg 2006:32:1458-1466.

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Table 2. Goodman GJ,Baron JA, MDyPostacne Scarring: A Qualitative Global Scarring Grading System. DermatolSurg 2006:32:1458-1466.

Figure 1. Treatment of atrophic scar with fractional Laser

Figure 2.Various treatments of hypertrophic scar and keloid

3. filling agents for atrophic scars

Temporary fillers using hyaluronic acid, calcium hydroxylapatite and collagen, as well as permanent fillers using polylactic acid, polyacrylamide and silicone, are commonly used. Recently, the method of correcting scars using autogenous cell has been developed. This so called ‘cell therapy’ attempts to introduce autogenous fibroblasts, adipose stem cells, adipocytes or preadipocytes.



Recent Therapies of Hypertrophic Scar and Keloid

Hypertrophic scars or keloids are not easily treated and only one method is not enough to provide a good outcome. The most traditional method is surgical excision and steroid injection, but recently various new attempts and combination therapies have been introduced. Therapies introduced at Wound forumin 2004 are summarized below.



1. Intralesional excision of keloids

Completely excised keloids tend to become bigger in size, but partial excision can reduce the size of a large lesion enough for injection therapy. Of course the surgical excision not the end of treatment; various other treatments should be combined to maintain the effect of the surgery.

Figure 3. Examples of intralesional excision

Figure 4. Hypertrophic scar treated with PDL

Figure 5. Keloid treated with fractional Laser

Recent studies reported that recurrence of a lesion can be prevented by post-operative application of imiquimod ointment (aldara).



2. Scar treatment using lasers

1) Pulsed dye Laser is known to reduce TGF-beta and to prevent collagen synthesis of fibroblasts by acting on the blood vessels in the scar and making the scar to a hypoxic state.

2) Fractional Laser has been reported recently to provide good outcomes as PDL in the treatment of keloid or hypertrophic scar.

REFERENCES

1. Kelly AP. Medical and surgicaltherapies for keloids. Dermatol Ther2004;17:212-218.

2. Al-Attar A, Mess S, ThomassenJM, Kauffman CL, Davision SP. Keloid Pathogenesis and Treatment. Plast Reconst Surg 2006;117:286-300.

3. Mustoe TA, Cooter RD, Gold M, HobbsFDR, Ramelet AA, Shakespeare PG, et al. International clinical recommendations onscar management. Plast. Reconst Surg2002; 110: 560-571.

4. Connell PG, Harland C . Treatmentof keloid scars with pulsed dye lasers and intralesional steroid. J Cutan Laser Ther2000; 2:147-150 .

- To be continued -

▶ Previous Artlcle : #1. Definition and Pathological Study of Scars

▶ Next Artlcle : #3. Drugs and Topical Agents for Hypertrophic Scar and Keloid Treatment I

[The Principle and Application of Laser(with focus on medical lasers)] #2. Development Process and Types of Lasers

3. Development Process and Components of Lasers

3-1. Development process of lasers

All lights are generated by atoms or molecules. An atom is composed of a nucleus surrounded by electrons. Electrons’ orbit around the nucleus various according to the type of the atom; the same type of atom has the same number of electrons of the same orbit. If an outermost electron is given a light energy from the outside or energy by collision with another electron or atom, the electron moves further to an outer orbit. This state where en electron moves further to the outermost orbit when the atom was given an additional energy is called an ‘excited state’ or ‘excited energy level’. Atoms in ground state have a longer lifetime without a time limit, but can maintain the excited state only for a limited time. As atoms are unstable in excited state, they tend to emit the received energy in the form of light energy and return to the original orbit where they maintain a stationary status. Atoms in stationary status are referred to as in ‘ground state’.That is, light is emitted when atoms or molecules return to the ground state or when the excited state with a higher energy returns to a state with a lower energy. The number of atoms that constitute materials is countless in effect.Since each atom absorbs energy and emits a light individually, the emitted lights have different phases and wavelengths. The process where electrons in the excited states emits photons while spontaneously turning to the ground state is called ‘spontaneous emission’. Light emission from bulbs, fluorescent lights and neon signs are all examples of spontaneous emission. These lights emitted by spontaneous emission are characterized by broad spectrum and incoherence between each other.

On the other hand, stimulated emission refers to the emission of photons in the course of transition from the excited state to the ground state induced by external incident photons. The photons generated by stimulated emission have the same frequency, phase and direction as the photons of the incident wave, presented as coherence. This process appears as if one incident light doubled, making two rays of light of identical nature. A laser is a device that amplifies light through the process of stimulated emission.

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In natural condition of thermal equilibrium, there are generally far more atoms in ground state than those in excited state, thus the probability of stimulated emission is only about 10^-12 . In order to increase the probability of stimulated emission, the number of atoms in excited state has to be higher than those in ground state. Some atoms have a longer lifetime when it becomes excited by absorbing light energy than the time it takes to make transition to a lower energy level. This property can be found in a synthetic ruby, which is made by adding a little bit of chromium ions (Cr³⁺) to a sapphire, crystalline alumina. This gain medium becomes excited when exposed to strong light energy by a Xe or Kr lamp. At this point, the number of atoms in excited state is greater than those in ground state (or in lower energy level), and this state is called ‘population inversion’. If the condition of population inversion is satisfied, stimulated emission becomes amplified like an avalanche while the light passes through the gain medium. However, the amount of stimulated emission is still not enough to generate a laser and a resonator is required to meet the required amount. The resonator is consists of a total mirror, which has 100% reflectivity for laser wavelengths, and an output coupler, which lets some of them transmitted. By placing the gain medium between the two mirrors, the light generated by stimulated emission repeatedly travels between the mirrors reflecting back on itself, until some of the amplified light is emitted through the output coupler as laser light. To put it simply, the following three components are essential to generate laser:

1) A laser gain medium with an energy level that can induce population inversion.

2) A pumping source required for inducing population inversion.

3) An optical resonator for amplifying the light generated by stimulated emission.

4. Laser Types

Lasers can be categorized systematically into solid-state lasers, gas lasers, liquid lasers, semiconductor lasers, etc. The gain medium of a laser defines its wavelength. Characteristics of lasers by systematic categories are described below.

4-1. Solid-state lasers

Solid-state lasers use (amorphous) glass or crystalline ‘host’ material to which active atoms (molecules) are uniformly dispersed as the gain medium. The first laser light in human history produced by Maiman was also a solid-state laser using a synthetic ruby. Solid-state lasers typically use photon pumping method, for which a flashlamp, arc lamp, or laser diode is used.

Solid-state lasers can be subdivided into several types, chiefly such as ruby laser (emission at 694nm), Nd:Glass laser (1.05㎛), Nd:YAG laser (1.06㎛), and tunable laser. Giant pulse can be obtained by Q-switching. Nd:YAG laser, first produced in 1964, is a four-level laser, which is composed of ① ground state level, ② the lower laser level, ③ the upper laser level of metastable state, and ④ pump band level. Nd:YAG is a compound word from the initial letters of Yttrium, Aluminium and Garnet, with some addition of Neodymium (Nd). YAG is the basic material of neodymium, the atoms of which emits strong laser beams at 1.06㎛ (near infrared), and YAG crystals are also excited by strong light such a flash lamp. Among solid-state lasers, ruby laser, alexandrite laser, Nd:YAG laser, Nd:Glass laser, Er:Glass fiber laser, Ho:YAG laser and Er:YAG laser are currently used for medical purposes.

4-2. Gas lasers

Gas lasers use active atoms (molecules) of gas or mixed gas containing them as the gain medium. In gas lasers, excited state can be induced by discharge (plasma) or by electron beam. He-Ne laser (emission at 633nm), carbon dioxide laser (10.6㎛), Argon-ion laser (488nm, 514nm) are commonly used. There are also copper (Cu) vapor laser and excimer laser.

The He-Ne laser, first produced in 1962, is the first gas laser. Although the output power is weak, it can induce stable continuous wave (CW) for a long time, making it still commonly used in measuring.

The carbon dioxide laser, first produced in 1964, is a very powerful laser, with scores of kilowatts of CW output. The energy efficiency is as high as 15-20%, making it useful for laser processing.

The argon laser was first produced in 1964 and is capable of continuous output of about 1W. It commonly uses water cooling system but air cooling system can be used in some cases. It is characterized by the presence of several oscillations between green (514.5nm) and blue (488nm) lasers, contributing to the wide range of visible lasers.

The excimer laser is a high-output UV laser and mostly used for chemical reaction process or medical purposes. Excimer molecules include ArF (emission at 193nm), KrF (248nm) and XeCl (308nm), and the pulsed light has average 50-200W power output. However, the energy efficiency is generally poor at about 0.5-1%. In the excimer laser, atoms of fluorine and krypton, which do not combine in the ground state, becomes excited and combines as an excimer molecule, which is unstable and immediately returns to the ground state, during which the ultraviolet is emitted. This is the principle of the excimer laser. The term ‘excimer’ is short for ‘excited dimer’, which refers to the molecule that exists only in the excited state.

Among gas lasers, excimer laser, copper vapor laser, He-Ne laser and carbon dioxide laser are currently used for medical purposes.

4-3. Liquid lasers (dye lasers)

Liquid lasers use active molecules, such as a dye, diffused through a liquid, such as alcohol, as a lasing medium. Liquid lasers include organic and inorganic lasers and dye lasers; recently, liquid lasers mostly refer to dye lasers. Excitation is typically induced by light. Liquid lasers are easy for tuning wavelengths and the peak output power at 370-720nm reaches scores of kW. The efficiencies of ion laser and excited laser energy are 10-20%. Among liquid lasers, the dye laser at around 600nm is currently used for medical purposes.

4-4. Semiconductor lasers

The semiconductor laser was first demonstrated in 1962 but continuous wave operation succeeded first in 1970. Since then, it went through a series of improvement, and the development of double heterostructure and stripe structure has led to its wide application in fiber-optic communications, CD players, laser printers, laser scanners and laser pointers. It is now produced the most among lasing devices. The basic structure is P-N junction, although the laser diode is of double hetero-structure that has light-emitting layer (active layer) inserted between  the cladding layers on both sides. The laser diode uses the cleaved facet as the total mirror (resonator). GaAs, GaAlAs orInGaAsP is used as the material. Laser diodes are highly efficient, small and lightweight, cheap, and have high energy efficiency of 20-40% for multiple-quantum-well structure and ~25% for P-N type. The continuous output covers from ultraviolet to visible lights, and the development of devices with the optical pulse output of 50W (100ns pulse width) has made it a very convenient laser oscillator for a laser radar and excitation light source.

Among semiconductor lasers, wavelengths at 405nm, 650nm, 810nm, 930nm and 980nm are widely used for medical purposes.

- To be continued -

▶ Previous Artlcle : #1. The birth of laser and its characteristics

▶ Next Artlcle : #3. Lasers and Soft Tissue Interaction Ⅰ

[Regenerative Surgery] #2. Elements of Tissue Regeneration

Defective skin and soft tissue exposing bone or tendon, mostly after injury, infection or tumor surgery, is a major challenge for plastic surgeon. In order to reconstruct the defect, engraftment on the site with tissues that are similar to the injured skin and soft tissue is necessary. Flap operation is commonly available for the reconstruction; however, local flap is limited by the amount, composition and moving range of the flap, while free flap has several other drawbacks, such as the complexity of the operation, longer operation time, and greater loss of donor site. Patients with a chronic wound, such as bedsore and diabetic foot, tend to have poor general condition and tissue flow. For these patients, it is more difficult to perform a flap operation.



Recent development in biotechnology has made it possible to make the tissues to be reconstructed by isolating and culturing cells. Particularly, adipose cells are relatively easily obtainable in considerable amount while minimizing the loss of the donor site; thus, there have been efforts to isolate Adipose Derived Stromal Cells (ADSCs) and, through cell culture and differentiation, to use them for soft tissue reconstruction. The first requisite for tissue regeneration is cells. Of course, there have been reports that wound healing was accelerated and whitening effect could be achieved by using only uncultured ADSCs. However, minimum amount of cells obtained from the donor site can be proliferated ex-vivo and then attached to a 3-dimensional, cell supporting structure, to replace organ or tissue transplantations. Therefore, requisites other than cells would include the cell supporting structure, or scaffold (substrate), blood supply for engraftment after the transplantation, and proteins, such as growth factors, to help differentiation and engraftment.

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1. Cell source

A cell is the most basic component of regeneration. Regeneration medicine approaches can be categorized to 1) cell therapy where the transplanted cells induce the production of materials required for human body to enhance tissue functioning and 2) forming framed tissues or an organ by mixing cells with biomaterials. These cells are mostly allogeneic cells or autogenous cells; allogeneic cells are obtained from the host after immunosuppression or in isolation from the immune system. However, this causes various side effects irrespective of treatment, making autogenous cells without such problems more preferable. A lot of studies using autogenous cells have been performed through animal tests and clinical trials, and the results are good as well. However, the use of autogenous cells sometimes needs an invasive surgery, and cells might be hard to collect when the tissue to be reconstructed is severely injured. Already differentiated somatic cells have limited proliferative activity, making it also difficult to obtain sufficient number of cells, and there is also the possibility of transformation or loss of tissue regenerating ability in the course of proliferation. In order to overcome these limitations, studies have been conducted on methods to secure an alternative source of cells in large amount.



In this context, stem cells than can overcome such limitations of somatic cells are gaining much attention, with a lot of studies on the subject. Stem cells normally have self-renewal ability and are defined as nonspecific cells that can differentiate to various types of mature cells. Stem cells are categorized to embryonic stem cell, fetal stem cell and adult stem cell according to the time of occurrence, or to totipotent cell, pluripotent cell, multipotent cell and unipotent cell according to the differentiation ability.



Embryonic stem cells are recognized as effective for tissue regeneration because they are most potent in proliferation and differentiation abilities. However, cell cloning technology by means of nuclear transfer is required to obtain this cell, and this cell is known to induce teratoma when transplanted directly in the human body and still carries a great risk even when the cell was properly differentiated. The use of embryonic stem cells also carries ethical controversy due to the acquisition of ovum, manipulation of embryo and its artificial destruction. Due to these issues, adult stem cell has been studied a lot in recent years. Adult stem cells have relatively weaker proliferation and differentiation abilities than embryonic stem cells, but are easy to obtain without an ethical issue, and the possibility of easy clinical application makes it an attractive target in many studies. Adult stem cells are distributed around various tissues in the human body from the bone marrow to fat, blood, heart, nerve, muscle and skin, and a lot of efforts are still being made to isolate it from various other tissues. Recent studies are investigating stem cells collected from the fat, amniotic fluid and placenta. These cell groups have similar characteristics to embryonic stem cells but do not induce tumorigenesis in the body and do not stir an ethical issue.



Another cell source currently being actively researched is Induced Pluripotent Stem Cells (iPSCs). Shinya Yamanaka at Kyoto University and John Gurdon at the University of Cambridge jointly received 2012 Novel prize for Physiology or Medicine for the study of iPSCs. iPSCs refer to cells induced to have pluripotency by artificial dedifferentiation of differentiated cells without pluripotency, and is also called dedifferentated pluripotent stem cells.



First introduced in 2006, this method transfers Oct4, Sox2, c-Myc and Klf4 genes, which are the main transcription elements of the already differentiated normal cells, by reprogramming cells to overexpress these genes to make pluripotent stem cells. According to a follow-up study, iPSCs were found to have the characteristics of embryonic stem cells, and since first induced in skin fibroblast cells of mice, iPSCs were successfully induced in human somatic cells as well. iPSCs are available for individualized production and can be used for drug screening, disease studies and reconstruction of injured tissues. However, the success rate of current reprogramming is only about 1-2% and requires more time and studies to commercialize them for clinical application.

2. Biomaterials for tissue regeneration

Biomaterials are essential for application of regeneration medicine, along with cells. Biomaterials for regeneration medicine can be used alone or in combination with cells for various purposes. When used alone, biomaterials are used for generally for restoring injured areas by filling or linking defective tissues or for normalizing the function of tissues by inducing their regeneration. On the other hand, when biomaterials are used in combination with cells, the biomaterials work as a medium to deliver cells into the body. Biomaterials for transplantation are composed of ingredients than can facilitate cell adherence and proliferation and has porous structure for smooth cell migration, angiogenesis and supply of nutrition. Such biomaterials should also be helpful for cell culture and be able to control cell phenotype without cell function or gene modification. They also have to provide a supporting role of the mechanical of physical strength required for a particular tissue and should be able to disintegrate spontaneously after a certain period of time, without leaving a foreign substance in the body. The ideal biomaterials for transplantation in the body should have confirmed biological suitability and safety, should be harmonized well with the surrounding tissues once transplanted inside the body, should not induce an inflammatory response in case of synthetic material, and should interact easily with the host. A number of biomaterials have been used so far for regeneration medicine studies, and various materials are currently being synthesized or produced for individual study purposes. Biomaterials can be broadly divided in to synthetic polymers and natural polymers. Studies using absorbable synthetic polymer compounds have been actively performed recently. Synthetic polymer compounds have several merits. They are capable of being produced in various forms, easy to handle, and available for mass production at a low cost. In addition, the raw materials to make them are easy to obtain.



On the other hand, their biosynthesis and tissue affinity are lower than the natural polymers. Along with the use of absorbable polymer compounds, studies on treating in-vivo tissues or organs to eliminate cells and components of the tissue without structural damage has been actively performed to use it as a supporting structure. A supporting structure from natural tissue has similar property to the in-vivo tissues, high affinity to cells and tissues, and contains factors that are helpful for regeneration, which is why it is used for various experiments and clinical studies.



Recent studies on biomaterials are more focused on developing an intelligent supporting structure that plays a more proactive role. Previous studies expected the supporting structure simply to deliver cells and to form a 3-dimentional structure when used in combination with cells. Recently, however, efforts have been made to give the biomaterial and supporting structure the ability to facilitate regeneration through a highly-advanced manipulation.



Such an additional function may be set differently for various purposes of a study, and can induce the production of regulators, which stimulate differentiation and proliferation of cells. Furthermore, there are also studies focused on transplanting a functional supporting structure alone in the body to activate autogenous stem cells of the host and to facilitate tissue regeneration by inducing the activated autogenous stem cells to move into the transplanted supporting structure. Another possibility has been suggested that proper manipulation of the supporting structure alone can procure and differentiate cells necessary for tissue regeneration. Such a method would be able to exclude cumbersome tissue collection, ex-vivo culture and proliferation of cells in the process of tissue regeneration and may reduce sources and time required for cell culture.



3. Vascularization of regenerated tissues

Transplanted cells and supporting structure in the body can survive by receiving nutrition and oxygen from blood vessels; therefore, rapid vascularization is essential. In order for cells to survive for a long period of time in a sizable supporting structure produced as a 3-dimentional form, oxygen and nutrition should be able to be delivered everywhere throughout the supporting structure by sufficient vascularization. To achieve this purpose, studies often use angiogenesis factor, such as Vascular Endothelial Growth Factor (VEGF). Such factors are known to stimulate neovascularization, and recent studies reported that these factors can form relatively large tissues by synergistic effect when combined with endothelial cells. Another approach is to insert genes that can produce angiogenesis factors for the same consequence, although this method may not be easy for clinical application. However, various combinations of such methods are continuously attempted. Another method to induce neovascularization is to optimize the synthesis of biomaterials and the microstructure of the supporting structure. A supporting structure with pores of proper size helps the provision of nutrition and oxygen, thereby facilitating neovascularization and infiltration.



Recently, a lot of studies are investigating the technology to make a supporting structure with microvascular networks for endothelial cells to grow on and methods to use organs or blood vessels as a supporting structure. However, such methods are still limited for forming large tissues required for actual clinical application, because biological methods using angiogenesis factors may temporarily stimulate angiogenesis but cannot maintain the effect continuously. To overcome such limitations, recently there have been efforts to prolong the lifetime of cells contained in the supporting structure, with the purpose of providing elements required for cell survival continuously until angiogenesis occurs.



One example is to insert a particulate that generates oxygen inside the supporting structure or biomaterial, where it can release oxygen continuously to maintain cell survival. Development and application of various advanced technologies are expected to accelerate the research processes of regeneration medicine and its clinical application.



4. Enhanced function of cells and supporting structures

The objective of regeneration medicine is to restore injured tissues rapidly. Therefore, more attempts are focused on transplanting tissues that have almost fully matured structure and function for more rapid recovery of the injured tissue, rather than transplanting cells or tissues with the expectation of functional recovery during the follow-up. For example, treatments using regulating factors, which mediate cell to cell interactions, and growth factors are under development. Development of new technologies, such as nanotechnology, enables genetic modification to release certain factors continuously or recently more effective delivery system of growth factors.



Among the methods to mature tissue function outside the body as best as possible is bioreactor. Biomechanical factors are known to have great influence on growth, maintenance, regression and recovery of tissues. In the process of producing tissues ex-vivo, such biomechanical stimulations similar to those inside the body are essential for successfultransplantation of the tissues into the body.



Such a bioreactor typically modifies the temperature, pH, oxygen, carbon dioxide, various nutrition, metabolites, and other regulators as required for tissue or cell culture. Recently developed high-end bioreactors can automate such a regulating function, with monitoring ability, and provides more varied biomechanical environments. Biomechanical stimulations are more effective for tissue generation of the cardiovascular system, musculoskeletal system, skin and blood vessels, which require higher strength and durability in dynamic environment. Recent developments in computer engineering and the production technique of biomaterials made more detailed simulation of biomechanical environments available. This data is used for making more functional, biomimetic artificial tissues and organs through the production of a more ideal bioreactor of the environment wanted for each tissue.



The next article will look into the acellular dermal matrix, which plays a role as a template for regeneration.



References

❶ Regenerative Surgery 3rd ed. Yu Ji and Lee Il Woo. Koonja Publishing. June 10, 2010.

❷ Neligan PC, Plastic Surgery, 3rd ed, Elsevier2013,

❸ Clinical Application of Adipose DerivedStromal Cell Autograft for Wound CoverageSeo DL, Han S, Chun KW, Kim WK J KoreanSoc Plast Reconstr Surg 2008 Nov 035(06):653-658.

- To be continued -

▶ Previous Artlcle : #1. Introduction of Regenerative Surgery and Regenerative Medicine

▶ Next Artlcle : #3. Acellular Dermal Matrix

[History and Development of Cutaneous Lasers ] #2. Development of Vascular Laser I

There is a controversy regarding which has been developed first between lasers for pigmented lesions and lasers for vascular lesions. Lasers for pigmented lesions were already mentioned in papers published in 1960s, and some of them mentioned hair removal too. Alexandrite laser and dye lasers for pigmented lesions(ex; Pigmented lesion Dye Laser (PLDL)) have a longer history. However, when considering the extent of systematic development, it would be more helpful to mention the lasers for vascular lesions first for better understanding, which is also why I am mentioning it first. This is probably because the vascular lasers could achieve innovative therapeutic effects that could not be achieved earlier in some of vascular lesions. Pigmented lesions, on the other hand, can be treated with a satisfactory outcome just by electrocautery, such as Bovie, or by TCA chemical peeling, without even using a laser. It can be said that the lasers for pigmented lesions started to be developed systematically, later than the vascular lasers, from the moment when it was used for treating dermal melanosis (nevus of Ota or nevus of Ito) that were nonresponsive to conventional treatments.

When skin lasers for destroying blood vessels are arranged in the order of market release, regardless of the order of development by physicists, the order would be argon laser, dye laser, copper vapor laser, KTP and Nd:YAG, and Alexandrite laser. Dye laser can destroy blood vessels without damaging the adjacent tissues, and can be said as the most important one among others. Vascular lasers are broadly divided to those with and without the concept of Selective Photothermolysis by R. Rox Anderson. In order to destroy blood vessels selectively, the theory can be satisfied by using wavelengths, such as 418, 542 and 577nm, which can be absorbed better into oxyhemogloblin than melanin. In practice, however, the depth and the size of the target works as obstructive factors, and a number of lasers have evolved diversely, apart from these wavelengths.

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Understanding the sequence and reasons of development from the past and understanding why such changes in wavelengths and pulse duration have occurred would be helpful for better clinical application of vascular lasers. Determining the optimal vascular laser for each skin problems that are made up of blood vessels or that are treatable by destroying the blood vessels distributed throughout the lesion (such as Port wine stain, Telangiectasia, various Hemangiomas, Sebacious Hyperplasia, Verruca, Facial flushing, Rosacea, Scar, Keloid, Varicose vein, Venouslake and Stria  distensae) would be the most important basic knowledge as well.

Development of the first vascular lasers was mostly centered around Boston area in USA.. Most of the developed vascular lasers were imported into Korea, but the problem was that each laser had advantages and disadvantages, making it impossible for a clinic to deliver the best treatment for all kinds of vascular diseases. This might be also one of the reasons why dermatologists lost confidence in vascular lasers. One might think that a newly developed laser device should have a better therapeutic effect in every aspect. In practice, however, the previous device may be better suited for a specific disease or condition. Moreover, some diseases do not require a special know-how about the procedure, contributing to the present complex state of medical community where clinicians can perform laser therapies even without full understanding of skin diseases or the skin itself enough to make an accurate diagnosis. In Korea, the distribution of vascular lasers seems dwindling with time due to the issues such as side effects, efficacy and insurance coverage. Nevertheless, the development process of vascular lasers is highly important, because it can be the basic knowledge for general understanding of lasers.

SPTL-1//b 585nm 450us

It is helpful to understand the relationship among R. Rox Anderson and Horace Furumoto, OT Tan, Candela Corporation, Cynosure and Wellman Laboratory to learn about vascular lasers. Let’s find out about their roles and related history from their papers, before looking into the device itself. It is not too much to say that the early development phase was focused on the treatment of nevus flammeus (Port wine stain or Nevus Flameus)

Wellman Center for Photomedicine at MGH Harvard Medical School

Once called the Wellman Laboratory of Photomedicine, this laboratory focused on the research of light that affects human biology and development of diagnosis and treatment devices using light. The laboratory was established upon the contribution of Mr. and Mrs. Wellman. It has grown in size by John Parrish, and now R. Rox Anderson is the director of the laboratory. The Wellman Center for Photomedicine played a decisive role in the development of skin laser therapies and is still playing a central role in preliminary studies and clinical studies of various lasers, with the Beckman Laser Institute of UC Irvine, where J. Stuart Nelson is the medical director.

Horace Furumoto

After graduating Ohio State University, he participated in the development of weapons using laser. In 1970, he established Candela Corporation and worked there for 19 years as CEO. He also founded Cynosure in 1991 and worked as a CEO until September 2003.

This Japanese American man is also known as the one who developed high-power dye laser, and has laid the foundation for a number of skin lasers that are currently used. After having a conflict with investors, he resigned from 19-years of work as a CEO of Candela and founded Cynosure in 1991. He had a crucial effect on the early study of R. Rox Anderson, who established the concept of Selective Photothermolysis. However, the two men did not seem to get along very well and left only few papers or traces of working together. It is speculated that the two men worked on laser studies together at the Wellman Laboratory of Photomedicine for a certain period of time from the end of 1970s through 1980 (e.g., Effect of dye laser pulse duration on selective cutaneous vascular injury. Garden JM, Tan OT, Kerschmann R, Boll J, Furumoto H, Anderson RR,Parrish JA. J Invest Dermatol. 1986 Nov;87(5):653~7).

The reason of lasers made by Candela and Cynosure still have many similarities is probably because the two companies were founded by the same person. Being a CEO and physicist, he made creative and durable lasers, although overall completeness may be lacking in some cases because he could not receive much help from clinicians or laboratories. He died at the age of 76 on July 9, 2007. The American Society of Laser Medicine and Surgery (ASLMS) awards research projects every year in memory of him.

[Tip]

History of Dye Laser by Candela Corporation

SPTL-1p : 577nm 360us
SPTL-1a : 585nm 450us 5mm spot
SPTL-1b : 585nm 450us, 7mm spot
SPTL-2: 585nm, 590nm, 595nm, 600nm(tunable) 0.45~1.5ms true long pulse.
Sclerolaser
ScleroPlus: increased spot size
ScleroPlus HP: abbreviation of High Power, increased Max Fluence, addition of DCD
(Dynamic Cooling Device)
VBeam : 595nm, 0.45~40ms DCD, Stuttered, not True Long pulse(4 sub-pulses)
VBeam Perfecta: 8 sub-puldes

OT Tan

She is a Chinese doctor, graduated from a medical school in the UK. She is the main author of the early clinical studies about dye laser for the treatment of vascular lesions. She was once a rival dermatologist of R. Rox Anderson. After working at the laser center of Boston University, she went back to the clinic again in the mid ‘80s and has been working as a practitioner in Boston. Below listed are the representative studies that can be helpful for understanding vascular dye lasers. As you can see, her studies are in line with the development of vascular dye lasers.

1. Histologic responses of port-wine stains treated by argon, carbon dioxide, and tunable dye lasers. Apreliminary report. Tan OT, Carney JM, Margolis R,Seki Y, Boll J, Anderson RR, Parrish JA. Arch Dermatol.1986 Sep; 122(9):1016~22.
2. Tunable pulsed dye laser for the treatment of benigncutaneous vascular ectasia. Polla LL, Tan OT, GardenJM, Parrish JA. Dermatologica. 1987 ;174(1): 11~7;577nm, 360us.
3. The treatment of port-wine stains by the pulsed dyelaser. Analysis of pulse duration and long-term therapy.Garden JM, Polla LL, Tan OT. Arch Dermatol. 1988Jun; 124(6): 889-96.; 577nm, 20us or 360us.
4. Treatment of children with port-wine stains usingthe flashlamp-pulsed tunable dye laser. Tan OT,Sherwood K, Gilchrest BA. N Engl J Med. 1989 Feb 16;320(7): 416~21.; 577nm.
5. 585nm for the treatment of port-wine stains. TanOT, Morrison P, Kurban AK. Plast Reconstr Surg. 1990Dec; 86(6): 1112~7; 577nm와 585nm 비교
6. The next article will focus on the detailed history of dye lasers, including argon laser, copper vapor laser and dye laser of Candela Corporation, in chronological order.

- To be continued -

▶ Previous Artlcle : #1. Naissance of Cutaneous Laser

▶ Next Artlcle : #3. Development of Vascular Laser Ⅱ-1

[Hair Transplantation] #1. History and Basic Concepts of Hair Transplantation

Autologous hair transplantation is one of the most popular treatment choices for alopecia. However, it is not a simple procedure as it involves a surgical method. This article in the series will discuss general topics of hair transplantation. Dr. Hwang Sungjoo from ‘Dr. Hwang’s Hair Hair Clinic’, a famous hair transplantation center in Seoul, Korea, has contributed this article. Dr. Hwang is an internationally recognized hair transplantation expert and served as the president of Asian Association of Hair Restoration Surgeons (AAHRS) from 2011 to 2012. In his series of contributions, he will share helpful tips from basic concepts of hair transplantation to detailed surgical techniques that can provide practical benefits to our readers.

The history of medical hair transplantation is known to have begun with Dr. Okuda in Japan in 1939. Dr. Okuda, a dermatologist, performed hair transplantations on burn scars with a punch that he developed. His studies were published in Japan’s medical journals, however, the records of his discovery were not known outside Japan. In 2009, his grandson and Dr. Imagawa who was a friend of Dr. Hwang discovered Dr. Okuda’s clinic of 70 years ago along with the punches that he used and brought to light the historical discovery of Dr. Okuda (Figure 1).

[Figure 1. Dr. Okuda’s clinic and the punches that he developed]

It is also reported that in 1943 Japan, Dr. Tamura transplanted a single hair or two-hairs in patients with atrichia. This technique is similar to today’s hair transplant techniques. In 1953, Dr. Fujita was recorded to have performed hair transplantation using a punch in a leprosy patient.

The first doctor to use hair transplantation in male pattern alopecia was Dr. Orentreich of the US. He also used the punch to extract the follicles. This surgical method using the punch is known as Okuda-Orentreich technique. He proposed the idea of ‘donor dominance’ in his paper published in 1959. This theory posits that the transplanted hair retains its original properties from the ‘donor site’, which include the growth speed, hair cycles, texture and color, etc. This theory became a widely-accepted theory in the field of hair transplantation. However, in 2002, I proposed the theory of ‘recipient site influence’ for the first time in the world. This theory suggests that the transplanted hair adjusts or changes its speed of growth and follicle cycle, etc. according to the anatomical location and characteristics of the recipient site. Currently, this theory of recipient site influence is the more accepted theory in the science of hair transplantation (Figure 2).

[Figure 2. I transplanted scalp hair onto a calf in 1999. Ten years later, the transplanted hair showed very slow growth rate compared to the scalp hair and the maximum length did not exceed 15cm.]

In male pattern alopecia or female pattern alopecia, the transplanted hair is not lost after transplantation because the follicles in the donor site and recipient site do not share the same genes. In other words, the follicles in the forehead or crown with hair loss have genes prone to alopecia whereas the follicles in the back of the scalp do not carry these genes. This is why the transplanted follicles extracted from the back of the head do not develop alopecia. As the hairs from follicles extracted from the back of the head and transplanted in the forehead grow in the same manner as before transplantation, this may appear as if they retain the properties of the donor site. However, the hairs from different areas of the scalp have identical properties and it can also be said that the transplanted hair’s unchanged growth pattern is due to the influence of the recipient site. When transplanting follicles from the scalp onto the eyebrow or pubic hair, the growth slows down and the follicle cycle is shortened. On the contrary, transplanting the chest hair onto the scalp speeds up the growth and increases length of the hair. Thus, the theory of recipient site influence which proposes that the growth pattern of a transplanted hair is influenced by the recipient site, has more ground.

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In Korea, Mr. Jeongki Paek, a medical assistant working at the leper community in Sorokdo during the 1960s transplanted hair onto the bare eyebrows of a leprosy patient and this is known to be the earliest case of hair transplantation on records in Korea (Figure 3).

[Figure 3. Mr. Paek, Hair Transplant Forum; September/October 2000 Volume 10, Number 5]

In the beginning, he used a mini graft but gave up the method due to resulting unnatural appearance. He went on to use a tool for transplanting single hairs (Figure 4) to transplant single hair graft in the eyebrow site and performed this technique in over 3,000 leprosy patients.

[Figure 4. The hair implanter Mr. Paek used in 1969. Hair Transplant Forum: September/October 2000 Volume 10, Number 5]

Witnessing Paek’s success, a surgeon named Youngchul Choi learned the method of transplantation from Mr. Paek and improved on the original tool. This was the birth of Choi implanter, a tool still widely used today. In other countries, the slit method is widely used, however, Korean doctors prefer an implanter due to such history (Figure 5).

[Figure 5. Hair implanter]

The slit method, dominant in Western countries, is performed with a doctor creating a slit with a needle or blade in the anesthetized recipient site and the assistant planting the extracted follicles. This assistant-dependent method is physically less demanding for the doctor. Hair transplant using the implanter, on the other hand, is a more doctor-dependent procedure requiring the doctor to do most work.

In the early days of hair transplantation, a 3~4mm punch was used which evolved into mini graft method transplanting 4-6 hairs into 1.5~2mm punctures and this mini graft method was used upto the 1990s. Micro graft followed where 1-2 follicles were grafted onto the recipient site. This method does not use intact follicular units but divides the hairs, potentially damaging the follicle in the process. In 1988, Dr. Limmer of the US introduced the first follicular unit transplantation (FUT) method where the follicle is divided into a single, two- or three hair units using the microscope (Figure 6). Since the 2000s, FUT has established itself as the prominent hair transplant method all over the world.

[Figure 6. Punch Graft, MINI Graft, Follicular Unit Graft]

Follicular Unit Transplantation is called a few different terms in the Korean language. A single, two or three hairs grow together from a single follicle and as the transplantation preserves this follicular unit, the most valid term for this procedure may be ‘pore unit hair transplantation’ (Figure 7).

[Figure 7. Before pore unit hair transplantation (left) and one year after (right)]

Recently, follicular unit extraction (FUE) method using a 0.8~1.2mm punch and not the traditional 3~4mm punch is applied for follicle extraction from the donor site. This may benefit western patients as they tend to have short and thin follicles, however, follicles of Koreans are long and thick. Thus FUE carries the risk of transection and greatly compromises the graft survival, making it less suitable in Asians.

The International Society of Hair Restoration Surgery (ISHRS, www.ishrs.org) is a globally recognized association on hair restoration. It was established in 1993 and currently has 798 members from 63 countries. ISHRS conferences mainly feature procedures involving western patients and may not be applicable to Asians who have very different skin characteristics. This called for a new conference that focused on Asian patients. In 2010, Asian Association of Hair Restoration Surgeons (AAHRS, www.aahrs.asia) was established and the first conference was successfully held in Bangkok, Thailand in June 2011. I was inaugurated as the second president of AAHRS at the first conference in Bangkok and the second annual conference was held in Seoul in 2012.

-To be continued-

[Scar Treatment] #1. Definition and Pathological Study of Scars

Scars are treated by various methods including surgery, laser, drugs or external preparations. Recently, laser treatment becomes popular. Before laser scar treatment, general understanding about scars are absolutely necessary. This series attempts to deliver general information about scars in addition to the definition and pathological analysis of scars. The author is Professor Kim Won-serk at the Department of Dermatology of Kangbuk Samsung Hospital, Sungkyunkwan University. Prof. Kim is actively participating in clinical and academic activities of various fields including dermatology for scar treatment.

1. Definition of scar

Scar is considered as a wrong process of wound healing, which occurs mainly in human and some mammals. Scars are visibly distinct from the surrounding skin by their contour, color and texture and may accompany volume changes, such as in case of atrophy and protrusion. A scar, in a broad sense, includes depressing scar made by acne or trauma, scars accompanying difference only in the color or texture as stretch marks, hypertrophic scar made by protuberance of postoperative suture site or burned site, and keloid which grows continuous like a tumor.

[Figure 1. Classification of scar]

2. Epidemiological study of scars

1) Keloid: Keloid is known to develop only in humans, but there have been reports of keloid cases in some mammals, including horse, cow, dog, etc. Keloid is most frequent in black people, followed by Asians and white people. The incidence is not different between men and women, and occurs often in younger people. Postmenopausal reduction of lesions has been observed in women.



2) Hypertrophic scar: Accurate incidence is not known, but hypertrophic scar is generally more common than keloids and are mostly recovered spontaneously unlike keloids. As with keloids, hypertrophic scar is frequent in the order of black people, Asians and then white people.

[Figure 2. Clinical patterns of various scars (keloid/mature scare/atrophic scar/immature scare/hypertrophic scar)]

3. Causes of scarring

1) Genetic: Generic factors are considered to be involved mostly with keloids. Genetic factors, such as HLA-B14 and 21, have been studied for their involvement.



2) Trauma: A variety of skin stimulus, including surgery, injection, piercing and burn, may be important causes of scarring.



3) Surface tension: In addition to natural surface tension arising from skin defect, difference in body parts also makes some parts more easily affected than other body parts. For example, scars or keloids are bigger and more frequent at sites with major muscle movements (arms and legs) and sites where breathing occurs (front chest).



4) Hormonal effect: Considering the fact that scarring occurs less frequently before puberty and after menopause, it is suspected that sex hormone might have some association with scarring, although the exact association has not been studied a lot.



5) Immunologic cause: Immunology is not considered as an important cause of scarring, but there have been reports that higher serum level of immunoglobulin E was associated with higher frequency of scarring and that allergic people are more likely to develop keloids.



6) Melanin pigment cells: This hypothesis comes from frequent scarring in black people and less frequent scarring in areas without melanin pigment cells.



7) Association of collagen diseases: Patients with a congenital abnormality in collagen metabolism may have excess or lack of scarring.

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4. Pathological study of scars

1) Scars are mostly confined to the dermis but may extend to the subcutaneous layer in rare cases. The most significant histopathological characteristic of a scar, compared to normal tissues, is the absence of skin appendages (hair and glands)



2) Pathological differences may be observed between an early lesion and an advanced lesion; early lesions show infiltration of inflammatory cells, vasodilation and vascularization, while advanced scars show reduced cell density, deposition of firm and thick collagens, and loss of blood vessels. These pathological features well matched with red color of early scars and white color of mature scars.



3) Scar tissues have thick epidermis and flattening of epidermal ridge.



4) Collagens in scar tissues have increased collagen synthesis than in normal dermis; among others type 1 and type 3 collagens are increased, while type 4 and type 5 are decreased. It has been reported that type 1 collagen increases by 95% in keloids.

5) In the course of wound healing, the most important growth factors for collagen synthesis and contraction in fibroblast are TGF-beta and PDGF, which are increased in scar tissues.



6) Hypoxic condition within tissues is thought as an important triggering factor of scarring. This might be associated with frequent vascular occlusion in scar tissues.



7) Accumulation of immunoglobulin G, A and M is observed often in scar tissues, and there have been reports of autoimmune anti-fibroblast antibodies detected in keloids.



8) A lot of mast cells are detected in scar tissues and, as mentioned earlier, keloid patients often have allergic symptoms. Mast cells distributed between collagen fibers stimulate immunoglobulin E and releases a large number of growth factors, histamine and serotonin, which affects the synthesis of components in the dermis.

[Figure 3. Pathological finding of a keloid]

[Figure 4. Pathological finding of a hypertrophic scar]

References

1. Berman B, Zell D. The Medical Treatment of Scarring, In: Arndt KA, editors. Scar Revision. 1st ED. Philadelphia: Elsevier Saunders, 2006:17-43

2. Decker RH, Wilson LD. Effect of Radiation on Wound Healing and the Treatment of Scarring, In: Arndt KA, editors. Scar Revision. 1st ED. Philadelphia: Elsevier Saunders, 2006:89-103

3. Al-Attar A, Mess S, Thomassen JM, Kauffman CL, Davision SP. Keloid Pathogenesis and Treatment. Plast Reconstr Surg 2006; 117:286-300

- To be continued-

▶ Next Artlcle : #2. Recent Trend of Scar Treatment

[Understanding Images by Filler and Cases Studies] #1. Summary of Images by Filler

This article in the series discusses Images by Filler first developed by Dr. Jeon of Banobagi Skin Clinic in Seoul, Korea. Images by filler procedure considers the entirety of the facial image rather than focusing on a particular facial feature. In this series, Dr. Jeon will discuss important details of this new procedure in the order of the summary of images by filler, selection of the patient and filler, patients most and least likely to benefit from images by filler, method of treatment, side effects and precautions with the procedure, etc. Moreover, he will also provide various case studies to give a clearer picture of images by filler procedure to our readers. Images by filler procedure does not focus on particular facial area and its success depends greatly on the doctor’s creativity. This procedure promises to be new and successful field in filler treatment.

Not too long ago, I came across a news report on a Korean broadcasting website, KBS, that Korea had the highest rate of plastic surgery procedures in the world with 13.5 procedures performed per one thousand people. The report also said that breast implantation was the most common procedure in the US and Brazil, rhinoplasty was prominent in Japan and China and non-incision procedures such as mole removal and botulinum toxin injection were commonly chosen in Korea. I thought it was a bit far-fetched to count mole removal as plastic surgery but it made me think again about the preference of non-incision procedures in Korea as Korea was leading the world in frequency of plastic surgery.

I first came across the filler procedure in 2004 during my career. At the time, Korean Dermatological Association mainly featured lectures on chemical peeling, or botulinum toxin and filler procedure was not as popular. However, there were a few pioneering doctors that gave innovative lectures on facial filler. They left quite an impression on me and I was inspired enough to try filler procedures following their footsteps. Most lectures on filler focused on nasolabial folds, frown lines, forehead and cheeks. That is, these lectures discussed how to fill the nasolabial folds, what type of filler to use, or which technique was the most effective. I learned a lot from these lectures but started to wonder if the fillers could be used to correct the total facial image rather than being limited to partial  site. 

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In fact, when it came to lasers, I was also harboring similar thoughts. I was losing interest in using a single laser for various effects. Rather than trying to bring different effects with a single laser, I had thought it would be more effective to have many types of lasers, each with different functions, and apply them simultaneously depending on the types of skin lesions to bring about the best overall results for the whole face, as if to fit together many pieces of a puzzle to complete the whole picture. I got this idea about two years into my private practice and it was called ‘program treatment’ at the time, the details of which are discussed below.

Using Ellipse I₂PL, brighten the overall facial tone and using Gentlase (currently, G-Max), remove hair below the nose, between and around eyebrows. Using CO₂ laser, remove milium, moles, syringoma, and verruca plana, etc. If necessary, combine the use of Er:YAG laser. Using Q-switched ruby laser, treat freckles, lentigo, and seborrheic keratosis, etc. Using the Sellas fractional Laser, tighten the pores and Vbeam to treat acne erythema and telangiectasia. Finally, using the laser toning, brighten the overall skin tone one more time. This is the so called ‘All-in-one therapy’ that I developed four years ago. This method treats all types of skin lesions in one day.

Figure 1. The Golden Section is the only point in line ab that divides line ab in a ratio of 1.618(a) to 1(b); 1(a) to 0.618(b); and 1(a) to 1.618(a+b). Revised from Clin plastic surg 38(2011) 347-377

Patients were satisfied beyond expectations. They compared the effect of the ‘All-in-one therapy’ to that of the simultaneous plastic surgery procedure of the eye, nose and facial contour. In other words, it was possible to use different types of laser at the same time to bring the drastic improvements just as with plastic surgery. Images by filler is a step forward from this All-in-one therapy.

In 2011, a Canadian plastic surgeon named Arthur Swift gave a lecture in Korea on the topic of ‘BeautiPHIcation: A Global approach to facial beauty’, based on his paper published in Clinical Plastic Surgery. In this lecture, he argued that the existent beauty, whether natural or man-made, follows the principle of the golden ratio. The golden ratio can be mathematically expressed as 1.618:1. The number 1.618 was termed ‘phi’ after the Greek sculptor Phidias who often used it in his artworks. I was very impressed with the idea of approaching the human face with the concept of ‘phi’. And I agreed with his ideas of approaching the entire face using filler and botulinum toxin, rather than focusing on limited areas. At the time, I was performing filler procedures for the entire facial image and Dr. Swift’s lecture was more than enough to convince me further of the benefit of this method. I assume those pioneering doctors who have been performing filler procedures longer than anyone must have also taken this approach. I wanted to have my own filler technique just like the All-in-one therapy and create a trend. This was how images by filler procedure came into being.

In detail, first, close history taking and consultation with the patient informs the doctor of where the patient wants to improve, correct and rejuvenate in his or her face. After taking photos, the doctor gives explanation based on the entire facial image rather than a particular area and moves on to the actual injection of filler. For example, the procedure covers at least three or all of the front cheek bones, nasolabial folds, cheeks, marionette lines, and the chin as well as the forehead, between the eyebrows, nose, palpebral arch, and mid cheek groove. The Total Filler Therapy is carried out after shaping the contour of the face with filler. This is the process of images by filler therapy.

The important facial features that determine the overall beauty of the face are forehead, eyebrows, eyes, nose, lips and the facial contour. The facial contour includes the cheek bones, cheeks and chin. Of these areas, those eligible for filler procedure are the forehead, nose, lips and facial contour. In the order of importance in terms of images by filler procedure, it would be front cheek bones, mid-cheek groove, nasolabial folds, marionette lines, chin, cheeks and forehead. However, the order of importance may differ depending on the patient’s demands and his or her facial shape.

It is important to first analyze the face with mathematical ratio before performing images by filler procedure. The most ideal ratio of the horizontal and lateral lengths of the face is 1: 1.33. The horizontal axis connects upper tragus of both sides and the lateral axis connects the trichion and gnathion (Figure. 2).

Figure 2. The most ideal ratio of the horizontal and lateral lengths of the face

When dividing the front side of the face into three sections, the upper face is from the trichion to glabella, the midface is from glabella and subnasale and the lower face is from subnasale to gnathion. The ideal ratio of the three sections in an Asian is thought to be 1: 1: 0.8. In a Caucasian, it is mostly thought to be 1: 1: 1. This ratio can of course differ depending on personal taste, however, Asians tend to view faces with a relatively smaller lower face section as youthful looking, thus, 1:1:0.8 is deemed the most ideal ratio.

Figure 3. The most ideal ratio of three sections of the face (the front)

From the side, the face may appear as the below picture (Figure 4). The distance between the stomion and gnathion are about twice as long as the distance between the subnasale and stomion.

Figure 4. The most ideal ratio of three sections of the face (the side)

There might be a few people who may think autologous fat transplantation may be better for the overall improvement of the face. The autologous fat transplantation is indeed a very effective procedure that improves the overall image of the face and may be preferred due to its lower cost compared to the filler. However, many people are also concerned with its downtime such as general anesthesia, extraction of fat, pain, edema and bruises. Another drawback of this procedure may be the rather unnatural appearance of the face. For those concerned with these aspects, images by filler may provide a better solution.

In the next article, I will discuss the type of patients most suitable for images by filler procedure and selection of the correct filler.

- To be continued -

▶ Next Artlcle : #2. Patients Appropriate for Filler and Filler Selection