How Have Lifting Devices Evolved? (The Evolution of EBD V)
The full text of my column published in the October 2024 issue of D&PS.
A 2011 American Society for Aesthetic Plastic Surgery survey found that patients seeking aesthetic procedures chose treatment according to the following criteria.
- The practitioner's skill
- How long the result lasts
- Treatment cost
- How noninvasive it is, with less invasive options preferred
- The doctor's explanation and recommendation
Noninvasive treatment has become so established in aesthetic medicine that the degree of invasiveness is itself a major selection criterion.
Why did devices such as Ultherapy and Shurink become popular in Korea first?
In the 2010s, HIFU gained enormous popularity in Korea, led by Merz's Ultherapy and Classys's Shurink. Treatments that succeeded in Korea increasingly went on to shape international trends. Before Ultherapy, fractional photothermolysis and the Fraxel devices based on it had become hugely popular for nonsurgical scar treatment. Monopolar RF devices such as Thermage and Oligio also found a large Korean audience for nonsurgical facial lifting. A story even circulated that an American laser-company executive thought Gangnam was a country rather than a Seoul district. Seoul, and Gangnam in particular, had become one of the world's largest concentrations of aesthetic clinics.
Reliant, now Solta Medical, entered the laser market relatively late but succeeded in Korea with the Fraxel series in 2007–2008, using that success to build its international presence. Nonablative laser treatment of acne and other scars, exemplified by Fraxel, became a major treatment category. Ultherapy likewise used its Korean success as a springboard for rapid growth in the US and China before its acquisition by Merz.
Figure 1. Classys holds seminars and attends conferences internationally, extending the reach of Korean aesthetic medicine.
Figure 2. Wontech has introduced successive Oligio models to expand its share of the 6.78 MHz monopolar RF market.
As HIFU took off, Korea also became the starting point for the trend in absorbable PDO thread lifts. Over time, this helped set the stage for worldwide interest in facial lifting with polymer-based materials such as PDLLA, PLLA, and CaHA.
The current global enthusiasm for Korean aesthetics recalls the fashion for Goryeo culture in the capital of the Yuan dynasty, the empire that first linked Europe and Asia. Korean laser manufacturers have also gained standing. Cynosure, once a rival to Solta Medical for leadership among US laser companies, was recently acquired by Korea's Lutronic and relaunched as Cynosure Lutronic.
Why did lifting treatments flourish in Korea?
The Korean Wave was a major part of the changes of the 2010s. As Korean television and K-pop spread, Korean faces seemed to gain a reputation for looking younger than Western faces and more polished than those of Southeast Asia or China. Interest in Korean appearance grew accordingly. Koreans tend to adopt new trends quickly, as the rapid spread of high-speed wired and wireless networks demonstrates. Aesthetic medicine developed in a similar way, from facial surgery to extensive use of medical devices, achieving an international reputation. Korea has sometimes been called a nation of “digital guinea pigs” because new IT products are often tested here first, and this role appears to have had a counterpart in aesthetic medicine.
After falling behind in modernization and enduring more than a century of hardship, Korea rose from one of the world's poorest countries toward the ranks of the ten largest economies. Experts often point to diligence and manual skill as reasons. Koreans' chopstick dexterity is sometimes illustrated by children deftly picking up tiny beans, a skill regarded as particularly precise even alongside Japan and China, which share the chopstick tradition.
In 2016, a crumpled piece of gold foil tangled in mud was found at Donggung Palace and Wolji Pond in Gyeongju. Its surface was densely engraved with flowers and birds: a miniature flower-and-bird design. The paired-bird and floral motif was fashionable in eighth-century Unified Silla, matching the period when the buildings were used. The foil weighed only about 0.3 g. Advanced refining produced 99.99% pure gold, flattened to 0.04 mm. Flowers and birds were engraved with lines thinner than a hair, under 0.05 mm wide, separated by less than 0.1 mm. Two turtledoves less than 1 cm in size are detailed enough to distinguish male from female. This work occupies a sheet only a little over 3 cm across and represents an extraordinary achievement of Silla metalwork. Craftspeople today are said to be unable to reproduce the technique used 1,300 years ago. Perhaps such manual skill contributes to the reputation of Korean physicians in a field where a 1% difference can affect the outcome.
Figure 3. An artifact demonstrating the remarkable craftsmanship of Unified Silla 1,300 years ago. Without microscopes, artisans engraved hair-fine lines under 0.5 mm using techniques said to remain unreproducible today.
The greatest driver of Korea's aesthetic-medicine boom, however, is the strong interest in appearance. Despite a population of only around 50 million, Korea ranks first in men's cosmetics sales, reflecting men's interest in skin as well. Unlike makeup traditions in Japan or China, Korean makeup has long emphasized a seemingly bare face. Attention to the skin itself has deep roots.
What role does collagen play in loss of firmness?
If one substance defines skin, it is collagen: a polymer with a hydrogen-bonded triple helix. Collagen forms the structural framework of the extracellular matrix (ECM) in animal tissues, much as cellulose does in plants. Repeating glycine, proline, and hydroxyproline sequences form a triple helix, which assembles into collagen fibrils and then fibers to create the skin's basic structure. Collagen molecules form when G-X-Y repeats undergo trimerization in the endoplasmic reticulum (ER). After the triple helix leaves the ER, enzymes process procollagen, followed by collagen cross-linking.
Figure 4. Collagen fibers, collagen fibrils, and collagen molecules.
Figure 5. Collagen molecular structure. Source: https://scienceon.kisti.re.kr/commons/util/originalView.do?cn=TRKO202000002637&dbt=TRKO&rn=&page=3&keyword=undefined.
Fibroblasts produce collagen in the skin. Research into the proteins involved in this process has identified heat shock proteins (HSPs). HSP expression is therefore an important marker when assessing treatments such as monopolar RF that aim to stimulate collagen synthesis. Collagen quantity also depends on matrix metalloproteinases (MMPs), which break it down. Total dermal collagen reflects production by fibroblasts minus degradation by MMPs. UV exposure activates genes for collagen-degrading enzymes including MMP-1, MMP-3, MMP-9, and MMP-12. The transcription factor activator protein-1 (AP-1) regulates their expression, accelerating collagen breakdown and skin aging.
Figure 6. Collagen structure and intracellular synthesis. Model of cuticle collagen biogenesis. Source: WormBook: The Online Review of C. elegans Biology.
UV activates the mitogen-activated protein (MAP) kinase pathway, including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 kinase. Increased MAP kinase phosphorylates c-Jun, which combines with c-Fos to form AP-1. These events matter in intrinsic aging as well as photoaging. Aged skin expresses more c-Jun and consequently has greater AP-1 activity. Antioxidants such as green-tea polyphenols and vitamins C and E remove reactive oxygen species and inhibit MMPs, offering a way to address contributors to skin aging.
How does RF heat increase collagen?
Skin accounts for 15% of body weight and is composed predominantly of type I and III collagen. Type I makes up 80–85% of dermal collagen; type III, found in the papillary dermis, accounts for 10–15%. With age, soluble collagen decreases and insoluble collagen increases as stable multichain cross-linking rises, reducing elasticity.
Reduced fibroblast function lowers new collagen production, while increased collagen-degrading enzymes also reduce dermal collagen. Turnover falls, fibers thicken, bundles become disorganized, and the dermis thins. The epidermis also thins and rete ridges disappear. The ratio of type I to type III collagen falls, with a particularly marked decline in type I. Early signs therefore include reduced elasticity and thickness, more wrinkles, and dehydration. Melanocyte activity, by contrast, increases.
Collagen, central to firmness, begins to decline in the late 20s and falls more rapidly in the late 30s and 40s. Its large molecular size prevents intact collagen from passing through the digestive or skin barrier when taken orally or applied topically. Skin collagen therefore depends on the activity of collagen-producing cells and collagen-degrading enzymes. Retinol, widely promoted in anti-wrinkle skincare, inhibits MMPs to limit breakdown and help prevent wrinkles. High concentrations are irritating, however, limiting the effective amounts that can be used in cosmetics. Collagen-producing cell activity is linked to HSPs. Baseline HSP production peaks in the 20s and then declines, alongside collagen. As soluble collagen falls and insoluble collagen rises with age, addressing laxity first requires collagen contraction.
The smallest collagen molecule consists of three helically intertwined polypeptide chains. These assemble into fibrils 50–300 nm thick and then fibers 2–8 μm thick. Covalent cross-links between chains provide tensile strength and rigidity. Heating collagen to a certain level leaves the helical polypeptide chains intact while breaking covalent cross-links, allowing molecular movement and heat-induced shrinkage. Collagen can shrink to one-third of its original size, even at temperatures compatible with tissue survival. Because the response follows the temperature rise immediately, it can be seen during laser treatment.
The precise temperature required for collagen contraction remains uncertain, but maximal contraction occurs at approximately 65–75°C. Immediate thermal shrinkage therefore needs relatively high temperatures. Remodeling (the production of procollagen and new collagen after damage) can occur at lower temperatures. Tightening has been described at only around 48–50°C in the lower dermis. The exact temperatures for shrinkage and remodeling need further study. Remodeling is particularly active during the first 3 months of wound healing but continues to some extent after a year; some research reports activity even after 10 years.
How do monopolar RF, near-infrared light, and HIFU address collagen loss, a hallmark of aging skin? Each aims to stimulate neocollagenesis for firmness, tightening, tone, and lift. Monopolar RF raises dermal temperature to around 55°C. In a 1 MHz device, alternating current moves tissue ions back and forth between positive and negative poles one million times per second, generating a form of frictional heat. Treatment uses that heat to alter tissue.
Thermal denaturation breaks intermolecular hydrogen bonds, converting the triple helix to a random coil. Heat-stable cross-links remain, increasing the rubber-elastic behavior of the collagen polymer. This structural change encourages new collagen formation. With monopolar or other RF, heat-labile bonds break while heat-stable bonds persist, allowing the helix to unwind and the molecule to shorten. Electron microscopy shows thicker fibrils, loss of distinct borders, and partial fusion between fibrils. RF devices use this thermal stimulus to increase dermal collagen that has declined with age.
(To be continued in the next issue)
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