One of the most popular non-surgical cosmetic treatments worldwide is lip fillers using hyaluronic acid fillers. Injectable lip augmentation has attracted much attention on social media, but it is rare to achieve natural-looking results. The result we usually see is a distortion of the lip shape, accompanied by a diffusion phenomenon called "filler migration."
In particular, the very popular "tenting/fencing technology" (including the slightly modified "Russian lip" technology) not only carries a high risk of blood vessel blockage, but also creates an unnatural "ledge". This effect is achieved by multiple linear injections of white piping perpendicular to the edge of the lip, causing the lip shape to be flattened and distorting the lip. The filler is then traced back along the multiple "diffusion channels" created by the needle, ultimately creating an unnatural ridge in the white piping. It is somewhat misleading to call this a "clear" border.
A more "exaggerated" operation is to inject directly into the vermilion edge of the lip, causing a "shelf" or, in extreme cases, a "plateau" bulge, the so-called "duck's mouth" (see Figure 1). This convex edge, shelf-like or plateau-like bulge may appear immediately after the lip injection and be mistaken for "swelling"; or it may gradually develop from a convex edge to a shelf-like shape to a plateau-like bulge over time. The spread of filler not only creates an unsightly and offensive appearance for the lips, but also has an aging effect on the entire face (see Figure 2).
Figure 1 The filler spreads to form a plateau (A). After dissolving the filler, re-inject it using the "NLL technique" to avoid injecting directly into the vermilion edge of the lip (B).
Figure 2 Aging effect of filler diffusion. (A) Filler diffusion stretches the face forward, simulating the effect of shrinkage toward the midline during aging. (B) "NLL technology" avoids direct injection into the red edge of the lip to produce anti-aging effects.
Harris filler diffusion typing method
In order to understand the different manifestations of lip filler diffusion and explore the mechanisms behind them, a new classification system - Harris Classification of Filler Diffusion - was developed based on an observational study. Spread).
This observational study was conducted in North London from September 2019 to February 2020. The study population included 48 white women aged 22 to 63 years, most of whom attended a specialized clinic for dissolution treatment of filler diffusion (2 weeks to 12 years after injection).
The extent of filler spread is measured by palpation (hardness) and visual inspection of the filler (unnatural protrusions, paleness, grayness, or whitishness), and is further complemented by photographic evidence taken off-site. Review. For unnatural protrusions, the Ricketts E-line and the author's newly developed "V-line" (see Figure 3) are used for judgment.
Figure 3 "V line" schematic diagram. Line 1 is drawn from the columella-lip junction to the labiomental fold and extends to the edge of the mandible; Line 2 is drawn from there to the tip of the nose. V1 is a measurement of the protrusion of the lower lip and should ideally be between the two lines (should not cross line 2) and should match the protrusion of the upper lip (V2) and chin (V3).
Four types of lip filler diffusion (see Figure 4):
Type 1: No spread. The filler is placed on the lipstick side surface, such as the effect of "NLL technology" (=Nonsurgical Lip Lift).
Type 2: Ledge. Fillers create abnormal ridges in the "white" rim, often seen with tenting/fencing techniques or the "Russian lip technique".
Type 3: Shelf. Filler spreads beyond the convex edge and may appear immediately after injection or gradually.
Type 4: Plateau. At this point, the filler diffuses beyond the shelf-like area.
In most subjects, the spread of filler can be felt as a hard area separated from the surrounding soft tissue. All subjects had diffuse areas that appeared pale, gray, or whitish, clearly demarcated from natural, healthy skin.
Figure 4 Harris filler diffusion typing method. Type 1 represents no diffusion (normal), and types 2 to 4 include increasing degrees of diffusion; convex (type 2), shelf-like (type 3), and plateau-like (type 4).
It should be noted that a small number of people are born with natural convex edges (sloping rather than ridges) or a common shelf-like shape when they pout, but they usually do not have other abnormalities caused by filler diffusion (shape distortion, abnormal protrusions, depressions or Unnatural light reflection).
The Mechanism of Lip Filler Diffusion
The findings support the idea that fillers spread along the path of least resistance primarily in the subcutaneous (superficial fat) layer and are further pushed by the activity of the orbicularis oris muscle (OOM). The orbicularis oris muscle is composed of two distinct parts that meet at the vermilion border
Figure 5 The orbicularis oris muscle consists of a marginal part (A) and a peripheral part (B), which meet at the vermilion border. Diffusion occurs in the subcutaneous (superficial fat) layer (C).
The marginal part forms a continuous band from the angular oris muscle on one side to the angular ori muscle on the other side, and is mainly composed of single narrow-diameter muscle fibers that meet at the medial end and attach to the dermis of the vermilion area. The peripheral portion is the thinner, more peripheral portion of the muscle, whose fibers cross at the midline, insert into the vertebral spine on the opposite side, and are reinforced by numerous local muscle attachments. The most peripheral fibers connect to the maxilla and nasal septum above and to the mandible below. The posterior part of the peripheral part is composed of horizontal, oblique and longitudinal fibers, and the anterior part has only horizontal fibers.
The contraction of some fibers around the orbicularis oris muscle produces a lifting movement of the lips, which plays a role in facial expression and speech; it is also responsible for aggravating the formation of perioral lines. The edge fibers mainly act on the lip area covered by lipstick. These fibers press the lips against the upper teeth or turn them inward in the mouth, allowing the lips to surround the incisal and biting edges of the teeth; they are also involved in human speech, producing labial sounds.
The major part of the lip is formed by the orbicularis oris muscle, which is very close to the surface and curls in a J-shape, causing the edge to protrude causing the so-called ‘white skin roll’ of Gillies-Millard. This "white" appearance is usually less noticeable in people with darker skin tones, and this area should more accurately be called "skin piping" of the lips, or simply lip piping.
Therefore, a filler placed in the superficial area of the subcutaneous lip vermilion enters a closed system, and the contraction of the marginal portion of the orbicularis oris muscle brings it closer to the mouth. When filler is placed inside a lipstick border or lip piping, it enters an open system where the filler can spread outward along the path of least resistance and be further stimulated by the activity of the surrounding portion of the orbicularis oris muscle and its supporting muscles. Push. In this way, the convex edge (type 2) diffuses over time to form a shelf-like (type 3) and then a plateau-like (type 4).
The orbicularis oris muscle changes from a J-shape to an I-shape with age; this plays an important role in upper lip lengthening and may explain why in older patients, even when fillers are placed within the closed system of the lipstick, Greater diffusion will be found along the thinned surface layer.
Another possible mechanism for filler diffusion may involve injection into the muscle (marginal part) itself, which in turn causes the filler to work its way back to the surface and begin to spread as the associated muscle continues to contract. It is highly unlikely that the filler will spread along the muscle itself without going through the path created by the sharp (or blunt) needle; also, the filler will appear pale, indicating that the spread is occurring in the more superficial (subcutaneous) layers of the perioral area .
In fact, many other factors may also play a role, such as interference with lymphatic drainage, changes in lip shape, and different configurations of the orbicularis oris muscle. The rheological properties of the filler may also be important, particularly when placed on the lip border. Here, hydrophilic fillers may spread more easily, as do fillers with low viscosity and low cohesion.
Tenting technology
Apparently, injecting directly into the vermilion border is the main cause of filler spread. The extremely popular "tenting" (or "Russian lip") technique is probably the culprit in most cases of filler spread. It opens the closed system of the peripheral portion of the orbicularis oris muscle, exposing the filler to the open system of the surrounding portion. The needle is inserted vertically into the center of the lip piping at multiple points, which not only increases the risk of blood vessel blockage, but also creates a "diffusion channel" that allows the filler to backtrack to form the convex edge unique to this method (Type 2). Over time, the filler spreads along the superficial fat layer due to the movement of the surrounding part of the orbicularis oris muscle and the levator and depressor muscles of the lower lip (see Figure 6).
Figure 6 The "tenting technique" consists of multiple injections from the lip rim (white line) to the center to form a diffusion channel; the filler is traced back (black arrow) to form a convex edge, from which it is further pushed by the contraction of the surrounding part of the orbicularis oris muscle. squeeze (red arrow).
While no studies have documented the durability of lip fillers in their spreading position, it has been observed that fillers placed on the red side of the lip typically last about a year; the "raised edge" of type 2 lasts two years; and type 3 can Lasts 3-5 years, while Type 4 lasts 5 years or more. Fillers appear to last longer as the filler dose increases and spreads more widely.
This article uses the word "spread" instead of the commonly used "migration". The latter is mistakenly associated with a problem with filler products, but most cases are actually caused by the injection technique. It's true that the filler's rheological properties may come into play once it reaches the border of the lipstick, but where the filler ends up is determined by the injection technique, not the brand of filler. Since the filler itself cannot "migrate" on its own, using the term "diffusion" correctly places the blame on the injector, who in most cases is competent to make the decision.
NLL technology
"NLL technology" (= Nonsurgical Lip Lift) is a lip injection technique designed to replace direct injection of the vermilion border (VB = vermillion border), through linear thread, curved thread and bolus drops (bolus) injections that adapt to the lip's natural anatomy (lines, curves, and mounds) to restore its ideal natural shape and inversion. All injections are performed superficially on the vermilion side, gently pressing the soft side of the edge toward the hard side. As the lips turn upward, the philtrum shortens and the philtrum becomes indirectly clearer (see Figure 7-8).
Figure 7 Injection of 0.3 ml filler using "NLL technique"; before injection (A), after injection (B).
Figure 8 Ten steps of the "NLL technique": (A) Pill injection into the lateral labial mound (steps 1, 5, 6, 10), linear injection (steps 2, 4, 7, 9), and injection into the central labial mound Place filler (steps 4 and 9) and curvilinear injections (steps 3 and 8). (B) The "H plane" (white line) marks the ideal position of the labial mound, and the "H curve" (yellow curve) determines the optimal curvature of the lower lip relative to the chin.
The classic "NLL technique" consists of ten steps, each using no more than 0.05 ml of filler (see Figure 8). The number and sequence of these steps will vary depending on the anatomy being presented. Since the vermilion border is avoided, the filler will not migrate, so the entire treatment rarely requires more than 0.5 ml of filler. Any reputable "soft" filler (low to moderate viscosity and cohesion) can be used, and injections are best done with a sharp needle rather than a blunt needle for better control and precision.
Retraction should not be performed on this particularly delicate and delicate area of the face. The syringe cannot be fully stabilized here, so the needle may accidentally penetrate the artery during withdrawal, which in turn increases the risk of blood vessel blockage. To maximize safety, use only a small amount of product, and inject very gently, slowly, and superficially (no more than 2-3 mm below the surface), minimizing associated common adverse reactions (swelling, bruising, vascular damage, etc.) Risks are minimized.
A key point of the "NLL technique" is "tubercle shifts": "moving" or reshaping the labial mound (the most convex and reflective area) to the desired direction. For example, an injection into the lateral side of the labial mound will "displace" it laterally (a raised and reflective area), thereby widening the relevant areas of the lip (the left and right sides of the upper and lower lips). Adding filler to the inside of it will "displace" it medially, shrinking the associated lip area. Similarly, injections into the anterior or posterior portion of the labial mound can achieve anterior or posterior movement of the labial mound (and associated lip area).
Therefore, the ideal lip shape can be created by moving different labial mounds.
In many cases, the labial mound may not be easily identified, making it difficult to determine its ideal location. Although there are many methods for determining the ideal proportions of the lip, such as the golden ratio and its location (proposed by Steiner et al.), there are none that specifically address the labial mound. Labial mounds are naturally occurring soft-skin bumps that are primarily responsible for lip shape and natural light reflection; there are three on the upper lip (upper right, upper left, and center) and two on the lower lip (lower right and lower left). Draw a line from the base of the nose along the top of the philtrum to the apex of the Cupid's bow, extending across the peak of the lower labial mound (the most reflective point). Draw a midline from the base of the nose down through the peak of the central hill. If the lateral H-line is extended to the chin, then the ideal curve of the lower lip will match that of the chin; the authors refer to these curves as "H-curves" or "Harris curves" (see Figure 8) . The location of the lateral hillock of the upper lip seems to be more variable, but moving it toward the H-line should lead to a more aesthetic result.
In conclusion
In summary, common unsightly results of lip injections are often related to direct injection into the vermilion border of the lip, especially with the “tenting technique”. The spread of filler may be immediately apparent as a palpably palpable pale bump in the vermilion border or perioral area, but may progress further with the addition of more filler and/or activation of the orbicularis oris muscle. The orbicularis oris muscle consists of two parts; the marginal part and the peripheral part, both of which meet at the vermilion border. Injecting directly into the vermilion border connects the closed system of the edge to the open system of the surrounding part. The degree of filler spread can be classified according to the "Harris Classification of Filler Spread", including non-diffusion (type 1), convex edge (type 2), shelf-like (type 3) and Plateau state (type 4). The newly proposed "V line" helps measure the ideal protrusion of the lip and chin, while the "H line" and "H curve" help determine the ideal position of the lip mound and the curvature of the lower lip curve relative to the chin.
