Introduction: The Truth No One Told You, Lurking Behind the Convenience
"Blindness." "Skin necrosis."—You who are considering hyaluronic acid filler, how seriously do you take these words?
Hyaluronic acid filler, which easily gets you the ideal face. However, the numbers shown bythe real data of 8,604 peoplewho underwent that procedure are known to almost no one.
- The complications of hyaluronic acid injection that differ by site and product used, and their specific incidence data
- The truth and occurrence mechanism of irreversible major risks such as vascular occlusion, skin necrosis, and blindness
- Preventive measures to dramatically raise safety, and emergency responses using hyaluronidase and the like
"I want to become beautiful," "I want to stay youthful"—precisely because you undergo the procedure with such positive feelings, you need to be prepared for the unlikely event.
What if just a single injection could lead to a lifelong scar on your face, or an outcome that robs you of sight? Hyaluronic acid filler is not a "flawless magic wand." Based solely on scientific and medical data, this article thoroughly reveals the truth and the means to avoid it.By the time you finish reading this article, your criteria for choosing a clinic should have changed.
1. Basic Information on Hyaluronic Acid (HA) Filler and Common Side Effects
"It's safe because it's a component the body already has"—That Preconception Is Dangerous
Hyaluronic acid (HA) is a component that also exists in the body, so it tends to be considered highly safe. However, it's not that there are no complications at all. This is a point many people overlook.
HA filler contains the cross-linking agent 1,4-butanediol diglycidyl ether (BDDE) and hyaluronic-acid-related proteins, which carry an inherent risk of causing hypersensitivity reactions (Fidalgo J 2018) (Keizers P 2018). Furthermore, recent research has shown that the biocompatibility of HA declines as the number of chemical modifications (such as cross-linking) to this polysaccharide increases (Fidalgo J 2018) (Keizers P 2018).
What is happening behind the reassurance of "it's a natural component, so no problem"? It has been reported that small fragments of injected HA may cause inflammation within the tissue, inducing side effects such as erythema (redness), mild edema (swelling), hematoma, pruritus (itching), and pain (Fino P 2019) (Shi XH 2016) (Taylor SC 2009).
The Side-Effect Incidence Shown by Data on 8,604 People
So, at "what rate" do side effects actually occur?
According to meta-analysis data on a total of 8,604 patients (DeVictor et al 2021) from 37 (DeVictor et al 2021) publications on non-surgical augmentation rhinoplasty (including 23 (DeVictor et al 2021) cohort studies and 14 (DeVictor et al 2021) case reports), the overall adverse-event incidence was2.52%(DeVictor et al 2021). Of these, the most common complication was bruising at1.58%(DeVictor et al 2021), and hematoma at0.13%(DeVictor et al 2021).
Looking at the type of filler used, 28 (DeVictor et al 2021) of the 37 (DeVictor et al 2021) studies (75.67% (DeVictor et al 2021)) used HA as the primary filler. HA filler was used in 6,385 patients (DeVictor et al 2021), and 199 (DeVictor et al 2021) complications were reported (incidence3.12%(DeVictor et al 2021)).
Furthermore, in another large-scale retrospective survey of non-surgical augmentation rhinoplasty in 5,000 patients, as common intraoperative complications, bleeding exceeding the standard needle-stick volume was observed in 559 people (11.1%), and immediate bruising in 100 people (2.0%). As for the post-op course, erythema within 24 hours was35.6%and swelling was28.7%were reported in patients, and these tend to be self-limiting and improve over time.
"2–3%, then I'll be fine"—did you think that? From here is what you truly need to know.
2. The Serious Complications That Must Never Be Ignored: Vascular Occlusion, Skin Necrosis, Blindness
To those who felt reassured hearing a probability of a few percent, we'll tell you another number.The Number "0.48%" Revealed by a 5,000-Person Survey—what this means, please see below.
Vascular Occlusion and Skin Necrosis: Even Below 0.1%, It's "Not Zero"
Non-surgical hyaluronic acid injection is considered relatively safe, but rarely serious complications with catastrophic outcomes occur. In the aforementioned survey of 8,604 people (DeVictor et al 2021):
- Vascular occlusion: 30 cases (DeVictor et al 2021) (0.35%(DeVictor et al 2021))
- Vision loss (blindness): 8 cases (DeVictor et al 2021) (0.09%(DeVictor et al 2021))
- Skin necrosis: 7 cases (DeVictor et al 2021) (0.08%(DeVictor et al 2021))
- Infection: 6 cases (DeVictor et al 2021) (0.07%(DeVictor et al 2021))
"0.09%, then it's fine"—but wait. This means that of 8,604 people who had the procedure, 8 went blind. At the very moment you undergo the procedure, there is no guarantee whatsoever that you are "outside" this probability.
In particular, blindness triggered after soft-tissue filler injection into the face has attracted great attention in recent years (Beleznay K 2015) (Beleznay K 2019). This irreversible visual impairment and complications such as stroke occur when filler such as hyaluronic acid is mistakenly injected into a vessel and forms an embolus retrogradely.
Specific Cases and Course of Skin Necrosis: The Nasal Tip Is Most Common
Examining the data on 5,000 HA augmentation-rhinoplasty patients in detail, arterial occlusion appeared immediately in 24 patients (0.48%). Of the 24 vascular impairments, the breakdown by site is as follows:
- Nasal tip:16 people—the most
- Nasal dorsum:6 people
- Nasal root:2 people
"Where you inject" determines the magnitude of the risk. So, where are the particularly dangerous sites?
3. Risk Tendencies by Site and the Anatomical Characteristics of Asians
"Danger Zones"—Is the Site You Want Treated Among Them?
Complication risk also differs greatly by the facial site injected. As "danger zones" with particularly high vascular-occlusion risk,the glabella, nasal dorsum (bridge), and nasolabial foldare cited (Wu S 2017).
The popular treatment sites overlap with the high-risk areas—this is a fact you must know before undergoing the procedure.
Anatomical Characteristics of Asians: Why the Same Technique Yields Different Results
To use HA filler safely and effectively, understanding racial anatomical differences is essential. The Asian nose has characteristics such as a short nasal tip, short alar rim, and short columellar base, with a tendency for the nasal root to be flat and depressed. The dorsum is usually low, wide, and flat, and the skin of the tip and supratip has a thick dermal and subcutaneous layer.
"A physician who uses techniques developed for Westerners as-is" versus "a physician well-versed in Asian anatomical characteristics"—this difference fundamentally changes the result.
4. Preventive Measures and Treatment to Avoid and Address Vascular Occlusion
Here, we must break a certain "myth" widely believed even among physicians.
"Pull back the syringe, and if blood doesn't return, it's safe"—the reliability of this "aspiration check" is only 53%(Casabona G 2015). Can you trust a safety check that works accurately only one out of two times?
Injection Techniques to Raise Safety: Three Principles
- Extremely small-volume injection and maintaining low pressure: Slow injection of an extremely small amount—0.1 ml or less per injection, and depending on the site even less than 0.05 ml—is strongly recommended. "More volume means greater effect" is a dangerous misconception.
- Choosing the right injection layer: To minimize the risk of intravascular injection, the basic approach is to inject into the deep layer above the periosteum or perichondrium.
- Choice of instrument (needle vs. cannula): There is a view that using a blunt-tipped cannula reduces the possibility of intravascular injection compared with a sharp needle, but cases of ischemia and blindness have also been reported with cannula injection into the nose.
"Four Hours" Divides Life and Death—Emergency Rescue With Hyaluronidase
In the unlikely event that signs of vascular occlusion or skin necrosis appear, treatment as early as possible is needed.
Animal experiments have demonstrated that if hyaluronidase is injected subcutaneously within4 hours (Kim DW 2011)of the onset of vascular impairment, potential skin necrosis can be recovered from and avoided. In the aforementioned 5,000-person data, of the 24 who developed vascular occlusion:
- 14 people: spontaneously recovered through vigorous massage and application of warm compresses
- The remaining 10 people: after injecting 1,500 IU of hyaluronidase dissolved in 1 ml of saline,fully recovered
. In other words, whether the clinic keeps hyaluronidase on hand determines whether the worst-case scenario can be avoided. This is the single most important point to confirm before the procedure.
5. Long-Term Effects and HA's Collagen-Generation Effect
"86.6% Still Maintained After 2 Years"—The Benefits and Risks of Long-Term Persistence
In a study injecting HA over bone (63 patients (Mashiko T 2013), 97 sites (Mashiko T 2013)), at an average long-term follow-up of21.6 months(Mashiko T 2013),86.6%of the treated sites maintained over 50% (Mashiko T 2013) of the volume (Mashiko T 2013).
This is a major aesthetic advantage. However, at the same time, cases of delayed granulomatous reactions forming have been reported, requiring long-term attention (Alijotas-Reig 2008) (Dal Sacco 2005). "The effect lasting" means that when a problem occurs, it may also "last."
Not Merely "Plumping"—The Hidden Effect of Collagen Generation
Here, we'll tell you a positive finding about HA injection.
In a study injecting HA filler intradermally (0.7 mL (Wang F 2007) of Restylane or saline into 11 volunteers (Wang F 2007)), in biopsies at4 weeks(Wang F 2007) and13 weeks(Wang F 2007) after injection, increased generation of "type I collagen" was confirmed around the HA filler. This collagen-generation mechanism has been shown to be an indirect phenomenon in which HA "mechanically stretches" fibroblasts through water retention in the extracellular matrix (Wang F 2007).
Not only replenishing volume but also raising the quality of the skin itself—choosing the procedure after knowing this fact is the attitude of a wise patient.
Summary of This Article: Remember HA Safety Knowledge in 5 Numbers
Hyaluronic acid filler is a very effective and convenient treatment in cosmetic medicine. However, without anatomical knowledge and solid technique, it always carries the risk of serious complications. Finally, let's confirm the 5 numbers you should remember and take home today.
- 2.52%・1.58%・0.09%： HA filler carries not only mild side effects such as bruising (1.58% (DeVictor et al 2021)) but also major risks such as vascular occlusion (0.35% (DeVictor et al 2021)), skin necrosis (0.08% (DeVictor et al 2021)), and blindness (0.09% (DeVictor et al 2021)).
- 3 danger zones: The glabella, nasal dorsum, and the area around the nasolabial folds are high-risk areas for vascular occlusion (Wu S 2017).
- 53%： The reliability of aspiration confirmation is about 53% (Casabona G 2015) and must not be over-trusted. Deep injection above the periosteum and small-volume, low-pressure injection of less than 0.1 ml raise safety.
- 4 hours: If vascular occlusion is suspected, prompt treatment within 4 hours (Kim DW 2011)—such as hyaluronidase injection (1,500 IU) or massage—is the key to preventing necrosis.
- Collagen still increased after 13 weeks: HA is not merely volume replenishment; its "skin-quality improvement" effect of promoting one's own collagen generation has also been scientifically confirmed (Wang F 2007).
To obtain a safe and beautiful result, we ask you just one thing at the end—Does the clinic you're now considering keep hyaluronidase on hand? Choosing a skilled physician/clinic well-versed in the complex vascular anatomy of the face and able to perform prompt, appropriate medical treatment even for unlikely complications is more important than anything.
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About the Author
Hiromitsu Nakamura Ginza Clinic Physician
Zetith Beauty Clinic Ginza, Osaka Shinsaibashi, and Fukuoka
Has a track record of research presentations at domestic and international conferences, and is also involved in technical guidance and education across Zetith Beauty Clinic. Specializing in precise cosmetic medicine based on anatomical evidence, he pursues natural results tailored to each person's bone structure and tissue.