Beware What You Inject: Complications of Injectables—Dermal Fillers

INTRODUCTION

Soft tissue augmentation is steadily increasing with the aging of baby boomers in the population, mainly because it is of low cost, has instant results, and is relatively safe. Dermal fillers rank second among the top five nonsurgical cosmetic procedures, behind botulinum toxin injections.[1] According to American Society for Dermatologic Surgery survey, interest in cosmetic procedures continues to rise and these procedures continue to grow with demand, and that there has been a significant (16%) increase in the hyaluronic acid (HA) filler in 2016. As a result, there is a surge in the popularity of dermal fillers to address the signs of aging. The market is flooded with more than 100 products, and dermal fillers are currently being used by several practitioners other than dermatologists and plastic surgeons. With an increase of soft tissue augmentation procedures in the current scenario, the number of complications is also likely to increase. A thorough knowledge of anatomy, the different properties of the available filler substances, and injection techniques are essential to prevent complications of the filler. It is also necessary to detect complications early and manage them effectively to minimize adverse effects and improve patient outcomes.

There is an increase in soft tissue augmentation simply because of increased public awareness, simplicity of the procedure, and high patient satisfaction rates. This has led to a proportional increase in the number of complications.

All dermal fillers and filler procedures can lead to complications, which may be related to one of the following.

1. Product-related: Permanent non-resorbable products, antigenic nature of the material

2. Physician-related: Lack of knowledge, insufficient experience

3. Host-related: Altered host defense mechanism

Hence, it is important to be aware of all the above considerations to avoid or minimize complications.

BEWARE OF PRODUCT

A simple working classification of a product in view of complications would be as follows:

1. Nonpermanent and biodegradable

2. Semipermanent and biodegradable

3. Permanent and reversible

4. Permanent and nonreversible

Fillers are classified into three major classes based on their longevity in the tissues, which in turn depends on its structure and composition.

• Temporary lasts less than 18 months

• Semipermanent lasts greater than 18 months

• Permanent lasts longer than 24 months

It is generally believed that permanent fillers are nonbiodegradable and nonreversible, and therefore complications with the inflammatory process are more likely to occur with permanent fillers.[2]

Fillers are classified based on the histologic reaction as “volumateurs” with little cellular response and “stimulateurs” with strong cellular reaction.[3] A knowledge of this property of the filler substance may serve as a guide in predicting later inflammation or granuloma formation.

Understanding the biology of the fillers will help to avoid filler complications [Figure 1]. The HAs properties vary in terms of cross-linking, gel particle size, and their concentration. Extensive cross-linking is thought to increase longevity as they are more resistant to degradation by native hyaluronidase. Similarly, large particle size of gel has less total area that is subject to attack by the body and is more likely to resist degradation by hyaluronidase. But large particle size and increased concentration increase the hydrophilic nature of the product, leading to more tissue swelling after the procedure. Increased concentration, large particle size, and greater cross-linking increase the longevity of the product and theoretically increase the possibility of adverse reactions.

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Figure 1

Characteristics of dermal filler. HA: hyaluronic acid

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HISTORY AND PHYSICAL EXAMINATION

A history to assess physical and mental health, drug intake, and history of surgery or previous fillers in the area to be treated is important to avoid complications.

KNOW THE ANATOMY

A thorough knowledge of the anatomy of the skin and vasculature in the treatment area is necessary for the following [Figure 2]:

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Figure 2

Arteries of the face

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1. For proper placement of filler material to avoid lumps, bumps, or Tyndall effect

2. To avoid inadvertent placement into vessels, which could lead to necrosis, blindness, and other similar vascular accidents

3. To increase longevity of the product as they stay longer when injected in the recommended depth

SKIN THICKNESS

Injecting in the correct plane is important for best results. It is important to know the differences in skin thickness in different parts of the face [Figure 3]. The thickness of the facial dermis varies between 0.4mm in lids and 1.2mm in forehead and cheeks. The outer diameter of 26-G needle can be used as a rough gauge to guide the depth of injection as it measures 0.45mm, which is half the thickness of the dermis, or conversely the facial dermis is only about twice as thick as 26-G needle. So for a proper intradermal injection, the needle should be inserted at approximately 10° angle and one-needle diameter deeper. For injection into mid-dermis to treat moderate-to-deep folds, the needle should be inserted at an angle of 30°–40°, and for injection into deep dermis or supraperiosteal region to treat deeper folds, the needle should be directed at an angle of 45°–90°.

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Figure 3

Thickness of dermis in different areas of the face

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BEWARE OF VASCULATURE

Vascular compromise can occur because of inadvertent injections into certain vessels or as a result of external compression due to pressure from the injected material.

The areas prone for embolization leading to blindness are the nose, nasolabial fold (NLF), forehead, and glabella, whereas the areas prone for necrosis are glabella, tip of nose, and lips.

BEWARE OF TECHNIQUE

Dermal fillers may be injected using a needle or cannula based on the experience and comfort of the injector as both have their own advantages and disadvantages. In general, fillers should be injected slowly after aspiration, and the delivery of material should be in small volumes per pass and with least amount of pressure.[4] The use of small-caliber needles slows the speed of injection, and the use of blunt cannulas in high-risk regions, such as glabella, nose, and NLF, reduces the risk of injury to vessels.[5]

Most important for a safe practice is a sterile workplace and strict asepsis during the technique to avoid infections.

RECOGNIZING, MANAGING, AND AVOIDING DERMAL FILLER COMPLICATIONS

Despite safety measures and safety profiles of the products, adverse events do occur. The complications may be classified based on the timing of occurrence [Table 1] and may be patient related, technique related, or injection substance related.

Table 1 Complications

EARLY COMPLICATIONS

VASCULAR COMPLICATIONS

Vascular complications occur as result of inadvertent arterial injection of filler material and could result in serious injury in the form of cutaneous necrosis, blindness, or stroke.

Tissue necrosis

Cutaneous necrosis can also occur as a result of excess material causing external vascular compression, and thereby reduced perfusion leading to scar formation.[10] An intra-arterial injection can cause mechanical obstruction and damage of endothelial cells leading to ischemic changes in the skin. The common sites of necrosis reported after filler injections are the glabella, nasal ala, and NLF area [Figure 4].

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Figure 4

Sites of injection leading to necrosis -shaded area

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Early recognition and prompt action are mandatory. Painless blanching during the procedure followed by severe pain is the first sign of injection necrosis. One should stop injecting immediately and gently massage the treated area. The ischemia is usually followed by a dusky discoloration and then a necrotic skin.

Visual impairment

Blindness occurs from filler embolism to the ophthalmic vasculature. Visual loss usually occurs immediately and is accompanied by pain in the affected eye.[11] Visual complications usually occur following injections in the glabella, nose, forehead, and periocular regions [Figure 5].

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Figure 5

Sites of injection leading to blindness

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The underlying mechanism of retinal artery occlusion is secondary to retrograde embolization from peripheral vessels into the ophthalmic artery system.

INFECTION AND BIOFILMS

Infections clinically present as warm, tender erythematous fluctuant nodule with or without systemic signs such as fever and malaise. Usually, early low-grade infections are due to Staphylococcus aureus and occur as a result of contaminated filler depots and organize into biofilms, whereas late presentation raises suspicion of atypical mycobacterial infections. Bacteria present in biofilms remain dormant for a long time and emerge from their biofilm following activation by an external triggering factor such as a minor injury or manipulation, leading to low-grade infections, granulomas, or abscesses. Risk of infection is found to be higher in human immunodeficiency virus (HIV)-positive patients.

Management

Management of infection depends on the severity of the condition [Table 2]. Clinical judgment should decide the course of action with regard to choice of antibiotic, use of hyaluronidase, and surgical intervention. For mild cases, empirical therapy with antibiotics such as ciprofloxacin, clarithromycin, and amoxicillin + clavulanic acid for 2–4 weeks is suggested.

Table 2 Recommended antibiotic regimen[15]

For abscess, incision and drainage or aspiration may help in faster resolution. If empirical antibiotic therapy fails, culture-directed therapy can be useful. Hyaluronidase may be injected to avoid further spread of infection.[9] Intralesional steroids may be injected into inflammatory nodules under antibiotic cover.

INTRACRANIAL PENETRATION

There is a potential risk of accidental intracranial penetration while performing the deep temple injection technique with direct pressure on the bone as the thickness of the bone is variable at the pterion.[16] Therefore, a good knowledge of the anatomy combined with gentle injection technique is mandatory while injecting fillers into the deep temporal fossa.

LATE COMPLICATIONS

CONCLUSION

Use of dermal fillers continues to rise in popularity, and as the use of dermal fillers increases, the adverse events are also likely to increase, and it is important to be aware of all potential complications and be prepared to treat them effectively. Familiarity with prevention, recognition, and early and effective management of complications is the key to a successful and safe filler practice.

Practical tips:

1. Choose the right patient

2. Know your product specifics well

3. Master safe injection techniques

4. Recognize early signs of complications

5. Engage in proactive management to minimize their impact

6. Appropriate timing of other cosmetic procedures to be planned and executed well

In general, most complications are avoidable if injections are administered under aseptic precautions with sound knowledge of facial anatomy and technique. Dermal fillers have a great demand for the future as more and more patients opt for nonsurgical procedures with minimal downtime and risk.