Truths and Myths About Facial Danger Zones When Injecting Soft Tissue Fillers

Despite the current dip in demand for aesthetic treatments with soft tissue fillers, minimally invasive procedures remain popular and are widely accepted as alternatives to facial surgery. Compared with surgical procedures, the downtime is shorter, costs are lower, preparation time is minimal, and the aesthetic improvement is immediate—especially when soft tissue fillers are used. These benefits, however, have led to the misconceptions that filler treatments are easy to perform and that with a weekend course, anyone can become a “master injector” overnight.

The reality is different, as a volume touch-up or rhytids treatment can result in the patient losing eyesight during the injection if it is not performed properly. These stories are horrifying, but real. They occur more often than reported in literature and they can make injectors question their career choices. Understanding that a single adverse event can substantially influence or even end a career should make every injector rethink their priorities during soft tissue filler injections. Safety should come first and be prioritized higher than the aesthetic outcome. Clinicians familiar with complications know the importance of hyaluronidase (for hyaluronic acid-based fillers) and following adverse event protocols.

The pathophysiology of filler complications remains poorly understood, but the leading theory is the “mechanical” explanation. Filler gains access to the arterial blood stream and obstructs the arterial blood flow toward the consecutive soft tissues. If the filler reaches the ophthalmic artery circulation, then the respective structures receive less oxygen and nutrients, resulting in functional and structural tissue loss. This leads to ophthalmoplegia and blindness. Therefore, soft tissue filler injectors are playing “hide and seek” with the facial arterial vasculature to avoid depositing the product near arteries. The rule is that any amount of filler product inside an artery that is greater than zero can cause serious adverse events. It is better to avoid getting anywhere close to an artery.

To accomplish that and play “hide and seek,” one needs to know where the artery is. In the jawline, where facial arteries are deep, injections should be superficial. In the nose, where the vessels are superficial, injections should be deep. However, facial arterial vasculature does not follow consistent rules. Anatomical variation is substantial—the left side of the face does not mirror the arterial pathway of the right. For example, the angular artery is not deep in an estimated 30% of pyriform fossa cases.¹

Therefore, injectors should not rely solely on textbooks or dissection courses. Instead, they should anticipate variability and use layered safeguards including:

• Facial ultrasound for facial pre-scanning
• Pre-injection aspiration
• A steady, nonmobile needle
• Small bolus injections

While helpful, these precautions do not guarantee absolute safety. Recent literature includes a ranking on which facial regions most frequently result in irreversible blindness when injected with fillers:²

1. The nose when performing liquid rhinoplasty procedures. Injectors should remain midline and deep while using a 22G cannula. This procedure should not be done on patients with history of surgical rhinoplasty.

2. The forehead when performing frontal hollowing treatments. Injectors should use a 22G cannula instead of a needle. It is important to stay deep and to not inject superficially. The treatment area should be accessed laterally and the injector should move horizontally. Injectors should not inject from cranial to caudal and they should inject antegrade, not retrograde, for hydro dissection purposes and numbing the periosteum.

3. The glabella for correction of vertical glabellar lines. Stay intradermal, using a small needle rather than a cannula. Injectors should begin the treatment perpendicular to the rhytid. Do not inject along the long axis of the rhytid. Applying the blenching technique is important.

4. The nasolabial fold for age-related corrections. Start the treatment algorithm in the temple or upper middle face, treat the fold deep at the pyriform fossa, and pre-aspirate for at least 7 to 10 seconds. Use a 27G needle in a direct periosteal approach with a maximum 0.4cc of product. If the fold is treated superficially, inject intradermally and use a perpendicular intra-dermal approach to bridge the gap. This is called the Fern Pattern Technique.3 Do not use a needle along the long axis of the fold and remember the artery is everywhere.

These tips include the most important safeguards that injectors can implement to increase safety. Anatomic knowledge, technical skills, an understanding of product rheology, and mastering dexterity are crucial. Ultrasound imaging should be used when possible because it contributes to achieving safer outcomes. The goal is always improved safety and better patient care.

1. Gelezhe P, Gombolevskiy V, Morozov S, Melnikov DV, Korb TA, Aleshina OO, Frank K, Gotkin RH, Green JB, Cotofana S. Three-dimensional description of the angular artery in the nasolabial fold. Aesthet Surg J. 2021;41(6):697-704. doi: 10.1093/asj/sjaa152.

2. Doyon VC, Liu C, Fitzgerald R, et al. Update on blindness from filler: review of prognostic factors, management approaches, and a century of published cases. Aesthet Surg J. 2024;44(10):1091-1104. https://doi.org/10.1093/asj/sjae091

3. van Eijk T, Braun M. A novel method to inject hyaluronic acid: the Fern Pattern Technique. J Drugs Dermatol. 2007;6(8):805-8.