Potential routes for retrograde embolization to the ophthalmic vessels are shown in the figure. Of note, the facial artery lies approximately 1.5 cm lateral to the commissure. The transition of the facial artery into the angular artery ( c) and its anastomosis with the dorsal nasal artery ( d) is demonstrated. The artery becomes superficial ( b) in the upper third of the nasolabial fold and is at risk during superficial injections. With the subcutaneous tissue ( e) reflected, the facial artery ( a) is seen running in the nasolabial fold, at times within the muscle but mostly in the plane between the subcutaneous tissue and muscle. 13.3 Facial cadaver dissection highlighting details of facial artery anatomy. The facial artery has many important branches such as the inferior labial artery, superior labial artery, and lateral nasal artery. Its location is closely related to the nasolabial fold, so care must be taken when augmenting the fold. Inferiorly, the artery is located deeper and becomes more superficial nearby the alar base. The tortuous course of the facial artery is also shown.

The nasolabial danger zone is highlighted in the diagram. The nasolabial fold is the second most common injection site for tissue necrosis and the third most common site leading to visual loss. In the upper third of the nasolabial fold and superior to it, intravascular injections into the angular artery could result in ocular embolism (в–¶ Fig. Subcutaneous injections in the upper third of the nasolabial fold can lead to soft-tissue necrosis of the alar or malar regions if there is intravascular injury (в–¶ Fig. The artery becomes superficial at the upper third of the nasolabial fold and is most at risk for injury at this level (в–¶ Fig. In the lower two-thirds of the nasolabial fold, the facial artery course lies beneath the muscle or in the deeper planes above the muscle (в–¶ Fig. When injecting the nasolabial region, knowledge of the depth and course of the facial artery is paramount to prevent complications associated with intravascular injury (в–¶ Fig. Lastly, in the lower third of the nasolabial zone, the artery is either within the muscle or between the muscle and the subcutaneous tissue, so more superficial injections are recommended.ДЎ3.1 Safety Considerations in the Nasolabial Region In the middle third, the artery is located deeper, so injections should be performed intradermally or in a superficial subcutaneous plane. The artery is located within the subcutaneous tissue. In the upper third of the nasolabial zone, injections should be performed deep in a preperiosteal plane or very superficially in an intradermal plane. The key in augmenting the nasolabial fold is to stay medial to the fold to prevent inadvertent injury or injections into the adjacent vasculature. 13.1 Proper injection technique into nasolabial fold. 13.1).ДЄlways perform using gentle, low-pressure anterograde/retrograde injections with constant motion in 1 mL syringes.Дo not inject along the alar rim, alar grooves, or nasal sidewall because the vasculature is superficial in these regions.ДЇig. Use incremental deep depot injection techniques in the periapical areas (в–¶ Fig. Near the alar base, inject either intradermally or in the preperiosteal plane. In the lower two-thirds of the nasolabial fold, inject into the deep dermis or superficial subcutaneous plane just medial to the nasolabial fold (в–¶ Fig. Hyaluronic acid fillers are reversible if there is a vascular issue or problem because they can be reversed with hyaluronidase. Use only FDA-approved reversible hyaluronic acid fillers in most areas of the face. Key Points for Maximizing Filler Safety in the Nasolabial Region

Nasolabial fold filler