Anatomical Depth of Labial Arteries in Dermal Filler Procedures: A Meta-analysis With Clinical Implications

Lip augmentation procedures are increasingly popular in aesthetic medicine, and precise knowledge of labial arterial anatomy is essential for safe outcomes. The superior labial artery (SLA) and inferior labial artery (ILA) serve as critical anatomical landmarks for these procedures, and their positioning guides injection techniques. But despite their importance, there has been uncertainty about the precise depths of these vessels across different facial regions, creating potential risks during procedures. Therefore, we conducted a comprehensive meta-analysis to quantitatively compare arterial depths at three distinct levels of the SLA and evaluate average depths of both the SLA and ILA. Analysis of multiple arterial measurements (277, 218, 252, 414, and 295 arteries) at key locations - between the cheilion and cupid's bow peak, at the cupid's bow peak, and at the facial midline - revealed consistent average depths ranging from 4.59 mm (95% CI: 3.91-5.10) to 4.90 mm (95% CI: 4.57-5.61). These findings demonstrate that the vessels maintain relatively consistent depth beneath the vermilion surface, supporting safe injection guidelines of up to 3.5 mm in most lip regions and up to 4 mm in the superior vermilion. While the SLA and ILA showed similar average depths, practitioners should consider using high-resolution ultrasonography before extensive augmentation procedures for additional safety assurance.