Evaluation of Facial Artery Course Variations, Diameters, and Depth Using Doppler Ultrasonography: A Systematic Review and Meta‐Analysis

The facial artery (FA), as the primary vascular structure of the face, exhibits numerous anatomical variations. Determining its anatomical variation (vascular mapping) by ultrasonography (US)-a non-invasive, low-cost, practical, and bedside-applicable imaging technique-helps achieve safe aesthetic injections, averting complications such as ischemia and necrosis. This study aimed to evaluate the anatomical characteristics of FA under the guidance of US, including course variations in relation to the nasolabial fold (NLF), depth, and diameter. This systematic review and meta-analysis used the 2020 update of the PRISMA guidelines. The detailed protocol is registered with PROSPERO. Original studies with extractable numerical data that applied Doppler US in normal adult populations to illustrate FA anatomy were evaluated. The primary two outcomes of the study were (1) the pooled visualization rate of the FA in each of the three anatomical levels and (2) the pooled prevalence of each FA course variation according to the NLF. A systematic search through the three online databases identified 1087 records, of which 580 underwent title and abstract screening after duplicate removal, and 10 studies were included. The visualization rates at three anatomical facial levels were 100%, 99.9%, and 99.8% of all arteries. FA running medial to the NLF (type A) (46.2%), followed by FA crossing medial to lateral of the NLF (type C) (22.5%), were the most frequent courses of FA in relation to the NLF. In contrast, the FA running lateral to the NLF (type B) (12.0%) was the scarcest variation. The FA became more profound in the skin layers as it ascended in the face from level 1 (6.27 mm) to level 3 (8.04 mm). Moreover, the FA narrowed in diameter from level 1 (2.14 mm) to level 3 (1.46 mm) as it branched out and approached its termination point. Therefore, the total prevalence of angular, lateral nasal, and superior labial artery as the final branch of the FA in our study was 71.8%, 27.9%, and 5.7%, respectively. According to the results, the US could detect FA in almost all cases at the three levels of the face, including the lower border of the mandible, cheilion, and lateral nasal ala. This systematic review and meta-analysis provided a comprehensive anatomical knowledge of the Doppler-visualized FAs as an exemplary schema of pre-procedural vascular mapping that can help aestheticians prevent intravascular injections, exerting safer performance during cosmetic procedures. PROSPERO number: CRD42024616195.