Dangerous Anatomical Zones in Terms of Vascular Structures for Filler Injections to the Temporal Region: A Morphometric CT Angiography Study

BACKGROUND: Filler procedures in the temporal region are frequently preferred in aesthetic practice; however, the complex vascular anatomy of this area poses significant risks. Misplaced injections into the superficial temporal artery (STA) or the zygomatico-orbital artery (ZOA) can cause blindness, while those into the middle temporal vein (MTV) may lead to pulmonary embolism. Therefore, a detailed and integrated understanding of the anatomical structure of the STA, ZOA, and MTV is essential for safe and effective procedures. OBJECTIVES: This study aims to identify the anatomical course of the STA, ZOA, and MTV to enhance injection safety and minimize the risk of complications. METHODS: The variations of the STA, ZOA, and MTV were evaluated on computed tomography angiography images of 200 patients, and vertical distances to six points on the zygomatic arch and horizontal distances to four points on the lateral orbital rim were measured. RESULTS: The most dangerous filler injection areas were identified as follows: in females STA-A2 4.2 cm, STA-A4 4.2 cm, STA-O2 4.6 cm, ZOA-A3 1.3 cm, ZOA-O1 0.8 cm, ZOA-O1 1.3 cm, MTV-A3 2.0-2.4 cm, MTV-O3 0.8 cm, and MTV-O3 4.2 cm; in males, STA-A2 4.2 cm, STA-A3 4.8 cm, STA-O2 4.8 cm, STA-O3 4.9 cm, ZOA-A2 1.5 cm, ZOA-A3 1.7 cm, ZOA-O1 1.0 cm, ZOA-O1 2.0 cm, MTV-A3 2.8 cm, MTV-A5 2.1 cm, MTV-O1 2.0 cm, and MTV-O3 4.1 cm. CONCLUSIONS: An anatomical map of the STA, ZOA, and MTV was created to define key distances for safe filler injections. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .