Three-Dimensional Computed Tomography Scanning of Temporal Vessels to Assess the Safety of Filler Injections

Abstract

Background Temple filler injection is one of the most common minimally invasive cosmetic procedures involving the face; however, vascular complications are not uncommon. Objectives This study aimed to investigate the anatomy of the temporal vessels and provide a more accurate protocol for temple filler injection. Methods Computed tomography (CT) scans of 56 cadaveric heads injected with lead oxide were obtained. We then used Mimics software to construct 3-dimensional (3D) images of the temporal vessels described by a coordinate system based on the bilateral tragus and right lateral canthus. Results In the XOY plane, the superficial temporal artery (STA), middle temporal artery (MTA), zygomatico-orbital artery (ZOA), posterior branch of the deep temporal artery (PDTA), and lateral margin of the orbital rim divide the temple into 4 parts (A, B, C, and D). The probabilities of the STA, MTA, ZOA, and PDTA appearing in parts A, B, C, and D were 30.73%, 37.06%, 39.48%, and 77.18%, respectively. In 3D images, these vessels together compose an arterial network that is anastomosed with other vessels, such as the external carotid, facial, and ocular arteries. Conclusions 3D CT images can digitally elucidate the exact positions of temporal vessels in a coordinate system, improving the safety of temple filler injections in a clinical setting.

Vascular anatomy of temporal fossa

“…The mean diameter of the ZOA was found to be smaller than in other samples, 44,45 at 1.2mm (SD: 0.2), and it had extensive anastomoses with various periorbital arteries at the lateral orbital rim (Figure 15). The authors maintained that when injecting filler into the layer between the deep and superficial temporal fascia, caution should be taken to avoid the ZOA.…”

“…36 The zygomatico-orbital artery (ZOA) Despite being the largest artery in the temporal area, with a mean diameter up to 2.52mm, the anatomy of the zygomatico-orbital artery (ZOA) has rarely been studied in relation to filler injections. 44,45 The ZOA forms from the external carotid artery, as the main branch of the MTA; and runs parallel to the upper zygomatic arch. Subsequently, it runs horizontally toward the lateral canthus and transfers to the palpebral and superficial orbital arteries.…”

“…Together, the DTAs and MTA supply blood to the temporalis muscle. 33,44 One study located the anterior branch of the DTA intramuscularly, 50 while a cadaveric study evaluating fifty-six Chinese heads using CT imaging found the posterior branch of the DTA arose from the maxillary artery and ran into the temporal region at the midpoint of the zygomatic arch, at a depth of 14.13mm (SD: 6.26mm). From this point, the branches of the DTA ran directly upwards.…”

“…From this point, the branches of the DTA ran directly upwards. 44 As these two studies investigated only single branches of the DTA, it remains unclear if, like other major arteries, the DTA may consist of anterior, middle, and posterior branches.…”

“…90,159 However, other authors argue that HA fillers are most safely placed deep to the temporalis muscle, directly on periosteum. 33 Based on their cadaveric and CT assessments, Chen et al 44 proposed that the safest planes with the fewest vessels are the periosteum and the loose areal tissue. The authors suggested that sharp needles are best used in the plane periosteum and subcutaneous tissue, whereas blunt cannulas should be used when injecting into the loose areal tissue.…”