Ultrasonography-guided Cannula Method for Hyaluronic Acid Filler Injection with Evaluation using Laser Speckle Flowgraphy

Hyaluronic acid (HA) is present in the connective tissues of the skin and decreases with age. HA fillers are popular as facial rejuvenation treatments. They are generally considered safe; however, complications, such as cutaneous necrosis and blindness due to vascular embolism, sometimes occur. Because vascular embolisms are likely associated with the deep placement of HA fillers, a strategy that involves injection into superficial regions (the conventional method) is commonly used to reduce risks. However, deep injections to achieve revolumization are becoming common, even in high-risk areas for intravascular infusion. We aimed to study the usefulness of the ultrasonography-guided cannula method for preventing intravascular infusion of HA fillers. An HA filler was injected into the region just under the dermis on the left side of the face of a 38-year-old man using the conventional method, and another HA filler was injected into the periosteum on the right side using the ultrasonography-guided cannula method. The skin blood flow on both sides was compared using laser speckle flowgraphy (LSFG). The ultrasonography-guided method was successful in detecting the cannula and the blood vessel, and the HA filler was safely injected into a deep region. Using LSFG, a difference in skin blood flow between the 2 methods was detected. The ultrasonography-guided cannula method was effective in aiding the safe injection of an HA filler in a deep high-risk area and maintained skin blood flow. LSFG may be adopted to evaluate skin blood flow after HA filler injections.