Cannula for Dermal Filler Injection

Patient Education Topic: What is a cannula and why does it matter to dermal filler injection?

Well, all of that hyaluronic acid goodness needs to get under the skin somehow, right? When you think of injections, your mind automatically goes to needles. Indeed needles are a good tool for injecting dermal fillers like Restylane and Versa. Needles are preferred for injection of filler in some locations of the face (frequently lip filler), and are often favored for precision. The downside to using a needle to inject dermal filler is that needles are readily capable of piercing an artery or a vein. The concern here is that filller could be deposited accidentally into that artery or vein, causing (very!) rare problems like vascular occlusion (clogging of the artery) or in some (extremely!) rare cases, vision loss.

One useful practice to reduce the likelihood of accidental vascular injection is aspiration, or pulling back on the plunger of the syringe, and observing for backflow of blood. This is a common practice, and something that I do with every needle pass. Another way to decrease the likelihood of piercing an artery or a vein is to use this handy blunt-tipped injection device for filler: the cannula.

Cannulas kind of look like needles, but they aren’t sharp on the end, and the port where the filler comes out is actually on the side near the tip. A needle is used to create a port in the skin where the cannula initially enters, and then the cannula traverses under the skin to deposit dermal filler. Cannulas are great for cheek filler, marionette lines, temple filler, jawline filler, and sometimes the nasolabial folds. The idea is that if the cannula bumps into a blood vessel, it’s less likely to pierce it, making this injection technique safer from a vascular occlusion standpoint, and probably bruising as well.

The face is a literal minefield of blood vessels, and vascular concerns will always be top of mind for injectors when it comes to patient safety. Aspiration when a needle is used, and cannula use are two ways to increase the safety of dermal filler injections. Additionally, safe injectors will be packing a refrigerator full of reversal agent for hyaluronic acid dermal fillers, and as a patient, it’s okay to inquire about safety. You’ll want to know that your injector is a good ‘girl scout’ and has a plan to prevent and treat complications.