Cannulas are commonly used in medical aesthetics to add volume, contour and correct various regions of the face, neck, hands, décolletage and other body areas. There are several advantages to using blunt-tipped cannulas for facial augmentation in areas such as the tear trough, forehead, temples and all other areas of the face . DPI Cosmetology has partnered with Dr. Irina Geliev to put all the knowledge we have in one blog post. By the end of this article you will know the difference between sharp dermal needles and blunt dermal cannulas; product placement and treatment outcomes with these increasingly popular injection tools, and benefits of using them.


Traditionally, dermal fillers have been administered to the face via a hypodermic needle, however, aesthetic cannulas have become more popular over recent years, particularly for larger areas of the face. Indeed, many dermal filler products are now actually packaged with both a needle and a cannula in order to allow the practitioner more choice when deciding how to inject the product. But as a practitioner, how do we decide between the two methods when treating a patient?

sharp needle vs blunt cannula

What are the main differences and possible complication?

Probably the most obvious difference between a needle and a cannula is that the tip of a needle is sharp while a cannula is blunt (meaning it is opposite from sharp). One of the main issues when using a needle to administer dermal filler is the likelihood of swelling and bruising post-treatment. Once the needle is inserted, there is a chance that it will pierce the blood vessels underneath the skin, resulting in a bruise. While practitioners can take various measures and use their knowledge of facial anatomy to minimise the risk of bruising, even the most experienced of practitioners cannot guarantee that a patient definitely will not bruise.

Needles vs Cannulas: What are dermal blunt cannulas? Differences between sharp dermal needles and blunt cannulas.

Figure 1

In contrast, a cannula does not pose the same risks due to its blunt tip. While a small bore needle is used to make the initial entry point, once the cannula is inserted into the skin, it is far less likely to pierce and pass through the blood vessels. Instead, it simply pushes past the vessels, causing less trauma underneath the skin and therefore, less chance of bruising post treatment.

Another risk relating to the sharp tip of the needle is not just piercing the blood vessel but actually injecting the filler into it, leading to a vascular occlusion which, in turn can result in far more serious complications. Again, there are certain measures that practitioners take to ensure that this does not happen, however, it is something that must be considered when using a needle. See Figure 1 for a complication in the nose area after injecting a dermal filler with a needle, which my fellow colleague has encountered in her practice.

The risk of a vascular occlusion is one of the reasons why many practitioners prefer to use a cannula in “high-risk” areas such as around the eye, as, unlike a needle, a cannula will not pierce any blood vessels in the area and is therefore less likely to cause any severe complications.

The choice of size of blunt cannulas:

First of all,

Don’t use 27G cannulas for the high risk areas, as the 27G cannulas are nearly as sharp as needle.
However, you can use these cannulas for non high risk areas. SoftFill cannulas are a good choice for that.
  • Tear troughs use 25G cannula
  • Cheeks/mid-face 25G or 22G cannula (the choice depends on stability and cohesivity of a filler) 
  • Nose correction 22G cannula 
  • Jaw line 22G cannula 
  • Nasolabial folds, marionette lines, infralabial and mental areas the best is to use 25G cannula

At DPI Cosmetology online shop you can find a selection of JBP Nano Cannulas for these areas.

With the cannula method, a small introducer needle is used to create an entry point for the cannula. The cannula is then inserted into the puncture site and maneuvered along the natural planes of skin tissue; this provides a large area to place the dermal filler through a single entry point.

This large area made available by the cannula means that the injector is now able to accurately place the filler in multiple areas of the face via the one entry point in the skin (rather than the multiple injections that needles require to achieve similar results). And because the filler can be distributed smoothly and uninterrupted along the tissue plane, a more flawless, natural look is achieved.

What kinds of benefits do patients see using the cannula method?

Needles vs Cannulas: What are dermal blunt cannulas? Differences between sharp dermal needles and blunt cannulas.

Figure 2

Both physicians and patients are seeing the benefits of this approach.

For physicians, using a blunt-tip cannula allows for a more accurate placement of filler, as they are able to feel resistance as the cannula travels underneath the skin and can manipulate where the filler is deposited. Because the cannula allows the injector to more seamlessly place a smooth layer of product rather than multiple dollops, less massaging and manipulation of product is needed to achieve a beautifully smooth and natural looking result. Additionally, because the blunt tipped cannula is much less likely to pierce a vessel, the rare risk of intravascular compromise is further reduced.

For patients, the cannula approach is less painful than traditional needles as there are far fewer entry points. There is also a decreased risk of bleeding, bruising and swelling. While needles are more likely to cause bruising and swelling because their sharp tip can penetrate a vein or artery (causing bleeding), cannulas are less likely to do so, because their blunt tips typically push these obstacles aside.

Needles vs Cannulas: What are dermal blunt cannulas? Differences between sharp dermal needles and blunt cannulas.

Figure 3

Finally, decreased swelling and bruising results in minimal downtime and patients typically return to their normal routine immediately following their treatment.

See Figure 2 and Figure 3 for my personal results with the cannula method. And remember: if you want to learn more about this topic or any other aesthetic treatment, you can contact DPI Cosmetology team and arrange a private master-class for your clinic or for yourself.

 

So does it mean we should say “no” to the dermal needles?

Not at all!

While the cannula method for injecting dermal fillers offers many benefits, there are cases when using the traditional needle may be more appropriate since the needle method is more precise and creates more defined shapes and contours. For example, Mesorelle needles come in different sizes and in a packaging of 100 pieces.

As with any treatment, we take a personalized approach to ensure the patient achieves his or her desired results in the safest and most effective way possible.

Contributed by Dr. Irina Geliev