Soft-tissue fillers have become important for facial rejuvenation as deep fat compartments and facial bones lose volume during the natural aging process. To provide natural-looking results, the physician must have thorough knowledge of the anatomical changes that take place during the aging process and be able to place fillers in specific target areas. As the new field of aesthetic medicine develops, practitioners are using techniques that establish safety profiles to reduce complications and increase patient satisfaction. Technological development has led to the introduction and adoption of cannula to deliver soft-tissue fillers. This has led to a debate on their use over the traditional sharp needles.

Why would physicians use a cannula to inject derma filler as opposed to the traditional needle?

“ Before cannula were developed, needles were the only way to treat. However, nowadays, large bore  cannula offer a much greater degree of safety and precision. “ Dr. Maria Khattar

Are Cannula Injections Safer?

The use of blunt-tipped cannula for the injection of soft tissue fillers is gaining popularity by aesthetic physicians. There are several advantages for the patient and the practitioner of using a blunt-tipped cannula which makes them a preferred option.

Cannula are blunt-tipped which means the injector is able to feel the resistance from structures that the cannula pass through, allowing them to judge how to apply pressure and manipulate the direction of the cannula. This reduces the likelihood of penetrating blood vessels. Injection of filler into the arteries is a serious complication that causes blockage of blood flow to the skin tissue. Treatment with non-traumatic cannula eliminates risk of swelling, bruising or piercing a vessel and lowers pain scores.

Cannula are long and flexible which allows fewer injection points through the skin and wide access within the skin. The ‘fanning’ technique means that from one entry point the cannula can turn in different directions to inject the product into several areas without hurting the patient with another needle puncture. This means less discomfort, pain and far less risk of bleeding, swelling and bruising.

“It is a well recognised fact that injecting with a cannula is much safer than with a needle, especially in a high risk area such as the Nasolabial fold. It is important to emphasise the fact that bruising is almost negligible with a cannula.” Dr. Maria Khattar

Are Needle Injections More Accurate?

Needles vary in length and width depending on their purpose in the medical field. Traditionally fillers have always been injected using typically short, thin and sharp tip hypodermic needles.

The sharp tip of the needle penetrates through different dermal layers into the depth at which filler needs to be injected. Tip of sharp needle is extremely fine making it easier to use. Only small amount of pushing force is needed to channel the needle through the dermis, therefore minimizing damage. Filler is injected into multiple areas in order to ensure even distribution.

Inserting a small needle allows for more control and accuracy especially in areas that require a great deal of precision. An example of this is treating the fine “smoker’s lines” around the lips, where a light hand is required to deliver tiny amounts of product superficially. A small needle often allows for more control and accuracy.

Cannula Vs Needle: An Observational Study

An observational study used cadaver heads to determine the difference in precision of superperiosteal placement between sharp needle compared to the non-traumatic cannula. Dye material and soft tissue fillers were injected at multiple facial sites and the cadavers were dissected to observe for placement.

The results show that the cannula technique had product confined in the deep anatomic layers. Meanwhile, in the sharp needle technique the material migrated in retrograde directions ending up in multiple anatomic layers with higher complication risk of intra-arterial injection. The conclusion was that using a cannula allows for more precise injection.

Click Here for the detailed study.

Ultimately, there are benefits to both methods, depending on the area being treated. It can also come down to personal preference. Some practitioners may feel extremely confident carrying out the majority of their dermal filler procedures using just a needle, or just a cannula, while others may be happy to switch between the two depending on the individual case. Most practitioners will agree that the cannula is a useful tool, even if it is not something they use very often.

“I do understand that many cannot be bothered mastering the use of cannula when the option to inject with a needle is still viable. However, in my opinion, this is like playing Russian roulette as ultimate safety is not guaranteed” Dr. Maria Khattar