The needle versus cannula debate is frequently discussed in aesthetic medicine, particularly in regards to safety. A recent study published by the Department of Dermatology at the Feinberg School of Medicine, Northwestern University, has suggested that cannulas are less likely to cause a vascular occlusion than needles when injecting filler. The study evaluated injection practices, injection volumes and prior intravascular occlusion events of 370 US-based dermatologists, with a total of 1.7 million injections. Results showed that one occlusion occurred per 6,410 injections via needles, compared to one occlusion per 40,882 injections with cannulas.1
With evidence indicating that cannulas are a safer method, aesthetic practitioner Dr James Shilvock and consultant plastic, reconstructive and aesthetic surgeon Mr Dalvi Humzah consider whether the industry should be replacing needles as the main instrument for aesthetic injections.
Dr Shilvock is the clinical lead for the Dubai and Birmingham Consultant Clinic branches, a brand which has adopted the cannula as its default method of injection. He comments, “The reason the brand first started using cannulas was for safety, as they’re much less likely to cause vascular occlusions and other complications. This is because, when used correctly, the cannula should move the vessel out of the way rather than hitting it like a needle, also lessening the incidence of bruising. Now, 90% of the treatments we perform are with a cannula, although we do still use needles for noses as we wouldn’t achieve the necessary accuracy otherwise.”
Dr Shilvock also notes that as patients are becoming more educated on injection techniques, they are having more people present to the Consultant Clinic purely to be treated with a cannula. He says, “As there is more information emerging about aesthetics, patients are more aware of what the safest options are. We find that a lot of our patients choose us specifically because they know we always use cannulas, and often people come to us having just experienced a complication from a needle injection administered by a different practitioner. I think if we continue to put out content that informs people of the dangers of aesthetic procedures, and the ways they can be made safer, then patients will make choices which reflect that. We’ve also found that cannulas give our patients better results, so for us it’s a win-win!”
While Mr Humzah agrees that cannulas have less chance of bruising and causing an occlusion, he emphasises that they still cannot be considered 100% safe. He comments, “It isn’t just about the instrument, but about how the practitioner uses it. I run a training course for cannulas and I’ve had even experienced doctors come in and be completely unaware of how to use them correctly. For example, I’ve seen them forget all about aseptic techniques which can cause infection.”
He continues, “People also need to bear in mind that there is no evidence to say that a cannula will NEVER cause a vascular occlusion – it’s just less likely.”
"It isn’t just about the instrument, but about how the practitioner uses it"
Mr Dalvi Humzah
Why are needles more prevalent?
Dr Shilvock believes that some practitioners may be prioritising cost over safety by choosing to use needles. He comments, “When you buy filler you often get a needle included in the box as part of the price, whereas you have to buy cannulas separately, which aren’t cheap. Because of the expense, I worry that practitioners would rather save money than invest in something which is a lower-risk for their patients. Similarly, in terms of competitive pricing, a cannula treatment will be more expensive and so clinics may prefer to use needles in order to keep the prices down and attract more business. However, I urge my colleagues to remember that just because something is cheaper, it doesn’t mean it’s the best option, and it may end up being worse for your reputation in the long run. It’s something that the practitioner needs to weigh up for themselves.”
Dr Shilvock also advises more training providers to incorporate cannulas into their curriculum, as currently he believes the specialty is focused primarily on needles. He comments, “In order for practitioners to be more confident and comfortable when using a cannula, they need to have received the correct training. Unfortunately, there aren’t as many courses out there that focus on cannulas, and practitioners begin in the industry solely using a needle. Many then continue to use them as their main instrument throughout their career, as it’s what they know and are comfortable with. I would recommend that new practitioners seek out a course on cannulas for themselves, because otherwise we have a large number of inexperienced injectors performing what I believe to be the more dangerous method.”
Mr Humzah agrees, commenting, “Using a cannula is not something people should just be picking up on the job, which at the moment it mostly is. It’s important that the industry provides educational courses for both old and new practitioners to supply them with vital knowledge, for example how to choose the right cannula for the treatment/patient. Without the right training, even the safer methods can cause the patient harm.”
A combination approach
Mr Humzah believes that while cannulas have their benefits, practitioners should not limit themselves to just one instrument. He comments, “In my experience, there are pros and cons to both methods. Cannulas can be beneficial for certain procedures, for example when injecting a large surface area, however I believe that needles are still needed for things like contouring and fine adjustments. To me, you aren’t a good aesthetic practitioner if you can only use a needle, and you aren’t a good aesthetic practitioner if you can only use a cannula. What’s important is having a good knowledge of both techniques and being able to recognise when one is more beneficial to the patient than the other.”