April 13, 2023

Positive Aspiration Fillers

Aspiration, although controversial is a great safety enhancement when performing dermal filler injections; and, if done correctly can reduce the chance of experiencing a vascular occlusion by 30-80%.

In this blog, Dr Tim Pearce discusses some additional safety tips, combining movement of your needle with aspiration to increase your ability to detect large vessels prior to injecting, further decreasing your risk of severe vascular occlusion and increasing safety for you and your patient.

Do you feel anxious about causing complications? Many clinicians feel so overwhelmed with the thought of causing a vascular occlusion that it stops them growing their aesthetics business. Dr Tim is currently hosting a webinar series to help you overcome your fear of complications so that you can uplevel your knowledge, and increase your CPD-certified learning to build a successful aesthetics business. Sign up here >>

Aspirating when injecting dermal fillers, always hotly debated

Dr Tim has noticed an increasing trend towards advocating moving the needle during injection, instead of aspirating, despite aspirating having what he believes to be the most measurable impact on safety of any safety step carried out during the delivery of dermal filler injections. He wants to show aesthetic clinicians a new step which can be done to increase safety and has demonstrated that it does detect intravascular passage of the needle.

Many opponents of aspirating do not analyse the benefits of aspirating as a screening test, explains Dr Tim. They constantly focus on the false negatives and the false positives to dismiss the entire idea, ignoring the proven incidence of true positives and what that means for patients. Put simply, a positive aspirate is the only cheap and accessible way that you can detect the most dangerous situation in medical aesthetics – the placement of an injecting needle in the lumen of a vessel. The lumen is the empty space inside a blood vessel where the blood flows. Such critics incorrectly claim that any movement, no matter how small, will invalidate this information; this would only be true if blood vessels were infinitely small.

A syringe filling with blood clearly has a strong correlation with the presence of blood vessels and this information allows you to change your course of action prior to the point of no return, but what if movement itself could provide you with more information than a static aspiration and injection?

Aspirating and negative pressure

For aspirating to work, you are relying on a pressure gradient. You create a negative pressure within the syringe, which is greater than the pressure in a blood vessel (where blood is liquid).

The problem with negative pressure is that it can also suck against tissue or suck vessels closed if you pull back too hard, therefore negative pressure is not always a guarantee that you will achieve a transfer of blood, but it is required for the physics to work.

The negative pressure is held within the syringe whilst you move the needle, but if you move into the passage of a blood vessel, you will get a flashback, more often than not, as the pressure equalises, telling you that you are near a vessel and should not continue injecting.

dermal filler aspiration gel testIn the illustration and video, you can see Dr Tim priming a filler needle, placing it into a layer of gel and aspirating to create a negative pressure. During his years of experience, he noticed that occasionally positive aspirations occur after small movements of the needle, which makes sense.

When you aspirate, you create a negative pressure at the tip of the needle when you are in the tissue. There is no way to alleviate that negative pressure until you pass into a blood vessel where the pressure is alleviated by blood moving up into the syringe. This provides the information we need as a mechanism for detection of the presence of blood vessels in the path of the needle. It has been proven, in many experiments, that primed needles allow for the detection of the needle inside a lumen.

Dr Tim explains that this does not need to be perfect to be extremely valuable, given that detecting intraluminal passage through a large vessel would highlight the one situation most feared by aesthetic clinicians. A 30 to 80% reduction in risk is freely available to those who decide to take the time to understand the mathematics of screening and probabilities with this practice.

Aspirating is not a black and white answer to the question,

“Am I in a vessel?”

But…it is the answer to the question,

“What is the probability that I am near a large vessel?”

New aspiration safety tip: how to combine movement and aspiration

aspirating needle botox fillersImagine inserting a needle and pushing down through and past a blood vessel, which you cannot see below the skin’s surface, then aspirating, but as you do, you retract the needle upwards along its path (which is also the linear path of product placement). If you cross a vessel as you retract, and thanks to negative pressure, you will see a positive aspirate. This will indicate the presence of the vessel before you start injecting freely in the area and potentially block a vessel as you do the retrograde injection.

The core concept with moving the needle in this way is that of spreading the risk, not reducing the risk, but this might reduce the seriousness or severity of a vascular occlusion, rather than reducing the frequency of occurrence.

The underlying principle behind moving the needle is that you can have the best of both worlds – detecting intravascular passage of the needle, in some instances, and the benefit of not placing too much product in one place.

Dr Tim concludes that it would be reasonable to check the path of the needle using aspiration and movement, which allows you to go back in and inject along that path more safely, providing you did not get a flashback.

For more on the topic of aspirating, have a read of Dr Tim’s blogs

You can also take a look at the full results of Dr Tim’s aspirating experiment: how quickly does your filler brand aspirate…if at all? – this was performed on him (using his own arm!) with multiple dermal filler brands showing some interesting outcomes.

Aspirating is always a hot topic and Dr Tim loves to hear from his followers, so why not drop him a comment on social media if you have further questions or your own stories and experience to share; you can find Dr Tim Pearce on Instagram.

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Aesthetics Mastery Show

Increase Your Injection Safety With This Aspiration Trick

In this episode, Dr Tim explains how properly performing aspiration can reduce your chances of experiencing a vascular occlusion by 30-80%. He demonstrates an additional method combining movement of your needle and aspiration that will help you detect large vessels, further decreasing your risk and increasing your overall safety. Watch the full Aesthetics Mastery Show here.

Brandi Smith commented:

“So I love the principal of this but my question would be if you have a clear pre-check and you go back in, there is no guarantee that you are in the exact track you went down previously, right? The slightest shift in angle can send you down a different path where a vessel may now be… but you have a false sense of security now. The same can be said for aspirating prior to a supraperiosteal aliquot where you park, aspirate and push – a slight movement can change things… but I think it just reinforces that there is no guarantee of safety when injecting. Just to be clear I am a fan of aspiration. I understand that it does not mitigate all risk and I need to always be aware of the anatomy, BUT I would rather have that check because anatomy varies. I have had quick positive aspirations in an anticipated “safe zone” and for me I would rather error on the side of caution. I will always aspirate. I am interested to see more on this technique.”

Dr Tim replied in person, saying:

“None of this should give you a false sense of security, because we know aspirating is probabilistic, not absolute (like EVERYTHING we do for safety). I don’t think it is the slightest shift-I am quite routinely keeping my needle within a mm of where I want it to be (eg Vermillion border, tear trough, nonsurgical rhinolasty) and most of the vessels we are worried about have lumens bigger than a mm. What you will have at the end of a pass is a lower probability of being in a vessel and not knowing. Assuming the test is 30% sensitive, you will reduce an already extremely rare event by 30%, which is actually a HUGE benefit- there is nothing else we know that does things that measurably.”

Dr Tim Pearce eLearning

Dr Tim Pearce MBChB BSc (Hons) MRCGP founded his eLearning concept in 2016 in order to provide readily accessible BOTOX® and dermal filler online courses for fellow Medical Aesthetics practitioners. His objective was to raise standards within the industry – a principle which remains just as relevant today.

Our exclusive video-led courses are designed to build confidence, knowledge and technique at every stage, working from foundation level to advanced treatments and management of complications.

Thousands of delegates have benefited from the courses and we’re highly rated on Trustpilot. For more information or to discuss which course is right for you, please get in touch with our friendly team.

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