July 1, 2021

How to choose the best injection depth for fillers to get the best results and avoid complications

skin layers anatomy needle depth

As aesthetic clinicians, especially if you are relatively new to aesthetic practice, the question of injection depth is likely to be front and centre in your mind.

You may find yourself asking – Do I go deep? Should I be superficial? Or somewhere in between? Chances are, you worry about this regularly and want to know about the Holy Grail of the best depths for each different type of treatment indication.

In this blog, Dr Tim reveals the four factors that affect how you decide on the depth of your injections when delivering dermal fillers, how to tell that you have you needle (or cannula) at the correction depth, plus the advantages and disadvantages of injecting within each layer of the skin.

Dr Tim will be discussing more medical aesthetic training tips as part of his upcoming webinar series, so if you’re looking to increase your CPD-certified learning and want to learn more skills to make you a better practitioner, then step one is to register for the free webinars by Dr Tim.

4 factors that dictate the depth of dermal filler injections

  1. What are the aesthetic indications?
    Put simply, this means – what are you trying to achieve? Of course, this can vary from removing a wrinkle or shadow, to creating definition, or contouring to create curves and strong lines. Each of these plays a role in deciding upon your injection depth, because a crease or wrinkle is a superficial correction, whereas facial contouring is achieved with much deeper injections.
  2. What is the complication risk?
    Having a good knowledge of facial anatomy following an appropriate training course means that you will be aware that there are certain areas of the face where the structures beneath present you with many of the so-called dangers zones which you should avoid with direct injection at certain depths. This would include areas where there is a known presence of significant facial nerves and arteries.
  1. How does it move?
    The differing levels of dermal layers and how the face moves changes how a dermal filler product interacts over time.
    For example, if you are undertaking a treatment to redefine the angle of the jaw and are therefore seeking to emulate bone, but you inject into the superficial fat pads, you will find that upon movement the filler product does not move alongside the jawbone, creating an unnatural result, despite looking very nicely defined when the patient is static. It is vital to take movement into consideration when deciding at which depth to deposit your dermal filler.
  1. How efficiently will the job be done?
    As well as movement, the different depths of injection can influence the efficient use of your dermal filler product, such that clever placing can give you more ‘bang for your buck’. This may mean that, in some cases, a more superficial placement produces a better overall result, whereas placement in the intermediate level may cause product to be lost when in fact a deeper placement improves overall volumisation and provides the support and contouring you are seeking to achieve.

Injecting into the different layers of the skin

Injecting into the Dermis

This layer of the skin is one of the most commonly injected by aesthetic practitioners to reduce lines and wrinkles. By injecting into the dermis, we can rebuild support and strengthen the skin to prevent the breakdown and thinning of the reticular dermal layer which is directly beneath. In the case of very deep wrinkles, you can already see the impact beginning to show in the reticular dermis which may shine through as a pink area.

The main indication for injecting into the superficial to mid dermis is to stop the skin folding process which creates wrinkles. It is also the layer of the skin where you get the most superficial traction or support, so injecting within the dermis can help to correct skin weaknesses and the effects of gravity, such as treating naso-labial folds, marionette lines, the vermillion border of the lips and tear troughs.

How do I know if I am in the right place?

It is simple to establish if you are correctly injecting at this superficial level by checking if, as you elevate your needle parallel with the surface of the skin, the skin blanches indicating that the needle is underneath the papillary dermis, but superficial enough to be above the hypodermis. If you can see a greyness, then you are likely seeing the needle and are too superficial.

  • Advantages:
    It is a generally safe place to inject as the dermis is not close to significant blood vessels.
  • Disadvantages:
    If you are using the wrong product for the indication at this depth, such as a high G prime or thick product and you inject it superficially, you will be able to see lumps where the filler has been placed.

Injecting into the Hypodermis

This is an easier plane for passing through cannulas – which are more resistant at deeper levels and cannot be used in the dermis – but which still provide a superficial depth for addressing shadows, moderate facial contouring, and minor structural improvement in areas where deeper injections would be too risky, such as along the jawline.

  • Advantages:
    By using a cannula at this depth, you will be above the main arteries.
  • Disadvantages:
    The facial artery can be found on the deep side of the hypodermis, particularly when injecting naso-labial folds, presenting a risk of causing a vascular occlusion.

The SMAS and injecting into the deep fat pads

The Superficial Musculo Aponeurotic System (SMAS) provides an important layer for supporting structures. However, we would never try to inject directly into the SMAS. It is often used as a landmark within the dermal layers so that you can determine if you are above it (in the hypodermis), or below it (in the deep fat fads) when injecting dermal filler. This positioning is important if you want to create lift by supporting the ligaments, such as when treating the cheeks to add volume, where you should be injecting underneath the SMAS. For more on the relationship between the ligaments and the fat pads when it comes to facial ageing, watch the Ligament Lesson episode of the Aesthetic Mastery Show.

  • Advantages: Injecting into the deep fat pads is more forgiving, aesthetically speaking, because the area is covered by the SMAS, meaning that there is no risk of visible filler product. By injecting at this deeper level to contour cheeks, chin, and the jawline, the needle placement is on the periosteum, and you are away from the arteries – assuming you are not near the foramen where the arteries enter the face. There is therefore a decreased risk of a vascular occlusion.

Injecting onto the Periosteum

The periosteum can be both a reassuring and worrying place to inject depending on the area of the face. A good understanding of the anatomy is paramount. However, injecting at the level of the periosteum for treating chins and jawlines will avoid the previously mentioned issue of a discrepancy between product and bone on movement of the jaw.

How do I know if I am in the right place?

You will know exactly where you are when you are at the level of the periosteum or bone because you feel the needle touching something.

  • Advantages: By placing filler product deeply in these indications, there is less risk from unnatural movement of the product, the product may last longer in this layer, and have a reduced incidence of migration – all of which provides long term stability.
  • Disadvantages: There are some real dangers areas when it comes to deep injections, so we recommend that you watch the Don’t inject DEEP here episode of the Aesthetic Mastery Show where Dr Tim discussed the 6 most dangerous facial areas where you must not inject deeply due to the risk of occluding blood vessels and causing a serious complication.

The key to knowing the depth of your injection comes from depth checking by understanding the different thicknesses of the skin on the face – the thinness of the tear trough in comparison to the thicker glabella, for example – alongside the visual and tactile feedback you receive during manipulation of your needle or cannula.

Download our guide to the 13 extra risky injection areas which includes a facial vessel map.

Are you anxious about delivering cosmetic injectables safely?

If you want to learn more about mastering medical aesthetic treatments and complications, or conquering the anxiety of where to place your needle, then register for the next Dr Tim webinar.

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Dr Tim Pearce eLearning

Dr Tim Pearce MBChB BSc (Hons) MRCGP founded his eLearning concept in 2017 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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