Hyaluronic acid-related sudden onset, painless loss of vision and other frightening side effects of Dermal Filler that every practitioner should understand.
I have attended several conferences in facial aesthetics since I left the world of fulltime NHS employment in August 2013. This has been an interesting 6 months in the world of cosmetic injectables and I have noticed a recurring unofficial theme; something that everyone wanted to talk about despite the best-laid plans of the conference organisers. Merz handled this well in their conference in the Convention Centre Dublin on 13th March by designating a full day to the topic.
Everyone wanted to talk about the majorly rare and majorly profound complications of dermal filler- induced skin necrosis and blindness. The collective knowledge base is incomplete but there is a need for some information for practitioners to be available online – this will buy essays papers evolve and this blog-post will be open to challenges; I’m happy to accept them. But why is everyone suddenly talking about these issues? Until the end of 2013 most of us in the West have probably not taken enough notice of the South Korean case series published in July 2012 in the American Journal of Ophthamology, which cited 1 patient who, after being treated with hyaluronic acid in the nasolabial and glabellar regions, suffered ophthalmic artery occlusion1. But when US and UK practitioners started to report the same complication, an almost identical news story broke in both the US2 and the UK3. In both stories, 3 patients, aged in their 30s, 40s and 60s suffered some or total blindness after treatment with hyaluronic acid.
At the Merz Aesthetics conference this hot topic as well as the similarly frightening, filler-necrosis, were addressed firstly by the GP-turned medico-legal advisor, Dr Stephen Bassett then research paper writing plastic surgeon Mr Chris Inglefield and the massively experienced Harley Street Nurse Practitioner, Ms Marie Duckett. We were first reassured of the rarity of these conditions (blindness sitting at around 1 in 5 million treatments and skin necrosis at around one in 1 million treatments) and then presented with the excellent “Expert Consensus on Complications of Botulinum Toxin and Dermal Filler Treatment’4 and finally, some anecdotal but useful expert theories as to why exactly the injection of Dermal Filler into the face can lead to blindness.
Dermal filler-induced blindness
Dermal filler-induced blindness is not caused by injecting dermal filler into the eye. The sclera is tough; one cannot accidentally put a needle through the eye and inject dermal filler in, and if they did, it is unlikely to cause irreversible and sudden onset blindness. No, blindness caused by Dermal filler is best compared to Central Retinal Artery Occlusion (CRAO).
This condition is when a thromboembolism lodges in the retinal artery leading to ischaemia of the retina and a sudden painless loss of vision5. Filler blindness is thought to be a similar entity only instead of a thromboembolism leading to ischaemia of the retina, it is thought to be caused by dermal filler (hyaluronic acid) itself.
How can I avoid filler blindness?
There are several factors that I have gradually learned over the past 6 months. On my foundation training course for Botulinum Toxin and Dermal filler I illustrate this point by describing the difficulties faced by Foundation Year 1 Doctors in learning to puncture the radial artery during an “ABG’ (arterial blood gas) as part of many routine medical admissions. Arteries and arterioles are hard. They are hard because they contain pressurised blood. Veins are soft, so most bleeding and bruising we see in aesthetics is due to venous bleeding. The radial artery usually bounces off and slides away from the needle during attempted arterial-puncture, that is unless it is first pinned down to the lateral distal radius with a thumb or finger. On my course I demonstrate the difficulty in accidentally puncturing an artery with a needle by swinging a needle and syringe down onto a pencil resting on the table. The pencil slides to one side when I do this. If I hold it down, I can poke the pencil with the needle.
A radial artery measures approximately 2.3 mm in diameter6 whereas a facial artery measures around 1.6 mm in diameter in the mandibular region7 and much smaller than this as these arteries branch into arterioles, so we are talking about an extremely small, moving target. The next problem is anatomy. To use anatomical broad strokes, the carotid artery branches off in the neck to become the internal carotid (supplying everything inside the skull- i.e. the brain) and the external carotid (supplying everything outside the skull- i.e. the face).
When dermal filler blocks off a branch of the external carotid artery, and that branch supplies something which has no collateral supply (an endartery), the area of tissue deprived of a blood supply will become ischaemic and soon afterwards, necrotic. That’s what we think causes filler-related skin necrosis (see below).
How we manage to cause blindness is a completely different aetiology altogether. For filler blindness to occur, as we have said, blood supply to the retina must be disrupted. But how does filler do this if the only injections we are delivering are in areas supplied by the external carotid and the retinal artery is supplied by the internal carotid system? We know a little about this due to studies done in stroke patients. The contrast MRI film below shows a stroke patient with occlusion of the left internal carotid artery. It also demonstrates that the external carotid artery is supplying some collateral blood flow via an anastomosis8. The external/internal carotid blood supply is full of anastomoses. These appear to vary from person to person and seem to represent the mechanism for dermal filler injected into an “external carotid’ branch ending up in an “internal carotid’ branch, i.e. the retinal artery. If this is the mechanism, then it follows that there is also a risk of causing a “filler stroke’. To my knowledge there are no reported cases of this yet, so we will not discuss this theoretical risk further here.
The next factor to understand is the pressure involved. For me, I feel like this issue is the “saving grace”. We can’t do anything to stop us blindly cannulating an artery or arteriole and there is no realistic way of identifying external-internal carotid anastomoses, but we can control the pressure we exert with our thumb as we inject dermal filler. As already mentioned, arteries and arterioles contain pressurised blood. Let’s assume that you have cannulated an arteriole and you inject filler during the patient’s diastole. You can expect that upstream from where you have cannulated, there is a pressure of between 70-100 mm Hg in most people.
So, if you were to squeeze dermal filler from the tip of your needle and it exerts less than 70 mm Hg, it is physically impossible (thanks physics!) to force dermal filler up that arteriole and into the internal carotid system.
That’s the theory anyway. Two implications of this theory that I have thought of today:
- For once, hypertension could be considered a protective factor against something – i.e. filler blindness (unfortunately it’s still a risk factor for other forms of retinal blindness).
- Drug companies could modify their dermal filler syringes in order to reduce this risk. Also, a larger-bore needle could help reduce the risk.
Emergency management of filler blindness
It will be a bad day for both of you. There is no evidence to show this working; as filler blindness is extremely rare, it is unlikely that we will ever have a clinical trial to demonstrate an effective management plan. Any such emergency management plan will likely be formed based on expert opinion and common sense. As there are similarities between CRAO and “filler blindness’, the same treatment principles might be useful to consider. It should be noted however, that although “medical school text book’ management principles, there is little evidence for these in the management of CRAO either9. I have adapted these from the website Medline Plus, below.
- Inhaling a carbon dioxide-oxygen mixture. This treatment causes the arteries of the retina to dilate.
- Massage of the eye (sometimes known as “eye-CPR’).
- An emboli-busting drug (in the case of hyaluronic acid, this would be hyaluronidase- possibly delivered intra-arterially by an adventurous interventional radiologist).
To be clear, your filler-blind patient needs to see (no pun intended) an ophthalmologist, preferably in a hospital with interventional radiology, immediately. Although you will be shaken, it could be beneficial for you to attend and explain the theory presented here as to how this might have happened. Don’t tell them about the pun above; they will have heard that one before.
Filler skin necrosis
Still frightening enough to make you think twice about your career choice, less rare than filler blindness and just as hot a topic at aesthetics conferences, is filler skin necrosis. Information on how to treat this condition has been extremely slow to emerge but, thanks to the “Expert Consensus on complications of Botulinum Toxin and Dermal Filler treatment“ (March 2014) we at last have some guidelines on how to manage this nightmare scenario. This post is made partly from that publication but also taken from my knowledge and experience from the past year of attending aesthetics conferences funded by Galderma and Merz.
This is the easy part. Most people, if they know enough about skin necrosis to fear it, will know the basics. You inject dermal filler, the surrounding skin goes white, you take off your gloves, gulp, call an ambulance and hand in your notice. Thankfully it’s not quite as bad as this. We’ll talk about prevention next, but first, let’s consider the risky areas. From the 32 cases reported worldwide (as of March 2014), most were from injections in the nasolabial region with glabellar frown lines being the second most common area. Blanching surrounding the area injected is the most common initial presentation if arterial occlusion has occurred but an abnormally dark-coloured bruise could be a sign of a venous occlusion- not as catastrophic but still much more spectacular than normal bruising. Following the initial arterial occlusion you might expect your patient to experience pain (immediately); but not always. This blanching would then be expected to give way to mottling and finally grey and black as the skin becomes necrotic.
Is it possible to avoid this? In short; we don’t know. Obviously if you avoid injecting filler into arteries you’ll consequently avoid causing this complication, but whether or not that is possible is still up for debate. Some (including myself) might argue that if you are injecting filler anywhere you should withdraw the plunger and look for flashback every time you are about to inject. The counterargument to this is that the product won’t allow for blood to be pulled up a syringe due to its high viscosity. To decide this for myself I did the following experiment.
Emergency management of filler skin necrosis
This section is a lot more hopeful now compared to how it would have been 6 months ago, thanks to the Expert Consensus on Complications of Botulinum Toxin and Dermal Filler Treatment4. For the first time, we have a guideline for the emergency management of dermal filler skin necrosis. This is both good and bad for practitioners. It could be viewed as bad as a practitioner not aware of the guidelines who is unfortunate enough to have a patient develop filler skin necrosis could be heavily criticised during legal proceedings for having not been up to date in their field. On the other hand, for those of us who know about this management plan, it provides some hope that we can reduce or even reverse the effects of filler skin necrosis or at least demonstrate during legal proceedings that we have done everything reasonably expected of us. There is a beautiful protocol in the aforementioned document “Expert Consensus on Complications’“ which I have adapted below.
As you can see, once you recognise that skin ischaemia is present, you should warm the area, apply GTN and inject with hyaluronidase then massage. If you are fortunate enough to see complete resolution, they recommend giving 75mg aspirin daily for two weeks. If there is a lack of resolution they recommend immediate hospital referral to an Emergency Department of Plastic Surgeon. I find their middle box in the final row of the protocol confusing; if incomplete recovery occurs in my patient I will be referring them immediately to hospital!
I am not being sponsored by anyone in writing this post. I have written simply to improve the understanding of practitioners carrying out Dermal Filler treatments. Most of this post is simply the drawing together or others’ thoughts although some of it is my own thinking. If you’d like to challenge anything i’ve said here, please do on firstname.lastname@example.org
In that case, it may be fitting for me to edit part or all of this post.
Dr Michael Aicken of Visage Aesthetics UK LTD, Visage Academy & Flourish app.
We DID sell emergency filler packs ourselves but have decided to stop this as of 1st December 2015. We will no longer be replying to enquiries about these, but are happy to supply all of the information required for you to put this together for yourself.
Ask Dr Michael Aicken for some professional advice about either Botulinum Toxin OR Dermal filler, either as a patient or a practitioner.
1) Park SW et al. Iatrogenic Retinal Artery Occlusion Caused by Cosmetic Facial Filler Injections. The American Journal of Ophthamology; 154(4):653-662.
4) Expert Consensus on Complications of Botulinum Toxin and Dermal Filler Treatment. Inglefield, Collins, Duckett, Goldie, Huss, Paun, Williams (March, 2014). Part funded through an unrestricted educational grant from Merz Aesthetics UK).
This paper was not used in this article but is well worth reading to learn more about other side effects and complications of dermal filler: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3865975/