The Art of the Injection: A Masterclass in Safety and Precision
We begin not with a needle, but with a fingertip. The most important tool in any injector's kit is not a syringe or a cannula—it is the sense of touch. The first step is to find the facial artery, not to avoid it because we are injecting something that could cause a blockage, but because we respect its proximity. We trace the boundary of the vessel, then we feel for the fullness of the product already there. In this case, it is Harmony CA, a blend of calcium hydroxyapatite and hyaluronic acid. The goal is to reduce the bulk by eliminating the hyaluronic acid component. We can feel it clearly on one side; the other is harder, but the sensation guides us. The needle pops into the area, and we grip it before injecting. Accuracy is about what your fingers tell you, not just what your eyes see.
There is a lump here, but it is small. The true measure is aesthetic shape. If the lump does not cause a shape we dislike, it does not matter. We move with a little oscillation as we go in, wanting to cross over any small boluses. Then we come to the temples—a place that worries many practitioners. There is a great debate in our industry: needle versus cannula. I have researched this extensively for a conference, gathering all the data I could find from around the world. I looked for correlations between the instruments. Most people will tell you cannula is safer, but I noticed in my own clinic, where I had a mix of doctors using both, that we were getting complications from cannula. Nothing severe—just people needing reversals or mottling on the skin. No one ever had a true untreated vascular occlusion that caused a scar. But all the complications we saw were from cannula. On social media, you will be judged for using a needle, and people will say it is more dangerous. Yet there is no data anywhere in the world that supports that. In fact, cannula is massively overrepresented as a risk in the temple. It is more about superficial blockage to the scalp than deeper vascular occlusions, and I cannot find any documentation of a complication from a hyaluronic acid needle on bone technique anywhere. I have heard there might be one somewhere, but I cannot in good conscience rely on the statement that needle is safer than cannula in this area based on what I have read. So I still use needle on bone.
Layering Safety: The Philosophy of Injection
Now I spend a long time feeling for an area where I do not feel a pulsation. There are little pulsations right where I might inject—those are not the ones to worry about because I can feel them. I keep looking until I find a quiet zone. I mark that spot. Safe technique is about layering safety. It is never about one thing. It is not just about feeling for the vessel or using a reversal product. It is about all the things together, each step dividing your risk. Remember, there are two layers of defense here. One is feeling for the artery pulsating. The other is injecting at a different layer—a deeper injection is underneath almost all the arteries, with the exception of the deep temporal arteries, which are very small and disappear closer to the bone, at least on all the cadavers I have seen. So I aim to be relatively superior and lateral to any artery, and deeper to the artery.
I choose my injection point where I feel nothing. Now I choose my product—a reversible one. I attach an aspirating ring to make the next safety check easier. I use an unprimed needle, which means there is a tiny bit of space in the needle itself that allows blood to flow back very easily. This product aspirates very well. Notice the stability of my whole body. My elbow is pulled in to keep everything stable. This hand stabilizes the patient's head. My other hand stabilizes on my thumb, so only my finger and thumb control the needle. That gives me the most control. I go gently into the right plane, touch periosteum very quickly, then aspirate. There is now negative pressure in the syringe. I can oscillate, which improves the sensitivity of my aspiration. If I have impaled a vessel, I will at least get a hematoma forming. Then I can aspirate that. I will know I have gone through a vessel and know not to inject. I give it time—that is the hidden variable. Give it time for the product to flow, for the blood to flow in. All of that is negative. That gives me the confidence to slowly close my aspiration. I can do even more sensitivity improvement by aspirating and moving with even less negative pressure, just in case I have sucked a vessel closed—that is one of the criticisms of aspirating, that you could suck a vessel completely closed. I limit that by closing the volume slowly to equalize pressure slowly. Now I watch the patient's response as I inject. Any sign of discomfort, I stop. I watch the area fill, the patient's response, the surface of the skin. Repeat the same again. Feel for any vessels. It is very important to go into the moment. You cannot be worried about time. You cannot be worried about anything except what your fingertip is feeling.
The Cannula Approach: When and How
Now we move to the lateral frontal fat pad. There is a little transition between the frontal part of the forehead and the lateral aspect. This fat pad is slightly shrunk, which is very common, especially in slim people. I want to replace volume here, under the frontalis. Although it is a cannula treatment, I still do not want to go through a vessel on the way in. So I find a quiet zone and create a little pilot hole. The good thing about pilot holes is that if you go through a vessel, you will know because it will bleed. Sometimes the pilot hole needle will bleed straight away—the blood comes out the top. To replace a fat pad over a relatively large area using a needle would involve multiple individual injections in the upper part of the face, which is higher risk. My total risk goes up, the number of bruise points goes up. So instead I use a blunt tip cannula. I can go all over this area without as much trauma, and I get the benefit of safety—about 1 in 40,000 chance of vascular occlusion compared to 1 in 6,000 for needle.
For this technique, I need to be under the frontalis muscle. That means I have to follow the path of the pilot hole all the way until I touch the deeper tissues. I go through the dermis, the hypodermis, the fascia of the muscle, the muscle itself, and into the loose areolar tissue. Then I touch the periosteum. Once I am at that level, I gently wiggle the cannula with a slight bend so it slips underneath those layers into the loose areolar tissue. If the patient raises their eyebrows and the cannula does not move much, that is a good indication that I am under the muscle, not in it. I move very cautiously, looking for my position. I want the cannula to move freely. If you are in a vessel, it is also tethered. So this free movement is part of the safety. I also want the product to come down and stay deep. I turn the bevel of the cannula facing down. There is nothing wrong with aspirating. I have a negative pressure now. I could move all the way along here. If I was in a vessel, there would be a chance I would get a flashback—I have had that at least once. The non-bleeding pilot holes are also part of safety. If I had impaled a vessel, I would have seen bleeding. As I insert the cannula gently, that reassures me I am not in a vessel. This movement without injecting reassures me. When I inject and see tissue rise, I close off the aspiration. That little fullness that appears tells me the filler is in the skin, not in a vessel, or at least under the muscle. I can trickle product in when there is a sensitive spot—it has a little numbing effect that can help.
Choosing the Entry Point
How do we choose an insertion point for the pilot hole needle? You want to find somewhere that gives you access to two things. First, the two-dimensional spread of the product. If I chose an entry point here, it would be much harder. Or up here, harder. So I choose an entry point that will allow me to reach all of this section. Second, the entry point needs to give you a three-dimensional element—the depth you need to go to. I want to get underneath the frontalis. There would be no point making a pilot hole that was lateral to the frontalis or into the temple. I want to go into the frontal bone. And I also want to go somewhere where there is no blood vessel. Look at that—there is one. The pilot hole can be used as almost like aspirating. It is a safety check. When you get a little flashback like that, it came as I was pulling out. Arteries are very rarely on the bone. They are typically above the periosteum. What happened with this flashback is I went all the way in, the angle was not as tight as it could have been, so I went further into tissue and I think I impaled something. I touched the periosteum, did not get a flashback, then as I came back out, the needle filled up with blood. That is how you detect the presence of a vessel. That is very helpful information—I am not going to go in there again. I am not going to put my cannula in there. I also hold that point where there was bleeding. If you hold it for a minute, it will probably heal up and she will not even get a bruise. Reacting to it and holding it is the easiest way to decrease bruising wherever you see bleeding, whether it is coming out the top of the skin. Such an easy tip that will stop us from worrying for the next week about a black eye and all the things that can cause massive distress to patients. They are really just bruising, but they are very upsetting.
I will go back to finding a better place to do a pilot hole. I will not go through the same entry point. Very simple rule of thumb: Einstein famously said, "The definition of insanity is doing the same thing twice and expecting different results." So always do something different when something bad happens. It does not matter what you change, just change at least one thing. The easiest thing to change here is to not use the same entry point. I go back, feel once again for a quiet spot. I go in lateral to where the first injection point was. I also change my angle—go in slightly steeper. Touch periosteum, little oscillation, back out—no bleeding that time. Unfortunately, because there has been a bit of bleeding, it can be a little more sensitive here due to inflammation from the blood. I remember that shift: I went for a slightly steeper angle to be further away from the initial place. I repeat that. I gently wiggle the cannula down, trying to cross all these layers before I touch the periosteum. When I feel I have got to the deepest spot, I create a little bend in the cannula as I try to line it up with the layers of tissue. If the patient looks uncomfortable, which I detected with a little bleed, I try a different position. I try to get in with minimal discomfort. She is feeling it a bit, so I aspirate and do a little squirt of product which has numbing cream (lidocaine) in it. That gives us a bit of space and a numbing effect. It opens up the area a bit. Considering she is very good generally with injections, this seems to be a sore spot. I want to get it done. Bevel down, up to here. Moving the cannula reduces risk.
Managing Discomfort and Patient Psychology
I do not like it when it is uncomfortable for the patient. It is a constant throbbing, a bit painful. But I acknowledge that acknowledged pain reduces the pain. Just her knowing that I understand can help. I am now aiming for a more inferior point. I made this entry point so I could get across all the areas, but this is a slightly harder area because I have to go more inferior. My pilot hole is at this angle, so I still need to go down to the periosteal layer. When I pop through that, I can rotate. I do not like the tightness here. When it is too tight, it gives you a bit more room that you might have popped into a vessel. So I want to check the movement. I aspirate, move again, watch for a positive. This product does aspirate even with a 27-gauge cannula—I have tested it. I hold 10 seconds of negative pressure, close off slowly, compress the vessels here just in case I was in one. I can shape the product to help me avoid unnecessary passes. I mold it to where I want it to go. I have not quite achieved what I know I can. The best way is to make another entry point. It is too tricky crossing this way where there is a shadow. I need to enter slightly differently. My thinking is that this is a fracture line in the skin. If you are parallel with it, it is far easier to correct than if you are perpendicular, which is how I was. So I focus here, and after correcting that, this area becomes more obvious. I do just a little bit in this area—I do not actually need to get underneath frontalis for this. Gently in, aspirate, move back and forth along the passage I want to fill, looking for any positives. Then I slowly trickle a little bit in, not very much—0.5 ml. That gets the little shadow.
The Glabella: A High-Risk Area
This area just here at the glabella is often where there is a branch of the supratrochlear artery. It comes up in this crease, usually deep on the bone, then rises up and re-emerges about 2 cm up in the middle layer. Then as you get to here, it becomes superficial with small branches. In theory, this would be a great place to cannulate the artery if I wanted to. The most dangerous way to inject would be to come straight down like this and go as deep as I can—that might actually get into the artery. So we want to do the opposite to reduce the risk. There is a small chance of this artery, which is connected to the eye, potentially filling with filler and causing blindness. They say one in a million. I do not want to rely on it just being unlikely. I want to reduce the risk in as many ways as possible. I would not do this procedure if I thought there was a chance that you could go blind. Statistically, there is always a chance, but that can happen for all sorts of reasons not even related to filler. I want to take every opportunity to reduce the risk. The first thing is depth: we need to be as superficial as possible. In the dermis, the artery is not there—the artery is on the bone. So intradermal injection. Number two, we use very low volume. Even if I was in the artery, it would not be enough to block the whole vessel. We would only get a superficial vascular occlusion on the forehead. Low volume is the easiest next thing. We aspirate to check if we are in an artery before. I also compress the vessel from underneath by simply squeezing here, so that even if I was in a vessel, it would not be able to flow in that direction. By far the most helpful thing is small volumes and checking in between because you have to put a significant amount in to cause a problem. Most cases of blindness actually come from huge volumes used in surgery to inject fat, not filler, and it is very different from hyaluronic acid. But take every opportunity to lower risk, and you will be in a much better position over a career. I am not even talking about one patient. I would not do this procedure if I thought there was a chance of getting one patient in a career, and I do not believe that with how I inject.
Entry point very superficial. I need to guide my injection to stay superficial the whole way in. I compress underneath that line to stop any blood flow in that direction. I get a little positive—a dark flashback, probably a vein, not arterial. So I come out from that. It stopped me injecting, which is the whole point. Why do I get so many bits that bleed? I do a lot of things to increase the chance of getting a positive. The positive is good—it tells me I am near a vessel. It is a screening tool to detect passing through reasonable-sized vessels. Sometimes you pass through three small vessels that would never occlude anyway, and you get a positive flashback. But my approach is it is better to not inject three times when it was not going to cause any problem than to inject once where it might have. It is a way of detecting how close you are to a vessel, even if you are over-egging it.
Different entry point. Keep my depth the same—superficial as I can. I tent the skin consciously to stay away from vessels. Aspirate, oscillate. Hard to find this point pressure. There it is—my safety check for pressure. Still negative and movement. Then tiny volumes—0.025 ml, very low volume, not enough to block a significant vessel. Check for the refill, which is normal. There are two little bleeds—might be a little fullness. I make sure it is not filler by pushing on it. If it looks better and then refills, that is swelling from the injection point, which is by far the most common cause. I usually point away from the eye to lower the risk, but now I need to do it this direction. I do a different approach: I want to elevate the dermis out of the way because the artery stays on the periosteum underneath. It is never in the dermis. I point the needle from this angle, keep my depth superficial, get that little depth check, aspirate, compress the vessel underneath, move along that path, no positive aspiration. Then a little whisper of product. It comes out, which tells me I am not in the artery. Not the best use of product, but some of it will be lifting. It gives me assurances I am not going into a vessel. That looks better.
Midface Support and Jawline
Now our next goal is to support the midface through a couple of lateral injections. There is a reasonable connection. I have some optimism that we will get a little lift. I do not have a lot of space for a lot of product because there is already good volume, already heart-shaped. But we go in that direction. If you are aiming for lift, you want to be in the upper half of the zygoma, following the defining line. I typically start at the angle, but I put just a tiny bit of focusing product here—not high volumes. I feel with my finger the inferior part of the bone. Go down, touch periosteum, aspirate, 0.1 ml. That is it. I would usually do more, but it has already been partially done. I go more posteriorly through the same entry point. The key is the upper part of the zygoma. I am decreasing the number of entry points and building up on top. Another 0.1 ml—surprisingly effective, very small amount. I do two injections here, then go a little further back. This is about as far back as you want to go. Once you get towards the more temple posterior aspect, it is not that helpful. I need to blend it in. It works so well in terms of creating shape that I just want to blend it slightly.
Now that we have corrected the temple, there is room for lateral cheek. This is relatively straight, so the heart shape has more access. I do the same again: aim for a little focusing of the cheek and some lateral projection. Try to use the same hole. Touch periosteum, aspirate, oscillate, 0.1 ml, come out. Rotate, aspirate, oscillate. The supporting finger feels for the inferior border of the zygoma. Angle of entry is from above because I am doing everything I can to create a little lift. A little sensitive. I get another positive—a pretty big flashback. That is an unusual place to get a positive. So you are now a bit above average. But if you think about it, a healthy cardiovascular system with lots of blood pumping through for years, slim—there is basically more blood vessels to fat ratio in your face than there would be in most. This means there is a high chance I will hit a vessel. It is actually super unusual to get one there, though. But it is great because it means my safety test works. From a training point of view, it is great. It is great compared with if I did not do the check. Especially when it is unusual to get one there—it is just a probabilistic thing. Most arteries are not there, but it does not mean it is wrong; it is just a variation. Because of the tiny drop of blood in the product, and because the patient was jumpy, I lost my nerve and decided not to inject. It is helpful information. Do not suppress anything. I think it does hurt more when you go into a vessel, so if it hurts more, that is useful to know. The combination of the positive and the jump made me think twice.
The Gonial Angle and Chin Support
Now we work on the gonial angle as a place of support for the midface. I look for the shape of the bone underneath. It is a positive indication to treat this when you can. You ask yourself where the bone is. You follow the track of the skin—you might think it is somewhere up here, but that is because of a little gel fat pad or product that is here. As it tracks up, it creates a shape that makes the jawline look shorter. But the actual jawline is significantly lower down. If I can get this to rise up, you will see better structure, and it also makes this fullness area look less full—the eye is now framed differently. I feel for the actual natural position of the gonial angle. Put a finger underneath it, then enter and try to hit right on the angle of it. It is not usually a deep injection because there is no fat on top of it. Aspirate, little oscillate, close off aspiration slowly. 0.2 ml. That is the gonial angle. As you can see, it is not the defining point as is. Notice my needle is pointing slightly upwards—not 90 degrees, or you will often miss the bone. Aspirate, oscillate, inject. Support from underneath and behind. 0.2 ml is a common amount. For someone slim, it is still significant. I never go by averages; I go by what I see.
I ask the patient to do a big smile. I wonder about using filler in a different way to stabilize from underneath. If we go underneath the jawline, it will stabilize the chin so when you smile, it is not as easy to pull down. It can bridge some of the gap, but because it is under the jawline rather than lateral, it will not make you squarer. That is something we could do that would combat both things. We can also try toxin, but basically when you smile, I see this little lip, and we can fill that separately. It means the chin does not disconnect because there is a sharpness to it.
For the viewers at home, if you put your chin up and look away, this is our enemy—this fullness here. We have put a bit of hyalase in that will hopefully reduce it. Then what creates the definition is both the dip on this side and the dip on this side. Sometimes there is rotation of the chin. She pointed out that when she smiles, her chin gets pulled down, which highlights the pointiness of the chin and the inward curve. So I go in a slightly unusual place—more inferior to support the chin and stop it moving, with a very low volume supporting injection using a cannula to soften this little space. But we are taking into account that hopefully it will shrink because we have put the reversing agent here, which takes a long time to work. It may have already helped. You can sometimes put a full ml here for augmentation. This is going to be 10% of that, maybe 15%. Just to link it, stabilize it. And because she is concerned about this fullness, here is the tip: if you create your pilot hole right on the apex of the jaw and you get a bruise or swelling on the entry point, it makes it look worse. So even though the filler is not there, it is a good opportunity to not do that. Enter slightly anterior to it, so that you are not going to make it look worse, even if it is just for the mirror. Where there is anxiety, there is room to increase it. So I go all the way down and underneath the jawline, not lateral to it where it could make it squarer. With my supporting hand, I start to line up the tissue to where I want it to be. This little push squeezes the tissue down, gets things in alignment. I want to be underneath the projection of her chin. She does not want a bigger chin, so I am underneath that point. I am unusually putting pressure on it to get it to flow under, rather than on top, which is what I would normally do when trying to get a chin to project out. This is the opposite. There is a bit of connective tissue. This cannula pushes up against it. That was only 0.1 ml, very small amount. It is doing a good job though. I can see the difference. I am making sure none of it is adding to where she does not want it.
Intradermal Techniques for Dynamic Lines
There is a little shadow here. Not related to the treatment we tried to reverse—it is the type of thing you see more as you lose volume. I feel very confident we can improve the defining line of the chin without doing what she is worried about. I look for the position of the cannula, just looking for where these lines are, seeing if I can bridge them. I try to put a tiny bit of resisting product. These are all vectors that resist movements. So I create a brick-like pattern with intradermal injections—0.025 ml each, stacked across. All of these are 90° to the force created by the smile, which is why it resists. It is just strengthening the skin slightly. You cannot put much or you see the filler. This is an immediate medium-density product. Over the course of a treatment, there is a reasonable amount of product spread out. I ask her to smile again. Because I am so near the surface of the skin, I do not aspirate here. There are no arteries at this level, as long as you can see the skin a little blanching where it goes white as you go in. I am also putting very tiny amounts per pass.
These little lines here run underneath the chin, sometimes called chin strap lines. They are actually remarkably one of the easier lines to treat. You need to be superficial in the dermis. A fine line product like Juvéderm Volbella works best. If you go under, you just do not get the difference. So the angle of approach has to be superficial—enter at about 20 to 30 degrees. This is not a true chin strap line, but we could improve it. The patient asks if most of that around the area where we put the dissolver will disappear again. I explain that there should not be any in exactly the same layer of the skin in that area. In theory, they always say if you do the treatment the same day, there is a chance it will dissolve, but I have dissolved many lips, for example. Even if you dissolve someone's lips on one side of the boundary of the muscle where it inserts on the other, it does not pass through easily. These injections are relatively deep, not on the dermis. So the depth makes all the difference. I am in the dermis, so there is relatively high resistance going in. That is the most effective place to improve these little oral commissure lines. I want to be parallel to the line directly underneath it, just supporting from underneath. This little injection supports the oral commissure close to where the boundary where the two halves of the lip meet. Superficial injection.
This little central line here often comes out better than the other lines, surprisingly. But it is unlikely to totally disappear. It is a bit of a pinchy one. I apologize for the discomfort—this might be a low point. I put some anesthetic on, but we get it done quickly. I want to stay as superficial as possible, in the dermis. I aspirate and inject on the way out. I apologize—it made her cry. But it made a great difference, so it will be worth it. I work at a slightly lower layer with a very gentle product, just to link these two areas up and blend this in. I want to be in the superficial hypodermis, with the cannula facing up. I am just trying to feather in. The little natural ripples that occur during dynamic movement are just dampened a little bit. It is like having a small extra layer of fat. This line here is still framing some of this, so I try a bit harder to get that with a little needle. You can tell when you are in the dermis when it comes out.
And so, by layering each step—feeling, selecting the right instrument, aspirating, using low volumes, choosing the correct depth, and always being present in the moment—we transform a procedure into a practice of safety, empathy, and art. Every injection is a story of risk divided, a story of the fingertip guiding the needle, and the wisdom of knowing when to stop and when to proceed.