Movers and shapers
Dr Pierre Nicolau looks the characteristics of dermal fillers and discusses his experience with polycaprolactone
At the beginning of 2000, we started to see a lot of complications with fillers. It was surprising that there were no real studies of the biological affect of fillers in the body. We know that anything we place within the body has the potential to trigger a foreign body reaction to isolate or eliminate a potentially dangerous element. If what we place in the body is recognised it will stimulate a reaction, but if it isn’t, then there will be no reaction.
This is the same for fillers—some are designed to fill while others to stimulate and fill. The aim of fillers is to bring volume, but also to create new tissues—mainly a collagen matrix for a filling which will last through the produced collagen.once the product has disappeared
For these cases and for these products, the biological reaction is sought after ahead of the ones that are designed only to fill—the so-called volumisers. These volumisers bring injected volume with allegedly no reaction. Any reaction will be unfavourable, as the product has not been designed for it.
To have a favourable reaction, a filler must have several characteristics. The particles of the material have to be more than 25 to 30 microns to avoid phagocytosis—one of the first active reactions around the product. The particles have to be spherical as this leads to less inflammation, plus have a smooth surface as this is proven to mean less enzymatic activity. Eventually we would like to see a positive electric charge on the surface, to have a better reorganisation of the collagen bundles.
It’s extremely important that the particles do not degrade since this will change the physical characteristics of the product and will trigger a second reaction. It should also not migrate, or be displaced. Migration is caused by weight or muscular activity, while displacement is an active change of position, mainly through phagocytosis. We have seen a lot of problems due to the permanent foreign body reaction which is within the collagen capsule.
Non-permanent fillers will change with time and that will modify two very important characteristics—the size and volume. If they become smaller, less than 25 microns, a second phagocytosis will be triggered and maintain the inflammation. Changes in the spherical shape and the smoothness will trigger a new inflammation.
The surface of the product has a trigger surface area below which there is no body reaction. However if you augment the surface of contact just slightly you can trigger a very strong inflammatory reaction. A product that becomes porous, will tremendously increase its surface of contact. This explains why we sometimes have very acute inflammatory reactions for up to six months without any apparent reason.
Any inflammation through these mechanisms will persist for as long as the product particles are present.
Inflammation means the body will produce a collagen, which is a protection. A type-3 collagen, like scar tissue, is produced very fast. There are 28 or 29 different types of collagen in the skin, which contains mainly type-1, short and thick, but ‘immature’ collagen has an imbalance with more of type-3, which is long and thin, fibrotic, scar-like tissue
Most injections in the superficial tissues—dermis and sub-dermis- will lead to fibrosis and very rigid looking skin. And there is no evidence that this type-3 will be gradually replaced by type-1. The half-life of collagen is 15 years, but that does not mean the result will last for 15 years or 30 years, rather that changes to skin structure will be maintained for many years.
When the product does not change in shape or volume, you have the same type-3 collagen reaction and once the product is totally encapsulated, that will stop the inflammatory reaction. There is then time to produce new type-1 mature proper soft collagen. However if the product starts to degrade and change ots morphology, it will trigger an inflammatory reaction again.
A histological study shows that after nine months and 18 months with this type of material, you get the production of type-3 first and then gradually you get the production of more type-1 mature collagen than type-3. The final collagen is of a good quality and not just an immediate protection against a foreign body.
A very interesting study by Maria Khattar, a dermatologist in Dubai, compared a polycaprolactone product with calcium hydroxylapatite. The first case was injected with 4.5 cc of calcium hydroxylapatite, and after three months 50% of the volume injected had disappeared. The second case had 1.5 cc and after three months 60% of the volume disappeared. The third case had almost no product left at seven months.
She did the same with polycaprolactone. Up to 10 weeks saw a 48% increase of the injected volume of 4 cc. 1 cc injected saw over 50% increase at 20 weeks. In the chin area, which is not very easy to fill, there was 21% increase at three months. For most patients it is around a 20% to 30% increase. These are very small volumes and you need very little product because you know it is going to increase and there is no need to over correct.
Volume and bio-stimulation
So do we want volume? Or do we want bio-stimulation? What for? And where? The answer is in knowing how the different elements are involved.
We know there are bone changes and they can be treated mainly by deep injection at the bone level to compensate for the changes. It’s very important that you don’t compensate the bone by changing the skin and fat. There are several layers of fat in the face including 57% superficial fat in the cheek. 43% is deep fat so we have to think about that, because this superficial fat is equivalent to the body’s superficial fat under the skin.
This fat does not really change with age, it changes with weight. If you put on weight, your face will fill with superficial fat. Deep perimuscular fat, diminishes with age, not the superficial, hypodermis one.
The role of the muscles is also very important. We thought for a very long time that muscles would relax with ageing. We now know that this is the opposite. It is contracture that displaces the deep fat and to compensate for that we have to put our volume at a deep level to reposition these displaced deep stretches.
With sub-dermal improvement we do not want to change normal anatomy, so do we really need volume in the superficial layers? If you inject the filler in the sub-dermal plane, a smile would cause the fat there to just lift up with the movement and then it would come below your injection side. But in some areas, there is no deep, bone plane to support the correction. so sometimes we do need to inject superficially. In the hypodermic fat. But his should always done with very small volumes not ti change the normal anatomy.
Occasionally you get protruding veins in places like the temples. With strong veins you have to be careful because you might get a block which will last for quite a few weeks. This is very unpleasant, so in these cases I would tend to do a deep injection.
One lady asked me if I could do something for her nose and with 0.2 ml of polycaprolactone in the tip she had a striking improvement, with this very little product. This result will last a long time. I cannot obtain this result with any other product because none of them are mouldable and easy to inject like polycaprolactone.
With hands, you have the tendons in the deep layer, the tendons and veins in the intermediate layer, and a superficial fibro fatty layer. If we manage to inject superficially to the veins we are very safe and there’s no pain because there is no structure. I either use a 22 or a 25 gauge cannula and I inject with the product which is either not diluted or just mixed with 0.2 to 0.3 ml of lidocaine . This has great, instant results, which are very interesting because you can get a very light thickening to hide deeper structures.
When no volume is needed, we use the pure bio-stimulation that we get for the collagen, which is to improve the skin quality. A lady I treated for her lips did not want toxins, peels, or laser treatment. I injected a total of 0.4ml of polycaprolactone subdermally in the upper lip, She saw fantastic results after three months. She said she was so happy with the results she didn’t want to another injection at 3 months.
After six months the results are still incredible and no other product has given me similar results.
For a volumiser, I want good volume, something that is going to stay where I inject it and be mouldable eventually. I want a product which is not displaced and that will spread if I have to massage to prevent clusters or nodules. Fibrosis is a real issue, because if you get fibrosis in the fat layer it will show and block the face creating a terrible mass appearance of very tight immobile skin. This is where for me this product has been a complete change.
Dr. Pierre Nicolau is a past consultant Plastic Surgeon at the University Hospital Saint Louis, in Paris, and runs a private clinic in Spain