Commentary on: Micro-Needling Depth Penetration, Presence of Pigment Particles, and Fluorescein-Stained Platelets: Clinical Usage for Aesthetic Concerns

I believe that this is an important paper1 that explores important questions about the popular mechanical “micro-needling pen”—a type of device for needling that to date is not adequately addressed in the literature regarding skin needling. The authors have done a difficult and rigorous investigation to show the best treatment methods and the clinical effects. I highly recommend this paper to everyone who needles skin, and I do have some comments that I believe are pertinent. I believe that the most important fact established by the authors is that with pen type instruments, one cannot rely on the settings of the needle cartridge when selecting a needle length more than 1.0 to 1.5 mm. It is important for people to understand this and recognize also that 1.0 to 1.5 is a very effective depth to achieve good results as shown in this paper. The clinical photographs confirm that shallower needling at 0.5 to 1.0 mm (in fact minimal or no bleeding) gives less evidence of collagen/elastin regeneration and, in my opinion, show the effects of the enhancement of the cosmeceuticals used. On the other hand, with deeper needling at 1.5 mm, where one would expect to see bleeding, the results are more profound. The histologic photographs are excellent and instructive, and the clinical results of using various needle depths are very useful. I found the studies on massage after needling to be interesting. However, I did not understand exactly what massaging “in the same pattern and frequency as performed during MN” means. Do they mean that the Dermapen is used again? Surely it should replicate what we do clinically? The studies on radiolabeled platelets is very instructive in showing that they are well absorbed into the dermis and then disperse. It is my impression that the variability of results from needling could be explained by the variances of platelets. It would be interesting to see if there is any relationship between the platelet count and the degree of improvement. There is an important limitation of these studies on massaging, because generally needling a face takes approximately 40 minutes and then only after washing can we apply anything to the surface of the skin. It would have been a more useful study to show what happens to fluorescein or platelets that are applied to the skin 40 minutes after needling. The study would then have greater clinical significance. The question is also whether one simply applies any cosmeceuticals directly after needling or whether we clean the skin first. Since 1996, I've apply the selected cosmeceuticals immediately after cleaning. Their findings are not confined only to mechanical needling of the skin. The fundamental fact is that the needle hole and the depth of the hole is what determines the result. The method, whether it is electro-mechanical or a manual roller or a stamper, will give the same results if the skin is penetrated to the same depths. It should be questioned whether a finer needle (eg, gauge 33) will provide the same results as a somewhat thicker needle, but we cannot be certain. I still wonder whether fewer, thicker, and deeper holes actually might have benefits over the shallower but very closely needled skin that we see from mechanical devices. I do question the technique of testing the needle depth. By needling skin in situ on the face, we would have a more realistic understanding of the depth of penetration. The depth obtained by needling stretched skin on a firm board probably replicates the maximum depth possible on the forehead but not on the softer areas of the face where the needles would penetrate less. The tracts are more difficult to find but give us a better understanding of how deep the needles go. When the skin is stretched on a firm corkboard, the needles most likely penetrate deeper. On the histology (the authors' Figure 1A), the tracts are tortuous, and the stretching of the skin probably distorted the normal conformation of the skin. I cannot think of another way in which to interpret this. I validated the pigment penetration by using Indian ink, which is relatively coarser than the ink used in this study, and the depth of penetrating was approximately 2.0 mm by using a 3.0 mm length needle Roll-CIT. I was more interested to know whether a substance applied to the surface was left on the skin, was not washed off, and would penetrate into skin. I only massaged with my brush for a short while, and then I allowed the ink on the surface to dry. The ink penetrated far more extensively than the actual needle hole, so I believe that is a lesson we need to bear in mind when we apply anything to needled skin. This is also my interpretation about the “disappearance” of the labelled platelets. This study shows very nicely that with time more of the topically applied product penetrates deeper into dermis with longer needles. Short needles that do not penetrate through the epidermis have basically no better effect than very short needles that penetrate only the stratum corneum. When reading the description of the actual needling process, I became concerned, because as described it seems far too intense with 20 passes vertical, 20 passes horizontal, etc. We need to know how big an area is treated at a time. Generally, we treat defined areas (eg, the size of half the forehead) sequentially to optimize the topical anesthetic. Because the patients in this study could return to work the next day, we know that the density of the holes could not have been too intense. I worry about this detail, because since the introduction of the pen-type devices, I receive emails about “abraded” areas of skin that do not heal well. I believe that the potential for overtreatment and excoriation of the epidermis cannot be ignored. With rolling devices, this is not a problem. I think that visual demonstration is very important to avoid overtreatment. An even distribution of the rows without a streaky appearance is also preferred. Including a photograph of the skin immediately after needling, even with the blood still on the skin, could have been instructive to understand the degree of needling. The risk of “overtreatment” and excoriation of the epidermis becomes a real danger when trying to do skin needling at 2.0 mm or more with these vertical mechanical needling devices. The needles have to “glide” over the skin while they penetrate, and it becomes difficult to get vertically oriented needles to penetrate 2 mm and to be fully withdrawn as one glides over the skin. If the needle has not been fully withdrawn as one moves, then the needle could damage the epidermis that is only 0.2 mm thick (ie, just 10% of the needle length). The mechanism of skin penetration to needle the skin safely with a mechanical device needs to be understood. Skin resists being penetrated and there is friction on the needle surface both going in and coming out of the skin. This can be seen with slow-motion, extreme-close-up videos. As the needle impinges on the surface, the skin gets pushed down and then the needle penetrates to its “dialed” length and then starts to be withdrawn. Friction starts to pull the skin surface upward and ultimately the needle exits the skin. The timing of needling sessions in this study at one session every 6 weeks is a timing regime that I abandoned approximately 12 years ago. We now recommend that by 5 weeks, one should complete six sessions. Aust et al2 first showed that TGF-beta 1, 2, and 3 have an exact opposite pattern of activity compared with what Ferguson and O'Kane3 have shown.TGF-beta-3 remain raised for approximately 2 weeks after skin needling, whereas TGF- beta-1 and 2 have a very short appearance and have disappeared by 2 hours. Zeitter et al4 tested the controversial matter of needling at intervals of only 1 week and found superior results. Zeitter has in fact confirmed our research in Cape Town that shows that by doing the sessions at shorter intervals, we have better results after the same number of treatments done at longer intervals. I think that the age distribution in this study is a lot older than we have in our clinics. We have found that an increasing number of younger men and women are opting for micro-needling as an age management regime. Aust et al2 looked at IL-10 and MCR and discovered that in needling, the MCR is down and the IL -10 is raised, which they believe favors lightening of the pigmented marks and avoids postinflammatory hyperpigmentation. IL-10 is normally low and the MCR is raised in posttraumatic hyperpigmentation. We have noticed that some people prone to pigmentation go through a phase after needling for approximately 3 months in which they believe that the pigmentation is worse, but this fades away and to date we have no patients in whom the pigmentation was permanent in our experience covering more than 2000 patients. I have never routinely used antiviral prophylaxis. I personally have a tendency to develop herpes labialis, and needling does not seem to provoke an attack. I have needled my face more than 70 times, and only once did I get a “cold sore” a few days after needling. In my experience of directly and indirectly needling over 2000 patients, a herpes infection after needling has not been a problem and has occurred so infrequently that I believe prophylactic treatment should not be given. In people prone to herpes labialis (such as myself), we only treat when necessary, and I use a once-only application of a cream of TCA at 2.5% that I have formulated. That stops the herpes immediately. The author declared no potential conflicts of interest with respect to the research, authorship, and publication of this article. The author received no financial support for the research, authorship, and publication of this article.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.