The regenerative properties of this minimally-invasive treatment lie in its ability to induce the formation of new collagen and elastin fibers (neo-collagenesis). The ability of microneedling to induce percutaneous collagen regeneration has been of great benefit to patients disfigured by acne scar depressions, burns, large pores, hyperpigmentations, uneven skin tone and those seeking anti-aging treatments. Medical microneedling utilizes needles with a depth of 0.5mm to 3mm.
Studies and articles have consistently documented the improvements in skin texture and tone post-collagen induction changes associated with microneedling in darker skinned patients, Fitzpatrick types IV to VI.
What is Medical Microneedling?
The technique is one which is performed in a physician’s office, as opposed with the invasive cosmetic microneedling which the patient can perform at home. The distinction lies in the needle length – 0.2mm to 0.5mm for home cosmetic microneedling, and 0.5mm to 3mm for physician Medical microneedling.
When performed correctly (preferably with stainless steel needles), the microfine needles of the roller penetrate the epidermis uniformly at a depth of up to 2.5mm depending on the manufacturer’s needle length. The creation of multiple micro wounds begins the cascade for wound healing, while preserving the integrity of the stratum corneum. Unlike other ablative aesthetic treatments such as laser resurfacing, the inflammatory reaction elicited with CIT is much less. After microneedling, there is rapid closure of the stratum corneum after 15 minutes, with little formation of scar tissue.
The uniqueness of healing with microneedling lies in the fact that the stratum corneum is preserved. Even more remarkably, is the fact that three major cell groups (the keratinocytes, fibroblasts and melanocytes) can all be positively regulated by this simple treatment.
Histologic sections have shown that when a medical needling device is used, the cells are neatly separated with puncture wounds of approximately 4-cell widths. The epidermis and stratum cornea are largely intact, with needle tracts penetrating 1.5mm to 2mm extending to both the papillary and reticular dermis. Six months post-procedure, an estimated 400% increase in collagen and elastin was observed histologically.
Wound Healing – Physical and Electrical
Healing has to occur after breaching the epidermal and dermal layers, leading to the release of multiple factors, including growth factors and cytokines. Key to controlling the severity of the inflammatory response and healing with microneedles seems to lie with the production of Matrix-Metallo-Proteinases (MMPs) and TGF-β3 during the remodeling phase.
Often overlooked in the healing of skin is the electrical component. The penetration of the stainless steel needles into the intercellular spaces creates a short-circuit with the electrolytes within the intercellular fluid. During treatment, approximately 200 needles penetrations occur per cm ² of skin. This induces a heightened polarized electro-magnetic field, and encourages electro chemo taxis with the cellular matrix. This is theorized to amplify the healing response.
The Benefits of Microneedling
The list of uses in aesthetic rejuvenation is impressive, especially so since it can be used on all Fitzpatrick Types I to VI. Microneedling can be used to improve the following:
Acne lesions and oily skin
Mild to moderate rhytides
Stretchmarks / Striae Distensae
Proposed Theory of Mechanism of Action for Hyperpigmentation Treatment
In darker skin tones, post-inflammatory hyperpigmentation (PIH) is common, and cosmetically displeasing to many patients. The hyperstimulation of the melanocytes in response to trauma and inflammation involves the interplay of multiple factors including cellular components melanocytes, keratinocytes, fibroblasts, and non-cellular components such as melanin stimulating hormone (MSH) and mitogen-activated protein kinase (MAPK).
It has been proposed that microneedling has the ability to balance and equilibrate melanogenesis and melanocytes dendritic formation by preserving the keratinocytes which is a key to signaling how the melanocytes behave. Keratinocyte preservation regulates the uptake of melanin pigment in a more uniformed fashion. The restoration of fibroblast function by microneedling is also proposed to control melanogenesis.
Microneedling offers physicians another safe avenue for controlling hyperpigmentation in darker skin toned when treating PIH.
Treating Fitzpatrick Types IV to VI with Hyperpigmentation and Acne
Treating PIH and mild to moderate acne cases with microneedling on dark skin can consistently yield favorable outcomes when performed correctly. Excellent results can also be achieved when patients incorporate a homecare regimen of a cosmetic home needling device and a mandelic acid-based product. Mandelic acid (Alpha-Hydroxybenzeneacetic Acid) appears to work very well for controlling hyperpigmentation in darker skin, most likely because its large molecular size does not allow for deeper penetration and irritation, and also this acid has known antibacterial and exfoliative properties.
Recommended Microneedling Protocol for Fitzpatrick Types IV to VI with PIH and Mild to Moderate Acne
Medical microneedling with 2mm needles, a series of six, every four weeks
Surgical grade stainless steel needles to encourage a favorable electrical trans-epithelial potential
A medical grade home skin care line incorporating green peeling oil, and/or another regimen of the physician’s choice for acne.
Daily use of sunscreen with UVA/UVB protection
Murad Alam, Ashish C Bhatia, Roopal V Kundu, Simon S yoo, Henry Hin-Lee Chan, Cosmetic dermatology for Skin of Color
Lance Setterfield, The Concise Guide to Dermal needling
Horst Liebl, Luther C. Kloth Skin Cell Proliferation Stimulated by Microneedles, Journal of the American College of Clinical Wound Specialist, Volume 4, Issue 1, March 2012, Pages 2-6
Dunkin CS, Pleat JM, Gillespie PH, Tyler MP, Roberts AH, McGrouther DA: Scarring occurs at a critical depth of skin injury: precise measurement in a graduated dermal scratch in human volunteers. Plastic Reconstructive Surg. 2007;119(6): 1722-1732.
Aust MC, Reimers K, Vogt OM: Medical needling: improving the appearance of hypertrophic burn-scars. GMS Verbrennungsmedizin. 2009;3:Doc 03
Kloth LC: Electrical stimulation for wound healing: a review of evidence from in vitro studies, animal experiments, and clinical trial. Int J Low Extrem Wounds. 2005;4(1):23-44.
Desmond Fernandes, MB,BCh, FRCS(Edin) Minimally Invasive Percutaneous Collagen Induction Volume 17, Issue 1, February 2005, Pages 51-63