according to Catherine M. DiGiorgio, MD, MS.
Dr. Catherine M. DiGiorgio
During a virtual course on laser and aesthetic skin therapy, Dr. DiGiorgio, a laser and cosmetic dermatologist at the Boston Center for Facial Rejuvenation, provided a state-of-the-art update on microneedling, a procedure in which microneedles are rolled over the skin to create epidermal and dermal microwounds.
“The depths are adjustable and it’s purely mechanical: no energy is being delivered with these treatments,” she said. “The hypothesized mechanism of action is that microneedling creates microwounds which initiate wound healing to stimulate new collagen production. This breaks apart compact collagen in the superficial dermis while stimulating new collagen and elastin,” she explained, adding that it is also hypothesized that this “stimulates growth factors that directly impact collagen and elastin synthesis.”
Conditions that have been reported to be treatable with microneedling in the medical literature include scars – especially acne scars – as well as rhytides, skin laxity, striae, melasma, and enlarged pores. Microneedling can also be used for transdermal drug delivery, although it’s far inferior to microinjection of medications. Contraindications are similar to those with laser surgery, including active infection of the area, history of keloids, inflammatory acne, and immunosuppression; and it should not be performed on the same day as neuromodulator treatment, to avoid diffusion of the neuromodulator. Herpes simplex virus prophylaxis is also indicated prior to microneedling treatment.
Many devices are available for use, including fixed, manual needle rollers and electric-powered pens with single-use sterile cartridges. The devices vary by needle length, quantity, diameter, configuration, and material of which the microneedles are made of. The needle length is not reliable for penetration depth, especially when greater than 1 mm. Treatment guidelines vary based on the area being treated.
“You put tension on the skin and apply the device perpendicularly,” Dr. DiGiorgio said during the meeting, which was sponsored by Harvard Medical School, Massachusetts General Hospital, and the Wellman Center for Photomedicine. “It should be performed in quadrants, and I prefer to treat in cosmetic units. The endpoint is pinpoint bleeding versus deep purpura. Ice water–soaked sterile gauze can be applied after treatment and skin care can be resumed in 5-7 days.”
In an effort to compare the efficacy and safety of the 2940-nm Er:YAG laser and microneedling for the treatment of atrophic acne scars, researchers in Egypt performed a randomized, split-face study in 30 patients. Study participants were evaluated by two blinded physicians at baseline and at 3 months follow-up. Both modalities showed a significant improvement in acne scars, but those treated with the Er:YAG laser showed a statistically significant greater improvement (70% vs. 30%, respectively; P < .001). Histology revealed a significantly higher increase in the mean quantity of collagen fibers in the Er:YAG-treated patients, compared with those who underwent microneedling, but patients in the microneedling group experienced less erythema and edema. Pain scores were significantly higher in the microneedling group compared with the Er:YAG group.
In a more recent study, researchers performed a systematic review of 37 articles in the medical literature related to microneedling. They found that the procedure provides good results when used on its own, and is preferred by patients because of its minimal downtime and side effects. However, they concluded that, while microneedling is a safe and effective option, methodological shortcomings and further research is required to establish it as an evidence-based therapeutic option.
“There are a limited number of high-quality studies demonstrating the efficacy of microneedling,” Dr. DiGiorgio said. “It is a safe procedure, which could complement laser treatments, so you could perform it between expensive and high-downtime lasers. It is an option for patients who seek measurable results with little to no downtime, and it’s also an option for clinicians who do not use laser-resurfacing devices. Basically, further research is needed to establish microneedling as an evidence-based therapeutic option. Laser continues to remain the gold standard for treatment.”
Another treatment option is fractional microneedling with radiofrequency (RF). These are microneedles which deliver energy in the form of RF at the tip of the needle, which denatures collagen and creates thermal coagulative injury zones at temperatures greater than 65° C. The microneedles can be insulated or noninsulated. “Insulated tips are safer for darker skin types because the epidermis is protected from the heat damage,” Dr. DiGiorgio said.
These treatments are used for the improvement of rhytides and scars and for skin tightening. “The treatments are painful and require topical anesthesia,” she said. “Erythema can range from about 24 hours to 4 days depending on the device being used. Usually monthly treatments are recommended.”
A study by investigators in South Korea and China set out to analyze histometric changes of this approach in pigs. They treated the pigs with a fractional microneedle delivery system at various depths, conduction times, and energies, and performed punch biopsies immediately after treatment, 4 days post treatment, and at 2 weeks post treatment. They noted that depth and conduction time affected the height, width, and volume of the columns of coagulation, but that the energy only affected the level of tissue destruction. “They also noted that RF-induced coagulated columns had a mixed cellular infiltrate, neovascularization, granular tissue formation with fibroblasts, and neocollagenesis and elastogenesis in the dermis,” Dr. DiGiorgio said.
In another study, researchers in Thailand performed a study in two women who were going to undergo abdominoplasty. Participants received six treatments prior to abdominoplasty with biopsies at different time intervals following microneedling with radiofrequency. The researchers tested five energy levels and five test areas; no collagen denaturization was observed with microneedling alone.
“This supports the idea that heat is required to stimulate neocollagenesis, and needles alone do not denature collagen,” Dr. DiGiorgio said. “They also found that neocollagenesis and neoelastogenesis occurred at optimal heating levels.”
In a separate study, researchers from Denmark used a number of different imaging modalities to evaluate the impact of microneedle fractional RF-induced micropores. When they used reflectance confocal microscopy, they observed that the micropores showed a concentric shape. “They contained hyper-reflective granules, and the coagulated tissue was seen from the epidermis to the dermal-epidermal junction,” Dr. DiGiorgio said. “This was not seen in the low energy microneedle RF. On optical coherence tomography, they noted that high-energy needle RF showed deeper, more easily identifiable micropores versus low-energy microneedle RF.” On histology the researchers noted that tissue coagulation reached a depth of 1,500 mcm with high-energy microneedle RF, but low-energy microneedle RF only showed visible damage to the epidermis. “This also supports the idea that microneedles alone without energy do not reach the deeper layers of the dermis,” she said.
Dr. DiGiorgio concluded her presentation by discussing promising results from a split-face study of fractional microneedling RF for the treatment of rosacea. For the 12-week randomized study, researchers from South Korea performed two sessions 4 weeks apart, with no treatment to the control side. Erythema decreased 13.6% and results were maintained for about 2 months after treatment. The researchers also measured inflammatory markers and noticed decreased dermal inflammation and mast cell counts and decreased markers related to angiogenesis, inflammation, innate immunity, and neuronal cation channels. “This could be a promising treatment for inflammatory rosacea in the future,” Dr. DiGiorgio said.
She disclosed that she is a consultant for Allergan Aesthetics.