Using many tiny doses of botulinum toxin injected in a grid pattern just under the surface of the facial skin may improve skin texture and roughness, according to a study in the November issue of Plastic and Reconstructive Surgery.

The “Microbotulinum” technique is a safe and effective method of facial rejuvenation, yielding objective improvements of about 20 percent in skin texture, microroughness and pore size, report researchers led by Alberto Diaspro, MD, MSc, of the Rigeneralab Centre for Regenerative Medicine in Turin, Italy.

In the standard Botulinum toxin technique, a few injections are made to treat common problems such as frown lines, forehead creases and crow’s feet around the eyes.

The new, less-invasive technique uses a series of tiny “blebs” of botulinum toxin A injected just under the skin surface. The injections follow a one-centimeter grid pattern, extending from the forehead to the cheek and down to the jawline. 

“This targets the superficial fibers of the facial muscles and weakens their insertion into the undersurface of the skin, which is responsible for the fine lines and wrinkles on the face and neck,” Dr. Diaspro and colleagues write.

The researchers used a specialized, high-resolution “skin scanner” system to provide objective data on how the Microbotulinum procedure performed in improving the skin appearance. Graded on a 10-point scale (0 being best, 10 being worst), average skin texture improved from 6.0 to 4.0, while scores for skin “micro-roughness” improved from 7.5 to 5.0. There was a similar and significant reduction in enlarged pore size.

The improvements were backed up by subjective ratings: 90 days after micro-dose treatment, 95 percent of patients were satisfied or very satisfied with their results. As in any botulinum toxin procedure, the effects were temporary, lasting up to 120 days. After that, treatment would need to be reported in order to maintain the improvement.

The results of the Microbotulinum technique appeared best in middle-aged patients. Dr. Diaspro and colleagues believe it will be most appropriate for patients ranging from their mid-thirties to early fifties. The researchers emphasize the need for further studies to determine the optimal dose of botulinum toxin to produce a longer-lasting effect at the dilution used.