The dermal roller is the precursor to Dermapen — a simple mechanical tool with a rolling drum on a handle, festooned with thin surgical steel needles of a specific length and rolled across the skin to create numerous perforations as it is moved. Needle length may vary between rollers but stay generally within the neighborhood of 1.5 mm. Results are noteworthy, to say the least.
The problem is that while the micro-needle concept is simply and elegantly executed with dermal rollers, it is not ideally executed. Compared to Dermapen it is quite painful, and any post-needling erythema and/or edema tend to last about four days, creating unwanted (if somewhat minimal) downtime. The character of the micro-wounds seen with the dermal roller is much more traumatic to the skin; instead of a rapid vertical needle insertion and withdrawal, dermal rollers dig into the skin and create more of a tearing wound, and may be responsible for the longer downtime.
A study presented at an Australian medical conference [Chu 2012] compared Dermapen and dermal roller technology head-to-head for atrophic acne scarring. Subjects (n=60) presented with predominantly rolling acne scars and had each been previously treated at least once with a dermal roller, suggesting familiarity with the procedure. Although the physician and his staff had successfully needled more than 1000 patients with the dermal roller in this manner, Dermapen won hands down. Users found it quite easy to operate, and objective evaluation via digital scan technology with software analysis revealed greater reduction in scar depth with Dermapen. Additionally, patients rated Dermapen to be less painful with shorter downtime and better clinical outcomes.
There is also marked potential for variability between operators using dermal roller technology. The nature of the rolling drum requires some small amount of pressure during rolling to ensure proper microneedle penetration. This pressure can never be the same between individual users—or between individual treatments by the same user, no matter how experienced—so depth of penetration will be inconsistent to some degree. With Dermapen the device does the work; the user exerts force in a lateral motion perpendicular to the skin’s surface, taking the user out of the proverbial picture. This is an issue because the subject of microneedle therapy is a matter of microscopic differences measured in tenths of a millimeter. Theoretically, different penetration depths have different therapeutic effects, so the ability to create consistent perforation patterns may hold the key to therapeutic value and versatility.
From a practice standpoint ensuring sterility is essential, and with Dermapen it is accomplished with the simple swapping of inexpensive disposable tips. A dermal roller must be manually sterilized between users, which is not a complicated or expensive process but is time consuming and relatively less reliable. Also, the relatively small size of the Dermapen tip makes it capable of needling areas such as the upper lip which a dermal roller cannot easily reach.