Читать книгу Microneedling - Группа авторов - Страница 15

Rollers have many fine‐gauged needles that are on a cylindrical surface that pierces the skin on an angle. The rollers are fixed; the parameters are uniform for each device that you use. Unlike pens, you can not mechanically adjust rollers. The quality of rollers is also critical. Patients are seeking at‐home rollers but the quality of the needles is paramount. Needles that are dull or loose may cause tears in the skin and foreign body reactions, including but not limited to granulomas.

The most important factor is needle length. A high ratio of tip length to diameter (13:1) is an important property of good needles [9]. The length of needle selected for an individual patient depends upon the indication for microneedling. For treating acne and other scars as a routine, a needle length of 1.5–2 mm is usually used. When microneedling is used as a procedure to treat aging skin and wrinkles, a needle length of 0.5 mm or 1.0 mm is usually recommended [19]. The needle length to use will also depend on the thickness of the epidermis and dermis of the skin for optimal results.

Given their design and mechanics, rollers are able to pierce the skin deeper when at a 90‐degree angle or perpendicular to the skin. Fernandes showed that with the use of rollers you have an intact epidermis with microchannels spaced out with about a four‐cell width distribution [4]. The provider’s technique with these devices is critical. Tearing of the epidermis may occur if performed incorrectly, with too much pressure, or at an increased speed. The needle rollers themselves are variable based on the materials used, needle length and diameter, and total number of needles. The quality of the rollers is also critical to evaluate.

Needle length is generally 0.2–3.00 mm, with a diameter of > 0.25mm and the materials are variable: stainless steel, titanium, or silver and gold. Stainless steel is the most common type of needle, silver and gold offer antimicrobial properties and carry less of a risk of allergic reactions, and titanium needles usually stay sharper longer (see Figure 1.5).

Figure 1.5 Current rollers with fixed needle length; some current models are autoclavable.

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