New device measures skin tension lines

March 25, 2019

Researchers have developed a device that may eliminate the need for maps, guidelines or manual skin tension estimation techniques.

Researchers have developed a device that in one step can quickly and non-invasively measure skin tension lines, according to an article published online February 5, 2019, in the Elsevier journal Acta Biomaterialia.

Human skin exhibits anisotropy largely due to collagen and elastin fiber alignment in the dermis. The result in skin is greater tension and a stiffer appearance in one direction than another. Plastic surgeons and others use skin tension lines to make incisions where scars might be least conspicuous. Studies suggest skin tension is an important contributing factor for scar formation, the authors report.

The challenge for surgeons is that while skin tension guidelines exist, skin anisotropy is thought to vary from patient to patient. And until now there was no system that could rapidly and non-invasively measure skin tension lines in vivo, according to the authors.

Researchers at Binghamton University, State University of New York, have developed a device that applies a radial stress of 17kPa to a skin region. The device painlessly captures radially asymmetric skin deformations with a dermal camera. In a matter of seconds, the deformations quantify skin strain and the direction in which there is the greatest skin stiffness, according to the paper.

Researchers characterized skin tension line orientations for subjects between ages 18 to 30 years by measuring skin on the back of the left calf and back of the upper right arm. The researchers found individual subjects had statistically significant variations in skin tension line orientation.

The device, they found, accurately and efficiently measures skin tension line direction, eliminating the need for maps, guidelines or manual skin tension estimation techniques, according to study author Guy German, Ph.D., associate professor of biomedical engineering at Binghamton University, State University of New York.

“The device would be used during the surgical planning stage. The device would quickly and accurately quantify the orientation of collagen fibers in the skin at one or more anatomical sites where incisions will be made,” Dr. German says. “With this knowledge, a surgeon could then map out their incision orientations accordingly. We anticipate that our system can provide a more accurate estimate of collagen orientation relative to existing manual manipulation protocols that estimate relaxed skin tension lines by pinching the skin and observing the furrows that form.”

Although the study doesn’t look at resulting scar reduction, Dr. German says there are many studies that demonstrate improved wound healing and lower risk of keloid scarring when clinicians make incisions that are aligned with collagen fiber orientation.

Clinicians in a variety of settings could use the device for such applications as incision planning, measuring cosmeceutical skincare product efficacy and for monitoring skin aging and wounds, the authors write.

There is room for improvement in the device’s ability to capture facial skin tension lines.

“Future work should investigate how the development of a smaller suction ring might enable the straining system to capture changes in skin tension line orientation with improved spatial resolution. This would be especially beneficial in applications involving facial skincare and surgery, since facial skin tension lines exhibit complex patterns with high curvature,” the authors write.