Directional variance in skin movement

A Randomized, Controlled Trial to Determine the Efficacy of Paper Tape in Preventing Hypertrophic Scar Formation in Surgical Incisions that Traverse Langer??s Skin Tension Lines

BACKGROUND

How a scar is managed postoperatively influences its cosmetic outcome. After suture removal, scars are susceptible to skin tension, which may be the trigger for hypertrophic scarring. Paper tape to support the scar may reduce multidirectional forces and prevent hypertrophic scarring.

METHODS

Seventy patients who had undergone cesarean section at the Royal Brisbane and Women's Hospital were randomized to treatment and control groups. Patients in the control group received no postoperative intervention. Patients in the treatment group applied paper tape to their scars for 12 weeks. Scars were assessed at 6 weeks, 12 weeks, and 6 months after surgery using ultrasound to measure intradermal scar volume. Scars were also assessed using the International Clinical Recommendations.

RESULTS

Paper tape significantly decreased scar volume by a mean of 0.16 cm3, (95 percent confidence interval, 0.00 to 0.29 cm3). At 12 weeks after surgery, 41 percent of the control group developed hypertrophic scars compared with none in the treatment group (exact test, p = 0.003). In the treatment group, one patient developed a hypertrophic scar and four developed stretched scars only after the tape was removed. The odds of developing a hypertrophic scar were 13.6 times greater in the control than in the treatment group (95 percent confidence interval, 3.6 to 66.9). Of the 70 patients randomized, 39 completed the study. Four patients in the treatment group developed a localized red rash beneath the tape. These reactions were minor and transient and resolved without medical intervention.

CONCLUSIONS

The development of hypertrophic and stretched scars in the treatment group only after the tape was removed suggests that tension acting on a scar is the trigger for hypertrophic scarring. Paper tape is likely to be an effective modality for the prevention of hypertrophic scarring through its ability to eliminate scar tension.

Collagen morphology in human skin and scar tissue: no adaptations in response to mechanical loading at joints

Dermal collagen displays a random-like structure that has a major role in strength and function of the human integument. It is hypothesised that collagen bundles align in a parallel fashion in the direction of mechanical tension during scarring, which may explain the problematic scar formation that occurs specifically at joints. Scar tissue and normal skin were biopsied from joints and control areas and evaluated by the Fourier analysis. Collagen orientation was represented by an index ranging from 0 (perfectly random) to 1 (perfectly parallel). Collagen bundle packing signifies the average distance between the centres of collagen bundles. No differences were shown in collagen morphology of scar tissue and normal skin between joints and control areas. Normal skin had a significantly lower collagen orientation index than scar tissue (0.26 versus 0.44, P<0.001). The bundle packing of scar tissue differed significantly from normal skin (18.1 microm versus 23.7 microm, P<0.001). Collagen appeared less parallel orientated in deep dermis compared to superficial dermis especially for normal skin (0.27 versus 0.33, P=0.06). Normal skin had a less parallel organisation in sections that were cut parallel compared to those that were cut perpendicular to the epidermis (0.24 versus 0.30, P=0.02). Collagen orientation of scar tissue is more parallel compared to normal skin. Morphology differs with respect to superficial and deep dermal layers and parallel and perpendicular planes, but appears not to respond to mechanical tension.