Cross over to better results

February 1, 2007

It is the TCA application, and not self-healing processes, that activates the dermal fibroblasts and results in significant morphologic changes.

Seoul, Korea - A recent breakthrough study has proven that the application of trichloroacetic acid (TCA) using the chemical reconstruction of skin scars (CROSS) method is far more effective than the simple application of TCA.

This method shows great promise for the future of atrophic scar treatment. Whether atrophic scarring of the skin is the sequelae of severe acne, chicken pox or other similar skin trauma, most dermatologists would agree that these lesions can be difficult to treat and there are very few effective cosmetic solutions. The local application of TCA is one such treatment used to correct atrophic skin scarring. The CROSS method bumps it up a notch.

Kee-Yang Chung M.D., of the department of dermatology and cutaneous biology Research Institute at Yonsei University College of Medicine, here, and his colleagues conducted an in vitro study on five hairless mice, evaluating the effects of TCA on iatrogenically induced atrophic skin patches while comparing the traditional delivery method of TCA to the CROSS method.

Comparing to CROSS

In the study, TCA was applied in various concentrations (30 percent, 50 percent, 65 percent and 100 percent) to diverse atrophic areas, using both the simple technique of TCA application (using a cotton-tipped swab) and the CROSS method of application (using a sharpened wooden applicator).

The study results showed similar histologic changes in the two methods, in respect to epidermal and dermal rejuvenation, as well as masses of new collagen deposition. Dr. Chung says, however, that the changes were more prominent in the areas treated via the CROSS method, especially when 100 percent TCA was used.

"The CROSS method using 65 percent TCA on normal skin, but not on scar, showed more prominent increase in epidermal thickness than simple application with 65 percent TCA on normal skin. The CROSS method using 100 percent TCA, however, on both normal skin and scar, was more effective than simple application with 100 percent TCA on normal skin," Dr. Chung says.

Dr. Chung noticed that the dermal tissue showed a marked thickening when treated with 65 percent and 100 percent TCA using the CROSS method. Statistically significant dermal thickening was seen in all tissues (normal and scar tissues) at these concentrations, but results were most prominent when the CROSS method was employed, particularly at 100 percent TCA concentration.

According to Dr. Chung, the main component of the thickened dermis was increased collagen, as the Maason's Trichrome stain (Artisan) proved. Also, Dr. Chung noticed elongated and more spindle shaped fibroblasts in the dermis, regardless of TCA application technique, when compared to untreated or normal skin. He says that this shows that it is the TCA application, and not self-healing processes, that activates the dermal fibroblasts and results in significant morphologic changes.

Specifics of CROSS application

"In the CROSS method, frosting is achieved by pressing firmly in a close meshwork-like fashion to cover the entire depressed area of atrophic scars, but the quality of frosting is not different from that of the traditional TCA application," Dr. Chung explains.

When treating small atrophic skin defects in his Asian patients, Dr. Chung uses multiple, deep and firm applications using CROSS method with 100 percent TCA until even frosting is formed. He says that the rate of complications concerning dyspigmentation and scarring is negligible even in Asian skin. Most notable sequela is prolonged erythema but this fades away in a few months.

"Despite the greater effort and time needed compared to the conventional chemical resurfacing method, the CROSS technique is being widely used due to the superior clinical results, rapid healing time and lower complication rate," Dr. Chung says.

"Our study shows that the improvement of atrophic scars with TCA depends on the application method as well as TCA concentration, and that deeper and focal TCA delivery is more effective than the simple application technique," he says.