Clinical and morphological characteristics of the vascular bed of hypertrophic scar tissue in different periods of its formation

Background. The state of the microcirculatory bed in the scar tissue is extremely important for determining the most appropriate methods of conservative and surgical treatments. Only few studies have assessed the vascular features of scar tissue.

The objective was to study and analyze the morphological features of the vascular bed of scar tissue and their clinical implications.

Materials and methods. Fifty-four patients with hypertrophic post-burn scars were examined. The study used a clinical method and performed histological analysis of the scars biopsy specimens, including a survey light microscopy, a morphometric assessment of the vascular bed as well as the verification of the collagen fibers of scar tissue with an immunohistochemical (IHC) analysis with specific monoclonal antibodies (AT) (Novocastra, Bond) to Type I and III collagens.

Results. A significant increase in the total area of the vessels of the rumen in the first 6 months of its formation was observed in comparison with intact skin and later maturation of the scar tissue (in % in 1 mm2 of intact skin – 8.50, in the rumen in terms of up to 6 months – 13.10). The average number of vessels in the scar tissue and the total area of their lumen in the maturing rumen from 2 to 5 years decreased in comparison with that in the intact skin. The nodes were detected in the scars by an early appearance of the clinical signs of vascular disorders including blisters and erosions on thickened and hyperemic scar tissues.

Discussion. In the developing hypertrophic rumen, the circulatory conditions gradually deteriorated due to the compression and obliteration of the vessels of the skin with collagen. The enhancement in perfusion recorded using laser Doppler fluorometry may be associated with a significant dilatation of the rumen vessels, rather than because of actual enhanced perfusion.

Conclusions. 1. The increase in the vascular cross sectional area in the early stages of scar formation is attributable to the expansion of their lumen vessels. In the ripened rumen, the number of vessels is 3 times less than that in intact skin. 2. Hyperemia of the hypertrophic scar is caused by a substantial widening of the vessels of the scar tissue, and not by an increase in their number. 3. The use of a hypertrophic scar for the creation of rotational and other flaps is associated with a high risk of trophic complications.