Using the skin replacement materials Corethium 2, Coldex,
Epigard and
SYSpur-derm, both fresh
wound and
wounds up to 6 days old were covered in rats. The histological work-up 1-7 days later showed material-dependent differences in the
wound reaction. Under Corethium 2, a heavy layer of
wound exudate formed on the first day both on fresh and granulating
wound surfaces. Beneath this layer granulation tissue formed that was of regular thickness and well vascularized, filling the defect. Reepithelialization of the
wound surface was not hindered by the material. In contrast, a strong connection was established between the
wound base and the covering material when using the three foam substances Coldex,
Epigard and
SYSpur-derm, through the formation of granulation tissue. This process was dependent on the age of the
wound. Thickening of the granulation tissue under the covering material was suppressed by the foam substances. Reepithelialization of the surface of the
wound was disturbed by the growth of granulation tissue. The netlike structure of
Epigard and the properties of the cover layer (fluid-resistant and protective against bacteria) make it possible for the granulation tissue to infiltrate evenly in the whole area of the
wound covering and permit growth within the material right up to the surface. In addition to granulation tissue, epithelium also grows into the foam and spreads evenly.
Epigard is suitable for long-term covering of large
wounds.
SYSpur-derm has a different fine structure than
Epigard, which hinders the growth of granulation tissue, so that there are only cone-shaped connections between the
wound base and the covering material. Rapid desiccation of the
wound exudate cannot be prevented. Leukocytes and granulation tissue cannot spread in the foam. With
SYSpur-derm an intermediate layer of
wound exudate was observed more frequently than with
Epigard.
SYSpur-derm should be changed regularly in order to remove the detritus and exsudate from the
wound. In comparison with
polyurethane foam material the
polyvinyl-alcohol foam (Coldex) was more complicated to handle, did not adapt as well to the
wound, and dried up within a few hours. Between the base of the
wound and Coldex, an intermediate layer often formed and, because of the rapid drying-out process, there was appreciably less infiltration with leukocytes and granulation tissue than with
SYSpur-derm. With Coldex, as a rule the granulation tissue was more generously vascularized than in the other three materials.