The effect of solvent extraction and sterilization procedure on the tissue response to Dacron velour

The effects of solvent extraction and sterilization procedure on tissue response to Dacron velour were studied in a canine model, using histomorphometrical techniques. The solvents used for extraction of low molecular weight moieties were either ethanol or water: the sterilization techniques examined were ethylene oxide (ETO) treatment, steam sterilization, and radiofrequency glow discharge (RFGD) treatment. The effect of the sterilization procedure was most marked in the outermost regions (velour) of the implant; no sterilization effects were determined in the capsule or the knitted regions. Velour in the steam sterilized implants had the smallest blood vessel dimensions compared with those that were treated with ETO or RFGD. The effects of different extraction methodologies appeared to be more significant than sterilization effects and were detected further into the implant. That is, not only were extraction effects detected in the capsule and velour, they were also detected in the outer knitted region. Extraction with water resulted in histological responses considered more biologically desirable (thinner capsule, lower giant cell presence, and larger blood vessel diameters) than responses to extraction with ethanol. Neither extraction nor sterilization effects were detected in the inner layers of the knitted region, which were adjacent to the adhesive.