Tissue reaction to surgical sutures in infected wounds
A comparison was made between Dexon (braided polyglycolic acid), plain catgut, chromic catgut, multifilament steel, monbfilament nylon, braided silk and Mersilene (braided dacron) in infected wounds. Four groups of 15 dogs were used. Three identical rows of 27 subcutaneous pockets were created in each dog. Knots of 3/0 suture were embedded in the pockets. Each suture pocket in the first row was inoculated with O. 1 milliliter of a standard culture of Staphy- 1 .. 416 ococcus aureus, containing 7 x 0 organisms. The other two rows received similar treatment with ten-fold and hundred -fo Id dilutions respectively. Each row had a control pocket inoculated with culture but no suture material, and a second pocket with only the culture medium. Groups of dogs were sacrificed at 6, 10, 20 and 40 days respectively. The diameter of the lesion around each suture was measured grossly. Microscopic measurements of lesions and celluIa r infiltration were used to rate the tissue reactions subjectively. Pockets containing suture materials had significantly more reaction than control pockets. The three dilutions of culture iii produced significantly different reactions. In the acute stage of infection (6 days), steel and nylon elicited the least reaction and catgut produced the most. Silk, Mersilene and Dexon were intermediate. In more chronic stages (10, 20 and 40 days), relative reactions to Mersilene and silk increased. Although Dexon showed intense tissue reaction at 6 days, it elicited relatively little in chronic implantations. Steel and nylon remained relatively inert at all stages. At 20 and 40 days silk evoked the most intense reaction. Microscopic measurements of lesions correlated well with gros s measurements. Neutrophils were the predominant cells in the acute stage. Later, macrophages and fibroblasts predominated. Silk, Mersilene and the catguts .attracted large numbers of neutrophils in chronic implantations, suggesting pe rsistence of infection. The Splendor-Hoeppli phenomenon was demonstrated around silk sutures at 40 days. Suture materials play an important role in postoperative wound infections, and different suture materials elicit different degrees of reaction in contaminated wounds. In chronic implantations, the reaction to various suture materials differs from that observed in the acute stages of infection.