Risk and consequence of infection at the site of microsurgical repair: an experimental model

The consequences of postoperative infection at the site of microsurgical repair were studied. The experiment used 60 Wistar rats which were divided into 3 groups of 20 each. The femoral artery, vein, and nerve were transected unilaterally and repaired using microsurgical techniques. Staphylococcus aureus was then inoculated into the wound of group 1. Beta-hemolytic Streptococcus was inoculated into the wound of group 2. Group 3 rats served as controls. Clinical, anatomical, bacteriological and histopathological examinations were performed on postoperative days 8 and 30. Wounds in which S. aureus was inoculated demonstrated a significant tendency toward vascular thrombosis with extensive tissue destruction. In the majority of these cases, the necrosis caused by the primary infection engendered an associated, opportunistic infection. Streptococcal inoculations in group 2 demonstrated less severe changes than in group 1. These changes were characterized by injury of the vascular structures themselves with a significant tendency for thickening of the arterial wall, perivascular inflammation, and hematoma formation at the site of the repair. This model allows demonstration of the enzymatic and toxic consequences of bacterial infection in a postoperative site characterized by cellular destruction and interstitial edema surrounding foreign bodies represented by sutures.