Experimental reclamping of free-flap pedicles: the effect of prolonged stasis on the anastomoses and clamp sites.

ABSTRACT

The effect of static blood in direct contact with areas of microvascular anastomoses and previous clamp application for prolonged periods of time has been investigated. The free groin flap was used as a model in 27 white rabbits. The flap pedicle vessels were reclamped proximal to the anastomoses and areas of previous clamp application for periods of time varying between 30 minutes and 4 hours after 15 minutes of blood flow over these areas. A 100 percent patency rate was achieved despite the long periods of reclamping. Histologically, minor intimal damage was visible in the immediate period following anastomoses and clamping of the vessels. After 2 weeks, despite a thickened myofibroblastic intimal lesion, an intact endothelial layer was observed. No evidence of thrombosis could be demonstrated in either period. We postulate that vessels carefully treated and with technically well-performed anastomoses can be regarded as "normal" vessels after 15 minutes of blood flow over the anastomoses and clamp sites. We suggest that when required, microvascular clamps may then be reapplied without risk for prolonged periods of time despite static blood being in contact with these areas.