Use of mechanical preconditioning for free flaps in a swine model

Background Mechanical ischemic preconditioning (MIPC) is defined as applying brief periods of ischemia before tissue reperfusion. This mechanism protects tissues against injury from sustained ischemia followed by reperfusion. We aimed to analyze the effects of MIPC on the tolerance of muscle flap tissue depending on the type and duration of ex vivo cold ischemia storage. Methods We studied the effects of MIPC on interstitial edema, inflammation, and muscle necrosis. Thirty-two porcine latissimus dorsi flaps were equally divided over four groups. Groups were divided based on the application of MIPC (every 15 min for a total of 1 h) or not, and the submersion into heparin or IGL-1®. Iterative biopsies were performed before harvesting the flap and one, two and 3 h after cold ischemia storage. Results Preconditioning free flaps before cold storage in heparin significantly decreased muscle necrosis, interstitial edema, and muscle cell size. Respectively, a decrease of 67%, 37% and 28% was seen in this group ( p < 0.05). Preconditioning free flaps before cold storage in IGL-1® reduced necrosis by 26%, interstitial edema by 37% and muscle cell size by 33% ( p < 0.05). Conclusions We found that MIPC significantly reduces interstitial edema, inflammation and necrosis and may increase the rate of successful revascularizations. However, studies assessing those tissular damage parameters after reperfusion of the flap need to be performed to assess more correctly inflammation and post-operative infections and to confirm the potential benefits of ICP. Level of evidence : Not gradable