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Free flap transplantations and replantations of extremities are threatened by venous occlusion due to haematomas, contusions, and secondary healing of the surrounding tissues. In an experimental investigation in 18 Sprague-Dawley-rats, the influence of the Prostacyclin analogue Iloprost on temporary ischemia by venous occlusion was tested. Free groin flaps were transplanted to the neck of these animals with microanastomoses of the nutrient superficial epigastric vessels to the carotid artery and the jugular vein. On the first postoperative day the vein was temporarily clamped. In the control group there was always a total loss of the flap by haemorrhagic necrosis. The intraarterial flap perfusion by Iloprost was able to diminish the effects of the secondary ischemia. In some cases shortly after the perfusion and always on the next day, positive oxygen pressures were measurable. 80% of the flaps survived.

Free flap transplantations and replantations of extremities are threatened by venous occlusion in the postoperative course. In rats, free autogenous groin flaps were transplanted to the neck using microsurgical techniques. On the first postoperative day, the draining vein of the flap was temporarily clamped. In the control group there was always a total loss of the flaps by haemorrhagic necrosis. The intraarterial flap perfusion by iloprost during the clamping was able to diminish the ischaemic effects; 80% of the flaps survived. The systemic application of iloprost by intravenous infusion reduced the ischaemic effects in a similar way. Serious complications such as intraabdominal bleeding or bleeding in the donor area were seen after intravenous administration. Cicaprost had a similar protective effect on flap ischaemia after intravenous infusion. Flap survival was comparable to iloprost. Severe complications seemed to be less. Prostacyclin analogues were able to diminish damage of secondary ischaemia caused by venous occlusion.

Background: Free jejunal flaps are among the most commonly used flaps for esophageal reconstruction. However, ischemia-reperfusion injury caused by warm ischemia seen during transfer limits their use. Iloprost, a prostacyclin analogue, has been shown to reduce ischemia-reperfusion injury in various organs. The authors investigated tissue damage in jejunal flaps with iloprost and ischemic preconditioning and compared the effectiveness of these two modalities., Methods: Thirty-four Sprague-Dawley rats were randomized into five groups: sham, ischemia-reperfusion (control), ischemic preconditioning, iloprost, and ischemic preconditioning plus iloprost. All flaps, except those in the sham group, underwent ischemia for 60 minutes and reperfusion for 2 hours. Flap perfusion was assessed by laser Doppler perfusion monitoring. Histologic sections were scored using the Chiu scoring system. Superoxide dismutase and myeloperoxidase levels were measured spectrophotometrically., Results: Animals that were administered iloprost and/or underwent ischemic preconditioning had better postischemic recovery of mesenteric perfusion (ischemic preconditioning, 78 percent; iloprost, 83 percent; ischemic preconditioning plus iloprost, 90 percent; versus ischemia-reperfusion, 50 percent; p < 0.05). All intervention groups showed improved histology of jejunal flaps following ischemia-reperfusion injury (ischemic preconditioning, 3; iloprost, 2.3; ischemic preconditioning plus iloprost, 3.2; versus ischemia-reperfusion, 4.7; p < 0.01, p < 0.001, and p < 0.05, respectively). Superoxide dismutase levels were higher in ischemic preconditioning, iloprost plus ischemic preconditioning, and iloprost groups (ischemic preconditioning, 2.7 ± 0.2; ischemic preconditioning plus iloprost, 2.5 ± 0.3; versus ischemia-reperfusion, 1.2 ± 0.1; p < 0.01; iloprost, 2.4 ± 1.1; versus ischemia-reperfusion, 1.2 ± 0.1; p < 0.05). Myeloperoxidase, a marker for neutrophil infiltration, was lower in the iloprost group (iloprost, 222 ± 5; versus ischemia-reperfusion, 291 ± 25; p < 0.05)., Conclusions: This study showed that both iloprost and ischemic preconditioning reduced reperfusion injury in jejunal flaps. Based on histologic results, iloprost may be a novel treatment alternative to ischemic preconditioning.

Summary Background Stress conditioning is thought to improve microvascular free flap survival but the mechanisms of protection are not clear. The aim of this study was to determine whether local induction of heat-shock protein (HSP) 32 improves microvascular perfusion in transferred osteomyocutaneous flaps. Methods The hindlimb harvest region of osteomyocutaneous flaps in Wistar rats was subjected to stress conditioning by local heating (30 min, 42·5°C) 24 h before microvascular flap transfer. In a second group of animals, after heat-shock priming, the action of HSP-32 was inhibited by tin protoporphyrin IX. Animals with unconditioned flaps served as controls. After transfer, the microcirculation of the muscle, cutaneous, subcutaneous and periosteal tissue of the flap was analysed quantitatively for 6 h using intravital fluorescence microscopy. Results Immunohistochemistry revealed that HSP-32 was detectable only after priming and not in unconditioned flaps. Priming did not alter functional capillary density or capillary red blood cell velocity compared with that in unconditioned flaps. However, heat-shock priming induced significant capillary dilatation (P < 0·05) and thus a substantial increase in capillary blood flow volume (P < 0·05) in all tissues of the transferred flaps. Inhibition of HSP-32 by tin protoporphyrin IX completely abolished the priming-induced improvement in capillary perfusion, as indicated by the lack of increased capillary diameters and volumetric blood flow. Conclusion The present study demonstrated that stress conditioning by local heat-shock priming improves nutritive perfusion in osteomyocutaneous flaps by capillary dilatation, probably mediated through the vasoactive action of HSP-32. [ABSTRACT FROM AUTHOR]

The effects of an intravenous infusion of L-arginine as a physiological precursor of endothelium-derived relaxing factor/nitric oxide (EDRF/NO), iloprost (a stable prostacyclin (PGI) analogue), and L-arginine combined with iloprost on skin viability were studied in 9 × 3 cm random pattern skin flaps in rats. Intravenous infusion of all drugs was started at the beginning of the operation and continued for 60 minutes. At the end of infusion period the depth of fluorescein dye penetration in the skin flap was assessed visually from photographic records, and the flap survival area was measured by the grid method at the seventh postoperative day. There was a significant reduction in distal necrosis of random skin flaps after intravenous infusion of L-arginine, iloprost, and L-arginine combined with iloprost (p < 0.01). Possible mechanisms that may be responsible for impairment of endothelium-dependent vasodilation and vasospasm in the microvasculature of random skin flap and their prevention with L-arginine and iloprost include restoration of the depleted stores of NO which in turn causes vasodilatation and has an antithrombotic effect. [ABSTRACT FROM AUTHOR]

The use of free flaps in head and neck reconstruction raises the question of how to adequately fix a tracheostomy tube without causing local pressure to the vascular anastomosis. We describe a previously unreported technique of securing a tracheostomy tube in the immediate and early post-operative period without vascular compromise of the free flap, using the 'epaulette' technique. We undertook a PubMed literature search for articles describing similar methods of securing a tracheostomy tube in patients with head and neck free flaps, but found none. In our experience of using this method, we encountered no compromised flaps or unplanned extubations. We believe the epaulette technique to be an easy and safe method of securing a tracheostomy tube whilst simultaneously avoiding any local pressure effect on the free flap vessels and anastomosis. [ABSTRACT FROM AUTHOR]