Free flap salvage via direct urokinase injection into thrombosed veins: a case report.

Intraoperative use of urokinase is a recognized method for salvaging compromised free flaps. However, protocols for dosage and administration vary, and no consensus exists regarding the optimal technique. Herein, we report a case of postoperative venous thrombosis in a free fibular flap. Despite the unsuccessful intra-arterial administration of urokinase owing to an extensive venous thrombus, we attempted to dissolve the thrombus through direct intravenous infusion using a 27 G needle at multiple sites in the vein where the thrombus had formed. Ten minutes after direct injection into the venous thrombus, venous blood flowed out and successful thrombolysis was achieved. Re-anastomosis was performed, leading to full use of the skin flap without partial necrosis. No hemorrhagic complications were observed. Intra-arterial injection of urokinase is an effective method of thrombolytic therapy for flap salvage. However, when the vein is completely occluded by thrombus, intraflap circulation of the agent via arterial infusion becomes difficult. Direct injection of urokinase into the occluded vein may serve as a potential method for resolving venous obstruction within the limited ischemic time of the flap.