We report a case in which venous occlusion occurred after fibular osteocutaneous flap transfer for open tibial fracture. The flap was salvaged using an external venous shunt. The shunt consisted of a Teflon catheter for intravenous infusion, a three-way stopcock, a urokinase-immobilised catheter and a pressurising bag for arterial-pressure monitoring. This method can be used to establish venous drainage when there is no accessible recipient vein. It may improve the success rate of microvascular surgery and extend the indications for surgery.