Evaluation of the vessels of the lower leg before microsurgical fibular transfer. Part II: magnetic resonance angiography for standard preoperative assessment.

The peroneal artery is the dominant supply of the osteomyocutaneous fibular flap. It has been shown that there can be anatomical variants that could jeopardise the blood supply to the lower limb during harvest of the flap. To avoid postoperative ischaemia of the lower leg, preoperative evaluation of adequate collateral perfusion is essential. We investigated whether magnetic resonance angiography (MRA) accurately shows anatomical variants and pathological stenoses of the vessels of the lower leg and whether it can replace conventional invasive techniques. Conventional digital subtraction angiography (DSA) was used in a prospective study of 15 patients, and contrast-enhanced MRA postoperatively. Arteries were evaluated by three radiologists for: size of vessel at the trifurcation; hypoplastic or missing vessels; appreciable stenosis or vascular occlusion, or both; atherosclerotic malformations; and overall vascular topography. High resolution MRA enabled a reliable judgement to be made of the vessels of the lower leg. MRA definitively detected hypoplastic vessels, stenoses, occlusion, or atherosclerotic changes of the vessels, and enabled both accurate assessment of the quality of vessels and the preferred site for the harvest of the flap. As it is a low risk procedure, it can be done in the outpatient department with no risk of radiation. It can easily replace conventional DSA.