MR angiography versus color-doppler ultrasound for the preoperative assessment of lower extremities prior to fibula flap transfer: results of a prospective clinical study.

Background: Fibula free flap is by far considered the “workhorse” in head and neck surgery to reconstruct osteo-cutaneous defects. Sacrifice of peroneal vessels during fibula harvest can cause ischemia to the leg and foot, when peripheral arterial occlusive disease or vascular anomalies exist.
Methods : 60 patients candidates to jawbones reconstruction by fibula free flap were enrolled in this prospective study. Preoperative evaluation of lower extremities prior to fibula flap transfer was performed by color doppler flow and magnetic resonance angiography in order to compare the accuracy of these procedure.
All legs were evaluated for peripheral arterial occlusive disease (PAOD) and anatomical variations that could contraindicate fibula flap harvest.
Donor legs were considered normal at CDF imaging in the presence of triphasic or biphasic flow with a perfect spectral window. Biphasic flow with spectral broadening and/or a “bad” reverse wave and monophasic with or without continuous flow component at popliteal, ATA, PTA and peroneal arteries were considered representative of moderate to severe PAOD.
MRA imaging of the popliteal branching pattern was examined referring to the classification system proposed by Kim et al. Arterial anatomy of the calves was considered normal at MRA if no luminal reduction and a type I pattern was observed. The severity of PAOD at MRA was graded using a 3-point scale: 0, normal; 1, mild stenosis (up to 50% luminal compromise); 2, significant stenosis up to occlusion.
PAOD was considered an absolute contraindication to fibula flap harvest if graded 2 at MRA or when monophasic flow was detected at CDF. Type IIIC pattern was also considered an absolute contraindication. Different types of vascular anomalies were graded and evaluated for any decision making change regarding site of flap harvesting.