Role of Preoperative Contrast-Enhanced Magnetic Resonance (ce-MRA) Assessment of the Free Fibular Flap in Donor Legs

The purpose of this study was to assess the utility of MRA in the preoperative evaluation of candidates for vascularized fibular free flap reconstruction in the treatment of jawbone defects.

From April 2002 to March 2005, the authors prospectively performed ce-MRA studies from the aortic bifurcation down to the ankle in 22 patients (44 fibulas) who were considered for fibula free flap harvest, in order to assess vessel anatomy and patency. All the examinations were performed with a 1.5T magnet, using a three–station phased–arrays coil. All patients also underwent color-Doppler evaluation. Data obtained from the two techniques were compared for statistical significance.

Contrast–enhanced MRA was useful for assessing the morpho–functional integrity of the vessels of the calf and for the choice of the donor site in all patients. Furthermore, MRA revealed 9 (41%) vascular anomalies (1 bilateral peronea magna, 3 posterior tibial artery with anomalous origin, 1 bilateral peroneal artery hypoplasia, and 4 distal shunts between posterior tibial and peroneal artery), which were not detected by color Doppler. In these patients, flap design was altered. The fibula was excluded as a donor site in 2 patients (9%) (bilateral peronea magna, 1 pt; bilateral peroneal artery hypoplasia, 1 pt). All other patients underwent successful free flap reconstruction with no ischemic complications.

ce-MRA is a low–invasive, very effective, and non–operator–dependent procedure, which allows for safe donor site selection before free fibula flap transfer. Furthermore, concurrent detection of the entire fibular bone, peroneal vessel length, and their relationships is possible, which yields a better assessment of the effective vascularized bone stock accessible before the harvest.