[Postoperative position change of fibular bone after reconstruction of maxillary defect using free fibular flap]

To investigate the position change of the fibular bone after maxillary reconstruction by free fibular flap and to analyze the factors affecting the position change.

Patients who underwent maxillary reconstruction by free fibular flap in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from November 2012 to November 2016 were enrolled in this study. CT scans 1 week and 1 year postoperatively were collected and stored in DICOM format. The ProPlan CMF software was used to reconstruct the CT scans and separate the maxilla and each segment of the fibular flap. The Geomagic Control software was used to measure the long axis direction vector of each fibular segment. And the position change direction was recorded. The patients were divided into groups according to the use of the fibula or titanium plate to reconstruct the zygomaticmaxillary buttress.

A total of 32 patients were enrolled. Among them, 21 were in the titanium plate group and 11 in the fibula bone group. The angle between the long axis of the fibular segment and the X axis in the X-Y plane was 95.65°±53.49° and 95.53°±52.77°, 1 week and 1 year postoperatively, and there was no statistical difference (P>0.05). The angle between the long axis of the fibular segment and the X axis in the X-Z plane was 96.88°±69.76° and 95.33°±67.42°, respectively, with statistical difference (P=0.0497). The angular changes of the long axis of the fibular segment in the titanium plate group and the fibular bone group were 3.23°±3.93° and 1.94°±1.78°, respectively, and the angular changes in the X-Z plane were 6.02°±9.89° and 3.27°±2.31°, respectively. There was no significant difference between the groups (P>0.05). The long axis changes of the fibular segment in the X-Y plane for reconstruction of the anterior alveolar, posterior alveolar, and buttress were 3.13°±3.78°, 2.56°±3.17°, and 5.51°±4.39°, respectively. There was a statistical difference (P = 0.023) between the posterior and buttress. In the X-Z plane, theses were 4.94°±4.75°, 5.26°±10.25°, 6.69°±6.52°, respectively. There was no statistical difference among the three groups (P>0.05). The main positional deviation directions of the titanium plate group and the fibular bone group were interior and superior sides, and there was no statistical difference between the two groups (P>0.05).

One year postoperatively, the position of the free fibular flap was changed compared with 1 week postoperatively. The position of the free fibular flap was mainly changed to the interior and superior sides.