Impact of segment length on bony changes following microvascular jaw reconstruction using virtually planned fibula flaps - A retrospective study.

Postoperative bone resorption within the first year after a free fibular flap is a common problem and poses major challenges for subsequent therapies. Due to the concerns of increased bone resorption, short segments in particular, i.e. ≤ 20 mm long, are considered unfavorable despite insufficient data in the literature. Therefore, the aim of this retrospective study was to analyze the changes in bone volume (BV), cortical thickness (cTh) and cortical density of especially short fibula segments one year after microvascular jaw reconstruction. Eighty-six fibula segments were included in this study, of which 30 segments were ≤25 mm and 16 segments were ≤20 mm long. The longer fibula segments served as a comparison for bone remodeling. After 15.10 ± 5.60 months, the changes in total bone volume (BV), cTh and cortical density of the fibula segments were determined from analyses of three-dimensional radiological images, and the percentage bone loss rates were assessed in relation to different segment lengths. All fibula segments showed loss of bone volume (BV) regardless of segment length, with no difference in the relative changes in BV as a function of segment length. While the volume changes were smaller in the shorter segments, the longer segments (average length: 26.50 mm) showed a higher bone loss of up to 25%. Although the total BV of the small segments (≤20 mm) did not change at follow-up, the loss of cortical density was substantial. Based on our findings that the largest bony changes were associated with segments of 25 mm in length, the current clinical practice that fibula segments should not be smaller than 20 mm should be critically reconsidered.