Accuracy of computer-assisted mandibular reconstructions with free fibula flap: Results of a single-center series

Objectives: We evaluated the accuracy of computer-assisted mandibular reconstructions.

Patients and methods: We retrospectively reviewed data for 26 patients who had mandibular reconstruction with a microvascular free fibula flap, January 2015 to June 2018. Postoperative mandible models were obtained from computed tomography scans. After registering the models to the corresponding preoperative plan, we performed comparative measurements. Patients were grouped by condylar involvement and subdivided based on number of fibular segments used for reconstruction. For each segment, we measured length and osteotomy angles. For the final postoperative outcome, we compared intercoronoid, intergonial, and anteroposterior distances and intersegmental plane shift.

Results: Means (SD) for deviation of each osteotomy angle and fibular segment length were 1.98° (2.98) and 1.78 mm (2.69), respectively, remaining constant across subgroups. Other mean values were as follows: intercoronoid distance deviation, 3.86 mm (range, 0.20-11.21 mm); intergonial distance deviation, 3.14 mm (range, 0.05-8.28 mm); anteroposterior distance deviation, 2.92 mm (range, 0.03-8.49 mm); and intersegmental plane shift, 11.00° (range, 2.76-24.15°). Where the condyle was preserved, the intercoronoid and intergonial deviation means differed significantly (respectively 5.02 mm and 4.88 mm, both P < 0.05) for one-segmented and three-segmented fibular reconstructions. Furthermore, reconstructions involving the condylar region compared with condyle preservation showed significantly different intersegmental plane shifts (7.18°; P < 0.05).

Conclusion: Computer-assisted surgery provides cutting guides for obtaining accurate fibular segments, but current fixation methods lead to inaccuracies and reproducibility errors. In multisegmental transfer with condylar involvement, computer-assisted fixation is recommended to ensure accuracy of the preoperative plan.