A fixation guide for the accurate insertion of fibular segments in mandibular reconstruction  Toshiaki Numajiri, Shoko Tsujiko, Daiki Morita, Hiroko Nakamura, Yoshihiro Sowa  JPRAS Open  Volume 12, Pages 1-8 (June 2017) DOI: 10.1016/j.jpra.2017.01.001 Copyright © 2017 The Author(s) Terms and Conditions

Figure 1 Defect areas were set randomly in virtual and model surgeries for mandibular repair; 13 paired models were used. JPRAS Open 2017 12, 1-8DOI: (10.1016/j.jpra.2017.01.001) Copyright © 2017 The Author(s) Terms and Conditions

Figure 2 A: The CAD/CAM-generated cutting guide was designed for accurate osteotomy and to be an external fixator of remaining mandible. B and C: Defects were set and fibular transfer was planned. D: Fibular bone segments were placed virtually into the defect. JPRAS Open 2017 12, 1-8DOI: (10.1016/j.jpra.2017.01.001) Copyright © 2017 The Author(s) Terms and Conditions

Figure 3 A, B: A fixation guide was designed (red). This was designed to fit perfectly to the outer surface of the fibular segments. This guide had the same angles at each junction as those of the CAD simulation. C: The combined fibular segments and fixation guide were merged with the mandibular defects because the fibular segments had already been attached to the fixation guide before fixation to the mandible. As fibular segments were simply placed along the fixation guide, there would be no human bias or error in deciding the direction and plane of the transplants during surgery. D: Before transfer to the mandible, the fixation guide was attached to the fibular bone segments. JPRAS Open 2017 12, 1-8DOI: (10.1016/j.jpra.2017.01.001) Copyright © 2017 The Author(s) Terms and Conditions

Figure 4 A: Thirteen pairs of models of surgery were generated to determine whether the fixation guide would contribute to more accurate reconstruction. In the first group, only a conventional CAD/CAM-generated guide was used. In the other group, a fixation guide was used as well. B: After reconstruction, the distances between reference points such as Cl–Cl and Go–Go were calculated and compared between the two groups. JPRAS Open 2017 12, 1-8DOI: (10.1016/j.jpra.2017.01.001) Copyright © 2017 The Author(s) Terms and Conditions

Figure 5 The fixation guide group of models showed a mean deviation of 2.05 mm versus 2.61 mm in the group without fixation guide. The accuracy results of the fixation guide group were significantly better (*p = 0.03). JPRAS Open 2017 12, 1-8DOI: (10.1016/j.jpra.2017.01.001) Copyright © 2017 The Author(s) Terms and Conditions

Figure 6 A: Regardless of whether we used the fixation guide, the positions of the fibular segments in the virtual plans were the same. However, in actual surgery, small fibular segments that are sandwiched by other transferred bones are easily rotated or deviated with small gaps because information about the direction and plane of the transferred bone segment is not available. B: After using the fixation guide, the bone setting was almost the same as in the virtual plan. C: Without the fixation guide, the middle bone segment was slightly rotated and made a small gap at the junction. JPRAS Open 2017 12, 1-8DOI: (10.1016/j.jpra.2017.01.001) Copyright © 2017 The Author(s) Terms and Conditions