Three dimensional accuracy of mandibular reconstruction by pre-bent reconstruction plate using intra oral versus extra oral approaches following mandibular resection in patients with extensive ameloblastoma 

Abstract

Purpose: This prospective study aimed to compare the intraoral placement of the pre-bent reconstruction plate with that inserted via the extraoral approach, to evaluate their impact on the three-dimensional (3D) position of the proximal segment, after continuity resection of mandibular ameloblastoma.Patients and methods: Patients were divided into two equal groups. In group 1, the mandible was reconstructed with a pre-bent reconstruction plate via an intraoral approach. In group 2, an extraoral approach was used. The primary outcome variables were the need for intraoperative plate readjustment, the time needed for plate insertion, total operation time, difficulties encountered during surgery, and the postoperative stability of the proximal segment. Distances between corresponding anatomical landmarks on the mandibular angle and condyle (A-A`, B-B`, C-C`, B-C`) as well as the intercondylar angle (ICA) and B`XC angle, were measured. The difference between the pre-and postoperative measurements was used to evaluate the reconstruction accuracy. The results of the two groups were compared and analyzed by t-test.Results: Thirty patients were enrolled in this study. In group 1, four plates required minor readjustment. In group 2, only two cases required re-adaptation. The mean time for plate placement was 38 ± 5.8 and 27.5 ± 7.5 minutes in groups 1 and 2, respectively (p = 0.0001). The intraoral insertion of the pre-bent plates revealed a decrease in the linear measurements, resulting in mandibular compression. On contrary, the extraoral approach showed increase in the measurements, resulting in widening of the mandible. However, this width difference was statistically insignificant. Concerning the ICA and B`XC angle, no significant difference could be ascertained between the two groups. Conclusion:Intraoral approach is more conservative procedure, thereby achieving the best esthetic outcomes and resulting in a more accurate 3D mandibular reconstruction. This approach is considered the treatment of choice for resection and reconstruction of mandibular ameloblastoma. However, if the reconstruction plate cannot be inserted intraorally, then extraoral approach is advised.