Which plate results in better stability after segmental mandibular resection and fibula free flap reconstruction? Biomechanical analysis

Abstract

Objective: This study investigated the biomechanical stability of 2 plate systems-mini-plates and reconstruction plates-in reconstruction with fibular free flaps.

Study design: The reconstruction models were constructed by using 2 types of plates in representative cases with segmental mandibular defect (C, L, LC1, LC2). In each model, a masticatory simulation approximating 3 clenching tasks was conducted, using the muscle forces adjusted to the mandible structure used in this study. In addition, to evaluate the sensitivity of the 2 plate systems for masticatory load changes, a sensitivity analysis was also performed by using finite element analysis.

Results: The risks of plate fracture and screw loosening measured by stress concentrations were higher in the cases using mini-plates compared with those using reconstruction plates. Moreover, the mini-plate was more sensitive to varied loads compared with the reconstruction plate and was observed to have less flexibility to absorb external forces. Mini-plates also caused high strain values, indicating the risk of hypertrophy of bone around the screw holes.

Conclusions: The use of a reconstruction plate should result in more stable surgical outcomes in most cases, but we noted that the risk of atrophy may increase with the use of reconstruction plates because of lack of bone stimulation.