Biomechanical Analysis of Various Reconstructive Methods for the Mandibular Body and Ramus Defect Using a Free Vascularized Fibula Flap

Abstract

Several different methods exist for reconstructing the mandibular body and ramus defect with the use of a free vascularized fibula flap, but none have adequately addressed the long-term mechanical stability and osseointegration. The aim of this study is to compare the biomechanics of different surgical methods and to investigate the best approach for reconstructing the mandibular body and ramus defect. Five finite element models based on different reconstructive methods were simulated. Stress, strain, and displacement of connective bone sections were calculated for five models and compared. The models were printed using a 3D printer, and stiffness was measured using an electromechanical universal testing machine. The postoperative follow-up cone beam computed tomography (CBCT) was taken at different time points to analyze bone mineral density of connective bone sections. The results showed that the "double up" (DU) model was the most efficient for reconstructing a mandibular body and ramus defect by comparing the mechanical distribution of three sections under vertical and inclined loading conditions of 100 N. The stiffness detection showed that stiffness in the DU and "double down" (DD) models was higher compared with the "single up" (SU), "single down" (SD), and "distraction osteogenesis" (DO) models. We used the DU model for the surgery, and postoperative follow-up CBCT showed that bone mineral density of each fibular connective section increased gradually with time, plateauing at 12 weeks. We conclude that a free vascularized fibula flap of the DU type was the best approach for the reconstruction of the mandibular body and ramus defect. Preoperative finite element analysis and stiffness testing were shown to be very useful for maxillofacial reconstruction.

Changes in condylar position and morphology after mandibular reconstruction by vascularized fibular free flap with condyle preservation

“…Patients' functional outcomes can be affected by various factors. Some scholars proposed that simultaneous implant denture restoration could accelerate the recovery of occlusion [52]. However, only some of the patients with benign lesions could be suitable for this treatment.…”

Computational models and their applications in biomechanical analysis of mandibular reconstruction surgery

“…However, there are a limited number of studies that considered more sophisticated modelling. For instance, Li [58] et al utilized sliding contact to define the interfaces between the condyle process and the disc in TMJ and sliding between the interfaces was allowed during the simulation process, while in a work by Li et al [82], a TMJ disc is defined and connected to the mandible with springs.…”

“…The iliac crest demonstrates stress distributions more similar to that of the native mandible and in some cases, the von Mises stress in fibular reconstructions was higher than those of the iliac crest reconstructions [29]. Furthermore, the 2 studies that applied a double barrel fibula technique stated that this was "the most efficient approach for the reconstruction of the mandibular body and ramus defect [58]" and that modeling a double barrel flap would "simulate a high fidelity reconstructive surgery [41]. "…”

Additively Manufactured Lattice-like Subperiosteal Implants for Rehabilitation of the Severely Atrophic Ridge

“…It is a valid, accurate, and non-invasive method that can simulate complex anatomical structures and calculate the complex biomechanical behavior of each tissue structure, including the internal stress and strain distribution . For dental implants, FEA has been used to evaluate the biomechanical performance of various prostheses and loading conditions, investigate the stress distribution in the supporting bone tissue, and provide case-specific surgical planning and clinical outcome prediction. , …”