title: Finite element analysis of customized reconstruction plates for mandibular continuity defect therapy.
abstract: Large mandibular continuity defects pose a significant challenge in oral maxillofacial surgery. One solution to this problem is to use computer-guided surgical planning and additive manufacturing technology to produce patient-specific reconstruction plates. However, when designing customized plates, it is important to assess potential biomechanical responses that may vary substantially depending on the size and geometry of the defect. The aim of this study was to assess the design of two customized plates using finite element method (FEM). These plates were designed for the reconstruction of the lower left mandibles of two ameloblastoma cases (patient 1/plate 1 and patient 2/plate 2) with large bone resections differing in both geometry and size. Simulations revealed maximum von Mises stresses of 63 MPa and 108 MPa in plates 1 and 2, and 65 MPa and 190 MPa in the fixation screws of patients 1 and 2. The equivalent strain induced in the bone at the screw-bone interface reached maximum values of 2739 micro-strain for patient 1 and 19,575 micro-strain for patient 2. The results demonstrate the influence of design on the stresses induced in the plate and screw bodies. Of particular note, however, are the differences in the induced strains. Unphysiologically high strains in bone adjacent to screws can cause micro-damage leading to bone resorption. This can adversely affect the anchoring capabilities of the screws. Thus, while custom plates offer optimal anatomical fit, attention should be paid to the expected physiological forces on the plates and the induced stresses and strains in the plate-screw-bone assembly.
authors.affiliation: Department of Electronics and Communications Engineering, Tampere University of Technology, 33520 Tampere, Finland; BioMediTech, Institute of Biosciences and Medical Technology, Tampere, Finland. Electronic address: nathaniel.narragirish@tut.fi.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Narra
authors.affiliation: Institute of Solid Mechanics, Mechatronics and Biomechanics, Faculty of Mechanical Engineering, Brno University of Technology, Brno, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Valášek
authors.affiliation: Department of Electronics and Communications Engineering, Tampere University of Technology, 33520 Tampere, Finland; BioMediTech, Institute of Biosciences and Medical Technology, Tampere, Finland.
authors.forename: Markus
authors.initials: M
authors.lastname: Hannula
authors.affiliation: Institute of Solid Mechanics, Mechatronics and Biomechanics, Faculty of Mechanical Engineering, Brno University of Technology, Brno, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Marcián
authors.affiliation: Institute of Biomedical Technology, University of Tampere, Tampere, Finland; Department of Oral and Maxillofacial Surgery, University of Oulu, Oulu, Finland.
authors.forename: George K
authors.initials: GK
authors.lastname: Sándor
authors.affiliation: Department of Electronics and Communications Engineering, Tampere University of Technology, 33520 Tampere, Finland; BioMediTech, Institute of Biosciences and Medical Technology, Tampere, Finland.
authors.forename: Jari
authors.initials: J
authors.lastname: Hyttinen
authors.affiliation: Institute of Biomedical Technology, University of Tampere, Tampere, Finland; Oral and Maxillofacial Unit, Department of Otorhinolaryngology, Tampere University Hospital, Tampere, Finland.
authors.forename: Jan
authors.initials: J
authors.lastname: Wolff
mesh_terms: D000328:Adult; D001860:Bone Plates; D001863:Bone Screws; D003198:Computer Simulation; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D016268:Internal Fixators; D008297:Male; D008334:Mandible / Q000033:anatomy & histology / Q000601:surgery*; D008875:Middle Aged; D011312:Pressure; D019651:Plastic Surgery Procedures / Q000379:methods*; D012984:Software; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Finite element analysis; Mandible reconstruction; Maxillofacial surgery; Rapid prototyping; Reconstruction plate