Towards mechanobiologically optimized mandible reconstruction: CAD/CAM miniplates vs. reconstruction plates for fibula free flap fixation: A finite element study

Abstract

Due to their advantages in applicability, patient-specific (CAD/CAM) reconstruction plates are increasingly used in fibula free flap mandible reconstruction. In addition, recently, CAD/CAM miniplates, with further advantages in postoperative management, have been introduced. However, biomechanical conditions induced by CAD/CAM systems remain partially unknown. This study aimed to evaluate the primary fixation stability of CAD/CAM fixators. For a patient-specific scenario, the biomechanical conditions induced in a one segmental fibula free flap stabilized using either a CAD/CAM reconstruction plate or CAD/CAM miniplates were determined using finite element analysis. The main output parameters were the strains between intersegmental bone surfaces and stresses in the fixation systems due to different biting scenarios. CAD/CAM miniplates resulted in higher mechanical strains in the mesial interosseous gap, whereas CAD/CAM reconstruction plate fixation resulted in higher strains in the distal interosseous gap. For all investigated fixation systems, stresses in the fixation systems were below the material yield stress and thus material failure would not be expected. While the use of CAD/CAM miniplates resulted in strain values considered adequate to promote bone healing in the mesial interosseous gap, in the distal interosseous gap CAD/CAM reconstruction plate fixation might result in more beneficial tissue straining. A mechanical failure of the fixation systems would not be expected.

Optimizing efficiency in the creation of patient-specific plates through field-driven generative design in maxillofacial surgery

“…Moreover, implicit modeling will allow to model of patient-specific implants that align with the outcomes of FEA analysis 18 , allowing for the optimization of the topological design based on the shear stress and tension the implant is anticipated to endure. This is in line with the “mechanobiological” concept described by Ruf et al 19 , yet this would require additional studies, since this aspect was not developed in this paper.…”

Pemodelan Tegangan dan Regangan pada Bone Plate dengan Menggunakan Material Stainless Steel 316 L

“…Teknologi CAD/CAM merupakan teknologi inovatif yang dapat digunakan untuk mensimulasi secara virtual yang membantu perencanaan treatment pada pasien sebelum dilakukan operasi (Kim et al, 2023) (Chen et al, 2022). CAD/CAM juga mampu merekonstruksi plat sehingga dapat menunjukkan kekakuan yang baik dan mempengaruhi penyembuhan tulang (Ruf et al, 2022). CAD/CAM mampu menggambarkan geometri 3 dimensi pada tulang panjang, bone plate dan screw untuk melihat model tulang dan penyangga yang sulit.…”

A tissue engineered 3D printed calcium alkali phosphate bioceramic bone graft enables vascularization and regeneration of critical-size discontinuity bony defects in vivo

“…Utilizing 3D printed Si-CAOP scaffolds in combination with perfusion flow culture of mesenchymal stem cells, we previously were able to create a 3D printed tissue engineered synthetic bone graft in vitro, with homogenously distributed osteoblasts and mineralizing bone matrix (Adel-Khattab et al, 2018), which mimics the favorable features of autologous bone grafts thereby making it an excellent candidate for subsequent in vivo implantation for repair of extensive segmental discontinuity bony defects such as after subtotal mandibulectomy (Warnke et al, 2004;Lonie et al, 2016;Ruf et al, 2022).…”

“…Reconstruction of extensive and complex bone segments resulting from tumor surgery involving subtotal mandibulectomy (Figure 1) constitutes a challenging problem in craniomaxillofacial surgery (Warnke et al, 2004;Cancedda et al, 2007;Eweida et al, 2012), and often necessitates reconstructing defects, which extend over a length of more than 10 cm from ascending ramus to ascending ramus of the mandible (Warnke et al, 2004;Lonie et al, 2016;Kreutzer et al, 2022;Ruf et al, 2022) (Figure 1). In this context, clinical principles demand, that, when reconstructing segmental mandibular defects 5 cm in width or larger, a vascularized bone graft needs to be used, which contains osteogenic cells and is transplanted with the respective blood vessel, which is then anastomosed with a blood vessel of the recipient site using microvascular surgery.…”

“…The same is true for timely ingrowth of blood vessels from the defect margins. As a result, the clinical standard of care for bone reconstruction after subtotal mandibulectomy involves the use of vascularized fibular (Figure 1) or iliac crest grafts, which contain both osteogenic cells and a blood vessel (Eweida et al, 2014;Lonie et al, 2016;Kreutzer et al, 2022;Ruf et al, 2022;Warnke et al, 2004.). However, in addition to the significant risk of donor-site morbidity, the use of vascularized fibular grafts does often not permit an exact reconstruction of the patient's original anatomic facial and mandibular features, thereby leading to a compromised esthetic and functional result, which also affects the outcome achieved when fabricating the implant supported dental prosthesis.…”