Development of Synthetic Lumbar Vertebrae using Custom-made Mould for Orthopaedics Training: Micro-Structural Analysis

Abstract

Human vertebrae composed of cortical and cancellous bone are crucial to provide the structural support of human framework and protect the organs underneath. Vertebrae from the Lumbar 3 (L3) was selected for fabrication because it is the most commonly used for surgical training. The use of human vertebrae in the orthopaedic studies is necessary to investigate various complications such as vertebral compression fracture and to propose the most suitable medical intervention for the treatment. However, investigations of cortical and cancellous material properties and composition have been limited. Therefore, the main objective of this study was to design a custom-made mould for synthetic lumbar vertebrae using moulding techniques that could exhibit the same anatomical structure as real vertebrae. Then, this study was carried out to establish a process of cortical and cancellous synthetic bone development. Lastly, this study was done to compare the morphological properties of synthetic bone produced with human bone. Utilizing Polyurethane (PU) as the main material was used for the fabrication, where it could inhibit the morphological properties that could mimic the human bone. The methods to fabricate the vertebrae also varied from static mould and rotational mould. The fabricated lumbar produced was tested for the morphological properties, targeting the pore diameter, was performed using Scanning Electron Microscopy (SEM). From this study, it was identified that the analysis of pore diameter from specimen of Ratio 3 from rotational mould depicts the smallest pore diameter and standard deviation, 1.5 ± 0.3 mm. While this specimen has the smallest value, the results were still higher when compared to the pore diameter of human trabecular bone (which ranges from 0.3 mm to 0.6 mm). In conclusion, the use of silicone custom-made moulds could provide synthetic vertebrae with an anatomical structure mimicking real human vertebrae.