Pelvic symmetry studied with the segmentation software Materialise for the treatment of acetabulum fractures in Traumatology

This Master Thesis aims to assist orthopedic surgeons in the treatment of pelvic fractures while using osteosynthesis plates. To fabricate pre-operatively patient-specific plates and facilitate the surgical planning process, 3D virtual pelvis models are developed due to the complex structure of the bony pelvis. Modelling helps to understand the characteristics of the fracture and to decrease the duration of surgery and therefore the risk of bleeding. Thus, it improves immediate and longer-term post-operative results. Currently, these models use the healthy contralateral hemi-pelvis to visualize the fractured hemi-pelvis before the fracture. Consequently, perfect symmetry of the pelvis is assumed. In addition, clinical assessment of surgical treatment is based on criteria such as the Matta scoring system, which also involves symmetry of the pelvis. However, morphological changes related to age and sex can lead to asymmetry of the pelvis. In particular, male and female pelvises evolve differently, due to biological functions such as childbirth for women. Consequently, it is crucial to determine whether or not the pelvis can be considered symmetrical in order to construct the 3D virtual image of the fractured pelvis before the fracture. In this work, modelling tools are used to compare global and local symmetries of pelvis. Therefore, similarities in regions of interest (defined by the orthopedic surgeon) are analyzed on the basis of CT scan images collected from a cohort of 28 patients with of healthy pelvis. Images are reconstructed in 3D by meshing the pelvic surface with a segmentation software called Materialize Mimics. Then, the 3-Matic processing software is used to improve meshing and extract the data needed to carry out all the measurements in this study. Then, Matlab programming is used to compare the hemi-pelvises, in terms of volume, surface area, distance from the plane of symmetry and deviation of the surface. Finally, the influence of age and sex of patients on the properties of pelvic symmetry is explored.