Vertebral metastases affect one third of metastatic patients. They compromise bone integrity, often leading to fracture and neurological damage. The risk of fracture of a metastatic vertebra is currently estimated by the Spinal Instability Neoplastic Score (SINS). However, SINS is mostly qualitative, and lacks assessment of vertebral mechanics. The present thesis is part of the qSINS (i.e. quantitative SINS) project, conceived at the Bioengineering and Computing (BIC) Laboratory of IRCSS Istituto Ortopedico Rizzoli and funded by the Italian Ministry of Health (RF-2016-02364359). The main challenge of qSINS is to develop subject-specific finite elements models (SSFE) based on CT images routinely collected to stage the disease.