Background: This study aims to provide epidemiological data concerning spinal instability and patterns of metastatic invasion of the spine based on tumor histology. Methods: We allocated 285 patients with spinal metastatic disease through a retrospective review. SINS was calculated using good-quality computed tomography (CT) imaging studies. Spinal metastases were also grouped into intracompartmental, extracompartmental or multiple metastases. Results: Esophageal cancer was the least likely to be associated with instability with about 64% of cases being stable. The highest rate of instability scores was observed in breast carcinoma with 18% of cases graded as unstable. Renal cell carcinoma was associated with lytic spinal metastases whereas blastic metastases mostly occurred in prostate carcinoma (P<0.001). Whereas 68.1% of cases represented multiple metastases, the remainder was associated with either intracompartmental (13.3%) or extracompartmental (18.6%) disease. The highest degrees of spinal instability (intermediate and unstable categories) were associated with extra-compartmental metastatic disease (P<0.001). Conclusions: This study sheds light on the patterns of spinal metastatic disease and mechanical instability on the basis of tumor histology, utilizing standardized scoring systems. The utilization of such scoring systems allows for a standardized approach towards description and analysis of spinal metastasis facilitating clinical research in this avenue.