ANATOMIC DISTRIBUTION OF METASTASES IN THE VERTEBRAL BODY AND MODES OF HEMATOGENOUS SPREAD

Study Design. A retrospective review of the magnetic resonance spine e xaminations of 49 patients with metastatic bone disease to the spine w as performed. Objectives. To determine whether the pattern of metastat ic distribution in the spine correlates with the type of primary tumor and theoretical mode of hematogenous spread by arterial or venous rou tes. Summary of Background Data. In 1940, Batson theorized a venous pl exus route by which tumors spread to the spine from pelvic tumors such as prostatic carcinoma. If this theory is true, the venous vascular a natomy of the spine would result in metastases being deposited in the central or posterior vertebral body, whereas arterial deposits would o ccur near the endplates. Methods. Each vertebral body was divided into 27 equal cells in the magnetic resonance images; the central and post erior cells in the midsagittal view were defined as central, and the o ther cells were defined as peripheral. The primary tumor was assigned to either the arterial or venous group based on Batson's proposed mode of spread. The average number of lesions per involved vertebral body in the central and peripheral regions was calculated. Results. There w as no statistically significant correlation between tumors with propos ed arterial/venous routes of metastasis and central/peripheral locatio n of metastatic deposits. Conclusion. The mechanism by which tumors sp read to the vertebral body may not be via a pure arterial or venous ro ute. Other mechanisms such as tissue specificity, cascade system, and closed loop circulation system may be involved.