Metastatic spine tumors commonly affect the thoracic spine, and effective tumor control often requires corpectomy with reconstruction. In some instances, anterior approaches for corpectomy may be difficult or less than ideal because of medical co-morbidities, pulmonary disease or difficult access behind the mediastinum. Thus, posterior approaches are commonly used for corpectomies with anterior column reconstruction in the thoracic spine. Expandable cages have the advantage of restoring height, correcting kyphosis, and providing secure wedging between the vertebral bodies. However, the spinal cord and thorax may prevent direct, easy access for placement of expandable cages. Reconstruction has been performed with different materials; however, expandable cages have hitherto been less frequently used because of their size and difficulty expanding the cages posteriorly. We describe a technical note that may facilitate the placement of an expandable cage in the thoracic spine after posterior transpedicular corpectomies.