Tumors of the spine

Figure 1 The (absent) pedicle sign known as the winking owl sign (arrow). A reliable sign of osteolytic spinal metastases on antero-posterior radiographs is loss of the normal pedicle contour.

Figure 2 The Weinstein-Boriani-Biagini surgical staging system[13]. In this classification, the spine is radially divided into 12 equal radial segments (clock-face) in axial plane and examined in 5 layers from superficial to deep plane. Adapted with permission from Spine 1997; 22(9):1036-1044.

Figure 3 Schematic diagram of surgical classification of spinal tumors according to Tomita et al[15]. Adapted with permission from Spine 2001; 26(3): 298-306.