✓Numerous new posterior dynamic stabilization (PDS) devices have been developed for the treatment of disorders of the lumbar spine. In this report the authors provide a classification scheme for these devices and describe several clinical situations in which the instrumentation may be expected to play a role. By using this classification, the PDSs that are now available and those developed in the future can be uniformly categorized.

C-SoFTs are rare central nervous system, typically dural-based, tumors. They frequently are overlooked in the differential diagnosis of solid central nervous system tumors. Our findings suggest that these tumors can occur at any age and in most locations, regardless of proximity to the meninges (basal ganglia and ventricle), suggesting that the cells of origin are not meningothelial, but rather the mesenchyme of the cerebral vasculature. T1- and T2-weighted magnetic resonance imaging was notable for areas of hypointensity and of hyperintensity best described as patchy or a ying-yang appearance in all cases. Delayed extracranial metastasis may be noted.