The so-called liberation procedure uses balloon angioplasty or stenting to widen blood vessels that drain the brain and spinal cord. Its use in MS is based on a theory advanced in 2009 by Paolo Zamboni, MD, of the University of Ferrara in Italy. Using evidence from imaging to support his claim, Zamboni argued that patients with MS may have chronic cerebrospinal venous insufficiency (CCSVI), which leads to iron buildup in the central nervous system and an immune or inflammatory reaction (Singh AV and Zamboni P. J Cereb Blood Flow Metab. 2009;29[12]:1867-1878). But subsequent studies have produced conflicting findings, with several groups reporting they were unable to replicate the findings of Zamboni and his colleagues. Meanwhile, others have questioned the biological plausibility of the theory.