“…Clinical signs associated with foreign bodies in the vertebral canal can be caused by direct injury to the spinal cord by the foreign material, or related to haemorrhage, infection or granuloma formation secondary to the intruding material (Johnston and Summers 1971, Brockman and Trout 1991, Pratt and others 1999, Rayward 2002, Leskovar and others 2003, Dennis and others 2005, Granger and others 2007, Mateo and others 2007, Platt and others 2007, Hicks and Bagley 2008, Smith and Fitzpatrick 2009, Joslyn and others 2010, Schneider and others 2010, Sutton and others 2010, Potanas and others 2011, Tanaka and others 2012, Whitty and others 2013). Needles are very thin and of an inert material, so direct injury of the spinal cord should be theoretically minimal.…”