In 1956, an important paper by Davies was published ([1]), which detailed findings in 124 patients at surgery up to a year after myelography. 60% showed immediate reaction and 12% developed "chronic adhesive meningitis"; Davies suggested a 3% incidence of severe chronic arachnoiditis.
[1] Davies FL Lancet 1956; 2: 747 Effect of unabsorbed radiographic contrast media on the central nervous system.
