The postoperative myelogram. Radiographic evaluation of arachnoiditis and dural/arachnoidal tears.

Either arachnoriditis or dural/arachnoidal tears may cause symptoms in the postoperative spinal patient. Surgery and myelography as causes of arachnoiditis are discussed. Intradural arachnoid cyst formation and intramedullary cavitation may present as unusual sequelae of arachnoiditis. Extra-dural cysts and cerebrospinal fluid fistulas resulting from dural/arachnoidal tears are unusual postoperative complications presenting striking myelographic features. Their mechanisms of formation, clinical significance, and radiographic features are discussed.