Before proceeding to revision spine surgery verify everything radiologically as Pseudarthrosis is likely when motion is present on flexion-extension radiographs. However, controversy exists regarding the amount of motion that is compatible with a solid fusion. Criteria range from no motion to 5 degrees of motion and radiological assessment of sagittal balance and lastly Plain x ray pelvis to see any joint pathology. CT scan assessed for evidence of pseudarthrosis such as screw loosening or hardware failure, Lucencies around the hardware, any iatrogenic pars defect, laminectomy defect, extent of facetectomy, posterolateral interbody fusion status. CT myelography: This is useful for patients in which (MRI) scan is difficult due to metal artifact or in scoliosis due to the deformity and in a patient with pacemaker. MRI- especially epidural scar, recurrent disk herniation and demonstrate the presence of postoperative infection.