The postoperative lumbar spine: imaging considerations.

MRI with intravenous contrast has recently become the imaging modality of choice in the evaluation of patients developing recurrent back pain or symptoms following laminectomy and/or discectomy. The normal postoperative appearance is important to recognize because a number of changes occur normally throughout the healing period. The difference between epidural scar and recurrent disc herniation can usually be determined on MRI. Postoperative fluid collections may also develop. Disc space infection, although uncommon, is a critical diagnosis, but can be confused with degenerative end plate changes. Arachnoiditis and spinal stenosis also show characteristic imaging findings.