Recurrent post-discectomy pain. CT--surgical correlation

Diagnostic evaluation of the patient with recurrent lumbosacral radiculopathy following lumbar laminectomy and discectomy represents a difficult task for the radiologist. Neither non-enhanced CT nor myelography have permitted reliable differentiation between postoperative extradural fibrosis (scarring) and recurrent disc herniation. However, CT following intravenous contrast infusion has been reported by several investigators to allow differentiation of these two entities. A series of 13 patients is reported with correlation between the findings on postcontrast CT and at reoperation. In 5 patients who exhibited variable contrast enhancement of an extradural soft tissue mass without a discreet lucent component on postcontrast CT, operative reexploration revealed only scar tissue. In 8 patients in whom postcontrast CT demonstrated a discreet non-enhancing extradural mass (partially surrounded by a thin enhancing rim of soft tissue in all but one), recurrent disc herniation together with an overlying band of scar was found and resected at reoperation. The strong positive correlation between CT and operative findings in this series suggests that postcontrast CT may well prove to be a reliable method for preoperative differentiation of recurrent disc herniation from extradural scarring.