Gadolinium-DTPA-enhanced MRI of the asymptomatic postdiscectomy lumbar spine: early postoperative results

We studied 30 patients with an uncomplicated clinical course after surgery for lumbar disc herniation, using gadolinium (Gd)-DTPA-enhanced 0.35 T spin-echo MRI within 4–12 days of operation: the goal was to define the normal healing process following this type of surgery. At surgery we found disc protrusion (10%), herniation (57%), or sequestration (33%). Postoperative MRI demonstrated major protrusion in 4% and minor protrusion in 27%. There was strong epidural enhancement in 83% and moderate enhancement in 17%. The enhancing tissue had mass effect in 67% of cases. Delineation of intraspinal structures was excellent after administration of Gd-DTPA. Although Gd-DTPA-enhanced MRI of the postdiscectomy lumbar spine gives good visualization of the intraspinal space, the rather high incidence of abnormalities seen on MRI in asymptomatic patients clearly demonstrates that post-operative assessment still depends strongly upon clinical examination, and that neuroimaging, however sophisticated, has a complementary role in the process of medical decision making.