Defining the use of gadolinium enhanced MRI in the assessment of the postoperative lumbar spine.

A retrospective study of case notes and magnetic resonance imaging (MRI) examinations was performed to assess the value of gadolinium enhanced MRI in the investigation of persistent back pain following lumbar spine surgery in patients who have not had a discectomy for disc herniation. Gadolinium enhancement is commonly used during MRI of patients with persistent back pain following surgery and epidural scar is frequently identified in patients who have had a previous discectomy. However the value of gadolinium enhancement in patients without previous discectomy had not been addressed. One hundred sets of case notes were examined and 24 patients with an accurate history of previous lumbar spine surgery without discectomy were identified. The nature of surgery and the MRI findings were correlated in these patients. Epidural enhancement was identified at seven sites in six patients (engorged epidural venous plexus, three; enhancement adjacent to degenerate discs, two; enhancement adjacent to facets, two). In no case was epidural scarring involving nerve roots identified. We conclude that routine gadolinium enhancement is unnecessary in patients without a history of discectomy for disc herniation.