T1 pre-gad T1 post-gad T2 FSE

Diagnosis: Epidural fibrosis left S1 nerve root

Epidural fibrosis occurs when scar forms in association with the thecal sac and/or nerve roots after surgery. Patients may experience a recrudescence of their original radicular symptoms raising the possibility of recurrent disk. One of the major objectives in imaging patients with recurrent symptoms who have had surgery is to differentiate these two entities. Epidural fibrosis generally demonstrates isointense signal to annulus to T1 and increased signal compared to annulus on T2. The scar associated with epidural fibrosis may surround the affected nerve root and typically enhances. Furthermore, epidural fibrosis will occur at the level of the surgery. Signal of recurrent disk fragments generally follows that of disk annulus being relatively dark on T2 compared to epidural fibrosis. Recurrent disk may enhance but enhancement with recurrent disk tends to be more peripheral and does not surround the nerve root..

This patient is status post two L5 laminectomies in the past. Differentiation between recurrent disk and epidural fibrosis is important since patients with epidural fibrosis generally do not receive much benefit from repeat surgery while patients with recurrent disk have better results. Related Cases

Bundschuh CV, Modic MT, Ross JS, et al. Epidural fibrosis and recurrent disk herniation in the lumbar spine: MR imaging assessment. AJR, Apr 1988; 150(4):p923-32.

Mirowitz SA, Shady KL. Gadopentetate dimeglumine-enhanced MR imaging of the postoperative lumbar spine: comparison of fat suppressed and conventional T1 weighted images. AJR, Aug 1992; 159(2):p385-9.

Bundschuh CV, Stein L, Slusser JH, et al. Distinguishing between scar and recurrent herniated disk postoperative patients: value of contrast-enhanced CT and MR imaging. AJNR, Sep-Oct 1990; 11(5):p949-58.

Jinkins JR, Osborn AG, Garrett D, et al. Spinal nerve enhancement with Gd-DTPA: MR correlation with the postoperative lumbosacral spine. AJNR, Mar-Apr 1993; 14(2):p383- 94.

HNP Calcified HNP Epidural fibrosis