Female, 51 years old, with epidural abscess status post debridement. There is been interval removal of the interbody cage at L4-5, posterior left iliac crest bone graft, and interbody fusion at L4-5. Revision hemi-laminotomies at L1-2, L4-5 and L5-S1 have also been performed. There is a small fluid collection within the posterior left iliac crest defect, with surrounding likely surgical packing material (T2 hypointense signal) and enhancement, which is nonspecific.Previously demonstrated ventral epidural fluid collection from L1 through L3 appears to be resolved. A persistent fluid collection involving the left laminotomy defect at L4-L5 is slightly increased in size since 8/12/2016 with encroachment on the dorsolateral left aspect of the thecal sac. A smaller fluid collection with surrounding enhancement is also again demonstrated in the paraspinal soft tissues at the level of the L2-3 left hemilaminotomy. Heterogeneous signal representing likely a combination of postoperative fluid and blood products within the ventral epidural space at L4 and L5 is slightly increased in size since prior examination. There is also enhancing granulation tissue on the left at this level. The combination causes mild to moderate effacement of the thecal sac and severe effacement of the left lateral recess with extension into the left L4-5 neural foramen. Bone graft placement may be better assessed with CT of the lumbar spine.Spinal alignment is anatomic. Lumbar vertebral body heights are preserved. There is prominent Schmorl's node and mild loss of anterior vertebral body height at T12. Signal changes at L4-5 are seen which may be postoperative in nature. No significant disc degeneration is detected.Within the posterior subcutaneous soft tissues in the midline, there is again a fluid collection, which is smaller than on prior exam, with surrounding enhancement and edema.
1. Postoperative findings are seen compatible with removal of interbody cage and interbody fusion at L4-5 and multilevel laminectomy for debridement of a large epidural abscess involving a majority of the spine. Resolved epidural fluid in the upper and mid lumbar spine.2. Likely postoperative fluid blood products and granulation tissue at the L4 and L5 levels causes severe effacement of the left lateral recess and extending into the left L4-5 neural foramina. Residual abscess cannot be completely excluded. 3. Fluid collections in the region of left iliac bone graft, left L2-3 and L4-5 paraspinal soft tissues, and posterior superficial subcutaneous soft tissues are most likely postoperative in nature. However, infection cannot be excluded.