Epidural tissue reaction post interlaminar particulate steroid injection: A case series and systematic review

Lumbar radicular pain is often treated with interlaminar epidural particulate corticosteroid injection (ILEPSI). However, little literature exists on epidural tissue changes post ILEPSI. Investigating these potential tissue changes is valuable because of their possible clinical implications.

To report gross and histological epidural tissue changes after ILEPSI following spinal decompression surgery and compare the observed changes to those previously reported in the literature.

A retrospective case series and systematic literature review were conducted. Surgeons were blinded to the details of corticosteroid injections and the study's specific aims.

Patients who underwent spinal decompression surgery and through retrospective chart review were found to have had ILEPSI prior to surgery.

Four consecutive patients undergoing spinal decompression surgery were included in a convenience sample, all exhibiting abnormal epidural tissue formation. A retrospective chart review showed that each patient had received ILEPSI at the same spinal level before surgery. A systematic literature review, registered in International Prospective Register of Systematic Reviews, was subsequently conducted based on this novel finding.

Surgical biopsies from four patients undergoing spinal decompression after ILEPSI showed "granulomatous-like reactions" in the epidural space. A systematic literature review found no similar epidural reactions but did find comparable findings in dermatology literature.

The epidural "granulomatous-like reactions" observed after ILEPSI are a novel finding, resembling tissue reactions from particulate corticosteroid administration. This suggests a potential link between ILEPSI and these reactions.