What is difference between interlaminar and transforaminal lumbar epidural steroid injections (ESIs)?

Updated: Aug 06, 2018
  • Author: Boqing Chen, MD, PhD; Chief Editor: Stephen Kishner, MD, MHA  more...
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More evidence favors the use of transforaminal ESIs in the lumbar spine compared with the cervical spine. Although the interlaminar approach (see Approaches for Epidural Injections) may allow the injectate to flow to the site of pathology by migrating around the thecal sac and into the ventral epidural space, the transforaminal route is presumably more reliable for delivering the steroid to the affected area in cases of disk herniation in which the disk comes into contact with the nerve root.

Rhee and colleagues found a difference in patients undergoing interlaminar and transforaminal ESI. [13] Those patients who underwent transforaminal injections had a 46% reduction in their pain score, and 10% went on to need surgery. In contrast, patients who had interlaminar injections had a 19% reduction in pain, and 25% required surgery.

Recently, a randomized, prospective, blinded, and controlled trial on the 38 patients with lumbar subacute radicular pain was conducted. The study demonstrated that while both groups improved, the transforaminal ESIs provided better pain relief in up to 16 days post injections compared with the interlaminar group. [14]

However, a separate randomized and prospective research study enrolled 32 patients in each group with chronic lumbar radiculopathy and 6 months follow up; the study again revealed the improvement in pain and disability in both groups. However, no significant differences were noted in pain reduction and the Oswestry disability scale between the transforaminal and interlaminar groups at the end of 6 months. [15]

The above discrepancy of efficacy may be due to the lower response to epidural steroid injections in general because of the chronicity of the radiculopathy; alternatively, it may reflect the differences of timing in follow up between the 2 studies. It is generally agreed that ESIs offer short-term (several months) pain relief.

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