Interlaminar vs. Transforminal Epidural Steroids for Lumbar Radicular Pain

AUSTIN, TX—Argument in the literature exists over interlaminar (IL) versus transforminal (TF) lumbar epidural steroid injection technique as the most effective therapy in lumbar radiculopathy. However, all studies to date have been retrospective, as reported in a presentation at the American Pain Society's 30th Annual Scientific Meeting.

After Institutional Review Board approval, Michael Perloff, MD, PhD, and colleagues from NYU-Hospital for Joint Diseases, New York, enrolled and randomized 42 age-matched patients with similar lower back pain and unilateral radicular symptoms in a double-blind trial to IL or TF epidural steroid injection from 2007–2009. Primary outcome measures were the Oswestry Disability Index Score and Numerical Rating Scale for daily pain. Prior to intervention and 10–16 days after injection, each patient was evaluated by patient questionnaire and physical exam by an independent physician.

Evaluating physicians were blinded to the type of epidural steroid injection. If patients had <75% pain relief and did not experience satisfactory improvement, they were eligible for a second epidural steroid injection of the same type after 2–4 weeks. If this failed provide >75% relief, patients could cross to the alternate injection type.

Of the 42 patients, 38 completed the study, 18 in the IL and 20 in the TF group. In both groups, two patients required repeat injection, and one patient crossed over to the alternative injection type. Overall, physical exam, diagnostic testing, disability, activity and depression measures, and opioid pill use, were similar between the two groups, both pre-injection baseline and post-injection improvement. Oswestry Disability Index Score was reduced with similar significance for both IL and TF epidural steroid injection. Pain Numerical Rating Scale, however, was more greatly reduced in the TF group (P<0.05). See Table.

According to the results, Dr. Perloff et al. suggest that patients may at least initially experience greater subjective relief from TF epidural steroid injections over IL. However, more objective, and likely subacute, therapeutic effects are similar.