A Randomized, Double-Blind Controlled Trial
of Lumbar Interlaminar Epidural Injections in
Central Spinal Stenosis: 2-Year Follow-Up
Authors: Manchikanti Laxmaiah 
Published: February 2021

Background: While low back pain is the number one cause of disability in the United States,
lumbar spinal stenosis along with intervertebral disc herniation and degenerative spondylolisthesis
is one of the 3 most common diagnosis of low back and leg pain for which surgery is performed.
Numerous modalities of treatments including drug therapy and complex surgical fusions have been
recommended for treatment of central spinal stenosis. Epidural injections are one of the commonly
performed nonsurgical interventions in managing central spinal stenosis; however, there has been
paucity of literature in reference to efficacy of epidural injections in managing central spinal stenosis
with lumbar interlaminar epidural injections.
Study Design: A randomized, double-blind, active controlled trial.
Setting: Private interventional pain management practice and specialty referral center in the United
States.
Objective: To assess the effectiveness of lumbar interlaminar epidural injections with or without
steroids in providing effective and long-lasting pain relief with improvement in functional status for the
management of chronic low back and lower extremity pain related to lumbar central spinal stenosis.
Methods: A randomized, double-blind, active-control trial was designed with the inclusion of 120
patients assigned to 2 groups. Group I patients received lumbar interlaminar epidural injections
of local anesthetic (lidocaine 0.5%) 6 mL, whereas Group II received lumbar interlaminar epidural
injections with local anesthetic (lidocaine 0.5%) 5 mL mixed with 1 mL of steroids and 6 mg of
betamethasone.
Outcomes Assessment: Outcomes were assessed utilizing the numeric pain rating scale (NRS) and
Oswestry Disability Index (ODI) at 3, 6, 12, 18, and 24 months post treatment. The primary outcome
measure was significant improvement, defined as 50% improvement in pain and disability scores.
Results: Significant relief and functional status improvement was seen in 72% and 73% of patients
in Groups I and II at the end of 2 years considering all participants; however, this was 84% and
85% in the successful group. Overall significant improvement was achieved for 65.7 ± 37.3 weeks
in Group 1 and 68.9 ± 37.7 weeks in Group II at the end of 2 years when all participants were
considered; whereas, this was 77 ± 27.8 weeks and 77.9 ± 30.2 weeks when they were separated
into successful categories. The average number of procedures per patient was 5 to 6 in both groups.
Limitations: Limitations of this trial include lack of placebo control group and treatment of
patients with multiple procedures over a period of 2 years.
Conclusion: Lumbar interlaminar epidural injections of local anesthetic with or without steroids
provide relief in a significant proportion of patients with lumbar central spinal stenosis.
Key words: Chronic low back pain, lower extremity pain, central spinal stenosis, interlaminar
epidural injections, caudal epidural injections, steroids, local anesthetics, placebo, active control