Interlaminar Epidural Steroid Injection for Degenerative Lumbar Spinal Canal Stenosis: Does the Intervertebral Level of Performance Matter?

Background: Interlaminar epidural steroid injections (ILESIs) are commonly employed in the management of patients with symptomatic degenerative lumbar spinal canal stenosis despite little experimental evidence to guide technique optimization. One untested performance parameter is the intervertebral level at which the ILESI should be performed for maximum patient relief. Methods: This study randomized patients with symptomatic degenerative lumbar spinal canal stenosis to receive an ILESI at the level of maximal spinal canal stenosis or at a normal/less stenotic intervertebral site 2 intervertebral levels cephalad to the level of maximal stenosis. Pain with ambulation and Roland Morris Disability Questionnaire scores were collected prior to the procedure and at 1-, 4-, and 12-week follow-ups. Results: Fifty-seven patients were enrolled. Thirty patients (Group 1) received an ILESI at the level of maximal stenosis; 27 patients (Group 2) received an ILESI at a less stenotic level. The mean baseline preprocedural maximal pain with ambulation and disability scores for the 2 groups were not significantly different (P=0.94 and P=0.13, respectively). Patients' pain with ambulation scores were significantly lower in Group 1 compared to Group 2 at 1 and 4 weeks postinjection, but they were not significantly lower at 12 weeks (1 week, P=0.045; 4 weeks, P=0.049; 12 weeks, P=0.08). The mean Roland Morris Disability Questionnaire scores at 1, 4, and 12 weeks postinjection were significantly lower in Group 1 as compared to Group 2 (P=0.001, P=0.009, P=0.003, respectively). Conclusion: Results suggest that patient symptom improvement is optimized when the ILESI is performed at the intervertebral level of maximal stenosis.