Purpose: To determine if axial low back pain (LBP) associated with central disc protrusions can be improved by caudal epidural steroid injections (ESIs).
Methods: Adults with chronic (> 3 months) moderate-to-severe axial LBP with L4-5 and/or L5-S1 central disc protrusions were enrolled in this prospective study. Participants underwent caudal ESIs under standard-of-care practice. The numerical rating scale (NRS) pain score, modified North American Spine Society satisfaction, and Roland Morris Disability Questionnaire (RMDQ) were collected at one week, one month, three months, six months, and one year post-injection. Pre-injection magnetic resonance images were assessed by a musculoskeletal radiologist.
Results: Sixty-eight participants (42 males, 26 females) were analyzed. There were statistically significant improvements in all outcome measures at all follow-up time points, with the exception of NRS best pain at six months. Clinically significant improvements in outcomes were observed at various time points: at three months and one year for current pain; at one week, one month, three months, six months, and one year for worst pain; and at one month and one year for RMDQ. The proportion of satisfied participants ranged from 57 to 69% throughout the study. No adverse events were observed.
Conclusions: This study demonstrated significant improvements in pain and function following caudal ESIs in a cohort of axial LBP with associated central disc protrusions. Further studies, including the use of randomized controlled trials, are needed to determine the ideal subset of candidates for this treatment and to explore additional applications that caudal ESIs may have for chronic LBP.
Keywords: Axial; Caudal epidural steroid injection; Central disc protrusion; Low back pain; Outcomes.