Epidural steroid injections are associated with less improvement in patients with lumbar spinal stenosis: a subgroup analysis of the Spine Patient Outcomes Research Trial.

STUDY DESIGN: Subgroup analysis of prospective, randomized database from the Spine Patient Outcomes Research Trial (SPORT).

OBJECTIVE: The hypothesis of this study was that patients who received ESI during initial treatment as part of SPORT (The Spine Patient Outcomes Research Trial) would have improved clinical outcome and a lower rate of crossover to surgery than patients who did not receive ESI.

SUMMARY OF BACKGROUND DATA: The use of epidural steroid injection (ESI) in patients with lumbar spinal stenosis is common, although there is little evidence in the literature to demonstrate its long-term benefit in the treatment of lumbar stenosis.

METHODS: Patients with lumbar spinal stenosis who received ESI within the first 3 months of enrollment in SPORT (ESI) were compared with patients who did not receive epidural injections during the first 3 months of the study (no-ESI).

RESULTS: There were 69 ESI patients and 207 no-ESI patients. There were no significant differences in demographic factors, baseline clinical outcome scores, or operative details between the groups, although there was a significant increase in baseline preference for nonsurgical treatment among ESI patients (ESI 62% vs. no-ESI 33%, P < 0.001). There was an average 26-minute increase in operative time and an increased length of stay by 0.9 days among the ESI patients who ultimately underwent surgical treatment. Averaged over 4 years, there was significantly less improvement in 36-Item Short Form Health Survey (SF-36) Physical Function among surgically treated ESI patients (ESI 14.8 vs. no-ESI 22.5, P = 0.025). In addition, there was significantly less improvement among the nonsurgically treated patients in SF-36 Body Pain (ESI 7.3 vs. no-ESI 16.7, P = 0.007) and SF-36 Physical Function (ESI 5.5 vs. no-ESI 15.2, P = 0.009). Of the patients assigned to the surgical treatment group, there was a significantly increased crossover to nonsurgical treatment among patients who received an ESI (ESI 33% vs. no-ESI 11%, P = 0.012). Of the patients assigned to the nonoperative treatment group, there was a significantly increased crossover to surgical treatment in the ESI patients (ESI 58% vs. no-ESI 32%, P = 0.003).

CONCLUSION: Despite equivalent baseline status, ESIs were associated with significantly less improvement at 4 years among all patients with spinal stenosis in SPORT. Furthermore, ESIs were associated with longer duration of surgery and longer hospital stay. There was no improvement in outcome with ESI whether patients were treated surgically or nonsurgically.