Although epidural steroid injections (ESIs) are a common treatment for lumbar spinal stenosis, data presented at the 2011 annual meeting of the North American Spine Society indicate that long-term outcomes are worse for patients who receive them, compared to those who have never had an ESI. The study also found that patients who had received ESIs and later opted for surgical treatment tended to have a longer hospital stay and longer surgical times than those who did not receive ESIs.

Data were based on an analysis of patients enrolled in the Spine Patients Outcome Research Trial (SPORT), a 5-year, multicenter study that compared surgical and nonsurgical treatments for three common spine conditions, including spinal stenosis. Approximately 2,500 patients took part in the study, which included both randomized and observational cohorts.

ESIs address the inflammatory effect of nucleus pulposus on the lumbar nerve roots and also have an epidural lavage effect, according to presenter Kris E. Radcliff, MD, of the Rothman Institute at Thomas Jefferson University Hospital, Philadelphia. They are also associated with a relatively low complication rate and a desire to avoid surgery. Dr. Radcliffe and his coauthors hypothesized, therefore, that patients who received ESIs would have improved outcomes and a lower crossover rate to surgery at long term than those who do not receive ESIs.

Similar baseline status
The researchers identified 278 lumbar spinal stenosis patients enrolled in the SPORT study who had not received ESIs before enrollment. During the first 3 months of the study, 69 patients received ESIs (ESI cohort). Of these patients, 36 (52 percent) had severe stenosis, 31 (45 percent) had moderate stenosis, and 2 (3 percent) had mild stenosis. More than half (37 patients; 54 percent) had multilevel stenosis.

The remaining 207 patients did not have ESIs with the first 3 months of the study (no-ESI cohort). Of these patients, 114 (55 percent) had severe stenosis, 88 (43 percent) had moderate stenosis, and 5 (2 percent) had mild stenosis. Two thirds (135 patients; 66 percent) had multilevel stenosis.

Using standard outcomes measures, including the Short Form-36 (SF-36), Oswestry Disability Index (ODI), and Sciatica Bothersomeness Index (SBI), researchers compared results for the two cohorts at baseline and yearly up to 4 years.

At baseline, the researchers found no differences in functional outcome measures (Fig. 1) or perioperative factors—dural tear rate, surgical time, and hospital length of stay—between the two groups. Dr. Radcliff also noted that patients in the ESI group had a significantly lower preference for surgery than those in the no-ESI group.

Long-term outcomes
Of the 69 patients in the ESI cohort, 41 eventually underwent surgery; of the 207 patients in the no-ESI cohort, 134 had surgery. The most common surgery was decompression only.

Among those who did not have surgery, ESI patients showed significantly less improvement in SF-36 bodily pain (BP), SF-36 physical function (PF), and SF-36 physical component summary (PCS), and a trend toward less improvement in ODI, compared to no-ESI patients at 4-year follow-up. Similarly, among patients who eventually underwent surgery, patients in the ESI group showed significantly less improvement in SF-36 BP, ODI, SBI, and patient satisfaction, and a trend toward less improvement in SF-36 PCS, at 4 year follow-up, compared to no-ESI patients (Table 1).

The researchers found no statistically significant differences in surgical treatments, complications, adverse events, or reoperation rates between the ESI and no-ESI patients who had surgery. Patients who had received ESI, however, had longer surgical times and hospital lengths of stay (142.5 minutes and 3.6 days, respectively), compared to no-ESI patients (116 minutes and 2.7 days). The authors speculate that epidural scarring after injection may have increased surgical time.

Interestingly, the researchers also found an increased crossover rate both to and from surgery in patients who received ESIs. Among the patients who had been randomized to surgery at enrollment in SPORT, one third of those who received ESIs within the first 3 months of enrollment ultimately went on to have nonsurgical treatment, versus 11 percent in the no-ESI group (P < 0.012). Of the patients who had been randomized to nonsurgical treatment, 58 percent in the ESI group went on to have surgical treatment, versus 32 percent in the no-ESI group (P = 0.003). Therefore, ESIs were associated with increased crossover, regardless of assigned or chosen treatment.

Despite their hypothesis and equivalent baseline status between the two groups, the researchers concluded that patients with lumbar spinal stenosis who received ESIs exhibited less improvement and no definitive surgical avoidance at long term, compared to patients who did not receive ESI. Although patients may experience a short-term improvement in outcomes after ESIs, these data suggest that ESIs are associated with poorer outcomes over the long term.

Dr. Radcliff’s coauthors of “Do Epidural Steroid Injections Affect the Outcome of Patients Treated for Lumbar Stenosis? A Subgroup Analysis of the SPORT,” are Christopher Kepler, MD, MBA (no conflicts); Alan S. Hilibrand, MD (Aesculap/B. Braun; Alphatec Spine; Amedica; Biomet; Stryker; Zimmer; Benvenue Medical; Lifespine; Nexgen; Paradigm Spine; Pioneer Surgical; PSD; Spinal Ventures; Syndicom; Vertiflex); Wenyan Zhao (no conflicts); Jon D. Lurie, MD (Foundation for Informed Medical Decision Making; Baxano; Blue Cross/Blue Shield; Scientific Advisory Board; Sanofi-Aventis); Tor Tosteson, ScD (no conflicts); Jeffrey A. Rihn, MD (DePuy, A Johnson & Johnson Company); Todd J. Albert, MD (DePuy, A Johnson & Johnson Company; Bioassets; Biomerix; Breakaway Imaging; Crosstree; Gentis; International Orthopaedic Alliance; Invuity; Paradigm Spine; PIONEER; Reville Consortium; Vertech; United Healthcare; Saunders/Mosby-Elsevier; Thieme; Spine); and James N. Weinstein, DO, MS (Spine; American Board of Orthopaedic Surgery, Inc.). Dr. Radcliff reports no conflicts.

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Bottom line

• This subgroup analysis of the SPORT study looked at whether patients with spinal stenosis who received ESIs after enrollment in the larger study had improved outcomes and surgical avoidance compared to patients who did not receive ESIs.
• Compared to patients who did not receive ESIs at all, patients in this study who received ESIs showed significantly less improvement in multiple outcome measures at 4 years, regardless of type of treatment (surgical or nonsurgical).
• Patients who received ESIs and were surgically treated had longer surgeries and hospital stays than surgical patients who never received ESIs.
• Among the patients in this subgroup of the SPORT study who were randomized to surgery, those who received ESIs were more likely to cross over to nonsurgical treatment than those who never received ESIs. Similarly, among patients randomized to nonsurgical treatment, those who received ESIs were more likely to cross over to surgery than those who never received ESIs.