Intervertebral disc therapies for non-specific chronic low back pain: a systematic review and meta-analysis

Objectives: We aim to evaluate the benefits and harms of intervertebral disc therapies (IDTs) in people with non-specific chronic low back pain (NScLBP). Methods: We conducted a systematic review and meta-analysis of randomized trials of IDTs versus placebo interventions, active comparators or usual care. EMBASE, MEDLINE, CENTRAL and CINHAL databases and conference abstracts were searched from inception to June 2020. Two independent investigators extracted data. The primary outcome was LBP intensity at short term (1 week-3 months), intermediate term (3-6 months) and long term (after 6 months). Results: Of 18 eligible trials (among 1396 citations), five assessed glucocorticoids (GCs) IDTs and were included in a quantitative synthesis; 13 assessed other products including etanercept (n = 2), tocilizumab (n = 1), methylene blue (n = 2), ozone (n = 2), chymopapaine (n = 1), glycerol (n = 1), stem cells (n = 1), platelet-rich plasma (n = 1) and recombinant human growth and differentiation factor-5 (n = 2), and were included in a narrative synthesis. Standardized mean differences (95% CI) for GC IDTs for LBP intensity and activity limitations were -1.33 (-2.34; -0.32) and -0.76 (-1.85; 0.34) at short term, -2.22 (-5.34; 0.90) and -1.60 (-3.51; 0.32) at intermediate term and -1.11 (-2.91; 0.70) and -0.63 (-1.68; 0.42) at long term, respectively. Odds ratios (95% CI) for serious and minor adverse events with GC IDTs were 1.09 (0.25; 4.65) and 0.97 (0.49; 1.91). Conclusion: GC IDTs are associated with a reduction in LBP intensity at short term in people with NScLBP. Positive effects are not sustained. IDTs have no effect on activity limitations. Our conclusions are limited by high heterogeneity and a limited methodological quality across studies.