Single Intradiscal Administration of the Tumor Necrosis Factor-Alpha Inhibitor, Etanercept, for Patients with Discogenic Low Back Pain

OBJECTIVE: To examine the analgesic effect of intradiscal administration of a tumor necrosis factor-αα (TNF-α) inhibitor in patients with discogenic low back pain (LBP). DESIGN: Prospective, randomized study. SETTING: Department of Orthopaedic Surgery, Chiba (Japan) University Hospital. SUBJECTS: Seventy-seven patients diagnosed with discogenic LBP. METHODS: Discogenic LBP patients were randomly assigned to the etanercept (n = 38; bupivacaine [2 mL] with etanercept [10 mg]) or control (n = 39; bupivacaine [2 mL]) groups. Patients received a single intradiscal injection. Numerical rating scale (NRS) scores for LBP at baseline, 1 day, and 1, 2, 4, and 8 weeks after the injection were recorded. The Oswestry disability index (ODI) scores at baseline and at 4 and 8 weeks after injection were evaluated. Postinjection complications were recorded and evaluated. RESULTS: In the etanercept group, the NRS scores were significantly lower than in the control group at every time point after the injection for 8 weeks (P < 0.05). Similarly, 4 weeks after the injection, the ODI score was lower in the etanercept group than in the control group (P < 0.05). However, the ODI scores were not significantly different at 8 weeks. Complications were not observed. CONCLUSIONS: Single intradiscal administration of a TNF-α inhibitor can alleviate intractable discogenic LBP for up to 8 weeks. TNF-α may be involved in discogenic pain pathogenesis. This procedure is a novel potential treatment; longer-term effectiveness trials are required in the future.